GB797190A - Improvements in and relating to fluid controlling valves - Google Patents

Abstract

797,190. Valves. SAUNDERS VALVE CO., Ltd. May 25, 1955, [May 27,1954] No. 17907/57. Divided out of 797,189. Class 135. A fluid control valve has a closure member 29 carried by a movable member which has some freedom of motion in relation to the valveoperating mechanism under spring bias towards the closed position, this freedom of motion being partly taken up against the spring bias when the valve is closed. The inlet pressure has access to an area E-D at the back of the movable member greater than the area A within the seating area when the valve is closed so that the valve is held closed mainly by the inlet pressure and is positively opened by the operating mechanism after the freedom of motion has been taken up. The movable member includes a piston body 13, a piston head 28, and a skirt 32. The body 13 has a sliding fit in a part of the valve casing and is sealed with respect thereto by a seal, such as the ring 14, located between the operating mechanism and the area at the back of the movable member to which the inlet pressure has access. The piston body 13 slides in a sleeve 22 mounted with a valve body 11 and held therein by an operating spindle 15 provided with sealing rings and a thrust collar 18. An eccentric pin 23 on the spindle 15 forms a pivot for one end of a connecting rod 24 the other end of which has a slot 41 forming a lostmotion connection with a pivot 25 on the piston body 13. A spring 43 tends to take up this lost motion. The head 28, together with a hard rubber or other resilient closure member 29 is secured on an extension 26 of the piston body 13 by a nut. The skirt 32 slides in a fluid-tight manner on the sleeve 22 and the annular space 35 between the parts is connected to the inlet through passages 36, 37. Two arcuate passages (not shown) in the body 11 connect a seating recess 39 in an inlet fitting 42 with a passage in an outlet fitting 47 faired off by a hemispherical or similar dome 48 having a central vent aperture and peripheral mounting lugs. The motion of the spindle 15 is limited to approximately 180 degrees by a projection engaging shoulders on a fixed plate 55 and in the closed position of the valve the pin 23 is just beyond the dead-centre position.