EP0298913B1 - Ignition device for fuels - Google Patents

Abstract

The device comprises an upper part (1) including a combustion chamber (5) preceded by an air/gas mixing device (6). The lower part comprises a liquid gas reservoir (15), said reservoir being removable together with its injector (18). When replacing the empty reservoir with a filled one, the user benefits from an injector (18) in perfectly clean condition.

Description

Apparatuses for igniting combustible materials are already known, comprising a body, a removable tank of liquefied gas, this tank being provided with a valve controlling the passage of gas to a burner carried by the body, the latter comprising means for ignition of the gas reaching the burner and a control member for these ignition means, the burner being of the type comprising an air-gas mixer followed by a combustion chamber with air intake passages to create a fuel-oxidizer mixture. Among these known devices, there may be mentioned the lighter described in Peterson USA patent No. 2,482,794.

These devices require small gas flows, a few grams per hour, as well as injection nozzles having holes generally less than a tenth of a millimeter. In some cases these holes may have a dimension of a few thousandths of a millimeter. The nozzles are generally formed by metal membranes a few hundredths of a millimeter thick, in which a hole of desired size is made, either by cutting or by laser beam drilling. Sometimes watch stones are also used. It is obvious that holes of such small dimensions are easily subject to plugging, either by solid particles or by low volatile residues contained in the gas. In most cases, the tank of these devices includes a filling valve which can be connected to the spout of a refill tank of a type widely marketed at present. Most of these devices include a device for vaporizing liquefied gas, consisting of a relatively flexible, compressed porous body, limiting the flow of gas. This regulator tends to clog if the compressed gas used contains low volatile fractions which remain trapped in the porous mass. If the user chooses a gas containing too large a quantity of non-volatile fractions, the device is quickly out of use either as a result of plugging of the nozzle holes injection, or as a result of clogging of the regulator, which generally requires a return of the device to the repair service.

The object of the present invention is to remedy these drawbacks.

To this end, the ignition device according to the present invention is characterized in that the valve of the removable tank is shaped at its end to constitute an injector for introducing the combustible gas into the chamber, this injector being arranged, in the position of operation, facing a gas supply duct to the chamber, without penetrating into it, an annular space being formed between the injector and the internal wall of the supply duct, the valve comprising a compensation device the effect of temperature on gas flow.

Another embodiment of the apparatus for carrying out the invention, where the injector, in the operating position, partially penetrates into the supply duct, is produced by claim 5.

• La Fig. 1 est une vue en coupe verticale de cette forme d'exécution.
• La Fig. 2 est une vue en coupe à plus grande échelle d'une partie de l'appareil.

The accompanying drawing shows schematically and by way of example an embodiment of the apparatus forming the object of the invention.

• Fig. 1 is a vertical sectional view of this embodiment.
• Fig. 2 is an enlarged sectional view of part of the apparatus.

The device shown can be used as a lighter or as an igniter. It comprises an upper part 1 carrying a cover 2, articulated on a pivot 3 and subjected to the action of a spring device not shown as known in itself, for resiliently holding the cover in the closed position and respectively in the open position .

The upper part 1 also carries a combustion chamber 5 comprising an air-gas mixer 6, fixed at its base.

This air-gas mixer comprises a supply duct 7 for the gas, this duct being of generally conical shape and having two lateral openings 8 forming additional air inlets.

The upper part 1 also supports an electric ignition device 9 of the piezoelectric type which can be actuated by push button 10. The piezoelectric ignition devices being well known in themselves, it will not be given detailed description. The ignition voltage is brought by a conductor 11 to an electrode 12 disposed in the chamber 5. The spark ensuring the ignition bursts between this electrode 12 and a part of the chamber 5, for example the finned diffuser 14 which ends the gas supply pipe.

The apparatus also comprises a reservoir 15 containing liquefied combustible gas such as butane or propane or a mixture of these. This reservoir 15 is retained by a cover 16 which engages in a notch on the base of the upper part 1. This reservoir 15 is provided with an evaporator 17 for liquefied gas, which will be described in more detail with reference to FIG. . 2. This evaporator carries an injector 18 located opposite the supply duct 7.

With reference to FIG. 2 we see that the injector 18 ends with a part 19 having a calibrated orifice, this part being constituted by a timepiece pierced to form a nozzle. The drilling of the stone is of a very small diameter, generally of the order of a few hundredths of a millimeter. The injector 18 is mobile and has, in a manner known per se, a longitudinal bore 20, communicating with a lateral bore 21. This injector is subjected to the action of a spring 22 and carries at its base a shutter element 23, made of elastomer, which is applied against a seat 24.

When the push button 10 is actuated, a mobile part 25 of the piezoelectric device 9 is lowered and pushes with the aid of a tab 26 the end of a rocking lever 27, the other end 28 of which is fork-shaped and engaged under a flange 29 of the injector 18. The lever 27 then takes a horizontal position and its fork 28 lifts the injector 18, in order to open the valve formed by the shutter member 23 and the seat 24, thus allowing the injection of gas into the mixer.

Indicated in dashed lines 18 is the raised position of the injector 18 and it can be seen that the latter partially penetrates into the supply duct 7, so as to leave free an annular space 30 which allows a first suction of air caused by the liquefied gas escaping through the orifice of the timepiece 19. After this first mixing between the gas and the air, the flow exiting through the upper end of the duct 7 causes additional air to be drawn in by the openings 8 before the mixture enters the chamber 5. The fuel and the oxidizer must arrive in this chamber in a well-defined mixing ratio so that the combustion takes place inside the chamber and thus obtain a flame having a excellent wind resistance.

To obtain the desired precision of the fuel / oxidant ratio, it is necessary that the flow rate of the combustible gas is stable and protected from variations in the vapor pressure of the liquefied gas. As is known, the vapor pressure is strongly influenced by temperature. It is therefore advantageous to provide a device for compensating for the effect of temperature, for example of the type described in French patent No. 1,481,240.

In a device of this type, the liquid gas penetrates through an orifice 31 of the diffuser 17, to reach a porous tablet 32 provided just under the seat 24. This tablet is compressed by a part 33, housed in the diffuser 17, this part 33 having a coefficient of expansion greater than that of the metal tube constituting the diffuser 17. This arrangement makes it possible to increase the pressure on the pellet 32 when the temperature of the liquefied gas in the reservoir 15 increases, this in order to compensate for the increase in the flow rate of gas which is due to the increase in the evaporation pressure of the gas with temperature.

Thanks to the construction provided, the user can remove the reservoir 15, when it is empty or in the event of a malfunction, by removing the cover 16 to replace it with a new reservoir whose calibrated orifice of the injector is in in immaculate condition, which constantly ensures perfect operation of the device.

The injector 18 could, in the operating position, come opposite the supply duct 7 without partially penetrating it. This duct 7 does not necessarily have to be conical and could very well be of cylindrical shape for example. Similarly, the admission of additional air through the side openings 8 is not essential and these openings could be omitted.

Claims (5)

1. Appliance for igniting flammable substances, comprising a body, a removable container of liquefied gas, this container being fitted with a valve controlling the passage of the gas to a burner carried by the body, the latter comprising means for igniting the gas arriving at the burner and a device for controlling these means of ignition, the burner being of the type comprising an air-gas mixer with a passage for admitting air to create a fuel-oxidant mixture, followed by a combustion chamber, characterised in that the valve on the removable container is shaped at its end to form an injector for introducing the flammable gas into the chamber, this injector being arranged, in its operating position, opposite a pipe for feeding the gas to the chamber without entering inside the pipe, an annular space being provided between the injector and the internal wall of the feed pipe, the valve comprising a device for compensating for the effect of temperature on the gas flow.

2. Appliance according to claim 1, characterised in that the injector comprises a calibrated passage, this passage being formed by a drilling in a watchmaker's jewel.

3. Appliance according to claim 1 or 2, characterised in that the pipe for feeding the gas to the combustion chamber is conical in shape overall.

4. Appliance according to claim 3, characterised in that the feed pipe comprises at least one side air inlet opening, situated downstream of the portion of its conical part which has the smallest cross section.

5. Appliance for igniting flammable substances, comprising a body, a removable container of liquefied gas, this container being fitted with a valve controlling the passage of the gas to a burner carried by the body, the latter comprising means for igniting the gas arriving at the burner and a device for controlling these means of ignition, the burner being of the type comprising an air-gas mixer with a passage for admitting air to create a fuel-oxidant mixture, followed by a combustion chamber, characterised in that the pipe for feeding the gas to the combustion chamber is conical in shape overall and comprises at least one side air inlet opening, situated downstream of the portion of its conical part which has the smallest cross section, in that the valve on the removable container is shaped at its end to form an injector being arranged, in its operating position, partially in the pipe for feeding the gas to the chamber, an annular space being provided between the injector and the internal wall of the feed pipe, the valve comprising a device for compensating for the effect of temperature on the gas flow.

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