Abstract: A thermally actuated heat pipe control valve including a housing, a phase change material actuator, and a passage closing member. A passage extends through the housing and is configured to receive working fluid from the heat pipe therein. The phase change material actuator is positioned in the housing and has a sealed chamber with phase change material positioned therein. The passage closing member is positioned in the housing proximate to or in the passage and proximate to the phase change material actuator. The passage closing member has a surface which cooperates with a wall of the passage. As the temperature of the phase change material reaches a designed temperature, the phase change material melts and expands causing the passage closing member to move into the passage to a closed position, preventing heat transfer between the condenser portion and the evaporator portion when the designed temperature is reached or exceeded.

Abstract: A thermally actuated heat pipe control valve which includes a housing having a first opening for receiving a condenser portion of a heat pipe therein, a second opening for receiving an evaporator portion of the heat pipe therein and a passage extending through the housing from the first opening to the second opening. The passage is configured to receive working fluid from the heat pipe therein. A passage closing member is positioned in the housing proximate to or in the passage. The passage closing member having a surface which cooperates with a wall of the passage. At a specific temperature, the passage closing member moves into the passage to a closed position, preventing the flow of the working fluid, thereby preventing heat transfer between the condenser portion and the evaporator portion when the design temperature is reached or exceeded.