U.S. patent application number 13/416818 was filed with the patent office on 2012-07-12 for laboratory syringe pumps.
Invention is credited to Richard K. Bennett, Mark Davis, Bruce H. Edwards, Andrew J. McKenna, Justin M. Piccirillo, Ron Y. Sostek.
Application Number | 20120177507 13/416818 |
Document ID | / |
Family ID | 42936534 |
Filed Date | 2012-07-12 |
United States Patent
Application |
20120177507 |
Kind Code |
A1 |
Bennett; Richard K. ; et
al. |
July 12, 2012 |
LABORATORY SYRINGE PUMPS
Abstract
A syringe pump which includes a pusher block is slidably mounted
on bearings on one or more guide rails. The pusher block is
advanced or retracted by a lead screw having an axis which is
offset from the axis of the one or more guide rails which are
supported at their respective ends by support blocks, wherein
forward and/or trailing sides of the pusher block bearings are
extended, and wherein the guide rail support blocks include
recesses for accommodating the extended ends of the pusher block
slide bearings. In another embodiment, the syringe pump includes
quick connect-disconnect fixtures for loading and unloading
syringes. Other mechanical and programmable improvements are
described in the specification.
Inventors: |
Bennett; Richard K.;
(Winchester, NH) ; Davis; Mark; (Millville,
MA) ; Edwards; Bruce H.; (Marlborough, MA) ;
McKenna; Andrew J.; (Warwick, RI) ; Piccirillo;
Justin M.; (Uxbridge, MA) ; Sostek; Ron Y.;
(Newton, MA) |
Family ID: |
42936534 |
Appl. No.: |
13/416818 |
Filed: |
March 9, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12755245 |
Apr 6, 2010 |
|
|
|
13416818 |
|
|
|
|
61167071 |
Apr 6, 2009 |
|
|
|
Current U.S.
Class: |
417/53 ;
417/410.1 |
Current CPC
Class: |
A61M 5/1456 20130101;
A61M 2005/14573 20130101; A61M 2205/52 20130101; Y10T 137/0324
20150401; A61M 2205/50 20130101; A61M 2205/60 20130101; B01L 3/00
20130101 |
Class at
Publication: |
417/53 ;
417/410.1 |
International
Class: |
F04B 49/06 20060101
F04B049/06; F04B 35/04 20060101 F04B035/04 |
Claims
1-7. (canceled)
8. A system of syringe pumps comprising a master pump and one or
more satellite syringe pumps, wherein the satellite syringe pumps
are controlled and powered by the master pump, and wherein
electrical power and controls for operation of the one or more
satellite pumps are distributed from the master pump.
9. The system of syringe pumps as claimed in claim 8, wherein the
master pump includes a control system having a memory for storing
run protocols.
10. A method for maintaining smooth and consistent flow rates to
and from a syringe pump, which comprises output from at least two
syringes into a single flow channel, and operating the at least two
syringes in a coordinated and sequential order in order to maintain
a consistent flow rate or pressure.
11. The method of claim 10, and including removing and replacing or
refilling one of the syringe pumps while the other or others are
dispensing or withdrawing fluid at a predetermined flow rate.
12. The method of claim 11, wherein the syringes dispense fluid at
a constant volume flow rate, or constant pressure or constant
force.
13. The method of claim 11, wherein the syringes withdraw fluid at
constant volume flow rate, or constant pressure, or constant
force.
14. A method of operating one or more syringe pumps which comprises
pulsing the syringe pumps to mimic physiologic characteristics.
15. The method of claim 14, wherein the physiological
characteristic comprises an EKG.
16. The method of claim 15, wherein the physiological
characteristic mimics blood flow.
17-20. (canceled)
21. A method for controlling a syringe pump, which comprises
comparing actual syringe movement to a theoretical desired value,
and adjusting said syringe movement to approximate said theoretical
value.
22. The method of claim 21, wherein said syringe is moved by a
screw mechanism, and including the step of adjusting rotation of
said screw.
23. The method of claim 22, wherein said screw profile is
determined by one or more encoders.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from U.S. Provisional
Application Ser. No. 61/167,071 filed Apr. 6, 2009.
FIELD OF THE INVENTION
[0002] The present invention relates generally to syringe pumps,
and more particularly improvements in syringe pumps. The invention
has particular utility in connection with syringe pumps for
laboratory or general fluidics transfer of gas and liquids use,
e.g. for conducting small scale chemical reactions, liquid sample
preparation for high pressure liquid chromatography, as well as
biotechnological and pharmaceutical liquid handing and assay
procedures, animal infusion and microfluidics and to deliver flow
to pulse sensitive de-factors and will be described in connection
with such procedures, although other utilities are
contemplated.
BACKGROUND OF THE PRESENT INVENTION
[0003] In small-scale chemical reactions, (e.g. for chemical and
biochemical laboratory research), the controlled addition of
reagents (liquids or gases) to a chemical reaction often is
accomplished by the use of disposable syringes. A researcher may
choose to fill a disposable plastic, glass or stainless steel
syringe with a desired reagent and then control the rate of
addition of the reagent into a reaction mixture, or into a
chromatography column, for example. Syringes are also employed for
the controlled introduction of a pharmaceutical or nutrient to a
laboratory animal or other biological system. Ideally introduction
of reagents or pharmaceuticals should be controlled accurately and
reproducibly over time.
[0004] While introduction of reagents or pharmaceuticals from a
syringe can be accomplished manually, the art has developed
automated, programmable syringe pumps for introducing reagents or
pharmaceuticals into a chemical reaction or biological system. With
the introduction of automated, programmable syringe pumps,
operators were freed of "hands-on" syringe operation, freeing the
laboratory worker to do other things, while at the same time
increasing accuracy and reproducibility of experiments.
[0005] A state of the art syringe pump 20 is illustrated in FIG. 1.
Referring to FIG. 1, syringe pump 20 employs a stepping motor or AC
motor (not shown) to turn a lead screw 22 and its mating nut or
half nut (not shown) to drive the plunger of a syringe 30. The lead
screw/stepping motor combination allows for a simple,
digitally-controlled open-loop plunger drive mechanism pusher block
26, and has a resolution defined by the number of steps and/or
microsteps per revolution of the stepping motor, pulley or gear
ratio, and the pitch of the lead screw. The pusher block carriage
assembly 26 rides on one or a plurality of guide rails 28. In a
conventional syringe pump, such as illustrated in FIG. 1, the axis
of the lead screw 22 which connects to the pusher block 26, is
offset from the axis of the syringe plunger 30. Such offset may
cause slight and undesirable non-linear motion or mechanical
linkages that connect the syringe plunger 30 to the lead screw 22,
which results in pulsatile deliveries. Conventional syringe pumps
also have substantial hysteresis, which limits their accuracy and
reproducibility.
[0006] Additionally, current state of the art syringe pumps require
significant set-up time, e.g., to accommodate different size
syringes and/or to change syringes, and also leave much to be
desired in terms of ease of use.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to overcome the
aforesaid and other disadvantages of currently available, manual or
automated programmable syringe pumps. In order to achieve this
objective, a detailed study was undertaken of both mechanical and
programmable control features of current syringe pumps. And, as a
result, several improvements were made in both mechanical and
programmable control features as will be discussed below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Further features and advantages of the present invention
will be seen from the following detailed description, taken in
conjunction with the accompanying drawings, wherein like numerals
depict like parts, and wherein:
[0009] FIG. 1 is a perspective view of a prior art syringe
pump;
[0010] FIG. 2 is a perspective view of an improved syringe pump
made in accordance with the present invention;
[0011] FIGS. 3-4 are perspective views from various angles showing
details of quick-connect/disconnect pusher block assemblies in
accordance with the present invention;
[0012] FIGS. 5 and 6 are perspective views showing details of
quiek-connect/disconnect syringe barrel flange capture assemblies
in accordance with the present invention;
[0013] FIG. 7 is a perspective view showing details of an
adjustable holder and clamp assembly in accordance with the present
invention;
[0014] FIG. 8 is a block diagram showing improvements in a
programmable syringe pump system in accordance with the present
invention;
[0015] FIG. 9 is a block flow diagram and 10 is a graphical
representation of improved flow rate control in accordance with the
present invention; and
[0016] FIG. 11 is a block diagram of a pumping control system in
accordance with the present invention.
MECHANICAL IMPROVEMENTS
[0017] As noted supra, current syringe pumps suffer from
undesirable non-linear motions of the mechanical linkage resulting
in pulsatile deliveries. Referring again to FIG. 1, pump pulsative
delivery is due, in part, to a torque on the pusher block assembly
26 as the lead screw 22 is advanced. The torque on the pusher block
assembly 26 twists the pusher block assembly 26 on the guide rail
28. While lengthening the bearing support 32 of the assembly 26
would reduce the aforesaid torque problem, simply lengthening the
bearing support 32 would reduce the length of the travel path
resulting in incomplete emptying of the syringes carried thereon.
And, while the guide rails 28 could be extended to accommodate
longer bearing supports 32, that would require increasing the size
and thus the footprint of the apparatus. Since the apparatus is
designed for laboratory use, increasing the footprint of the
apparatus is disadvantageous since laboratory bench and hood space
is a premium.
[0018] Referring to FIG. 2, in order to improve mechanical
performance without increasing the footprint of the apparatus or
contributing to pulsatility, the ends of the linear slide bearings
40 are lengthened at 42, 44 to extend beyond the forward and/or
trailing sides of the pusher block 46. Extending the ends 42, 44 of
the slide bearings 40 increases the length of the bearings which in
turn increases resistance to non-linear motion of the mechanical
linkage. In order to accommodate the increased length of the slide
bearings, without increasing the overall size of the apparatus, the
guide rail 28 support blocks 48, 50 are provided with recesses 52,
54 for accommodating the extended ends 42, 44 of the slide
bearings. Extending the length of pusher block 46 increases the
length of the bearings which in turn increases resistance to
undesirable non-linear motions. With this arrangement, the linear
guide or guide rails 28 are still supported and constrained by the
end support blocks 48, 50. However, the pusher block 46 still is
permitted to travel the entire working length of the lead screw 22,
since at the fullest extent of travel, the extended bearing ends
42, 44 slide into the recesses 52, 54 in the support blocks 48, 50.
The resulting structure is a substantially lengthened slide bearing
which provides a significantly improved mechanical linkage far less
susceptible to pulsatility, but without increasing the size of the
syringe pump or its footprint.
[0019] Referring also to FIGS. 3-6, another aspect of the invention
provides a quick connect/disconnect which facilitates loading and
unloading of syringes from a pump, eliminates the need for special
tools to load and unload syringes from the pump, and eliminates the
need for special tools to adjust for different size syringes. More
particularly, as shown in FIGS. 3 and 4, the pusher block 46
includes a quick connect/disconnect flange capture bracket 108 for
capturing the plunger flange when a syringe plunger 103 (shown in
phantom in FIG. 3) is loaded on the pump. The plunger flange
capture bracket 108 which is provided with tabs 107 which in turn
are slidably mounted on a threaded shaft 110 that runs through
pusher block 46. The distal end of the shaft 110 opposite the
thumb-screw or knob 109 includes a flange and retaining clip or
other similar device so that as the thumb-screw or knob 109 is
turned, the side tabs 107 of the flange capture bracket 108 are
pulled tightly against the pusher block 46, locking the assembly in
place. The shaft 110 may be provided with an anti-rotation device
to eliminate rotation of the shaft 110 as the thumb-screw or knob
109 is turned, thus further facilitating the quick
connect/disconnect tool-free locking procedure. A thumb-screw or
knob 109 permits a user to lock and unlock the shaft providing an
adjustable gap 105 between the plunger flange capture bracket 108
and the syringe pusher block 46. Alternatively, knob 109 could be
replaced by a rocker cam. The adjustable gap 105 may be set to fit
a variety of syringe plunger flanges associated with different
types and sizes of syringes available for use with the syringe
pump. To capture a syringe plunger flange, the syringe plunger
flange capture bracket 108 is first opened to permit a syringe
plunger flange to be loaded on the pump. The bracket 108 is then
pushed firmly against the syringe plunger flange, to close any gap
between the syringe pusher block 46, the syringe plunger flange and
the syringe plunger flange capture bracket 108. The syringe plunger
flange capture bracket 108 is then locked by twisting thumb-screw
or knob 109.
[0020] Syringe pusher block 46 is slidably adjusted along the lead
screw 22 by squeezing release handles 111, 113 which unlock when
squeezed. Release handles 111, 113 are conventional in syringe
pumps and will not be further described.
[0021] Referring now to FIGS. 5-6, the syringe pump also includes a
quick connect/disconnect syringe barrel and syringe barrel flange
capture assembly. The syringe barrel flange capture assembly will
first be described. The barrel flange capture assembly includes a
barrel flange capture bracket 128 which is provided with tabs 170
which in turn are slidably mounted in a locking shaft 110.
[0022] Locking shaft 110 is provided with a locking nut 164 and a
threaded thumb screw or knob 109. The shaft 110 passes through tabs
170 on the syringe barrel flange capture bracket 128 and then
through syringe block 106. The distal end 174 of the shaft 110
opposite the thumb-screw or knob 109 includes a flange 176 and
retaining clip 178 or other similar device so that as the
thumb-screw or knob 109 is turned, the side tabs 170 of the flange
capture bracket 128 are pulled tightly against the syringe block
106, locking the assembly in place. Alternatively, knob 109 may be
replaced by a rocker cam. The shaft 110 may be provided with an
anti-rotation 182 devices to eliminate rotation of the shaft 110 as
the thumb-screw or knob 109 is turned, thus further facilitating
the quick connect/disconnect tool-free locking procedure. While the
syringe barrel flange capture bracket 128 is unlocked, it may be
slidably adjusted with respect to the syringe block 106, providing
an adjustable gap 112. The adjustable gap 112 may be set to fit a
variety of syringe barrel flanges 104 associated with different
types and sizes of syringes available for use with the syringe
pump.
[0023] Referring now to FIG. 7, and yet another mechanical
improvement, there is provided a bar and clamp for mounting to a
syringe pump for facilitating accommodation of syringes of
different sizes, and/or for permitting simultaneous infusion and
withdrawal of liquids from a pair or more of syringes whose
plungers are mounted fixedly on opposing faces of a moveable
carriage. More particularly, as shown in FIG. 7, a syringe holder
and clamp assembly 230 is mounted on one end of an adjustable
extension bar 202 that is attached to the main block 234 with a
mechanical fastener 236 such as a twist nut or cam-lock. The main
block 234 is rigidly attached to the syringe pump, i.e. and
replaces block 50 as shown in FIG. 2. The syringe holder and clamp
assembly 230 may be mounted with the extension bar 202 extending to
either side and is slidably adjustable with respect to the main
block 234 to accommodate a variety of syringes and syringe sizes
that may be used in conjunction with a syringe pump whose overall
length is fixed by design. In this manner, essentially any size
syringe and/or combinations of syringes of different sizes may be
used in a pumping configuration. Also, a pair or more of syringes
may be fixedly mounted on a single syringe pump permitting
simultaneous infusion and withdrawal of liquids.
[0024] Summarizing to this point, the present invention provides
several mechanical improvements in syringe pumps. These include, in
no particular order of importance:
[0025] In one aspect of the invention there is provided a syringe
pump in which a pusher block is slidably mounted on bearings on one
or more guide rails, wherein the pusher block is advanced or
retracted by a lead screw having an axis which is offset from the
axis of the one or more guide rails which are supported at their
respective ends by support blocks. Improved resistance to torque is
achieved by extending the forward and/or trailing sides of the
bearings, wherein the guide rails support blocks include recesses
for accommodating the extended ends of the carriage slide
bearings.
[0026] The invention also provides a syringe pump having a
tool-free quick connect/disconnect facilitates loading and
unloading of syringes from the pump. In one embodiment, the quick
connect/disconnect comprises a slidably adjustable syringe plunger
flange capture bracket, and preferably includes a locking cam and
nut, and/or a threadable knob for drawing side tabs of the flange
capture bracket against the pusher block. In another embodiment,
the quick connect/disconnect comprises a slidably adjustable
syringe barrel flange capture bracket, and preferably includes a
locking cam and nut, and/or a threadable knob for drawing side tabs
of the flange capture bracket against the syringe block.
[0027] Yet another aspect of the invention provides a syringe pump
in which a pusher block is slidably mounted on one or a plurality
of guide rails, and further including a tool-free quick
connect/disconnect syringe barrel clamp.
[0028] The present invention also provides a syringe pump in which
a pusher block is a carriage which is slidably mounted on one or a
plurality of guide rails; and including a syringe holder and clamp
mounted on an extension bar, wherein the syringe holder and clamp
is slidably adjustable with respect to the pusher block to
accommodate a variety of syringes and syringe sizes.
[0029] It is thus seen that the present invention provides several
mechanical enhancements by the improved performance and
reliability, convenience and flexibility over current syringe
pumps.
[0030] Yet other improvements over current syringe pumps will be
described below.
Programmable Control Improvements
[0031] Referring to FIG. 8, in yet another aspect of the invention,
there is provided a master-satellite syringe pumping system 300
which comprises one or more satellite syringe pumps 302 controlled
and powered by a separate stand-alone master pump 304. The master
pump 304 includes a control system 306 having microprocessor for
storing run protocols, and including a graphical user interface
(GUI) 308 for permitting user input and for displaying user
information, and a power supply 310 which provides, as needed,
electrical power for the operation of one or more satellite syringe
pumps 302. Cables 312 containing a plurality of conductors are used
to distribute electrical power and control signals, as needed, and
as a pathway for communication between the master pump 304 and each
of the satellite units 302. With this arrangement, a user may
adjust and set any or all master/satellite pump operation
parameters from the master pump 304 control 306, without the need
for a PC or other stand-alone control system.
[0032] Referring now to FIGS. 9 and 10, yet another improvement,
provides better flow rate control when delivering fluid from
multiple syringes into a single flow channel. The present invention
provides a way of operating a pair (or more) of syringe pumps in a
coordinated and sequential order, and combining their output into a
single flow channel. More particularly syringes 400, 402 are
connected via tubing 406, 408 and valving 407, 409 into a single
main distribution tube 410. Flow from each syringe is adjusted to
contribute to a total flow rate desired in the main distribution
tube 410. The overall process is as follows: fluid from the first
syringe 400 is set at a desired flow rate. At a predetermined time
before the volume of fluid contained in the first syringe 400 is
depleted, the flow rate from the first syringe 400 is reduced,
while the flow rate from a second syringe 402 is increased to match
the reduction in flow rate from the first syringe 400. Flow volumes
from the first and second syringes 400, 402 are adjusted until the
flow rate from the first syringe 400 is at zero, while the flow
rate from the second syringes 402 is adjusted to the desired flow
rate. The first syringe 400 may then be replaced with a fresh
filled syringe, or the first syringe may be refilled and the cycle
repeated. In this manner, perturbations of flow are minimized at
the cross-over between syringes. This method may be used to either
infuse or withdraw fluids through the main distribution tube 410,
resulting in a smooth flow rate. This improvement is particularly
useful in connection with liquid chromatography where multiple
pumps may be employed, and continuously smooth flow is desired.
This method of crossover correction may be used with 2, 3, 4 etc.
pumps with combined flow.
[0033] Yet other embodiments are possible. For example, pump flows
may be controlled to vary, for example, by pulsing so as to mimic
physiological characteristics such as blood flow, or to mimic a
physiological waveform such as, for example, an EKG through a
dispense profile. This latter feature is particularly useful where
syringe pumps are being used to administer a physiological fluid,
for example, to a laboratory animal. This also may use 1, 2, 3, 4
or more syringe pumps.
[0034] In yet another aspect of the invention, illustrated in FIG.
11, pumping protocols are stored in an electronic library 450, and
the syringe pump controlled by an electronic control system 452 to
run at a pre-programmed speed, or other variable. Other variables
stored in the library include, for example, any and all parameters
associated with the operation of the pump and experiment: syringe
capacity, pressure, force of syringe, syringe diameter, syringe
strength, syringe length, temperature, date, time, operator,
approval levels to operate, languages, etc. In a preferred
embodiment, electronic control system 452 contains a processor
operably coupled to a memory 454, a motor driver circuit 456 and a
graphical display system 458 whose user interface imagery is
controlled by the processor via software and firmware stored in
memory. Actuation force may be controlled by the pt mp operator
using one of two methods. In one method, the pump operator, through
the graphical display system or a PC controlled software terminal,
may select a force rating equivalent to a percentage of the maximum
possible actuation force of the syringe pump. In another method,
the pump operator may select a syringe, which calls for a default
force rating which has been pre-stored in a software library and
which corresponds to a specific syringe. The library may contain an
array of characteristics for a given syringe, including volumetric
capacity, internal diameter and maximum safe applied force. Maximum
safe applied force is an operational control limit of applied force
above which level may result in damage to the syringe. In either
method, the electronic control system is tasked with regulation of
electrical current to the stepper motor or other motor.
Consequently, torque generated by the stepper motor may be
controlled, and thus force applied to the syringe plunger as the
motor torque is translated into a linearly-directed force through
the leadscrew and half-nut or full-nut or rack and pinion. The
half-nut or full-nut or rack and pinion is connected in a rigid
manner to the linear slide mechanism, so all forces applied upon
the half-nut or full-nut are transferred directly to the linear
slide mechanism and finally to the syringe plunger. In a preferred
embodiment the system also may include a bar code reader a RFID
reader, IR reader, or other reader 460 for identifying the
particular syringe 462 as the syringe is placed in the pump 464.
The output from the reader is then transmitted to the processor
identified by the electronic library 450, and the control set.
[0035] Volume of the syringe can be recorded in this table and can
be read by an ultrasonic signal directed down the syringe and
measured by reflections back to a sensor which will read actual
volume in the syringe. The volume measurements may be stored in the
library, and updated as volume varies in the pump/experiment.
[0036] Also, if desired, the syringe pump may be provided with
sensors and programs to adjust for temperature, pressure feedback
sensors, and the like. Additionally, the syringe pump may be
controlled by a processor which includes a memory having a library
of selectable user interfaces, etc which permits an operator to
input variables (material, syringe size, etc.) and then choose from
a library of pre-assigned test protocols or the like.
[0037] Summarizing, the present invention also provides several
programming and control improvements for operating syringe pumps.
These include, in no particular order of importance:
[0038] In one aspect of the invention, there is provided a syringe
pump control system comprising a master pump and one or more
satellite syringe pumps, in which the satellite syringe pumps are
controlled and powered by the master pump, and in which the control
system electrical power and controls for operation of the one or
more satellite pumps are distributed from the master pump.
Preferably, the master pump includes a control system having a
memory for storing and controlling run protocols.
[0039] The invention also provides a method for maintaining smooth
and consistent flow rates in a single flow channel, when the total
flow rate is comprised of the sum of flows eminating from at least
two syringes operated in a coordinated and sequential order. With
such method it is possible to remove and replace or refill one of
syringe while the other or others are dispensing or withdrawing
fluid at a predetermined flow rate.
[0040] In another aspect of the invention, one or more syringe
pumps are pulsed to mimic physiologic characteristics, e.g., an
EKG, or blood flow.
[0041] The present invention also includes a microprocessor
controlled syringe pump system in which syringe actuation forces
are controlled through look-up table in a computer library, which
in a preferred embodiment includes pre-assigned test protocols.
[0042] In yet another aspect of the invention the syringes carry
bar codes or RFID tags, or IR tags, and the pump includes a bar
code reader, RFID reader or IR reader for identifying a syringe and
transmitting information regarding the syringe to the
microprocessor.
[0043] In yet another aspect an encoder will mark rotational
position of the lead screw, while another encoder will read the
travel of the pusher block at a set rate. The theoretical time and
distance will be calculated and compared to actual. These values
will be stored in a library. During a run the theoretically stored
values will be compared to actual and fed into a motor control
circuit to increase or decrease block movement and screw turning to
more closely achieve theoretical time and distance. This will
result in a smooth flow with minimal pulsings and high accuracy and
precision. The encoder will insure accurate mapping irrespective of
where the block starts.
[0044] The above invention has been described in connection with
syringe pumps. However, several of the above described features may
have utility outside of the syringe pump field. For example, the
flow rate control shown in FIGS. 9 and 10 may be used in other flow
control applications.
[0045] Yet other features and advantages of the invention will be
apparent to one skilled in the art, taking into account the above
description.
* * * * *