GB794992A - Diaphragm valves - Google Patents

Abstract

794,992. Diaphragm valves. GRINNELL CORPORATION. March 14, 1955 [June 14, 1954], No. 7356/55. Class 135. A diaphragm valve comprises an operating stem on that side of the diaphragm remote from the valve seat having a portion in abutment with resilient means separate from or integral with the diaphragm, actuating mechanism for reciprocating the stem to move the diaphragm towards or away from its seat, a compressor carried by the stem engageable with said remote diaphragm side and a connecting member carried by the diaphragm and projecting from its said remote side to operatively engage the stem. As shown in Fig. 1, the diaphragm 22 is engageable with a seat 30, is formed with a tubular boss 74 in abutment with a screwthreaded stem 38 and carries a connecting member comprising an embedded stud 76 and collar 78. The stud 76 is formed with an elongated slot 82 engageable with a pin 64 which passes through the stem 38 and a compressor 60. On actuation of a hollow screw-threaded bush 34 by a handwheel 46 to move the diaphragm towards its seat, the pin 64 moves out of operative engagement with the stud 76 so that the stud does not damage the diaphragm when the latter is pressed on to its seat. On actuation in the opposite direction the pin 64 engages the stud with lost motion to positively move the diaphragm away from its seat and thus permits the valve to be used in a vacuum system. The diaphragm may be made of natural or synthetic rubber or of plastic material such as trifluorochloroethylene. When the latter material is used owing to its low resilience the diaphragm has to be made thin necessitating the fitting of a backing plate of synthetic rubber. In this case it is the backing plate which engages the stem and the compressor. In a modification, the connecting member comprises the stud 76, and a nut 106, Fig. 8, having a square head 110 which engages with lost motion in a T-slot 112 in the stem 38.