Patent ID: 6415815
Filing Date: 2002-07-09
Classification: F16K,G05D,Y10T

Abstract:
A pressure relief valve for relieving excess pressure in a fluid distribution system comprising:a valve body having an inlet port and an outlet port in communication with an interior of the valve body, the inlet port being connectable directly to the fluid distribution system; a valve member movable between a closed position to prevent fluid flow through the valve body and an open position to permit fluid flow through the valve body, the valve member being exposed to a first opening force exerted by the pressure in the fluid distribution system; an auxiliary chamber in the valve body isolated from the interior of the valve body; a movable member housed in the auxiliary chamber to divide the chamber into first and second regions and exposed to the pressure in the fluid distribution system, the movable member co-operating with the valve member to provide a second opening force for the valve member; an interface chamber having first and second sealed regions on opposite sides of a movable interface, a first conduit from the inlet port of the valve communicating the fluid of the fluid distribution system to the first interface chamber region, a second conduit communicating the second interface chamber region with the first region of the auxiliary chamber, and a second fluid in the second interface chamber region such that the pressure of the fluid in the fluid distribution system is transmitted via the movable interface to the second fluid to generate the second opening force at the movable member; and biasing apparatus to exert a default closing force to move the valve member to the closed position, the closing force being equivalent to a pre-selected pressure in the fluid distribution system whereby the first and second opening forces act to move the valve member to the open position whenever the pressure in the fluid distribution system exceeds the pre-selected pressure.