Patent attributes
A by-pass valve for a heat exchanger circuit that includes a cooler has a chamber and ports for flow of fluid into and out of this chamber. A thermally sensitive actuator is mounted in the chamber and can extend or retract in dependence on its body temperature as influenced by temperature of the fluid. A by-pass valve seat is arranged in a valve housing along with a by-pass valve member movable by the actuator into or out of engagement with the seat. A relief valve is mounted in the chamber and has a relief valve member movable between closed and open positions in order to close or open pressure relief ports. This relief valve member is biased towards the closed position. Excessive pressure build up in an end section of the chamber causes the relief valve member to move to its open position.