GB870804A - Improvements relating to valves for the control of fluids - Google Patents

Abstract

870,804. Valves. GWYNNES PUMPS Ltd., and WAUCHOPE, G. A. July 30, 1959 [Aug. 20, 1958], No. 26743/58. Class 135. A non-return valve for use in a pump delivery pipe to prevent return flow when the pump is closed down, comprises a housing 1, connected by flanges 2 in a pipe-line and an arcuateshaped valve member 3 of e.g. rectangular plan form, co-operable with a complementary seat 6 on an extension 7 of the upstream pipe section. The valve member 3 is convex on its upstream face and formed on its downstream face with a pair of lateral arms 4 mounted on trunnions 5 which extend outwardly from the housing to mount quadrants 12. The quadrants 12 carry counterbalance weights 13 or alternatively may be influenced by an hydraulic dashpot or motor. The axis a of the trunnions 5 is located at a level other than the axis of the conduit which is also the axis of curvature b of the valve member 3 and its seat 6. As shown, the axis a is below the axis b. If the valve is closed, there will, normally, be water under a static head downstream of the valve and no water or water at reduced pressure upstream thereof. Under these conditions, the moment of the pressure acting on the concave valve face about the axis a overcomes the moment of the weights 13 about this axis to keep the valve tightly closed. On starting the pump, the moment of the pressure acting on the convex face overcomes the moment of the oppositely directed pressure acting on the concave face to open the valve and retain it open until the pump again stops. Adjustable stops 9 and 10 limit the movement of the valve in its open and closed positions respectively. In a modified construction the concave face and the brackets are on the upstream side of the valve with the axis a located above the axis b.