GB2301429A

GB2301429A - Gas cooking hob

Info

Publication number: GB2301429A
Application number: GB9510893A
Authority: GB
Inventors: Gerard Ryder
Original assignee: New World Products Inc
Current assignee: New World Products Inc
Priority date: 1995-05-30
Filing date: 1995-05-30
Publication date: 1996-12-04
Also published as: GB9510893D0

Abstract

A gas cooking hob comprises at least one gas burner, a lid which may be opened to provide access to the burner and which may be closed over the gas burner, a gas cut-off valve operated by said lid for cutting-off a gas supply to the gas burner when the lid is closed, a battery operated ignition circuit 1 for causing the gas burner to be lit when gas is supplied to it, and a capacitor charging circuit for causing a capacitor C thereof to be charged when the lid is closed and which is caused to be discharged to activate the ignition circuit when the lid is opened, whereby any gas being inadvertently supplied to the gas burner is caused to be lit to prevent gas leakage. Preferably the capacitor C takes the form of a high capacitance memory back-up capacitor.

Description

Gas Cookers This invention relates to gas cookers and relates more specifically to gas cooking hobs. The hob may be an independent unit or it may be part of a cooker which incorporates one or more ovens.

It is known to fit such hobs with lids which open to provide access to one or more gas burners, and which when closed cover the gas burners.

Safety measures in the form of a gas stay-off valve have been provided in such gas cooking hobs which cuts-off the gas supply to the hob when the lid is closed and which maintains the gas supply off when the lid is raised should any one or more of the gas taps associated with the gas burners have inadvertently been left on.

The gas stay-off valves used in such gas cooking hobs are relatively expensive items and it is an object of the present invention to provide a gas cooking hob in which the gas stay-off valve can be dispensed with and replaced by a simple cut-off valve.

According to the present invention there is provided a gas cooking hob comprising at least one gas burner, a lid which may be opened to provide access to said gas burner and which may be closed over said gas burner, a gas cut-off valve operated by said lid for cutting-off a gas supply to said gas burner when said lid is closed, and a battery operated ignition circuit for causing said gas burner to be lit when gas is supplied to it, a capacitor charging circuit being provided which causes capacitor means thereof to be charged when said lid is closed and which is caused to be discharged to activate said ignition circuit when said lid is opened, whereby any gas being inadvertently supplied to said gas burner is caused to be lit.

In carrying out the invention it may be arranged that said capacitor charging circuit comprises a changeover switch which is operated by said lid, said switch causing said capacitor means to be charged via resistor means when said lid is closed, and said switch causing said capacitor means to be connected to said ignition circuit when said lid is opened.

In a preferred arrangement for carrying out the invention it is arranged that said capacitor means takes the form of a memory back-up capacitor.

An exemplary embodiment of the invention will now be described, reference being made to the accompanying drawing which is a partially block schematic circuit diagram of a capacitor charging circuit and battery operated ignition circuit for incorporation into a gas cooking hob in accordance with the present invention.

In the drawing there is depicted a battery operated ignition circuit 1 which is of conventional form, and which is provided with a pair of input terminals 2 which in a conventional gas cooking hob would be connected to a battery via one or more switches which are associated with the gas taps of the hob and are operated when an associated gas tap is turned ON. The ignition circuit 1 is also provided with a plurality of outputs 3 for connection to ignition electrodes associated with each of the gas burners of the gas cooking hob. Thus, under normal circumstances, when a switch associated with a gas tap is operated, the ignition circuit 1 is activated to produce sparks at the electrodes connected to the outputs 3.

In accordance with the present invention, the ignition circuit 1 is connected to a capacitor charging circuit consisting of a capacitor C, a changeover switch S, and a charging resistance R connected in series across a battery B. Typically the capacitor C will have a value of 1 Farad, the resistor R will have a value of 8 ohms, and the battery will have a value of 3 volts.

The changeover switch S is adapted to be operated by the lid (not shown) of a cooking hob such that when the lid is closed the switch S connects the charging resistance R to the capacitor C to cause the capacitor C to be charged, and when the lid is opened the switch S connects the charged capacitor C across the input terminals 2 of the ignition circuit 1, thereby causing the ignition circuit 1 to be activated to cause sparks to be generated at the spark electrodes connected to the outputs 3, and associated with the various gas burners of the gas hob. The affect of this is that if any of the gas taps (not shown) of the hob had been inadvertently left ON when the lid had been closed, when the lid is opened the gas burner or burners associated with the tap or taps which had been left on will be caused to be ignited, thereby removing any danger of gas leakage. The advantage of this is that the normal stay-off valve provided in gas cooking hobs for preventing such gas leakage is not now required and can be replaced by a simple lid operated cut-off valve, such as a poppet valve, of much reduced cost.

In accordance with a preferred aspect of the present invention it has been appreciated that the capacitor C of the charging circuit shown the drawing is preferably constituted by a high capacitance memory back-up capacitor of the kind made by Panasonic and available from component supply companies such as RS.

It will be appreciated that the exemplary embodiment of the invention which has been described has been given by way of example only and may be adapted to suit any particular application.

Claims

1. A gas cooking hob comprising at least one gas burner, a lid which may be opened to provide access to said gas burner and which may be closed over said gas burner, a gas cut-off valve operated by said lid for cutting-off a gas supply to said gas burner when said lid is closed, and a battery operated ignition circuit for causing said gas burner to be lit when gas is supplied to it, a capacitor charging circuit being provided which causes capacitor means thereof to be charged when said lid is closed and which is caused to be discharged to activate said ignition circuit when said lid is opened, whereby any gas being inadvertently supplied to said gas burner is caused to be lit.

2. A hob as claimed in claim 1, in which said capacitor charging circuit comprises a changeover switch which is operated by said lid, said switch causing said capacitor means to be charged via resistor means when said lid is closed, and said switch causing said capacitor means to be connected to said ignition circuit when said lid is opened.

3. A hob as claimed in claim 1 or claim 2, in which said capacitor means takes the form of a memory back-up capacitor.

4. A gas cooking hob incorporating a gas ignition circuit substantially as hereinbefore described with reference to the accompanying drawing.