Patent ID: 7380767
Filing Date: 2008-06-03
Classification: F25B,G05D

Abstract:
1. A valve comprising a housing having an inlet and an outlet, and a pressure sensing port, a piston slidable in a part of the housing in response to a difference between a first fluid pressure at the pressure sensing port on the one side of the piston, and a second fluid pressure at the inlet and/or outlet on the other side of the piston, a valve member carried by the piston and operable thereby to close the inlet when said second fluid pressure is less than a value sufficiently greater than said first fluid pressure; wherein the valve member is movable with respect to the piston to facilitate closing of the inlet, in response to a fluid flow from the housing to the inlet, biasing means being arranged to bias the valve member with respect to the piston to close the inlet, when the piston is not acting to close the inlet, wherein manual shut-off means comprising a spindle having a non-round proximal portion and a threaded distal portion are provided for closing the valve, and wherein said distal portion is engaged in a non-rotatable threaded sleeve, the sleeve being slidable along the distal portion between a normal position in which the piston is movable and a maintenance position in which the sleeve retains the piston and the valve member in the closed position.