Auxiliary evaporator for dual mode heat pipes

Claim 1

Heat pipe apparatus comprising means containing a condensable working fluid and having a vertically disposed energy input portion and an energy output portion, the energy output portion including a condenser portion in which the working fluid condenses to release heat, the condensed working fluid returning to the energy input portion for vaporization by energy applied to the input portion externally thereof, the energy input portion comprising: primary evaporator means comprising a tubular member sealed at one end and open at its other end for containing at least a portion of the working fluid, at least a portion of the working fluid being vaporized therein; and auxiliary evaporator means comprising a tubular sleeve disposed in concentrically spaced relationship about the open end of the tubular member, said tubular sleeve having a closed end portion sealed to the outer wall surfaces of the tubular member whereby a condensate receiving space is defined between the inner wall surfaces of the tubular sleeve and the outer wall surfaces of the tubular member, and the other end of said tubular sleeve extending upwardly of the open end of the tubular member and being in communication with said condenser portion for containing a portion of the working fluid and being disposed between the condenser portion and the primary evaporator means, said auxiliary evaporator means being so constructed and so arranged relative to said primary evaporator means that all of the condensed working fluid returning to the energy input portion enters the auxiliary evaporator means prior to return of a portion thereof to the primary evaporator means, said auxiliary evaporator including a heat producing means for supplying heat thereto.