U.S. patent application number 11/272249 was filed with the patent office on 2006-06-22 for parallel reactor with internal sensing and method of using same.
This patent application is currently assigned to Symyx Technologies, Inc.. Invention is credited to G. Cameron Dales, Damian A. Hajduk, Paul Mansky, Leonid Matsiev, Eric McFarland, Ralph B. Nielsen, Johannes A.M. van Beek.
Application Number | 20060133968 11/272249 |
Document ID | / |
Family ID | 32931667 |
Filed Date | 2006-06-22 |
United States Patent
Application |
20060133968 |
Kind Code |
A1 |
Dales; G. Cameron ; et
al. |
June 22, 2006 |
Parallel reactor with internal sensing and method of using same
Abstract
Devices and methods for controlling and monitoring the progress
and properties of multiple reactions are disclosed. The method and
apparatus are especially useful for synthesizing, screening, and
characterizing combinatorial libraries, but also offer significant
advantages over conventional experimental reactors as well. The
apparatus generally includes multiple vessels for containing
reaction mixtures, and systems for controlling the stirring rate
and temperature of individual reaction mixtures or groups of
reaction mixtures. In addition, the apparatus may include
provisions for independently controlling pressure in each vessel,
and a system for injecting liquids into the vessels at a pressure
different than ambient pressure. In situ monitoring of individual
reaction mixtures provides feedback for process controllers, and
also provides data for determining reaction rates, product yields,
and various properties of the reaction products, including
viscosity and molecular weight. Computer-based methods are
disclosed for process monitoring and control, and for data display
and analysis.
Inventors: |
Dales; G. Cameron;
(Saratoga, CA) ; van Beek; Johannes A.M.;
(Amsterdam, NL) ; Hajduk; Damian A.; (San Jose,
CA) ; Nielsen; Ralph B.; (San Jose, CA) ;
Mansky; Paul; (San Francisco, CA) ; Matsiev;
Leonid; (Cupertino, CA) ; McFarland; Eric;
(Santa Barbara, CA) |
Correspondence
Address: |
SENNIGER POWERS
ONE METROPOLITAN SQUARE
16TH FLOOR
ST LOUIS
MO
63102
US
|
Assignee: |
Symyx Technologies, Inc.
Santa Clara
CA
|
Family ID: |
32931667 |
Appl. No.: |
11/272249 |
Filed: |
November 10, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10401133 |
Mar 25, 2003 |
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|
11272249 |
Nov 10, 2005 |
|
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|
09724276 |
Nov 28, 2000 |
6890492 |
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|
10401133 |
Mar 25, 2003 |
|
|
|
09548848 |
Apr 13, 2000 |
6455316 |
|
|
09724276 |
Nov 28, 2000 |
|
|
|
09239223 |
Jan 29, 1999 |
6489168 |
|
|
09548848 |
Apr 13, 2000 |
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|
09211982 |
Dec 14, 1998 |
6306658 |
|
|
09239223 |
Jan 29, 1999 |
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09177170 |
Oct 22, 1998 |
6548026 |
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09211982 |
Dec 14, 1998 |
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60096603 |
Aug 13, 1998 |
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Current U.S.
Class: |
422/130 |
Current CPC
Class: |
B01J 2219/00736
20130101; B01J 19/0006 20130101; G01N 35/1079 20130101; B01F
15/00207 20130101; B01L 2200/026 20130101; B01J 2219/00351
20130101; B01F 13/0818 20130101; B01J 2219/00373 20130101; B01F
15/00201 20130101; B01J 2219/00477 20130101; B01L 2300/14 20130101;
G01K 13/00 20130101; B01J 2219/00745 20130101; B01J 2219/00704
20130101; B01J 2219/00283 20130101; Y10T 436/11 20150115; B01J
2219/00686 20130101; C40B 40/18 20130101; B01J 2219/00698 20130101;
B01L 3/50853 20130101; B01L 2300/06 20130101; B01J 2219/00418
20130101; B01J 2219/00367 20130101; Y10T 436/119163 20150115; Y10T
436/115831 20150115; B01L 7/54 20130101; B01J 2219/00722 20130101;
B01J 2219/0059 20130101; B01L 2300/049 20130101; B01J 2219/00495
20130101; B01J 2219/00308 20130101; B01J 2219/0072 20130101; B01J
2219/00601 20130101; B01J 2219/00689 20130101; B01L 2300/1805
20130101; B01J 2219/00029 20130101; G01N 11/16 20130101; Y10T
436/25 20150115; B01J 2219/002 20130101; B01J 2219/00738 20130101;
B01J 2219/00702 20130101; B01J 2219/00389 20130101; B01J 19/0046
20130101; B01J 2219/00585 20130101; B01J 2219/00596 20130101; B01L
2300/0627 20130101; B01J 19/004 20130101; B01J 2219/00333 20130101;
B01J 2219/00162 20130101; B01J 2219/00691 20130101; B01J 2219/00481
20130101; B01J 2219/00695 20130101; B01F 13/0827 20130101; B01J
19/0013 20130101; B01L 3/50851 20130101; Y10T 436/25875 20150115;
B01J 2219/0031 20130101; Y10T 436/12 20150115; B01F 15/00246
20130101; B01J 2219/00335 20130101; C40B 40/14 20130101 |
Class at
Publication: |
422/130 |
International
Class: |
B01J 19/00 20060101
B01J019/00 |
Claims
1-162. (canceled)
163. A system for parallel processing of reaction mixtures, wherein
the system comprises: vessels for receiving the reaction mixtures,
said vessels being sealed against fluid communication with one
another and adapted for containing the reaction mixtures at
pressures greater than about 10 psig; a chamber enclosing the
vessels, the chamber being fillable with a suitable gas for
minimizing contamination of the reaction mixtures; a robotic
material handling system for loading the vessels with chemical
reaction materials; a stirring system adapted to agitate the
reaction mixtures; and a temperature control system adapted to
control the temperature of the vessels.
164. The system of claim 163 wherein the temperature control system
is operable to maintain a first group of the vessels at a different
temperature than a second group of the vessels.
165. The system of claim 163 wherein the chamber is substantially
impermeable to entry of a contaminant gas.
166. The system of claim 163 wherein the stirring system comprises
stirrers engageable with the reaction mixtures and a drive for
rotating the stirrers to stir the reaction mixtures.
167. The system of claim 166 wherein at least one stirrer comprises
a spindle having a first end and a second end and a stirring blade
attached to the first end of the spindle, the second end of the
spindle being magnetically coupled to the drive.
168. The system of claim 166 wherein at least one stirrer is a
magnetic stirring bar, and wherein the drive comprises an array of
electromagnets for producing rotating magnetic fields around the
stirring bar.
169. The system of claim 163 further comprising an injection system
for introducing chemical reaction materials into the vessels.
170. The system of claim 169 wherein the injection system is
operable to introduce chemical reaction materials into the vessels
when the vessels are at a pressure different than ambient
pressure.
171. The system of claim 163 further comprising at least two
reactor modules, each of said reactor modules comprising at least
one of said vessels.
172. The system of claim 163 further comprising pressure sensors
for measuring the pressure inside the vessels.
173. The system of claim 163 wherein the robotic handling system is
inside the chamber.
174. The system of claim 173 wherein the robotic handling system
comprises a moveable fluid delivery probe.
175. The system of claim 163 wherein the vessels contain the
reaction mixtures at pressures ranging between about 10 psig and
about 500 psi.
176. The system of claim 175 wherein the vessels contain the
reaction mixtures at pressures ranging between about 10 psig and
about 300 psi.
177. A method of parallel processing of reaction mixtures
comprising: using a robotic material handling system to load
chemical reaction materials into a plurality of vessels, said
vessels being sealed against fluid communication with one another
and adapted for containing the reaction mixtures at pressures
greater than about 10 psig; substantially enclosing the vessels in
a chamber; filling the chamber with a suitable gas for minimizing
contamination of the reaction vessels; agitating the reaction
mixtures; and controlling the temperature of at least some of the
vessels.
178. The method of claim 177 wherein the step of controlling the
temperature of at least some of the vessels comprising maintaining
a first group of the vessels at a different temperature than a
second group of the vessels.
179. The method of claim 177 wherein the step of filling the
chamber with a suitable gas comprises pressurizing the chamber with
the gas to a pressure greater than atmospheric.
180. The method of claim 177 wherein the step of agitating the
reaction mixtures comprises stirring the reaction mixtures.
181. The method of claim 180 wherein the stirring step comprises
rotating a plurality of stirrers engageable with the reaction
mixtures.
182. The method of claim 181 wherein at least one of said stirrers
comprises a spindle having a first end and a second end and a
stirring blade attached to the first end of the spindle, and
wherein the rotating step comprises using a drive system coupled to
the second end of the spindle to rotate said at least one
stirrer.
183. The method of claim 181 wherein at least one of said stirrers
comprises a magnetic stirring bar, and wherein the stirring step
comprises using an array of electromagnets to produce rotating
magnetic fields around said magnetic stirring bar.
184. The method of claim 177 further comprising injecting chemical
reaction materials into the vessels.
185. The method of claim 184 wherein the injecting step comprises
using the robotic handling system to move a fluid delivery probe
from a first vessel to a second vessel.
186. The method of claim 184 wherein the injecting step comprises
injecting chemical reaction materials into the vessels when the
vessels are at a pressure different than ambient pressure.
187. The method of claim 177 further comprising measuring the
pressure inside the vessels.
188. The method of claim 177 further comprising allowing the
reaction mixtures to react in the vessels at pressures ranging
between about 10 psig and about 500 psi.
189. The method of claim 188 further comprising allowing the
reaction mixtures to react in the vessels at at pressures ranging
between about 10 psig and about 300 psi
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/401,133, filed Mar. 25, 2003, which is a continuation of
U.S. application Ser. No. 09/724,276, filed Nov. 28, 2000, which is
a continuation of U.S. application Ser. No. 09/548,848, filed Apr.
13, 2000, now U.S. Pat. No. 6,455,316, which is a
continuation-in-part of U.S. application Ser. No. 09/239,223, filed
Jan. 29, 1999, now U.S. Pat. No. 6,489,168, and a
continuation-in-part of U.S. application Ser. No. 09/211,982, filed
Dec. 14, 1998, now U.S. Pat. No. 6,306,658, which is a
continuation-in-part of U.S. application Ser. No. 09/177,170, filed
Oct. 22, 1998, which claims the benefit of U.S. Provisional
Application No. 60/096,603, filed Aug. 13, 1998. All seven of the
foregoing applications are incorporated herein by reference in
their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates to methods, devices, and
computer programs for rapidly making, screening, and characterizing
an array of materials in which process conditions are controlled
and monitored.
[0004] 2. Discussion
[0005] In combinatorial chemistry, a large number of candidate
materials are created from a relatively small set of precursors and
subsequently evaluated for suitability for a particular
application. As currently practiced, combinatorial chemistry
permits scientists to systematically explore the influence of
structural variations in candidates by dramatically accelerating
the rates at which they are created and evaluated. Compared to
traditional discovery methods, combinatorial methods sharply reduce
the costs associated with preparing and screening each
candidate.
[0006] Combinatorial chemistry has revolutionized the process of
drug discovery. One can view drug discovery as a two-step process:
acquiring candidate compounds through laboratory synthesis or
through natural products collection, followed by evaluation or
screening for efficacy. Pharmaceutical researchers have long used
high-throughput screening (HTS) protocols to rapidly evaluate the
therapeutic value of natural products and libraries of compounds
synthesized and cataloged over many years. However, compared to HTS
protocols, chemical synthesis has historically been a slow, arduous
process. With the advent of combinatorial methods, scientists can
now create large libraries of organic molecules at a pace on par
with HTS protocols.
[0007] Recently, combinatorial approaches have been used for
discovery programs unrelated to drugs. For example, some
researchers have recognized that combinatorial strategies also
offer promise for the discovery of inorganic compounds such as
high-temperature superconductors, magnetoresistive materials,
luminescent materials, and catalytic materials. See, for example,
co-pending U.S. patent application Ser. No. 08/327,513 "The
Combinatorial Synthesis of Novel Materials" (published as WO
96/11878) and co-pending U.S. patent application Ser. No.
08/898,715 "Combinatorial Synthesis and Analysis of Organometallic
Compounds and Catalysts" (published, in part, as WO 98/03251),
which are all herein incorporated by reference.
[0008] Because of its success in eliminating the synthesis
bottleneck in drug discovery, many researchers have come to
narrowly view combinatorial methods as tools for creating
structural diversity. Few researchers have emphasized that, during
synthesis, variations in temperature, pressure, ionic strength, and
other process conditions can strongly influence the properties of
library members. For instance, reaction conditions are particularly
important in formulation chemistry, where one combines a set of
components under different reaction conditions or concentrations to
determine their influence on product properties.
[0009] Moreover, because the performance criteria in materials
science is often different than in pharmaceutical research, many
workers have failed to realize that process variables often can be
used to distinguish among library members both during and after
synthesis. For example, the viscosity of reaction mixtures can be
used to distinguish library members based on their ability to
catalyze a solution-phase polymerization--at constant polymer
concentration, the higher the viscosity of the solution, the
greater the molecular weight of the polymer formed. Furthermore,
total heat liberated and/or peak temperature observed during an
exothermic reaction can be used to rank catalysts.
[0010] Therefore, a need exists for an apparatus to prepare and
screen combinatorial libraries in which one can monitor and control
process conditions during synthesis and screening.
SUMMARY OF THE INVENTION
[0011] The present invention generally provides an apparatus for
parallel processing of reaction mixtures. The apparatus includes
vessels for containing the reaction mixtures, a stirring system,
and a temperature control system that is adapted to maintain
individual vessels or groups of vessels at different temperatures.
The apparatus may consist of a monolithic reactor block, which
contains the vessels, or an assemblage of reactor block modules. A
robotic material handling system can be used to automatically load
the vessels with starting materials. In addition to heating or
cooling individual vessels, the entire reactor block can be
maintained at a nearly uniform temperature by circulating a
temperature-controlled thermal fluid through channels formed in the
reactor block. The stirring system generally includes stirring
members--blades, bars, and the like--placed in each of the vessels,
and a mechanical or magnetic drive mechanism. Torque and rotation
rate can be controlled and monitored through strain gages, phase
lag measurements, and speed sensors.
[0012] In accordance with one aspect of the present invention,
there is provided a system for parallel processing reaction
mixtures. The system comprises vessels for receiving the reaction
mixtures. The vessels are sealed against fluid communication with
one another and are adapted for containing the reaction mixtures at
pressures greater than about 10 psig. A chamber encloses the
vessels. The chamber is fillable with a suitable gas for minimizing
contamination of the reaction vessels. The system has a robotic
material handling system for loading the vessels with chemical
reaction materials. A stirring system is adapted to agitate the
reaction materials. A stirring system is adapted to agitate the
reaction mixtures. A temperature control system is adapted to
control the temperature of at least some of the vessels.
[0013] In a method parallel processing reaction mixtures according
to the invention a robotic material handling system is used to load
chemical reaction materials into a plurality of vessels. The
vessels are sealed against fluid communication with one another and
are adapted for containing the reaction mixtures at pressures
greater than about 10 psig. The vessels are substantially enclosed
in a chamber. The chamber is filled with a suitable gas for
minimizing contamination of the reaction vessels. The reaction
mixtures are agitated. The temperature of at least some of the
vessels is controlled.
[0014] The apparatus may optionally include a system for evaluating
material properties of the reaction mixtures. The system includes
mechanical oscillators located within the vessels. When stimulated
with a variable-frequency signal, the mechanical oscillators
generate response signals that depend on properties of the reaction
mixture. Through calibration, mechanical oscillators can be used to
monitor molecular weight, specific gravity, elasticity, dielectric
constant, conductivity, and other material properties of the
reaction mixtures.
[0015] The present invention also provides an apparatus for
monitoring rates of production or consumption of a gas-phase
component of a reaction mixture. The apparatus generally comprises
a closed vessel for containing the reaction mixture, a stirring
system, a temperature control system and a pressure control system.
The pressure control system includes a pressure sensor that
communicates with the vessel, as well as a valve that provides
venting of a gaseous product from the vessel. In addition, in cases
where a gas-phase reactant is consumed during reaction, the valve
provides access to a source of the reactant. Pressure monitoring of
the vessel, coupled with venting of product or filling with
reactant allows the investigator to determine rates of production
or consumption, respectively.
[0016] One aspect of the present invention provides an apparatus
for monitoring rates of consumption of a gas-phase reactant. The
apparatus generally comprises a closed vessel for containing the
reaction mixture, a stirring system, a temperature control system
and a pressure control system. The pressure control system includes
a pressure sensor that communicates with the vessel, as well as a
flow sensor that monitors the flow rate of reactant entering the
vessel. Rates of consumption of the reactant can be determined from
the reactant flow rate and filling time.
[0017] The present invention also provides a method of making and
characterizing a plurality of materials. The method includes the
steps of providing vessels with starting materials to form reaction
mixtures, confining the reaction mixtures in the vessels to allow
the reaction to occur, and stirring the reaction mixtures for at
least a portion of the confining step. The method further includes
the step of evaluating the reaction mixtures by tracking at least
one characteristic of the reaction mixtures for at least a portion
of the confining step. Various characteristics or properties can be
monitored during the evaluating step, including temperature, rate
of heat transfer, conversion of starting materials, rate of
conversion, torque at a given stirring rate, stall frequency,
viscosity, molecular weight, specific gravity, elasticity,
dielectric constant, and conductivity.
[0018] One aspect of the present invention provides a method of
monitoring the rate of consumption of a gas-phase reactant. The
method comprises the steps of providing a vessel with starting
materials to form the reaction mixture, confining the reaction
mixtures in the vessel to allow reaction to occur, and stirring the
reaction mixture for at least a portion of the confining step. The
method further includes filling the vessel with the gas-phase
reactant until gas pressure in the vessel exceeds an upper-pressure
limit, P.sub.H, and allowing gas pressure in the vessel to decay
below a lower-pressure limit, P.sub.L. Gas pressure in the vessel
is monitored and recorded during the addition and consumption of
the reactant. This process is repeated at least once, and rates of
consumption of the gas-phase reactant in the reaction mixture are
determined from the pressure versus time record.
[0019] Another aspect of the present invention provides a method of
monitoring the rate of production of a gas-phase product. The
method comprises the steps of providing a vessel with starting
materials to form the reaction mixture, confining the reaction
mixtures in the vessel to allow reaction to occur, and stirring the
reaction mixture for at least a portion of the confining step. The
method also comprises the steps of allowing gas pressure in the
vessel to rise above an upper-pressure limit, P.sub.H, and venting
the vessel until gas pressure in the vessel falls below a
lower-pressure limit, P.sub.L. The gas pressure in the vessel is
monitored and recorded during the production of the gas-phase
component and subsequent venting of the vessel. The process is
repeated at least once, so rates of production of the gas-phase
product can be calculated from the pressure versus time record.
[0020] The present invention provides an apparatus for parallel
processing of reaction mixtures comprising vessels for containing
the reaction mixtures, a stirring system for agitating the reaction
mixtures, a temperature control system for regulating the
temperature of the reaction mixtures, and a fluid injection system.
The vessels are sealed to minimize unintentional gas flow into or
out of the vessels, and the fluid injection system allows
introduction of a liquid into the vessels at a pressure different
than ambient pressure. The fluid injection system includes fill
ports that are adapted to receive a liquid delivery probe, such as
a syringe or pipette, and also includes conduits, valves, and
tubular injectors. The conduits provide fluid communication between
the fill ports and the valves and between the valves and the
injectors. The injectors are located in the vessels, and can have
varying lengths, depending on whether fluid injection is to occur
in the reaction mixtures or in the vessel headspace above the
reaction mixtures. Generally, a robotic material handling system
manipulates the fluid delivery probe and controls the valves. The
injection system can be used to deliver gases, liquids, and
slurries, e.g., catalysts on solid supports.
[0021] One aspect of the present invention provides an apparatus
for parallel processing of reaction mixtures comprising sealed
vessels, a temperature control system, and a stirring system having
a magnetic feed through device for coupling an external drive
mechanism with a spindle that is completely contained within one of
the vessels. The magnetic feed through device includes a rigid
pressure barrier having a cylindrical interior surface that is open
along the base of the pressure barrier. The base of the pressure
barrier is attached to the vessel so that the interior surface of
the pressure barrier and the vessel define a closed chamber. The
magnetic feed through device further includes a magnetic driver
that is rotatably mounted on the rigid pressure barrier and a
magnetic follower that is rotatably mounted within the pressure
barrier. The drive mechanism is mechanically coupled to the
magnetic driver, and one end of the spindle is attached to a leg
portion of the magnetic follower that extends into the vessel
headspace. Since the magnetic driver and follower are magnetically
coupled, rotation of the magnetic driver induces rotation of the
magnetic follower and spindle.
[0022] Another aspect of the present invention provides an
apparatus for parallel processing of reaction mixtures comprising
sealed vessels, a temperature control system, and a stirring system
that includes multi-piece spindles that are partially contained in
the vessels. Each of the spindles includes an upper spindle portion
that is mechanically coupled to a drive mechanism, a removable
stirrer contained in one of the vessels, and a coupler for
reversibly attaching the removable stirrer to the upper spindle
portion. The removable stirrer is made of a chemically resistant
plastic material, such as polyethylethylketone or
polytetrafluoroethylene, and is typically discarded after use.
[0023] The exact combination of parallel processing features
depends on the embodiment of the invention being practiced. In some
aspects, the present invention provides an apparatus for parallel
processing of reaction mixtures comprising sealed vessels and an
injection system. The present invention also provides an apparatus
for parallel processing of reaction mixtures comprising sealed
vessels, an injection system and a stirring system. The present
invention also provides an apparatus for parallel processing of
reaction mixtures comprising vessels having a temperature control
system and a stirring system. The present invention also provides
an apparatus for parallel processing of reaction mixtures
comprising sealed vessels and a pressure control system. The
present invention also provides an apparatus for parallel
processing of reaction mixtures comprising sealed vessels, an
injection system and a system for property or characteristic
monitoring.
[0024] The present invention also provides computer programs and
computer-implemented methods for monitoring the progress and
properties of parallel chemical reactions. In one aspect, the
invention features a method of monitoring a combinatorial chemical
reaction. The method includes (a) receiving a measured value
associated with the contents of each of a plurality of reactor
vessels; (b) displaying the measured values; and (c) repeating
steps (a) and (b) multiple times over the course of the
combinatorial chemical reaction.
[0025] Implementations of the invention can include one or more of
the following advantageous features. The measured values include a
set of values for a number of reaction conditions associated with
each of the reactor vessels. Step (c) is performed at a
predetermined sampling rate. The method also includes changing a
reaction parameter associated with one of the reactor vessels in
response to the measured value to maintain the reactor vessel at a
predetermined set point. Reaction parameters include temperature,
pressure, and motor (stirring) speed. The method also includes
quenching a reaction in one of the reactor vessels in response to
the measured value associated with the contents of the reactor
vessel. The method also includes using the measured value to
calculate an experimental variable or value for one of the reactor
vessels. Examples of experimental variables include rates of change
of temperature or pressure, percent conversion of a starting
material, and viscosity. The method also includes displaying the
experimental variable.
[0026] In general, in another aspect, the invention features a
method for controlling a combinatorial chemical reactor including
multiple reactor vessels, each containing a reaction environment.
The method includes receiving a set point for a property associated
with each vessel's reaction environment; measuring a set of
experimental values for the property for each vessel; displaying
the set of experimental values; and changing the reaction
environment in one or more of the plurality of reactor vessels in
response to the set point and a change in one or more of the set of
experimental values. For example, the method may terminate a
reaction (change the reaction environment) in response to reactant
conversion (experimental value) indicating that a target conversion
(set point) has been reached. During reaction, a graphical
representation of the set of experimental values is displayed,
often as a histogram.
[0027] In general, in another aspect, the invention features a
computer program on a computer-readable medium for monitoring a
combinatorial chemical reaction. The program includes instructions
to (a) receive a measured value associated with the contents of
each of a plurality of reactor vessels, instructions to (b) display
the measured values, and instructions to (c) repeat steps (a) and
(b) multiple times during the course of the combinatorial chemical
reaction. The computer program includes instructions to change a
reaction parameter associated with one of the reactor vessels in
response to the measured value to maintain the reactor vessel at a
predetermined set point.
[0028] In general, in another aspect, the invention features a
reactor control system for monitoring and controlling parallel
chemical reactions. The reactor system includes a system control
module for providing control signals to a parallel chemical reactor
including multiple reactor vessels, a mixing monitoring and control
system, a temperature monitoring and control system, and a pressure
monitoring and control system. The reactor system also includes a
data analysis module for receiving a set of measured values from
the parallel chemical reactor and for calculating one or more
calculated values for each of the reactor vessels. In addition, the
reactor control system includes a user interface module for
receiving reaction parameters and for displaying the set of
measured values and calculated values.
[0029] Advantages that can be seen in implementations of the
invention include one or more of the following. Process variables
can be monitored and controlled for multiple elements in a
combinatorial library as a chemical reaction progresses. Data can
be extracted for each library element repeatedly and in parallel
over the course of the reaction, instead of extracting only a
limited number of data points for selected library elements.
Calculations and corrections can be applied automatically to every
available data point for every library element over the course of
the reaction. A single experimental value can be calculated from
the entire data set for each library element.
[0030] A further understanding of the nature and advantages of the
present invention may be realized by reference to the remaining
portions of the specification, drawings, and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 illustrates a parallel reactor system in accordance
with the present invention.
[0032] FIG. 2 shows a perspective view of a modular reactor block
with a robotic liquid handling system.
[0033] FIG. 3 shows a temperature monitoring system.
[0034] FIG. 4 shows a cross-sectional view of an integral
temperature sensor-vessel assembly.
[0035] FIG. 5 shows a side view of an infrared temperature
measurement system.
[0036] FIG. 6 shows a temperature monitoring and control system for
a reactor vessel.
[0037] FIG. 7 illustrates another temperature control system, which
includes liquid cooling and heating of the reactor block.
[0038] FIG. 8 is a cross-sectional view of thermoelectric devices
sandwiched between a reactor block and heat transfer plate.
[0039] FIG. 9 is a cross-sectional view of a portion of a reactor
block useful for obtaining calorimetric data.
[0040] FIG. 10 is an exploded perspective view of a stirring system
for a single module of a modular reactor block of the type shown in
FIG. 2.
[0041] FIG. 11 is a schematic representation of an electromagnetic
stirring system.
[0042] FIG. 12-13 are schematic representations of portions of
electromagnet stirring arrays in which the ratios of electromagnets
to vessel sites approach 1:1 and 2:1, respectively, as the number
of vessel sites becomes large.
[0043] FIG. 14 is a schematic representation of an electromagnet
stirring array in which the ratio of electromagnets to vessel sites
is 4:1.
[0044] FIG. 15 shows additional elements of an electromagnetic
stirring system, including drive circuit and processor.
[0045] FIG. 16 illustrates the magnetic field direction of a
2.times.2 electromagnet array at four different times during one
rotation of a magnetic stirring bar.
[0046] FIG. 17 illustrates the magnetic field direction of a
4.times.4 electromagnet array at five different times during one
full rotation of a 3.times.3 array of magnetic stirring bars.
[0047] FIG. 18 illustrates the rotation direction of the 3.times.3
array of magnetic stirring bars shown in FIG. 17.
[0048] FIG. 19 shows a wiring configuration for an electromagnetic
stirring system.
[0049] FIG. 20 shows an alternate wiring configuration for an
electromagnetic stirring system.
[0050] FIG. 21 shows the phase relationship between sinusoidal
source currents, I.sub.A(t) and I.sub.B(t), which drive two series
of electromagnets shown in FIG. 19 and 20.
[0051] FIG. 22 is a block diagram of a power supply for an
electromagnetic stirring system.
[0052] FIG. 23 illustrates an apparatus for directly measuring the
applied torque of a stirring system.
[0053] FIG. 24 shows placement of a strain gauge in a portion of a
base plate that is similar to the lower plate of the reactor module
shown in FIG. 10.
[0054] FIG. 25 shows an inductive sensing coil system for detecting
rotation and measuring phase angle of a magnetic stirring blade or
bar.
[0055] FIG. 26 shows typical outputs from inductive sensing coils,
which illustrate phase lag associated with magnetic stirring for
low and high viscosity solutions, respectively.
[0056] FIG. 27 illustrates how amplitude and phase angle will vary
during a reaction as the viscosity increases from a low value to a
value sufficient to stall the stirring bar.
[0057] FIG. 28-29 show bending modes of tuning forks and
bimorph/unimorph resonators, respectively.
[0058] FIG. 30 schematically shows a system for measuring the
properties of reaction mixtures using mechanical oscillators.
[0059] FIG. 31 shows an apparatus for assessing reaction kinetics
based on monitoring pressure changes due to production or
consumption various gases during reaction.
[0060] FIG. 32 shows results of calibration runs for
polystyrene-toluene solutions using mechanical oscillators.
[0061] FIG. 33 shows a calibration curve obtained by correlating
M.sub.w of the polystyrene standards with the distance between the
frequency response curve for toluene and each of the polystyrene
solutions of FIG. 32.
[0062] FIG. 34 depicts the pressure recorded during solution
polymerization of ethylene to polyethylene.
[0063] FIG. 35-36 show ethylene consumption rate as a function of
time, and the mass of polyethylene formed as a function of ethylene
consumed, respectively.
[0064] FIG. 37 shows a perspective view of an eight-vessel reactor
module, of the type shown in FIG. 10, which is fitted with an
optional liquid injection system.
[0065] FIG. 38 shows a cross sectional view of a first embodiment
of a fill port having an o-ring seal to minimize liquid leaks.
[0066] FIG. 39 shows a second embodiment of a fill port.
[0067] FIG. 40 shows a phantom front view of an injector
manifold.
[0068] FIG. 40A shows a perspective view of an injector manifold
1006
[0069] FIG. 40B shows a cross sectional view of the injector
manifold shown in FIG. 40A.
[0070] FIG. 41-42 show a cross sectional view of an injector
manifold along first and second section lines shown in FIG. 40,
respectively.
[0071] FIG. 43 shows a phantom top view of an injector adapter
plate, which serves as an interface between an injector manifold
and a block of a reactor module shown in FIG. 37.
[0072] FIG. 44 shows a cross sectional side view of an injector
adapter plate along a section line shown in FIG. 43.
[0073] FIG. 45 shows an embodiment of a well injector.
[0074] FIG. 46 shows a top view of a reactor module.
[0075] FIG. 47 shows a "closed" state of an injector system valve
prior to fluid injection.
[0076] FIG. 48 shows an "open" state of an injector system valve
prior during fluid injection, and shows a stirring mechanism and
associated seals for maintaining above-ambient pressure in reactor
vessels.
[0077] FIG. 49 shows a cross sectional view of a magnetic feed
through stirring mechanism that helps minimize gas leaks associated
with dynamic seals.
[0078] FIG. 50 shows a perspective view of a stirring mechanism
shown in FIG. 48, and provides details of a multi-piece
spindle.
[0079] FIG. 50A shows an alternative design for a multi-piece
spindle.
[0080] FIG. 50B shows details of the alternative design for a
multi-piece spindle shown in FIG. 50B.
[0081] FIG. 51 shows details of a coupler portion of a multi-piece
spindle.
[0082] FIG. 52 shows a cross sectional view of the coupler shown in
FIG. 51.
[0083] FIG. 53 is a block diagram of a data processing system
showing an implementation of the invention.
[0084] FIG. 54-57 are schematic diagrams of a parallel reactor
suitable for use with the invention.
[0085] FIG. 58 is a flow diagram of a method of controlling and
analyzing a parallel chemical reaction.
[0086] FIG. 59 is an illustration of a dialog window for user input
of system configuration information.
[0087] FIG. 60 is an illustration of a dialog window for user input
of data display information.
[0088] FIG. 61 is an illustration of a dialog window for user input
of parallel reactor parameters.
[0089] FIG. 62 is an illustration of a dialog window for user input
of a temperature gradient for reactor blocks in a parallel
reactor.
[0090] FIG. 63-64 are illustrations of windows displaying system
status and experimental results for a parallel reactor.
[0091] FIG. 65 is an illustration of a window displaying
experimental results for a single reactor vessel.
[0092] FIG. 66 is an illustration of a dialog window for user input
of color scaling parameters.
[0093] FIG. 67 is a schematic diagram of a computer platform
suitable for implementing the data processing system of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0094] The present invention provides an apparatus, methods, and
computer programs for carrying out and monitoring the progress and
properties of multiple reactions in situ. It is especially useful
for synthesizing, screening, and characterizing combinatorial
libraries, but offers significant advantages over conventional
experimental reactors as well. For example, in situ monitoring of
individual reaction mixtures not only provides feedback for process
controllers, but also provides data for determining reaction rates,
product yields, and various properties of the reaction products,
including viscosity and molecular weight during an experiment.
Moreover, in situ monitoring coupled with tight process control can
improve product selectivity, provide opportunities for process and
product optimization, allow processing of temperature-sensitive
materials, and decrease experimental variability.
[0095] Other advantages result from using small mixture volumes. In
addition to conserving valuable reactants, decreasing sample size
increases surface area relative to volume within individual reactor
vessels. This improves the uniformity of reaction mixtures, aids
gas-liquid exchange in multiphase reactions, and increases heat
transfer between the samples and the reactor vessels. Because large
samples respond much slower to changes in system conditions, the
use of small samples, along with in situ monitoring and process
control, also allows for time-dependent processing and
characterization.
[0096] The parallel reactor of this invention is useful for the
research and development of chemical reactions, catalysts and
processes. The same type of reaction may be preformed in each
vessel or different reactions may be performed in each vessel.
Thus, each reaction vessel may vary with regard to its contents
during an experiment. Each reaction vessel can vary by a process
condition, including catalyst amounts (volume, moles or mass),
ratios of starting components, time for reaction, reaction
temperature, reaction pressure, rate of reactant addition to the
reaction, reaction atmosphere, reaction stir rate, injection of a
catalyst or reactant or other component (e.g., a reaction quencher)
and other conditions that those of skill in the art will recognize.
Each reaction vessel can also vary by the chemicals present, such
as by using different reactants or catalysts in two or more
vessels.
[0097] For example, the parallel reactor of this invention may have
reaction vessels that are of different volume. The reactor vessel
volume may vary from about 0.1 milliliter (ml) to about 500 ml,
more particularly from about 1 ml to about 100 ml and even more
particularly from about 5 ml to about 20 ml. These reactor vessel
sizes allow for reactant volumes in a range that functionally allow
for proper stirring (e.g., a 15 ml reactor vessel allows for
reactant volumes of between about 2-10 ml). Also, the parallel
reactor of this invention allows the reactor pressure to vary from
vessel to vessel or module to module or cell to cell, with each
vessel being at a pressure in the range of from about atmospheric
pressure to about 500 psi and more particularly in the range of
from atmospheric to about 300 psi. In still other embodiments, the
reactor temperature may vary from vessel to vessel or module to
module or cell to cell, with each vessel being at a temperature in
the range of from about -150.degree. C. to about 250.degree. C. and
more particularly in the range of from -100.degree. C. to about
200.degree. C. The stirring rates may also vary from vessel to
vessel or module to module or cell to cell, with each vessel being
stirred by mechanical stirring at a rate of from about 0 to about
3000 revolutions per minute (rpm) and more particularly at a rate
of from about 10 to about 2000 rpm and even more particularly at a
rate of from about 100 to about 1000 rpm. In other embodiments, the
parallel reactor of this invention allows for the injection of
reactants or other components (such as catalysts) while a reactor
vessel is at reaction pressure (as discussed in detail below).
Generally, the injection of reactants or components allows for the
reaction conditions to be varied from vessel to vessel, such as by
adding a reaction quencher at a timed frequency or a conversion
frequency. Reaction times can vary depending on the experiment
being performed, but may be in the range from less than one minute
to about 48 hours, more particularly in the range of from about one
minute to about 24 hours and even more particularly in the range of
from about 5 minutes to about 12 hours.
[0098] Overview of Parallel Reactor
[0099] The parallel reactor system of the present invention is an
integrated platform for effecting combinatorial research in
chemistry and materials science applications. An integrated
parallel reactor system comprises a plurality of reactors that can
be operated in parallel on a scale suitable for research
applications--typically bench scale or smaller scale (e.g.,
mini-reactors and micro-reactors). The reactors of such an
integrated system can typically, but not necessarily, be formed in,
be integral with or be linked by a common substrate, be arranged in
a common plane, preferably with spatial uniformity, and/or can
share a common support structure or housing. The integrated
parallel reactor system can also include one or more control and
monitoring systems that are fully or partially integral
therewith.
[0100] FIG. 1 shows one embodiment of a parallel reactor system
100. The reactor system 100 includes removable vessels 102 for
receiving reactants. Wells 104 formed into a reactor block 106
contain the vessels 102. Although the wells 104 can serve as
reactor vessels, removable vessels 102 or liners provide several
advantages. For example, following reaction and preliminary testing
(screening), one can remove a subset of vessels 102 from the
reactor block 106 for further in-depth characterization. When using
removable vessels 102, one can also select vessels 102 made of
material appropriate for a given set of reactants, products, and
reaction conditions. Unlike the reactor block 106, which represents
a significant investment, the vessels 102 can be discarded if
damaged after use. Finally, one can lower system 100 costs and
ensure compatibility with standardized sample preparation and
testing equipment by designing the reactor block 106 to accommodate
commercially available vessels.
[0101] As shown in FIG. 1, each of the vessels 102 contains a
stirring blade 108. In one embodiment, each stirring blade 108
rotates at about the same speed, so that each of the reaction
mixtures within the vessels 102 experience similar mixing. Because
reaction products can be influenced by mixing intensity, a uniform
rotation rate ensures that any differences in products does not
result from mixing variations. In another embodiment, the rotation
rate of each stirring blade 108 can be varied independently, which
as discussed below, can be used to characterize the viscosity and
molecular weight of the reaction products or can be used to study
the influence of mixing speed on reaction.
[0102] Depending on the nature of the starting materials, the types
of reactions, and the method used to characterize reaction products
and rates of reaction, it may be desirable to enclose the reactor
block 106 in a chamber 110. The chamber 110 may be evacuated or
filled with a suitable gas. In some cases, the chamber 110 may be
used only during the loading of starting materials into the vessels
102 to minimize contamination during sample preparation, for
example, to prevent poisoning of oxygen sensitive catalysts. In
other cases, the chamber 110 may be used during the reaction
process or the characterization phase, providing a convenient
method of supplying one or more gases to all of the vessels 102
simultaneously. In this way, a gaseous reactant can be added to all
of the vessels 102 at one time. Note, however, it is often
necessary to monitor the rate of disappearance of a gaseous
reactant--for example, when determining rates of conversion--and in
such cases the vessels 102 are each sealed and individually
connected to a gas source, as discussed below.
[0103] FIG. 2 shows a perspective view of a parallel reactor system
130 comprised of a modular reactor block 132. The modular reactor
block 132 shown in FIG. 2 consists of six modules 134, and each
module 134 contains eight vessels (not shown). Note, however, the
number of modules 134 and the number of vessels within each of the
modules 134 can vary. In some embodiments, a module 134 may be
broken down into component cells (not shown), for example with each
cell containing one well 104 holding a reaction vessel 102. Thus,
if a module is to contain eight reaction vessels, there may be
eight cells, which facilitates lower cost manufacturing as well as
replacement of damaged or worn cells. There may any number of cells
per module, such as cell that contains two reaction vessels per
cell, etc.
[0104] The use of modules 134 offers several advantages over a
monolithic reactor block. For example, the size of the reactor
block 132 can be easily adjusted depending on the number of
reactants or the size of the combinatorial library. Also,
relatively small modules 134 are easier to handle, transport, and
fabricate than a single, large reactor block. A damaged module can
be quickly replaced by a spare module, which minimizes repair costs
and downtime. Finally, the use of modules 134 improves control over
reaction parameters. For instance, stirring speed, temperature, and
pressure of each of the vessels can be varied between modules.
[0105] In the embodiment shown in FIG. 2, each of the modules 134
is mounted on a base plate 136 having a front 138 and a rear 140.
The modules 134 are coupled to the base plate 136 using guides (not
shown) that mate with channels 142 located on the surface of the
base plate 136. The guides prevent lateral movement of the modules
134, but allow linear travel along the channels 142 that extend
from the front 138 toward the rear 140 of the base plate 136. Stops
144 located in the channels 142 near the front 138 of the base
plate 136 limit the travel of the modules 134. Thus, one or more of
the modules 134 can be moved towards the front 138 of the base
plate 136 to gain access to individual vessels while the other
modules 134 undergo robotic filling. In another embodiment, the
modules 134 are rigidly mounted to the base plate 136 using bolts,
clips, or other fasteners.
[0106] As illustrated in FIG. 2, a conventional robotic material
handling system 146 is ordinarily used to load vessels with
starting materials. The robotic system 146 includes a pipette or
probe 148 that dispenses measured amounts of liquids into each of
the vessels. The robotic system 146 manipulates the probe 148 using
a 3-axis translation system 150. The probe 148 is connected to
sources 152 of liquid reagents through flexible tubing 154. Pumps
156, which are located along the flexible tubing 154, are used to
transfer liquid reagents from the sources 152 to the probe 148.
Suitable pumps 156 include peristaltic pumps and syringe pumps. A
multi-port valve 158 located downstream of the pumps 156 selects
which liquid reagent from the sources 152 is sent to the probe 148
for dispensing in the vessels.
[0107] The robotic fluid handling system 146 is controlled by a
processor 160. In the embodiment shown in FIG. 2, the user first
supplies the processor 160 with operating parameters using a
software interface. Typical operating parameters include the
coordinates of each of the vessels and the initial compositions of
the reaction mixtures in individual vessels. The initial
compositions can be specified as lists of liquid reagents from each
of the sources 152, or as incremental additions of various liquid
reagents relative to particular vessels.
Temperature Control and Monitoring
[0108] The ability to monitor and control the temperature of
individual reactor vessels is an important aspect of the present
invention. During synthesis, temperature can have a profound effect
on structure and properties of reaction products. For example, in
the synthesis of organic molecules, yield and selectivity often
depend strongly on temperature. Similarly, in polymerization
reactions, polymer structure and properties--molecular weight,
particle size, monomer conversion, microstructure--can be
influenced by reaction temperature. During screening or
characterization of combinatorial libraries, temperature control
and monitoring of library members is often essential to making
meaningful comparisons among members. Finally, temperature can be
used as a screening criteria or can be used to calculate useful
process and product variables. For instance, catalysts of
exothermic reactions can be ranked based on peak reaction
temperature and/or total heat released over the course of reaction,
and temperature measurements can be used to compute rates of
reaction and conversion.
[0109] FIG. 3 illustrates one embodiment of a temperature
monitoring system 180, which includes temperature sensors 182 that
are in thermal contact with individual vessels 102. For clarity, we
describe the temperature monitoring system 180 with reference to
the monolithic reactor block 106 of FIG. 1, but this disclosure
applies equally well to the modular reactor block 132 of FIG. 2.
Suitable temperature sensors 182 include jacketed or non-jacketed
thermocouples (TC), resistance thermometric devices (RTD), and
thermistors. The temperature sensors 182 communicate with a
temperature monitor 184, which converts signals received from the
temperature sensors 182 to a standard temperature scale. An
optional processor 186 receives temperature data from the
temperature monitor 184. The processor 186 performs calculations on
the data, which may include wall corrections and simple comparisons
between different vessels 102, as well as more involved processing
such as calorimetry calculations discussed below. During an
experimental run, temperature data is typically sent to storage 188
so that it can be retrieved at a later time for analysis.
[0110] FIG. 4 shows a cross-sectional view of an integral
temperature sensor-vessel assembly 200. The temperature sensor 202
is embedded in the wall 204 of a reactor vessel 206. The surface
208 of the temperature sensor 202 is located adjacent to the inner
wall 210 of the vessel to ensure good thermal contact between the
contents of the vessel 206 and the temperature sensor 202. The
sensor arrangement shown in FIG. 3 is useful when it is necessary
to keep the contents of the reactor vessel 206 free of
obstructions. Such a need might arise, for example, when using a
freestanding mixing device, such as a magnetic stirring bar. Note,
however, that fabricating an integral temperature sensor such as
the one shown in FIG. 4 can be expensive and time consuming,
especially when using glass reactor vessels.
[0111] Thus, in another embodiment, the temperature sensor is
immersed in the reaction mixture. Because the reaction environment
within the vessel may rapidly damage the temperature sensor, it is
usually jacketed with an inert material, such as a fluorinated
thermoplastic. In addition to low cost, direct immersion offers
other advantages, including rapid response and improved accuracy.
In still another embodiment, the temperature sensor is placed on
the outer surface 212 of the reactor vessel of FIG. 4. As long as
the thermal conductivity of the reactor vessel is known, relatively
accurate and rapid temperature measurements can be made.
[0112] One can also remotely monitor temperature using an infrared
system illustrated in FIG. 5. The infrared monitoring system 230
comprises an optional isolation chamber 232, which contains the
reactor block 234 and vessels 236. The top 238 of the chamber 232
is fitted with a window 240 that is transparent to infrared
radiation. An infrared-sensitive camera 242 positioned outside the
isolation chamber 232, detects and records the intensity of
infrared radiation passing through the window 240. Since infrared
emission intensity depends on source temperature, it can be used to
distinguish high temperature vessels from low temperature vessels.
With suitable calibration, infrared intensity can be converted to
temperature, so that at any given time, the camera 242 provides
"snapshots" of temperature along the surface 244 of the reactor
block 234. In the embodiment shown in FIG. 5, the tops 246 of the
vessels 236 are open. In an alternate embodiment, the tops 246 of
the vessels 236 are fitted with infrared transparent caps (not
shown). Note that, with stirring, the temperature is uniform within
a particular vessel, and therefore the surface temperature of the
vessel measured by infrared emission will agree with the bulk
temperature measured by a TC or RTD immersed in the vessel.
[0113] The temperature of the reactor vessels and block can be
controlled as well as monitored. Depending on the application, each
of the vessels can be maintained at the same temperature or at
different temperatures during an experiment. For example, one may
screen compounds for catalytic activity by first combining, in
separate vessels, each of the compounds with common starting
materials; these mixtures are then allowed to react at uniform
temperature. One may then further characterize a promising catalyst
by combining it in numerous vessels with the same starting
materials used in the screening step. The mixtures then react at
different temperatures to gauge the influence of temperature on
catalyst performance (speed, selectivity). In many instances, it
may be necessary to change the temperature of the vessels during
processing. For example, one may decrease the temperature of a
mixture undergoing a reversible exothermic reaction to maximize
conversion. Or, during a characterization step, one may ramp the
temperature of a reaction product to detect phase transitions
(melting range, glass transition temperature). Finally, one may
maintain the reactor block at a constant temperature, while
monitoring temperature changes in the vessels during reaction to
obtain calorimetric data as described below.
[0114] FIG. 6 shows a useful temperature control system 260, which
comprises separate heating 262 and temperature sensing 264
elements. The heating element 262 shown in FIG. 6 is a conventional
thin filament resistance heater whose heat output is proportional
to the product of the filament resistance and the square of the
current passing through the filament. The heating element 262 is
shown coiled around a reactor vessel 266 to ensure uniform radial
and axial heating of the vessel 266 contents. The temperature
sensing element 264 can be a TC, RTD, and the like. The heating
element 262 communicates with a processor 268, which based on
information received from the temperature sensor 264 through a
temperature monitoring system 270, increases or decreases heat
output of the heating element 262. A heater control system 272,
located in the communication path between the heating element 262
and the processor 268, converts a processor 268 signal for an
increase (decrease) in heating into an increase (decrease) in
electrical current through the heating element 262. Generally, each
of the vessels 104 of the parallel reactor system 100 shown in FIG.
1 or FIG. 3 are equipped with a heating element 262 and one or more
temperature sensors 264, which communicate with a central heater
control system 272, temperature monitoring system 270, and
processor 268, so that the temperature of the vessels 104 can be
controlled independently.
[0115] Other embodiments include placing the heating element 262
and temperature sensor 264 within the vessel 266, which results in
more accurate temperature monitoring and control of the vessel 266
contents, and combining the temperature sensor and heating element
in a single package. A thermistor is an example of a combined
temperature sensor and heater, which can be used for both
temperature monitoring and control because its resistance depends
on temperature.
[0116] FIG. 7 illustrates another temperature control system, which
includes liquid cooling and heating of the reactor block 106.
Regulating the temperature of the reactor block 106 provides many
advantages. For example, it is a simple way of maintaining nearly
uniform temperature in all of the reactor vessels 102. Because of
the large surface area of the vessels 102 relative to the volume of
the reaction mixture, cooling the reactor block 106 also allows one
to carryout highly exothermic reactions. When accompanied by
temperature control of individual vessels 102, active cooling of
the reactor block 106 allows for processing at sub-ambient
temperatures. Moreover, active heating or cooling of the reactor
block 106 combined with temperature control of individual vessels
102 or groups of vessels 102 also decreases response time of the
temperature control feedback. One may control the temperature of
individual vessels 102 or groups of vessels 102 using compact heat
transfer devices, which include electric resistance heating
elements or thermoelectric devices, as shown in FIG. 6 and FIG. 8,
respectively. Although we describe reactor block cooling with
reference to the monolithic reactor block 106, one may, in a like
manner, independently heat or cool individual modules 134 of the
modular reactor block 132 shown in FIG. 2.
[0117] Returning to FIG. 7, a thermal fluid 290, such as water,
steam, a silicone fluid, a fluorocarbon, and the like, is
transported from a uniform temperature reservoir 292 to the reactor
block 106 using a constant or variable speed pump 294. The thermal
fluid 290 enters the reactor block 106 from a pump outlet conduit
296 through an inlet port 298. From the inlet port 298, the thermal
fluid 290 flows through a passageway 300 formed in the reactor
block 106. The passageway may comprise single or multiple channels.
The passageway 300 shown in FIG. 7, consists of a single channel
that winds its way between rows of vessels 102, eventually exiting
the reactor block 106 at an outlet port 302. The thermal fluid 290
returns to the reservoir 292 through a reactor block outlet conduit
304. A heat pump 306 regulates the temperature of the thermal fluid
290 in the reservoir 292 by adding or removing heat through a heat
transfer coil 308. In response to signals from temperature sensors
(not shown) located in the reactor block 106 and the reservoir 292,
a processor 310 adjusts the amount of heat added to or removed from
the thermal fluid 290 through the coil 308. To adjust the flow rate
of thermal fluid 290 through the passageway 300, the processor 310
communicates with a valve 312 located in a reservoir outlet conduit
314. The reactor block 106, reservoir 292, pump 294, and conduits
296, 304, 314 can be insulated to improve temperature control in
the reactor block 106.
[0118] Because the reactor block 106 is typically made of a metal
or other material possessing high thermal conductivity, the single
channel passageway 300 is usually sufficient for maintaining the
temperature of the block 106 a few degrees above or below room
temperature. To improve temperature uniformity within the reactor
block 106, the passageway can be split into parallel channels (not
shown) immediately downstream of the inlet port 298. In contrast to
the single channel passageway 300 depicted in FIG. 7, each of the
parallel channels passes between a single row of vessels 102 before
exiting the reactor block 106. This parallel flow arrangement
decreases the temperature gradient between the inlet 298 and outlet
302 ports. To further improve temperature uniformity and heat
exchange between the vessels 102 and the block 106, the passageway
300 can be enlarged so that the wells 104 essentially project into
a cavity containing the thermal fluid 290. Additionally, one may
eliminate the reactor block 106 entirely, and suspend or immerse
the vessels 102 in a bath containing the thermal fluid 290.
[0119] FIG. 8 illustrates the use of thermoelectric devices for
heating and cooling individual vessels. Thermoelectric devices can
function as both heaters and coolers by reversing the current flow
through the device. Unlike resistive heaters, which convert
electric power to heat, thermoelectric devices are heat pumps that
exploit the Peltier effect to transfer heat from one face of the
device to the other. A typical thermoelectric assembly has the
appearance of a sandwich, in which the front face of the
thermoelectric device is in thermal contact with the object to be
cooled (heated), and the back face of the device is in thermal
contact with a heat sink (source). When the heat sink or source is
ambient air, the back face of the device typically has an array of
thermally conductive fins to increase the heat transfer area.
Preferably, the heat sink or source is a liquid. Compared to air,
liquids have higher thermal conductivity and heat capacity, and
therefore should provide better heat transfer through the back face
of the device. But, because thermoelectric devices are usually made
with bare metal connections, they often must be physically isolated
from the liquid heat sink or source.
[0120] For example, FIG. 8 illustrates one way of using
thermoelectric devices 330 to heat and cool reactor vessels 338
using a liquid heat sink or source. In the configuration shown in
FIG. 8, thermoelectric devices 330 are sandwiched between a reactor
block 334 and a heat transfer plate 336. Reactor vessels 338 sit
within wells 340 formed in the reactor block 334. Thin walls 342 at
the bottom of the wells 340, separate the vessels 338 from the
thermoelectric devices 330, ensuring good thermal contact. As shown
in FIG. 8, each of the vessels 338 thermally contacts a single
thermoelectric device 330, although in general, a thermoelectric
device can heat or cool more than one of the vessels 338. The
thermoelectric devices 330 either obtain heat from, or dump heat
into, a thermal fluid that circulates through an interior cavity
344 of the heat transfer plate 336. The thermal fluid enters and
leaves the heat transfer plate 336 through inlet 346 and outlet 348
ports, and its temperature is controlled in a manner similar to
that shown in FIG. 7. During an experiment, the temperature of the
thermal fluid is typically held constant, while the temperature of
the vessels 338 is controlled by adjusting the electrical current,
and hence, the heat transport through the thermoelectric devices
330. Though not shown in FIG. 8, the temperature of the vessels 338
are controlled in a manner similar to the scheme depicted in FIG.
6. Temperature sensors located adjacent to the vessels 338 and
within the heat transfer plate cavity 344 communicate with a
processor via a temperature monitor. In response to temperature
data from the temperature monitor, the processor increases or
decrease heat flow to or from the thermoelectric devices 330. A
thermoelectric device control system, located in the communication
path between the thermoelectric devices 330 and the processor,
adjusts the magnitude and direction of the flow of electrical
current through each of the thermoelectric devices 330 in response
to signals from the processor.
Calorimetric Data Measurement and Use
[0121] Temperature measurements often provide a qualitative picture
of reaction kinetics and conversion and therefore can be used to
screen library members. For example, rates of change of temperature
with respect to time, as well as peak temperatures reached within
each of the vessels can be used to rank catalysts. Typically, the
best catalysts of an exothermic reaction are those that, when
combined with a set of reactants, result in the greatest heat
production in the shortest amount of time.
[0122] In addition to its use as a screening tool, temperature
measurement--combined with proper thermal management and design of
the reactor system--can also be used to obtain quantitative
calorimetric data. From such data, scientists can, for example,
compute instantaneous conversion and reaction rate, locate phase
transitions (melting point, glass transition temperature) of
reaction products, or measure latent heats to deduce structural
information of polymeric materials, including degree of
crystallinity and branching.
[0123] FIG. 9 shows a cross-sectional view of a portion of a
reactor block 360 that can be used to obtain accurate calorimetric
data. Each of the vessels 362 contain stirring blades 364 to ensure
that the contents 366 of the vessels 362 are well mixed and that
the temperature within any one of the vessels 362, T.sub.j, is
uniform. Each of the vessels 362 contains a thermistor 368, which
measures T.sub.j and heats the vessel contents 366. The walls 370
of the vessels 362 are made of glass, although one may use any
material having relatively low thermal conductivity, and similar
mechanical strength and chemical resistance. The vessels 362 are
held within wells 372 formed in the reactor block 360, and each of
the wells 372 is lined with an insulating material 374 to further
decrease heat transfer to or from the vessels 362. Useful
insulating materials 374 include glass wool, silicone rubber, and
the like. The insulating material 374 can be eliminated or replaced
by a thermal paste when better thermal contact between that reactor
block 360 and the vessels 362 is desired--good thermal contact is
needed, for example, when investigating exothermic reactions under
isothermal conditions. The reactor block 360 is made of a material
having high thermal conductivity, such as aluminum, stainless
steel, brass, and so on. High thermal conductivity, accompanied by
active heating or cooling using any of the methods described above,
help maintain uniform temperature, T.sub.o, throughout the reactor
block 360. One can account for non-uniform temperatures within the
reactor block 360 by measuring T.sub.oj, the temperature of the
block 360 in the vicinity of each of the vessels 362, using block
temperature sensors 376. In such cases, T.sub.oj, instead of
T.sub.o, is used in the calorimetric calculations described
next.
[0124] An energy balance around the contents 366 of one of the
vessels 362 (jth vessel) yields an expression for fractional
conversion, X.sub.j, of a key reactant at any time, t, assuming
that the heat of reaction, .DELTA.H.sub.rjand the specific heat of
the vessel contents 366, C.sub.P,j, are known and are constant over
the temperature range of interest: 1. .times. .times. M j .times. c
P , j .times. d T j d t = m o , j .times. .DELTA. .times. .times. H
r , j .times. d X j d t + Q i .times. .times. n , j - Q out , j I
##EQU1##
[0125] In expression I, M.sub.j is the mass of the contents 366 of
the jth vessel; m.sub.o,jis the initial mass of the key reactant;
Q.sub.in,j is the rate of heat transfer into the jth vessel by
processes other than reaction, as for example, by resistance
heating of the thermistor 368. Q.sub.out,j is the rate of heat
transfer out of the jth vessel, which can be determined from the
expression: 2.
Q.sub.out,j=U.sub.jA.sub.j(T.sub.j-T.sub.o)=U.sub.jA.sub.j.DELTA.T.sub.j
II
[0126] where A.sub.j is the heat transfer area--the surface area of
the jth vessel--and U.sub.j is the heat transfer coefficient, which
depends on the properties of the vessel 362 and its contents 366,
as well as the stirring rate. U.sub.j can be determined by
measuring the temperature rise, .DELTA.T.sub.j, in response to a
known heat input.
[0127] Equations I and II can be used to determine conversion from
calorimetric data in at least two ways. In a first method, the
temperature of the reactor block 360 is held constant, and
sufficient heat is added to each of the vessels 362 through the
thermistor 368 to maintain a constant value of .DELTA.T.sub.j.
Under such conditions, and after combining equations I and II, the
conversion can be calculated from the expression 3. .times. .times.
X j = 1 m o , j .times. .DELTA. .times. .times. H r , j .times. ( U
j .times. A j .times. t f .times. .DELTA. .times. .times. T j -
.intg. 0 t f .times. Q i .times. .times. n , j .times. d t ) , III
##EQU2##
[0128] where the integral can be determined by numerically
integrating the power consumption of the thermistor 368 over the
length of the experiment, t.sub.f. This method can be used to
measure the heat output of a reaction under isothermal
conditions.
[0129] In a second method, the temperature of the reactor block 360
is again held constant, but T.sub.j increases or decreases in
response to heat produced or consumed in the reaction. Equation I
and II become under such circumstances 4. .times. .times. X j = 1 m
o , j .times. .DELTA. .times. .times. H r , j .times. ( M j .times.
c P , j .function. ( T f , j - T i , j ) + U j .times. A j .times.
.intg. 0 t f .times. .DELTA. .times. .times. T j .times. d t ) . IV
##EQU3##
[0130] In equation IV, the integral can be determined numerically,
and T.sub.f,j and T.sub.i,j are temperatures of the reaction
mixture within the jth vessel at the beginning and end of reaction,
respectively. Thus, if T.sub.i,j equals T.sub.i,j, the total heat
liberated is proportional to .intg. 0 t f .times. .DELTA. .times.
.times. T j .times. d t . ##EQU4## This method is simpler to
implement than the isothermal method since it does not require
temperature control of individual vessels. But, it can be used only
when the temperature change in each of the reaction vessels 362 due
to reaction does not significantly influence the reaction under
study.
[0131] One may also calculate the instantaneous rate of
disappearance of the key reactant in the jth vessel, -r.sub.j,
using equation I, III or IV since -r.sub.j is related to conversion
through the relationship 5. .times. - r j = C o , j .times. d X j d
t , V ##EQU5##
[0132] which is valid for constant volume reactions. The constant
C.sub.o,j is the initial concentration of the key reactant.
Stirring Systems
[0133] Mixing variables such as stirring blade torque, rotation
rate, and geometry, may influence the course of a reaction and
therefore affect the properties of the reaction products. For
example, the overall heat transfer coefficient and the rate of
viscous dissipation within the reaction mixture may depend on the
stirring blade rate of rotation. Thus, in many instances it is
important that one monitor and control the rate of stirring of each
reaction mixture to ensure uniform mixing. Alternatively, the
applied torque may be monitored in order to measure the viscosity
of the reaction mixture. As described in the next section,
measurements of solution viscosity can be used to calculate the
average molecular weight of polymeric reaction products.
[0134] FIG. 10 shows an exploded, perspective view of a stirring
system for a single module 390 of a modular reactor block of the
type shown in FIG. 2. The module 390 comprises a block 392 having
eight wells 394 for containing removable reaction vessels 396. The
number of wells 394 and reaction vessels 396 can vary. The top
surface 398 of a removable lower plate 400 serves as the base for
each of the wells 394 and permits removal of the reaction vessels
396 through the bottom 402 of the block 392. Screws 404 secure the
lower plate 400 to the bottom 402 of the block 392. An upper plate
406, which rests on the top 408 of the block 392, supports and
directs elongated stirrers 410 into the interior of the vessels
396. Each of the stirrers 410 comprises a spindle 412 and a
rotatable stirring member or stirring blade 414 which is attached
to the lower end of each spindle 412. A gear 416 is attached to the
upper end of each of each spindle 412. When assembled, each gear
416 meshes with an adjacent gear 416 forming a gear train (not
shown) so that each stirrer 410 rotates at the same speed. A DC
stepper motor 418 provides torque for rotating the stirrers 410,
although an air-driven motor, a constant-speed AC motor, or a
variable-speed AC motor can be used instead. A pair of driver gears
420 couple the motor 418 to the gear train. A removable cover 422
provides access to the gear train, which is secured to the block
392 using threaded fasteners 424. In addition to the gear train,
one may employ belts, chains and sprockets, or other drive
mechanisms. In alternate embodiments, each of the stirrers 410 are
coupled to separate motors so that the speed or torque of each of
the stirrers 410 can be independently varied and monitored.
Furthermore, the drive mechanism--whether employing a single motor
and gear train or individual motors--can be mounted below the
vessels 362. In such cases, magnetic stirring blades placed in the
vessels 362 are coupled to the drive mechanism using permanent
magnets attached to gear train spindles or motor shafts.
[0135] In addition to the stirring system, other elements shown in
FIG. 10 merit discussion. For example, the upper plate 406 may
contain vessel seals 426 that allow processing at pressures
different than atmospheric pressure. Moreover, the seals 426 permit
one to monitor pressure in the vessels 396 over time. As discussed
below, such information can be used to calculate conversion of a
gaseous reactant to a condensed species. Note that each spindle 412
may penetrate the seals 426, or may be magnetically coupled to an
upper spindle member (not shown) attached to the gear 416. FIG. 10
also shows temperature sensors 428 embedded in the block 392
adjacent to each of the wells 394. The sensors 428 are part of the
temperature monitoring and control system described previously.
[0136] In another embodiment, an array of electromagnets rotate
freestanding stirring members or magnetic stirring bars, which
obviates the need for the mechanical drive system shown in FIG. 10.
Electromagnets are electrical conductors that produce a magnetic
field when an electric current passes through them. Typically, the
electrical conductor is a wire coil wrapped around a solid core
made of material having relatively high permeability, such as soft
iron or mild steel.
[0137] FIG. 11 is a schematic representation of one embodiment of
an electromagnet stirring array 440. The electromagnets 442 or
coils belonging to the array 440 are mounted in the lower plate 400
of the reactor module 390 of FIG. 10 so that their axes are about
parallel to the centerlines of the vessels 396. Although greater
magnetic field strength can be achieved by mounting the
electromagnets with their axes perpendicular to the centerlines of
the vessels 396, such a design is more difficult to implement since
it requires placing electromagnets between the vessels 396. The
eight crosses or vessel sites 444 in FIG. 11 mark the approximate
locations of the respective centers of each of the vessels 396 of
FIG. 10 and denote the approximate position of the rotation axes of
the magnetic stirring bars (not shown). In the array 440 shown in
FIG. 11, four electromagnets 442 surround each vessel site 444,
though one may use fewer or greater numbers of electromagnets 442.
The minimum number of electromagnets per vessel site is two, but in
such a system it is difficult to initiate stirring, and it is
common to stall the stirring bar. Electromagnet size and available
packing density primarily limit the maximum number of
electromagnets.
[0138] As illustrated in FIG. 11, each vessel site 444, except
those at the ends 446 of the array 440, shares its four
electromagnets 442 with two adjacent vessel sites. Because of this
sharing, magnetic stirring bars at adjacent vessel sites rotate in
opposite directions, as indicated by the curved arrows 448 in FIG.
11, which may lead to stalling. Other array configurations are
possible. For example, FIG. 12 shows a portion of an array 460 in
which the ratio of electromagnets 462 to vessel sites 464
approaches 1:1 as the number of vessel sites 464 becomes large.
Because each of the vessel sites 464 shares its electromagnets 462
with its neighbors, magnetic stirring bars at adjacent vessel sites
rotate in opposite directions, as shown by curved arrows 466. In
contrast, FIG. 13 shows a portion of an array 470 in which the
ratio of electromagnets 472 to vessel sites 474 approaches 2:1 as
the number of vessel sites becomes large. Because of the
comparatively large number of electromagnets 472 to vessel sites
474, all of the magnetic stirring bars can be made to rotate in the
same direction 476, which minimizes stalling. Similarly, FIG. 14
shows an array 480 in which the number of electromagnets 482 to
vessel sites 484 is 4:1. Each magnetic stirring bar rotates in the
same direction 486.
[0139] FIG. 15 illustrates additional elements of an
electromagnetic stirring system 500. For clarity, FIG. 15 shows a
square electromagnet array 502 comprised of four electromagnets
504, although larger arrays, such as those shown in FIG. 12-14, can
be used. Each of the electromagnets 504 comprises a wire 506
wrapped around a high permeability solid core 508. The pairs of
electromagnets 504 located on the two diagonals of the square array
502 are connected in series to form a first circuit 510 and a
second circuit 512. The first 510 and second 512 circuits are
connected to a drive circuit 514, which is controlled by a
processor 516. Electrical current, whether pulsed or sinusoidal,
can be varied independently in the two circuits 510, 512 by the
drive circuit 514 and processor 516. Note that within each circuit
510, 512, the current flows in opposite directions in the wire 506
around the core 508. In this way, each of the electromagnets 504
within a particular circuit 510, 512 have opposite magnetic
polarities. The axes 518 of the electromagnets 504 are about
parallel to the centerline 520 of the reactor vessel 522. A
magnetic stirring bar 524 rests on the bottom of the vessel 522
prior to operation. Although the electromagnets 504 can also be
oriented with their axes 518 perpendicular to the vessel centerline
520, the parallel alignment provides higher packing density.
[0140] FIG. 16 shows the magnetic field direction of a 2.times.2
electromagnet array at four different times during one full
rotation of the magnetic stirring bar 524 of FIG. 15, which is
rotating at a steady frequency of .omega. radianss.sup.-1. In FIG.
16, a circle with a plus sign 532 indicates that the electromagnet
produces a magnetic field in a first direction; a circle with a
minus sign 534 indicates that the electromagnet produces a magnetic
field in a direction opposite to the first direction; and a circle
with no sign 536 indicates that the electromagnet produces no
magnetic field. At time t=0, the electromagnets 530 produce an
overall magnetic field with a direction represented by a first
arrow 538 at the vessel site. At time t=.pi./2.omega., the
electromagnets 540 produce an overall magnetic field with a
direction represented by a second arrow 542. Since the magnetic
stirring bar 524 (FIG. 15) attempts to align itself with the
direction of the overall magnetic field, it rotates clockwise
ninety degrees from the first direction 538 to the second direction
542. At time t=.pi./.omega., the electromagnets 544 produce an
overall magnetic field with a direction represented by a third
arrow 546. Again, the magnetic stirring bar 524 aligns itself with
the direction of the overall magnetic field, and rotates clockwise
an additional ninety degrees. At time t=3.pi./2.omega., the
electromagnets 548 produce an overall magnetic field with a
direction represented by a fourth arrow 550, which rotates the
magnetic stirring bar 524 clockwise another ninety degrees.
Finally, at time t = 2 .times. .pi. .omega. , ##EQU6## the
electromagnets 530 produce an overall magnetic field with direction
represented by the first arrow 538, which rotates the magnetic
stirring bar 524 back to its position at time t=0.
[0141] FIG. 17 illustrates magnetic field direction of a 4.times.4
electromagnetic array at five different times during one full
rotation of a 3.times.3 array of magnetic stirring bars. As in FIG.
15, a circle with a plus sign 570, a minus sign 572, or no sign 574
represents the magnetic field direction of an individual
electromagnet, while an arrow 576 represents the direction of the
overall magnetic field at a vessel site. As shown, sixteen
electromagnets are needed to rotate nine magnetic stirring bars.
But, as indicated in FIG. 18, due to sharing of electromagnets by
multiple magnetic stirring bars, the rotational direction of the
magnetic fields is non-uniform. Thus, five of the fields rotate in
a clockwise direction 590 while the remaining four fields rotate in
a counter-clockwise direction 592.
[0142] FIG. 19 and FIG. 20 illustrate wiring configurations for
electromagnet arrays in which each vessel site is located between
four electromagnets defining four corners of a quadrilateral
sub-array. For each vessel site, both wiring configurations result
in an electrical connection between electromagnets located on the
diagonals of a given sub-array. In the wiring configuration 610
shown in FIG. 19, electromagnets 612 in alternating diagonal rows
are wired together to form two series of electromagnets 612. Dashed
and solid lines represent electrical connections between
electromagnets 612 in a first series 614 and a second series 616,
respectively. Plus signs 618 and minus signs 620 indicate polarity
(magnetic field direction) of individual electromagnets 612 at any
time, t, when current in the first series 614 and the second series
616 of electromagnets 612 are in phase. FIG. 20 illustrates an
alternate wiring configuration 630 of electromagnets 632, where
again, dashed and solid lines represent electrical connections
between the first 634 and second series 636 of electromagnets 632,
and plus signs 638 and minus signs 640 indicate magnetic
polarity.
[0143] Note that for both wiring configurations 610, 630, the
polarities of the electromagnets 612, 632 of the first series 614,
634 are not the same, though amplitudes of the current passing
through the connections between the electromagnets 612, 632 of the
first series 614, 634 are equivalent. The same is true for the
second series 616, 636 of electromagnets 612, 632. One can achieve
opposite polarities within the first series 614, 634 or second
series 616, 636 of electromagnets 612, 632 by reversing the
direction of electrical current around the core of the
electromagnet 612, 632. See, for example, FIG. 15. In the two
wiring configurations 610, 630 of FIG. 19 and 20, every
quadrilateral array of four adjacent electromagnets 612, 632
defines a site for rotating a magnetic stirring bar, and the
diagonal members of each of the four adjacent electromagnets 612,
632 belong to the first series 614, 634 and the second 616, 636
series of electromagnets 612, 632. Moreover, within any set of four
adjacent electromagnets 612, 632, each pair of electromagnets 612,
632 belonging to the same series have opposite polarities. The two
wiring configurations 610, 630 of FIG. 19 and 20 can be used with
any of the arrays 460, 470, 480 shown in FIG. 12-14.
[0144] The complex wiring configurations 610, 630 of FIG. 19 and 20
can be placed on a printed circuit board, which serves as both a
mechanical support and alignment fixture for the electromagnets
612, 632. The use of a printed circuit board allows for rapid
interconnection of the electromagnets 612, 632, greatly reducing
assembly time and cost, and eliminating wiring errors associated
with manual soldering of hundreds of individual connections.
Switches can be used to turn stirring on and off for individual
rows of vessels. A separate drive circuit may be used for each row
of vessels, which allows stirring speed to be used as a variable
during an experiment.
[0145] FIG. 21 is a plot 650 of current versus time and shows the
phase relationship between sinusoidal source currents, I.sub.A(t)
652 and I.sub.B(t) 654, which drive, respectively, the first series
614, 634 and the second series 616, 636 of electromagnets 612, 632
shown in FIG. 19 and 20. The two source currents 652, 654 have
equivalent peak amplitude and frequency, .omega..sub.D, though
I.sub.A(t) 652 lags I.sub.B/(t) 654 by .pi./2 radians. Because of
this phase relationship, magnetic stirring bars placed at rotation
sites defined by any four adjacent electromagnets 612, 632 of FIG.
19 and 20 will each rotate at an angular frequency of
.omega..sub.D, though adjacent stirring bars will rotate in
opposite directions when the electromagnet array 460 depicted in
FIG. 12 is used. If, however, the arrays 470, 480 shown in FIG. 13
and 14 are used, adjacent stirring bars will rotate in the same
direction. In an alternate embodiment, a digital approximation to a
sine wave can be used.
[0146] FIG. 22 is a block diagram of a power supply 670 for an
electromagnet array 672. Individual electromagnets 674 are wired
together in a first and second series as, for example, shown in
FIG. 19 or 20. The first and second series of electromagnets 674
are connected to a power source 676, which provides the two series
with sinusoidal driving currents that are .pi./2 radians out of
phase. Normally, the amplitudes of the two driving currents are the
same and do not depend on frequency. A processor 678 controls both
the amplitude and the frequency of the driving currents.
Viscosity and Related Measurements
[0147] The present invention provides for in situ measurement of
viscosity and related properties. As discussed below, such data can
be used, for example, to monitor reactant conversion, and to rank
or characterize materials based on molecular weight or particle
size.
[0148] The viscosity of a polymer solution depends on the molecular
weight of the polymer and its concentration in solution. For
polymer concentrations well below the "semidilute limit"--the
concentration at which the solvated polymers begin to overlap one
another--the solution viscosity, .eta., is related to the polymer
concentration, C, in the limit as C approaches zero by the
expression 6. .eta.=(1+C[.eta.]).eta..sub.S VI
[0149] where .eta..sub.s is the viscosity of the solvent.
Essentially, adding polymer to a solvent increases the solvent's
viscosity by an amount proportional to the polymer concentration.
The proportionality constant [.eta.], is known as the intrinsic
viscosity, and is related to the polymer molecular weight, M,
through the expression 7. [.eta.]=[.eta..sub.0]M.sup..alpha.,
VII
[0150] where [.eta..sub.0] and .alpha. are empirical constants.
Equation VII is known as the Mark-Houwink-Sakurda (MHS) relation,
and it, along with equation VI, can be used to determine molecular
weight from viscosity measurements.
[0151] Equation VI requires concentration data from another source;
with polymerization reactions, polymer concentration is directly
related to monomer conversion. In the present invention, such data
can be obtained by measuring heat evolved during reaction (see
equation III and IV) or, as described below, by measuring the
amount of a gaseous reactant consumed during reaction. The
constants in the MHS relation are functions of temperature, polymer
composition, polymer conformation, and the quality of the
polymer-solvent interaction. The empirical constants, [.eta..sub.0]
and .alpha., have been measured for a variety of polymer-solvent
pairs, and are tabulated in the literature.
[0152] Although equations VI and VII can be used to approximate
molecular weight, in situ measurements of viscosity in the present
invention are used mainly to rank reaction products as a function
of molecular weight. Under most circumstances, the amount of
solvent necessary to satisfy the concentration requirement of
equation VI would slow the rate of reaction to an unacceptable
level. Therefore, most polymerizations are carried out at polymer
concentrations above the semidilute limit, where the use of
equations VI and VII to calculate molecular weight would lead to
large error. Nevertheless, viscosity can be used to rank reaction
products even at concentrations above the semidilute limit since a
rise in viscosity during reaction generally reflects an increase in
polymer concentration, molecular weight or both. If necessary, one
can accurately determine molecular weight from viscosity
measurements at relatively high polymer concentration by first
preparing temperature-dependent calibration curves that relate
viscosity to molecular weight. But the curves would have to be
obtained for every polymer-solvent pair produced, which weighs
against their use for screening new polymeric materials.
[0153] In addition to ranking reactions, viscosity measurements can
also be used to screen or characterize dilute suspensions of
insoluble particles--polymer emulsions or porous supports for
heterogeneous catalysts--in which viscosity increases with particle
size at a fixed number concentration. In the case of polymer
emulsions, viscosity can serve as a measure of emulsion quality.
For example, solution viscosity that is constant over long periods
of time may indicate superior emulsion stability, or viscosity
within a particular range may correlate with a desired emulsion
particle size. With porous supports, viscosity measurements can be
used to identify active catalysts: in many cases, the catalyst
support will swell during reaction due to the formation of
insoluble products within the porous support.
[0154] In accordance with the present invention, viscosity or
related properties of the reactant mixtures are monitored by
measuring the effect of viscous forces on stirring blade rotation.
Viscosity is a measure of a fluid's resistance to a shear force.
This shear force is equal to the applied torque, .GAMMA., needed to
maintain a constant angular velocity of the stirring blade. The
relationship between the viscosity of the reaction mixture and the
applied torque can be expressed as 8.
.GAMMA.=K.sub..omega.(.omega.,T).sub..eta., VIII
[0155] where K.sub..omega. is a proportionality constant that
depends on the angular frequency, .omega., of the stirring bar, the
temperature of the reaction mixture, and the geometries of the
reaction vessel and the stirring blade. K.sub..omega. can be
obtained through calibration with solutions of known viscosity.
[0156] During a polymerization, the viscosity of the reaction
mixture increases over time due to the increase in molecular weight
of the reaction product or polymer concentration or both. This
change in viscosity can be monitored by measuring the applied
torque and using equation VIII to convert the measured data to
viscosity. In many instances, actual values for the viscosity are
unnecessary, and one can dispense with the conversion step. For
example, in situ measurements of applied torque can be used to rank
reaction products based on molecular weight or conversion, as long
as stirring rate, temperature, vessel geometry and stirring blade
geometry are about the same for each reaction mixture.
[0157] FIG. 23 illustrates an apparatus 700 for directly measuring
the applied torque. The apparatus 700 comprises a stirring blade
702 coupled to a drive motor 704 via a rigid drive spindle 706. The
stirring blade 702 is immersed in a reaction mixture 708 contained
within a reactor vessel 710. Upper 712 and lower 714 supports
prevent the drive motor 704 and vessel 710 from rotating during
operation of the stirring blade 702. For simplicity, the lower
support 714 can be a permanent magnet. A torque or strain gauge 716
shown mounted between the upper support 712 and the drive motor 704
measures the average torque exerted by the motor 704 on the
stirring blade 702. In alternate embodiments, the strain gauge 716
is inserted within the drive spindle 706 or is placed between the
vessel 710 and the lower support 714. If located within the drive
spindle 706, a system of brushes or commutators (not shown) are
provided to allow communication with the rotating strain gauge.
Often, placement of the strain gauge 716 between the vessel 710 and
the lower support 714 is the best option since many stirring
systems, such as the one shown in FIG. 10, use a single motor to
drive multiple stirring blades.
[0158] FIG. 24 shows placement of a strain gauge 730 in a portion
of a base plate 732 that is similar to the lower plate 400 of the
reactor module 390 shown in FIG. 10. The lower end 734 of the
strain gauge 730 is rigidly attached to the base plate 732. A first
permanent magnet 736 is mounted on the top end 738 of the strain
gauge 730, and a second permanent magnet 740 is attached to the
bottom 742 of a reactor vessel 744. When the vessel 744 is inserted
in the base plate 732, the magnetic coupling between the first
magnet 736 and the second magnet 740 prevents the vessel 744 from
rotating and transmits torque to the strain gauge 730.
[0159] Besides using a strain gauge, one can also monitor drive
motor power consumption, which is related to the applied torque.
Referring again to FIG. 23, the method requires monitoring and
control of the stirring blade 702 rotational speed, which can be
accomplished by mounting a sensor 718 adjacent to the drive spindle
706. Suitable sensors 718 include optical detectors, which register
the passage of a spot on the drive spindle 706 by a reflectance
measurement, or which note the interruption of a light beam by an
obstruction mounted on the drive spindle 706, or which discern the
passage of a light beam through a slot on the drive spindle 706 or
on a co-rotating obstruction. Other suitable sensors 718 include
magnetic field detectors that sense the rotation of a permanent
magnet affixed to the spindle 706. Operational details of magnetic
field sensors are described below in the discussion of phase lag
detection. Sensors such as encoders, resolvers, Hall effect
sensors, and the like, are commonly integrated into the motor 704.
An external processor 720 adjusts the power supplied to the drive
motor 704 to maintain a constant spindle 706 rotational speed. By
calibrating the required power against a series of liquids of known
viscosity, the viscosity of an unknown reaction mixture can be
determined.
[0160] In addition to direct measurement, torque can be determined
indirectly by measuring the phase angle or phase lag between the
stirring blade and the driving force or torque. Indirect
measurement requires that the coupling between the driving torque
and the stirring blade is "soft," so that significant and
measurable phase lag occurs.
[0161] With magnetic stirring, "soft" coupling occurs
automatically. The torque on the stirring bar is related to the
magnetic moment of the stirring bar, .mu., and the amplitude of the
magnetic field that drives the rotation of the stirring bar, H,
through the expression 9. .GAMMA.=.mu.H sin .theta., IX
[0162] where .theta. is the angle between the axis of the stirring
bar (magnetic moment) and the direction of the magnetic field. At a
given angular frequency, and for known .mu. and H, the phase angle,
.theta., will automatically adjust itself to the value necessary to
provide the amount of torque needed at that frequency. If the
torque required to stir at frequency .omega. is proportional to the
solution viscosity and the stirring frequency--an approximation
useful for discussion--then the viscosity can be calculated from
measurements of the phase angle using the equation 10.
.GAMMA.=.mu.H sin.theta.=.alpha..eta..omega. X
[0163] where a is a proportionality constant that depends on
temperature, and the geometry of the vessel and the stirring blade.
In practice, one may use equation VIII or a similar empirical
expression for the right hand side of equation X if the torque does
not depend linearly on the viscosity-frequency product.
[0164] FIG. 25 shows an inductive sensing coil system 760 for
measuring phase angle or phase lag, .theta.. The system 760
comprises four electromagnets 762, which drive the magnetic
stirring bar 764, and a phase-sensitive detector, such as a
standard lock-in amplifier (not shown). A gradient coil 766
configuration is used to sense motion of the stirring bar 764,
though many other well known inductive sensing coil configurations
can be used. The gradient coil 766 is comprised of a first sensing
coil 768 and a second sensing coil 770 that are connected in series
and are wrapped in opposite directions around a first electromagnet
772. Because of their opposite polarities, any difference in
voltages induced in the two sensing coils 768, 770 will appear as a
voltage difference across the terminals 774, which is detected by
the lock-in amplifier. If no stirring bar 764 is present, then the
alternating magnetic field of the first electromagnet 772 will
induce approximately equal voltages in each of the two coils 768,
770--assuming they are mounted symmetrically with respect to the
first electromagnet 772--and the net voltage across the terminals
774 will be about zero. When a magnetic stirring bar 764 is
present, the motion of the rotating magnet 764 will induce a
voltage in each of the two sensing coils 768, 770. But, the voltage
induced in the first coil 768, which is closer to the stirring bar
764, will be much larger than the voltage induced in the second
coil 770, so that the voltage across the terminals 774 will be
nonzero. A periodic signal will thus be induced in the sensing
coils 768, 770, which is measured by the lock-in amplifier.
[0165] FIG. 26 and FIG. 27 show typical outputs 790, 810 from the
inductive sensing coil system 760 of FIG. 25, which illustrate
phase lag associated with magnetic stirring for low and high
viscosity solutions, respectively. Periodic signals 792, 812 from
the sensing coils 768, 770 are plotted with sinusoidal reference
signals 794, 814 used to drive the electromagnets. Time delay,
.DELTA.t 796, 816, between the periodic signals 792, 812 and the
reference signals 794, 814 is related to the phase angle by
.theta.=.omega..DELTA.t. Visually comparing the two outputs 790,
810 indicates that the phase angle associated with the high
viscosity solution is larger than the phase angle associated with
the low viscosity solution.
[0166] FIG. 27 illustrates how amplitude and phase angle will vary
during a reaction as the viscosity increases from a low value to a
value sufficient to stall the stirring bar. A waveform or signal
820 from the sensing coils is input to a lock-in amplifier 822,
using the drive circuit sinusoidal current as a phase and frequency
reference signal 824. The lock-in amplifier 822 outputs the
amplitude 826 of the sensing coil signal 820, and phase angle 828
or phase lag relative to the reference signal 824. The maximum
phase angle is .pi./2 radians, since, as shown by equation X,
torque decreases with further increases in .theta. leading to slip
of the stirring bar 764 of FIG. 25. Thus, as viscosity increases
during reaction, the phase angle 828 or phase lag also increases
until the stirring bar stalls, and the amplitude 826 abruptly drops
to zero. This can be seen graphically in FIG. 27, which shows plots
of {overscore (A)} 830 and {overscore (.theta.)} 832, the amplitude
of the reference signal and phase angle, respectively, averaged
over many stirring bar rotations. One can optimize the sensitivity
of the phase angle 828 measurement by proper choice of the magnetic
field amplitude and frequency.
[0167] To minimize interference from neighboring stirring
bars--ideally, each set of gradient coils should sense the motion
of a single stirring bar--each vessel should be provided with
electromagnets that are not shared with adjacent vessels. For
example, a 4:1 magnet array shown in FIG. 14 should be used instead
of the 2:1 or the 1:1 magnet arrays shown in FIG. 13 and 12,
respectively. In order to take readings from all of the vessels in
an array, a multiplexer can be used to sequentially route signals
from each vessel to the lock-in amplifier. Normally, an accurate
measurement of the phase angle can be obtained after several tens
of rotations of the stirring bars. For rotation frequencies of
10-20 Hz, this time will be on the order of a few seconds per
vessel. Thus, phase angle measurements for an entire array of
vessels can be typically made once every few minutes, depending on
the number of vessels, the stirring bar frequency, and the desired
accuracy. In order to speed up the measurement process, one may
employ multiple-channel signal detection to measure the phase angle
of stirring bars in more than one vessel at a time. Alternate
detection methods include direct digitization of the coil output
waveforms using a high-speed multiplexer and/or an
analog-to-digital converter, followed by analysis of stored
waveforms to determine amplitude and phase angle.
[0168] Phase angle measurements can also be made with non-magnetic,
mechanical stirring drives, using the inductive coil system 760 of
FIG. 25. For example, one may achieve sufficient phase lag between
the stirring blade and the drive motor by joining them with a
torsionally soft, flexible connector. Alternatively, the drive
mechanism may use a resilient belt drive rather than a rigid gear
drive to produce measurable phase lag. The stirring blade must
include a permanent magnet oriented such that its magnetic moment
is not parallel to the axis of rotation. For maximum sensitivity,
the magnetic moment of the stirring blade should lie in the plane
of rotation. Note that one advantage to using a non-magnetic
stirring drive is that there is no upper limit on the phase
angle.
[0169] In addition to directly or indirectly measuring torque, one
may sense viscosity by increasing the driving frequency,
.omega..sub.D, or decreasing the magnetic field strength until, in
either case, the stirring bar stalls because of insufficient
torque. The point at which the stirring bar stops rotating can be
detected using the same setup depicted in FIG. 25 for measuring
phase angle. During a ramp up (down) of the driving frequency
(field strength), the magnitude of the lock-in amplifier output
will abruptly fall by a large amount when the stirring bar stalls.
The frequency or field strength at which the stirring bar stalls
can be correlated with viscosity: the lower the frequency or the
higher the field strength at which stalling occurs, the greater the
viscosity of the reaction mixture.
[0170] With appropriate calibration, the method can yield absolute
viscosity data, but generally the method is used to rank reactions.
For example, when screening multiple reaction mixtures, one may
subject all of the vessels to a series of step changes in either
frequency or field strength, while noting which stirring bars stall
after each of the step changes. The order in which the stirring
bars stall indicates the relative viscosity of the reaction
mixtures since stirring bars immersed in mixtures having higher
viscosity will stall early. Note that, in addition to providing
data on torque and stall frequency, the inductive sensing coil
system 760 of FIG. 25 and similar devices can be used as diagnostic
tools to indicate whether a magnetic stirring bar has stopped
rotating during a reaction.
Mechanical Oscillators
[0171] Piezoelectric quartz resonators or mechanical oscillators
can be used to evaluate the viscosity of reaction mixtures, as well
as a host of other material properties, including molecular weight,
specific gravity, elasticity, dielectric constant, and
conductivity. In a typical application, the mechanical oscillator,
which can be as small as a few mm in length, is immersed in the
reaction mixture. The response of the oscillator to an excitation
signal is obtained for a range of input signal frequencies, and
depends on the composition and properties of the reaction mixture.
By calibrating the resonator with a set of well characterized
liquid standards, the properties of the reaction mixture can be
determined from the response of the mechanical oscillator. Further
details on the use of piezoelectric quartz oscillators to measure
material properties are described in co-pending U.S. patent
application Ser. No. 09/133,171 "Method and Apparatus for
Characterizing Materials by Using a Mechanical Resonator," filed
Aug. 12, 1998, issued May 28, 2002, as U.S. Pat. No. 6,393,895,
which is herein incorporated by reference.
[0172] Although many different kinds of mechanical oscillators
currently exist, some are less useful for measuring properties of
liquid solutions. For example, ultrasonic transducers or
oscillators cannot be used in all liquids due to diffraction
effects and steady acoustic (compressive) waves generated within
the reactor vessel. These effects usually occur when the size of
the oscillator and the vessel are not much greater than the
characteristic wavelength of the acoustic waves. Thus, for reactor
vessel diameters on the order of a few centimeters, the frequency
of the mechanical oscillator should be above 1 MHz. Unfortunately,
complex liquids and mixtures, including polymer solutions, often
behave like elastic gels at these high frequencies, which results
in inaccurate resonator response.
[0173] Often, shear-mode transducers as well as various
surface-wave transducers can be used to avoid some of the problems
associated with typical ultrasonic transducers. Because of the
manner in which they vibrate, shear mode transducers generate
viscous shear waves instead of acoustic waves. Since viscous shear
waves decay exponentially with distance from the sensor surface,
such sensors tend to be insensitive to the geometry of the
measurement volume, thus eliminating most diffraction and
reflection problems. Unfortunately, the operating frequency of
these sensors is also high, which, as mentioned above, restricts
their use to simple fluids. Moreover, at high vibration
frequencies, most of the interaction between the sensor and the
fluid is confined to a thin layer of liquid near the sensor
surface. Any modification of the sensor surface through adsorption
of solution components will often result in dramatic changes in the
resonator response.
[0174] Tuning forks 840 and bimorph/unimorph resonators 850 shown
in FIG. 28 and FIG. 29, respectively, overcome many of the
drawbacks associated with ultrasonic transducers. Because of their
small size, tuning forks 840 and bimorph/unimorph resonators 850
have difficulty exciting acoustic waves, which typically have
wavelengths many times their size. Furthermore, though one might
conclude otherwise based on the vibration mode shown in FIG. 28,
tuning forks 840 generate virtually no acoustic waves: when
excited, each of the tines 832 of the tuning fork 840 acts as a
separate acoustic wave generator, but because the tines 832
oscillate in opposite directions and phases, the waves generated by
each of the tines 832 cancel one another. Like the shear mode
transducers described above, the bimorph/unimorph 850 resonators
produce predominantly viscous waves and therefore tend to be
insensitive to the geometry of the measurement volume. But unlike
the shear mode transducers, bimorph/unimorph 850 resonators operate
at much lower frequencies, and therefore can be used to measure
properties of polymeric solutions.
[0175] FIG. 30 schematically shows a system 870 for measuring the
properties of reaction mixtures using mechanical oscillators 872.
An important advantage of the system 870 is that it can be used to
monitor the progress of a reaction. The oscillators 872 are mounted
on the interior walls 874 of the reaction vessels 876.
Alternatively, the oscillators 872 can be mounted along the bottom
878 of the vessels 876 or can be freestanding within the reaction
mixtures 880. Each oscillator 872 communicates with a network
analyzer 882 (for example, an HP8751A analyzer), which generates a
variable frequency excitation signal. Each of the oscillators 872
also serve as receivers, transmitting their response signals back
to the network analyzer 882 for processing. The network analyzer
882 records the responses of the oscillators 872 as functions of
frequency, and sends the data to storage 884. The output signals of
the oscillators 872 pass through a high impedance buffer amplifier
886 prior to measurement by the wide band receiver 888 of the
network analyzer 882.
[0176] Other resonator designs may be used. For example, to improve
the suppression of acoustic waves, a tuning fork resonator with
four tines can be used. It is also possible to excite resonator
oscillations through the use of voltage spikes instead of a
frequency sweeping AC source. With voltage spike excitation,
decaying free oscillations of the resonator are recorded instead of
the frequency response. A variety of signal processing techniques
well known to those of skill in the art can be used to distinguish
resonator responses.
[0177] Alternate embodiments can be described with reference to the
parallel reactor system 130 shown in FIG. 2. A single resonator
(not shown) is attached to the 3-axis translation system 150. The
translation system 150, at the direction of the processor 160,
places the resonator within a reactor vessel of interest. A reading
of resonator response is taken and compared to calibration curves,
which relate the response to viscosity, molecular weight, specific
gravity, or other properties. In another embodiment, a portion of
the reaction mixture is withdrawn from a reactor vessel, using, for
example, the liquid handling system 146, and is placed in a
separate vessel containing a resonator. The response of the
resonator is measured and compared to calibration data. Although
the system 870 shown in FIG. 30 is better suited to monitor
solution properties in situ, the two alternate embodiments can be
used as post-characterization tools and are much simpler to
implement.
[0178] In addition to mechanical oscillators, other types of
sensors can be used to evaluate material properties. For example,
interdigitated electrodes can be used to measure dielectric
properties of the reaction mixtures.
Pressure Control System
[0179] Another technique for assessing reaction kinetics is to
monitor pressure changes due to production or consumption of
various gases during reaction. One embodiment of this technique is
shown in FIG. 31. A parallel reactor 910 comprises a group of
reactor vessels 912. A gas-tight cap 914 seals each of the vessels
912 and prevents unintentional gas flow to or from the vessels 912.
Prior to placement of the cap 914, each of the vessels 912 is
loaded with liquid reactants, solvents, catalysts, and other
condensed-phase reaction components using the liquid handling
system 146 shown in FIG. 2. Gaseous reactants from source 916 are
introduced into each of the vessels 912 through a gas inlet 918.
Valves 920, which communicate with a controller 922, are used to
fill the reaction vessels 912 with the requisite amount of gaseous
reactants prior to reaction. A pressure sensor 924 communicates
with the vessel head space--the volume within each of the vessels
912 that separates the cap 914 from the liquid components--through
a port 926 located in the cap 914. The pressure sensors 924 are
coupled to a processor 928, which manipulates and stores data.
During reaction, any changes in the head space pressure, at
constant temperature, reflect changes in the amount of gas present
in the head space. This pressure data can be used to determine the
molar production or consumption rate, r.sub.i, of a gaseous
component since, for an ideal gas at constant temperature, 11.
.times. .times. r i = 1 R .times. .times. T .times. d p i d t XI
##EQU7##
[0180] where R is the universal gas constant and p.sub.i is the
partial pressure of the ith gaseous component. Temperature sensors
930, which communicate with the processor 928 through monitor 932,
provide data that can be used to account for changes in pressure
resulting from variations in head space temperature. The ideal gas
law or similar equation of state can be used to calculate the
pressure correction.
[0181] In an alternate embodiment, the valves 920 are used to
compensate for the consumption of a gaseous reactant, in a reaction
where there is a net loss in moles of gas-phase components. The
valves 920 are regulated by the valve controller 922, which
communicates with the processor 928. At the beginning of the
reaction, the valves 920 open to allow gas from the high pressure
source 916 to enter each of the vessels 912. Once the pressure
within each of the vessels 912, as read by the sensor 924, reaches
a predetermined value, P.sub.H, the processor 928 closes the valves
920. As the reaction consumes the source 916 gas, the total
pressure within each of the vessels 912 decreases. Once the
pressure in a particular vessel 912 falls below a predetermined
value, P.sub.L, the processor 928 opens the valve 920 associated
with the particular vessel 912, repressurizing it to P.sub.H. This
process--filling each of the vessels 912 with source 916 gas to
P.sub.H, allowing the head space pressure to drop below P.sub.L,
and then refilling the vessels 912 with source 916 gas to
P.sub.H--is usually repeated many times during the course of the
reaction. Furthermore, the total pressure in the head space of each
of the vessels 912 is continuously monitored and recorded during
the gas fill-pressure decay cycle.
[0182] An analogous method can be used to investigate reactions
where there is a net gain of gas-phase components. At the beginning
of a reaction, all reaction materials are introduced into the
vessels 912 and the valves 920 are closed. As the reaction
proceeds, gas production results in a rise in head space pressure,
which sensors 924 and processor 928 monitor and record. Once the
pressure within a particular vessel 912 reaches P.sub.H, the
processor 928 directs the controller 922 to open the appropriate
valve 920 to depressurize the vessel 912. The valve 920, which is a
multi-port valve, vents the gas from the head space through an
exhaust line 934. Once the head space pressure falls below P.sub.L,
the processor 928 instructs the controller 922 to close the valve
920. The total pressure is continuously monitored and recorded
during the gas rise-vent cycle.
[0183] The gas consumption (production) rates can be estimated from
the total pressure data by a variety of methods. For simplicity,
these methods are described in terms of a single reactor vessel 912
and valve 920, but they apply equally well to a parallel reactor
910 comprising multiple vessels 912 and valves 920. One estimate of
gas consumption (production) can be made from the slope of the
pressure decay (growth) curves obtained when the valve is closed.
These data, after converting total pressure to partial pressure
based on reaction stoichiometry, can be inserted into equation XI
to calculate r.sub.i, the molar consumption (production) rate. A
second estimate can be made by assuming that a fixed quantity of
gas enters (exits) the vessel during each valve cycle. The
frequency at which the reactor is repressurized (depressurized) is
therefore proportional to the gas consumption (production) rate. A
third, more accurate estimate can be obtained by assuming a known
gas flow rate through the valve. Multiplying this value by the time
during which the valve remains open yields an estimate for the
quantity of gas that enters or leaves the vessel during a
particular cycle. Dividing this product by the time between the
next valve cycle--that is, the time it takes for the pressure in
the vessel head space to fall from P.sub.H to P.sub.L--yields an
average value for the volumetric gas consumption (production) rate
for the particular valve cycle. Summing the quantity of gas added
during all of the cycles equals the total volume of gas consumed
(produced) during the reaction.
[0184] The most accurate results are obtained by directly measuring
the quantity of gas that flows through the valve. This can be done
by noting the change in pressure that occurs during the time the
valve is open--the ideal gas law can be used to convert this change
to the volume of gas that enters or leaves the vessel. Dividing
this quantity by the time between a particular valve cycle yields
an average volumetric gas consumption (production) rate for that
cycle. Summing the volume changes for each cycle yields the total
volume of gas consumed (produced) in the reaction.
[0185] In an alternate embodiment shown in FIG. 31, the gas
consumption rate is directly measured by inserting flow sensors 936
downstream of the valves 920 or by replacing the valves 920 with
flow sensors 936. The flow sensors 936 allow continuous monitoring
of the mass flow rate of gas entering each of the vessels 912
through the gas inlet 918. To ensure meaningful comparisons between
experiments, the pressure of the source 916 gas should remain about
constant during an experiment. Although the flow sensors 936
eliminate the need for cycling the valves 920, the minimum
detectable flow rates of this embodiment are less than those
employing pressure cycling. But, the use of flow sensors 936 is
generally preferred for fast reactions where the reactant flow
rates into the vessels 912 are greater than the threshold
sensitivity of the flow sensors 936.
[0186] Illustrative Example of Calibration of Mechanical
Oscillators for Measuring Molecular Weight
[0187] Mechanical oscillators were used to characterize reaction
mixtures comprising polystyrene and toluene. To relate resonator
response to the molecular weight of polystyrene, the system 870
illustrated in FIG. 30 was calibrated using polystyrene standards
of known molecular weight dissolved in toluene. Each of the
standard polystyrene-toluene solutions had the same concentration,
and were run in separate (identical) vessels using tuning fork
piezoelectric quartz resonators similar to the one shown in FIG.
28. Frequency response curves for each resonator were recorded at
intervals between about 10 and 30 seconds.
[0188] The calibration runs produced a set of resonator responses
that could be used to relate the output from the oscillators 872
immersed in reaction mixtures to polystyrene molecular weight. FIG.
32 shows results of calibration runs 970 for the
polystyrene-toluene solutions. The curves are plots of oscillator
response for polystyrene-toluene solutions comprising no
polystyrene 952, and polystyrene standards having weight average
molecular weights (M.sub.w) of 2.36.times.10.sup.3 954,
13.7.times.10.sup.3 956, 114.2.times.10.sup.3 958, and
1.88.times.10.sup.6 960.
[0189] FIG. 33 shows a calibration curve 970 obtained by
correlating M.sub.w of the polystyrene standards with the distance
between the frequency response curve for toluene 952 and each of
the polystyrene solutions 954, 956, 958, 960 of FIG. 32. This
distance was calculated using the expression: 12. .times. .times. d
i = 1 f 1 - f 0 .times. .intg. f 0 f 1 .times. ( R 0 - R i ) 2
.times. d f , XII ##EQU8##
[0190] where f.sub.0 and f.sub.1 are the lower and upper
frequencies of the response curve, respectively; R.sub.0 is the
frequency response of the resonator in toluene, and R.sub.i is the
resonator response in a particular polystyrene-toluene solution.
Given response curves for an unknown polystyrene-toluene mixture
and pure toluene 952 (FIG. 32), the distance between the two curves
can be determined from equation XII. The resulting d.sub.i can be
located along the calibration curve 970 of FIG. 33 to determine
M.sub.w for the unknown polystyrene-toluene solution.
Illustrative Example of Measurement of Gas-Phase Reactant
Consumption by Pressure Monitoring and Control
[0191] FIG. 34 depicts the pressure recorded during solution
polymerization of ethylene to polyethylene. The reaction was
carried out in an apparatus similar to that shown in FIG. 31. An
ethylene gas source was used to compensate for ethylene consumed in
the reaction. A valve, under control of a processor, admitted
ethylene gas into the reaction vessel when the vessel head space
pressure dropped below P.sub.L.apprxeq.16.1 psig due to consumption
of ethylene. During the gas filling portion of the cycle, the valve
remained open until the head space pressure exceeded
P.sub.H.apprxeq.20.3 psig.
[0192] FIG. 35 and FIG. 36 show ethylene consumption rate as a
function of time, and the mass of polyethylene formed as a function
of ethylene consumed, respectively. The average ethylene
consumption rate, -r.sub.C2,k (atmmin.sup.-1), was determined from
the expression 13. .times. - r C .times. .times. 2 , k = ( P H - P
L ) k .DELTA. .times. .times. t k XIII ##EQU9##
[0193] where subscript k refers to a particular valve cycle, and
.DELTA.t.sub.k is the time interval between the valve closing
during the present cycle and the valve opening at the beginning of
the next cycle. As shown in FIG. 35, the constant ethylene
consumption rate at later times results from catalyzed
polymerization of ethylene. The high ethylene consumption rate
early in the process results primarily from transport of ethylene
into the catalyst solution prior to establishing an equilibrium
ethylene concentration in the liquid phase. FIG. 36 shows the
amount of polyethylene produced as a function of the amount of
ethylene consumed by reaction. The amount of polyethylene produced
was determined by weighing the reaction products, and the amount of
ethylene consumed by reaction was estimated by multiplying the
constant average consumption rate by the total reaction time. A
linear least-squares fit to these data yields a slope which matches
the value predicted from the ideal gas law and from knowledge of
the reaction temperature and the total volume occupied by the gas
(the product of vessel head space and number of valve cycles during
the reaction).
Automated, High Pressure Injection System
[0194] FIG. 37 shows a perspective view of an eight-vessel reactor
module 1000, of the type shown in FIG. 10, which is fitted with an
optional liquid injection system 1002. The liquid injection system
1002 allows addition of liquids to pressurized vessels, which, as
described below, alleviates problems associated with pre-loading
vessels with catalysts. In addition, the liquid injection system
1002 improves concurrent analysis of catalysts by permitting
screening reactions to be selectively quenched through the addition
of a liquid-phase catalyst poison.
[0195] The liquid injection system 1002 helps solve problems
concerning liquid-phase catalytic polymerization of a gaseous
monomer. When using the reactor module 390 shown in FIG. 10 to
screen or characterize polymerization catalysts, each vessel is
normally loaded with a catalyst and a solvent prior to reaction.
After sealing, gaseous monomer is introduced into each vessel at a
specified pressure to initiate polymerization. As discussed in
Example 1, during the early stages of reaction, the monomer
concentration in the solvent increases as gaseous monomer dissolves
in the solvent. Although the monomer eventually reaches an
equilibrium concentration in the solvent, catalyst activity may be
affected by the changing monomer concentration prior to
equilibrium. Moreover, as the monomer dissolves in the solvent
early in the reaction, additional gaseous monomer is added to
maintain the pressure in the vessel headspace. This makes it
difficult to distinguish between pressure changes in the vessels
due to polymerization in the liquid phase and pressure changes due
to monomer transport into the solvent to establish an equilibrium
concentration. These analytical difficulties can be avoided using
the liquid injection system 1002, since the catalyst can be
introduced into the vessels after the monomer has attained an
equilibrium concentration in the liquid phase.
[0196] The liquid injection system 1002 of FIG. 37 also helps solve
problems that arise when using the reactor module 390 shown in FIG.
10 to investigate catalytic co-polymerization of gaseous and liquid
co-monomers. Prior to reaction, each vessel is loaded with a
catalyst and the liquid co-monomer. After sealing the vessels,
gaseous co-monomer is introduced into each vessel to initiate
co-polymerization. However, because appreciable time may elapse
between loading of liquid components and contact with the gaseous
co-monomer, the catalyst may homo-polymerize a significant fraction
of the liquid co-monomer. In addition, the relative concentration
of the co-monomers in the liquid-phase changes during the early
stages of reaction as the gaseous co-monomer dissolves in the
liquid phase. Both effects lead to analytical difficulties that can
be avoided using the liquid injection system 1002, since catalysts
can be introduced into the vessels after establishing an
equilibrium concentration of the gaseous and liquid co-monomers in
the vessels. In this way, the catalyst contacts the two co-monomers
simultaneously.
[0197] The liquid injector system 1002 shown in FIG. 37 also allows
users to quench reactions at different times by adding a liquid
phase catalyst poison, which improves screening of materials
exhibiting a broad range of catalytic activity. When using the
reactor module 390 of FIG. 10 to concurrently evaluate library
members for catalytic performance, the user may have little
information about the relative activity of library members. If
every reaction is allowed to proceed for the same amount of time,
the most active catalysts may generate an excessive amount of
product, which can hinder post reaction analysis and reactor clean
up. Conversely, the least active catalysts may generate an amount
of product insufficient for characterization. By monitoring the
amount of product in each of the vessels--through the use of
mechanical oscillators or phase lag measurements, for instance--the
user can stop a particular reaction by injecting the catalyst
poison into the vessels once a predetermined conversion is
achieved. Thus, within the same reactor and in the same experiment,
low and high activity catalysts may undergo reaction for relatively
long and short time periods, respectively, with both sets of
catalysts generating about the same amount of product.
[0198] Referring again to FIG. 37, the liquid injection system 1002
comprises fill ports 1004 attached to an injector manifold 1006. An
injector adapter plate 1008, sandwiched between an upper plate 1010
and block 1012 of the reactor module 1000, provides conduits for
liquid flow between the injector manifold 1006 and each of the
wells or vessels (not shown) within the block 1012. Chemically
inert valves 1014 attached to the injector manifold 1006 and
located along flow paths connecting the fill ports 104 and the
conduits within the adapter plate 1008, are used to establish or
prevent fluid communication between the fill ports 1004 and the
vessels or wells. Normally, the liquid injection system 1002 is
accessed through the fill ports 1004 using a probe 1016, which is
part of an automated liquid delivery system such as the robotic
material handling system 146 shown in FIG. 2. However, liquids can
be manually injected into the vessels through the fill ports 1004
using a pipette, syringe, or similar liquid delivery device.
Conventional high-pressure liquid chromatography loop injectors can
be used as fill ports 1004. Other useful fill ports 1004 are shown
in FIG. 38 and FIG. 39.
[0199] FIG. 38 shows a cross sectional view of a first embodiment
of a fill port 1004' having an o-ring seal to minimize liquid
leaks. The fill port 1004' comprises a generally cylindrical fill
port body 1040 having a first end 1042 and a second end 1044. An
axial bore 1046 runs the length of the fill port body 1040. An
elastomeric o-ring 1048 is seated within the axial bore 1046 at a
point where there is an abrupt narrowing 1050, and is held in place
with a sleeve 1052 that is threaded into the first end 1042 of the
fill port body 1040. The sleeve 1052 has a center hole 1054 that is
sized to accommodate the widest part of the probe 1016. The sleeve
1052 is typically made from a chemically resistant plastic, such as
polyethylethylketone (PEEK), polytetrafluoroethylene (PTFE), and
the like, which minimizes damage to the probe 1016 and fill port
1004' during liquid injection. To aid in installation and removal,
the fill port 1004' has a knurled first outer surface 1056 located
adjacent to the first end 1042 of the fill port 1004', and a
threaded second outer surface 1058, located adjacent to the second
end 1044 of the fill port 1004'.
[0200] FIG. 38 also shows the position of the probe 1016 during
liquid injection. Like a conventional pipette, the probe 1016 is a
cylindrical tube having an outer diameter (OD) at the point of
liquid delivery that is smaller than the OD over the majority of
the probe 1016 length. As a result, near the probe tip 1060, there
is a transition zone 1062 where the probe 1016 OD narrows. Because
the inner diameter (ID) of the o-ring 1048 is about the same as the
OD of the probe tip 1060, a liquid-tight seal is formed along the
probe transition zone 1060 during liquid injection.
[0201] FIG. 39 shows a second embodiment of a fill port 1004''.
Like the first embodiment 1004' shown in FIG. 38, the second
embodiment 1004'' comprises a generally cylindrical fill port body
1040' having a first end 1042' and a second end 1044'. But instead
of an o-ring, the fill port 1004'' shown in FIG. 39 employs an
insert 1080 having a tapered axial hole 1082 that results an
interference fit, and hence a seal, between the probe tip 1060 and
the ID of the tapered axial hole 1082 during liquid injection. The
insert 1080 can be threaded into the first end 1042' of the fill
port 1004''. Typically, the insert 1080 is made from a chemically
resistant plastic, such as PEEK, PTFE, and the like, which
minimizes damage to the probe 1016 and fill port 1004'' during
liquid injection. To aid in removal and installation, the fill
port' has a knurled first outer surface 1056' located adjacent to
the first end 1042' of the fill port 1004'', and a threaded second
outer surface 1058' located adjacent to the second end 1044' of the
fill port 1004''.
[0202] FIG. 40 shows a phantom front view of the injector manifold
1006. The injector manifold 1006 includes a series of fill port
seats 1100 located along a top surface 1102 of the injector
manifold 1006. The fill port seats 1100 are dimensioned to receive
the second ends 1044, 1044' of the fill ports 1004', 1004'' shown
in FIG. 38 and FIG. 39. Locating holes 1104, which extend through
the injector manifold 1006, locate the valves 1014 of FIG. 37 along
the front of the injector manifold 1006.
[0203] An alternative design for the valve 1014, which is used with
the injection ports is shown is FIG. 40A and FIG. 40B. FIG. 40A
shows the injector manifold 1006, which is shown in a cross
sectional view in FIG. 40B. The alternative valve design is
essentially a check valve that has a spring 2005 under a poppet
2006. When not injecting, the spring 2005 assisted by the pressure
of the reaction vessel pushes the poppet 2006 against a seal 2007
to seal the reaction vessel. The seal may be of a type known to
those of skill in the art, such as an o-ring seal. When injecting,
a pump associated with the probe 1016 forces the material to be
injected against the poppet 2006 overcoming the pressure in the
chamber and the spring 2005 force to allow the material being
injected to flow past the poppet into the reaction vessel via the
channel in the module.
[0204] FIG. 41 shows a cross sectional view of the injector
manifold 1006 along a first section line 1106 of FIG. 40. The cross
section illustrates one of a group of first flow paths 1130. The
first flow paths 1130 extend from the fill port seats 1100, through
the injector manifold 1006, to valve inlet seats 1132. Each of the
valve inlet seats 1132 is dimensioned to receive an inlet port (not
shown) of one of the valves 1014 depicted in FIG. 37. The first
flow paths 1130 thus provide fluid communication between the fill
ports 1004 and the valves 1014 of FIG. 37.
[0205] FIG. 42 shows a cross sectional view of the injector
manifold 1006 along a second section line 1108 of FIG. 40. The
cross section illustrates one of a group of second flow paths 1150.
The second flow paths 1150 extend from valve outlet seats 1152,
through the injector manifold 1006, to manifold outlets 1154
located along a back surface 1156 of the injector manifold 1006.
Each of the valve outlet seats 1152 is dimensioned to receive an
outlet port (not shown) of one of the valves 1014 depicted in FIG.
37. The manifold outlets 1154 mate with fluid conduits on the
injector adapter plate 1008. Annular grooves 1158, which surround
the manifold outlets 1154, are sized to receive o-rings (not shown)
that seal the fluid connection between the manifold outlets 1154
and the fluid conduits on the injector adapter plate 1008. The
second flow paths 1150 thus provide fluid communication between the
valves 1014 and the injector adapter plate 1008.
[0206] FIG. 43 shows a phantom top view of the injector adapter
plate 1008, which serves as an interface between the injector
manifold 1006 and the block 1012 of the reactor module 1000 shown
in FIG. 37. The injector adapter plate 1008 comprises holes 1180
that provide access to the vessels and wells within the block 1012.
The injector adapter plate 1008 also comprises conduits 1182
extending from a front edge 1184 to the bottom surface of the
adapter plate 1008. When the adapter plate 1008 is assembled in the
reactor module 1000, inlets 1186 of the conduits 1182 make fluid
connection with the manifold outlets 1154 shown in FIG. 42.
[0207] As shown in FIG. 44, which is a cross sectional side view of
the injector adapter plate 1008 along a section line 1188 of FIG.
43, the conduits 1182 terminate on a bottom surface 1210 of the
injector plate 1008 at conduit outlets 1212. The bottom surface
1210 of the adapter plate 1008 forms an upper surface of each of
the wells in the reactor module 1000 block 1012 of FIG. 37. To
ensure that liquid is properly delivered into the reaction vessels,
elongated well injectors, as shown in FIG. 45 and FIG. 48 below,
are connected to the conduit outlets 1212.
[0208] FIG. 45 shows an embodiment of a well injector 1230. The
well injector 1230 is a generally cylindrical tube having a first
end 1232 and a second end 1234. The well injector 1230 has a
threaded outer surface 1236 near the first end 1232 so that it can
be attached to threaded conduit outlets 1212 shown in FIG. 44.
Flats 1238 located adjacent to the threaded outer surface 1236
assist in twisting the first end 1232 of the well injector 1230
into the conduit outlets 1212. The length of the well injector 1230
can be varied. For example, the second end 1234 of the well
injector 1230 may extend into the liquid mixture; alternatively,
the second end 1234 of the injector 1230 may extend a portion of
the way into the vessel headspace. Typically, the well injector
1230 is made from a chemically resistant plastic, such PEEK, PTFE,
and the like.
[0209] Liquid injection can be understood by referring to FIG.
46-48. FIG. 46 shows a top view of the reactor module 1000, and
FIG. 47 and FIG. 48 show, respectively, cross sectional side views
of the reactor module 1000 along first and second section lines
1260, 1262 shown in FIG. 46. Prior to injection of a catalyst or
other liquid reagent, the probe 1016, which initially contains a
first solvent, withdraws a predetermined amount of the liquid
reagent from a reagent source. Next, the probe 1016 withdraws a
predetermined amount of a second solvent from a second solvent
source, resulting in a slug of liquid reagent suspended between the
first and second solvents within the probe 1016. Generally, probe
manipulations are carried out using a robotic material handling
system of the type shown in FIG. 2, and the second solvent is the
same as the first solvent.
[0210] FIG. 47 and 48 show the inlet and outlet paths of the valve
1014 prior to, and during, liquid injection, respectively. Once the
probe 1016 contains the requisite amount of liquid reagent and
solvents, the probe tip 1058 is inserted in the fill port 1004,
creating a seal as shown, for example, in FIG. 38 and FIG. 39. The
valve 1014 is then opened, and the second solvent, liquid reagent,
and a portion of the first solvent are injected into the reactor
module 1000 under pressure. From the fill port 1004, the liquid
flows into the injector manifold 1006 through one of the first flow
paths 1130 that extend from the fill port seats 1100 to the valve
inlet seats 1132. The liquid enters the valve 1014 through an inlet
port 1280, flows through a valve flow path 1282, and exits the
valve 1014 through an outlet port 1284. After leaving the valve
1014, the liquid flows through one of the second flow paths 1150 to
a manifold outlet 1154. From the manifold outlet 1154, the liquid
flows through the injector adapter plate 1008 within one of the
fluid conduits 1182, and is injected into a reactor vessel 1286 or
well 1288 through the well injector 1230. In the embodiment shown
in FIG. 48, the second end 1234 of the well injector 1230 extends
only a fraction of the way into the vessel headspace 1290. In other
cases, the second end 1234 may extend into the reaction mixture
1292.
[0211] Liquid injection continues until the slug of liquid reagent
is injected into the reactor vessel 1286 and the flow path from the
fill port 1004 to the second end 1234 of the well injector 1230 is
filled with the first solvent. At that point, the valve 1014 is
closed, and the probe 1016 is withdrawn from the fill port
1004.
Reactor Vessel Pressure Seal and Magnetic Feed-Through Stirring
Mechanism
[0212] FIG. 48 shows a stirring mechanism and associated seals for
maintaining above-ambient pressure in the reactor vessels 1286. The
direct-drive stirring mechanism 1310 is similar to the one shown in
FIG. 10, and comprises a gear 1312 attached to a spindle 1314 that
rotates a blade or paddle 1316. A dynamic lip seal 1318, which is
secured to the upper plate 1010 prevents gas leaks between the
rotating spindle 1314 and the upper plate 1010. When newly
installed, the lip seal is capable of maintaining pressures of
about 100 psig. However, with use, the lip seal 1318, like o-rings
and other dynamic seals, will leak due to frictional wear. High
service temperatures, pressures, and stirring speeds hasten dynamic
seal wear.
[0213] FIG. 49 shows a cross sectional view of a magnetic feed
through 1340 stirring mechanism that helps minimize gas leaks
associated with dynamic seals. The magnetic feed-through 1340
comprises a gear 1342 that is attached to a magnetic driver
assembly 1344 using cap screws 1346 or similar fasteners. The
magnetic driver assembly 1344 has a cylindrical inner wall 1348 and
is rotatably mounted on a rigid cylindrical pressure barrier 1350
using one or more bearings 1352. The bearings 1352 are located
within an annular gap 1354 between a narrow head portion 1356 of
the pressure barrier 1350 and the inner wall 1348 of the magnetic
driver assembly 1344. A base portion 1358 of the pressure barrier
1350 is affixed to the upper plate 1010 of the reactor module 1000
shown in FIG. 48 so that the axis of the pressure barrier 1350 is
about coincident with the centerline of the reactor vessel 1286 or
well 1288. The pressure barrier 1350 has a cylindrical interior
surface 1360 that is open only along the base portion 1358 of the
pressure barrier 1350. Thus, the interior surface 1360 of the
pressure barrier 1350 and the reactor vessel 1286 or well 1288
define a closed chamber.
[0214] As can be seen in FIG. 49, the magnetic feed through 1340
further comprises a cylindrical magnetic follower 1362 rotatably
mounted within the pressure barrier 1350 using first 1364 and
second 1366 flanged bearings. The first 1364 and second 1366
flanged bearings are located in first 1368 and second 1370 annular
regions 1368 delimited by the interior surface 1360 of the pressure
barrier 1350 and relatively narrow head 1372 and leg 1374 portions
of the magnetic follower 1362, respectively. A keeper 1376 and
retaining clip 1378 located within the second annular region 1370
adjacent to the second flanged bearing 1366 help minimize axial
motion of the magnetic follower 1362. A spindle (not shown)
attached to the free end 1380 of the leg 1374 of the magnetic
follower 1362, transmits torque to the paddle 1316 immersed in the
reaction mixture 1292 shown in FIG. 48.
[0215] During operation, the rotating gear 1342 and magnetic driver
assembly 1344 transmit torque through the rigid pressure barrier
1350 to the cylindrical magnetic follower 1362. Permanent magnets
(not shown) embedded in the magnetic driver assembly 1344 have
force vectors lying in planes about perpendicular to the axis of
rotation 1382 of the magnetic driver assembly 1344 and follower
1362. These magnets are coupled to permanent magnets (not shown)
that are similarly aligned and embedded in the magnetic follower
1362. Because of the magnetic coupling, rotation of the driver
assembly 1344 induces rotation of the follower 1362 and stirring
blade or paddle 1316 of FIG. 48. The follower 1362 and paddle 1316
rotate at the same frequency as the magnetic driver assembly,
though, perhaps, with a measurable phase lag.
Removable and Disposable Stirrer
[0216] The stirring mechanism 1310 shown in FIG. 48 includes a
multi-piece spindle 1314 comprising an upper spindle portion 1400,
a coupler 1402, and a removable stirrer 1404. The multi-piece
spindle 1314 offers certain advantages over a one-piece spindle.
Typically, only the upper drive shaft 1400 and the coupler 1402 are
made of a high modulus material such as stainless steel: the
removable stirrer 1404 is made of a chemically resistant and
inexpensive plastic, such as PEEK, PTFE, and the like. In contrast,
one-piece spindles, though perhaps coated with PTFE, are generally
made entirely of a relatively expensive high modulus material, and
are therefore normally reused. However, one-piece spindles are
often difficult to clean after use, especially following a
polymerization reaction. Furthermore, reaction product may be lost
during cleaning, which leads to errors in calculating reaction
yield. With the multi-piece spindle 1314, one discards the
removable stirrer 1404 after a single use, eliminating the cleaning
step. Because the removable stirrer 1404 is less bulky than the
one-piece spindle, it can be included in certain post-reaction
characterizations, including product weighing to determine reaction
yield.
[0217] FIG. 50 shows a perspective view of the stirring mechanism
1310 of FIG. 48, and provides details of the multi-piece spindle
1314. A gear 1312 is attached to the upper spindle portion 1400 of
the multi-piece spindle 1314. The upper spindle 1400 passes through
a pressure seal assembly 1420 containing a dynamic lip seal, and is
attached to the removable stirrer 1404 using the coupler 1402. Note
that the removable stirrer 1404 can also be used with the magnetic
feed through stirring mechanism 1340 illustrated in FIG. 49. In
such cases, the upper spindle 1400 is eliminated and the leg 1374
of the cylindrical magnetic follower 1362 or the coupler 1402 or
both are modified to attach the magnetic follower 1362 to the
removable stirrer 1404.
[0218] FIG. 51 shows details of the coupler 1402, which comprises a
cylindrical body having first 1440 and second 1442 holes centered
along an axis of rotation 1444 of the coupler 1402. The first hole
1440 is dimensioned to receive a cylindrical end 1446 of the upper
spindle 1400. A shoulder 1448 formed along the periphery of the
upper spindle 1400 rests against an annular seat 1450 located
within the first hole 1440. A set screw (not shown) threaded into a
locating hole 1452 prevents relative axial and rotational motion of
the upper spindle 1400 and the coupler 1402.
[0219] Referring to FIG. 50 and 51, the second hole 1442 of the
coupler 1402 is dimensioned to receive a first end 1454 of the
removable stirrer 1404. A pin 1456, which is embedded in the first
end 1454 of the removable stirrer, cooperates with a locking
mechanism 1458 located on the coupler 1402, to prevent relative
rotation of the coupler 1402 and the removable stirrer 1404. The
locking mechanism 1458 comprises an axial groove 1460 formed in an
inner surface 1462 of the coupler. The groove 1460 extends from an
entrance 1464 of the second hole 1442 to a lateral portion 1466 of
a slot 1468 cut through a wall 1470 of the coupler 1402.
[0220] As shown in FIG. 52, which is a cross sectional view of the
coupler 1402 along a section line 1472, the lateral portion 1466 of
the slot 1468 extends about 60 degrees around the circumference of
the coupler 1402 to an axial portion 1474 of the slot 1468. To
connect the removable stirrer 1404 to the coupler 1402, the first
end 1454 of the removable stirrer 1404 is inserted into the second
hole 1442 and then rotated so that the pin 1456 travels in the
axial groove 1460 and lateral portion 1466 of the slot 1468. A
spring 1476, mounted between the coupler 1402 and a shoulder 1478
formed on the periphery of the removable stirrer 1404, forces the
pin 1456 into the axial portion 1474 of the slot 1468.
[0221] An alternative design for the multi-piece spindle 1314 is
shown in FIG. 50A, which has an upper spindle portion 1400, a
coupler 1402 and a removable stirrer 1404. The details of this
alternative design are shown in FIG. 50B. This alternative design
is essentially a spring lock mechanism that allows for quick
removal of the removable stirrer 1404. The removable stirrer 1404
is locked in to the coupling mechanism by a series of balls 2001
that are held into a groove in the removable stirrer 1404 by a
collar 2002, which is part of the coupler 1402. The removable
stirrer 1404 is released by pulling the collar 2002 back against a
spring 2003 and allowing the balls 2001 to fall into a pocket in
the collar 2002 and releasing the removable stirrer.
Parallel Pressure Reactor Control and Analysis
[0222] FIG. 53 shows one implementation of a computer-based system
for monitoring the progress and properties of multiple reactions in
situ. Reactor control system 1500 sends control data 1502 to and
receives experimental data 1504 from reactor 1506. As will be
described in more detail below, in one embodiment reactor 1506 is a
parallel polymerization reactor and the control and experimental
data 1502 and 1504 include set point values for temperature,
pressure, time and stirring speed as well as measured experimental
values for temperature and pressure. Alternatively, in other
embodiments reactor 1506 can be any other type of parallel reactor
or conventional reactor, and data 1502, 1504 can include other
control or experimental data. System control module 1508 provides
reactor 1506 with control data 1502 based on system parameters
obtained from the user through user I/O devices 1510, such as a
display monitor, keyboard or mouse. Alternatively, system control
module 1508 can retrieve control data 1502 from storage 1512.
[0223] Reactor control system 1500 acquires experimental data 1504
from reactor 1506 and processes the experimental data in system
control module 1508 and data analysis module 1514 under user
control through user interface module 1516. Reactor control system
1500 displays the processed data both numerically and graphically
through user interface module 1516 and user I/O devices 1510, and
optionally through printer 1518.
[0224] FIG. 54 illustrates an embodiment of reactor 1506 in which
pressure, temperature, and mixing intensity are automatically
controlled and monitored. Reactor 1506 includes reactor block 1540,
which contains sealed reactor vessels 1542 for receiving reagents.
In one embodiment, reactor block 1540 is a single unit containing
each of reactor vessels 1542. Alternatively, reactor block 1540 can
include a number of reactor block modules, each of which contains a
number of reactor vessels 1542. Reactor 1506 includes a mixing
control and monitoring system 1544, a temperature control and
monitoring system 1546 and a pressure control and monitoring system
1548. These systems communicate with reactor control system
1500.
[0225] The details of mixing control and monitoring system 1544 are
illustrated in FIG. 55. Each of reactor vessels 1542 contains a
stirrer 1570 for mixing the vessel contents. In one embodiment,
stirrers 1570 are stirring blades mounted on spindles 1572 and
driven by motors 1574. Separate motors 1574 can control each
individual stirrer 1570; alternatively, motors 1574 can control
groups of stirrers 1570 associated with reactor vessels 1542 in
separate reactor blocks. In another embodiment, magnetic stirring
bars or other known stirring mechanisms can be used. System control
module 1508 provides mixing control signals to stirrers 1570
through interface 1576, 1578, and one or more motor cards 1580.
Interface 1576, 1578 can include a commercial motor driver 1576 and
motor interface software 1578 that provides additional high level
motor control, such as the ability to initialize motor cards 1580,
to control specific motors or motor axes (where each motor 1580
controls a separate reactor block), to set motor speed and
acceleration, and to change or stop a specified motor or motor
axis.
[0226] Mixing control and monitoring system 1544 can also include
torque monitors 1582, which monitor the applied torque in each of
reactor vessels 1542. Suitable torque monitors 1582 can include
optical sensors and magnetic field sensors mounted on spindles
1572, or strain gauges (not shown), which directly measure the
applied torque and transmit torque data to system control module
1508 and data analysis module 1514. Monitors 1582 can also include
encoders, resolvers, Hall effect sensors and the like, which may be
integrated into motors 1574. These monitors measure the power
required to maintain a constant spindle 1572 rotational speed,
which is related to applied torque.
[0227] Referring to FIG. 56, temperature control and monitoring
system 1546 includes a temperature sensor 1600 and a heating
element 1602 associated with each reactor vessel 1542 and
controlled by temperature controller 1604. Suitable heating
elements 1602 can include thin filament resistance heaters,
thermoelectric devices, thermistors, or other devices for
regulating vessel temperature. Heating elements can include devices
for cooling, as well as heating, reactor vessels 1542. System
control unit 1508 transmits temperature control signals to heating
elements 1602 through interface 1606, 1608 and temperature
controller 1604. Interface 1606, 1608 can include a commercial
temperature device driver 1606 implemented to use hardware such as
an RS232 interface, and temperature interface software 1608 that
provides additional high level communication with temperature
controller 1604, such as the ability to control the appropriate
communication port, to send temperature set points to temperature
controller 1604, and to receive temperature data from temperature
controller 1604.
[0228] Suitable temperature sensors 1600 can include thermocouples,
resistance thermoelectric devices, thermistors, or other
temperature sensing devices. Temperature controller 1604 receives
signals from temperature sensors 1600 and transmits temperature
data to reactor control system 1500. Upon determining that an
increase or decrease in reactor vessel temperature is appropriate,
system control module 1508 transmits temperature control signals to
heating elements 1602 through heater controller 1604. This
determination can be based on temperature parameters entered by the
user through user interface module 1516, or on parameters retrieved
by system control module 1508 from storage. System control module
1508 can also use information received from temperature sensors
1600 to determine whether an increase or decrease in reactor vessel
temperature is necessary.
[0229] As shown in FIG. 57, pressure control and monitoring system
1548 includes a pressure sensor 1630 associated with each reactor
vessel 1542. Each reactor vessel 1542 is furnished with a gas
inlet/outlet 1632 that is controlled by valves 1634. System control
module 1508 controls reactor vessel pressure through pressure
interface 1636, 1638 and pressure controller 1640. Pressure
interface 1636, 1638 can be implemented in hardware, software or a
combination of both. Pressure controller 1640 transmits pressure
control signals to valves 1634 allowing gases to enter or exit
reactor vessels 1542 through inlet/outlet 1632 as required to
maintain reactor vessel pressure at a level set by the user through
user interface 1516.
[0230] Pressure sensors 1630 obtain pressure readings from reactor
vessels 1542 and transmit pressure data to system control module
1508 and data analysis module 1514 through pressure controller 1640
and interface 1636,1638. Data analysis module 1514 uses the
pressure data in calculations such as the determination of the rate
of production of gaseous reaction products or the rate of
consumption of gaseous reactants, discussed in more detail below.
System control module 1508 uses the pressure data to determine when
adjustments to reactor vessel pressure are required, as discussed
above.
[0231] FIG. 58 is a flow diagram illustrating the operation of a
reactor control system 1500. The user initializes reactor control
system 1500 by setting the initial reaction parameters, such as set
points for temperature, pressure and stirring speed and the
duration of the experiment, as well as selecting the appropriate
hardware configuration for the experiment (step 1660). The user can
also set other reaction parameters that can include, for example, a
time at which additional reagents, such as a liquid co-monomer in a
co-polymerization experiment, should be added to reaction vessels
1542, or a target conversion percentage at which a quenching agent
should be added to terminate a catalytic polymerization experiment.
Alternatively, reactor control system 1500 can load initial
parameters from storage 1512. The user starts the experiment (step
1662). Reactor control system 1500 sends control signals to reactor
110, causing motor, temperature and pressure control systems 1544,
1546 and 1548 to bring reactor vessels 1542 to set point levels
(step 1664).
[0232] Reactor control system 1500 samples data through mixing
monitoring system 1544, temperature monitoring system 1546 and
pressure monitoring system 1548 at sampling rates, which may be
entered by the user (step 1666). Reactor control system 1500 can
provide process control by testing the experimental data, including
sampled temperature, pressure or torque values as well as elapsed
time, against initial parameters (step 1668). Based on these
inputs, reactor control system 1500 sends new control signals to
the mixing, temperature and/or pressure control and monitoring
systems of reactor 1506 (steps 1670, 1664). These control signals
can also include instructions to a material handling robot to add
material, such as a reagent or a catalyst quenching agent, to one
or more reactor vessels based upon experimental data such as
elapsed time or percent conversion calculated as discussed below.
The user can also enter new parameters during the course of the
experiment, such as changes in motor speed, set points for
temperature or pressure, or termination controlling parameters such
as experiment time or percent conversion target (step 1672), which
may also cause reactor control system 1500 to send new control
signals to reactor 1506 (steps 1672, 1670, 1664).
[0233] Data analysis module 1514 performs appropriate calculations
on the sampled data (step 1674), as will be discussed below, and
the results are displayed on monitor 1510 (step 1676). Calculated
results and/or sampled data can be stored in data storage 1512 for
later display and analysis. Reactor control system 1500 determines
whether the experiment is complete-for example, by determining
whether the time for the experiment has elapsed (step 1678).
Reactor control system 1500 can also determine whether the reaction
occurring in one or more of reactor vessels 1542 has reached a
specified conversion target based on results calculated in step
1674; in that case, reactor control system 1500 causes the addition
of a quenching agent to the relevant reactor vessel or vessels as
discussed above, terminating the reaction in that vessel. For any
remaining reactor vessels, reactor control system 1500 samples
additional data (step 1666) and the cycle begins anew. When all
reactor vessels 1542 in reactor block 1540 have reached a specified
termination condition, the experiment is complete (step 1680). The
user can also cause the reaction to terminate by aborting the
experiment at any time. It should be recognized that the steps
illustrated in FIG. 58 are not necessarily performed in the order
shown; instead, the operation of reactor control system 1500 can be
event driven, responding, for example, to user events, such as
changes in reaction parameters, or system generated periodic
events.
Analysis of Experimental Data
[0234] The type of calculation performed by data analysis module
1514 (step 1674) depends on the nature of the experiment. As
discussed above, while an experiment is in progress, reactor
control system 1500 periodically receives temperature, pressure
and/or torque data from reactor 1506 at sampling rates set by the
user (step 1666). System control module 1508 and data analysis
module 1514 process the data for use in screening materials or for
performing quantitative calculations and for display by user
interface module 1516 in formats such as those shown in FIG. 63-64
and 65.
[0235] Reactor control system 1500 uses temperature measurements
from temperature sensors 1600 as a screening criteria or to
calculate useful process and product variables. For instance, in
one implementation, catalysts of exothermic reactions are ranked
based on peak reaction temperature reached within each reactor
vessel, rates of change of temperature with respect to time, or
total heat released over the course of reaction. Typically, the
best catalysts of an exothermic reaction are those that, when
combined with a set of reactants, result in the greatest heat
production in the shortest amount of time. In other
implementations, reactor control system 1500 uses temperature
measurements to compute rates of reaction and conversion.
[0236] In addition to processing temperature data as a screening
tool, in another implementation, reactor control system 1500 uses
temperature measurement--combined with proper thermal management
and design of the reactor system--to obtain quantitative
calorimetric data. From such data, reactor control system 1500 can,
for example, compute instantaneous conversion and reaction rate,
locate phase transitions (e.g., melting point, glass transition
temperature) of reaction products, or measure latent heats to
deduce structural information of polymeric materials, including
degree of crystallinity and branching. For details of calorimetric
data measurement and use, see description accompanying FIG. 9 and
equations I-V.
[0237] Reactor control system 1500 can also monitor mixing
variables such as applied stirring blade torque in order to
determine the viscosity of the reaction mixture and related
properties. Reactor control system 1500 can use such data to
monitor reactant conversion and to rank or characterize materials
based on molecular weight or particle size. See, for example, the
description of equations VI-VIII above.
[0238] Reactor control system 1500 can also assess reaction
kinetics by monitoring pressure changes due to production or
consumption of various gases during reaction. Reactor control
system 1500 uses pressure sensors 1630 to measure changes in
pressure in each reactor vessel headspace--the volume within each
vessel that separates the liquid reagents from the vessel's sealed
cap. During reaction, any changes in the head space pressure, at
constant temperature, reflect changes in the amount of gas present
in the head space. As described above (equation XI), reactor system
1500 uses this pressure data to determine the molar production or
consumption rate, r.sub.i, of a gaseous component.
Operation of a Reactor Control System
[0239] Referring to FIG. 59, reactor control system 1500 receives
system configuration information from the user through system
configuration window 1700, displayed on monitor 1510. System
configuration window 1700 allows the user to specify the
appropriate hardware components for an experiment. For example, the
user can choose the number of motor cards 1580 and the set a number
of motor axes per card in motor pane 1702. Temperature controller
pane 1704 allows the user to select the number of separate
temperature controllers 1604 and the number of reactor vessels (the
number of feedback control loops) per controller. In pressure
sensor pane 1706, the user can set the number of pressure channels
corresponding to the number of reactor vessels in reactor 1506. The
user can also view the preset safety limits for motor speed,
temperature and pressure through system configuration window
1700.
[0240] As shown in FIG. 60, reactor control system 1500 receives
data display information from the user through system option window
1730. Display interval dialog 1732 lets the user set the refresh
interval for data display. The user can set the number of
temperature and pressure data points kept in memory in data point
pane 1734.
[0241] At any time before or during an experiment, the user can
enter or modify reaction parameters for each reactor vessel 1542 in
reactor block 1540 using reactor setup window 1760, shown in FIG.
61. In motor setup pane 1762, the user can set a motor speed
(subject to any preset safety limits), and can also select single
or dual direction motor operation. The user can specify temperature
parameters in temperature setup pane 1764. These parameters include
temperature set point 1766, turn off temperature 1768, sampling
rate 1770, as well as the units for temperature measurement and
temperature controller operation modes. By selecting gradient
button 1772, the user can also set a temperature gradient, as will
be discussed below. Pressure parameters, including a pressure set
point and sampling rate, can be set in pressure setup pane 1774.
Panes 1762, 1764 and 1774 can also display safety limits for motor
speed, temperature and pressure, respectively. The values
illustrated in FIG. 61 are not intended to limit this invention and
are illustrative only. Reactor setup window 1760 also lets the user
set a time for the duration of the experiment. Reactor setup window
1760 lets the user save any settings as defaults for future use,
and load previously saved settings.
[0242] FIG. 62 illustrates the setting of a temperature gradient
initiated by selecting gradient button 1772. In gradient setup
window 1800, the user can set a temperature gradient across reactor
1506 by entering different temperature set points 1802 for each
reactor block module of a multi-block reactor 1506. As with other
setup parameters, such temperature gradients can be saved in
reactor setup window 1760.
[0243] Referring to FIG. 63, the user can monitor an experiment in
reaction window 1830. System status pane 1832 displays the current
system status, as well as the status of the hardware components
selected in system configuration window 1700. Setting pane 1834 and
time pane 1836 display the current parameter settings and time
selected in reactor setup window 1760, as well as the elapsed time
in the experiment. Experimental results are displayed in data
display pane 1838, which includes two dimensional array 1840 for
numerical display of data points corresponding to each reactor
vessel 1542 in reactor 1506, and graphical display 1842 for color
display of the data points displayed in array 1840. Color display
1842 can take the form of a two dimensional array of reactor
vessels or three dimensional color histogram 1870, shown in FIG.
64. The color range for graphical display 1842 and histogram 1870
is displayed in legends 1872 and 1874, respectively. Data display
pane 1838 can display either temperature data or conversion data
calculated from pressure measurements as described above. In either
case, the displayed data is refreshed at the rate set in the system
options window 1730.
[0244] By selecting an individual reactor vessel 1542 in data
display pane 1838, the user can view a detailed data window 1900
for that vessel, as shown in FIG. 65. Data window 1900 provides a
graphical display of experimental results, including, for example,
temperature, pressure, conversion and molecular weight data for
that vessel for the duration of the experiment.
[0245] Referring again to FIG. 64, toolbar 1876 lets the user set
reactor parameters (by
[0246] entering reactor setup window 1760) and color scaling for
color displays 1842 and 1870. The user can also begin or end an
experiment, save results and exit system 1500 using toolbar 1876.
The user can enter any observations or comments in comment box
1878. User comments and observations can be saved with experimental
results.
[0247] Referring to FIG. 66, the user can set the color scaling for
color displays 1842 and 1870 through color scaling window 1920.
Color scaling window 1920 lets the user select a color range
corresponding to temperature or conversion in color range pane
1922. The user can also set a color gradient, either linear or
exponential, through color gradient pane 1924. Color scaling window
1920 displays the selected scale in color legend 1926.
[0248] The invention can be implemented in digital electronic
circuitry, or in computer hardware, firmware, software, or in
combinations of them. Apparatus of the invention can be implemented
in a computer program product tangibly embodied in a
machine-readable storage device for execution by a programmable
processor; and method steps of the invention can be performed by a
programmable processor executing a program of instructions to
perform functions of the invention by operating on input data and
generating output. The invention can be implemented advantageously
in one or more computer programs that are executable on a
programmable system including at least one programmable processor
coupled to receive data and instructions from, and to transmit data
and instructions to, a data storage system, at least one input
device, and at least one output device. Each computer program can
be implemented in a high-level procedural or object-oriented
programming language, or in assembly or machine language if
desired; and in any case, the language can be a compiled or
interpreted language.
[0249] Suitable computer programs in modules 1508 and 1514 can be
implemented in classes as set forth in the following tables. (The
prefix "o" in a name indicates that the corresponding property is a
user-defined object; the prefix "c" in a name indicates that the
corresponding property is a collection.)
1. Application Class
[0250] Property Table: TABLE-US-00001 Category Name Access
Description/Comments General ClsName Get Class name AppName Get
Application name sRootDir Get/Let Root directory of all system
files bDebugMode Get/Let System running mode. If TRUE, display
message boxes for errors in addition to error logging. If FALSE,
log the error to the log file DBIsConnected Get/Let Whether
database is connected System Registry SectionGeneral Get General
section SectionSystemLimits Get Section for System Limit Values
SectionDefaultParam Get Section for system default parameters
ColorScaling oTempScale Get Color Scale object for temperature data
oViscosityScale Get Color Scale object for viscosity data
oConversionScale Get Color Scale object for conversion data
oMWScale Get Color Scale object for molecule weight data
[0251] TABLE-US-00002 Name Argument List Return Type
Description/Comments SaveCnfg Boolean Save application
configurations to the system registry
2. ColorScale Class
[0252] Parent Class: Application
[0253] Property Table: TABLE-US-00003 Name Access
Description/Comments ClsName Get Class name Highest Get/Let Highest
value GradientType Get/Let Type of the gradient between the lowest
and highest to the log file LegendValues Get A collection of legend
values
[0254] Method Table: TABLE-US-00004 Name Argument List Return Type
Description/Comments SetLegendValues Recalculate the legend values
according to the current property values GetLegendColor fValue long
Get color of the specified data value
3. ColorLegend Class
[0255] Parent Class: ColorScale
[0256] Property Table: TABLE-US-00005 Name Access
Description/Comments ClsName Get Class Name ColorCount Get Number
of colors used in the legend
[0257] Method Table: TABLE-US-00006 Name Argument List Return Type
Description/Comments GetColorValue fValue long Get color for the
specified data value
4. System Class
[0258] Property Table: TABLE-US-00007 Category Name Access
Description/Comments General ClsName Get ExpID System Status Status
Get/Let Status variable STATUS_OFF Get constant STATUS_RUN Get
constant STATUS_IDLE Get constant STATUS_ERROR Get constant System
Timing oExpTiming Get Control and record the experiment time
oDisplayTiming Get Control the data display updating rate System
Alarming oAlarm Get Provide alarm when system error occurs System
oMotors Get Components oHeaters Get oPressures Get
[0259] Method Table: TABLE-US-00008 Name Argument List Return Type
Description/Comments Run StopRunning Archive
5. ExpTiming Class
[0260] Parent Class: System
[0261] Property Table: TABLE-US-00009 Name Access
Description/Comments ClsName Get Class Name TimingByTime Get/Let
Boolean type TimingByPressure Get/Let Boolean type
TimingByTemperature Get/Let Boolean type TargetTime Get/Let System
will stop if specified target value is achieved TargetPressure
Get/Let System will stop if specified target value is achieved
TargetTemperature Get/Let System will stop if specified target
value if achieved ExpDate Get/Let Date when experiment starts to
run ExpStartTime Get/Let Time when experiment starts to fun
ExpEndTime Get/Let Time when experiment stop running ExpElapsedTime
Get/Set The time passed during the experiment TimerInterval Let
Timer used to update the elapsed time
[0262] Method Table: TABLE-US-00010 Argument Name List Return Type
Description LoadDefaultExpTiming Boolean SaveDefaultExpTiming
Boolean
6. DisplayTiming Class
[0263] Parent Class: System
[0264] Property Table: TABLE-US-00011 Name Access
Description/Comments ClsName Get Class Name DisplayTimer Get/Set
Timer used to update the data TimerIntercal Get/Let
[0265] Method Table: TABLE-US-00012 Name Argument List Return Type
Description SaveDefaultParam Boolean Name Access
Description/Comments ClsName Get Class Name BeepTimer Set Timer
used to control beep PauseTimer Set Timer used to pause the beep
BeepStatus Get A boolean value: FALSE if paused, otherwise TRUE
BeepPauseTime Let Time duration for beep to pause
7. Alarm Class
[0266] Parent Class: System
[0267] Property Table:
[0268] Method Table: TABLE-US-00013 Name Argument List Return Type
Description TurnOnBeep Start to beep TurnOffBeep Stop beeping
BeepPause Disable beep BeepResume Enable beep
8. Motors Class
[0269] Parent Class: System
[0270] Property Table: TABLE-US-00014 Name Access
Description/Comments ClsName Get Class Name SpeedLimit Get/Let
Safety Limit MotorIsOn Get/Let Status variable Card1AxesCount
Get/Let Axes count in card1 Card2AcesCount Get/Let Axes count in
card2 oMotorCard1 Get Motor card object oMotorCard2 Get Motor card
object oSpinTimer Get/Set Timer for dual spin FoundDLL Get Motion
DLL ErrCode Get Error code
[0271] Method Table: TABLE-US-00015 Argument Return Category Name
List Type Description To/From LoadDefaultParam Boolean system
Registry SaveDefaultParam Boolean SaveCardAxesCount Boolean
SaveSystemLimit Boolean Create/ CreateCard1 iAxesCount Delete Card
Objects CreateCard2 iAxesCount DeleteCard1 DeleteCard2 Motor Init
Boolean For all axes Control Spin iAxis, Boolean dSpeed run Boolean
For all axes StopRunning Boolean For all axes Archive ArchiveParam
iFileNo Boolean
9. MotorAxis Class
[0272] Parent Class: Motors
[0273] Property Table: TABLE-US-00016 Name Access
Description/Comments ClsName Get Class Name Parent Set Reference to
the parent object MotorID Get/Let Motor Axis ID oCurParam Get
Reference to current parameter setting
[0274] Method Table: TABLE-US-00017 Argument Name List Return Type
Description GetParamSetting [index] MotorParam Return the last in
the parameter collection Run Boolean Add oCurParam to the Param
collection, and run this motor axis
10. MotorParam Class
[0275] Parent Class: Motors
[0276] Property Table: TABLE-US-00018 Name Access
Description/Comments clsName Get Class Name Parent Set Reference to
the parent object MotionType Get/Let Dual or single direction spin
DeltaT Get/Let Time duration before changing spin direction
SpinRate Get/Let Spin rate in RPM EffectiveTime Get/Let Time the
parameters take effect
[0277] Method Table: TABLE-US-00019 Name Argument List Return Type
Description PrintParam iFileNo Boolean Print the parameters to
file
11. Heaters Class
[0278] Parent Class: System
[0279] Property Table: TABLE-US-00020 Name Access
Description/Comments ClsName Get Class Name oParent Get Reference
to the parent object TempLimit Get/Let Temperature Safety Limit
SplRateLimit Get/Let Sample Rate Limit CtlrLoopCount Get/Let Loop
count in controller1 CtlrLoopCount Get/Let Loop count in
controller2 HeaterIsOn Get/Let Status variable oHeaterCtlr1 Get
Heater controller object as clsHeaterCtlr oHeaterCtlr2 Get Heater
controller object as clsHeaterCtlr oData Get Data object as
clsHeaterData 1DataPointsInMem Get/Let Number of data points kept
in memory FoundDLL Get RS232 DLL. If found, 1, otherwise -1 ErrCode
Get Error Code
[0280] Method Table: TABLE-US-00021 Argument Return Category Name
List Type Descriptions To/From LoadDefaultParam Boolean system
Registry SaveDefaultParam Boolean SaveCtlrLoopCount Boolean
SaveSystemLimit Boolean Create/ Create Ctlr 1 iLoopCount Delete
Ctlr Objects Create Ctlr 2 iLoopCount Delete Ctlr 1 Delete Ctlr 2
Heater Init Boolean Open Control COM1, COM2 OutputHeat Boolean For
all loops TurnOff Boolean For all loops GetTemp Boolean For all
loops SafetyMonitor lcount, Check vData Temperature SafetyHandler
Archive ArchiveParam iFileNo Boolean
12. HeaterCtlr Class
[0281] Parent Class: Heaters
[0282] Property Table: TABLE-US-00022 Name Access
Description/Comments ClsName Get Class Name Parent Set Reference to
the parent object oCurParam Get Reference to current parameter
setting
[0283] Method Table: TABLE-US-00023 Argument Name List Return Type
Description AddParamSetting oParam Boolean Add the parameter object
to the parameter collection GetParamSetting [index] HeaterParam
Return the last in the parameter collection
13. HeaterParam Class
[0284] Parent Class: HeaterCtlr
[0285] Property Table: TABLE-US-00024 Name Access
Description/Comments clsName Get Class Name Parent Set Reference to
the parent object Setpoint Get/Let Setpoint for temperature SplRate
Get/Let Sampling Rate (Hz) EffectiveTime Get/Let Time the
parameters take effect
[0286] Method Table: TABLE-US-00025 Name Argument List Return Type
Description PrintParam iFileNo Boolean Print the parameters to
file
14. HeaterData Class
[0287] Parent Class: Heaters
[0288] Property Table: TABLE-US-00026 Name Access
Description/Comments clsName Get Class Name Parent Set Reference to
the parent object DataPointsInMem Let LoopCount Let Total loop
count DataCount Get Data point count cTime Get Get time data
collection cTemp Get Get temperature data collection
[0289] Method Table: TABLE-US-00027 Name Argument List Return Type
Description GetData ByRef fTime, Boolean Get current data set, or
the ByRef vTemp data set with specified [, index] index AddData
fTime, vTemp Add the data set to the data collections ClearData
Clear the data collection WriteToDisk Write the current data to
disk file
15. Pressures Class
[0290] Parent Class: System
[0291] Property Table: TABLE-US-00028 Name Access
Description/Comments ClsName Get Class Name oParent Get Reference
to the parent object PressureLimit Get/Let Pressure Safety Limit
SplRateLimit Get/Let Sample Rate Limit ChannelCount Get/Let Analog
Input channel count PressureIsOn Get/Let Status variable oData Get
Data object as clsPressureData 1DataPointsInMem Get/Let Number of
data points kept in memory oCWAOP Get Object of analog output
ActiveX control oCWAIP Get Object of analog input ActiveX control
ErrCode Get Error code
[0292] Method Table: TABLE-US-00029 Argument Return Category Name
List Type Description To/From LoadDefaultParam Boolean System
Registry SaveDefaultParam Boolean SaveChannelCount Boolean
SaveDataPointsInMem SaveSystemLimit Boolean Pressure AnalogOutput
Boolean Output Pset System Control GetAlData Boolean Analog Input
Archive ArchiveParam iFileNo Boolean
16. PressureParam Class
[0293] Parent Class: Pressures
[0294] Property Table: TABLE-US-00030 Name Access
Description/Comments clsName Get Class Name Parent Set Reference to
the parent object Setpoint Get/Let Setpoint for pressure (psi)
SplRate Get/Let Sampling Rate (Hz) EffectiveTime Get/Let Time the
parameters take effect
[0295] Method Table: TABLE-US-00031 Name Argument List Return Type
Description PrintParam iFileNo Boolean Print the parameters to the
file
17. PressureData Class
[0296] Parent Class: Pressures
[0297] Property Table: TABLE-US-00032 Name Argument Access
Description/Comments clsName Get Class Name Parent Set Reference to
the parent object DataPointsInMem Let ChannelCount Let Total Al
channel count PresCount Get Pressure data point count ConvCount Get
Conversion data point count cPresTime Get Get time collection for
pressure data cPressure Get Get pressure data collection cConvTime
iChannelNo Get Get time collection for conversion data cConversion
iChannelNo Get Get conversion data collection
[0298] Method Table: TABLE-US-00033 Return Name Argument List Type
Description GetCurPres ByRef vPres Boolean Get current pressure
data set GetCurConv ByRef vConv Boolean Get current conversion data
set AddPres fTime, vPres Add the pressure data set to the pressure
data collections, then calculate conversions ClearData Clear all
the data collections WritePresToDisk Boolean Write the current
pressure data to disk file WriteConvToDisk Boolean Write the
current conversion data to disk file
18. ErrorHandler Class
[0299] Property Table: TABLE-US-00034 Name Access
Description/Comments ClsName Get Class Name LogFile Get/Let Log
file for error messages
[0300] Method Table: TABLE-US-00035 Argument Return Name List Type
Description SaveConfg Boolean OpenLogFile iFileNo Boolean Open log
file with specified file number for APPEND, lock WRITE OpenLogfile
iFileNo Boolean Open log file with specified file number for
APPEND, lock WRITE CloseLogFile LogError sModName, Write error
messages to the log sFuncName, file, also call DisplayError in
iErrNo, debug mode sErrText DisplayError sModName, Show message Box
to display sFuncName, the error iErrNo, sErrText
[0301] Suitable processors include, by way of example, both general
and special purpose microprocessors. Generally, a processor will
receive instructions and data from a read-only memory and/or a
random access memory. Storage devices suitable for tangibly
embodying computer program instructions and data include all forms
of non-volatile memory, including by way of example semiconductor
memory devices, such as EPROM, EEPROM, and flash memory devices;
magnetic disks such as internal hard disks and removable disks;
magneto-optical disks; and CD-ROM disks. Any of the foregoing can
be supplemented by, or incorporated in, ASICs (application-specific
integrated circuits).
[0302] To provide for interaction with a user, the invention can be
implemented on a computer system having a display device such as a
monitor or LCD screen for displaying information to the user and a
keyboard and a pointing device such as a mouse or a trackball by
which the user can provide input to the computer system. The
computer system can be programmed to provide a graphical user
interface through which computer programs interact with users.
[0303] An example of one such type of computer is shown in FIG. 67,
which shows a block diagram of a programmable processing system
1950 suitable for implementing or performing the apparatus or
methods of the invention. The system 1950 includes a processor
1952, a random access memory (RAM) 1954, a program memory 1956 (for
example, a writable read-only memory (ROM) such as a flash ROM), a
hard drive controller 1958, and an input/output (I/O) controller
1960 coupled by a processor (CPU) bus 1962. The system 1950 can be
preprogrammed, in ROM, for example, or it can be programmed (and
reprogrammed) by loading a program from another source (for
example, from a floppy disk, a CD-ROM, or another computer).
[0304] The hard drive controller 1958 is coupled to a hard disk
1964 suitable for storing executable computer programs, including
programs embodying the present invention, and data including the
images, masks, reduced data values and calculated results used in
and generated by the invention. The I/O controller 1960 is coupled
by means of an I/O bus 1966 to an I/O interface 1968. The I/O
interface 1968 receives and transmits data in analog or digital
form over communication links such as a serial link, local area
network, wireless link, and parallel link. Also coupled to the I/O
bus 1966 is a display 1970 and a keyboard 1972. Alternatively,
separate connections (separate buses) can be used for the I/O
interface 1966, display 1970 and keyboard 1972.
[0305] The invention has been described in terms of particular
embodiments. Other embodiments are within the scope of the
following claims. Although elements of the invention are described
in terms of a software implementation, the invention may be
implemented in software or hardware or firmware, or any combination
of the three. In addition, the steps of the invention can be
performed in a different order and still achieve desirable
results.
[0306] Moreover, the above description is intended to be
illustrative and not restrictive. Many embodiments and many
applications besides the examples provided will be apparent to
those of skill in the art upon reading the above description. The
scope of the invention should therefore be determined, not with
reference to the above description, but should instead be
determined with reference to the appended claims, along with the
full scope of equivalents to which such claims are entitled. The
disclosures of all articles and references, including patent
applications and publications, are incorporated by reference for
all purposes.
* * * * *