EP0790467A1 - Safety means for use with a gas heating or gas cooking appliance - Google Patents

Abstract

The gas cooker (1) includes hot plates heated by gas, with a connection to a gas supply distribution system or a reservoir providing a store of bottled gas connected via a flexible supply pipe (3). With the apparatus there is a detector sensing the presence of a flame (12), associated with at least one burner (2). An electrically operated safety valve (13) is connected to the cooker before the connection to the flexible hose (5). In the absence of a flame acting on the detector, particularly after a predetermined attempts at starting the burner, the electronic control system forces the closure of the safety valve (13). A protective sleeve (16) with space surrounding the flexible pipe (5) encloses the pipe between the safety valve and the burners.

Description

The present invention relates to a protection device, intended to reinforce the safety of a cooking or heating appliance, in particular of a domestic appliance, using gas supplied by a distribution network, by a tank or by a gas cylinder. This protective device makes it possible in particular to cut off the gas supply to the appliance, in the event of detection of a gas leak or other malfunction of the appliance or of a set of appliances, thanks to an automatic full.

A gas cooking or heating appliance is usually supplied with gas, from a fixed gas supply fitting situated in the place where the appliance is installed, by means of a flexible pipe. In known manner, such an appliance may comprise, associated with its gas burner (s), means capable of detecting the presence of a flame, and of controlling the closing of a safety valve integrated into the appliance, in the event when there is no flame when the appliance is placed in the on position.

By way of example of this state of the art, reference may be made to German patent application No. 1962708, to which corresponds French patent No. 1598786, and to German patent No. 4003799. In particular, the application German Patent No. 1962708, serving as a basis for the preamble of claim 1, describes a safety device for a gas burner, which automatically makes repeated attempts to relight, before controlling the stopping of the gas supply to the burner . However, this document does not provide any details regarding the location of the safety valve. As for the German patent N ° 4003799, this provides for a safety solenoid valve placed on the gas inlet, inside the cooking appliance itself.

German patent application No. 2832196 describes a gas cooking appliance, with a solenoid valve for safety placed at an intermediate point of its gas supply pipe. However, this document does not relate to a safety device reacting directly to an absence of flame, whatever the cause; this is a device that detects only the overflow of water contained in a cooking utensil. This device therefore does not belong to the genre concerned by the present invention, and cannot ensure safety for all types of faults.

Thus, certain known devices can provide suitable security in the event of a fault occurring inside the device itself, for example if the igniter is defective. By cons, as is easily understood, these safety devices are unable to provide protection in the event of faults occurring upstream of the device, in particular faults affecting the flexible gas supply pipe of the device , for example when this gas pipe accidentally came out of the appliance's supply pipe; in such a case, in fact, the closing of a safety valve incorporated in the device cannot prevent the escape of gas through the pipe which is "disconnected". This results in quite a number of accidents, which are often very serious.

The present invention aims to eliminate these drawbacks by providing an improved protection device for a gas cooking or heating appliance, the proposed device ensuring total security by effectively cutting off the gas supply, whatever the location. where the fault is located, including in the case of a fault external to the appliance, in particular a fault touching at any point the flexible gas supply pipe.

• sur l'appareil lui-même, au moins un détecteur de présence de flamme associé à au moins un brûleur,
• sur l'alimentation en gaz de l'appareil, une vanne de sécurité à commande électrique, et
• une électronique de commande reliée fonctionnellement d'une part au ou à chaque détecteur de présence de flamme, et d'autre part à la vanne de sécurité, pour commander la fermeture de cette vanne de sécurité en cas d'absence de flamme, l'électronique de commande étant de préférence conçue de manière à tenter de rallumer le brûleur un nombre de fois N prédéfini en cas d'absence de flamme constatée par le détecteur, et à commander la fermeture de la vanne de sécurité, si la flamme reste absente à l'issue des N tentatives d'allumage,

ce dispositif étant caractérisé en ce que la vanne de sécurité est placée en amont de l'appareil, au départ du tuyau d'alimentation en gaz, c'est-à-dire au niveau du raccordement au réseau de distribution de gaz, au réservoir ou à la bouteille de gaz.To this end, the subject of the invention is a protection device for a gas cooking or heating appliance, connected to a distribution network of gas, to a gas tank or cylinder through a flexible gas supply hose, comprising:

• on the device itself, at least one flame presence detector associated with at least one burner,
• on the gas supply to the appliance, an electrically operated safety valve, and
• control electronics functionally connected on the one hand to or to each flame presence detector, and on the other hand to the safety valve, for controlling the closing of this safety valve in the event of absence of flame, the control electronics preferably being designed so as to attempt to relight the burner a predefined number of times N in the event of the absence of flame detected by the detector, and to control the closing of the safety valve, if the flame remains absent at the outcome of the N ignition attempts,

this device being characterized in that the safety valve is placed upstream of the appliance, from the gas supply pipe, that is to say at the connection to the gas distribution network, to the tank or the gas cylinder.

Advantageously, the control electronics integrated into the device is connected to the safety valve, placed at the start of the gas supply pipe, by electrically conductive wires for supplying and controlling this valve which pass through a space. located between the gas supply pipe proper and a protective sheath surrounding said gas supply pipe. The safety valve is thus supplied electrically, and controlled, from the gas cooking or heating appliance itself.

In a variant, this safety valve, placed at the point of connection to the gas distribution network, to the tank or to the gas cylinder, can also have a power supply separate from that of the appliance, which may in particular be advantageous in the case of a safety valve common to several gas appliances. The safety valve can be optionally remote-controlled, the connection by electrical wires from the appliance along the gas supply pipe being replaceable by a transmission of control signals using the existing electrical supply network at the place where the device is installed, and thus superimposed on the current of the sector, or even by a wireless transmission (hertzian or infrared)

In all cases, a protection device is obtained, which automatically closes a safety valve placed on the gas supply connection in the place where the appliance is installed, when an absence of persistent flame is observed. , and this whatever the cause: absence of gas, defective igniter, gas pipe accidentally taken out of the supply pipe of the device. In particular, in the latter case, the position of the safety valve allows it to prevent any gas from entering the supply pipe, so that the fault (gas leak) having caused the intervention of the protective device is radically removed. It is therefore understood that the device object of the invention ensures, in such a case, total security.

In any case, the invention will be better understood with the aid of the description which follows, with reference to the appended diagrammatic drawing representing, by way of example, an embodiment of this protective device for a cooking or gas heating.

The only figure in the drawing shows, in perspective, a gas cooking appliance equipped with the protection device according to the present invention.

More particularly, this figure represents, very schematically, the hob 1 of a gas stove, or electric / gas combination, comprising in the example considered at least two gas burners 2.

The stove is supplied with gas supplied here by a gas distribution network 3, comprising a gas supply connection 4 located at the place where the cooking appliance is installed. In a generally known manner, a flexible gas supply pipe 5 connects the connector 4 to the appliance itself. The supply of gas to the various burners 2 takes place via internal conduits 6 and is controlled by means of regulating solenoid valves 7, which are in particular cycled solenoid valves.

The cooking appliance also comprises keys 8, or other similar control buttons, connected to control electronics 9, itself electrically connected by conductive wires 10 and 11 to the regulating solenoid valves 7, as well as to igniters. 12 associated with the different gas burners 2. In each igniter 12 is incorporated a flame detector.

According to the invention, an electrically operated safety valve 13 is placed, inside a housing 14, at the start of the gas supply pipe 5, that is to say at the level of the connection gas supply 4. The safety valve 13 is electrically connected to the control electronics 9 by conducting wires 15 which pass into a space 16 located between the gas supply pipe 5 proper and a protective sheath 17 surrounding this supply pipe 5, over its entire length from the housing 14 to the cooking appliance. As regards the safety valve 13, it can be a normally closed solenoid valve, comprising a needle pointed by a spring towards an annular seat, the electrical supply of the coil of this solenoid valve being necessary to control and maintain its opening.

During normal operation of this cooking appliance, the safety valve 13 is kept in position opened. The normal operating condition is noted, for the or each gas burner 2 put into service, by the associated flame detector located at 12, cooperating with the control electronics 9.

If a flame detector located at 12 detects an absence of flame, while the corresponding burner 2 has been placed in the on position by pressing the corresponding control button 8, the system attempts to relight this burner 2 a number of times N predefined. If after N re-ignition attempts, the detector located at 12 observes the persistence of the absence of flame, the control electronics 9 causes, through the electrical wires 15, the closing of the safety valve 13. Any arrival gas to the stove is interrupted.

In particular, in the case of an absence of flame resulting from a gas leak at the flexible gas supply pipe 5, the closing of the safety valve 13 located at the starting point of this pipe 5 makes it possible to immediately remove this leak, thus ensuring total protection.

In view of the above, the invention is more particularly applicable to a gas cooking or heating appliance, the entire operation of which is managed automatically, by control electronics 9 combined with the use of solenoid valves. 7.

It goes without saying that the invention is not limited to the only embodiment of this protective device for a gas cooking or heating appliance which has been described above, by way of example; it embraces, in the content, all the variants and application falling within the scope of the claims. In particular, one would not depart from the scope of the invention by modifying the internal structure of the safety valve, or by applying the same device to any gas appliance, regardless of the number of gas burners, and regardless of the source of gas: supply network, gas tank or bottle.

Claims (3)

Protective device for a gas cooking or heating appliance (1), connected to a gas distribution network (3), to a gas tank or bottle via a flexible supply hose gas (5), the device comprising: - on the device (1) itself, at least one flame presence detector (12) associated with at least one burner (2), - on the gas supply (5) to the appliance, an electrically operated safety valve (13), and - control electronics (9) functionally connected on the one hand (at 11) to or each flame detector (12), and on the other hand (at 15) to the safety valve (13), for control the closing of this safety valve (13) in the absence of a flame, the control electronics (9) being preferably designed so as to attempt to relight the burner (2) a predefined number of times N in the event of absence of flame noted by the detector (12), and to command the closing of the safety valve (13), if the flame remains absent at the end of the N ignition attempts, characterized in that the valve safety (13) is placed upstream of the appliance (1), from the gas supply pipe (5), that is to say at the connection (4) to the gas distribution network ( 3), to the gas tank or cylinder. Protection device for a gas cooking or heating appliance, according to claim 1, characterized in that the control electronics (9) integrated into the appliance (1) is connected to the safety valve (13), placed from the gas supply pipe (5), by electrically conductive wires (15) for supplying and controlling this valve (13) which pass into a space (16) located between the gas supply pipe (5) proper and a sheath of protection (17) surrounding said gas supply pipe (5). Protective device for a gas cooking or heating appliance according to claim 1, characterized in that the safety valve (13), placed at the start of the gas supply pipe (5), has a separate electrical supply from that of the appliance (1).

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