GB2264767A - Gas taps - Google Patents

Abstract

A gas tap comprises a plug valve 16 to control gas flow in a first passage, fed with gas via a flame failure shut-off valve (not shown) in a second passage 10 which is at right angles to the first. A stem 18 in the first passage carries a cam 20 which is axially displaceable to hold the shut-off valve open until a flame is established in the usual way. An intermediate member is located between the cam 20 and a pan 14 of the shut-off valve, the intermediate member being in the form of a ring 22 held captive on the stem 18 by a clip 24. Once the ring 22 engages the wall 30 of the passage 10 it is forced towards the part 14 by further movement of the cam 20. The intermediate member may alternatively comprise a push member supported for movement axially of the passage 10 (Fig. 3) or a head formed on the part 14 (Fig. 4). <IMAGE>

Description

GAS TAPS This invention relates to gas taps of the kind comprising a plug or the like which is moved to vary a rate of flow of gas through the tap between at least an off condition and a maximum flow condition, and possibly to set a number of intermediate flow rates. One well known tap of this kind is provided with a flame failure device in the form of a check valve which is held close, or example by a spring until opened for example by an electromagnet, and the existence of a steady flame at a burner fed from the tap creates conditions which cause the electromagnet to be energised so as to open the check valve to maintain the gas supply.In such taps means are provided to hold the check valve open during an ignition sequence and until suc time as the steady flame is aclieved. Usually this corses a displaceable member associated with the plug or the like.

Hitherto the plug or the like and the check valve 1ave en axially arranged effectively in series in a common straight flow passage. In such arrangements, a stem can be axially displaced for example against a spring to hold the check valve open.

rnlese axially arranged devices require a certain miti;num axial dimension. In contemporary designs of gas appliances that dimension is not readily available. The industry solution is to locate the two valves effectively at right angles to one another. In short the axial passage is bent at right angles so that the magnetic check valve extends laterally of the passage in which the plug or lie is located. This introduces a need to make the physical connection between the axially displaced stem and the displaceable part of the check valve.One accepted solution is to use an intermediate member which conveniently is a ballbearing. The stem has a cam which displaces the ballbearing for lateral movement to open the magnetic valve.

rrtle object of the invention is to provide improvements.

According to the invention a gas tap comprises a plug or the like for controlling the rate of flow and located in a first passage, a flame failure device check valve located in a second passage extending generally transversely of the first, and an intermediate member located between the to valves and arranged so that axial displacement of a stem displaces the intermediate member laterally to open the check valve, and is characterised in that the intermediate member is physically connected to one or other of the parts.

tese neans, it is possible to dissemble the valve either from the plug or like end or from the magnetic valve end without risking loss of the intermediate member.

according to a presently preferred feature of the invention the intermediate member is a ring connected to one of the parts by a wire or like link, and this has the advantage that the gas flow may be about the ring and trou the ring.

Three embodiments of the invention are now described with reference to the accompanying diagrammatic drains wllereiz Figure 1 is a- fragmentary sectional elevation of a first arrangement Figure 2 is a section taken on the line XX of Figures 1 on an enlarged scale; figure 3 is a view similar to Figure 1 of a second embodiment; and Figure 4 is a view similar to Figure l of a third embodiment.

Turning first to Figures 1 and 2, the bod of the valve is arranged for flow of gas from a supply along lateral passage 10 and into a passage extending generally in the direction of the axis 12 to pass through an outlet (nowt shown) connected to a burner. Flow in the passage 10 is controlled by a flame failure device valve as previously mentioned, and which is opened by displacing member 14 in the direction of the arrow A in the figure.

The tapered plug 16 controls flow of gas to the outlet and may be associated with a control plate or uniting plate with predetermined angular positions for off, on, and possibly for different flow rates in the ON condition.

A. stem or spindle 1S is axially displaceable relative to the plug 16 and against spring pressure. The sten carries a caii 20. An intermediate member 22, in this enbodiment in the form of a bead or ring is arranged generally between the cain 20 and the stem 14. The ring is held in place, in this instance, by a wire clip 24 having, inturned end 26 engaged in the bore of the ring and a U shaped portion extending around the stem 18. The clip is held to the stem in assembly by a further ring 26 which may be a rubber or like grommet frictionally engaged with the stem 20.

It will lie appreciated by those skilled in the art that there is no loading on the spring clip or on the grommet which are simply serving to hold the ring in approximate position. I-Then the stem 18 is displaced axially in the direction of the arrow E f the ring is displaced with it, and encounters the surface 30 of the passage 10 preventing further axial displacement of the ring and the cam then forces it to travel in the direction of the arrow A to. displace the valve part 14.

Gas flows through the passage 10 about and possibly through the ring on its way to the plug and the outlet.

"hen the electromagnetic check valve is held open by the alternative means, the stem 18 can be released to be spring returned and the ring is then retracted to approximately the illustrated position.

The ring is part-spherical externally, so that if it turns oily about the stem for a limited angular extent it is still effective to operate the check valve, being held in aligniaent by the wall of the passage 10.

Figure 3 shows a second embodiment in which the intermediate member takes the form of a plug part 40 integral with a stem 42 which is to engage the end of the check valve 14. Cam 20 is illustrated in contact with the plug part 40. The part 40 42 is located in position by means of a starlock washer or other element 44 frictionally engaged with the stem 42 on the one side of an internal shoulder 46 in the bore l0 and an G-ring of rubber or like material 48 engaged in a groove on the plug 4Q on the opposite side of that internal shoulder.

The arrangement can be assembled in the illustrated position by extending the stern 42 through the shoulder and then engaging the part 44 or alternative a pre-- assembly can be made of the parts 40-44 and ZFG which can be then pushed through the shoulder 46 with deformation of the G-ring 48 which recovers to locate the parts in position and prevent inadvertent loss.

Figure 4 shows a third embodiment. In this case the part 14 is provided with a generally spherical head 60 projecting into the axial flow passage for engagement with the can 20.

Claims (9)

1. A gas tap comprising a plug or the like for controlling the rate of gas flow and located in a first passage, a flame failure device check valve located in a second passage extending generally transversely of the first, and an intermediate member located between the two valves and arranged so that axial displacement of a stem in the first passage displaces the intermediate member laterally of that passage to open the check valve, and characterised in that the intermediate member is physically connected to one or other of the parts.

2. A gas tap as claimed in Claim 1 wherein the intermediate member is a ring connected to one of the parts by a link

3. A gas tap as claimed in Claim 2 wherein said stem is provided with a cam which is axially fast with the stem said ring is supported on the stem adjacent the second passage. and said ring is arranged to be cam displaced into the second passage to operate said check valve.

4. A gas tap as claimed in Claim 1 wherein the intermediate member comprises a plug part projecting into said first passage to engage the cam therein, and said plug part is guided for axial movement in the second passage

5. A gas tap as claimed in Claim 4 wherein said plug part is integral with a further stem held in position by a frictional element engaged with said further stem.

6. A gas tap as claimed in Claim 1 wherein said intermediate member comprises a generally spherical head projecting into the first passage and formed on said check valve.

7. A gas tap substantially as described with reference to Figures 1 and 2 of the accompanying drawings.

8. A gas tap substantially as described with reference to Figure 3 of the accompanying drawings

9. A gas tap substantially as described with reference to Figure 4 of the accompanying draings.