GB677697A - - Google Patents

Abstract

677,697. Igniting and controlling burners. PEABODY, Ltd. Nov. 9, 1950 [March 27, 1950], No. 27386/50. Classes 75(i) and 75(iii) An igniter and flame detector unit for a furnace fired by a gas, pulverized solid, or oil fuel burner comprises a housing having an outlet opening for communicating with the combustion space of the furnace adjacent the burner, and an ignition burner within the housing arranged to project flame through the said opening for igniting the main burner, the housing also being provided with flame detectors for respectively indicating the presence of flame at the ignition burner and at the main fuel burner of the furnace with which the unit is associated. In the embodiment shown the housing 20 is fan-shaped, comprising convergent tubes 21, 22, 23, 30, 31, and is provided with two ignition burners, one in each of the tubes 21, 23, each comprising a gas supply tube 40 and a cup-shaped mouth 44 having perforations 46 for the passage of a portion of the air for combustion supplied through a pipe 45. A spark ignition electrode 47 enters through each tube 40 into the cup 44. The tubes 30, 31 support flame detector rods 32, 33, respectively, arranged to project into the path of the flames from the two ignition burners, whilst the tube 22 supports a flame detector rod 25 projecting from the housing 20 through an opening 24 into the path of the main burner flame. If the main burner is an oil or a pulverulent fuel burner the flame rod 25 may be replaced by a photo electric flame detector. In operation gas is supplied to the igniter burner tubes 40 and simultaneously the ignition electrodes 47 are energized. The resulting ignition burner flames play on the detector rods 32, 33, which may be connected in a control system in such a manner that flame detection by either one or both rods is necessary to open a fuel valve controlling the supply to the main burner. Normally the said fuel valve opens, the main burner is ignited, and after a predetermined period the ignition burners cease operating, the flame detector 25 then controlling the main burner fuel valve to close the latter in the event of the main burner being extinguished.