GB2500878A

GB2500878A - A vent valve for a buoyancy control means opened by manual or powered means

Info

Publication number: GB2500878A
Application number: GB1205424.3A
Authority: GB
Inventors: David Bonzon; Andrew Sinclair; Christophe Glez; Christopher Webb
Original assignee: PANDORA UNDERWATER EQUIPMENT SA
Current assignee: PANDORA UNDERWATER EQUIPMENT SA
Priority date: 2012-03-28
Filing date: 2012-03-28
Publication date: 2013-10-09
Also published as: GB201205424D0

Abstract

A vent valve for a buoyancy control device suitable for free-swimming divers, where the valve is opened both manually and by a powered means, such as from a hydraulic or pneumatic pressure line 25, the hydraulic or pneumatic pressure is equalised with the ambient pressure when not activated. The manual opening means comprises a manual pull dump 33 and 35 that is arranged such that it is not resisted by a piston 27 of the powered means. Water ingress into a bladder 1 of the buoyancy control device is restricted by a one-way valve 31 within the vent valve. The vent valve forms part of a venting system (Fig 2) for the buoyancy control device that comprises at least three vent valves which are opened simultaneously on operation of the powered opening means.

Description

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TITLE OF INVENTION

:Eflt Valve for Diver's Buoyancy Compensator.

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Technical Field

The present invention relates to a vent valve for use on a diver's buoyancy Jacket, that is either manually operated or auimatically operated thai operate as a étof at least three valves operating simultaneously.

Backciround of the Invention Diver's commonly use a Buoyancy Compensation Device (BCD) to compensate for the changes in buoyancy that occur during dive, such as from the compression of the neoprene in a diver's environmental protection suit, or from the * .:90fl mptio of gas in a dive cylinder. A means to add gas to a bladder in the BCD eiiabIes the qyrs buoyancy to be increased, and vent valves allow gas to be discharged and hence reduce the diver's buoyancy by reduction of the water 1 5 volume displaced by the bladder.

:::, If a vo!qrne of gas is in a bladder underwater, then the gas will not flow out of 5 vent in the bladder unless the vent is higher than the gas: gas does not flow from a low prSsure to a high pressure region on its own. This means that a minimum of three valves are required to guarantee that gas can be vented in any * 20 orientation of the diver. . -* * * * 4* -. - The drwback of having three or more vent valves is that in the event of an hesirabIe inprease in buoyancy, the diver may have to t each valve in turn in r* -orct to identify which one releases gas. Not all the valves may be easily !!aphable.

*... 25 It is desirable to have a method to open all the vent valves simultaneously. *.**

It is obvious that if more than one-vent valves is open-at once, then one- -w3' Valves have to be fined to prevent water ingress. -

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-jIç_- H.. -- -In water the ambient pressure will tend to collapse a bladder such that even if the gas is at the same ambient pressure as the vent, it may not flow to the vent Uñlesstherels an open gas path from the region containing the gas to.the vent.

Such gas paths may be kept open within a bladder by fitting a. spiral or spring inside the bladder The advantage of having multiple paths to vent valves open is ::...c7tltaimay;bè:dumped more rapidly. . H: The vent valves in common use on BCDs have a pull cord attached to a stopper, which allows for manual control of the valve.

The prior art includes various devices that link together multiple pull-cords.

10..H. US 6,217,257 describes a diver's buoyancy device with multiple vent valves Tht bre confrolied pneumatically, with one-way valves to prevent water ingress.

US 6,217,257 describes the control means to actuate the valve as being a ush-buttoñ hibh provides a pressurised gas supply to a piston that lifts the valve. It does not describe how the pressure is released: thepatent appears to provide no meané to release the pressure That is, operating the button described H. . :11.11 the patent would pressunse the pneumatic line to the vent valve, which in turn woUd cause*.thé valves to lift but there is no means to release the gas pressure in thE line desbribed, so the valve would remain lifted and the buoyancy bladder Another limitation of the prior art such as in the form of a vent valve in Us 6,211 7,257' is tI?at the addition of a pull-cord is not feasible tp The form described béèause the cord would normally feed through the device for which a gas tight connection is required for the device in Fig. 2 of US 6,217,257 to operate. * .

Yet aqother limitation of the prior art, such as US 6,?17,257, is that a loss of . 25..primatip p wer.would result in the valve becoming inoperable.

i.n.L4it Yet another limitation of the prior art, such as US 6,217257, is that it is not pSsible to open the valve manually because if the pneumatic supply is shut then **fl tbmove the valve would involve pulling a partial vacuum manually.

The activation of pneumatic valves underwater invariably involves power from a gas cylinder, as the use of a flexible gas volume would operatethe vents as

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the volume comes under increasing ambient pressure as the diver's depth increases; :.

-Obiect of the present invention It is an objective of the present invention to provide a pneumatic or hydriulic power to a BOO vent valve such that a loss of power causes. the valve to fail in a safe state, It is a further objective of the present invention to enable all the vent valves oñ a BCD to be opened or closed with a single action.

It is a further objective of the present invention to provide a vent valve 10.sUable for uSby an automatic buoyancy compensation device.

it is a further objective of the present invention to provide manual control of the:valvesiñ'thè event of loss of pneumatic or hydraulic power.

BRIEF SUMMARY OF THE INVENTION

The pSent invention provides a pneumatically controfled vent valve that 15. hasa manual over-ride active at all times to enable the valve to be opened, by the attachment o a pull-cord to a stopper or plug in the valve The present invention provides a fail-sale means to operate the valve using or I'

BRIEF DESCRIPTION OF THE DRAWINGS *

For q better understanding of the present inventipn and the advantages thereof and to show how the same may be carried into effect, reference wiH now be made, b' way of example, without loss of generality to the accompanying drawings in vich: I *:: H!9yre 1 shows, a pneumatically activated vent valve according to the present 25.ir'.ention which provides a consistent operating force and seating of the valve.

Fig: 2 shows an example embodiment of an hydraulic.drive providing fail-safe features. j:.. . . .

DETAILED DESCRIPTION OF THE INVENTION

: The invention will now be described in detail by reference to the aforementioned figures and by use of example embodiments. Reference is made to a BCD bladder It is not important the form of the bladder the present invention many be applied to many different types of bladder The sole special requirement :.:o::jhe blàddef tbbe used with the present invention is that the vent alves shall I arranged such that in any orientation of the bladder there is an open gas path from the gas in the bladder to one of the vents: at least three vent valves are required to fulfil this requirement.

The vent valves in an example embodiment shown in Fig. 1 have a * 1cónventionalmanual pull dump (33) in addition to a pneumatically or hydraulically powered piston (27). The pull dump may be on a cord (35)or a lever.

A hose () carries the gas from the inflator to the actuators is preferably is a narow.borehose. Kynar hoses are available with a 0.8mm bore and an outer diameter of 3.6mm, which have the effect of limiting thernaximum flow rate when * .. used with typical. BCD gas supply pressures to around 20 litres of gas flow per minute, and have a burst pressure exceeding the gas supply cylinder high pressure, such that if the first stage cylinder pressure regulator were to fail, then tetpse(7)Lwcu.lq not rupture, and therefore there is no risk of the bladder in the 20: BCD being inflated suddenly. Moreover, use of a very small bore hose means that should the hose break, the flow rate into the bladder is much lower than the fl minimum vent rate if the diver uses the manual vent controls on the vent valves.

* Ft;..' ., The supply hose (7) to the gas valves and is preferably flow limited by its * * bore, and the vent valves such as shown in Fig. I incorporate springs (37) and 25 optiqnally (38) that close the valve when it is not powered. It is possible but not * ... ...jtF.. . preferable to add a further flow restriction by use of an orifice or choice of small

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withid tFe connectors to the gas hose (7) or gas routing manifold. *.fl

:::: . Vent valves (2) with the features shown in Figure 1 namely an input gas hose (25), pçessure in which causes a piston (27) to move and open a plug or 30.stppper(29),ailowing gas in the bladder to escape through a one-way valve (31).

pu!l-dump (33) is preserved in the preferred embodiment, allowing mátual operation of the vent by the diver at any time. The pull-dump cords (35)

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maybe singülar'or may be combined: a minimum of three o f the vent valves (2) must be filled to the bladder in positions such that there is an open gas path between the retained gas in the bladder and at least one vent valve when the bladder is immersed in water A novel feature of the vent valves in the preferred embodiment lithe use of a wave spring (37) to apply even pressure to the plug (29 such, that;eats evenly. Retainers (39) prevent ihespring (37) from being displaced laterally.

The use of the wave spring avoids the valve leaking if it is operated mahually with a motion that in a conventional vent valve would tend to cause the plug (29) to take up an angle instead of remaining level with respect to the valve seat (30). A wave spring is a type of compression spring built from a series of thin wahers tht have a wave-like profile. Compressing the washers, which are

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.norrnalIy welded together, results in a reactive force that is even around the Oircurnference of the spring. A wave spring can also provide a greater extension fora particular spring force and spring bound size than a conventional wire compression spring, which can be advantageous in this application. :

Akeyfeature of the vent valve is that the plug (29) is not firmly attached to the iston (27), such that pulling the plug (29) via the cord (35) causes the plug (29)to lift off the seat (31) without the piston (27) having to move The seat at the tpof the pistqn (27) need not be attached to the plug (29)., The pneumatic power may be provided by an arrangement of gas valves that apply a lower gas pressure, such as 9 bar, to the hose (7) to activate the, valve, but wt1iqj1 in the..quiescent or inactive state opens the gas!ine, to the SOD bladder.

Whqri gs tIose (7) is a small bore hose then the volume of the gas vented to the bladder may be kept to a negligible amount.

An alternative, to the pneumatic power to activate the vent valve is shown in Fig. 2, namely a, hydaulic power source. In this case a bellows (50) contains a liquid such 4%4aqohol or water or silicone oil, and pressure on the bellows by the user causes presure to bui!d up in the hose (7) and the valve to be opened. The spring bias to th,p bellows causes the liquid to puli back the piston, when the pressure is removed. The pressure may be through a lever or directly on the bellows. 4..

I. . . The bellows:(50) or the hose (7) have a means through which gas can be drained and fluid topped up, but such means may be in the formtf a nipple or filling point: there is no heed for a hydraulic reservoir. During the tilling process,. sufficient provision should be made for the thermal expansion of the hydraulic liquid this can be accommodated by a partial fill such that expansion of the liquid extends the belióws.(50and contraction causes them to shrink in.size, but leaving sufficient movement for the manual action.

The bellows (50) may implemented in a variety of forms, including a thick walled * balloon such as a silicone moulding, alit may be a telescoping moulding, or it may 10. bé a series of telescoping elements with 0-ring seals.This invention is not limited to the specific embodiments disclosed herein which is intended to be illustrative and it covers all moditications and alternatives coming within the scope and spirit of the invention as defined in the attached claims.

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Claims

WE CLAIM1. A device comprising a valve for venting gas from a bladder that is opened by pressure in a pneumatic or hydraulic hose connecting to at least three vent valves which are opened simultaneously by that pressure and when open vent gas from the bladder, and further comprising a manual means for opening the valve, such that pulling on a manual pull dump is not resisted by the piston that provides the pneumatic or hydraulic motion, and in which water ingress into the bladder is restricted by use of a one-way valve in series with the vented gas flow.
2. A device according to claim 1 wherein the said vent valves are configured to be opened by a pneumatic pressure and configured to be closed by a counterforce created by or assisted by a wave spring in addition to a pull-cord enabling the valve to be opened manually.
3. A device according to claim 1 further comprising gas valves arranged such that a loss of electrical or gas power causes the valves to fail in a safe state in which the valve is closed and the manual action of the valve remains operable.
4. A device according to claim 1 incorporating a safety means to shut down the automatic buoyancy control system without affecting the ability of the diver to perform buoyancy control manually.BAmended claims have been filed as folIows-WE CLAIM1. A venting system for a bladder of a buoyancy control device comprising at least three vent valves that are simultaneously openable by pneumatically or hydraulically powered means to vent gas from the bladder during use wherein each vent valve is opened by a pneumatically or hydraulically powered piston or by means of a manual pull dump, the pull dump being arranged such that its movement is not resisted by the piston of the powered means and wherein water ingress into the bladder is restricted during use by means of a one-way valve within the vent valve.2. The venting system for a bladder of a buoyancy control device as claimed in claim 1 wherein each vent valve can be opened by means of pneumatic pressure acting on the powered piston or by means of a pull-cord of the manual pull dump, against a closing force created by, or assisted by a wave spring.0 3. The venting system for a bladder of a buoyancy control device as claimed LI') in claim 2 wherein in the event of the loss of said pneumatic pressure the r.. ..vent valve is biased into a closed position by the action of the wave spring, but remains openable by means of the manual pull dump.