GB2355785A

GB2355785A - Control assembly for gas heating appliances

Info

Publication number: GB2355785A
Application number: GB9925704A
Authority: GB
Inventors: Grahame Bentley
Original assignee: THERMACO Ltd
Current assignee: THERMACO Ltd
Priority date: 1999-10-30
Filing date: 1999-10-30
Publication date: 2001-05-02
Anticipated expiration: 2019-10-30
Also published as: GB9925704D0; GB2355785B

Abstract

The control assembly comprises a valve 8 and a control device 9 for operating the valve. The valve comprises a valve body 10 having a gas inlet 11, a pilot gas outlet 12 and a main gas outlet 13. A first valve member 14 is movable between a first position in which it closes the supply of gas from the inlet to the pilot and main outlets and a second position in which it allows gas to flow from the inlet to the pilot outlet and towards the main outlet. A magnetic coil 16 is energised in response to heat from a pilot flame to hold the first valve member in its second position and a second valve member 17 moves the first valve member from its first position to its second position and controls the supply of gas from the inlet to the main outlet. The control device 9 comprises a first angularly displaceable cam 18. The second valve member is urged by resilient means into contact with the first cam and is movable relative to the valve body by angular displacement of the first cam.

Description

2355785 "Control Assembly for Gas Heating Appliances" This invention

relates to a control assembly for a gas heating appliances, particularly but not exclusively gas fires.

According to the invention there is provided a control assembly for gas heating appliances, comprising a valve and a control device for operating the valve, the valve comprising a valve body having a gas inlet, a pilot gas outlet and a main gas outlet, a first valve member movable between a first position in which it closes the supply of gas from the inlet to the pilot and main outlets and a second position in which it allows gas to flow from the inlet to the pilot outlet and towards the main outlet, a magnetic coil which is in use energised in response to heat from a pilot flame to hold the first valve member in its second position and a second valve member for moving the first valve member form its first position to its second position and for controlling the supply of gas from the inlet to the main outlet and the control device comprising a first angularly displaceable cam, the second valve member being urged by resilient means into contact with the first cam and being movable relative to the valve body by' angular displacement of the first cam.

Preferred and/or optional features of the invention are set forth in Claims 2 to

5, inclusive.

The invention will now be more particularly described, by way of example, with 2 reference to the accompanying drawings, in which:

Figure I is a sectional view through a valve of one embodiment of control assembly according to the invention, the valve being shown in a first condition, Figure 2 is a view similar to Figure I but with the valve shown in a second condition, and Figures 3A to 3C show three cams, respectively, of a control device for operating the valve shown in Figures I and 2.

The control assembly shown in the drawings comprises a valve 8 shown in Figures I and 2 and a control device 9 shown in Figures 3A to 3C. The valve 8 comprises a valve body 10 having a gas inlet 11, a pilot gas outlet 12 and a main gas 15outlet 13. The pilot outlet 12 is between the inlet I I and the main outlet 13 as considered along the longitudinal extent of the valve body 10. i The valve 8 also comprises a first valve member 14 which is movable between a first position (shown in Figure 1) in which it closes against a valve seat 15 disposed between the inlet 11 and the pilot outlet 12 to close a supply of gas from the inlet I I to the pilot and main outlets 12 and 13 and a second position (shown in Figure 2) in which it allows gas to flow from the inlet I I to the pilot outlet 12 and towards the main outlet 3 13. A magnetic coil 16 is energised by a thermo-couple (not shown) which is, in use, heated by the pilot flame. The coil 16, when energised, will hold the first valve member 14 in its second position.

The valve 8 also comprises a second valve member 17, which has a push rod 17a at its inner end to move the first valve member 14 from its first to its second position. The second valve member 17 also controls the supply of gas from the inlet I I to the main outlet 13.

The control device 9 comprises three cams 18, 19 and 20 secured to a common shaft. The second valve member 17 is urged by a compression spring (not shown) housed in the valve body 10 into contact with the cam 18. The cam 18 is an eccentric cam and is shown in t he "off 'position of the control assembly. In this position, the cam 18 engages a stop 21. When the cam 18 is displaced angularly in a clockwise direction, it will be apparent that the cam forces the second valve member 17 into the valve body against the urging force of the spring.

The cam 19 co-operates with a switch 22. The cam 19 has a small indentation 23 in a position of the cam corresponding to the "off' position of the control assembly.

This allows the switch 22 to open in this position. When in other positions, the cam 19 turns the switch 22 on. The switch 22 is in the electrical supply circuit for the thermo couple.

4 The cam 20 has a projection 24 which co-operates with a further switch 25 to turn the switch 25 on when the control assembly is in a fully "on" position. The switch is provided in a spark ignition circuit (not shown) and, therefore, when the control assembly is a "on" position, this switch 25 will energise a spark ignition device (not shown). The common shaft on which the cams 18, 19 and 20 are secured can be driven by a pmdc motor which is controlled either by an infra-red remote control device or by a series of switches on the outside of the appliance. Alternatively, the common shaft can be operated manually. The electrical circuits can either be powered by a battery pack or a dc transformer driven by the mains supply. The charge of the battery system can be supported and maintained by a solar cell and/or a Peltier device.

In operation, the control device is moved initially from its "off' position to its fully "on" position. The cam 18 will force the second valve member 17 to the left as viewed in Figure 3A. The push-rod 17a at the end of the second valve member 17 will engage the first valve member 14 and move this from its first to its second position.

Gas will be supplied from the inlet I I to the pilot outlet 12 but the main outlet 13 will be closed by the second valve member 17. The cam 19 will move away from its position shown in Figure 3B so as to turn on switch 22. This allows the thermo-couple to energise the coil 16. The cam 20 will co-operate with the switch 25 to turn this latter switch on and energise the spark generator. The spark generator will ignite the pilot flame. The control device must be kept in its fully "on" position for a few seconds to allow sufficient current to be generated by the thenno-couple to energise the coil 16 which will then hold the first valve member 14 in its second position. The shaft can then be angularly displaced in order to move the second valve member 17 to a position in which it controls the flow gas from the inlet I I to the main outlet 13. The cam 19 will keep switch 22 turned on so that the thermo-couple circuit remains energised, but 5 the cam 20 will allow switch 25 to turn off thereby de-energising the ignition generator.

The control assembly may be of modular design to allow for upgrading from a basic mechanical system to a fully remote controlled system.

Claims

6 CLAIMS

1. A control assembly for gas heating appliances, comprising a valve and a control device for operating the valve, the valve comprising a valve body having a gas inlet, a pilot gas outlet and a main gas outlet, a first valve member movable between a first position in which it closes the supply of gas from the inlet to the pilot and main outlets and a second position in which it allows gas to flow from the inlet to the pilot outlet and towards the main outlet, a magnetic coil which is in use energised in response to heat from a pilot flame to hold the first valve member in its second position and a second valve member for moving the first valve member form its first position to its second position and for controlling the supply of gas from the inlet to the main outlet and the control device comprising a first angularly displaceable cam, the second valve member being urged by resilient means into contact with the first cam and being movable relative to the valve body by angular displacement of the first cam.

2. A control assembly as claimed in Claim 1, wherein the control device includes a first switch for energising a spark generator and a second cam for closing the switch when the first cam forces the second valve member into a position in which it moves the first valve member into its second position.

3. A control assembly as claimed in Claim I or Claim 2, wherein a thennocouple 7 responsive to a pilot flame is provided for energising the coil and wherein the control device includes a second switch for energising the thermocouple and a third cam surface for closing the second switch other than when the control device is in an off position. 5 4. A control assembly as claimed in any one of the preceding claims, wherein the control device includes a motor for rotating the or each cam.

5. A control assembly as claimed in Claim 4, wherein the motor is operable by 10 a remote control device.

6. A control assembly for gas heating appliances, substantially as hereinbefore described with reference to the accompanying drawings.