GB816553A - Fuel control means for gas turbines - Google Patents

Abstract

816,553. Gas turbine plant. LUCAS (INDUSTRIES) Ltd., J. May 23, 1957 [May 24, 1956], No. 16069/56. Class 110 (3). [Also in Group XXIX] In a gas turbine fuel control system including a variable delivery pump q in which pump output pressure acts on a piston y and atmospheric pressure on an evacuated capsule w to control a leak-off valve 4 carried on a pivoted lever u to control a servomotor piston 7 regulating the pump output, the compressor b driven by the turbine a and supplying air to the combustion chamber d also supplies air for a secondary purpose. The secondary air passes through a duct e controlled by a valve k interconnected with a valve m controlling a passage f connected to atmosphere and to a chamber s housing a diaphragm x connected to the lever u. With the valve m closed and the valve k open to supply secondary air, pressure builds up beneath the diaphragm to move the leak-off valve 4 towards closure so that the servomotor piston 7 moves to increase the pump output to its maximum value to automatically vary the air to fuel ratio to the combusion chamber. On the valve k being closed and the valve m opened, air from beneath the diaphragm escapes to the atmosphere so that the valve 4 opens wider to reduce the pump output. Intermediate rates of supply of fuel to the combustion chamber are obtained by varying the positions of the valves k, m relatively to their seatings. The piston y or an equivalent diaphragm instead of being subjected to pump output pressure may be subjected at its opposite sides to a pressure difference related to the rate of flow of fuel supplied by the pump. A spring- loaded control valve 14 may be provided between the pump and the combustion chamber.