GB695283A - Improvements relating to apparatus for supplying liquid fuel to continuous combustion turbine engines - Google Patents

Abstract

695,283. Gas turbine plant. DOWTY EQUIPMENT, Ltd. June 11, 1951 [June 9, 1950], No. 14490/50. Class 110(iii) [Also in Group XXIX] Apparatus for controlling the fuel supply to the burners of a continuous combustion turbine in relation to the air mass flow, comprises a vent valve 12 controlling a servo device by which the rate of fuel supply is controlled, additional to a vent valve under the direct control of an operator's speed control member (not shown). The valve 12 is carried by a lever 13 pivoted at 14 and subjected at one end to a bellows 15 to which air is supplied from the engine air compressor and is a measure of the air mass flow to the engine, and at its other end to a spring 20 the force of which is varied by an adjustable spring 21 to give a force which is a measure of the fuel flow. Spring 21 is adjustable by a member 22 which controls fuel flow from inlet 23 to outlet 26 and the pressure drop across the member is applied through conduits 29, 30 to the interior and exterior, respectively, of a bellows 28, which operates through a rod 41 a lever 39 pivoted at 40 and loaded by a spring 42. The lever carries a vent valve 36 controlling the pressure in a chamber 33 to which pressure fluid is supplied through an orifice 32a in the member 22. Thus the member 22 will be positioned to maintain the pressure drop constant, and the position of the member and hence the loading of the spring 21 will be a measure of the fuel flow. Fuel escaping past the valve 36 returns to the pump inlet through a passage 38, chamber 17 and passage 19. Bellows 16 is provided to prevent pressure variations in chamber 17 affecting the lever 13. The apparatus will thus provide a constant fuel/air ratio for all engine speeds. In order to increase this ratio above and below a critical speed range throughout which the constant ratio is desirable, a loading lever 44 pivoted at 45 is arranged to load lever 39 when engine speed is either above or below the critical range. Lever 44 is acted on by a spring 43 and a bellows 48 supplied with pressure fluid from an engine-driven centrifuge to provide a force on the lever which is a measure of engine speed. The pressure in the bellows and the spring balance each other throughout the critical range, but below and above the lever 44 will tilt clockwise and anticlockwise, respectively, to engage the lever 39 and thus increase the closing force of vent valve 12 to increase the fuel flow. If desired, the end 46 of lever 44 may be prevented from engaging the lever 39 so that no increase of fuel flow takes place below the critical speed range.