A pressure balanced thermal actuator includes a flow housing having an inlet and an outlet, with the flow housing being affixed at opposing ends to two bellows housings, each of which contains a bellows. An actuation rod is operably coupled to each bellows and contains a fluid passage therewithin. When the temperature of the area surrounding the actuator increases, the pressure inside the bellows housings increases, and exerts a force on the bellows therein, compressing it. As a result, the actuation rod moves from a first position to a second position to align the fluid passage with the inlet and the outlet, enabling the controlled passage of a first fluid from the inlet, and through the fluid passage, to the outlet, to reduce the temperature of the area surrounding the valve assembly. The actuator is unaffected by changes in the ambient pressure, by working equally on two opposing bellows areas.

An internal combustion engine cooling device includes a piston fixedly mounted within a device housing coupled to a plurality of flow paths through which cooling water flows, the piston disposed facing the interior of the device housing; a cylinder container that advances and retreats relative to the piston and has a flange valve that opens and closes a main flow path of the cooling water; a thermal expansion unit provided within the cylinder container that causes the cylinder container to advance and retreat due to volumetric changes attendant upon temperature changes; and a heat-emitting element provided within a piston casing that heats the thermal expansion unit when supplied with electricity. An insulating cover is provided to the exterior of the cylinder container at a portion of the cylinder container disposed facing the cooling water.

A resettable thermal pressure relief device (TPRD) is disclosed. The TPRD includes a piston, a housing adapted to receive the piston and allow movement between an open and a closed position. The housing includes an actuator having a temperature sensitive material disposed therein. The temperature sensitive material volumetrically expands, increasing a length of the actuator and forcing a lever from a first position to a second position. The piston is held in the closed position by the lever in the first position. When the lever moves to the second position, the piston is allowed to move to the open position, allowing a fluid to flow through the TPRD from a high pressure vessel in communication therewith.

A pressure balanced thermal actuator includes a flow housing having an inlet and an outlet, with the flow housing being affixed at opposing ends to two bellows housings, each of which contains a bellows. An actuation rod is operably coupled to each bellows and contains a fluid passage therewithin. When the temperature of the area surrounding the actuator increases, the pressure inside the bellows housings increases, and exerts a force on the bellows therein, compressing it. As a result, the actuation rod moves from a first position to a second position to align the fluid passage with the inlet and the outlet, enabling the controlled passage of a first fluid from the inlet, and through the fluid passage, to the outlet, to reduce the temperature of the area surrounding the valve assembly. The actuator is unaffected by changes in the ambient pressure, by working equally on two opposing bellows areas.