GB1166895A - Improvements in Gas Fires - Google Patents

Abstract

1,166,895. Heating air for combustion; incandescent gas fires. GAS COUNCIL. 19 March, 1968 [4 April, 1967], No. 15340/67. Heading F4W. Some of the hot combustion products from a gas burner 5 in a gas fire are drawn by a fan 19 through a gas-permeable rear panel 3 of the radiant into a chamber 8 formed behind said panel and thence through a heat exchanger 16 in which combustion air for the burner is preheated. The unit is enclosed by a casing 1 which is open at the front (detail not indicated) for the emission of heat from the radiants, and for the discharge to a room or like of convected air heated on its passage through the casing. As shown, this air is blown downwardly by a fan 34 being guided en route by a deflector 36. Alternatively the fan may induce an air flow upwardly or, with the fan switched off, air flow is by natural convection. The radiant comprises front and rear ceramic panels 2, 3 having thorn projections 2a, 3a thereon. The rear panel 3 which may have thorn projections on both sides, has perforations 4 through its upper part. In use, some combustion gases pass upwardly between the radiant panels 2, 3 through a duct 28 and heat exchanger 29 to a flue 30. The remainder controlled by a baffle 25 are drawn by the fan 19, through the holes 4 in the rear radiant panel to the chamber 8 and pass thence through thin-walled tubes forming the heat exchanger 16, to a header 17, and thence via a duct 32 to a nozzle 33 in the flue 30 thereby inducing flow through the duct 28. Combustion air comprises a portion of the air delivered by the fan 34, this air being heated as it traverses the heat exchangers 29 and 16 en route to the burners 5. When the fire is operated at a lower heat output, the fan 34 is reversed or stopped to provide an upflow of induced or convected air some of which is preheated as it passes through the heat exchanger 16 to the burners. In this case also the damper 25 is turned to the position shown by dotted lines so that the combustion gases are withdrawn through the lower part only of the panel 3. The damper 25 may be operated manually, thermostatically, or in conjunction with the gas supply valve. At a still lower heat output the exhaust gas fan 19 may also be switched off and a damper 31 is then opened so that at least some of the resulting fume spillage from the radiants is directed into the exhaust duct 28. Flow of combustion of air is in this case assisted by opening a flap 37 in a chamber 6 containing the burners. The unit may in a modification, be adapted as a room-sealed unit. In this form, the radiants are closed by a glass plate 38 and the intake of the air fan 34 is arranged around the flue outlet 30 for connection to a balanced flue terminal.