GB2183329A - Simulated solid fuel gas fire - Google Patents

Abstract

A gas fire has a main plaque type burner (11) and a transparent or translucent e.g. glass wall (15) spaced therefrom to form a closed combustion chamber (14). A heat exchanger receives gas directly from the chamber (14) without dilution. Wall (15) supports spaced fuel simulations (24) which allow the wall (15) to be seen therebetween. The wall glows red in use and enhances the appearance of the fuel simulation. Secondary burner (23) burns lightly aerated gas in an open combustion area to look like open fire flames. The closed combustion chamber of the main burner achieves a high efficiency. The overall efficiency being a combination of this and the low efficiency achieved by the secondary burner. <IMAGE>

Description

SPECIFICATION Gas-fired heating appliance This invention relates to a gas-fired heating appliance of the kind providing a simulation of a real fire.

The invention provides a gas-fired heating appliance having a main burner, a closed combustion chamberthereforand a heatexchangerlocatedtore- ceive exhaust gases from the combustion chamber, an upperwall of said combustion chamber being formed oftransparent ortranslucent material and lying at an angle inclined to the horizontal, nonburning fuel simulation means located above said upperwall leaving spaces through which the said upperwall can be seen, and a secondary burner, providing floppy flames in an open combustion area to play among fuel simulation means.

The said main burner may be a plaque burner, lying atthesame inclined angle, the transparent wall being spaced from the upper surface of the plaque to form said combustion chamber. The combustion chamber may have an opening at its lower end for the entry of combustion air.

The appliance may have an exhaust connected to receive exhaust gases from the heat exchanger and from the secondary burnerso thatthe exhaustgases from the main burner do not mix with those from the secondary burner until afterthe heat exchanger.

A specific example of the invention is shown in the accompanying drawing which shows a diagrammatic side section through a gas fire.

The main burnerofthefirecomprisesaceramic plaque (11) having a plurality of open channels (12) through which gas flows from mixing chamber (13) to burn in combustion chamber (14). Thecombus- tion chamber (14) is closed between the uppersurface ofthe plaque and a heat-resistanttransparent glass sheet (15) spaced therefrom. The sheet and plaque are located atan angletothe horizontal of about 30 so that the combustion chamber is inclined upwardly from thefront to the back ofthe fire.Atthe back of the fi re a heat exchanger ( 16) receives the exhaustgasesfromcombustion chamber(14)and passes them along the paths indicated by arrows A until they emerge at exit (17) and enter an exhaust duct (18).

An opening (21 ) atthefrontend of combustion chamber (14) allows combustion airto enterthe chamber. It will be seen that combustion is confined in the combustion chamber and the amount of combustion air is controlled by the size of the opening (21). The exhaust gases follow the confined paths in the heat exchanger and do notemergeto be diluted until they reach exit (17). The exhaustgasesthere- fore maintain their high temperature and heat ex changetakes place underfavourabletemperature differentials. Thus a highly efficient heat output is achievedforthis part of the fire.

Convectedairheated bytheheatexchanger passes along the path indicated by arrows B and emerges into the space being heated by the fire at outlet (20).

In orderto provide the appearance of burning fuel, there is a secondary burner (23) which burns lightly aerated gas, i.e. gas just sufficiently aerated to produce floppy flames which look like those of burning coal. The burner (23) is directed backwardly and upwardly at an angle, preferably parallel to the combustion chamber(14), into an open combustion area.

A plate (25) intercepts the flame from the burner and thus causes itto spread outwardly and upwardly.

Abovethe burner (23) and alongthefrontofthefire are separate lumps of artificial coal (24), i.e. ceramic non-burning representations of coal. These hide the burner and provide spaces so that the flame from the burnerflickers between them and looks like a coal burning fire. Although only one burner (23) isshown, there may be a plurality of burners, e.g. three spaced along the front ofthe fire.

Behind plate (25), a plurality of separate coal simulations are located on the glass sheet (15). The coal simulations are separated so that areas (26) ofthe glass can be seen. For instance, it may be arranged that 25% to 60% of the glass is not covered by coal simulations. When burner (11) is a I ig ht, the surface ofthe plaque burner glows red and can be seen through the glass sheet. The actual flames in the combustion chamber also contribute to the glow.

The glass chosen is 95% transpa rent to infra-red radiation so that radiant heat from and through the sheet helps to heat the room space. Moreover, the red glow, seen between the coal simulations, looks very much like a glowing firebed.

The overall representation ofafirethereforecom- prises a combination of coal simulationsonaglo- wing red firebed with real flames atthe frontflicker- ing between coal simulations.

The exhaust gasesfrom the burner (23) follow arrow C into exhaust (18)wherethey join the exhaust gases from the heatexchanger. Thefire has an open front (27) through which the representation is viewed and through which heat is radiated. The open front means that air is entrained with the exhaust gases from burner (23) so that the exhaust gases are cooled. However, these gases are not mixed with the exhaust gases from the plaque until afterthese gases have passed through the heat exchanger. Thus the efficiency of heat transfer in the heat exchanger is not adversely affected. A partial glass canopy (30) may reduce the entrained air, butthe majority ofthe front ofthe fire is open.

The gas supply to burners (23) and (11) is controlled from manual control valve (31). This provides a numberofdifferentsettingsgiving differentgas flows to the plaque burner (11) so that different heat levels can be attained. All ofthese positions are accompanied byflowthrough the burner (823) so that the fuel simulation is maintained. There is also a low, fuel simulation, setting of control valve (31) in which the plaque burner is not operating, only valve (23) being supplied with gas. In this position the fire operates as a decorative fuel simulation, with only a very low heat output.

As described above, the plaque burner(1 1) oper- ates u nder tig htly control led conditions, so thatthe heat exchanger can effect a high local efficiency. The fuel effect burner (23) operates in open conditions producing very little heat. The overall efficiency of the fire is a combination ofthesetwo efficiencies, the fuel effect burner reducing the attained overall efficiency. However, it is still possible to achieve efficiencies of the order of 66% on settings otherthan the low, fuel simulation only, setting. By locating the high efficiency closed burner to form the base of a fuel effect and making one wall thereof transparent, it has proved possible to make a high efficiency burner part of a simulation of a real fire. The inevitable high temperature achieved in the gas combustion chamber is thus used to provide a glowforthe fuel simulation.

Although coal simulations have been described above,the simulations could be of logs orcoke.

Claims (12)

1. A gas-fired heating appliance having a main burner means, a closed combustion chamber therefor, and a heat exchanger located to receive ex haust gases from the combustion chamber, an upper wall of said combustion chamber being formed of transparent ortranslucent material and lying at an angle inclined to the horizontal, non-burning fuel simulation means located on or above said upper wall leaving spacesthrough which thesaid upper wall can be seen, and a secondary burner meansfor providing floppy flames in another, open, combustion area to playaboutthefuel simulation means.

2. A heating appliance as claimed in claim 1, wherein said main burner means is a plaque burner, the transparent ortranslucent wall being spaced from the upper surface ofthe plaque to form therewith said closed combustion chamber.

3. A heating appliance as claimed in claim 1 or claim 2, wherein said closed combustion chamber has an opening at one end forthe entry of combus- tion air and is connected atthe other end to the heat exchanger.

4. A heating appliance as claimed in claim 2 or claim 3,wherein said plaque and saidwall are both inclined at an angle of about 30 to the horizontal.

5. Aheating appliance as claimed in any of claims 1 to 4, wherein said secondary burner means is located atthefrontofthe appliance and directed backwardly and upwardly.

6. A heating appliance as claimed in claimS, having a plate positioned in the flame path of said sec ondary burner means so asto interceptflamesand cause them to spread.

7. A heating appliance as claimed in claim 6, wherein said fuel simulation means includes a plurality of separate simulations located above the secondary burner means along the front ofthe appliance.

8. A heating appliance as claimed in any of claims 1 to 7, wherein said fuel simulation means inclues a plurality of separate simulations located on said wall, leaving 25% - 60% ofthe wall surface uncovered.

9. Aheating appliance as claimed in any of claims Sto 7, wherein the majority of the front ofthe fire is open allowing airto be supplied to said secondary burner means.

10. A heating appliance as claimed in any of claims 1 to 9, having an exhaust duct connected to receive exhaust gases from the heat exchanger and from the secondary burner means so that the exhaust gases from the main burner means do not mix with those from the secondary burner means until after their passage through the heat exchanger.

11. A heating appliance as claimed in any of claims 1 to 10, wherein said wall is formed of heatresistant glass.

12. A heating appliance substantially as described hereinbefore with reference to the accompanying drawing.