Patent ID: 8141790
Filing Date: 2012-03-27
Classification: F01P,F16K,G05D,Y10T

Abstract:
1. A by-pass valve for a heat exchanger circuit for cooling a heat exchange fluid, comprising: a valve housing formed with a valve chamber and having first and second ports for respectively supplying and returning said heat exchange fluid to and from said chamber and third and fourth ports for respectively supplying and returning said heat exchange fluid to and from a cooler; a thermally sensitive actuator mounted in said chamber and having a shaft section and a piston extending from a first end of said actuator, said piston being adapted to extend from or retract into said first end in dependence on the temperature of said shaft section, said piston extending into and held by a recess formed in said housing at one end of said chamber so that said shaft section is movable in said chamber in response to extension or retraction of said piston; a spring enclosure mounted in a by-pass section of said chamber adjacent a second end of said actuator remote from said first end, said spring enclosure forming a valve seat having a by-pass port through which said heat exchange fluid can flow in a cold by-pass state of the valve and forming at least one pressure relief port; at least one port closing device mounted in or on said enclosure and adapted under normal operating conditions to close said at least one pressure relief port; a by-pass valve member mounted on said shaft section and movable by said actuator from a first position where said by-pass port is open to a second position where said by-pass port is closed by said by-pass valve member; and a return spring mounted in said enclosure and having one spring end engaging said actuator at said second end thereof so as to bias said shaft section away from said valve seat and the by-pass port, wherein, in the event of an excessive pressure build up in said chamber on the actuator side of said valve seat during use of the by-pass valve, said at least one port closing device moves to an open position and allows said heat exchange fluid to flow through said at least one pressure relief port and thereby reduce the pressure build up.