IES20080930A2 - A valve - Google Patents

Abstract

The present invention relates to a valve (1) for distributing compressed air to selective portions of an alternating pressure support device. The valvt; comprises a valve casing (2) defining an air chamber, and an air inlet port (3) to the air chamber for connecting the air chamber to a compressed air supply. The valve (1) further comprises a plurality of air outlet ports (5a-c) from the air chamber, each connectable to a selective portion of an alternating pressure support device for fluid communication therewith. The valve (1) is provided with a valve closure (13) adapted to move linearly of the air chamber to selectively close one or more of the air outlet ports (5), and drive means (11) operable to move the valve closure (13) within the chamber. The present invention also relates in further aspects to an air pump unit for supplying compressed air to an alternating pressure support device, and a patient support system for prevention of decubitus ulcers, respectively. <Figure 6>

Description

The present invention relates to valves for air pumps, in particular, valves for distributing compressed air to selective portions of an alternating pressure mattress.

Background to the Invention Bedsores, also known as pressure sores, pressure ulcers or decubitus ulcers, are lesions caused by unrelieved pressure on any part of the body. They can develop due to lying or sitting in one position for an extended period of time, and are therefore common in bedridden patients in hospitals and nursing homes. Due to the pressure on a particular part of the body, such as the back, elbows, knees or ankles, the blood supply to that area may be restricted or cut off, resulting in tissue damage known as a bedsore.

Alternating pressure (or ripple) mattresses are commonly used in hospitals and nursing homes, to prevent development of bedsores in bedridden patients. An alternating pressure mattress typically comprises several layers of flexible material forming a plurality oi' inflatable cells. The mattress is attached to an air pump which pumps air into the cells to inflate the mattress. The cells may be divided into groups or sections, and air pumped into one or more groups of cells at a time. This allows the pressure experienced by the patient lying on the mattress to be constantly redistributed.

Currently available air pumps for alternating pressure mattresses typically require solenoid valves to pump air with sufficient pressure to different sections of the mattress in a predetermined cycle. These valves are heavy and generate significant amounts of heat.

Summary of the Invention According to a first aspect of the invention, there is provided a valve for distributing compressed air to selective portions of an alternating p^essure^support deyice, such as a mattress or chair pad, comprising: 1 a valve casing defining an air chamber; IE Ο 8 Ο 9 3 ο an air inlet port to the air chamber for connecting the air chamber to a compressed air supply; a plurality of air outlet ports from the air chamber, each connectable to a selective portion of an alternating pressure support device for fluid communication therewith; a valve closure adapted to move linearly of the air chamber to selectively (or alternately) close one or more of the air outlet ports; and drive means operable to move the valve closure within the chamber.

Thus, the valve closure may selectively prevent the outflow of air from al least one outlet port. When an outlet port is closed by the valve closure, one of more of the other outlets may remain open. An advantage of the valve of the present invention is that it may be produced from lightweight plastic materials. Another advantage of the invention is that heat produced by the valve is significantly less than that produced by a solenoid valve.

Suitably, (he inlet port is arranged at a first side of the casing and the outlet ports are arranged at a second side of the casing, wherein the second side is opposite the flrsl side such that air Hows through the chamber from the first side to the second side. The valve closure may be arranged to move perpendicular to the direction of airflow.

Preferably, the valve closure is mounted for axial movement on a shaft that extends linearly of the air chamber. The drive means may be operable to drive the shaft such that the valve closure moves longitudinally of the shaft to selectively close one or more of the air outlet ports. In one embodiment, the shaft is screw-threaded and is mounted lor rotation within the chamber, and the shaft screw-threadedly engages with the valve closure, and the drive means is operable to rotate the shaft to cause the valve closure to move longitudinally of the shaft to selectively close at least one outlet port. In this embodiment, the valve closure may be provided with an internal screw-threaded bore JO that engages with the shaft.

Optionally, the valve closure is constrained to move linearly of the chamber by guide means located in the chamber. The guide means may comprise a linear guide extending IE Ο 8 Ο 9 3 ο longitudinally of the chamber to engage a portion of the valve closure. In various embodiments, the guide means comprises one or more of a channel, a groove, a track or a ridge.

The valve closure may be formed from a self-lubricating material, such as polytetralluoroethylene (PTFE).

Suitably, the drive means comprises an electric motor, and optionally the electric motor is a stepper motor. The drive means may be programmable to selectively close one or more of the outlet ports in a predetermined sequence.

In an embodiment, the valve closure comprises a sealing nodule. The sealing nodule may be adapted to seat within an outlet port to close the port. The air pressure within the chamber may assist in causing the nodule to seal the outlet The valve closure may further comprise a channel or groove provided around the sealing nodule to allow deflation of selective portions of an alternating pressure support device. This allows the air lo be released slowly from the mattress, thereby preventing reperfusion injury.

According to a second aspect of the invention, there is provided an air pump unit for supplying compressed air to an alternating pressure support device, including a compressed air supply and a valve as described above connected thereto. The air pump unit may be provided with controls to allow the sequence in which the outlet ports are closed to be programmed. The length of time for which each port is open and closed may also be programmed. The air pump unit may also be provided with an alarm, operable to indicate when a power supply has been disconnected from the unit. The air pump unit may also be provided with means for tracking usage of the pump, so that the user can be billed according to usage, for example, based on an hourly billing system.

A report ol pump usage may be obtained by connecting the pump unit to a computer having a suitable reporting program installed thereon. The pump unit may comprise a USB port for connection by means of a USB lead to a USB port on the computer. A report may be generated by following the steps of: a) initiating execution of the reporting program on the computer; IE Ο 8 Ο 9 3 ο b) identifying the pump unit to be reported, for example, by entering a unique device ID; ci downloading the usage log from the pump unit via the USB connection; d> optionally storing the usage log on the computer; c) generating a report including one or more of the customer name to which the pump unit is registered, the date and time of the report, the unique device ID and the total usage time.

The air pump unit may be used to supply compressed air to alternating pressure support l o devices such as alternating pressure mattresses or chair pads. The air pump unit may be operated in two modes. In the first mode, referred to as the static mode, all air cells are inJlated simultaneously, and there is no alternating pressure effect. This mode is useful for setup and patient movement. In the second mode, the cells are inflated and deflated according to a predefined sequence to give an alternating variable pressure effect.

According to a third aspect ofthe invention, there is provided a patient support system lor prevention of decubitus ulcers, comprising an air pump unit as described above and an alternating pressuresupport device, wherein each air outlet port of the valve is connected to a portion of the alternating pressure support device for fluid communication therewith. The alternating pressure support device may be, for example, a mattress or a chair pad.

Brief Description of the Drawings f igure 1 is a rear elevation view of a first embodiment of a valve according to the present invention; Figure 2 is a lop plan view of the outer casing of the valve of Figure 1; Figure 3 is a front elevation view of the valve of Figure 1; Figure 4 is a left side elevation view of the valve of Figure 1; Figure 5 is a right side elevation view of the valve of Figure 1; Figure 6 is a top perspective view of a second embodiment of the valve of the invention with the upper portion of the casing removed; Figure 7 is a front perspective view ofthe valve of Figure 6, with the hose connector removed: and IE Ο 8 Ο 9 3 Ο Figure 8 is a front perspective view of the plunger of the valve of Figure 6.

Detailed Description of the Drawings Λ valve 1 for distributing compressed air to selective portions of an alternating pressure mattress, according to an embodiment of the present invention is shown in Figures 1 to 5 of the drawings. The valve comprises an outer casing 2 defining an air chamber 17. Ihe valve I further comprises an air inlet port 3 to the chamber 17 at a rear portion 4 of the casing tor connection to a compressed air supply, such as an air blower or pump, The valve 1 further comprises three air outlet ports from the air chamber 17 at a front io portion 6 of the casing. Each of the outlet ports is connectable to a selective portion of an alternating pressure mattress for fluid communication therewith. A spacer 7 is provided at the front portion 6 of the casing 2 and a hose connector 8 having three nozzles 9a-c corresponding to the outlet ports is attached to the spacer 7. Each of the nozzles 9a-c is in fluid communication with the corresponding outlet port and is connectable to a portion of an alternating pressure mattress. f igures 6 and 7 show a valve 1 according to another embodiment of the invention, with the upper portion 10 of the outer casing 2 removed. Air outlet ports 5a-c provided at the front portion 6 of the casing 2 are shown. The valve further comprises a valve closure 13 adapted to move linearly of the air chamber 17 to selectively close one or more of the air outlet ports 5a-c, and a stepper motor 11 operable to move the valve closure 13 within the chamber. The valve closure 13 is mounted for axial movement on a shaft 12 that extends linearly of the air chamber 17, The stepper motor 11 is operable to drive the shaft 12 such that the valve closure 13 moves longitudinally of the shaft to selectively close one or more of the air outlet ports 5a-c. The shaft 12 is screw-threaded and is mounted for rotation within the chamber, and the shaft screw-threadcdly engages with the valve closure 13, which is provided with an internal screw-threaded bore that engages with the shaft. The stepper moior 11 is operable to rotate the shaft 12 to cause the valve closure 13 to move longitudinally of the shaft to selectively close at IcasL one outlet port 5a-c.

Ihe valve closure 13 is constrained to move linearly of the chamber by guide means, in the (oi m of a channel 16 extending longitudinally of the chamber 17 to receive a lower IE 0 8 0 9 3 0 portion of the valve closure 13. The upper portion 10 of the outer casing may also be provided with guide means on its inner surface, such as for example, a ridge, channel, track or groove.

The valve closure 13 is illustrated in more detail in Figure 8. As shown in the drawing, the front face of the valve closure is provided with a channel or groove 15. A raised circular portion or sealing nodule 14, which may be adapted to seat within an outlet port 5a-c to close the port, is provided in the centre of the front face of the valve closure.

The groove 15 allows deflation of selective portions of an alternating pressure mattress via vent 19 as will be described below.

In use, the air input port 2 of the valve I is connected to a compressed air supply, such as an air pump or blower. In one embodiment, the air supply and valve are provided together within an air pump unit. The unit is provided with controls to allow the sequence and timing at which the valve selectively distributes compressed air to selective portions of an alternating pressure mattress to be programmed. Each of the nozzles 9a-c is connected to a portion of the alternating pressure mattress for fluid communication therewith.

In a preferred arrangement, the nozzle 9a is connected to a lower portion of the mattress. 1 his lower portion of the mattress comprises a plurality of cells, referred to as static” cells. These cells are always supplied with compressed air during operation of the air pump unit. This ensures that the patient is supported and raised slightly, and prevents bottoming out”. Typically, an upper portion of the mattress is divided into an even” portion and an odd” portion. Each of the even and odd portions comprises a plurality of cells. The cells are arranged so that even and odd cells alternate over the surface of the mattress. Nozzle 9b is connected to the even portion of the mattress and nozzle 9c is connected to the odd portion of the mattress (or vice versa). The odd and even portions of the mattress are selectively provided with compressed air from the air pump unit in order to continually vary the pressure between the patient and the mattress, thereby preventing development of bedsores.

In one example, the valve is programmed for a four stage cycle as shown in the following table.

IE 0 8 0 9 3 0 Stage Port 5a Nozzle 9a Port 5 b Nozzle 9b Port 5 c Nozzle 9c 1 Open Open Open 2 Open Open Closed 3 Open Open Open 4 ..... Open Closed Open Other sequences are also possible.

For the sequence shown, the valve closure 13 begins in a position between port 5b and port 5e. as shown in Figure 6. The closure 13 is dimensioned so that compressed air may pass on either side ofthe closure and out of the valve via ports 5b and 5c into both to even and odd portions of the mattress. Compressed air is also supplied to the static portion ofthe mattress via port 5a. Next, the motor 11 drives the shaft 12, so thai the valve closure moves upwards to close port 5c. Air is supplied to the static and even portions ofthe mattress via ports 5a and 5b. Next, the motor 11 drives the shaft in the opposite direction, so that the closure 13 moves back to its initial position, so that compressed air is supplied to all portions of the mattress. For the final stage, the motor drives the shaft again so that the closure moves downwards to close port 5b. Air is supplied to the static and odd portions of the mattress via ports 5a and 5c.

When one ofthe ports is fully closed, the air from that portion of the mattress passes out ofthe cells, towards the valve 1. The air flows around the sealing nodule 14 and into the groove 15 on the front face of the closure 13. The groove 15 is in fluid communication with vent 19 on the front portion 6 of the casing 2, as shown in Figures 2.6 and 7 of the drawings. The air thus flows out of the cell, through the groove and out ofthe valve I via vent 19, thereby allowing that portion of the mattress to deflate, giving an alternating pressure effect.

IE Ο 8 ο 9 3 Ο 8 The words comprises/comprising”and the words “having/including” when used herein with reference to the present invention are used to specify the presence of staled features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. it is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Claims (14)

1. Λ valve (I) for distributing compressed air to selective portions of an alternating pressure support device, comprising: 5 a val ve casing (2) defining an air chamber (17); an air inlet port (3) to the air chamber (17) for connecting the air chamber to a compressed air supply , a plurality of air outlet ports (5a-c) from the air chamber (17 ), each connectable to a selective portion of an alternating pressure support device for fluid communication 10 therewith; a valve closure (13) adapted to move linearly of the air chamber (17) to selectively close one or more of the air outlet ports (5); and drive means (11) operable to move the valve closure (13) within the chamber (17).

2. A valve (1) as claimed in claim 1, wherein the valve closure (13) is mounted for axial movement on a shaft (12) that extends linearly of the air chamber (17).

3. A valve as claimed in claim 2, wherein the drive means (11) is operable to drive the 20 shaft (12) such that the valve closure (13) moves longitudinally of the shaft to selectively close one or more of the air outlet ports (5).

4. A valve as claimed in claim 3, wherein the shaft (12) is screw-threaded and is mounted for rotation within the chamber (17), and the shaft screw-threadedly 25 engages with the valve closure (13), and the drive means (11) is operable to rotate the shaft (12) to cause the valve closure to move longitudinally of the shaft to selectively close at least one outlet port (5).

5. A valve as claimed in claim 4, wherein the valve closure (13) has an internal screw30 threaded bore (18) that engages with the shaft (12). IE Ο 8 Ο 9 3 Ο

6. A valve as claimed in any preceding claim, wherein the valve closure (13) is constrained to move linearly of the chamber by guide means (16) located in the chamber. 5

7. Λ valve as claimed in claim 6, wherein the guide means comprises a linear guide (16) extending longitudinally of the chamber to engage a portion of the valve closure (B).

8. A valve as claimed in any preceding claim, wherein the valve closure (B) is formed 10 from a self-lubricating material.

9. A valve as claimed in any preceding claim, wherein the drive means comprises an electric motor, and optionally the electric motor is a stepper motor (11). 15

10.Λ valve as claimed in any preceding claim, wherein the drive means (11) is programmable to selectively close one or more of the outlet ports (5) in a predetermined sequence.

11. .A valve as claimed in any preceding claim, wherein the valve closure device includes 20 a sealing nodule (14) that is adapted to scat within an outlet port to close the port.

12. An air pump unit for supplying compressed air to an alternating pressure support device, comprising; a compressed air supply; and 25 a valve (1) according to any preceding claim connected thereto.

13. A patient support system for prevention of decubitus ulcers, comprising: an air pump unit according to claim 12; and an alternating pressure support device comprising a plurality of portions, 30 wherein each air outlet port of the valve is connected to a selective portion of the alternating pressure support device for fluid communication therewith. IE Ο 8 Ο 9 3 Ο

14. A valve for distributing compressed air to selective portions of an alternating pressure support device substantially as hereinbefore described with reference to and/or as illustrated in Figures 1 to 5 or Figures 6 and 7 of the accompanying drawings