GB2108211A - Fluid pump - Google Patents

Abstract

A vacuum powered fluid pump comprises a housing (10) defining a chamber (32) enclosing an elastic sleeve (16) which establishes a flow path from an inlet (12) to an outlet (14); a vacuum line connection to the chamber; and a vent valve (34) for the chamber. The pump is operable due to expansion of the sleeve under a reducing pressure due to evacuation of the chamber and check valves ensure unidirectional flow at the inlet (12) and at the outlet (14). The vent valve may alternatively comprise a hole actuated by finger closure. <IMAGE>

Description

SPECIFICATION Vacuum driven pulsatile pump This invention relates to a peristaltic pulsatile pump intended for use at relatively low pressure levels and more especially a pump which may be operated by connection to a vacuum source. The invention is useful particularly (although not exclusively) in medical environments, such as in operating rooms, where a source of vacuum is readily available at all times.

In medical and operating room environments, low flow output pumps which are operable in a pulsatile or peristaltic manner, have a variety of uses. For example, they can be used to draw fluids from closed wounds and to deliver the fluids to a storage receptacle. They may be used as stomach pumps.

Such a device may be used to collect blood and/or to effect transfusion from a donor to a donee. Low pressure, pulsatile pumps also are useful in kidney dialysis techniques to transfer blood to and from the dialysis machine. Low output pumps having a pulsatile, peristaltic mode of operation also are usable in connection with wound or organ irrigation and debridement.

It is a general object of the invention to provide a pump which develops a pulsatile, peristaltic action, which may be vacuum powered, and which is capable of displaying a gentle pumping action and is suited for use in medical and surgical environments were delicacy of pumping action is among the prime considerations.

The invention also aims to provide a pumping device of the peristaltic pulsating type which is operable both automatically as well as manually, and is of simple, inexpensive construction which lends itself to disposable use.

In accordance with the present invention, a simple yet effective device is provided and includes an expandable elastic element, preferably in the form of a sleeve, having an inlet end and an outlet end. The sleeve is contained within and extends through a relatively rigid vacuum chamber which is connectible to a vacuum source. The vacuum chamber surrounds the elastic sleeve so that when the vacuum is applied to the chamber the sleeve will expand. A check valve is located at each of the inlet and outlet ends of the sleeve to assure that flow through the sleeve will be unidirectional. When vacuum is applied, the reduced pressure surrounding the elastic sleeve causes the sleeve to expand as fluid is drawn in thorough the inlet through the open inlet check valve.

In an automatically operating embodiment of the invention, expansion of and ingestion of fluid into the elastic sleeve continues until the elastic sleeve has expanded to a predetermined size at which time the expansion of the sleeve triggers a valve which vents the vacuum chamber to the atmosphere. When the vacuum chamber vents, the elastic sleeve contracts, thereby shutting the inlet check valve and forcing the fluid from the elastic sleeve through the outlet check valve and into the delivery line. The resilient collapse of the elastic sleeve also closes or enables closing of the venting valve to enable the suction to begin a new pumping cycle.

The invention also includes manually operable embodiments of the invention by which the frequency and extent of pumping action is controllable manually.

Further features of the invention will be appreciated more fully from the following description thereof, making reference to the accompanying drawings wherein: Figure 1 is a broken-away diagrammatic illustration of the device; Figure 2 is a longitudinal section of the device illustrating the manner in which the elastic element expands to ingest fluid; Figure 3 is an illustration similar to Fig. 2.

diagrammatically illustrating the device when it vents to the atmosphere to effect a pulsatile pumping action of the elastic element; Figure 4 is an illustration of a modification to the device shown in Figs 1-3 by which the automatic venting action can be manually overridden and controlled; Figure 5 is an illustration of a completely manually operable embodiment of the invention.

Fig. 1 illustrates diagrammatically the functional elements of an automatically operable embodiment of the device. The device includes a rigid housing 10 which may be moulded from plastic or the like. The housing may take any of a variety of shapes, depending in part of the particular environment and manner in which the device is to be used. For example, only the housing may take the form of a conveniently hand-held elongate device or may take the form of a cannister to which various lines, hoses and nozzles may be connected. The housing 10 in the illustrative embodiment includes an inlet end 1 2 and an outlet end 14. An elastic sleeve 1 6 extends through the housing 10 from the inlet end 1 2 of the housing 10 to the outlet end 14.The ends of the elastic sleeve 1 6 are hermetically sealed to the inlet and outlet ends of the housing, illustrated diagrammatically by everted ends 18 of the elastic sleeve 1 6.

A check valve 20, 22 is associated with each of the inlet and outlet ends of the device. The inlet check valve 20 is selected to permit flow only from the inlet 1 2 into the elastic sleeve 1 6 and the outlet valve 22 is arranged only to permit flow from the elastic sleeve 1 6 to the outlet 1 4. The check valves 20, 22 may be of any convenient design consistent with the intended use of the de vice. For example, they may be ball check or duck bill valves, mounted in tubing connectors 24, 26 which define the inlet and outlet.

The housing is provided with a fitting 28 which is connectible to a vacuum line which, in turn, may be connected to a vacuum source as is conveniently found in an operating room or other hospital or surgical environment. The vacuum line preferably is provided with a variable restrictor valve (not shown) to shut off or restrict the rate of evacuation from the vacuum chamber of the device.

From the foregoing, it will be appreciated that the interior of the housing 10 may be considered as defining a variable volume pumping chamber 30 (defined by the interior volume of the elastic sleeve 16) and a surrounding or annuiar vacuum chamber 32. In operation, as a vacuum develops in the vacuum chamber 32, the elastic sleeve will expand, ingesting and drawing fluid into the pumping chamber 30 through the inlet tube and the check valve 20. During this mode of operation, the outlet check valve 22 remains closed, The volume which will be ingested and pumped by the pump chamber 30 is a direct function of the extent to which the sleeve 1 6 is permitted to expand.To that end, the device includes a relief valve 34 which is located on the housing 10 so as to be tripped by the transversely expanding sleeve 1 6 when the pump chamber 32 has reached a predetermined volume. In the diagrammatic illustrative embodiment of the invention, the relief valve 34 is mounted in the chamber housing 10 and extends through a vent opening 36 formed in the housing 1 0. The valve 34 includes a valve element 38 which is illustrated as being in the form of a pad. The valve element 38 cooperates with a valve seat 40 which surrounds the vent 36. The valve element 38 normally bears against the valve seat 40 to maintain the valve opening 36 closed as shown in Figs. 1 and 2. The valve arrangement 34 also includes an inwardly extending valve stem 42 which extends inwardly from the valve member 38 through the opening 36.The inner end of the valve stem 42 terminates in a valve pad 44 which is engageable by the transversely expanding elastic sleeve 1 6. The valve may be biased in its closed, seated relation on the valve seat 40 by a supplemental spring or biasing means, as illustrated diagrammatically by the leaf spring 46. From the foregoing, it will be appreciated that when the elastic pumping chamber 30 has expanded to a predetermined size, it will engage the valve pad 44 and continued expansion of the sleeve will shift the valve 44 to open it and permit atmospheric air to rush in through the valve opening 36.The magnitude of vacuum and the size of the valve opening 36 may be selected so that the rate of admission of air through the valve opening 36 will be sufficiently greater than the rate of air flow through the vacuum line as to enable the elastic sleeve to return to its reduced volume within a predetermined time interval. Thus, by adjusting these parameters, the characteristics, such as frequency, of the pulsatile pump action can be varied.

When the valve opens, the elastic nature of the sleeve causes the sleeve to constrict, thereby forcing fluid contained in the elastic pumping chamber 30, outwardly through the outlet check valve 22 and into the outlet tube 14. When the elastic pump chamber 30 has contracted to an extent at which the relief valve 34 can reciose, the cycle begins anew.

From the foregoing, it will be appreciated that the device is usable either or both as a suctioning device or as a fluid delivery device.

The device may be used in closed wound suctioning, for example, of the abdominal cavity, in which the inlet 24 may be connected to a conventional closed-wound drainage tube and the level of the vacuum in the vacuum line and rate of evacuation from the chamber adjusted to provide the desired suctioning and pumping effect. Alternately, the device could be used as a stomach pump to effect gentle, yet firm peristaltic pumping of material from the patient's stomach. As an output delivery device, the inlet tube may be inserted into a sterile irrigating or debridement solution and the outlet end may be connected to a tube which in turn is provided with a suitable nozzle or shower-like element at its outlet end.The fluid pumping action is suited particularly to those situations where it is important to have a gentle action and where high speed, forceful, high frequency jets are undesirable, as for example, when the surface of delicate organs or delicate wounds are being cleaned. In this regard, it may be noted that the pumping pressures utilized in the present invention may be relatively low, and typically may be well under one atmosphere.

This results from the ability of the device to be operated between a low pressure equal to the maximum vacuum available at the particular source and atmospheric pressure. During operation of the device, the vacuum within the vacuum chamber may be varied between atmospheric and a selected level of vacuum, as desired.

Fig. 4 illustrates a modification to the device in the form of an aperture 50 formed in the the housing 10 at a convenient location where it can be covered or uncovered by the user's finger. The provision of the opening 50 in the housing 10 provides the user with a convenient on-off control. The device may be disabled, effectively to an "off" configuration by uncovering the hole 50 thereby continuously venting the chamber 32 to the atmosphere.

When it is desired to resume operation of the device, the aperture 50 need only be covered to enable the vacuum to be developed within the chamber 32. In addition to providing an on-off control, the aperture may be selectively blocked or unblocked to vary frequency of operation of the automatic valving arrangement by varying the extent to which the aperture is obstructed. Additionally, the aperture may be covered or uncovered at a rapid rate, faster than the normal, automatic frequency of operation of the device, thereby providing substantially, completely manual mode of operation.

In some instances, it may be preferable simply to provide a device which is completely manually operable. Fig. 5 illustrates a device which is essentially the same as that discusses previously except that it completely omits the automatic valving arrangement and, instead, provides simply a manually controllable aperture. Here, the frequency is completely controlled by the user by opening and ciosing the aperture 50, to an extent and at a rate which suits the particular needs and requirements of the moment.

In addition, it will be appreciated that the various embodiments of the invention are relatively simple in construction and operation and, as such, lend themselves to disposable use.

It should be understood that while the foregoing description of the invention is intended to be diagrammatic and illustrative only, other embodiments, modifications and uses may be apparent to those skilled in the art without departing from the spirit of the invention.

Claims (15)

1. A peristaltic pulsatile pump comprising: a hollow elastic member having an inlet and an outlet end defining the flow path between the inlet and the outlet; a variable pressure chamber, the elastic member being confined at least in part by the pressure chamber and being hermetically sealed with respect to the pressure chamber; means for effecting oscillatory variations in the pressure within the chamber; and check valve means for effecting unidirectional flow along the flow path.

2. A device as defined in claim 1 further comprising: means for varying the pressure within the chamber within a range no greater than one atmosphere of pressure.

3. A device as defined in claim 1 wherein the means for effecting said oscillatory pressure variations is constructed and arranged so as to be operable automatically.

4. A device as defined in Claim 1 wherein the means for effecting said oscillatory pressure variations comprises manually operable means.

5. A peristaltic pulsatile pump comprising: a housing defining a vacuum chamber and having an inlet and an outlet end; an elastic member extending from the inlet end to the outlet end of the chamber and separating the chamber into vacuum chamber and a pumping chamber, the vacuum chamber surrounding the pumping chamber; means for connecting the vacuum chamber to a source of vacuum; check valve means associated with each of the inlet and outlet ends of the device to effect unidirectional flow therethrough; and vent means associated with the chamber to enable admission of atmospheric air into the chamber, thereby disrupting the expansion of the elastic member and enabling the resilience of the elastic member to effect a pumping action on the material within the elastic member.

6. A device as defined in claim 5 further comprising: said vent means being openable in response to the expansion of the elastic sleeve and closeable in response to contraction of the elastic sleeve.

7. A device as defined in claim 6 further comprising secondary manually operable vent means for selectively venting the chamber to the atmosphere.

8. A device as defined in claim 7 wherein said secondary means comprises a manually, obstructible hole formed in the housing, independently of the first vent means.

9. A device as defined in claim 5 further comprising: said vent means being manually operable.

10. A device as defined in claim 9 wherein said vent means comprises an aperture formed in the housing to enable the chamber to be selectively vented to the atmosphere.

11. A pump as defined in claim 6 further comprising: said elastic member being constructed so as to be expandable in a direction which extends transversely of the direction of fluid flow therethrough; said vent means including actuating means mounted on the housing at a location so as to be engaged by the transversely expanding elastic member.

1 2. A pump as defined in claim 11 wherein the vent means further comprises: valve means formed in the housing to communicate the vacuum chamber with the atmosphere; said valve means including an actuating member located so as to be actuated in response to transverse movement of the elastic member.

1 3. A device as defined in claim 1 2 further comprising: means biasing the vent valve in a normally closed configuration.

14. A device as defined in claim 5 further comprising: the housing being elongate in configuration thereby to define an easily manipulable handle shape.

15. A device as defined in claim 14 wherein the outlet end includes a tubular connector to enable various nozzle configurations to be detachably connected.

1 6. A device as defined in claim 5 wherein the housing includes at least a portion which is transparent thereby to enable the action of the resilient element to be observed.

1 7. A peristaltic pulsatile pump substantially as hereinbefore described with reference to the accompanying drawings.