GB2033967A

GB2033967A - Improvements in or Relating to Pumping Devices

Info

Publication number: GB2033967A
Application number: GB7933379A
Authority: GB
Original assignee: SECR DEFENCE; UK Secretary of State for Defence
Current assignee: SECR DEFENCE; UK Secretary of State for Defence
Priority date: 1978-10-03
Filing date: 1979-09-26
Publication date: 1980-05-29
Also published as: GB2033967B

Abstract

A pump for supplying air to a patient is operable either manually, or automatically by a pulsating gaseous pressure supply. The pump comprises a flexible outer membrane 3 which envelops a self-expanding inner membrane 2 to form a chamber 4 therebetween. Pulsating pressure is applied to the chamber 4 thereby to expand and contract the pumping chamber within the inner membrane 2. The inner membrane 2 has inlet and outlet valves 5 and 6. The pump can be operated manually by the application and release of pressure to the outer membrane 3. <IMAGE>

Description

SPECIFICATION Improvements in or Relating to Pumping Devices The present invention relates to pumps, and is particularly concerned with patient ventilators and the delivery of ambient air to a patient.

Hithertofore, most hospitals have encountered difficulties in patient ventilation because of the lack of availability of an acceptable air supply. A 100% oxygen supply is always available for short term ventilation but if a patient is to be ventilated for a considerable period, then that patient must be ventilated using air with the controlled addition of oxygen.

Supply air which is normally available in hospitals is produced by orthodox compressor systems. Such air contains impurities and is unfit for human consumption. It can only be purified at considerable expense.

Furthermore, in respect of patient ventilation a problem arises when a ventilator is switched off or removed from the patient and ventilation has to be provided manually. In such circumstances a resuscitation bag has to be introduced into the respiratory supply system, which is time consuming and deleterious to the patient's condition.

By the present invention, the patient can, whatever type of ventilator is used, breathe ambient air which is acceptable to him. The invention obviates the need for expensive purification equipment and may be operated either manually, or automatically from a ventilator.

According to the present invention a pump .

drive comprises a vented pumping member and a deformable driving member, the pumping member including a deformable and selfexpanding driven member which at least partially overlaps the driving member to form a chamber therebetween, the driving member adopted, in use, to receive gas from a reciprocating gas supply and to generate a pumping action in the driven member.

According to a feature of the present invention the driven member is within the driving member and the driving member is sufficiently inelastic to allow the pressure within the chamber to rise and fall to compress and release the driven member, yet pliant enough to permit manual deformation of the driven member. Preferably the driving member is self-expanding.

According to a preferred feature of the present invention the driving member and the driven member are bladders. Such bladders are preferably of an ovoid form with the driven member arranged co-axially within the driving ~member.

According to a further preferred feature of the invention the pump drive is of a size suitable for one-handed operation.

The invention is appropriate to patient resuscitation and a pump including the pump drive may be arranged to feed ambient air into the lungs of a patient by having an inlet valve which permits the passage of ambient air into the pumping member when the pressure therein is below atmospheric. The pump may include an air filter which may be attachable to the external portion of the inlet valve so that any ambient air which would otherwise be unfit for human consumption can be rendered acceptable for patient resuscitation.

A pump in accordance with the invention will now be described by way of example with reference to the following figures of which: Figure 1 shows the pump functioning on the compression stroke of the ventilator, and Figure 2 shows the pump functioning on the filling stroke of the ventilator.

With reference to Figures 1 and 2, the pump comprises a resuscitation bag 1 having a deformable driven member 2 which is selfexpanding and which is enclosed within a deformable driving member 3 to form a potential space 4. The driving member 3 has restrained outer dimensions so as to restrict expansion of the driven member 2.

The resuscitation bag 1 includes an inlet valve 5 designed to permit ambient air to enter when the pressure within is below ambient pressure.

Oppositely mounted from the inlet valve 5 is an outlet valve 6 which is designed to open when the pressure within the bag 1 is greater than that within a delivery tube 7. The delivery tube is linked to the respiratory system of the patient and includes an expiratory valve 8 to permit a patient to exhale to the surroundings.

The driving member includes a projecting tube 9 for connecting to a ventilator 10.

As shown in Figure 1 compressed gas is delivered into the potential space 4 when the ventilator 10 is operating on the compression stroke. The pressure of the gas is maintained by the dimensionally stable response of the driving member 3 and reacts to compress the driven member 2 In consequence the pressure within the bag 1 is raised sufficiently to cause the outlet valve 6 to open, thereby driving the air already within the bag into the lungs of a patient via the delivery tube 7.

As shown in Figure 2, the filling stroke of the ventilator 10 causes the gas to escape from the potential space 4 through the ventilator expiration port, the gas being driven by the spontaneous return of the pumping member to its maximum dimension. The expansion of the driven member 2, due to its natural resilience, also causes a pressure drop within the bag 1 allowing ambient air to be drawn through the inlet valve 5 into the bag. This air may be delivered to the patient on the compression stroke of the ventilator 1 0.

If removal of the ventilator is required for physiotherapy or because of failure of the ventilator, the bag can be compressed by hand and will operate as if the driven member 2 alone were pressed.

The pump operating apparatus can be driven on any gas supply and may incorporate a simple filter arrangement prior to the inlet valve 5. This will enable the apparatus to be used in circumstances where the ambient air would otherwise be unacceptable. The induced back pressure resulting from the addition of the filter may be met by increasing the stiffness of the pumping member 2.

In a preferred form the driving member 3 and the driven member 2 will be produced from transparent or translucent plastics material to enable the operation of the apparatus to be observed.

In an alternative form the driving member may be within the driven member.

Claims

1. A pump drive comprising a vented pumping member and a deformable driving member, the pumping member including a deformable and self-expanding driven member which at least partially overlaps with the driving member to form a chamber therebetween, the driving member adopted, in use, to receive gas from a reciprocating pressure supply and to generate a pumping action in the pumping member.

2. A pump drive as claimed in claim 1 and wherein the driven member is within the driving member and the driving member is sufficiently inelastic to allow the pressure within the chamber to rise and fall to compress and release the driven member, yet pliant enough to permit manual deformation of the driven member.

3. A pump drive as claimed in claim 2 and wherein the driving member is self-expanding.

4. A pump drive as claimed in any one of the preceding claims and wherein the driven member is a bladder.

5. A pump drive as claimed in any one of the preceding claims and wherein the driving member is a bladder.

6. A pump drive as claimed in claim 4 or claim 5 and wherein the bladder or bladders are ovoid in form.

7. A pump drive as claimed in any one of the preceding claims and wherein the driving member and the driven member are substantially symmetrical about the same axis.

8. A pump drive as claimed in any one of the preceding claims and which is of a size suitable for one handed operation.

9. A pump drive as claimed in any one of the preceding claims and wherein the pumping member is of transparent or translucent plastics material.

10. A pump drive as claimed in claim 9 and wherein the driven member is of transparent or translucent plastics material.

11. A pump drive as claimed in any one of the preceding claims and including inlet and outlet vents.

12. A pump including a pump drive as claimed in claim 1 1 and wherein the inlet vent houses an inlet valve and the outlet vent an outlet valve such that compression or expansion of the driving member causes fluid to be expelled from the driven member via outlet valve, and release thereof causes fluid to be drawn into the driven member via the inlet valve.

13. A pump as claimed in claim 12 for use in supplying ambient air for patient ventilation, and wherein the inlet vent is open to the atmosphere and includes an air filter.

14. A pump as claimed in claims 12 or 13 and wherein the reciprocating pressure supply is provided by a patent ventilator.

15. A pump substantially as hereinbefore described with reference to Figure 1 and Figure 2.