GB891051A - An improved ball-cock - Google Patents

Abstract

891,051. Valves. CLARIDGE, G. H., and MAINDONALD,C. J. June 20, 1960 [June 26, 1959], No. 21591/60. Class 135. A ball-cock for a flushing cistern, comprises a valve body 1, Fig. 1, having a chamber 2 in which a valve member 7, operable through a float-arm 17, controls flow between an inlet 4 and outlet 6, and a flexible diaphragm 11 secured to the valve member and the body in such a position that the inlet communicates with the valve chamber between the diaphragm and the outlet, the effective areas of the diaphragm and the closure portion 9 of the valve member being such that, in the closed position of the latter, liquid under pressure within the valve chamber exerts a greater pressure on the portion 9 in the direction of closing of the valve than it exerts in the opposite direction on the diaphragm. The diaphragm is clamped in the body 1 at its outer periphery by means of a plug 12 and a nut 13 and secured at its centre to a valve spindle 7. A restriction 20 is provided in the outlet 6. In operation, with the valve in the closed position shown in Fig. 1, liquid in the chamber 2 acts on the valve member 9 and maintains the valve closed since the effective area of the latter is greater than that of the diaphragm. When the cistern is emptied, the float arm 17 drops and its pivoted short end, which in the closed position is clear of the end of a clearance slot 18 in the valve spindle, abuts the end of the slot and thereby lifts the valve from its seat; liquid then flows past the valve and, due to the restriction 20, a back-pressure is developed which, together with the liquid pressure acting on the diaphragm, causes the valve to rapidly lift to the fully open position shown in Fig. 2. When the cistern is nearly full, the end of the lever 17 abuts the opposite end of the slot 18, thereby moving the valve towards its seat and causing a reduction in the back pressure; the pressure in the chamber 2 then rapidly closes the valve. In the modification shown in Fig. 4, the restriction in the outlet may be formed by reducing the diameter of the outlet pipe 22, of flexible material such as synthetic resin, by means of a rubber ring 24 ; more than one such restriction may be formed. In a further modification, the conical-shaped seat 10 for the valve member 9 is replaced by a raised lip co-operating with a plain surface on the valve member 9.