GB2111174A - Depth responsive gas control device - Google Patents

Abstract

A device, for automatically opening a gas supply valve when the device reaches a predetermined depth, e.g. when diving, has a gas reservoir 1, a pressure sensing means e.g. diaphragm 14 providing a control signal when the ambient pressure exceeds that of the gas reservoir, and a supply valve 12 which is opened upon receipt of that signal. Underwater buoyancy apparatus, for use for example by a diver, has a buoyancy chamber to which gas can be supplied to alter buoyancy, and the device is incorporated between a gas supply and the buoyancy chamber to give automatic increase of buoyancy when a predetermined depth is reached. <IMAGE>

Description

SPECIFICATION A depth responsive gas control device This invention relates to a gas control device which is responsive to reaching a predetermined depth, in ambient fluid, for opening a valve controlling a supply of gas. It is of particular utility in, but is not restricted in its use to, providing increase of buoyancy in underwater buoyancy apparatus.

By way of illustration, it is important that a diver should not exceed the maximum depth to which he intends to dive. However, it is often difficult for a diver to ensure that this intended maximum depth is not exceeded. For example, the underwater visibility may be so limited that the diver cannot read a depth gauge attached to his wrist. Further, the diver may become distracted or have his judgement impaired during diving so that he does not appreciate, or perhaps, care that the intended maximum depth has been exceeded.

A first object of the invention is to provide a gas control device which is responsive to reaching a predetermined depth in ambient fluid to automatically open a valve controlling a supply of gas.

A second object of the invention is to provide underwater buoyancy apparatus, of the kind having a buoyancy chamber to which gas may be supplied to increase buoyancy of the apparatus, incorporating such a device for controlling said supply, such that for example a diver carrying the buoyancy apparatus will be prevented, by automatic increase of the buoyancy of the apparatus, from exceeding the intended maximum depth.

According to the present invention a device, for automatically opening a gas supply valve when the device reaches a predetermined depth in a fluid, comprises a gas reservoir, a pressure sensing means monitoring the difference in pressure between gas in said reservoir and the ambient fluid, said sensing means providing a control signal when the pressure of the ambient fluid exceeds the pressure of the gas reservoir, and a gas supply valve which is responsive to said signal to become opened.

Usually, but not necessarily, the gas reservoir will be a fixed volume reservoir, and conveniently it can be constituted by a cylindrical gas chamber.

Preferably means are provided for adjusting the pressure of gas in said gas reservoir, so as to vary the depth at which the valve means is actuated.

Said pressure adjustment means is conveniently in the form of a tyre inflation valve of the Schrader type.

Preferably the pressure sensing means comprises a flexible diaphragm which has one major surface exposed to the ambient fluid and which has its other opposed major surface exposed to the gas of the gas reservoir.

Conveniently the gas reservoir has a wall with an opening or openings therein, and said diaphragm is mounted on said wall covering the or each said opening.

When the pressure sensing means comprises a diaphgram as mentioned above, the control signal may be provided by movement of a rigid actuating member extending from and movable with said diaphragm, said actuating member acting directly or indirectly on said gas supply valve. For example, the actuating member may act on electrical, hydraulic, pneumatic or mechanical switching means controlling the gas supply valve.

Conveniently the gas supply valve is disposed within the gas reservoir, whereby the dimensions of the control device can be kept relatively small.

The valve would normally remain closed until the device reaches a predetermined depth in the ambient fluid. However, over-ride means may be provided for acting on said gas supply valve to open it independently of provision of said signal, e.g. for opening the valve at depths less than the maximum depth determined by the pressure of the gas in the reservoir Further according to the invention there is provided underwater buoyancy apparatus comprising the device as set forth herein and a buoyancy chamber connected to receive, from the gas supply valve, gas to increase the buoyancy of the apparatus. The buoyancy apparatus might be that carried by a diver, but the invention is applicable also to buoyancy apparatus for other purposes, for example for use with an underwater vehicle.

The following is a description, by way of example only and with reference to the accompanying drawings, of a presently preferred embodiment of the device, and of a buoyancy apparatus incorporating the device.

In the drawings: Fig. 1 is a diagrammatic cross-sectional view, of a gas supply valve opening device, taken on the line AA of figure 2; Fig. 2 is a side elevation of the device of figure 1; Fig. 3 is a plan view of the device of figure 1; Fig. 4 is an underplan view of the device of figure 1; Fig. 5 is a schematic diagram of a buoyancy apparatus incorporating the device.

Referring to the drawings, a gas reservoir, generally indicated at 1 is formed hy a short length of cylindrical tube 2 closed at each end by base caps 3, 4. The upper base cap 3 has a plurality of axial holes 5 extending therethrough.

These holes are arranged in a ring concentric with the base cap. A further axial hole 6 extends through the centre of the base cap 3. The lower base cap 4 is provided with a Schrader-type tyre inflation valve 7 through which air can be admitted into or discharged from the reservoir 1 via a pipe 7a. An air supply pipe 8 extends through the base cap 4 to a poppet valve 9 which is attached to and depends from the centre of the upper base cap 3. An air outlet pipe 10 also extends through the base cap 4 to communicate with the outlet of the valve 9. A relief valve 11 is provided within the reservoir 1 to permit discharge of air from the reservoir through the pipe 10 if the air in the reservoir exceeds a predetermined maximum pressure. For example, said pressure can be in the range 80 to 100 Ibs.

per square inch.

An operating stem 12 of the valve 9 extends through the central hole 6 in the base cap 3 to protrude from the upper surface of the base cap.

The protruding end of the stem 12 is threaded and is threadably received in the base of a coaxial spindle 13. The base of the spindle is secured to a lower diaphragm 14 which extends radially beyond the ring of holes 5. The periphery of the diaphragm 14 is clamped in fluid tight manner between the base cap 3 and an upper cylindrical tube 1 5 threadably connected thereto.

The tube 1 5 has a plurality of circumferentially spaced holes 1 6 to permit ingress of water.

The other end of the spindle 13 is secured to the centre of a second diaphragm 1 7 which is secured at its periphery between the upper tube 1 5 and a top cap 18 threadably received thereon.

This second diaphragm 17 is provided to stabilise the action of the lower diaphragm 14. The top cap 1 8 has several holes 1 9 extending axially therethrough to allow ingress of water into the chamber formed between the upper diaphragm 1 7 and the top cap 1 8. In that manner, both surfaces of the upper diaphragm 7 are exposed to the same water pressure. Strengthening ribs 1 8a are provided on the top cap 1 8.

Optionally, a threaded bore 20 is formed through the centre of the top cap 18 to receive a manually operable turn screw 21. The lower end of the turn screw 21 is aligned with the upper end of the spindle 1 3 whereby clockwise rotation of the turn screw causes the screw to bear down on the spindle.

The depth at which the limiting valve is to operate is determined by the pressure of air within the reservoir 1. Air is introduced into the reservoir 1 by, for example, a foot pump or compressed air line attached to the pipe 7a. If the pressure exceeds the maximum intended operating pressure, the relief valve 11 operates to exhaust air through the outlet pipe 10. Air pressure within the reservoir 1 can be adjusted as required, e.g. before each dive.

Referring to figure 5, the air inlet pipe 8 of the device of figures 1-4, denoted by reference 22, is connected to a source 23 of low pressure air of a self-contained underwater buoyancy apparatus to be carried by a diver. A suitable apparatus is that described in U.K. Patent No. 1484347 or No.

1 523195 the disclosure of which is incorporated herein by reference. The outlet pipe 10 of device 22 is connected to the buoyancy chamber 23 of the buoyancy apparatus.

During storage or normal use, the air pressure within the reservior 1 acting on the lower surface of the lower diaphragm 14 is greater than the ambient fluid pressure acting on the upper surface of the diaphragm 14. As a result, the diaphragm 14, when viewed from below, is maintained in a concave configuration and the stem 12 is maintained in an extended position whereby the valve 9 is closed isolating the inlet pipe 8 from the outlet pipe 10. However, when a depth is reached at which the water pressure exceeds the reservoir air pressure, the diaphragm 1 4 will be flattened by the excess water pressure thereby moving the stem 12 downwardly and opening the valve 9.

When the valve 9 opens air is permitted to pass from the inlet pipe 8 through the outlet pipe 10 and hence into the buoyancy chamber 23. The resultant increase in buoyancy causes the diver to rise to a lesser depth thereby reducing the water pressure on the diaphgragm 14. When the water pressure has been reduced to a pressure below that of the air in the reservoir 1, the diaphragm 14 will again adopt its concave configuration moving the stem 12 upwardly and thereby once again closing the valve 9.

If it is required to manually actuate the device, the turn screw 21 is turned clockwise to abut and depress the spindle 1 3 thereby forcing the stem 12 downwardly and opening the valve 9.

Counterclockwise movement of the turn screw 21 will release the spindle 13 permitting it to return to its normal position in response to movememt of the diaphragm 14.

It is an advantage if the gas reservoir 1 can be made of small dimensions, for compactness of the device. If the reservoir is made of small capacity the device becomes more sensitive to the pressure put into the reservoir. A very convenient way of applying pressure to the reservior, where the device is being used in conjunction with a diver's ordinary diving apparatus including (i) an air cylinder (ii) a first stage of a conventional regulator, and (iii) a second stage of a conventional regulator, is to have a second line from the second stage of the regulator with a pressure gauge incorporated in the line. It is then possible to insert air into the device with great accuracy.

It will be appreciated that the invention is not restricted to the particular details described above but that numerous modifications and variations can be made without departing from the scope of the invention.

Claims (11)

Claims

1. A device, for automatically opening a gas supply valve when the device reaches a predetermined depth in a fluid, comprising: (i) a gas reservoir, (ii) pressure sensing means monitoring the difference in pressure between gas in said reservoir and the ambient fluid, said sensing means providing a control signal when the pressure of the ambient fluid exceeds the pressure of the gas reservoir, (iii) a gas supply valve which is responsive to said signal to become opened.

2. A device, as claimed in Claim 1, comprising means for adjusting the pressure of gas in said gas reservoir.

3. A device, as claimed in either of Claims 1 and 2, wherein said pressure sensing means comprises a flexible diaphragm which has one major surface exposed to the ambient fluid and which has its other opposed major surface exposed to the gas of the gas reservoir.

4. A device, as claimed in Claim 3, wherein the gas reservoir has a wall with an opening or openings therein, and said diaphragm is mounted on said wall covering the or each said opening.

5. A device, as claimed in either of Claims 3 and 4, comprising a rigid actuating member extending from and movable with said diaphragm, said actuating member acting directly or indirectly on said gas supply valve.

6. A device, as claimed in Claim 5, wherein said actuating member acts on switching means controlling said gas supply valve.

7. A device, as claimed in any one of Claims 1 to 6, wherein said gas supply valve is disposed within said gas reservoir.

8. A device, as claimed in any one of Claims 1 to 7, including over-ride means for acting on said gas supply valve, to open it, independently of provision of said signal.

9. A device, for automatically opening a gas supply valve when the device reaches a predetermined depth in a fluid, substantially as described herein with reference to the figures of the accompanying drawings.

10. Underwater buoyancy apparatus comprising: (a) a device as claimed in any one of Claims 1 to 9, (b) a buoyancy chamber connected to receive, from said gas supply valve, gas to increase the buoyancy of the apparatus.

11. Underwater buoyancy apparatus, as claimed in Claim 10, substantially as described herein.