U.S. patent number 3,841,059 [Application Number 05/292,146] was granted by the patent office on 1974-10-15 for compressed and thermostated air regulated gas liquid chromatography oven with simultaneously operated multiple chromatography columns.
Invention is credited to William C. McCabe.
United States Patent |
3,841,059 |
McCabe |
October 15, 1974 |
COMPRESSED AND THERMOSTATED AIR REGULATED GAS LIQUID CHROMATOGRAPHY
OVEN WITH SIMULTANEOUSLY OPERATED MULTIPLE CHROMATOGRAPHY
COLUMNS
Abstract
The apparatus of the present invention comprises a multiple
column gas liquid chromatographic, GLC, oven assymbly for
chromatographing a plurality of samples simultaneously. Each of a
plurality of GLC columns is contained in a separate small oven
whose temperature is independently regulated using a controled flow
of compressed and thermostated dry air. Segments of the effluent
gas from each of a plurality of GLC columns is passed individually
and sequentially to a single detector using a single valve with
multiple symmetrically spaced inlets but only two outlets. The
effluent gas from all of the GLC columns but one is passed to waste
while the effluent gas from one GLC column is passed to a common
detector. The valve is repositioned to sequentially pass the
effluent gas from each of a plurality of GLC columns to a single
detector. The use of a single small valve is made possible by the
use of a plurality of micro ovens for individual temperature
control of each of a plurality of GLC columns. The use of micro
ovens is made possible by the use of compressed and thermostated
air as a source of heat for each GLC column oven. This simultaneous
operation of a plurality of GLC columns results in a significant
increase in the rate of GLC analysis for a plurality of
samples.
Inventors: |
McCabe; William C. (Wichita,
KS) |
Family
ID: |
23123425 |
Appl.
No.: |
05/292,146 |
Filed: |
September 25, 1972 |
Current U.S.
Class: |
96/102;
96/104 |
Current CPC
Class: |
G01N
30/30 (20130101); G01N 2030/628 (20130101); G01N
30/466 (20130101); G01N 30/20 (20130101); G01N
2030/3084 (20130101) |
Current International
Class: |
G01N
30/00 (20060101); G01N 30/30 (20060101); G01N
30/02 (20060101); G01N 30/62 (20060101); G01N
30/46 (20060101); G01N 30/20 (20060101); B01d
015/08 () |
Field of
Search: |
;210/31C,198C
;55/197,67,386 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Adee; John
Claims
I claim:
1. An apparatus for performing simultaneous gas liquid
chromatographic analyses on a plurality of samples comprising a
plurality of micro ovens, a chromatography column contained in each
of said ovens, said columns having an inlet and outlet means, said
inlet having separate conduit means for sample and carrier gas,
said outlet having a single conduit means for sample and carrier
gas, a segment of conduit means for said carrier gas contained in
each of said ovens and connected to the inlet of each of said
chromatography columns; a valve assymbly contained in an insulated
chamber having an aperature to each of said ovens, said valve
assymbly having a plurality of inlets connected by conduit means to
the outlet of each of said columns, said valve means containing
passage means sequentially connecting one of said columns to a
detector means and the other of said columns to a waste outlet
means; a chromatography column micro oven, compressed air heating
means comprising a tank for holding compressed and thermostated air
with a plurality of outlets each connected to one of said ovens, an
air temperature and pressure regulating means for said compressed
air tank and a plurality of air flow regulating means in the said
connections between said tank and each of said ovens.
2. The apparatus of claim 1, wherein the segment of conduit means
for said carrier gas comprises a length of folded carrier gas
conduit tubing located inside each chromatography column micro oven
and connected to the inlet of each chromatography column.
3. The apparatus of claim 2, wherein the length of folded carrier
gas conduit tubing located inside each chromatography column micro
oven serves to preheat said carrier gas to the temperature of the
said micro oven prior to said carrier gas entering said
chromatography column.
4. The apparatus of claim 1, wherein the micro ovens are each just
large enough to contain one chromatography column, a length of
folded carrier gas tubing and just sufficient free space for
circulation of compressed and thermostated air.
5. The apparatus of claim 1, wherein the valve assymbly having a
plurality of inlets connected by conduit means to the outlet of
each of said columns is adjustable to pass a portion of the column
effluent carrier gas from each of a plurality of chromatography
columns sequentially to a detector means while passing the effluent
carrier gas from all other said columns to waste.
6. The apparatus of claim 1, wherein the insulated chamber for the
said column effluent gas valve assymbly contains conduit means for
circulation of said compressed and thermostated air around said
valve assymbly comprising an aperature to each of said micro ovens
and a single exhaust outlet.
7. The apparatus of claim 1, wherein the air temperature and
pressure regulating means for said compressed air tank comprises a
temperature sensing probe, a heating means, a cooling means, a
temperature regulator means and an inlet from a compressed air
source.
8. The apparatus of claim 7, wherein the inlet from a compressed
air source contains a pressure regulating means which functions to
open or close said inlet depending on the pressure inside said
compressed and thermostated air tank and the pressure set on said
pressure regulating means.
9. The apparatus of claim 1, wherein the air flow regulating means
between said tank and each of said ovens comprises an air flow
regulator valve, a motor-gear drive means to automatically open and
close the said air flow regulator valve at one of several preset
rates, each corresponding to a different rate of temperature
increase inside said chromatography column micro oven, a mechanical
stop means to disengage the said automatic motor-gear drive means
from the said air flow regulator valve and a separate electrical
feedback means to reverse the motor of each said air flow regulator
valve motor-gear drive means depending on whether the temperature
of the chromatography column is less or greater than the
temperature set on a chromatography column temperature regulator
means.
10. The apparatus of claim 9, wherein the electrical feedback means
for each said air flow regulator valve motor-gear drive means
comprises a motor-gear drive means which functions to vary a
thermostat set temperature at various preset rates, a
chromatography column temperature sensing probe connected by
suitable conduit means to said thermostat, a suitable conduit means
between said thermostat means and said air flow regulator valve
drive motor, a suitable relay means contained in said conduit means
between said thermostat means and said valve drive motor.
11. The apparatus of claim 10, wherein the suitable relay means
functions to reverse the electrical current to the said air flow
regulator valve drive motor depending on whether the temperature of
the effluent carrier gas from said chromatography column is greater
or less than the said thermostat means set temperature.
Description
BACKGROUND OF THE INVENTION
In any forced air oven system the critical parameters important for
temperature regulation of the same type. They are: (1) the amount
of heat absorbed by the oven itself and the material being heated
inside the oven, (2) the heat lost from the oven due to imperfect
oven insulation, (3) the temperature of the air circulated in the
oven, and (4) the rate of flow of thermostated air in or through
the oven. Most oven systems rely on changes in parameter (3), air
temperature, for regulation of oven temperature. In this type of
oven system parameters (1), (2), and (4) are held essentially
constant. The system for oven temperature regulation contained in
the present invention uses an entirely different principle. It
maintains parameters (1), (2), and (3) essentially constant and
varies parameter (4), the rate of flow of thermostated dry air
through the oven. This air flow regulation is attained using a
separately maintained source of compressed and thermostated dry air
with a partially manually and partially automatically operated
variable gas flow valve for each of a plurality of GLC column
ovens. By using compressed and thermostated air and an air flow
regulator valve it is possible to reduce the size of each of a
plurality of GLC column ovens considerably, which greatly reduces
heat loss due to parameter (1). With these micro ovens a plurality
of them can be maintained individually in a very small space
allowing the use of a single valve for regulating the flow of each
column effluent gas to a common detector. In fact, the multiple
column effluent gas micro regulating valve, contained in the
present invention, cannot be used effectively without the micro GLC
column ovens, which in turn requires the use of compressed air for
temperature regulation.
Gas liquid chromatography has been established as a superior means
for doing an almost limitless number of difficult organic analyses.
The oven systems which are presently available, however, do not
allow analytic results to be obtained at a practical rate; in some
cases it might take up to two hours for a single analysis. This
usual slow rate of operation has greatly restricted the use of GLC
in the routine analytical laboratory and has tended to exclude it
almost entirely from the clinical chemistry analytical lab where
their volume of work is relatively large and most of the results
are needed quickly. The oven system described in the present
invention allows a plurality of GLC analyses to be run
simultaneously and therefore increases the rate of analysis by an
order of magnitude over other types of oven systems. This striking
increase in rate of analysis which is attained with the present
invention represents a significant innovation in GLC column oven
design. In the case of most routine GLC analyses, only one or a
small number of components in a mixture is important in the
analysis. The majority of the components in a sample are not
important and therefore most of the effluent gas from a GLC column
need not be passed to a detector for quantitation. For a given
sample analysis, there are usually components coming off the GLC
column before and after the component or components of interest
which could be excluded from the detector and, therefore, from
quantitation. All of the present oven systems for GLC analysis must
quantitate all components in a given sample and the time spent
quantitating components which are not important in the analysis
represents a significant increase in the overall time of analysis
for each sample and therefore a striking decrease in the rate of
sample analysis for a given GLC instrument. The apparatus of the
present invention is designed to eliminate this unnecessary
increase in analytical time. In the case of the present invention
only those components of a sample which are important for the
analysis are passed to the detector for quantitation while most of
the other components are passed to waste. Because the number of
components quantitated is small compared to the total number of
components in the sample being analyzed, there is a tremendous
savings in analytical time and therefore an increase in the rate of
analysis by almost an order of magnitude for most samples
analyzed.
SUMMARY OF THE INVENTION
An object of the present invention is to increase the rate of gas
liquid chromatography, GLC, analysis by the simultaneous operation
of a plurality of GLC columns.
Another object of the present invention is to run a plurality of
GLC analyses simultaneously using only a single detector system by
means of a single micro valve which passes a segment of the
effluent gas from each of a plurality of GLC columns individually
and sequentially to the detector.
Another object of the present invention is to use a plurality of
micro GLC column ovens, each individually thermostated for constant
temperature operation and/or variable temperature operation, in a
small space to enable a single micro valve with multiple
symmetrically spaced inlets and outlets to either the detector or
to waste to be used to sequentially pass a segment of the effluent
gas from each of a plurality of GLC columns to a single
detector.
Another object of the present invention is to use compressed and
thermostated dry air for regulating the oven temperature for each
of a plurality of micro GLC column ovens with limited free space
for air entrance and circulation.
Another object of the present invention is to provide a plurality
of micro GLC column ovens with a common source of compressed and
thermostated dry air using a compressed air source with its outlet
side attached to a metal tank with interposed moisture trap and
appropriate pressure valves to maintain a constant, but adjustable,
tank pressure, a metal tank built to withstand the necessary
operating temperature and pressure of the dry air and containing a
heating means, a cooling means, a temperature sensing probe, inlet
for dry air from the compressed air source and outlets for each of
the micro GLC column ovens.
Another object of the present invention is to provide a temperature
regulator means for the compressed air tank which will function to
open or close the electric circuit to either the heating or cooling
means depending on the preset temperature and the temperature
inside the compressed air tank as indicated by a temperature
sensing probe.
Another object of the present invention is to provide each micro
GLC oven with a partially manually operated and partially
automatically operated gas flow regulator valve to control the flow
of compressed and thermostated dry air into each of a plurality of
GLC column micro ovens.
Another object of the present invention is to provide each micro
GLC column oven gas flow regulator valve with a reversible motor
and gear drive means to regulate the rate at which the valve is
opened or closed which determines the rate of flow of thermostated
dry air into each GLC column oven which, in turn, determines the
temperature inside each oven.
Another object of the present invention is to provide each micro
GLC column oven with a temperature regulator means which comprises
a set temperature indicator associated with a motor-gear drive
means to enable the set temperature to be altered at variable
rates, degrees per minute, a temperature sensing probe inside each
GLC column oven, a GLC column oven temperature indicator, and a
means to reverse the current to the air flow regulator reversible
drive motor depending on whether the GLC column oven temperature is
less or greater than the set temperature.
Another object of the present invention is to place the GLC column
micro oven temperature sensing probe for each oven in contact with
the GLC column effluent gas.
Another object of the present invention is to provide each GLC
column micro oven gas flow valve motor-gear means with a mechanical
stop to prevent the valve from being opened past a preset point and
thus prevent the oven from being heated beyond a given final
temperature.
Another object of the present invention is to provide a means for
preheating the carrier gas for each GLC column inside the GLC
column micro oven before the carrier gas inters the GLC column.
Other objects and further scope of applicability of the present
invention will become apparent from the detailed description given
hereinafter; it should be understood, however, that the detailed
description and specific examples, while indicating preferred
embodiments of the invention, are given by way of illustration
only, since various changes and modifications within the spirit and
scope of the invention will become apparent to those skilled in the
art from this detailed description.
The general, overall operation of the apparatus of the present
invention can be defined as follows. The gas flow regulator valves
to the GLC column micro ovens are closed manually. The appropriate
compressed air tank pressure is set on the tank pressure gauge and
the pressure release gauge is set slightly higher than the tank
pressure. The conduit means between the compressed air source and
the tank is opened. The compressed air tank temperature regulator
is set to heat or cool as required. The proper compressed air tank
operating temperature is set on the thermostat and the switch
connecting the compressed air tank temperature regulator to line
voltage is turned on. As soon as the compressed air tank has
reached the proper operating temperature and pressure, the
automated drive means for each air flow regulator valve is
disengaged and each GLC column oven gas flow regulator valve is
manually opened a slight amount. The column effluent gas valve is
set to pass the effluent gas from column one to the detector and
the carrier gas valve for each GLC column is opened and its proper
flow rate is set. Each air flow regulator valve is opened manually
until the proper final oven temperature is maintained by each oven
as indicated by the temperature indicator means for each GLC column
micro oven. The mechanical stop pins for each flow regulator valve
automated opening drive means are now set. The mechanical stop pin
is placed into the proper hole of the mechanical stop drive wheel
to force the air flow regulator valve drive gear means to disengage
when this amount of rotation of the mechanical stop drive wheel has
occurred. Now each flow valve is manually closed until the
temperature for each GLC column oven holds at the proper initial
operating temperature. A second pin is placed in the mechanical
stop wheel of each air flow regulator valve drive means to mark
this position for subsequent resetting. The set temperature
indicator on each GLC column oven temperature programming
thermostat is disengaged and moved to indicate the initial
operating temperature and a mechanical stop is positioned at a
position equivalent to the final operating temperature. The set
temperature indicator on the temperature programming thermostat
will then stop when it reaches the final operating temperature
setting. The means for manually disengaging the automated drive
assymbly for each air flow regulator valve is released. The
variable speed gear box for both the air flow regulator valve drive
means and the temperature programming drive means for each GLC
column oven are set for the proper rate of temperature rise. Now
each GLC column oven variable temperature programming means and
sample injection will be started in a delayed sequence. The line
voltage switch for the GLC column oven temperature programming
means for column one will be turned on and a sample injected into
column one, then after a given time interval the switch for column
two will be turned on and a sample injected into column two and the
procedure continued until all columns have been started. As soon as
that portion of the component peaks separated by column one which
are to be quantitated start reaching the detector the time interval
for injection of samples is repeated for timing the turning of the
GLC column effluent gas valve from column one to column two and so
forth until a segment of the effluent gas from each GLC column has
been quantitated.
To convert from variable temperature operation to constant
temperature operation just set each temperature programming
variable speed gear box to zero rate of change and repeat the
remaining steps listed above.
The partially manual and partially electronic means of regulating
the rate of opening of each air flow regulator valve described in
the present invention is just one of many possible means, some
being totally automated, for regulating the rate of opening of an
air flow regulator valve to achieve a programmed variable
temperature operation of a GLC column oven. Substitution of any one
of the other possible means would not change the basic principle of
GLC column oven temperature regulation which depends on the control
of the flow of compressed and thermostated gas, air in this case,
into an oven, a micro oven in this case, described in the present
invention.
There are a number of different means of obtaining and/or
maintaining compressed and thermostated gas for regulating the
temperature of a GLC column oven, but none of these alternate means
would constitute a change in the basic principle of using
compressed and thermostated gas to heat a GLC column oven as
described in the present invention.
There are a number of different valve designs similar to the GLC
column effluent gas valve described as part of the present
invention but none of these would alter the basic principle of a
plurality of GLC column effluent gas inlets and outlets to either
waste or the detector and with the capability of sequentially
passing a small segment of the total gas effluent from each of a
plurality of columns to a single detector as described in the
present invention.
The drawings and descriptions presented hereinafter and above which
specify a given GLC column micro oven system with a set number of
GLC column micro ovens is presented simply to illustrate the basic
characteristics of the present invention. Certainly any number of
micro ovens could be used in actual practice and would only
constitute additional embodiments of the apparatus described in the
present invention.
There are a variety of analytic modes of operation for the GLC oven
assymbly described in the present invention but in all cases the
basic principle is the same. Only that portion of the effluent gas
from each of a plurality of GLC columns which is important in the
analysis of a sample is passed to the detector for final
quantitation. By operating a plurality of columns essentially
simultaneously one is able to reduce the time of analysis for any
GLC column system, reguardless of total run time for a given sample
on the column, to just that segment of time necessary to quantitate
the component or components of interest. With this GLC oven system,
except for the first and last GLC columns, one no longer needs to
wait for components running before or after that component to be
quantitated to clear the detector. One simply passes the effluent
gas from each of a plurality of columns to the detector only when a
component or components of interest is coming off the columns. This
column effluent valving system has no direct affect on the
separation of components of a sample on the GLC column and also has
no affect on the detector operation. The valving system illiminates
time spent quantitating those components which are of little or no
interest in the analysis of a sample. With this valving system, the
effective time of GLC analysis for each sample is reduced by an
order of magnitude in most cases. The column effluent valving
assymbly described in the present invention is a means for
increasing the rate of analysis but has no significant qualitative
affect on the gas liquid chromatographic analysis of a sample.
DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the
detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only and thus are
not limitative of the present invention and wherein,
FIG. 1 shows a schematic representation of the invention with the
oven assymbly in exploded perspective;
FIG. 2 shows a schematic diagram of the oven temperature
programming means;
FIG. 3 shows an exploded perspective view of the GLC column
effluent gas valve assymbly; and
FIG. 4 shows a longitudinal section view of the GLC column effluent
gas valve assymbly of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The gas liquid chromatography, GLC, column oven apparatus of the
present invention according to FIG. 1 comprises a GLC column
effluent gas valve assembly 1 which includes a female valve seat 2
containing a plurality of inlet holes 3 symmetrically spaced around
the valve seat. Each of the inlet holes 3 are connected by
appropriate conduit means 4 to the outlet side of one of a
plurality of GLC columns 5. The effluent gas from each GLC column
passes through a conduit means 4 and into the valve at one of the
inlet holes 3. The effluent gas from one of a plurality of columns
is passed to the bottom of the valve assymbly and out the detector
outlet hole 6. The effluent gas from the remainder of the GLC
columns passes through the inlet holes in the wall of the female
valve seat and through matching holes in the wall of the male valve
seat 7 to the hollow center of the male valve seat and up through
the hollow rod 8 to waste. The male valve seat 7 can be rotated
around rod 8 as its axis to sequentially pass a segment of the
effluent gas from each of a plurality of GLC columns through the
detector outlet 6 to a single detector means not shown in the
drawings. The GLC column effluent gas valve assymbly 1 is contained
within an insulated chamber comprising a top piece 9, a middle
piece 10, and a bottom piece 11. The bottom piece 11 of the valve
chamber has an outlet 12 in the bottom for the conduit means
connecting the valve detector outlet 6 with the detector. The
middle piece 10 of the valve chamber has a plurality of flanges 13
symmetrically spaced around the chamber for attachment of an equal
number of GLC column assymblies 14. Each GLC column assymbly 14
comprises a length of carrier gas conduit tubing 15 which is
connected at one end to a source of compressed carrier gas, not
shown in the drawings, and at the other end to a standard combined
carrier gas-sample inlet means 16. The carrier gas conduit tubing
15 is folded to fill the space between the inlet and outlet sides
of the GLC column 5 to preheat the carrier gas before it inters the
GLC column. Each GLC column 5 is connected to the valve chamber
middle piece flange 13 at the carrier gas inlet side by means of
the standard combined carrier gas-sample inlet means 16 and at the
effluent gas outlet side by standard tube fitting means 17. The GLC
column micro oven temperature sensing probe 18 is attached inside
tube fitting means 17 to monitor the temperature of the GLC column
effluent gas. The hot oven air in the vicinity of the folded
carrier gas conduit tubing 15 and GLC column 5 passes from the GLC
column micro oven through the small orifice 19 and into the valve
chamber. There is an exhaust outlet 20 for the hot air in the
bottom of the valve chamber bottom piece 11. The path of the hot
air is indicated by the arrows. The circulation of hot air from
each of the GLC column micro ovens through the valve chamber serves
to maintain the valve assymbly 1 at approximately the average
temperature of the plurality of GLC column micro ovens. Each of the
GLC columns 5 and its carrier gas conduit tubing 15 fits inside a
GLC column micro oven 21. Each oven 21 is attached by suitable
conduit means to a common tank 22 of compressed and thermostated
air through an air flow regulator valve 23. The air pressure inside
tank 22 is maintained by a source of compressed air 24 and a
pressure regulator valve 25 and a pressure release valve 26. The
temperature of the air in tank 22 is maintained by a temperature
regulating means comprising a heating means 27, a cooling means 28,
a temperature sensing probe 29, and a thermostat 30. The
temperature sensing probe 29 and thermostat 30 are connected by
suitable electrical means 31. Each air flow regulator valve 23 can
be controled manually using knob 32 or automatically by means shown
in FIG. 2. The temperature inside each of a plurality of micro
ovens 21 is controled by the amount of thermostated air flowing
into each oven through one of a plurality of air flow regulator
valves 23.
FIG. 2 shows a schematic illustration of one of a plurality of
automatic means for controling each of the air flow regulator
valves 23 associated with each of a plurality of GLC column micro
ovens 21. It comprises a clutch assymbly 33, a variable speed
motor-gear drive means 34, and a temperature programming means 35.
The clutch assymbly 33 is associated with the air flow regulator
valve 23 by suitable gear means 36 and to the motor-gear drive
means 34 by drive gear 37. Clutch assymbly 33 comprises a primary
drive gear means 38 which is held in contact with gear means 36 by
rod 39 and spring 40. Gear means 38 can be disengaged manually from
gear means 36 by pulling out rod 39 and moving pin 41 to the
forward hole shown in rod 39. In this position the air flow
regulator valve 23 can be operated manually using knob 32. Gear
means 38 drives gear means 36 which drives the air flow regulator
valve 23 open or closed and also turns gear 42. Gear 42 is attached
to wheel 43 which turns as gear 42 turns. Wheel 43 has a plurality
of pin holes evenly spaced around its circumference. Pins 44 can be
placed in wheel 43 and these pins will contact rod 39 whenever
wheel 43 has rotated into the proper position as shown in FIG. 2.
Whenever pin 44 contacts rod 39 it pushes both rod 39 and the
attached gear means 38 back against spring 40 which causes gear
means 38 and 36 to disengage and thus stops the automatic opening
of the air flow regulator valve 23. By placing pin 44 in the proper
hole in wheel 43 the automatic opening of the air flow regulator
valve 23 can be stopped at any point between fully closed and fully
open. The variable speed motor-gear drive means 34 comprises a
reversible motor 45 which drives gear 37 through a variable speed
gear box 46. The rate of rotation of drive gear 37 can be varied by
changing gears in gear box 46. Different rates of rotation of gear
37 represent different rates of opening of the air flow regulator
valve 23 corresponding, approximately, to different rates of rise
of temperature in the corresponding GLC column micro oven 21. The
direction motor 45 turns and therefore whether the air flow
regulator valve 23 is being opened or closed is controled by the
temperature programming means 35 which comprises a relay 47
connected to motor 45 by means 48 and to thermostat 49 by means 50.
Thermostat 49 has a temperature indicator 51 associated with the
GLC column micro oven temperature sensing probe 18 by means 52 and
a set temperature indicator 53 which can be set manually or driven
automatically by gear 54, belt drive 55, gear 56, variable speed
gear box 57, and motor 58. Relay 47 and motor 58 are connected to a
power source by electrical means 59 and 60 through switch 61. The
position of the set temperature indicator 53 can be varied
automatically from some manually set initial temperature to a
predetermined final temperature setting by rotation of the gear
means 55, 56, and 57. The rate of change of the set temperature
indicator setting in degrees per minute is determined by the
arrangement of gears in the variable speed gear box 57 which
determines the rate of rotation of gear 56. When the temperature
indicator 51 is at a lower temperature than the set temperature
indicator 53 the current from relay 47 to reversible motor 45 is
such that the air flow regulator valve 23 is driven open. When
indicator 51 is at a higher temperature than indicator 53 the
current from relay 47 is reversed and motor 45 drives the air flow
regulator valve 23 closed.
FIGS. 3 and 4 show an exploded perspective view and a longitudinal
section view of the GLC column effluent gas valve assymbly. FIG. 3
comprises a lever 62 which can be rotated in a vertical plane to
seat and unseat the valve or in a horizontal plane to reposition
the male valve seat to sequentially pass a segment of the effluent
gas from each of a plurality of GLC columns to a single detector.
Lever 62 is attached by pin 63 to hollow rod 8 which serves both as
a means for repositioning the male valve seat 7 which includes wall
64 and as a waste gas conduit means from the valve assymbly. The
effluent gas from all but one of the GLC columns is passed to waste
through hollow rod 8. The male and female halves of the valve seat
are forced together by spring 65 pressing against spring support 66
which is attached to rod 8. Rod 8 is held in proper vertical
position by guide 67 which is attached to the top flange 68 of the
female portion of the valve seat 2. The top flange 68 of the female
valve seat 2 has a plurality of GLC column effluent gas inlet holes
69 symmetrically spaced around the valve seat and an outlet 70,
shown in FIG. 4, to the detector at the bottom. The wall 64 of the
male valve seat 7 also has a plurality of GLC column effluent gas
inlet holes 71 symmetrically spaced around the valve seat with one
replaced by a narrow grove 72 on the outside which connects one of
the inlet holes 69 in the female valve seat 2 to the detector
outlet hole 70. The inlet holes 69 and 71 in the female and male
valve seats are spaced so they exactly match. The effluent gas from
all of the GLC columns but one pass to the center of the valve
assymbly through holes 69 and 71 in the female and male valve seat
walls and on to waste through the hollow rod 8.
FIG. 4 shows the two alternate paths for the GLC column effluent
gas as indicated by the arrows. For the effluent gas from the GLC
column being passed to the detector, the effluent gas inters the
female valve seat 2 through inlet 74 and hole 69 in flange 68,
passes to the bottom of the valve assymbly down grove 72 between
walls 64 and 73 along path 75 as indicated by the arrows. It passes
through hole 70 in the bottom of the valve assymbly and out of the
bottom of the female valve seat 2 through the detector outlet 6
along path 76 as indicated by the arrow. The effluent gas from each
of the remaining GLC columns is passed by similar routes to waste.
The effluent gas from this plurality of columns inters the female
valve seat 2 through a plurality of inlets 77, passes to the center
of the valve assymbly through a matching set of inlet holes 71 in
the wall 64 of the male valve seat 7 and along path 78 as indicated
by the arrows up through the hollow rod 8 to waste along path 79
indicated by the arrow. Rod 8 is held in a vertical position by
guide 67 which is attached to the female valve seat 2.
* * * * *