GB2131126A - Operators for gas valves - Google Patents

Abstract

A remote operator for a gas burner on a cooker hob comprises a manual control knob (24) operating a push rod (25) bearing on a first expansible capsule (26). A length of semi-flexible capillary tube (21) joins capsule (26) to another capsule (20) forming therewith a sealed system filled with water. Capsule (20) operates another push rod opening a valve plate (14) of a gas valve. When in use, three or four burners of the hob all have similar operators, the manual control knobs (24) being mounted at a location remote from the valves. <IMAGE>

Description

SPECIFICATION Operators for gas valves This invention relates to operating means for gas valves, particularly operating means which can be located distant from the respective gas valves.

The invention provides operating means for a gas valve comprising a pair of expansible chambers connected by a length of capillary tube to form a sealed system containing an hydraulic fluid, manual means for applying pressure to one of said expansible chambers, the other of said expansible chambers being adapted to open and close a gas valve.

Preferably said manual means comprises a rotatable knob and a mechanical device for translating the rotation of the knob into pressure on the expansible chamber. Preferably, also, larger rotations of the knob produce greater pressures on the expansible chamber and in turn a larger opening of the gas valve.

The invention also extends to a hob for a gas cooker comprising a number of separate gas burners, each having a gas valve and operating means therefor, as set out above.

The capillary tubes may be led through complex paths to a location remote from the gas valves where the said manual means are mounted.

Specific embodiments of the invention are shown in the accompanying drawings, in which: Figure 1 is a diagrammatic representation of a gas valve and a remote operator therefor, Figure 2 is a section through one design of gas valve for use in the Fig. 1 arrangement, and Figure 3 is a section through one design of remote operator for use in the Fig. 1 arrangement.

Referring first to Fig. 1, a gas valve (11) providing gas to a hob burner of a gas cooker has a gas inlet (12), a gas outlet (13) and a valve plate (14) co-operating with a seat (1 5).

Springs (17, 17') tend to retain the plate on the seat. Push rod (18) extends between the valve plate and an expansible chamber (20), which is this case comprises a pair of flat flexible diaphragms secured around their edges but which alternatively could be a bellows. When the expansible chamber expands, it urges push road (18) in the sense to lift the valve plate off its seat and so allow gas to flow to the respective burner.

The interior of the expansible chamber (20) is connected to one end of semi-flexible capillary tube (21) the other end of which extends to a remote location where is a remote operator (23) for the gas valve. The remote operator comprises a rotatable manual control knob (24) operating a push rod (25) so that rotation of the knob is translated into axial motion of the rod. The end of the rod (25) impinges on one side of another expansible chamber (26), also shown as a pair of flexible diaphragms secured around their edges. Capillary tube (21) is connected to the interior of the expansible chamber (26), and the sealed system comprising the two expansible chambers and the capillary tube is filled with an hydraulic fluid. Preferably this fluid is of low viscosity, for instance it may be water with an antifreeze additive.

In use on a gas cooker hob, each of the three or four gas burners has associated with it a gas valve similar to valve (11). The valve may be conveniently mounted beneath the hob but need not, as previously has been the case, be mounted at the same location as the manual controls for the burner. The capillary tubes may then be run from the valves for a distance which may be as much as 3 feet to a location, for instance, above the hob or at the front of the hob, where the remote operators for the valves are mounted. The capillary tubes are semi-flexible, formed for instance of thin copper tubing, flexible enough to be bent to run in a complex path around the hob if required. The tubes may be collected together into a single plastic casing and run as a single unit for part of their paths.

By this means the manual operating knobs for the individual burners may be mounted wherever the gas cooker designer pleases without the previous limitation to being located at the same place as the gas valves.

When any knob is rotated in one sense the expansible chamber (26) is compressed, so compressing the hydraulic fluid in the sealed system. This causes the expansible chamber (20) at the other end of the system to expand so opening the gas valve. Rotation in the opposite direction releases the pressure, so that spring (17') may close the gas valve and spring (17) returns the expansible chamber (20) to its unexpanded condition. This arrangement provides accurate control of the amount of the gas valve opening from the degree of rotation of the knob, as with previous direct operation systems.

The control knob may effect its translation into forward movement of the push rod through a trapped screw threaded connection or through a cam.

A more specific arrangement of the gas valve (11) is shown in Fig. 2, wherein similar parts have the same reference numerals as used in Fig. 1.

A more specific design of the remote operator (23) is shown in Fig. 3. A control knob (not shown) is mounted on a shaft (30) having a blind hole at one end in which is located a spring (31). Also in the blind hole is seated one end of a push rod (25), pinned at (32) to turn with the shaft (30) when the shaft is depressed. Push rod (25) carries another pin (36) which engages a cam face (37) on stationary structure, so that as the push rod is turned the pin (36) is urged axiaily downwards from the position shown, carrying with it the push rod. A collar (33) on the push rod engages one end of a spring (34) which resists the axial motion of the rod. The other end of rod (25) engages a pressure pad (35) which presses upon the expansible chamber (26) which is as described with reference to Fig. 1. Pressure on and rotation of the knob and shaft (30) therefore compresses the expansible chamber (26) and pressurizes the hydraulic fluid.

In an alternative arrangement (not shown) the gas valve is thermostatically controiled, including a temperature-responsive element which tends to close the valve when a selected temperature is achieved. In this arrangement, a remote operator is similar to that described in relation to Figs. 1 or 3, but operates to set the selected temperature into the gas valve. The knob is therefore calibrated in temperature settings.

While the invention has been described in relation to providing remote control for the gas valves of a gas cooker hob, it will be appreciated that it relates to remote controlling of gas valves for any purpose, e.g. in gas fires or boilers.

Claims (11)

1. Operating means for a gas valve comprising a pair of expansible chambers connected by a length of capillary tube to form a sealed system containing an hydraulic fluid, and manual means for applying pressure to one of said expansible chambers, the other of said expansible chambers being adapted to open and close a gas valve.

2. Operating means as claimed in claim 1, wherein said manual means comprises a rotatable knob and a mechanical device for translating rotation of the knob into pressure on the said one expansible chamber.

3. Operating means as claimed in claim 2, wherein said mechanical device comprises a trapped screw operating on a push rod.

4. Operating means as claimed in claim 2, wherein said mechanical device comprises a cam operating on a push rod.

5. Operating means as claimed in claim 4, wherein said push rod is rotatable with the knob, and carries a pin riding on said cam, whereby the rotation causes axial movement of the push rod.

6. Operating means as claimed in any of claims 3 to 5, wherein said push rod bears on the said one expansible chamber.

7. Operating means as claimed in any of claims 1 to 6, wherein said capillary tube is flexible enough to be bent to run in a complex path.

8. Operating means as claimed in claim 7, wherein said capillary tube is of the order of three feet long.

9. Operating means as claimed in any of claims 1 to 8, wherein said sealed system is filled with water.

1 0. Operating means as claimed in any of claims 1 to 9, wherein said other one of the expansible chambers operates a valve push rod operating on a valve plate of a gas valve, to lift said plate off a seat.

11. A gas cooking hob comprising a number of separate gas burners each having a gas valve and operating means therefor, as claimed in any of claims 1 to 10.

1 2. A gas cooking hob as claimed in claim 11, wherein the capillary tubes are led through complex paths to a location remote from the gas valves where the said manual means are mounted.

1 3. Operating means for a gas valve substantially as set forth hereinbefore with reference to the accompanying drawings.