U.S. patent application number 10/887623 was filed with the patent office on 2006-01-12 for integrated pump and check valve apparatus.
Invention is credited to Garret Angove.
Application Number | 20060008365 10/887623 |
Document ID | / |
Family ID | 35541561 |
Filed Date | 2006-01-12 |
United States Patent
Application |
20060008365 |
Kind Code |
A1 |
Angove; Garret |
January 12, 2006 |
Integrated pump and check valve apparatus
Abstract
A pump apparatus is provided which comprises a displacement pump
and a check valve apparatus. The displacement pump comprises a
reciprocating piston within a housing having an interior wall
spaced apart from the piston. The check valve apparatus comprises
two check valves that control fluid flow under pressure exerted by
the reciprocating piston from a fluid reservoir to a point of use
of the fluid.
Inventors: |
Angove; Garret; (Osterville,
MA) |
Correspondence
Address: |
Paul J. Cook
115 Pine Street
Manchester
MA
01944
US
|
Family ID: |
35541561 |
Appl. No.: |
10/887623 |
Filed: |
July 12, 2004 |
Current U.S.
Class: |
417/415 ;
417/559 |
Current CPC
Class: |
F04B 13/02 20130101;
F04B 7/0003 20130101 |
Class at
Publication: |
417/415 ;
417/559 |
International
Class: |
F04B 53/10 20060101
F04B053/10; F04B 35/04 20060101 F04B035/04 |
Claims
1. A pump apparatus which comprises: a displacement pump for
pumping a fluid having a reciprocatable piston positioned within a
first housing having an interior wall spaced apart from said
piston, an interior volume of said first housing being in fluid
communication with a fluid inlet to a first check valve and a fluid
outlet from a second check valve, said first check valve being in
fluid communication with a point of use for said fluid, said second
check valve being in fluid communication with a source of said
fluid, said first check valve being open and said second check
valve being closed when said piston moves toward said first check
valve, said first check valve being closed and said second check
valve being open when said piston moves away from said first check
valve.
2. The pump apparatus of claim 1 wherein said housing is formed of
a transparent material.
3. The pump apparatus of claim 1 wherein said piston is formed of
sapphire.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to an integrated pump and check valve
apparatus for pumping discrete liquid volumes to points of use of
the liquid volumes. More particularly, this invention relates to an
integrated displacement pump and check valve apparatus for pumping
discrete liquid volumes to points of use.
[0002] At the present time, discrete liquid volumes are pumped with
a syringe pump comprising a barrel, a face seal which moves within
the barrel and a reciprocating plunger attached to the face seal.
The syringe pump includes a valve construction formed of a
polymeric composition which directs the pumped liquid volumes to a
point of use. The valve construction includes a housing (stator)
having a hollow, essentially interior surface into which is press
fit a mating rotor. The rotor is provided with fluid passageways
that control flow of liquid into the syringe pump and flow of
liquid from the syringe pump while providing sealing between a pump
inlet and a pump outlet. This configuration of syringe pump and
rotor-stator valve requires two motors, one to drive the syringe
and a second to drive the rotor.
[0003] While the available syringe pumps have been useful for their
intended purpose, they also have disadvantages. In order to attain
a tight fit between the barrel and the face seal, the manufacturing
of both the barrel and face seal must be made at tight tolerances.
In addition, when utilizing the most commonly used materials
comprising a glass barrel and a polytetrafluoroethylene (PTFE) face
seal, undesirable shedding of the PTFE occurs which contaminates
the liquid being pumped. Furthermore, a tight fit between the
barrel and face seal results in chattering of the face seal during
its movement within the barrel. This leads to a loss of control of
the liquid volume being pumped. In addition, the average useful
life of presently available syringe pumps is only about 10 to about
100,000 cycles.
[0004] Accordingly, it would be desirable to provide a pump
apparatus capable of delivering discrete liquid volumes to a point
of use such as different areas of a sample tray in a manner which
is repeatable for long time periods of 1,000,000 cycles or more. In
addition, it would be desirable to provide such a pump apparatus
which avoids shedding of polymeric particles during pumping.
Furthermore, it would be desirable to provide such a pump which
eliminates the need for a motor to activate a seal in order to
direct fluid to a desired point of use.
SUMMARY OF THE INVENTION
[0005] The present invention provides a pumping apparatus
comprising (a) a displacement pump having a liquid displacement
element comprises a piston housed within a barrel, a high pressure
seal and means for reciprocating the piston within the barrel and
(b) check valves wherein the sealing is effected by activating a
movable element under pressure of fluid being pumped without use of
a motor. Liquid in the barrel is delivered to a point of use while
the piston is traveling toward a check valve positioned between the
piston and the point of use and liquid is supplied to the barrel
when the piston is traveling away from the check valve positioned
between the piston and the point of use. The moving piston is
spaced apart from the inside surface of the barrel so that a
frictional force between the piston and the barrel is prevented
during pumping. By providing check valves between the piston and
(a) the point of use and (b) a source reservoir for the liquid,
motors for positioning the valves can be eliminated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a side view of the displacement pump and check
valve apparatus of this invention.
[0007] FIG. 2 is a front view of the apparatus of FIG. 1.
[0008] FIG. 3 is a cross-sectional view of the apparatus of FIG. 2
taken along line 3-3 of FIG. 2.
[0009] FIG. 4 is a cross-sectional view of a check valve useful in
the present invention.
DESCRIPTION OF SPECIFIC EMBODIMENTS
[0010] Referring to FIGS. 1, 2 and 3, the pump apparatus 10 of this
invention includes a housing 12 and a motor 16 which effects
rotation. Housing 32 which can be formed of an opaque or
transparent material which is resistant to the liquid being pumped
such as acrylic, polyetherether ketone, or the like can be a single
piece or a plurality of joined elements. The piston 34 can be
formed of sapphire, glass or a ceramic or the like and is spaced
apart from the interior wall 38 of housing 32. When the piston 34
is so-positioned, a single stroke of the piston 34 during use of
the pump will deliver a known volume of liquid depending upon the
piston diameter and the stroke length. As shown in FIG. 1, the
housing 32 for the check valve 45 and the piston 34 can be formed
of a single element. The provision of this single element housing
provides the advantage that the valve seats and displacement pump
of this invention can be replaced simultaneously after the useful
life of the pump is completed.
[0011] Motor 16 causes gear box 40 to reciprocate through pulley
41, and gears 42, 44 and 46 and gear track 48. Gear box 40 is
positioned within track 47 which causes the piston 34 to move in a
repeatable linear path stroke after stroke. As shown in FIG. 1, the
stroke of the pump varies from position 50 and position 52 which
typically can be between about 1.5 and 2.0 inches. It is to be
understood that any conventional activating apparatus which causes
piston 34 to reciprocate on a linear path can be utilized in the
present invention.
[0012] The piston 34 is positioned within seal 56 which can be
formed, for example of ultra high molecular weight polyethylene
(VHMWPE) or the like and optional roulon guide 58. The roulon guide
aligns piston 34 into seal 56. The piston 34 reciprocates within
seal 56 and roulon guide 58. The piston 34 is fixedly positioned in
ferrule 60 which, in turn, is fixed within arm 62 by knob 64.
[0013] As shown in FIGS. 2 and 3, the housing 32 can be formed of
two pieces comprising piece 32b and 32a. Housing piece 32b includes
two valve seats 31 and 33 into which are positioned check valves 35
and 37. Check valves 35 and 37 can have threads 39 and 41 to screw
the valves 35 and 37 into valve seats 31 and 33 having internal
threads (not shown). Housing 32b can be provided with threads 49
and 45 to secure housing 32b to housing 12. Check valve 35 is
connected to conduit 45, which in turn is in fluid communication
with a point of use for the fluid (not shown). Check valve 37 is
connected with conduit 47 which, in turn, is connected to a
reservoir for the fluid (not shown). In use, when piston 34 moves
toward check valve 35, check valve 35 is open and check valve 37 is
closed so that fluid is delivered through check valve 35 and
conduit 45 to a point of use of the fluid. When piston 34 moves
away from check valve 35, check valve 35 is closed and check valve
37 is open so that fluid moves into barrel 38 through check valve
37 and conduit 47 from a fluid reservoir.
[0014] Referring to FIG. 4, the valve 35, like valve 37 includes a
movable ball 70 which moves within valve seat 72 to block either
conduit 74 or conduit 76 to effect fluid flow as described
above.
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