INTERNAL TANK VALVE

摘要

1506869 Valves ANDERSON, GREENWOOD & CO 15 Sept 1975 [31 Jan 1975] 37833/75 Heading F2V An internal tank valve comprises a seat ring 18 welded to the tank base 14 and defining an opening in alignment with an inlet or outlet line, the opening being closable by a valve member 22 having supporting and guiding means ensuring vertical movement relative to seat 18 whilst minimizing vertical forces transmitted to the tank bottom. The supporting and guiding means comprise angularly spaced upstanding legs 44 secured to seat 18 and supporting a circular upper plate carrying sockets 54 in which slide valve member guide rods 52. The latter are surrounded by springs 58 to damp shocks in the fully open position of the valve. Additional guidance is provided by plates 48 pivotally connected to valve member 22 and via links 40, 50 to legs 44. The links 40 and valve stem 38 are respectively connected by cables (24), 26 to "close" and "open" piston and cylinder actuators (28, 30, Fig. 1, not shown) controlled by a pilot valve (34). A manual actuator (36) is also provided. In modifications the valve may be operated by mechanical or electromechanical means driving a cable drum, by a jack screw, or by a rack and pinion. Stem 38 can move axially to a limited extent relative to valve member 22, against the bias of spring 62, such that during initial opening movement a disc on the stem unseats from member 22 to permit pressures across the latter to be equalized by flow through passages 64, 66. Baffles 60 stabilize the main fluid flow. Seat 18 includes a resilient seal 42.