Pressure relief valve

摘要

1,046,307. Valves. INTERNATIONAL STANDARD ELECTRIC CORPORATION. April 15, 1965 [April 23, 1964], No. 16172/65. Heading F2V. In a pressure relief valve for a hot water boiler 11 of a hot water system, the closure assembly 19 is raised from seat 18 by pressure acting on the underside of diaphragm 21 seated by a spring 32 and full opening of the valve upon accidental rupture of the diaphragm 21 is ensured by providing a disc 28 with a turned down flange 46 secured to the underside of the diaphragm 21 and of a diameter slightly smaller than that of the chamber 14 whereby full pressure may act against disc 28 which is moved against the inner surface of bonnet 23, with the edge of the ruptured diaphragm therebetween. The tension of spring 32 is adjustable by a nut 36 and supplementary manual actuation is effected upon rotation of handle 39 and engagement of a cam surface 41 thereof against bonnet cup 42. The bonnet 23 is provided with a relief opening which may be loosely covered by cover 51 which is burstable from rivets or retaining screws 52. In an alternative embodiment (Fig. 2, not shown) the disc 28 is mounted with radial play on the diaphragm assembly to assist centering thereof when the diaphragm ruptures.