GB675865A - Improvements in or relating to fluid-pressure operated valve devices - Google Patents

Abstract

675,865. Valves controlled by auxiliary valves. UNITED AIRCRAFT PRODUCTS, Inc. July 4, 1949, No. 17633/49. Class 135. A fluid-actuated valve controlling the supply of steam to an aircraft gas turbine for starting purposes when on the ground comprises an open-ended tubular casing 11 formed at one end with a seat 16 coacting with a valve member 17 connected by a stem 27 to a piston 26 slidable in the casing and closed at its other end by a cap 34 mounting a solenoid 39 whose core 42 formed with a stem 48 actuates a pilot-valve 38 controlling an axial passage 36 through the piston, stem and valve member. The casing 11 is mounted in a part 12 of the turbine installation having chambers 13, 14 communicating with an external source of pressure steam and with the turbine respectively. The valve 17 loaded by a spring 24 is formed with a skirt 18 slidable in a looselymounted sleeve 19 housing a spring abutment disc 23 having a hole to connect the chamber 13 with the passage 36. On the closing of a switch, the solenoid 39 is energized whence its core 42 is moved to the left to permit the opening of the pilot-valve 38 and steam to pass to a space 35 behind the piston 26. The piston 26 then moves to the right to unseat the valve 17 to connect the chambers 13, 14 through ports 15 to supply steam to the turbine. On breaking the switch, a spring 47 moves the core 42 and the pilot-valve 38 to the right to close the passage 36, steam in the space 35 then escaping between the piston 26 and the casing 11 and through ports 51 to the atmosphere whilst the spring 24 seats the valve 17.