GB2393770A

GB2393770A - End fitting

Info

Publication number: GB2393770A
Application number: GB0401066A
Authority: GB
Inventors: John V Bowden
Original assignee: GLENSON
Current assignee: GLENSON
Priority date: 2004-01-17
Filing date: 2004-01-17
Publication date: 2004-04-07
Anticipated expiration: 2024-01-17
Also published as: GB2419929A; GB0401066D0; GB2393770B; GB0600225D0; GB2419929B

Abstract

An end fitting for a gas hose 23, for releasably connecting an appliance to gas supply pipework. In use, the end fitting connects to a valve (17) of the gas supply pipework, a projection 25; 29; 32 of the end fitting forcing a valve member 21 off its seat 20 in order to allow gas to flow from a gas supply into the hose and thence into the appliance. The end fitting is releasably connectible to the valve 17 by way of a bayonet fitting. At least a part of the bayonet fining or the projection of the end fitting is of a material having a lower melting point than the remainder of the end fitting. Melting of this part, for example in the event of fire, results in the valve member 21 returning to its seat 20, thus causing the valve 21 to close automatically.

Description

- 1 - End Fitting This invention relates to an end fitting, particularly,

but not exclusively, for a gas hose.

Commonly, in use, such a gas hose extends from a domestic gas appliance, such as a cooker, with its end remote from the cooker having said end fitting and being engaged with an element of the gas supply pipework as a bayonet fitting. The end fitting can be formed as one of an interengaging plug and socket connection, with an element of the gas supply pipework being formed as the other thereof.

Such element of the gas supply pipework is normally a valve which is spring loaded onto a seat to prevent outflow of gas from the gas supply pipework. The end fitting normally has a metal projection which when the hose is engaged with the gas supply pipework forces the valve off its seat, in order to allow gas to flow from the gas supply into the hose, and then to the gas appliance.

A rlicadvantae with this arrangement is that in the event of a fire although a hose may be damaged along its length, its metal end fitting, including the valve actuating projection, is likely to remain undamaged.

There is thus the danger that such a damaged hose may continue to be used or be reused as the bayonet fitting, in use, of the hose to the gas supply pipework remains unaffected and will allow gas to flow to the damaged hose from which it may escape.

- 2 - An object of the invention is to provide an end fitting to obviate this disadvantage. According to a first aspect of the invention there is provided an end fitting, one end of which is connectible to a hose, the other end being releasably connectible to a valve, said end fitting having a part formed from a material having a lower melting point than the remainder of the end fitting, such that in use, when the end fitting is connected to the valve and the part is in an unmelted state, the valve is maintained in an open position such that fluid is able to flow through said valve and into said hose, and such that melting of the part causes the valve to close.

Preferably said end fitting is releasably connectible to a valve by way of a plug and socket bayonet connection. Advantageously, the remainder of said end fitting is formed from a heat resistant material, desirably of metal, and preferably of brass. Preferably, said part is formed from plastics material, and advantageously said part is formed from a low melting point plastics material such as Acetal C. Preferably, said end fitting has a member which, when said part is unmelted and said end fitting is connected to said valve, pushes a valve member out of a valve seat, thus opening said valve.

Preferably, said part comprises at least a portion of said member, and conveniently said part is an insert in the form of a cylindrical disc having an inner and an outer trace, and having a cylindrical tip projecting from said

- 3 - outer face, said tip constituting said member. Advantageously, said disc has at least one aperture extending therethrough.

Alternatively, said part forms part of said bayonet connection, and melting of said part causes said end fitting to disengage tram said valve, thus causing said valve to close. Conveniently, said part forms an at least one projection of said bayonet fitting. Preferably, said member comprises a spigot, and advantageously said spigot is hollow.

According to a second aspect of the invention, there is provided a hose having at one of its ends an end fitting of said first aspect of the invention.

According to a third aspect of the invention, there is provided a bayonet connection comprising a first member having a valve member normally biased onto a valve seat to prevent flow through the first member, and a second member having an element forcing said valve member off its seat to allow flow through said first and second members, with the part of said second member forming said bayonet connection or said element being of a material which will melt, in use, at a temperature lower than the melting point of the remainder of the second memher such melting resulting in a closing of said valve.

According to a fourth aspect of the invention, there is provided an end fitting for a hose adapted to be connected, in use, to an element of fluid flow pipework including a valve, thereby to allow fluid flow through the hose, the end fitting comprising a part adapted to effect said connection, and a member adapted to open said valve when said connection is effected, in use, said part

( or said member being of a material which will melt, in use, at a temperature lower than the melting point of the remainder of the end fitting, such melting resulting in a closing of said valve.

The invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a side view of an end fitting of a prior art gas hose,

Figure 2 is an end view of the end fitting of Figure 1, Figures 3 and 4 are respectively an end view and a fragmentary part-

sectional side view of part of a first embodiment of an end fitting of the invention, Figures 5 and 6 are views equivalent to Figures 3 and 4, for a second embodiment of the invention, Figures 7 and 8 are views equivalent to Figures 3 and 4, and 5 and 6, for a third embodiment of the invention, and Figures 9 to 1 I respectively are views showing a hose having the first embodiment of end fitting of the invention firstly connected to an element of fluid flow pipework with a valve thereof held open, secondly with the connection undone and the valve closed, and thirdly with the hose separated from the pipework.

As stated above, the invention relates to an end fitting, particularly, but not exclusively for a gas hose. Thus although the following description

and the drawings relate specifically to a gas hose incorporating an end fitting in accordance with the invention it will be understood that such an end fitting could be used with other tubes, pipes, conduits and the like.

Figures 1 and 2 show a conventional form of end fitting for a gas hose. This comprises a cylindrical body part 10 of brass or other metal, which has at its rear end, not shown, an integral brass collar, into a rearward end of which is secured a gas hose of conventional form. The body 10 is hollow and at its forward, closed end 11, is formed with four circular openings 12 which are arranged equi-angularly around the central axis of the cylindrical body part 10 to allow flow of gas into the hose as will be described hereinafter. At the centre of the closed end 11 is an engagement element in the form of a forwardly projecting cylindrical tip 13, also of brass or other metal.

This end fitting of the gas hose constitutes a plug of a well-known plug and socket bayonet connection. To this end the body part 10 carries thereon in a freely rotatable manner, the female part of the bayonet connection in the form of a cylindrical flange 14 having an integral collar 15 in which is formed a pair of diametrically opposed L-shaped slots l 6.

This end fitting is intended to be engaged with and connected to an element of the gas supply pipework of the form shown in Figures 9 to l l. In these Figures such element, being the second part ol the bayonet fitting, namely that to which the gas hose is connected, is specifically a right-angled gas valve 17. This is of conventional form having a lower exteriorly threaded inlet 18 and a socket-like outlet 19 into which the body part to of the end fitting is received, in use. The base of the socket is formed as a valve seat 20 onto which is forced a valve member 21 under the action of a biasing spring 22. Thus when the valve member is held off its seat, as shown

- 6 in Figure 9, gas can flow through the inlet, and the valve seat, into the end fitting and thus the hose 23. In the position shown in Figure 9, respective diametrically opposed projections on the interior of the socket part of the valve 17 are received in the respective closed ends of the L-shaped slots in the collar 15 of the female part of the bayonet connection carried on the body part 10 of the end fitting so, as to complete the connection in the normal manner. As can be seen from Figure 9, when the end fitting is received in the socket with the bayonet connection effected, the tip 13 engages the valve member 21 and forces it off its seat against its biasing spring 22. Thus gas can flow into the hose as described above. It will be noted that with this arrangement there is a space between the surface of the body part from which the tip 13 extends and the inner end surface of the socket in which the valve seat is formed.

In the event of a fire at or in the vicinity of this bayonet connection, there is no safety feature which will cut-off the gas supply to prevent the escape of gas from a damaged hose or an appliance to which it is connected.

Another disadvantage is that whilst the rubber components of the conventional gas hose may be damaged in such a fire, the end fitting, being of brass or other metal, i.e. a relatively high melting point material, may well be undamaged. with the consequence that the hose might be reused even though slime part of the rubber components along its length may be damaged.

The present invention seeks to provide the end fitting with such a safety feature so that not only is the gas supply cut-off in the event of a fire, but also that the hose cannot be re-used thereafter.

- 7 - In the first embodiment shown in Figures 3 and 4, the end fitting is of very similar form to the prior art end fitting shown in Figures I and 2 and the

same numerals will be used for like parts. It will be noted that in Figure 4 the flange 14 and collar 15 of the one part of the bayonet fitting are omitted for clarity. Accordingly it can be seen from Figures 3 and 4 that the end fitting is formed with a brass or other metal hollow cylindrical body part 10.

However in place of the closed end 11 with its integral tip 13, the open extremity of the end fitting is stepped outwardly to provide a cylindrical recess in which is secured a plastics material insert in the form of a cylindrical disc 24 from the centre of the outer Lace of which projects a cylindrical tip 25 of the same length and size as the tip 13 of the prior art end

fitting. The insert can be secured in place by any suitable means, such as adhesive, or by crimping over the extremity ol the body at the outwardly directed front face of the disc 24. As can be seen in Figure 3, the disc has four openings 26 therethrough in the same manner as all the openings 12 of the prior art end fitting to allow gas flow through the insert into the hose to

which the end fitting of Figures 3 and 4 is fitted.

Figures 9 to 11, referred to above in connection with the end fitting of Figures 1 and 2. are equally applicable to describe the use of a hose 23 having the end fitting of Figures 3 and 4 connected thereto, with the body part 10 shown in Figures 3 and 4 having the flange 14 and collar 15 of one part of the bayonet fitting secured thereon against axial movement in the known manner. Accordingly in the position shown in Figure 9, with the bayonet connection between the hose and the gas valve 17 effected the body part 10 is received in the socket-like outlet 19 so that its tip 25 has sufficient length to push the valve member 21 off its valve seat 20, against the force of

- 8 - its biasing spring 22, so that gas supplied to the inlet 18 will pass around the valve member 21, and through the openings 26 into the body part 10 and thus to the hose 23.

If the bayonet connection between the hose and the gas valve is released, by applying slight inward pressure on the hose whilst at the same time twisting the flange 14 in the required direction, the hose will subsequently be forced towards its Figure 10 position by the biasing force acting on the valve member, which itself will push on the tip 25, so that the end fitting will move towards the position shown in Figure 10 with the valve now closed. Figure 11 shows the position where the hose is completely removed from the socket of the gas valve.

Whilst Figures 9 to> 11 show normal use of the end fitting, this being identical with the use of the known end fitting shown in Figures 1 and 2, the situation in the event of a fire would be different. Accordingly if a fire were to break out with the bayonet fitting in place, i.e. as in Figure 9, with the gas valve member 21 held open, the temperature would start to rise and would continue to do so until the melting point of the material of the tip 25 was reached. As mentioned above, the tip is of plastics material, this being a low melting point material, particularly as compared to that of the body 10 of the end fitting, in fact, the whole of the end fitting with the exception of the disc 24 and its integral tip 25. Accordingly when the temperature reaches the melting point of the plastics material, the disc 24 and tip 25 will melt, and, in particular' the melting of the tip removes the force holding the valve member 21 Open which is thus returned by its spring onto its valve seat thereby to shut off the supply of gas to the hose. In this regard it will be noted that all

- 9 - of the relevant components of the gas valve would be of a relatively high melting point material, again such as brass or other metal. As mentioned above, the bayonet fitting in its normal way, provides a gap between the inner end of the socket and the outer face of the disc 24. and this can form a space to receive the melted material of the tip 25. Alternatively the melted material of the tip 25 and disc 24 may flow into and be received in the hollow interior of the body part 10.

In any event the melting of the tip results in a closing of the valve, so that the end fitting provides a set ety feature which cuts off the gas supply when the melting point of the material from which the insert is formed is reached. The hose can then be separated and removed from the gas valve 17 as shown in Figures 10 and 11 in the normal manner. It will be understood that not only does the safety feature of the end fitting provide an automatic cut-off of the gas supply in the event of a fire. but it also ensures that the hose cannot be re-used, in that it no longer has means for opening the valve of the element of the gas supply pipework if it were to be re-engaged by way of its bayonet fitting to the position shown in Figure 9, given that its tip 25 has melted and is no longer present to apply the force to move the valve member off its seat. Thus there is no danger of damaged hoses being reused.

The invention thus provides the above mentioned safety feature in a convenient, effective and low cost manner, it merely being necessary to arrange for the end of the conventional body part to to be provided with a plastics material or other low melting point material insert.

- 10 The second embodiment of the invention shown in Figures 5 and 6 is very similar to that of the first embodiment and merely has a different shape of' insert. As shown in Figure 6, the insert has a longer but smaller diameter part 27 within the body 10 and, extending from the front face thereof, a frustoconical portion 28 from which extends a central cylindrical tip 29, which is shorter than the tip 25. Openings 30, equivalent to the openings 26 of the first embodiment, extend through the portion 28 and the part 27.

Again the insert will be of a low melting point material as compared to the material of the remainder of the end fitting and also the relevant components of the gas valve 17, so that in the event of a fire the tip 99 which forces the valve member 21 off its seat to allow flow of gas through the openings 30 and into the hose, will, together with the part 27 and portion 28, melt in the same manner as described above so that the force holding the valve member open will be released and the valve will close. Once again, therefore, the end fitting provides a safety feature which acts to automatically cut off the gas supply from the gas valve 17 in the event of a fire, and additionally, as described above, the hose cannot be reused after the insert has melted, thereby preventing possible reuse of a hose of which its rubber components are damaged.

Whereas with the first and second embodiments the safety feature has been incorporated in the plug of the bayonet fitting, the embodiment shown in Figures 7 and 8 has the safety feature in the socket part of the bayonet fitting. Accordingly here the gas valve would have a plug in the form of an annular collar replacing the socket-like outlet 19 of the gas valve 17 of the first and second embodiments, with this plug having in its exterior surface a

pair of diametrically opposed L-shaped slots, so that the plug forms one part of the bayonet fitting. The end fitting shown in Figures 7 and 8 forms the other part of the bayonet fitting, being in the form of a socket formed by a hollow housing 31 of brass or other high melting point material. As shown in Figure 8, a cylindrical hollow valve actuating spigot 32 extends through the base of the socket and has its outer end flush with the outer end of the socket. The diameter of the spigot is such that there is an annular space between its exterior surface and the interior surface of the hollow housing 31 and, in use, the collar of the plug of the gas valve fits into this annular space, with its interior surface sealing with the exterior surface of the spigot 32 by way of a sealing ring 33 shown in Figure 8. A retaining ring 34 is fitted on the spigot 32 within the housing to retain the connection between the spigot and the housing.

As shown in Figures 7 and 8. the diametrically opposed projections which are received in the respective L-shaped slots in the plug of the gas valve part are in the form of pins 35 fitted in the housing 31 and extending into the interior thereof as cylindrical heads 36 of a size to be received in said L-shaped slots and complete the bayonet fitting when the socket of Figures 7 and is pushed onto the collar of the gas valve and twisted in the normal manner. When this connection takes place, it will be understood that the forward end of the spigot 32 comes into engagement with the valve member of the gas valve and forces it off its seat thereby opening the valve and allowing gas to flow from the gas supply pipework, through the gas valve and into the hollow spigot 32, from which gas is supplied to the hose having

- 12 the housing 31 as its end fitting. Each of the pins 35 with their respective heads 36 are made of plastics material, namely material having a relatively low melting point, particularly in relation to the remainder of the housing 31 and spigot 32 which again will preferably he of brass or other metal. as would the relevant components of the gas valve. It will be appreciated that, however, only the heads 36 need be of low melting point material, although it is preferable that the pins 35 in the respective openings in the housing 31 are also of low melting point material, i.e. that the pins and heads are integral.

Accordingly in use when the temperature rises to the melting point of the material of the heads 36, these will melt, and as a result the bayonet connection will no longer be in existence. Accordingly this allows the biasing force of the spring to return the valve member onto its seat. This movement of the valve member pushes the spigot 32 in a direction which moves the housing 31 off the collar of the gas valve, whereupon the hose can be removed from said gas valve. Again, therefore, the end fitting provides a safety feature to automatically cut-off the supply of gas in the event of a fire' and additionally the hose cannot be reused.

It is anticipated that the provision of only the three types of gas hoses described herein, i.e. fitted with the three types of end fittings respectively would he compatible with all quick-disconnect gas valves currently available and approved for use in the UK. Accordingly the safety feature would be provided without having to modify or replace the mating gas valve in any way, thereby clearly saving costs.

- 13 Although it is considered that many types of plastics or other materials would be suitable for use as the low melting point material, a copolymer such as Acetal C has been found to be the most suitable.

Claims

- 14 CLAIMS

1. An end fitting, one end of which is connectible to a hose, the other end being releasably connectible to a valve, said end fitting having a part formed from a material having a lower melting point than the remainder of the end fitting, such that in use, when the end fitting is connected to the valve and the part is in an unmelted state, the valve is maintained in an open position such that fluid is able to flow through said valve and into said hose, and such that melting of the part causes the valve to close.

2. An end fitting as claimed in Claim 1, wherein said end fitting is

releasably connectible to a valve by way of a plug and socket bayonet connection.

3. An end fitting as claimed in either of the preceding claims, wherein the remainder of said end fitting is formed from a heat resistant material.

4. An end fitting as claimed in Claim 3, wherein the remainder of said end fitting is formed from brass or other metal.

5. An end fitting as claimed in any of the preceding claims, wherein said part is formed from plastics material.

6. An end fitting as claimed in Claim 5, wherein said part is formed from a low melting point plastics material.

- 15

7. An end fitting as claimed in Claim 5, wherein said part is formed from Acetal C.

8. An end fitting as claimed in any of the preceding claims, having a member which, when said part is unmelted and said end fitting is connected to said valve, pushes a valve member off its valve seat, thus opening said valve.

9. An end fitting as claimed in Claim 8, wherein said part comprises at least a portion of said member.

10. An end fitting as claimed in Claim 9, wherein said part is in the form of a cylindrical disc having an inner and an outer face, and having a cylindrical tip projecting from said outer face, said tip constituting said member.

11. An end fitting as claimed in Claim 10, wherein said disc has at least one aperture extending therethrough.

12. An end fitting as claimed in any one of Claims 2 to 7, wherein said part forms a portion of said bayonet connection, and wherein melting of said part causes said end fitting to disengage from said valve, thus causing said valve to close.

13. An end fitting as claimed in Claim 12, wherein said part forms at least one engagement element or projection of said bayonet fitting.

( - 16

14. An end fitting as claimed in Claim 12, having a member which, when said part is unmelted and said end fitting is connected to said valve, pushes a valve member off its valve seat, thus opening said valve.

15. An end fitting as claimed in Claim 14, wherein said member . comprises a Spigot.

16. An end fitting as claimed in Claim 15, wherein said spigot is hollow.

17. A hose having at one of its ends an end fitting according to any one of Claims 1 to 16.

18. A bayonet connection comprising a first member having a valve member normally biased onto a valve seat to prevent flow through the first member, and a second member having an element forcing said valve member off its seat to allow flow through said first and second members, with the part of said second member forming said bayonet connection or said element being of a material which will melt, in use, at a temperature lower than the melting point of the remainder of the second member, such melting resulting in a closing of said valve.

( - 17 1 7

19. An end fitting for a hose adapted to be connected, in use, to fluid flow pipework including a valve, thereby to allow fluid flow through the hose, the end fitting comprising a part adapted to effect said connection, and a member adapted to> open said valve when said connection is effected, in use, said part or said member being of a material which will melts in use, at a temperature lower than the melting point of the remainder of the end fitting, such melting resulting in a closing of said valve.

20. An end fitting substantially as hereinbefore described, with reference to, and as shown in Figures 3 and 4, or Figures 5 and 6, or Figures 7 and 8 of the accompanying drawings.