GB1029603A - Improvements in flow control valves - Google Patents

Abstract

1,029,603. Valves. GENERAL ELECTRIC CO. Feb. 25, 1965 [Feb. 27, 1964], No. 8132/65. Heading F2V. [Also in Division F1] The invention relates to a reheat fuel control of a gas turbine jet engine and particularly to a flow control valve in the fuel supply line of a reheat pilot burner system. In the gas turbine jet engine of Fig. 1 (not shown) fuel passes through line 20 to the burners 19 of the main combustion equipment, Fuel may also be supplied from the supply 27 to the reheat burner nozzles 30 by way of pump 35, reheat fuel control 32 and line 30. When reheat is switched on, fuel under pressure is directed by valve 34 through line 38 to the pilot burner valve 39 which causes fuel to be discharged through line 41 to the pilot burner nozzle 42 in the reheat combustion section where the fuel is ignited thus providing a pilot flame for the fuel supplied to the main reheat fuel burners 30. The pilot burner valve 39 is shown in Fig. 2 and comprises a housing 46 which forms a cavity 50 in which is disposed a piston 51. The housing 46 is formed with an inlet 47 to which is connected a line 40 leading from the fuel line 20 to the main combustion section 14, an inlet 48 to which is connected the fuel line 38 leading from the valve 34 of the reheat fuel system, and an outlet 49 which leads through line 41 to the reheat pilot burner 42. In normal engine operation the valve is disposed as shown in Fig. 2 in which the piston 51 is biased by the spring 57 to the left so that the extension 58 of the piston bears against the valve seat 59 to close off the outlet to line 41. No fuel pressure is applied in line 38 so that the chamber 50c is vented to atmosphere. Fuel pressure in the line 20 is communicated through line 40, filter 55 and restrictor assembly 56 to the chamber 50a at the right-hand side of the piston 51. This fuel passes through the bore 61 in the extension 58 of the piston, through openings 62 to the chamber 50b which is sealed at the valve 59. When reheat is switched on fuel under pressure passes through line 38 to the pilot burner valve 39, through inlet 48 to the compartment 50c at the left-hand side of the piston 51 whereupon the piston moves to the right and fuel in the chamber 50a is forced through the bore 61 and openings 62 into the chamber 50b and from there through the valve 59 which is now open to the line 41 and so to the pilot burner 42 of the reheat combustion equipment. Fuel will also pass from the line 20 (which leads to the main combustion section) through line 40 to the chamber 50a and thus through line 41 to the pilot burner 42 as long as piston 51 is held to the right by fuel pressure in chamber 50c. Fuel will simultaneously flow through line 33 to the reheat fuel control 32, through line 31 to the main reheat burner 30. When reheat is switched off, the chamber 50c is vented to atmosphere through line 38, the piston 51 is moved to the left to the position shown in Fig. 2 and the chamber 50a is re-filled ready for the next reheat operation.