GB2094937A - Valve with manual override - Google Patents

Abstract

A gas cooker valve (1) has a solenoid-driven actuator (8) to selectively close or open the main channel (5) between gas inlet (3) and outlet (4). An auxiliary channel (9), unaffected by the condition of the actuator, is normally closed by a resilient pad (12) on a solid pad (13) fixed to a rod (14); however, the pads can be moved manually away from the auxiliary channel and then latched to permit gas to by-pass the main channel when closed, e.g. during a failure of the electricity supply. <IMAGE>

Description

SPECIFICATION Valve with manual override This invention relates to valves, used in gas burning appliances, which employ actuators responsive to electrical devices and it relates especially, though not exclusively, to such valves as may employ solenoid-driven actuators. Such valves may for example be associated with automatic timing controls for gas ovens.

One difficulty which arises with the use of such valves in gas-burning appliances is that failure of the electricity supply causes the valve to close and thus shuts off the gas supply, disabling the appliance. This invention aims at reducing the above difficulty and, in accordance with the invention, there is provided a gas valve including an inlet, an outlet and a channel, linking said inlet with said outlet, and which channel can be selectively closed or opened by means of an actuator responsive to an electrical device, a bypass channel linking said inlet with an auxiliary outlet, the by-pass channel being unaffected by the condition of said actuator, and a closure member which is normally biased so as to close said auxiliary outlet but which can be manually moved, against the bias, to open said auxiliary outlet and latched in the open condition.

In orderthat the invention may be clearly understood and readily carried into effect, one embodiment thereof will now be described, by way of example only, with reference to the accompanying drawing which shows, in schematic, cross-sectional view, a valve in accordance with one example of the invention.

Referring now to the drawing, a gas valve, shown generally at 1, comprises a housing 2 formed with a gas inlet 3, a gas outlet 4, and a channel 5 linking the inlet to the outlet via a gallery 6. The channel 5 can be selectively closed or opened by means of an actuator 7 which is responsive to an electrical device, in this example a solenoid 8. The solenoid/actuator assembly is secured, in gas-tight manner, within an aperture in a side wall of housing 2.

As thus far described, the valve is conventional.

In accordance with this example of the invention, however, there is provided an auxiliary channel 9 which links the inlet 2 to the outlet 3 via gallery 6.

The auxiliary channel 9 is not affected by the condition of the actuator 7 (i.e. it is not influenced by whether the channel 5 is opened or closed) but it is normally closed by means of a closure member 10 which is biased, by means of a spring 11, to its channel closing position shown in the drawing. The closure member 10 incorporates a resilient closure pad 1 2 supported by a solid pad 1 3 formed on the end of a rod member 14 which passes through an aperture in a side wall of housing 2, and the spring 11 surrounds the rod member 14 as shown, within the housing 2. The rod member is manually slidable relative to the housing to permit the pad 1 3 to be withdrawn from the position shown in the drawing (in which it closes the auxiliary channel 9) against the biasing force of spring 11, to open the auxiliary channel.Latching means (not shown) of any convenient kind can be produced to latch the rod member 14 in its withdrawn position.

Thus, in the event of a failure of the electricity supply, which would automatically cause the actuator 7 to close the channel 5 in accordance with safety regulations, the gas-fired appliance can be used by manually withdrawing and latching the rod member 14 to open the auxiliary channel 9.

It will be appreciated that the rod member 14, being slidable through its aperture in the housing 2, has to be provided with a suitable seal which accommodates the sliding movements and provides a gas-tight seal at all positions that can, in practice, be assumed by the rod member 14. In this example, the rod member 14 is shown to be formed with a recess 1 5 which houses a sealing ring 16, and the inner surface 1 7 of the aperture, through which the rod member 14 passes, is rendered compatible with the material of which the ring 1 6 is formed, so as to ensure proper sealing. Additional or alternative sealing arrangements may be provided, however, without departing from the scope of the invention.

Those skilled in the art will readily appreciate that the valve may also incorporate other devices, such as closure means responsive to flame alight detectors, arranged to cut off the gas supply if the main burner, or an associated flame, is extinguished. It will also be appreciated that thermostatic control may be incorporated in, or associated with the valve 1 and that the solenoid 8 may be responsive to a timer mechanism, especially in circumstances where the value is to be used in conjunction with a gas cooker.

In this example, the diameter of the by-pass channel 9 is substantially the same as that of the main channel 5, but other dimensions could be used if desired. In practice, the rod member 14 is preferably mounted within a threaded bush which is secured within the relevant aperture in housing 2. In this case, it is the internal surface of the bush which co-operates with the sealing ring 1 6 to form a gas-light seal. The inner end of the threaded bush conveniently can be used to provide a surface against which the spring 11 can bear to urge the pad 1 2 into contact with the mouth of channel 9. The pressure exerted by the spring 11 has to be sufficient to close the auxiliary channel 9 even when a test pressure is applied to the inlet 2.

As described hitherto, the rod member 14 has to be unlatched manually when normal operation of the gas-burning device is to be restored.

Alternatively or additionally however, the unlatching may be effected automatically, by means such as a solenoid which incorporates a cut-out device to shut off the supply of electricity thereto after operation when power is restored.

As mentioned previously, the external mechanism associated with the rod members 1 4 may take any convenient form. For example, it is possible to use a sliding push-pull control in the form of a ramp which changes the motion and gives a mechanical advantage on the rod member.

Alternatively, a simple cam device could be used so that a projecting knob may be twisted to draw the pad 13 away from the mouth of channel 9. In general, however, any convenient form of mechanism can be used.

Claims (7)

1. A gas valve including an inlet, an outlet and a main channel linking said inlet with said outlet, and which main channel can be selectively closed or opened by means of an actuator responsive to an electrical device, a by-pass channel being unaffected by the condition of said actuator, and a closure member which is normally biased so as to close said auxiliary outlet but which can be manually moved, against the bias, to open said auxiliary outlet and then can be latched in the open condition.

2. A valve according to Claim 1, wherein the auxiliary outlet communicates with a chamber linking the main channel and the outlet.

3. A valve according to Claim 1 or Claim 2, wherein the closure member comprises a plate biased against the auxiliary outlet by spring means.

4. A valve according to any one of the preceding claims, wherein the by-pass channel has substantially the same flow characteristics as the main channel.

5. A valve according to any one of the preceding claims, wherein the closure member can be unlatched manually.

6. A valve according to any one of the preceding claims, wherein the closure member can be unlatched by a solenoid which incorporates a cut-out device to shut off the supply of electricity thereto after operation and when unlatching is required.

7. A gas valve substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.