Gas appliance

Abstract: Improvements on instant lighting devices in built-in safety valves used in gas appliances; particularly in house hold appliances with one or more burners. Each of these devices includes a printed circuit (2) equipped with a selector (5) for the feed by means of a trigger (6), to a valve which controls the flow of gas to the burner once an external button (3) is pressed. The burner is lit by means of time delay (10) or flame ionization, and at the same instant an auxiliary current supply to the magnetic group of the valve is produced. This current is timed, and it replaces the electrical current generated by a thermocouple (4) when it is heated by the flame of the burner.

Description: This invention deals with a gas appliance according to the preamble of claim 1. Certain safety valves based on flame control are already familiar. These valves are used in household appliances running on gaseous fuel, are of the thermoelectric type, and utilize electrical energy generated by the heating of a thermocouple, either by the flame of a pilot light, or by the bumer itself. The electrical energy generated flows through the coil of an electromagnetic assembly, and this action makes it possible for safety valve to remain open, allowing for the flow of the gas to the burner it controls. The absence of a flame and the outflow of gas that is not burned, make it impossible for the thermocouple to remain hot, and therefore no electrical energy allowing for the activacion of the electromagnet is produced. As a result, the valve controlling the flow of the gas closes. It must be kept in mind that the electromagnetic system does not generate sufficient energy to attract the safety valve on the assembly. It produces only enough energy to keep the valve closed, which therefore must be activated manually to overcome the force of the built-in spring. This spring is activated, shutting off the gas, when the temperature is not high enough to obtain the thermoelectric energy necessary to maintain the safety valve open. In reality, the magnetic force of attraction should only be slightly greater than the force of the tension caused by the spring of the safety valve; this level of force is achieved with very low consumption of electricity. Japanese publication JP-A-226525 shows how to ensure ignition by burner, prevent the releasing of unburnt gas and to contrive safety, by incorporating a timer circuit continued igniting operation for a predetermined period of time necessary for the ignition of a burner even when the igniting operation is instantaneous, into an igniting circuit. When a burner is ignited instantaneously by the spark of an igniting circuit, a flame detecting circuit is operated to supply the voltage of a battery to the coil of a solenoid safety valve through a transistor and hold the safety valve in the given time valve opering condition of a first timer circuit while a solenoid safety valve is held in the valve opening condition by the conduction of the coil affected by a predetermined electromotive force from a thermocouple heated by the burner, whereby the combustion of the burner is continued. When the burner is not ignited instantaneously by the spark of the ignited circuit, a flame rod does not carry current, and a flame detecting circuit is not operated, whereby the voltage of the battery is not supplied to the coil, the solenoid safety valve is closed quickly and the burner may be maintained in the condition of shut-off. Through U.S.A. patent no. 3 544 247 we know that a fuel burner is operatively connected to a burner primary control means and operates in response to the condition of a controller. The burner primary control means is of a type that includes a direct current power supply means to supply all of the necessary operating power for its amplifiers and control relays. Connected to the burner primary control means is a power storage means that obtains direct current power from the direct current power supply means of the burner primary control means and which stores this power over a period of time. In the event of a momentary power loss to the burner primary control means, the power storage means feeds direct current power back to the primary control means keeping it energized for a short interval. Through Japanese publication no. JP-A-63306311 we know how to surely keep safety and enable positive combustion in a combustion device such as hot water heater by a method wherein a fuel valve is kept open during a desired auxiliary time after ignition and this auxiliary time is extended by desired time when ignition of a burner is confirmed. First and second fuel valves are opened under a pushing operation of a hot water feeding member to its deepest position and then a pilot light burner is ignited. At this time, an initial opening valve holding circuit of a control circuit may output an auxiliary time until the opened valve of a first fuel valve can be kept with an electromotive force of a first thermocouple heated by a pilot burner so as to assure the opened valve of the fuel valve. If the ignition is confirmed with a flame rod within this auxiliary time, a forced valve opening holding electrical power is supplied, for a desired time. With this arrangement it is possible to make a positive ignition while keeping safety characteristics. Finally, from German patent no. 1946588 we know of a security means for the electric ignition of domestic apparatus which are heated by gas through an electromagnetic valve which controls the gas feed to the point of its combustion, the winding of the electromagnetic valve being in the manner of a transformer for the igniting means, a timer being connected in the primary circuit of the current of the magnetic valve for gas, which can be connected (jumped) thermoelectrically, and in that the spark igniting means can be control through high tension, located en the valve secondary circuit, through a flame controller by ionization, already known. The invention covers a gas appliance with the features detailed in claim 1. The dependent claims deal with further embodiments of the gas appliance according to claim 1. To allow for easier understanding, not only of the construction, but also of the correct use of the instant lighting device of the invention, a practical example of operation is provided below, just as is shown in the corresponding schematic diagram. This explanation is merely illustrative and operation is not in any way restricted to the example given. The device (1) consists of a printed circuit (2) which includes a set of pushbuttons (3) by means of which the valves controlling the flow of gas to the burner (not shown for the appliance for household use), are activated. When the device has more than one valve, or likewise, more than one burner, and as a result has various thermocouples (4), the circuit is equipped with a selector (5), so that by means of a trigger (6), a single valve may be selected for use with the corresponding supply. One the pushbutton (3) is pressed, the burner is lit by means of a spark lighter (7), and the supply of an auxiliary current is provided to the magnetic group of the valve. The supply source (8) can be used with a storage cell, and can also be connected to the circuit by an isolation transformer (9). Both the isolation transformer and the thermocouples (4) together with the spark lighter (7), are controlled by means of timers (10), and in both cases operate on transistors (11).

Claims: A gas appliance having an instant lighting device (1) with a spark lighter (7), comprising at least one burner, with at least one corresponding magnetic group of safety valves and thermocouples (4) to be heated by the flames of the burner(s) in order to allow gas to be fed to the burner(s) when heated, an electric supply source (8) with storage cell for supplying auxiliary electric current to the instant lighting device (1) and the magnetic group of safety valve(s), an isolation transformer for suppling electric current to the electric supply source (8), characterized by a printed electric circuit (2) with outlets and a timer (10) for feeding and timing the spark lighter (7) and the auxiliary current to the magnetic group of safety valve(s) and to the thermocouples (4), the said auxiliary current to be replaced by the electrical current generated by them once heated by the flame, by a trigger (6) and a selector (5) for controlling the instant lighting device (1) in order to enable where necessary the supply of gas only to one safety valve at the time so as to prevent the possibility of activating more safety valves at the same time and by the fact that the safety valve shuts off when the corresponding thermocouple cools at a temperature which corresponds to a one third energy reduction of the generated electric current. A gas appliance according to claim 1, characterized in that the timer (10) allows the supply of electric current such that the duration of the auxiliary current is greater than that of the functioning of the spark lighter (7). A gas appliance according to claim 1, characterized in that the lighting device (1) comprises a pushbutton (3) for enabling the supply of electric current to the device (3) and in that upon pressing the pushbutton (3) for supplying electrical energy to the lighting system the existance of a flame is detected through ionization, the spark lighter stops functioning and, at the same time, the timer (10), which gives auxiliary electricity to the thermocouple continues functioning during approximately 6 seconds more. A gas appliance according to claim 3, characterized in that once the thermocouple (4) is heated, if the pushbutton (3) is pressed, the printed electrical circuit (2) is not in use and does not consume energy.

Inventors: BERTOMEU MARTINEZ FRANCISCO, BERTOMEU MARTINEZ, FRANCISCO
Applicants: BERTOMEU MARTINEZ FRANCISCO, BERTOMEU MARTINEZ, FRANCISCO
Application year: 1991
Main classification: F24C3
IPC codes: F23N5, F24C3