IMPROVEMENTS IN OR RELATING TO FLUID VALVES, PARTICULARLY FLUID VALVE FOR VACUUM INSTALLATIONS

1281556 Valves INSTITUT FIZIKI POLUPROVODNIKOV SIBIRSKOGO OTDELENIA AKADEMII NAUK SSSR 8 Dec 1969 [20 Feb 1969] 59757/69 Heading F2V A valve for a vacuum installation comprises a closure member 1 co-operating with a seat 16, a bushing 5 with side projections 7 movable with the closure member, linear guides 8 in the valve body to receive the side projections 7, flats 12, 13 on the projections and on the body slanted at the same acute angle to the longitudinal axis of the valve, a lever 22 for moving the bushing in the linear guides 8, and a recess 11, beneath the linear guides in which the flats on the bushing may be rotated into engagement with those on the body by turning the lever about the longitudinal axis of the valve so that the closure member is pressed against its seat. A metal bellows 26 biases the closure member to half-open position and a key 32 prevents rotation of the valve stem when the bushing 5 is turned to cause the flats to force the valve against its seat. Initial movement of the valve towards its seat is produced by rotating levers 22 about their pivots 21. The valve body, bushing and stem are made of stainless steel and movable parts may be coated with cadmium or molybdenum disulphide to prevent seizure at high temperatures. The closure member is of copper alloy.