William F Ekern Deceased5106 Independence Dr, Fairfield, CA 94533

4470450, Sep 11, 1984

Oct 22, 1981

6/313737

Gary D. Bizzell - Los Altos CA
William F. Ekern - Sunnyvale CA

Lockheed Missiles & Space Co. - Sunnyvale CA

F28D 1500

16510425

A closed-loop heat transfer system comprises a heat pipe (10) and an external liquid-phase pump (11). The heat pipe (10) includes an evaporator (12) and a condenser (13) connected by a conduit (14). The evaporator (12) is a hollow structure having an interior surface defining an evaporation region in which a working field in liquid phase absorbs heat from a heat source by evaporation. A capillary pumping structure, e. g. , capillary channels (30) or a fine-mesh screen (41), is provided on or adjacent the interior wall of the evaporator (12). Evaporated working fluid laden with heat is thermodynamically driven substantially adiabatically via the conduit (14) from the evaporator (12) to the condenser (13), wherein the working fluid rejects heat to a heat sink by condensation. Condensed working fluid is thereupon returned from the condenser (13) to the evaporator (12) via external conduits (22, 15) by means of the liquid-phase pump (11). The capillary pumping structure inside the evaporator (12) serves to maintain a constant supply of working fluid in liquid phase adjacent the interior surface of the evaporator (12), thereby promoting efficient transfer of heat from the heat source to the working fluid in the evaporator (12).

4492266, Jan 8, 1985

Dec 22, 1983

6/564410

Gary D. Bizzell - Los Altos CA
William F. Ekern - Sunnyvale CA

Lockheed Missiles & Space Company, Inc. - Sunnyvale CA

F28D 1500

16510426

As illustrated in FIGS. 5A, 5B and 5C, a manifolded evaporator (60) comprises a closed evaporation chamber (61) and a delivery structure (62) through which liquid-phase working fluid is delivered into the evaporation chamber (61). One wall (63) of the evaporation chamber (61) is positioned to intercept a flux of heat from a heat source. A wick structure (64), such as a fine-mesh metallic screen, is secured adjacent the wall (63). The delivery structure (62) comprises an elongate supply phenum (65), an elongate recovery plenum (66), and a plurality of delivery conduits (67) connecting the supply plenum (65) to the recovery plenum (66). Each of the delivery conduits (67) is of generally U-shaped configuration with a transverse portion running inside the evaporation chamber (61) immediately adjacent the wick structure (64). A slot (68) along the transverse portion of each delivery conduit (67) allows liquid-phase working fluid to flow out of the delivery conduit (67 ) into the wick structure (64). Working fluid in liquid phase is distributed by capillary action throughout the wick structure (64), whereby liquid-phase working fluid is constantly available adjacent the wall (63) to absorb heat from the heat source by evaporation.