GB744451A - Improved purging gas generator - Google Patents

Abstract

744,451. Generating combustion products under pressure. STEWART-WARNER CORPORATION. Dec. 8, 1953 [Dec. 9, 1952], No. 34174/53. Class 51 (1). [Also in Group XIII] The invention relates to apparatus for generating purge gas to be supplied to compartments, for example in an aircraft, in which inflammable vapour may collect. The apparatus comprises essentially the combination of a combustion chamber in which combustion products are generated by the combustion of fuel in air under pressure, and a heat-exchanger in which the combustion products are cooled before passing to the compartments. The combustion apparatus comprises a flame tube 118 to which combustion air is supplied from the duct 24 through the tube 130 to a chamber formed by the walls 112,114, the air entering the flame tube through slits 126 in the conical end wall 120. Fuel is supplied from the injector 136 and ignition is caused by a sparking plug 86, these two components being mounted on a spider 122 mounted on a ring 124. The downstream end of the flame tube is open but the surrounding shell 108 is closed by a plate 110. Gases pass from the open end of the flame tube and through the opening 128 into the annular space around the flame tube within the shell 108. The gases then pass successively into the two annular spaces formed by the shells 104, 106 'and 98, 100 and finally discharge through the outlet 40. The gases are caused to travel circumferentially within the annular spaces by the positioning of the interconnecting passages. Cooling air flows around the shells 98, 100 and 104, 106 in an upstream direction, these shells constituting a primary heat-exchanger. Air is supplied, for example, from the compressor of a gas turbine jet propulsion engine through the inlet valve 97, the air passing through an automatic pressure regulator 18, through the venturi 22, 24 where the mass flow is measured by means of tappings 28, 30 which are connected to the fuel-air ratio controller 26. Fuel is supplied through the supply line 32, filter 34, an electricallyoperated on-off fuel valve 36, an automatic pressure regulator 37 and thence to the fuel-air ratio controller which modulates the flow so that an amount of fuel proportionate to the rate of air flow will be supplied to the injector 86. The combustion products after passing the primary heat-exchanger 98, 100, 104, 106 pass through the duct 40 to the secondary heat-exchanger 44, 46 48, 50 and are delivered through the duct 52 through a carbon and water separator 54, through a pressure relief valve 56 to a three-way starting valve 93. The cooled gases may then pass through the duct 95 to mix with the cooling air flow, during starting and until the gases become of a satisfactory quality. Once the gases are satisfactory they pass through the duct 64 to the compartments that are to be purged. The electrical control circuit is described with reference to Fig. 8 (not shown).