GB191307495A - Improvements in Valve Mechanism. - Google Patents

Abstract

7495. Jackson, W. J. Mellersh-, [Galvin, T., and Smith, C. C.]. March 29. Valves controlled from a distauce; pressure-regulating v a l v e s.-A fluid-pressure actuated lift valve particularly applicable for use with h i g h - p r e s s u r e fire hydrants is adapted to be controlled by opening and closing a valve in the nozzle of the delivery hose and under certain conditions of flow is adapted to maintain a constant reduced pressure in the outlet, while when the main valve is closed a drain valve on the outlet side is adapted to be automatically opened. The main valve 14, which is normally pressed to its seat by a spring 20, is formed integrally with its actuating-piston 14<a> and has a removable valve face 17 held in position by a removable part 16 secured to the valve member by a nut 16<a>. The piston works in a cylinder 19 formed in a part 6 supported axially in the casing 1 by ribs 7. Inlet pressure is admitted to the cylinder by a port 18 and exhausted through a port 21 controlled by a manually-controlled plug cock and a piston valve 25, actuated by outlet pressure acting on a piston 27 against the action of an adjustable spring 29. Under full flow, the auxiliary valve is locked in its open position by a cam catch 38 actuated against the action of a spring 44<a>, by fluid flow acting on a reciprocating plate 41. A piston valve 50 is coupled to the main valve and is adapted when the main valve is closed to open a drain port 52 on the outlet side of the main valve to relieve the pressure in the outlet. To prevent the outlet pressure from falling so far as to allow the auxiliary valve 25 to open, the outlet of the drain valve is fitted with a spring- loaded ball relief valve 55. The casing is fitted with a carrying-handle 31 and with a removable plug 59 to facilitate the attachment of a pressure gauge.