Apparatus for monitoring a valve

摘要: A safety valve, coupled to a pressure chamber, includes closure element which is translatable substantially along reference axis. The device spindle nut (60) and an associated extension member adapted for coupling the (14) of valve. annular permanent magnet (76) positioned thereon having its principal axis co-linear with first (70). This assembly provides uniform magnetic field at periphery symmetrical about further cylindrical housing (40) generally inner surface extends uniformly displaced from all positions as moves one or more reed switches (50, 52) in close proximity aligned their parallel spacing between selected so that passes switches, switch changes open closed, then back again.