GB2499410A

GB2499410A - A valve system for use in testing in situ gas detectors

Info

Publication number: GB2499410A
Application number: GB1202562.3A
Authority: GB
Inventors: John Michael Stones
Original assignee: GAS SAFE EUROP Ltd
Current assignee: GAS SAFE EUROP Ltd
Priority date: 2012-02-14
Filing date: 2012-02-14
Publication date: 2013-08-21
Anticipated expiration: 2032-02-14
Also published as: GB2499410B; GB201202562D0

Abstract

The valve system is used in transferring a reference gas from an aerosal container to a flexible enclosure temporarily installed around a gas detector to be tested, such as a carbon monoxide detector. The valve system comprises a first component 1 is a cap with a central orifice 4 that fits over a standard aerosal valve, the cap may have raised portions 8 thereon to penetrate a flexible enclosure such as the bag installed around the detector. A second component 2 is an annulus that locks onto the upper surface of the cap and in use the first and second components trap the flexible enclosure or bag and puncture it.

Description

AN IMPROVED VALVE SYSTEM FOR EXTERNAL ENCLOSURE TYPE IN- SITU

GAS DETECTOR TESTERS

The present invention is in the area of improvements to the valve system for use in the external enclosure type of test devices for testing gas detectors in-location. The sensitivity of sensors used in gas, e.g. carbon dioxide (CO), detectors is subject to a number of sensor ageing processes and battery, where employed, failure. As a consequence, it is normal practice to test the efficient working of such gas detectors at regular intervals. Testing devices have been disclosed in the literature (Elliott GB2269669, Hoppenworth US2004050137) for testing uninstalled and therefore mobile detectors suitable for placement in a test chamber and others (Scheffler W02008051732, Noel & Sourdeix FR2715223) interface only with specific detector designs. Those that have been proposed to facilitate the testing of installed and nonspecific detector designs (Deutsch & Wantz US 5959188, Chan & Hung CA2310733, Stones GB2371860, Stones GB 2345340) involve the, temporary, creation of a gas-tight enclosure about the detector into which a reference concentration of the gas to be detected is injected or otherwise generated.

Deficiencies of current practice

Whereas the prior art devices based on the creation of a temporary gas-tight enclosure about the detector to be tested overcome some of the problems involved in the testing of installed gas detectors of different shapes, they are difficult (fiddly) to use in a multiple use situation, frequently fail to create a gas-tight passage between the test gas aerosol container and the enclosure and will tend to damage the flexible enclosure wall in multiple use.

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Brief description of the invention

The present invention is a two component valve assembly the components of which are placed on either side, of the wall of a flexibly walled enclosure such as that disclosed in GB2345340. A first component, which is placed on the outside of the enclosure, takes the form of a cap with raised wings emerging from its outer perimeter and a raised annulus surrounding an orifice at the cap centre which possesses protuberances around its upper surface. The orifice continues down below the cap surface as a cylinder which fits over the valve of a standard aerosol valve system which may then be activated by pressing down on the raised wings.

The second component of the invention takes the form of annulus which fits, from the inside of the enclosure, over the raised annulus on the surface of the first component and locks with it to securely trap the enclosure wall and cause it to be penetrated by the protuberances on the first component to form a gas tight portal.

Once the enclosure is installed about the device to be tested and encloses it, an aerosol canister of test gas is inserted into the first component cylinder which is now contiguous with the enclosure and may be activated to fill the enclosure with the appropriate level of test gas.

The second component of the valve assembly (the "retainer") is brought together with the first component from the other (inside) side of the enclosure wall and pressed into a circular trough, formed by a raise annulus surrounding a central gas passageway leading back to the aerosol valve and a pair of raised wings emerging symmetrically from the perimeter of the first component. The raised annulus surrounding the central gas passageway is topped with a plurality of protuberances mounted vertically around its upper surface which penetrate the flexible wall as it is stretched over them. Once the two components are locked together and the enclosure wall is penetrated, the first

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component is mounted on a conventional aerosol containing a test gas which is injected into the enclosure in a known quantity (time controlled).

Once the test is complete the aerosol container is removed from the valve assembly which is retained in place as a portal in the flexible enclosure which is moved to the next device to be tested whereupon the aerosol is replaced and the procedure repeated. The present invention involves attachment of the valve system only once in the working life of a flexible enclosure, extend the working life of the flexible enclosure, enables simple and rapid attachment, and detachment, of a standard aerosol container containing the appropriate test gas and safe transfer of the test gas to the enclosure and transfer of the enclosure from device to device. Thus the invention overcomes all the difficulties in use of prior art devices.

Detailed description of the invention

The invention will now be described in detail with reference to drawings 1,2 and 3

Drawing 1 shows both the first (1) and second (2) components of the improved valve system in such a manner as to indicate the design features which allow them to lock securely together. The first component (1) takes the form of a cap (3) with an internal radius of from 18 mm to 28 mm, preferably 20 mm to 26 mm and most preferably 22 mm to 24 mm and with a central circular orifice (4) which is up to 2 mm in diameter, preferably from 0.5 mm to 1.5 mm in diameter. The top surface of the cap (5) provides a platform for the second component (2) and is flanked by two raised wing-like structures (6) from 8 mm to 16 mm, preferably from 9 mm to 14 mm and most preferably from 11 mm to 12 mm wide and from 1.5 mm to 2.5 mm thick, mounted on the perimeter of the cap directly opposite each other and extending away from the cap by from 13 mm to 22 mm, preferably 15 mm to 20 mm and most preferably from 17

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mm tol8 mm. A raised annulus (7) surrounding the central orifice (4) and topped with a plurality of protuberances (8) standing vertically at least 8 mm high above the top surface of the cap platform (5), evenly spaced around the top of the annulus, acts as a guide to docking the second component (2) on the platform (5) of the first component over the raised annulus and enables the protuberances (8) to penetrate any flexible film trapped between the first and second components of the invention. When the two components are brought together on either side of a flexible enclosure wall and the second component is locked into position by slightly oversized and overhung ledges (9) on the upper external perimeter of the annulus and expanding clips (11) on the second component which interlock with a docking port (10) in the cap surface at the base of the annulus.

Drawing 2 shows the underside of the valve assembly, with both components brought together, and shows the cylindrical wall (12) that surrounds the underside of the central orifice. The internal diameter of the cylindrical wall is such as to fit over the valve of an appropriate aerosol container. Drawing 2 also shows the plurality of spacers (13) spaced around the inside if the cap which strengthen the cap but whose primary purpose is to guide the end of the cylindrical wall to dock securely with the aerosol container valve.

Drawing 3 shows a top view of both components engaged with each other and additionally shows the optional non-return valve (14) embedded within the central orifice (4).

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General considerations

The design of the invention is such that it is compatible with standard aerosol valves and can be used as a replacement for the conventional activator trigger. It can be fabricated by any means but preferably injection moulding using any conventional polymeric material and particularly high density polyethylene or polypropylene. Method of Use

In a first embodiment, as a gas detector testing device, the operator places the second component (2) inside the flexible walled enclosure and places the enclosure around the detector to be tested. Once the detector is isolated the first component (1) is brought against the flexible enclosure wall and pressed against the second component such as it fits over the annulus (7) onto platform (5) until it is locked into position and the protuberances (8) have pierced the enclosure wall. The valve of an aerosol is then inserted into cylinder (12) and a timed quantity of test gas is released into the enclosure by pressing down on the wing-like structures (6) and the aerosol may be removed. Following completion of the test the flexible enclosure is removed from the tested detector and placed around the next detector for test with the valve system still in place. It will be noted that the improved valve system is suitable for multi-use. However, in another embodiment a new valve system would be sold, together with a new flexible enclosure with each aerosol of test gas.

In yet another embodiment the valve system is sold already attached to the flexible walled enclosure.

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AN IMPROVED VALVE SYSTEM FOR EXTERNAL ENCLOSURE TYPE IN- SITU

GAS DETECTOR TESTERS

What we claim is:-CLAIM1

A multi-component valve system to improve the ease of transferring a test gas from an aerosol container to a flexible enclosure temporally installed around a gas detector to be tested and subsequently removing the enclosure from the tested device for multiple device testing purposes, comprises two interacting components :

a) a first, actuator, component in the form, substantially, of a cap with central orifice adapted to fit over, interact with, and control a standard aerosol container valve, retain a second component of the valve system on its upper surface and penetrate the wall of a flexible enclosure presented to it;

b) a second, retainer, component, in the form, substantially, of an annulus which fits and locks firmly onto the upper surface to trap the wall of a flexible enclosure wall between the two components.

Claims

CLAIM 2

A first, actuator, component of the multi-component valve system as claimed in claim 1 wherein it takes the form, substantially, of a cap possessing a central orifice above a cylindrical structure passing down below the upper surface of the cap adapted to fit over a standard aerosol container valve, surrounded on the upper surface by a raised annulus possessing a plurality of protuberances rising from its upper surface, which is also surrounded by raised wing like protuberances emerging, diametrically opposite each other, from the cap perimeter wall forming a trough on the cap upper surface between the annulus surrounding the central orifice and the raised wing like protuberances around the cap perimeter.

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CLAIM 3

A second, retainer, component of the malti-component valve system as claimed in claim 1 which takes the form, substantially, of an annulus which fits securely within the trough formed between the raised wing like protuberances and the annulus surrounding the central orifice on the upper surface of the first, actuator, component to effectively trap the wall of a flexible enclosure that is placed between the two components and cause the protuberances on the central annulus of the first, actuator, component to penetrate the wall.

CLAIM 4

A first component of the multi-component valve system as claiml and claim 2 wherein the cylindrical structure is a continuation of the central orifice, fits over the valve of a test gas aerosol container and activates test gas release through the central orifice when downward pressure is applied to the wing like protuberances of the first component. CLAIM 5

A first component of the multi-component valve system as claimed in claims 1,2 and 4 wherein the annulus surrounding the central orifice possesses a plurality of ledges overhanging its outer perimeter on the upper surface which close over the second component when it is pressed down onto the first component.

CLAIM 6

A first component of the multi-component valve system as claimed in claims 1,2,4 and 5 wherein the annulus surrounding the central orifice has a non-return valve built in. CLAIM 7

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A first component of the multi-component valve system as claimed in claims 1,2,4, 5 and 6 wherein the plurality of protuberances rising from the central annulus are drawn to a point or to an alternative cutting edge.

CLAIM 8

A second component of the multi-component valve system as claimed in claims 1 and 3 wherein locking anchors on either side of the inner annulus wall slot into docking sites in the trough of the first component.

CLAIM 9

A multi-component valve system to improve the ease of transferring a test gas from an aerosol container to a flexible enclosure temporally installed around a gas detector to be tested and subsequently removing the enclosure from the tested device as claimed herein with reference to drawings 1 to 3.