A heat pipe has at least one liquid flow channel and one vapor flow channel for the movement of the heat carrier fluid from the evaporator end to the condenser end and vice versa. The liquid flow channel is so constructed that the capillary radius of its cross-sectional area increases from the evaporator end to the condenser end of the heat pipe, preferably in a continuous manner. Further, the evaporator end of the pipe is provided with a closure member for communicating the liquid flow channel with the vapor flow channel for replenishing the liquid in the evaporating end if necessary. Opening of the closure member also permits gas and/or vapor bubbles that have been collected in the liquid flow channel to pass into the vapor channel. The closure member may be operated by an electromagnetic valve.
The invention relates to heat engineering, in particular to heat pipes and can be used for removing heat from miniature high-heat object, in particular elements of radiotechnical instruments and computers requiring efficient removal of heat and minimum dimensions of a cooling system, the aim of said invention is to increase the heat load of an evaporation chamber at a predetermined temperature and to reduce the dimensions thereof. The inventive evaporation chamber for a loop heat pipe comprises a body having a side and an end wall and a capillary-porous orifice provided with steam-outlet channels and arranged inside said chamber. Said steam-outlet channels are united with the aid of a steam header and disposed on the part of the orifice perimeter of the side of a heat sink. Said evaporation chamber is also provided with an asymmetric hold offset in a direction opposite with respect to the heat sink. The ends of the steam-outlet channels are embodiment in such a way that they are dead on one side thereof. The asymmetric hole is also embodiment in such a way that it is dead on the side thereof which is opposite to the dead ends of the steam-outlet channels, the steam header being formed by one wall of the body and the end of the orifice.
A heat spreading apparatus includes a first planar body for attachment to a heat generating surface which results in a hot region and a cool region on the first planar body. A second planar body connected to the first planar body is used to define a void between the first planar body and the second planar body. The void includes a planar capillary path and a non-capillary region. A fluid positioned within the void distributes heat by vaporizing the fluid from the planar capillary path in the hot region, condensing the fluid in the non-capillary region in the cool region, and moving from the non-capillary region to the planar capillary path in the hot region through capillarity.
