SAFETY APPLIANCE

摘要

1284653 Valves PATINVEST PATENTUND INVESTMENT AG 3 March 1970 [11 March 1969] 10026/70 Heading F2V A safety valve is adapted to close automatically in the event of a downstream leak developing after a predetermined quantity of fluid has passed through the valve. It can be used in either a gas or liquid supply conduit but its preferred use is in a water line feeding a washing machine or bath. In operation, with mains pressure connected at 5 and outlet 6 closed, valve plate 19 is sealed to close ports 17, diaphragm 37 is collapsed to the dotted line position and valve cone 31 is seated. Opening outlet 6 causes the plate 19 to open ports 17, resilient conical member 24 to deform and open a flow path 56 so that water flows to the washing machine through chambers 8, 43, 9 and outlet 6. Simultaneously the reduction in pressure in chamber 9 causes diaphragm 37 to extend slowly to the full line position over a period determined by the size of orifice 47. When the predetermined quantity of water has flowed into the washing machine a valve therein should close automatically and this causes an equalization of pressure in the valve which results in the resilient member 24 returning to its conical shape and diaphragms 37, 50, valve plate 19 and cone 31 returning to their original positions (Fig. 1, not shown). If, however, the valve in the washing machine fails to close, or a leak in the piping develops, the diaphragm 37 continues to move towards member 24 which, due to the differential pressure across its faces, collapses to close the outlet 6 (Fig. 3, not shown). After the downstream defect has been rectified the valve is re-set by either removing a bleed screw (62, not shown) in wall 2 or removing the connection to outlet 6 and manually raising cone 31. Fig. 4 (not shown) illustrates a modified outlet valve assembly.