GB2121156A

GB2121156A - Gas valves

Info

Publication number: GB2121156A
Application number: GB08216837A
Authority: GB
Inventors: Thomas Charles Cliff
Original assignee: UNITED GAS IND PLC
Current assignee: UNITED GAS IND PLC
Priority date: 1982-06-10
Filing date: 1982-06-10
Publication date: 1983-12-14
Also published as: GB2121156B

Abstract

A gas valve for an automatically controlled gas cooker comprises a solenoid-operated main shut-off valve on (11) having a valve plate (15) on a seat (16). A by-pass (20) extends around the valve (11) and has a manually-operated valve (21) connected therein. The maximum by- pass flow is restricted so that a cooker temperature of 170 DEG C-230 DEG C is achieved. In the event of a power failure the by-pass is opened allowing use of the oven at this low temperature. While the safety controls of the oven may not be working in the absence of electricity, the limited temperature achieved maintains safety. <IMAGE>

Description

SPECIFICATION Gas valves This invention relates to gas valves particularly for connection in the gas supply line of gas cookers.

The invention provides an electrically operated main shut-off valve for connection in a gas supply line in a gas cooker, a gas by-pass line by-passing said shut-off valve and a manually-controlled bypass valve in said by-pass line, said by-pass line and by-pass valve co-operating to allow only a reduced gas flow, less than the full flow allowed by said shut-off valve.

Preferably said reduced gas flow is selected so that a burner supplied by said by-pass line may burn uncontrolled in safety. For instance, an oven heated by said burner may be calculated to achieve maximum cooking temperatures between 1700C and 2300C.

Said by-pass valve may be opened by manually operable means which, when in the open position, indicates that the by-pass valve is open, or otherwise calls attention to itself.

A specific embodiment of the invention is diagrammatically shown in the accompanying drawing.

An electrically-operated shut-off valve (1 1 ) for a gas cooker is powered under the control of an automatic clock programmer (not shown) so that an oven of the cooker may be turned on and off at preset times. When the oven is to be turned on the programmer supplies electrical power on lines (12) to activate a solenoid coil (13). This pulls a rod (14) carrying a valve plate (15) away from a seat (1 6). Opening the valve establishes a flow path from gas inlet (17) to outlet (18).

Downstream of valve (11) is a flame failure valve (not shown) which only opens when a pilot is alight. The full flow from valve (11) may only therefore reach oven burners when it will be lit by the pilot.

Valve (11) also operates as a thermostatically controlled valve which is electrically controlled to vary the opening of plate (1 5) so that selected temperatures can be achieved. Typically the valve controlled by a thermo-couple or a temperature dependent resister. A valve of this kind is described in more detail in our co-pending Patent Application No. (PC440).

One disadvantage of electrically-operated programmer control over gas cookers is that when electrical power is lost, the cooker oven cannot be used, even though gas is still available. Valve (11) for instance can only be opened by electricity. In order to allow the oven to continue to be used in a power failure, in this embodiment a by-pass (20) provides a path for gas flow independent of the valve (11).

A manually-operated valve (21) in by-pass (20) may be opened at will to provide a manually controlled cooking facility. Preferably the valve (21) provides only two positions, fully closed and fully opened, and even at the fully opened position allows only a restricted gas flow to the oven. The maximum by-pass flow allowed is preferably calculated so that an oven temperature of between 1 700C and 230 C is achieved. This restriction is necessary because the thermostat control of the oven will not be working and the oven might become dangerously over-heated if a normal full flow continued uncontrolled. At the cooking temperature range proposed, a limited range of cooking processes is possible.

The automatic ignition system of the automatic oven will also not be working so that it will be necessary to light the oven manually.

As shown in the drawing, valve (21) is a rotary plug valve, but it is within the invention to use other forms of valve, for instance a valve plate manually moveable on and off a seat. The rotary valve (21) is operated manually by rotation of a knob (22). This is arranged so that when rotated into the open position it is clearly obvious to a user that the valve is still open. The knob or parts moveable therewith may, for instance, be moved to interfere with the operation of the normal controls of the oven. The control circuits for the programmer may be cut by a switch operated by the knob (22) or parts moveable therewith when the valve (21) is open, so that should power be restored while the valve (21) is open, it will be necessary for valve (21 ) to be manually closed before valve (11) will open and normal control is resumed.Where the valve (21) is a valve plate cooperating with a seat the manual control is a push/pull knob.

By this means some cooking facility is still available in a power failure.

In an alternative arrangement, valve (11) operates just as a shut-off valve, not a modulating thermostatically-controlled valve. In this arrangement another separate electricallyoperated thermostatically-controlled valve is included in series with valve (11) and the by-pass (20) by-passes both valves. In another arrangement the valve (11) operates as a shut-off valve with the by-pass (20) as shown in the drawing and a non-electrically-controlled thermostat valve is provided downstream of the arrangement. Such a non-electrically-controlled valve may have a bellows or expansible capsule operating the valve, the bellows or capsule being expanded by the expansion of a liquid in a phial exposed to the oven temperature.

1. An electrically-operated main shut-off valve for connection in a gas supply line in a gas cooker, a gas by-pass line by-passing said shut-off valve and a manually-controlled by-pass valve in said by-pass line, said by-pass line and by-pass valve co-operating to allow only a reduced gas fiow, less than the full flow of which the shut-off valve is capable.

2. A valve as claimed in claim 1, wherein said reduced gas flow is calculated to achieve a cooking temperature between 1 70 C and 2300 C.

3. A valve as claimed in claim 1 or claim 2,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Gas valves This invention relates to gas valves particularly for connection in the gas supply line of gas cookers. The invention provides an electrically operated main shut-off valve for connection in a gas supply line in a gas cooker, a gas by-pass line by-passing said shut-off valve and a manually-controlled bypass valve in said by-pass line, said by-pass line and by-pass valve co-operating to allow only a reduced gas flow, less than the full flow allowed by said shut-off valve. Preferably said reduced gas flow is selected so that a burner supplied by said by-pass line may burn uncontrolled in safety. For instance, an oven heated by said burner may be calculated to achieve maximum cooking temperatures between 1700C and 2300C. Said by-pass valve may be opened by manually operable means which, when in the open position, indicates that the by-pass valve is open, or otherwise calls attention to itself. A specific embodiment of the invention is diagrammatically shown in the accompanying drawing. An electrically-operated shut-off valve (1 1 ) for a gas cooker is powered under the control of an automatic clock programmer (not shown) so that an oven of the cooker may be turned on and off at preset times. When the oven is to be turned on the programmer supplies electrical power on lines (12) to activate a solenoid coil (13). This pulls a rod (14) carrying a valve plate (15) away from a seat (1 6). Opening the valve establishes a flow path from gas inlet (17) to outlet (18). Downstream of valve (11) is a flame failure valve (not shown) which only opens when a pilot is alight. The full flow from valve (11) may only therefore reach oven burners when it will be lit by the pilot. Valve (11) also operates as a thermostatically controlled valve which is electrically controlled to vary the opening of plate (1 5) so that selected temperatures can be achieved. Typically the valve controlled by a thermo-couple or a temperature dependent resister. A valve of this kind is described in more detail in our co-pending Patent Application No. (PC440). One disadvantage of electrically-operated programmer control over gas cookers is that when electrical power is lost, the cooker oven cannot be used, even though gas is still available. Valve (11) for instance can only be opened by electricity. In order to allow the oven to continue to be used in a power failure, in this embodiment a by-pass (20) provides a path for gas flow independent of the valve (11). A manually-operated valve (21) in by-pass (20) may be opened at will to provide a manually controlled cooking facility. Preferably the valve (21) provides only two positions, fully closed and fully opened, and even at the fully opened position allows only a restricted gas flow to the oven. The maximum by-pass flow allowed is preferably calculated so that an oven temperature of between 1 700C and 230 C is achieved. This restriction is necessary because the thermostat control of the oven will not be working and the oven might become dangerously over-heated if a normal full flow continued uncontrolled. At the cooking temperature range proposed, a limited range of cooking processes is possible. The automatic ignition system of the automatic oven will also not be working so that it will be necessary to light the oven manually. As shown in the drawing, valve (21) is a rotary plug valve, but it is within the invention to use other forms of valve, for instance a valve plate manually moveable on and off a seat. The rotary valve (21) is operated manually by rotation of a knob (22). This is arranged so that when rotated into the open position it is clearly obvious to a user that the valve is still open. The knob or parts moveable therewith may, for instance, be moved to interfere with the operation of the normal controls of the oven. The control circuits for the programmer may be cut by a switch operated by the knob (22) or parts moveable therewith when the valve (21) is open, so that should power be restored while the valve (21) is open, it will be necessary for valve (21 ) to be manually closed before valve (11) will open and normal control is resumed.Where the valve (21) is a valve plate cooperating with a seat the manual control is a push/pull knob. By this means some cooking facility is still available in a power failure. In an alternative arrangement, valve (11) operates just as a shut-off valve, not a modulating thermostatically-controlled valve. In this arrangement another separate electricallyoperated thermostatically-controlled valve is included in series with valve (11) and the by-pass (20) by-passes both valves. In another arrangement the valve (11) operates as a shut-off valve with the by-pass (20) as shown in the drawing and a non-electrically-controlled thermostat valve is provided downstream of the arrangement. Such a non-electrically-controlled valve may have a bellows or expansible capsule operating the valve, the bellows or capsule being expanded by the expansion of a liquid in a phial exposed to the oven temperature. CLAIMS

3. A valve as claimed in claim 1 or claim 2, wherein said by-pass valve has only two stable positions, fully open and fully closed.

4. A valve as claimed in any of claims 1 to 3, wherein said by-pass valve is a rotary plug valve or a valve plate movable on and off a seat.

5. A valve as claimed in any of claims 1 to 4, wherein said by-pass valve has manual means for opening and closing it, which manual means indicates that the by-pass valve is open or closed.

6. A valve as claimed in claim 5, wherein said manual means operates a switch which cuts electrical circuits supplying power to the main shut-off valve when the by-pass is open.

7. A valve as claimed in claim 5, wherein said manual means is moved to interfere with the operation of the normal controls of the cooker when the by-pass is open.

8. A valve as claimed in any of claims 1 to 7, wherein said main shut-off valve is a solenoid connected to be operated by an automatic clock programmer.

9. A valve as claimed in claim 8, wherein said main shut-off valve is also thermostatically controlled, the degree of opening of the valve being variable to achieve different cooking temperatures.

10. A valve as claimed in claim 8, wherein a separate thermostatically controlled valve is connected in the gas line of the said shut-off valve, and said by-pass extends around this valve also.

11. An electrically-operated main valve substantially as described hereinbefore with reference to the accompanying drawing.