U.S. patent number 3,730,650 [Application Number 05/071,773] was granted by the patent office on 1973-05-01 for peristaltic pump and system therefor.
This patent grant is currently assigned to Technicon Instruments Corporation. Invention is credited to Nelson G. Kling, deceased.
United States Patent |
3,730,650 |
Kling, deceased |
May 1, 1973 |
PERISTALTIC PUMP AND SYSTEM THEREFOR
Abstract
A peristaltic pump is provided, which may have auxiliary fluid
introduction, for a plurality of resilient pump tubes progressively
occluded concurrently along a portion of their lengths,
recurringly, to advance fluids therethrough by a pressure roller
assembly; and a control system for the pump to render the roller
assembly inoperative to advance fluids. A platen is mounted for
movement from an operative position, in which the pump tubes are
engaged and sandwiched between the platen and the roller assembly,
to an inoperative position in a direction away from the roller
assembly. In the inoperative position of the platen, a tube or
tubes of the auxiliary fluid introduction, which includes a
pressure pin cooperating with a pad engageable with the tube or
tubes therebetween, are released. The platen is power-operated to
move to at least one of the two aforementioned positions
thereof.
Inventors: |
Kling, deceased; Nelson G.
(late of Ocala, FL) |
Assignee: |
Technicon Instruments
Corporation (Tarrytown, NY)
|
Family
ID: |
22103492 |
Appl.
No.: |
05/071,773 |
Filed: |
September 14, 1970 |
Current U.S.
Class: |
417/475;
417/477.14; 417/477.11 |
Current CPC
Class: |
F04B
43/1223 (20130101); G01N 35/08 (20130101) |
Current International
Class: |
G01N
35/08 (20060101); F04B 43/12 (20060101); F04b
043/08 (); F04b 043/12 (); F04b 045/06 () |
Field of
Search: |
;417/474,475,476,477,223
;92/13.2,100,98R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Croyle; Carlton R.
Assistant Examiner: Gluck; Richard E.
Claims
WHAT IS CLAIMED IS:
1. A fluid analysis system for transport of a sample comprising a
support, a plurality of fluid-conveying pump tubes on the support,
a platen assembly to back the pump tubes, a pressure assembly
having means operable to engage concurrently and progressively
occlude said tubes against said platen along their lengths, and to
release said tubes, at least one of said tubes being connected to a
source of sample for transport of the latter, one of said
assemblies being movably mounted on said support to shift to occupy
an operative position in which said tubes are compressed and to
occupy an inoperative position in which said tubes are released
from pressure thereon by the last-mentioned assembly, and
power-operated means to move said one of the assemblies to each of
said positions, a pressure source, a conduit connecting the
pressure source to said power operated means, a vent valve located
in the conduit, said vent valve responsive to a malfunction of said
system to vent the power-operated means and thereby shift the
movable assembly to said inoperative position rendering the system
inoperative.
2. A system as defined in claim 1, wherein: said movable assembly
is removably mounted on said support for access to the pump
tubes.
3. A system as defined in claim 1, wherein: said movable assembly
is mounted so as to be swingable on an axis for access to the pump
tubes.
4. A system as defined in claim 1, wherein: said movable assembly
is the platen.
5. A system as defined in claim 1, wherein said movable assembly is
the platen and said means to shift the platen to said positions
thereof comprises a piston operated by fluid pressure.
6. In an analysis system for transporting a sample, a peristaltic
pump comprising a support; a plurality of pump tubes on the
support; a platen assembly to back the pump tubes; a pressure
assembly having means operable to engage concurrently and
progressively occlude said tubes against said platen along their
length, and to release said tubes; one of said assemblies being
movably mounted on said support to shift rectilinearly to occupy an
operative position in which said tubes are compressed and occupy an
inoperative position in which said tubes are released from pressure
thereon by the last-mentioned assembly; fluid-operated means to
move the last-mentioned assembly to one of said positions; a fluid
pressure source; conduit-forming means between said pressure source
and said fluid-operated means; the pressure source being connected
to a source of reagent to pressurize the last-mentioned source for
transport of the reagent for mixture with the sample; and valve
means to vent said fluid-operated means.
7. An analysis system as defined in claim 6: further comprising a
timing signal device having an operative connection to said valve
means to operate the latter to vent said fluid-operated means.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to fluid pumps, and particularly to
peristaltic type proportioning pumps utilizing compressible tubes,
which are advantageously utilized in flowing stream analytical
systems.
2. Description of the Prior Art
In systems of this kind, a flowing stream of sample liquid, which
stream may be a continuous monitoring stream, or a stream of
sequential liquid samples, may be continuously mixed in a
predetermined proportion with one or more reagents, and may be
otherwise processed to provide, say, a color reaction, the optical
density of which at a particular wave length is responsive to the
concentration of a constituent of interest in the sample. Such a
system is illustrated and described in U.S. Pat. No. 2,797,149
issued June 25, 1957.
A peristaltic pump suitable for use in such a system is illustrated
and described in U.S. Pat. No. 3,425,357 issued Feb. 4, 1969,
having auxiliary fluid introduction for the purpose of maintaining
constant the proportions of reagents and samples, which
proportioning problem was earlier recognized and described in U.S.
Pat. No. 3,306,229 issued Feb. 28, 1967.
In addition to the roller assembly coacting with pump tubes, the
pump of U.S. Pat. No. 3,425,357, supra, included in the auxiliary
fluid introduction, a pressure pin and pad for periodically
occluding therebetween at least one fluid tube, and a mechanism to
release the tube periodically for flow therethrough, once between
the separation of successive rollers from the roller tubes.
According to the last-mentioned patent, a linkage was provided
coupling the platen to the aforementioned pad so that release of
the platen from the roller tubes effected release of the tube or
tubes from the pressure pin and pad.
That patent illustrates and describes, among other features of the
pump, a pressure roller assembly, with a coacting platen assembly,
which is inverted with reference to the corresponding assembly of
U.S. Pat. No. 3,306,229, supra, and that illustrated and described
in an earlier U. S. Pat. No. 2,935,028 granted May 3, 1960.
The pressure roller assembly of U.S. Pat. No. 3,425,357, supra,
coacts with a platen assembly located above it, which platen
assembly is swingable manually on an axis, in a manner similar to
the aforementioned earlier pressure roller assemblies, to clear the
pump tubes and relieve stress thereon when the pump will not be in
use for a period of time, thereby lengthening the service life of
the pump tubes. This not only requires the person operating the
system to remember to relieve pressure on the pump tubes when the
pump is not in use, but also to make the effort to disengage
manually the platen from the tubes. This procedure could be
forgotten, with resultant tube failure, and was a nuisance. The
present invention obviates the necessity of manipulation of either
the pressure roller assembly or the platen assembly to relieve
stress on the pump tubes.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved
peristaltic pump of the type having auxiliary fluid introduction as
aforesaid including a mechanism for occluding a fluid tube and
timing the release of fluid therefrom, for constant uniform
proportioning of the fluids advanced by the pump, wherein provision
is made for the release from compression of all the tubes including
the release of compression of the fluid-supply tube of the
aforementioned auxiliary mechanism, when the pump is not in use,
thereby precluding the development of a permanent set in any of
these tubes.
Another object is to provide in such a pump, a platen mounted to
occupy an operative position and an inoperative position, and power
operated means to move the platen to one of these positions. There
is also provided in such a pump a platen which is self-moving to
the other position.
Still another object is to provide such a pump in a system wherein
the system has a fail-safe feature operative to release the pump
platen from the pump tubes.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawing
FIG. 1 is a top plane view of a peristaltic proportioning pump
embodying the invention;
FIG. 2 is a sectional view taken on line 2--2 of FIG. 1;
FIG. 3 is a sectional view taken on line 3--3 of FIG. 1;
FIG. 4 is an elevational view looking in the direction of the
arrows 4--4 of FIG. 1;
FIG. 5 is a diagramatic view of a system in which the pump of the
invention may be a part.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As indicated particularly in FIG. 1 of the drawings, the pump of
the invention is of the type illustrated and described in U.S. Pat.
No. 3,425,357, supra, the disclosure of which is hereby
incorporated by reference. The pump of the last-mentioned patent is
an improvement of the pump of U.S. Pat. No. 3,306,229, supra, the
disclosure of which is also hereby incorporated by reference.
Briefly, the pump includes an outer box-like housing 10 (FIG. 1)
wherein a pressure device (FIG. 2), indicated generally at 12, is
supported which includes two spaced-apart sprocket chains, one
being indicated at 14, such as described in U.S. Pat. No.
3,425,357, which are associated with spaced-apart respective guide
plates, one being indicated at 18. The sprocket chains are driven
in the manner illustrated and described in the last-mentioned
patent. A plurality of rollers 16 are journaled by and between the
two sprocket chains and these rollers engage and pass over the
aforementioned guide plates.
A cover assembly, indicated generally at 20 has two side walls 22
each of which has on an extension thereof a hook portion 24 adapted
to fit under and pivot about a respective horizontal stud 26 fixed
to the housing. The cover assembly 20 includes a platen assembly,
indicated generally at 28, and best shown in FIGS. 2, 3 and 4. The
platen assembly 28, supported by the cover assembly 20, extends
into an aperture 30 formed in the top of the housing 10. A pair of
grooved, spaced apart, pump-tube-locating blocks 32 are releasably
mounted in a conventional manner on the top of the housing adjacent
the aperture 30 therein at opposite sides thereof. A plurality of
pump tubes 34, 34a, may be disposed between the two blocks 32 over
the aperture 30 in side by side relation as shown in FIG. 1.
Collars 36 fixed to the respective pump tubes in pairs abut the
respective blocks 32 to support the tubes as shown in the
last-mentioned view.
When the cover assembly 20 carrying the platen assembly 28 is swung
down to the position shown in FIG. 2 and latched in place by latch
assemblies, indicated generally at 38, in the manner disclosed in
the last-mentioned patent, the pump tubes may be pressed downwardly
subsequently, in a manner to be described hereinafter, by the lower
face of the lower part of the platen assembly 28 against those
rollers 16 which are riding on the upper edges of the guide plates
18, so that the tubes are occluded by these rollers as indicated in
FIG. 2. When these rollers are advanced by the sprocket chains they
progressively occlude these tubes along their respective adjacent
lengths, advancing such fluids as are contained therein. It will be
noted that at least two rollers are always in occluding engagement
with the tubes. The pump tubes 34 and 34a are customarily made of a
compressible resilient material such as polyvinyl chloride sold
under the trademark "Tigon."
It will be appreciated that while a peristaltic type pump utilizing
a plurality of rollers has been illustrated, any tube occluding
means which is regularly periodically operated, such as a cam, or a
series of fingers, may be utilized in the pressure assembly.
The cover assembly 20, together with the platen assembly 28, is
completely removable from the pump housing for complete access to
the pump tubes. To mount the cover assembly with the platen to the
housing 10, the aforementioned hooks 24 of the side walls are
engaged under the studs 26 and the cover and platen assemblies are
swung as a unit downwardly, on an axis to the position shown in
FIG. 2, to be latched as aforesaid by the aforementioned latch
assemblies 38 shown in FIG. 1. It will be understood from the
foregoing that the cover assembly with the platen assembly 28,
after being unlatched, may be swung upwardly on the last-mentioned
pivotal axis from the positions of FIGS. 1 and 2 without the
removal thereof from the pump.
Referring again to FIG. 1, one of the pump tubes 34 may convey
sample while the other illustrated pump tube 34 may convey a
reagent. Pat. No. 3,306,229, supra, describes to some extent, as
does Pat. No. 3,425,357, supra, the desirability of controlling the
input of a segmenting fluid, which may be gas, into the sample tube
or the reagent tube downstream from the pump in a conventional
junction, not shown. In the present illustration, this segmenting
fluid may be conveyed by the pump tube 34a which is shown in a
position to be acted upon by the pump to convey fluid therethrough.
However, as indicated in U.S. Pat. No. 3,306,229, supra, this fluid
admitting tube need not have the fluid conveyed therein by the pump
but may be supplied from an external source, such as a container of
pressurized gas for example.
Specifically the pump tube 34a for advancing the segmenting fluid
is pinched closed, except when the fluid therein is to be released.
It is also desirable that this pinching be released when the
pumping operation is discontinued to avoid a permanent set in the
tube, as indicated in U.S. Pat. No. 3,425,357, supra.
A fluid tube block assembly, indicated generally at 39, is disposed
on the top of the housing 10. This assembly includes a U-shaped
block support 40 having two spaced-apart upstanding legs 42 and
conventionally fixed to the top of the housing. A shaft 44 is
journaled between and through these legs 42. A fluid tube support
plate 46 is pivotly journaled on the shaft 44. This plate includes
ears 48 by which the plate is journaled on the shaft 44, and
further includes a plate portion 50 having two spaced-apart
pluralities of upstanding spaced-apart teeth, as shown in FIG. 1,
which provide tube receiving grooves therebetween. A tube 34a can
be seen to be located in appropriate ones of these grooves. A
resilient pad 52 is adhered to the top of the plate between the two
series of teeth. Rearwardly, the plate 46 has an inverted L-shaped
portion 54.
A pressure pin 56 is fixed to the shaft 44 by two spaced-apart arms
58. The distal ends of these arms 58 are fixed to the shaft 44. The
pressure pin 56 is operated by the shaft 44, which has a rocking
movement, through an operative connection to the rollers 16 of the
pressure device in a manner which forms no part of the present
invention and is fully described in U.S. Pat. No. 3,425,357, supra.
The pressure pin 56 presses the pump tube 34a against the pad 52 to
occlude the tube except at intervals dictated by the movement of
the tube rollers when the pump is in operation. The pressure pin
element 56 coacting with the pad element 52 to occlude periodically
the tube 34a conveying the segmenting fluid forms the
aforementioned auxiliary fluid introduction part of the pump
mechanism.
With reference to the cover assembly 20, supporting the platen
assembly 28 constructed for power operation, the construction and
arrangement of which parts of these assemblies are closely related,
it may be noted first that the platen assembly 28, in the
illustrated form of the invention, is moved to the operative
position thereof by power, after the cover assembly is latched in
position as aforesaid by the latch mechanisms 38. This subassembly
of the pump includes a relatively thick metal plate 60 secured to
the aforementioned side walls 22 as by suitable fasteners, not
shown, which walls depend from the plate 60, one of which is shown
in FIG. 3 in this relationship. The plate 60 has a central opening
defined by a cylinder wall 62 as shown in FIG. 2. The plate 60 is
horizontally arranged and the cylinder wall is upwardly arranged,
having an open lower end as shown in the last mentioned view.
Closing the upper end of the cylinder is a cover plate 64 which
sandwiches a diaphragm 66, which may be structured of rubberized
fabric, between itself and the upper end of the cylinder 62 by
being interposed between a flange of the cover plate 64 and the
upper surface of the plate 60. The cover plate 64, the diaphragm 66
and the plate 60 are secured together in the area of the
last-mentioned flange by suitable fasteners not shown.
As shown in FIG. 2 the cover plate 64 has the shape of an inverted
dish and is round in outline as seen in FIG. 1.
A relatively thick metal plate of circular outline forms a piston
68 received in the cylinder 62 with clearance as shown in FIG. 2.
The diaphragm 66 has a central opening the marginal portion of
which extends over the piston 68 and is secured thereto by an
overlying plate 70. A relative thick metal plate 72 abuts the
bottom of the piston 68 in flatwise relation and forms at least a
part of the platen assembly 28. The lower face of the plate 72,
indicated in FIG. 2 to be in engagement with the pump roller tubes,
has rounded marginal portions as shown, and if desired, this face
of the plate 72 may be covered with a sheet of suitable cushioning
material not shown. Fasteners 74 extend through the plate 70, the
diaphragm 66, the piston 68 and into the platen 72 to secure these
elements together, one being shown in FIG. 2. The platen 72 may be
oblong with its longest dimension arranged transversely as the pump
tubes 34, 34a.
As shown in FIG. 2 the piston 68 has a central opening 76 extending
axially therethrough and in alignment with the cavity 78 directed
upwardly in the platen 72. A sealing ring 79 may be interposed
between the piston 68 and the platen 72 in an enlargement of the
bore 76.
A vertical stub shaft 80 has a reduced end portion thereof
extending upwardly through the center of the cover plate 64 and
secured to the top of the plate 64 as by having a nut 82 threaded
thereon. The portion of the shaft of larger diameter abuts the
underside of the plate 64 in the manner shown in FIG. 2, so that
the shaft depends from and is fixed to the cover plate 64. The
last-mentioned shaft 80 has at the lower end thereof a radial
flange 84. The shaft 80 extends through a bushing 86 which has a
radial flange 88 abuting the underside of the plate 70. A helical
spring 90 surrounding the bushing is compressed between the
aforementioned flange 88 of the bushing and the aforementioned
radial flange 84 of the shaft, which spring has the action of
urging the piston 68 and the platen 72 in an upward direction to
the position shown in phantom in FIG. 2 in which the platen 72 is
in the inoperative position thereof. In the last-mentioned position
the upper surface of the plate 72 providing the platen abuts the
underside of plate 60 which acts as a stop to limit upward travel
of the platen 72.
To prevent angular movement of the piston 68 with its associated
parts in the cylinder provided by the plate 60, guide pins are
vertically arranged and fixed to the cover 64 in a manner to depend
therefrom to coact with guide openings in the plate 68, one such
guide pin 92 being shown in FIG. 2 cooperating with one such guide
opening 94. Also as shown in the last-mentioned view, the cover
plate 64 has a fluid inlet tube 96 extending therethrough for
admission of fluid above the piston 68 and the diaphragm 66. It
will be understood from the foregoing that fluid admitted to the
tube 96 serves to force the piston 68, through movement of the
diaphragm 66, in a downward direction carrying with it the platen
72, for engagement of the platen assembly with the roller pump
tubes in the manner shown in FIG. 2. Fluid may be vented through
the tube 96, on which occasion the spring 90 serves to return the
piston 68 and the platen 72 to the upper positions thereof in which
the pump tubes are cleared by the platen assembly 28 so as to
re-expand. It will be readily apparent that when the platen
assembly 28 is in the raised position thereof, movement of the tube
rollers with the sprocket chains is ineffective to convey fluids
through these tubes. The travel of the platen assembly 28 to the
inoperative position may be approximated 0.50 inch. A simple
conventional limit switch, not shown, may be operated on upward
movement up the platen assembly 28 to its inoperative position
thereof to discontinue the driving connection to the sprocket
chains 14 carrying the tube rollers 16, and thereby shut down the
pump.
The operative connection between the piston 68 or the platen 72 to
the fluid tube block assembly 39, which serves to release pinching
pressure on the fluid tube 34a, when the platen assembly 28 is in
the inoperative position thereof, will now be described. This
operative connection includes a lever 98, best shown in FIG. 4, one
end of which is forked, as at 100, to receive the end of a pin 102
extending horizontally and fixed in the platen plate 72 in a
conventional manner. The forked end 100 of the lever receiving the
pin 102 is shown to advantage in FIG. 3.
Intermediate of its ends the lever 98 is pivoted, as at 104, to one
of the walls 22 fixed to the cylinder 60. The other end of the
lever 98 (FIGS. 1 and 4) has a laterally directed finger 106
underlying the inverted L-shaped portion 54 of the plate 46 pivoted
to swing on the shaft 44 as previously described. When the lever 98
is in the full line position of FIG. 4 the plate 46 is maintained
in a position to coact with the pressure pin 56 so that the latter
may periodically occlude the pump tube 34a in the manner previously
discussed. However, when the platen assembly 28 is raised to the
inoperative position thereof the lever 98 is swung on the axis of
its pivot 104 from the full line position of FIG. 4 to the position
shown in phantom in which the plate portion 54 may swing
downwardly, following the lowering, swinging movement of the finger
106 of the lever, thereby releasing the tube 34a from the pressure
pad 56 carried by the plate 46, so that the tube 34a may
re-expand.
The previously described pump may be used in a system such as shown
in FIG. 5 which may be a part of an automated analytical system
such as that illustrated and described in U.S. Pat. No. 3,241,432
issued Mar. 22, 1966. There is indicated at 108 a pressure source
which may be either a pump or a pressurized container of fluid such
as a gas. For the purpose of example the pressure source 108 may be
considered as a pressurized container of gas having an outlet in
which is interposed a pressure regulator 110. Branching off this
outlet is a tube 112 to pressurize a container 114 which may be
filled with a fluid such as a liquid reagent. Connected to the
aforementioned outlet of the pressure source 108, as shown in FIG.
5, is a tube 116 connected to a valve 118, controlled by a timing
signal 120, which valve may be of the three-way type to
interconnect through the valve 118 the tube 116 and a tube 122 or
connect the tubes 116, 122 to the ambient atmosphere through a
vent. The tube 122 is connected to the inlet tube 96 previously
described in the pump. It will be evident from the foregoing that
fluid entering the tube 96 against the pressure of the pump spring
90 operates to move the platen assembly 28 of the pump to the
operative position thereof in which fluid may be conveyed by the
pump.
A sampler, indicated at 124, may be of the type illustrated as
described in U.S. Pat. No. 2,879,141, issued Mar. 24, 1959, in
which successive sample cups are presented to a station whereat an
aspirating tube aspirates that particular sample to direct it
through a tube such as the tube 126 showin in FIG. 5 of the present
drawings. Suction is provided in the tube 126 by the operation of
the pump in the aforementioned manner which pump, solely for
purposes of example, is shown as operatively connected only to the
tube 126. Other fluid lines may, of course, be added as
desired.
A tube 128 extends from the pressurized container 114 of reagent
or-the-like for the exit therefrom under pressure of the reagent
which is directed by the tube 128 to a flow control device 130 from
which it exits at a lower rate in a tube 132. The tube 132 is
branched to the pump outlet shown in FIG. 5 in which the reagent
joins the sample upstream of a mixer 134, which may be of the coil
type, in which the ingredients of the stream are well mixed
together. As indicated in the last-mentioned view the stream then
passes downstream from the mixer directly to analysis apparatus or
for further treatment prior to analysis, which analysis may take
the form of examination in a colorimeter or in a flame photometer.
The sample stream flowing into and from the pump may be segmented
by a fluid such as a gas, if desired, as by being provided with gas
segments through the operation of the pump, through the inlet of
gas through the tube 126 between samples or by other means. This
segmenting fluid tends to maintain sample integrity, as by
separating samples one from another, and also serves to cleanse the
tubing walls.
The timing signal 120, controlling the valve 118 and through it the
position of the pump platen assembly 28, may be controlled in a
variety of ways which will be apparent to one versed in the art.
Obviously, the timing signal may be controlled by a master switch,
not shown, operative to turn off the entire system including the
portion of the system shown in FIG. 5. The timing signal 120 may
also be controlled by a known device for detecting clogging in a
fluid line such as a sample line, as illustrated and described in
U.S. Patent 3,424,557 issued January 28, 1969, for example. It may
be operated by a leak detector of the conductivity type, which is
also known, associated with the pump. Still further, it might be
governed by a malfunction detector such as a pressure sensor or a
malfunction detector of the type sensing flow rates as illustrated
and described in U.S. Patent 3,529,635 issued September 22, 1970,
for example.
It is believed that many advantages of this invention will now be
apparent to those skilled in the art. The foregoing description is
illustrative, rather than limiting, as a number of variations and
modifications may be made without departing from the true spirit
and scope of the invention. The invention is limited only by the
scope of the following claims.
* * * * *