Smoothing iron

Abstract

 The invention relates to an iron comprising a metal base plate 6 which is heated by the combustion of a gaseous hydrocarbon fuel on a catalyst 9. The catalyst is supplied from a fuel reservoir 12 by means of a gas supply pipe 10, air being drawn in at 15 to provide a stiochiometric mixture. Supply of gas is controlled by a valve 13 in dependence on a thermostat 17 in the catalyst.

Description

[0001] This invention relates to a smoothing iron.

[0002] Smoothing irons (referred to herein simply as irons) are a well used household item. The old fashioned type of iron is the flat iron which is made of solid metal and is intended to be heated indirectly, for example on a gas stove. This type of iron has obvious disadvantages and has now largely been superceded by the electrically heated iron which requires direct connection to a mains electricity supply. Such irons generally comprise a heating element situated in a metal base and are provided with a control for varying the heat. The need for direct connection to an electricity supply is a disadvantage of this type of iron and it would be desirable to provide an iron which is capable of operating independently of an electricity supply. In addition, an iron without an electric cable attached would be more convenient to use.

[0003] Attempts have been made to develop irons with their own heating means which do not rely on a mains electricity supply. Such irons have generally used a gas flame to generate the necessary heat and reference can be made in this connection to British Patent Specifications 2077771A and 2128641A. Such irons have not proved particularly successful commercially and the use of an open flame for heating the iron has dangers in the domestic environment.

[0004] The present invention provides an iron comprising a metal base plate which base plate is heated by the catalytic combustion of a fuel.

[0005] Catalytic heating has the advantage that the iron can be used in environments where there is no mains electricity supply. This form of heating is capable of bringing the base plate to the desired temperature in an adequate time and it allows an iron to be made which is quicker in responding to changes in the temperature control.

[0006] The fact that there is no electric cable makes the iron easier to use and more aesthetically pleasing. The fact that the heating does not rely on an open flame makes the iron more acceptable for use in a domestic environment than known gas irons.

[0007] The iron according to the invention generally comprises a metal base plate, a catalyst for the combustion of a gaseous hydrocarbon fuel, fuel reservoir, means for supplying fuel from the reservoir to the catalyst and a valve for regulating supply of fuel to the catalyst, the base plate being capable of being heated by combustion of the fuel on the catalyst.

[0008] The combustion of the gaseous hydrocarbon fuel generally takes place in a substantially closed chamber. A mixture of fuel and air (generally in stoichiometric proportions) is fed to the chamber and is distributed over the catalyst. Ignition means are provided to initiate the reaction of the fuel with the oxygen in the air on the catalyst. Although the chamber is substantially closed, sufficient openings are provided to allow combustion products to escape. The iron also comprises a reservoir for fuel which is usually stored therein in liquid form. A valve is provided for regulating the supply of fuel and means are provided for introducing the necessary amount of air into the fuel and for supplying the fuel/air mixture to the catalyst. The valve will generally be thermostatically controlled by a thermostat located in the catalyst so that the desired temperature can be maintained. Means will also be generally provided for switching off the fuel supply completely when the iron is not in use.

[0009] The fuel is preferably a hydrocarbon which is gaseous under normal condition but which can readily be liquified under pressure. The most preferred fuel is isobutane since supplies of this fuel in liquid form are already available domestically for use in cigarette lighters. Any catalyst for the reaction of the fuel with oxygen can be used, for example a platinum group metal, preferably platinum itself. The catalyst will generally be applied to a support such as mineral wool, for example silica wool.

[0010] The ignition means for initiating the reaction on the catalyst between the fuel and the oxygen in the air is preferably a piezo electric device generating a spark when a starter control is actuated by the user. Alternatively, it is possible to use a metallic wire (e.g. platinum wire) which is heated by an electric current from a battery or even a flint and wheel. The metal base plate of the iron may be of a heavy construct­ion which is designed to retain heat as in most electrically heated irons. Alternatively the metal base plate can be of a much lighter construction, for example of aluminium, since catalytic heating is adequate to maintain the desired temperature of the base plate in use and consequently there is no need for the plate to retain heat.

[0011] The invention will now be described in more detail

[0012] The invention will now be described in more detail with reference to the accompanying drawings in which:

Figure 1 is a vertical cross-section of an iron according to the invention;

Figure 2 is a vertical cross-section in a plane at right angles to the section of Figure 1; and

Figure 3 is a horizontal cross-section through the base plate of the iron of Figure 1.

[0013] The iron shown in the drawings comprises a cover moulding 1, a front moulding 2 and a base moulding 3. The cover and front mouldings may be made of a thermo­plastic plastics material such as nylon and the base moulding may be made of an insulating material such as bakelite. The base moulding 3 is fixed to a steel cover plate 4 by means of a screw 5 (Figure 2) and the cover plate is itself attached to a die cast aluminium base plate 6. The base plate is provided with ribs 7 surrounding and in heat exchange relationship with the catalytic heating means.

[0014] the base plate is relatively light weight in construction and can be kept supplied with heat by the catalytic heating means at the same rate as heat is withdrawn when the iron is in use.

[0015] The catalytic heating means comprises a stainless steel gauze 8 containing catalytic wool 9. A stoichiometric mixture of fuel (e.g. isobutane) and air is supplied via a fuel supply pipe 10 to a gas distributor 11. The gas distributor ensures an even supply of gas/air mixture and thus an even reaction on the surface of the catalyst. A combustion reaction takes place on the surface of the catalyst in a substantially enclosed environment although small vents 16 (Figure 3) are provided to allow for escape of exhaust gases. These vent the area where combustion takes place to the main body of the iron. The design of the area where combustion takes place should provide a slight pressure drop across the catalyst to assist uniform distribution of the fuel/air mixture and assist the combustion reaction.

[0016] The fuel supply pipe 10, which may be of silicon or brass, runs from a fuel tank 12 to the gas distributor and the gas supply from the tank to the pipe is controlled by a valve 13. The fuel is present in the tank in liquid form and supply to the valve is assisted by a wick 14 made of compressed fibres. The wick is crimped into an aluminium tube 24 having a small aperture which produces a pressure drop such that the fuel is converted from the liquid phase in the fuel tank to the gaseous phase in the fuel supply pipe. The fuel passes through a venturi throat 15 which is provided with small holes to allow air to be drawn in, the size of the holes being such that a stoichiometric mixture of gas and air is obtained in the tube.

[0017] The valve 13 is controlled by a thermostat in the form of a bi-metallic strip 17 which runs through the catalyst. The bi-metallic strip is linked to the valve by a linkage 18 and closes the valve when the desired temperature in the catalyst has been achieved. The temperature at which the thermostat closes the valve can be adjusted by means of a temperature controller in the form of a ring 19 which meshes with and activates a toothed wheel 25. The toothed wheel in turn rotates a linkage 20 operating a screw 21 which alters the point at which the thermostat closes the valve. A sliding on-off switch 26 is also provided which, in the off position, prevents the thermostat from opening the valve 13.

[0018] Combustion of the gas/air mixture on the catalyst is initiated by a piezo electric starter 27 activated by a starter button 28 which generates a spark in the vicinity of the catalyst.

Claims

1. An iron comprising a metal base plate, which base plate is heated by the catalytic combustion of a fuel.

2. An iron comprising a metal base plate, a catalyst for the combustion of a gaseous hydrocarbon fuel, a fuel reservoir, means for supplying fuel from the reservoir to the catalyst and a valve for regulating supply of fuel to the catalyst, the base plate being capable of being heated by combustion of the fuel on the catalyst.

3. An iron as claimed in claim 2 adapted to use isobutane as fuel.

4. An iron as claimed in claim 2 or 3, further comprising ignition means for initiating the reaction between the fuel and oxygen.

5. An iron as claimed in any of claims 2 to 4 wherein the valve is controlled by a thermostat in dependence on the temperature of the catalyst.

6. An iron substantially as herein before described with particular reference to the accompanying drawings.

Drawing