GB2278913A

GB2278913A - Control of gas appliances

Info

Publication number: GB2278913A
Application number: GB9311219A
Authority: GB
Inventors: Alan Beaton
Original assignee: JETMASTER FIRES Ltd
Current assignee: JETMASTER FIRES Ltd
Priority date: 1993-06-01
Filing date: 1993-06-01
Publication date: 1994-12-14
Anticipated expiration: 2013-06-01
Also published as: GB9311219D0; FR2706019B1; GB2278913B; FR2706019A1

Abstract

The invention relates to improvements in the means of controlling gas appliances such as decorative gas fires and the like and more particularly to battery operated control means. A gas appliance comprises a burner, means of supplying gas to said burner and control means 14 operable to open and close the gas supply to the burner. The control means includes a battery 11 connected to a first solenoid valve 15 via a first switch 18. The first solenoid valve is connected to the gas supply, such that when the first switch is activated the battery gives a power surge to the first solenoid valve to actuate it to either allow gas to flow to the burner or prevent it from flowing. The battery may be connected to the switches by cabling or the switches and battery may be incorporated in the appliance. The battery may itself be actuated via remote control. A second valve 16 for high/low operation may be included, the second valve being operated by a second switch 19 also connected to the battery. <IMAGE>

Description

IMPROVEMENTS IN THE CONTROL OF GAS APPLIANCES The invention relates to improvements in the means of controlling gas appliances such as decorative gas fires and the like and more particularly to battery operated control means.

Many prior art gas fires have their gas controls fitted under the fire burner tray at the front of the fire, which are covered by a front panel. The panel can be opened to reveal the controls which can then be turned to allow the gas to flow around the mock coals or logs. This type of control means suffers from the disadvantage that the user has to place a hand very close to the heated parts of the fire. Although many such fires are designed to avoid burning, some users are often hesitant. This type of control means can prove to be particularly difficult for the elderly or disabled as it is necessary to bend or even kneel in front of the fire and operate small control knobs.

In an effort to overcome these disadvantages, prior art devices have been developed which exert some "remote" control over the state of the appliance. These generally have relied upon either an EMF of a few millivolts generated from an internal thermocouple in juxtaposition with a pilot burner and are controlled by a handset using ultraviolet line of sight transmission or ultra-sonic transmission. However, such controls have been limited to an ON/OFF capability and if the remote control is mislaid, the fire cannot be controlled.

Other control devices have been tried which overcome the reliance upon minute voltages by using control valves which are operated from an AC mains supply. However, because of the safety requirements for the installation of mains electricity and equipment powered by it, the installation is much more expensive and requires additional skills by the gas installer. Furthermore, many people are nervous of operating gas appliances which involve the use of mains electricity because of the perceived inherent risks.

Furthermore, a mains controlled switch would render the fire or appliance completely useless when there is a power cut. Since power cuts often occur in cold weather, this can cause considerable discomfort, particularly for old people.

It is thus an object of the present invention to overcome the aforesaid disadvantages.

According to the invention there is provided a gas appliance comprising a burner, means of supplying gas to said burner and control means operable to open and close the gas supply to the burner, said control means comprising a battery connected to a first solenoid valve via a first switch, said first solenoid valve being connected to the gas supply, such that when the first switch is activated the battery gives a power surge to the first solenoid valve to either allow gas to flow to the burner or prevent it from flowing.

The invention will now be described, by way of example only, with reference to the accompanying drawings in which : Figure 1 is a schematic representation of a gas appliance controller according to the invention; Figure 2 is a schematic representation of an electrical circuit used to operate solenoid valves of the gas appliance controller of Figure 1.

Figure 3 is a schematic representation of a remote controlled gas appliance controller according to the invention.

A typical decorative open fronted gas fire is constructed to be installed in a domestic fireplace opening. The fire includes a plurality of simulated fuel elements, such as coal or logs, positioned with gaps therebetween. The fire has a fire box containing the fuel elements beneath which is located the burner 10 which is supplied with gas or a gas/air mixture. Situated in the area of the burner 10, is a pilot burner 11 which ignites the gas as it exits the ports of the burner 10. The pilot burner 11 can optionally be fitted with a flame sensing device of a known type.

Referring to Figure 1, in a gas fire fitted with the invention gas is supplied from the gas mains supply to gas fire inlet 12. A manual control valve 13 is provided in case of emergency or failure of the main gas controller 14, and to control the pilot burner 11.

The controller 14 comprises two solenoid valves 15, 16, which are low voltage DC operated solenoid valves. The first solenoid valve 15 is operable to open and close the gas supply, whereas the second solenoid valve 16 causes the supply to change from a large bore supply to a small bore supply, so altering the amount of gas which can pass through to the burner 10. The burner 10, pilot burner 11 control valve 13 and solenoid valves 15, 16 are all connected by gas supply pipes 20.

The solenoid valves, 15, 16 are powered by a battery 17, which is typically a three volt battery source consisting of two AA size cells. The control of the solenoid valves 15, 16 is effected through switches 18, 19. These are preferably double pole switches with spring return to centre position.

The battery 17 and switches 18, 19 are housed in a control box which can be used in conjunction with up to, say, five metres of cable so that the control box can be mounted in a convenient position for the user.

Alternatively, the battery and switches may be integrally fitted with the fire.

In operation, activation of the first switch 18 will give an initial power surge to the solenoid 15 which will operate to allow gas to flow to the burner. The reversal of operation is achieved by the crossover switch wiring which reverses the polarity of the DC voltage from the battery and therefore reverses the position of the solenoid actuator.

The second switch 19 operates the second solenoid valve 16 in the same fashion.

Thus, the two switches have four possible combinations of ON/OFF, HIGH/LOW as controls to the fire.

It is necessary for the fire to have a standing pilot light so that the ignition of the burner is automatic once ON is selected.

Since the battery 17 is only required for the initial surge of power, it is unlikely to go flat for some time.

This is advantageous, particularly from a cost point of view, in that the batteries need replacing very infrequently. Furthermore, the use of solenoids means that the power is only needed for a very short period of time for activation. The batteries can be replaced as and when required by the user, thus avoiding the need to call out a skilled workman to maintain the fire.

The use of batteries which have a long operational life is dependent on spring to centre switches which only supply current to the time when the switch is pressed to a particular mode. The time required for the control to work is about half a second. Thus, hundreds of selections are possible before replacements batteries are required.

Since no mains voltage is involved, the system can safely be operated as a fixed control box, or a more mobile one if required for a chairbound jer, without safety problems. Another variant could be the use of the low voltage system in combination with a remote handset. This would be achieved by the use of a circuit typically illustrated in Figure 3. In this case the user handset 23 houses the two switches which control wireless emissions to a receiver unit 21 mounted on or adjacent to the fire and connected to the solenoid valves 15 and 16 by wires 22 from a local battery supply inside the receiver.

The dispensing of mains voltage allows non-qualified people to install the electrical items, which also require no earth connection. No high voltage and very small batteries ensure that under fault conditions there is insufficient energy available to cause fear of accidental ignition of any leaking gas.

Furthermore, the wired system is not prone to interference as are some of the receivers of wireless transmissions, so it is not sensitive to any type of outside random operation. Furthermore, the hard wired system means that there is no travelling handset to mislay.

Furthermore, if the batteries become discharged, the fire will not light from OFF. If the fire is alight when the discharged state is reached, the fire can be extinguished via the manual control without danger.

Claims

CLAIMS:

1. A gas appliance comprising a burner, means of supplying gas to said burner and control means operable to open and close the gas supply to the burner, said control means comprising a battery connected to a first solenoid valve via a first switch, said first solenoid valve being connected to the gas supply, such that when the first switch is activated the battery gives a power surge to the first solenoid valve to either allow gas to flow to the burner or prevent it from flowing.

2. A gas appliance as claimed in Claim 1 in which the control means is further operable to change the rate of supply of gas to the burner.

3. A gas appliance as claimed in Claim 2 in which the control means further comprises a second solenoid valve connected to the battery and to the gas supply and a second switch, such that when the second switch is activated the battery gives a power surge to the second solenoid valve which causes the supply to change from a large bore supply to a small bore supply or vice versa.

4. A gas appliance as claimed in any one of Claims 1 to 3 in which the battery and switchable switches are integrally fitted with the appliance.

6. A gas appliance as claimed in any one of Claims 1 to 3 in which the battery and switch or switches operate the solenoid by remote control.

7. A gas appliance substantially as hereinbefore described with reference to and as shown in the accompanying drawings.