Wick-Interrupt Temperature Controlling Heat Pipe
Patent, Filed 12 Sep 96, patented 30 Jun 98
DEPARTMENT OF THE NAVY WASHINGTON DC
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The wick-interrupt temperature controlling heat pipe WITCH is a device for controlling the temperature of spacecraft temperature-sensitive, heat dispensing devices. A heat transporting working fluid is conveyed in saturated equilibrium with its vapor across a discontinuous internal capillary liquid wick, within a tubular cylindrical pressure vessel, from a condenser section to an evaporator section located on either side of the discontinuity. When the temperature within the WITCH rises to a predetermined level, a sliding wick located within the internal capillary liquid wick is inserted across the discontinuity by a temperature sensitive control rod, thereby allowing the heat transporting working fluid to circulate from the condenser section wick to the evaporator section wick. In this configuration, the WITCH operates identically to the constant-conductance heat pipe commonly used. When the components or heat pipes temperature drops to a predetermined level the control rod contracts relative to the heat pipe vessel wall and retracts the sliding wick, again crating a wick discontinuity between the evaporator and condenser sections and thereby interrupting the flow of the heat transporting working fluid and causing evaporator dry-out and curtailment of heat pipe operation. This ON and OFF heat pipe operation is the means whereby temperature is actively controlled to within a narrow range while heat transport varies over a wide range.
- Air Conditioning, Heating, Lighting and Ventilating