GB2185100A - Simulated solid fuel gas fire - Google Patents

Abstract

A solid fuel effect gas fire (10) comprises a chamber (13) into which a gas injector (14) entrains air to form a mixture which can permeate through a perforated ceramic radiant plaque (20) which is disposed above the chamber (13). A ceramic fibre spacing blanket (23) and blocks (24,25) space imitation coal or other solid fuel pieces (26) from the plaque (20) so that combustion of the mixture can take place in the spaces between the pieces (26) and between the pieces (26) and the plaque (20). The plaque (20) glows and serves to radiate heat to supplement the heat of the burning gas/air mixture. <IMAGE>

Description

SPECIFICATION Fire This invention relates to fires and in particular to fires using gas fuel but having the appearance of a coal or other solid fuel fire.

Coal-effect gas fires are already known. One type of such fire comprises a steel tray on which a ring burner is disposed. The burner and tray are covered in sand and imitation coal is placed on top ofthe sand. The neat gas passes through the sand and is ignited in the air spaces between the imitation coal pieces. To improve the efficiency of such a fire an aperture has been provided in the tray centrally of the burnersothatair may be drawn upwardlytherethrough to mix with the gas passing through the sand, thereby aiding combustion. Such an arrangement provides a burning gemperature in the region of 800"C. A second type of coal-effect gas fire has a vertical gas injector beneath a vertical tube, the gas entraining airfrom around the injector into the tube.

A cover above the open top of the tube deflects the airgas mixture laterally into an annularspacewhich is filled with mica. The mica also extends abovethe cover, and allows the air-gas mixture to permeate therethrough to imitation coal disposed above it.

Again the air-gas mixture is burned in the spaces between the pieces of imitation coal. Such an arrangement can give a burning temperature in the region of 1000 C.

Athirdtype of such a fire has gas and entrained air injected into an improved gas/air mixing chamber, the chamber having apertures in the top and front thereof through which the mixture passes to be ignited in spaces between pieces of imitation coal disposed above and in front of the mixing chamber.

Such an arrangement can produce a burning tem peratureofabout1080 C. Forsimiiargasinputsthe abovementioned fires produce approximately 1 kw, 1 to 2kw and 21/2 kw heat output respectively.

It is an object of the present invention to provide a fire of the fuel-effect, gas-burning type in which the combustion process is more efficient than with the known fire arrangements.

The invention provides a solid fuel-effect gas fire comprising a chamber,a gas injectoroperableto in- jectgas into said chamberandto entrain airfrom adjacent said injector to pass into said chamberwith said injected gas to be mixed therewith in said chamber, the upper surface of said chambercomprising a perforated radiant plaque through which said mixture may pass, and a plurality of pieces of non-combustible imitation fuel disposed above said chamber providing spaces therebetween in which combustion of said mixture may be effected.

Preferably said plaque is a ceramic radiant plaque having a plurality of apertures therein disposed substantially uniformly spaced over the surface thereof.

Preferably spacing means of a non-combustible material is located adjacent said plaque, thereby providing that said imitation fuel pieces are spaced from said plaque to form a combustion space therebetween. Said spacing means may have apertures therethrough through which said mixture and/or air may pass. The fire may also comprise heat exchan germeans comprising at leastonetube around which combustion gases may flow and through which air may pass to be heated by said combustion gases.

Embodiments of fuel-effect gas fire in accordance with the invention will now be described with refer ence to the accompanying drawings in which Figure lisa cross-sectional side elevation of one embodiment of assembled fire, Figures 2 and 3 are plan views of the chamber of Figure 1 with the plaque removed, and in situ respectiveiy, Figure 4 is a plan view of the assembled fire of Figure 1, Figure5is an exploded view of a second embodiment, Figures 6and 7are plan and side views of the embodiment of Figure 5 without coals, and with coals respectively, Figures 8and 9 are side views of the flame control mechanism of Figure 5 in the offand on positions respectively, and Figures 10 and 11 are rear and side views re- spectivelyofa heat exchanger.

Referring now to Figures 1 to 4there is shown a fire 10 which is shown as being rectangular in plan view for convenience but in practice would be of planform to suit the shape ofthefire recess 11 in a building.

The fire 10 comprises a cast iron grate 12 in which a cast iron chamber or burner box 13 is disposed.A gas injector 14 is mounted on the side ofthe burner box 13to injectgasfrom a supply (not shown) into a venturitube 15 extending centrally across the i n- terior 16 ofthe burner box 13. The entrance 17 ofthe tube 15 is spaced from the gas injector 14sothatthe gas injected into the tube 15 entrains airfrom adja centthe injector 14.The other end ofthetube 15 is open and above it isa deflector plate 18. Bythis means the air and gas are mixed in the tube 15 and in the interior 16 of the burner box 13 to form a readily combustible mixture. Resting on a peripheral lip 19 provided around the burner box 13 is a perforated ceramic radiant plaque 20.

The plaque 20 rests in a substantially horizontal position and the air/gas mixture can pass upwardly through the apertures 21 provided therein. The apertures 21 are disposed substantially uniformly spaced overthe surface ofthe plaque 20 and the uppersurface ofthe plaque 20 is of multi-pyramidal shapeto increase its surface area and hence its heat radiating abilities.Asuitable radiant piaqueforthis purpose is a Tennaglo (Registered Trade Mark) ceramic radiant such as is described in U.K. Patent 1,436,842.

Around the rim 22 of the burner box 13 is placed a ceramic fibre blanket 23 which supports at the rear of the fire 10 two ceramic fibre board pieces or blocks 24,25. Pieces 26 of imitation coal are then placed in a rectangular disposition so asto rest on or bridge the gap between the blanket 23 and the blocks 24,25, as shown in Figure 1 and in dashed lines in Figure 4.

There are apertures 27 in the lower block 24and an underside cavity 28 communicating with apertures 29 in the upper block 25. By this means the air/gas mixture can distribute itself throughoutthe full ex tent of the fire as shown bythe arrows in Figure 1. In addition furtherairis drawn into the underside cavity 28 from the rear of block 24 as shown by the arrowA in Figure 1. This enables primary combustion of the air/gas mixtureto occuras itisemittedfromthe plaque 20, thereby causing the plaque surface to glow and radiate heat therefrom, and secondary combustion to occur in the spaces between the pieces of imitation coal 26 as more air is drawn in through the underside recess 28.In this way burning temperatures of approximately 1 250" can be obtained. However due to the plaque 20 being beneath the combustion area, and not above it as is generally the case with radiant plaques which are mounted in a vertical or near vertical position, and due to the cooling effectofthe large quantities of air being drawn into the fire, the plaque 20 can be maintained at its design temperature of approximately 1000 C.

It is to be noted thatthe plaque 20 is not secured in place on the lip 19 ofthe burner box 13,therebyallo- wing itto expand and contract freely and reducing the risk offracture.

Referring now to Figures 5 to 7 there is shown a fire 50 which is similar in many respectstothefire 10 previously described, and corresponding parts in the two embodiments are identified by the same reference numerals. In the case of fire 50 it is shaped in plan viewto suitthe shape of a fire recess 11 in a building. Thefire 50 comprises a cast-iron grate 12 and burner box 13, a gas injector 14, venturi tube 15, deflector plate 18 and perforated ceramic radiant plaque 20 resting on a lip 19 ofthe burner box 13, as with the previous embodiment.Also as with the pre vious embodiment a ceramic fibre blanket 23 is loc ated around the rim 22 oftheburnerbox 13.Atthe rearand sides of thefire 50 and supported on the blanket 23 are a ceramic insulating back brick 51 and sidecheeks 52,the back brick 51 being spaced from the rear ofthe fire recess 11 by a blanket spacer 53.

Also located at rearof thefire 50 and supported by the blanket 23 is a matrix 54 of ceramic fibre board having apertures 55 extending therethrough.Asup port bar 56 rests upon the matrix 54 atthe rear thereof. Beneath the grate 12 atthefront of the fire 50 is a gas control 57 which comprises a rotary knob controlling a valve (not shown) which is movable in the gas supply pipe (not shown) between gas cut-off and gas fully on positions. Aflame control lever 58 is also provided beneath the grate 12 and is operable in the off position as shown in Figure 8 to aliow ful l, smooth fiow of gas from the injector 14 and airfrom its surroundings into the venturi tube 15 and interior 16 ofthe burner box 13.A high efficiency flame is therebyobtained. Byturningtheflamecontrol lever 58 to the on position as shown in Figure 9, the flow of gas from the injector 14 is interrupted by the deflec tor61 so that a turbulentflow of air/gas mixture occurs in the venturi tube 15. Although the air supply is not restricted by this means, a luminous flame is obtained.

To complete the fire a plurality ofsmall finger imitation coals or other solid fuel pieces. e.g. logs 59 are placed on the front ofthe blanket 23 and longerfinger imitation coals, logs orthe like 60 are placed to bridgethe matrix 54 and the small fuel pieces 59. A second set of larger finger imitation fuel pieces 60 are then placed to bridge the support bar 56 and the previously laid fuel pieces 60. Randomly sized imitation coals, logs orthe like 62 maythen be placed randomly over the finger fuel pieces 60 to produce a natural solid fuel fire appearance.The gas/air mix tu re emanating from the tu be 15 can permeate through the apertures 55 in the matrix 54 and through the spaces between the fuel pieces 59,60,62 wheretheyare ignited to produce a realistic solid fuel fire effect. The surface of the plaque 20 will glow and radiate heat therefrom and the ceramic back brick 51 and side cheeks 52 also radiate heat into the room so that the fire is as efficient as possible.

Referring now to Figures 10 and 11 there is shown a heat exchanger 63 which may be incorporated in either of the previously described embodiments of gas fire. The heat exchanger 63 comprises a plurality oftubes 64 which are disposed in spaced array behind and above the fire so that the combustion gases 65 passing tothe chimney orflue 66 can pass around the tubes 64. The lower ends ofthetubes 64 which have insulation 70 disposed atthe rear thereof are connected to a collector box 67 having an air inlet68 adjacent its base so that cold air can be drawn therein from the room as shown in Figure 11 .The cold air passes up the tubes 64, where it receives heatfrom the combustion gases 65 and hot air passes out of the outlet 69 above and in front ofthe fire. By this means, some of the heat is removed from the combustion gases and passes into the room due to the convection of the airthrough the tubes 64. The heat exchanger 63 replaces the back brick 51 and blanket spacer 53 as shown in Figures 5 to 7.

Claims (23)

1. A solid fuel effect gasfire comprising a chamber, a gas injector operable to inject gas into said chamber and to entrain air from adjacent said injector to pass into said chamberwith said injected gas to be mixed therewith in said chamber, the upper surface of said chamber comprising a perforated radiant plaque through which said mixture may pass, and a plurality of pieces of non-combustible imitation fuel disposed above said chamber providing spaces therebetween in which combustion of said mixture may be effected.

2. A gas fire according to claim 1 wherein said plaque is a ceramic radiant plaque.

3. A gas fire according to claim 2 wherein said plaque has a plurality of apertures therein disposed substantially uniformly spaced over the surface thereof.

4. A gas fire according to claim 3 wherein the plaque has an upper surface of multi-pyramidal shape.

5. A gas fire according to anyone of claims 1 to4 wherein said plaque is disposed substantially horizontally.

6. A gas fire according to any one of claims 1 to 5 wherein said chamber has a peripheral lip on which said plaque is non-securedlysupported.

7. Agasfire according to anyone of claims 1 to 6 comprising spacing means of a non-combustible material located adjacent said plaque, whereby said imitation solid fuel pieces are spaced from said plaque to form a combustion space therebetween.

8. A gas fire according to claim 7 wherein said spacing means has at least one aperture extending therethrough through which said mixture may pass.

9. A gas fire according to claim 7 or claim 8 wherein said spacing means comprises a ceramic fibre blanket.

10. A gas fire according to claim 9 comprising a ceramic back brick disposed to be upstanding at the rear of and supported by said blanket.

11. A gas fire according to claim 9 or claim 10 comprising a ceramic side cheek disposed to be up- standing at each side of and supported by said blanket.

12. Agasfire according to any one of claims 1 to 11 comprising a venturi tube extending across said chamber, said venturi tube having an opening at one end thereof adjacent one side of said chamber and adjacent which opening said gas injector is located.

13. Agasfire according to any one of claims 1 to 12 comprising a gas control operable to control the quantity of gas supplied to said gas injector.

14. A gas fire according to any one of claims 1 to 13 comprising a flame control operable to deflect the flowofgas issuing from said injectorandcausethe flow of air/gas mixture passing into said chamberto be turbulent.

15. A gas fire according to any one of claims 1 to 14 wherein said chamber is formed in a grate.

16. A gas fire according to claim 15wherein said grate is of cast iron.

17. A gasfire according to claim 12 or any claim dependent thereon comprising a deflector plate disposed above said venturi tube at the end thereof remote from said injector, said remote end of said tube having a second opening therein.

18. Agasfireaccordingto anyoneof claims 1 to 17 comprising a heat exchanger.

19. Agasfire according to claim 18wherein said heat exchanger comprises a plurality of tubers disposed to extend in spaced array behind and above said fire and between which combustion gasesfrom said fire may pass.

20. Agasfireaccordingto claim 19whereinan in let end of each tube is located at the rear and below said chamber.

21. A gas fire according to claim 19 or claim 20 wherein an outlet end of each tube is located above and in frontofsaid fire.

22. A gas fire substantially as hereinbefore describedwith reference to and as illustrated in Figures 1 to 4 or Figures 5 to 9 of the accompanying drawings.

23. Agasfire according to claim 22 substantially as hereinbefore described with reference to and as illustrated in Figures 10 and 11 of the accompanying drawings.