Showing papers on "Heat pipe published in 1970"

Switchgear having heat pipes incorporated in the disconnecting structures and power conductors

Abstract: The primary disconnecting contacts of a metal-clad switchgear unit has at least one, and preferably two, heat pipes incorporated in the structure thereof. The use of one or more heat pipes conducts the heat generated adjacent the point of contact separations, and removes it to a remote area, at which heat sinks may be readily provided to more easily dissipate the heat generated at the separable contact structure. The advantage results that a cheaper material, such as aluminum, of small cross-sectional area, may be utilized instead of a solid copper disconnecting contact structure or higher currents may be carried where large conductors are restricted by available space. Suitable finned structures may be associated with the one or more heat pipes to serve as heat-sink structures. Also, where power conductors pass through locations, where radial heat flow is impeded, a heat pipe may advantageously be incorporated therein.

Heat pipe wick fabrication

Abstract: An economical heat pipe wick fabrication technique that yields wicks with fine pores at the liquid/vapor interface and unrestricted fluid flow beneath this interface. The resulting wick may be employed with either high or low thermal conductivity fluids.

Heat transfer surface structure

Abstract: A heat transfer surface structure is described wherein both heat and vaporizable liquid are conveyed through a capillary material to a free vaporizing surface of the capillary material where the liquid vaporizes. Heat is conducted from a heat source wall through a portion of the capillary material to the vaporizing surface where it escapes as heat of vaporization along with the vapor. The liquid flows through the pores of the capillary material from a liquid source to the vaporizing surface under the influence of capillary forces. The vaporizing surface is divided into a large number of regions which are close to the heat source wall and are connected by way of vapor passages to a region external to the capillary material. Thus, the heat conducting paths through the capillary material are very short, and vapor can escape freely through relatively large passages rather than having to force its way through the pores of the capillary material where it would interfere with the liquid flow. Such a vented capillary vaporizer is capable of handing much higher heat flux densities than previous capillary vaporizers. Four examples of capillary vaporizer are set forth, two of these for operation where the liquid and vapor are comingled as in a boiler tube or evaporator tube. One of these has separated areas of capillary material in thermal contact with the heat source surface, thereby defining passages therebetween. The other is similar with added portions of porous materials to form a manifold having a hierarchy of vapor passages of decreasing number and increasing cross section, thus increasing the separation between the regions of liquid input and vapor output. The third example accepts liquid from a capillary structure or wick as in a heat pipe, and also has a pair of manifolds in the form of a hierarchy of passages for vapor flow and capillary paths for liquid flow. The fourth example receives bulk liquid through a channel, and delivers the vapor through a separate passage. Thermal insulation maintains the bulk liquid relatively cool, and active cooling may be provided. This latter embodiment is unique in its ability to pump the heat transfer fluid since the output vapor can be at a higher pressure than the incoming bulk liquid.

Annular heat pipe

Abstract: Spaced inner and outer tubes form a closed annular chamber whose inner surfaces contain coverings of wick material that are interconnected through vane-like wicks. The wick material transports a vaporizable working fluid from cold areas where the vapor condenses to warm areas where the fluid vaporizes. An isothermal working space is produced within the central volume bounded by the inner tube and along its entire length, which may be used to advantage for oven or furnace applications or for providing an isothermal jacket.

Cooled electronic equipment mounting plate

Abstract: An electronic equipment mounting plate has capillary type heat pipes secured thereto. A condenser section is provided near the center of the plate with a coolant being passed through cooling tubes positioned adjacent the central portion of the heat pipes to provide a heat sink. In one embodiment temperature control is provided by means of a noncondensable gas and a closed end tube within the heat pipe passages adjacent the heat sink.

Sonic limitations and startup problems of heat pipes.

Abstract: Introduction of small amounts of inert, noncombustible gas aids startup in certain types of heat pipes. When the heat pipe is closely coupled to the heat sink, the startup system must be designed to bring the heat sink on-line slowly.

Steady state and transient performance of hot reservoir gas controlled heat pipes

Abstract: Liquid or vapor phase working fluids penetration effects on steady state and transient performance of hot reservoir gas controlled heat pipes

Rocket engine cooling system

Abstract: An oxidizer, such as nitrogen tetroxide or fluorine, is introduced into a reaction chamber in the path of the decomposition products of hydrazine and reacts therewith to form high temperature, high thrust propulsive gases. A heat pipe surrounds the reaction chamber and includes a wick saturated with a volatile liquid, such as liquid lithium, which liquid is vaporized thereby removing heat from the chamber wall. The vaporized fluid is directed through a heat exchanger and is therein condensed back into a liquid state.

Heat link, a heat transfer device with isolated fluid flow paths

Abstract: A heat transfer device, defined here as a heat link, having a capillary vaporizer adjacent a heat source, transfers heat to a heat sink by vaporization and condensation of a heat transfer fluid within the device. A first passage is provided for conveying vapor from the capillary vaporizer to the heat sink. Another passage which is essentially a continuation of the first passage, conveys condensed liquid from the heat sink to the vaporizer, thus allowing the distance that the liquid must flow through capillary material to be quite short. Contact of the returning liquid with the surface of the vaporizer is assured by providing means for maintaining the temperature of the liquid in the return line at a sufficiently low temperature that any vapor will condense; or, alternatively, by having means for extracting any vapor formed in the returning liquid. In this manner, the heat link operates with high heat flux without any substantial resistance to liquid flow through a long capillary flow path. By this replacing almost all of the liquid return wick, with its high resistance to fluid flow, of heat pipes with a low flow resistance liquid passage or conduit, the heat flux capacity of the heat link is greatly increased over that of the heat pipe while the quantity of porous material used and the heat link weight are considerably reduced so that a heat link typically has 10 to 1,000 times the heat flux capacity of a heat pipe having the same weight. "Boosted" embodiments of the heat link employing additional means for circulating the fluid, such as vapor jet pumps, powered at least in part by vapor from the capillary vaporizer, are also described. Some "boosted" heat links are capable of handling heat fluxes in the multi-megawatt range while having no moving parts except for check valves and the fluid itself.

Heat pipe wick restrainer

Abstract: This invention relates in general to heat pipes and more particularly to a tubular heat pipe wick restrainer which includes a tubular member with an outside diameter equal to the desired inside diameter of the wick structure. The tubular member has circumferentially placed holes which allow the heat pipe working fluid to evaporate and condense at the evaporator and condenser sections respectively.

Fluid heat transfer method and apparatus for semi-conducting devices

Abstract: There is disclosed the use of a heat pipe type thermal conductive path within a metallic housing such as a transistor can for a highly efficient cooling of high power semi-conductor devices which normally require large heat dissipation. An electrically non-conductive wick structure is provided which is formed, for example, from high purity silica glass cloth in a shape resembling a hollow ''''marshmallow'''' and which forms a liner for the entire transistor can. The wick contacts both the active surface of the semi-conductor device in the bottom of the can and the upper walls of the can. Prior to placing the can upon its mounting base, an appropriate amount of electrically nonconductive, non-polar working fluid such as high purity organic liquid is loaded so that it entirely fills or saturates only the wick like structure. The working fluid held within the wick is thus in immediate contact with the active surface of the semiconducting device. In operation, the surface of the semiconductor device serves as the evaporator section of the closed loop heat pipe. As fluid is caused to evaporate from this region, heat transfer and thus cooling of the device is effected. The vapor thus produced is recondensed over regions of the can which are at slightly cooler temperatures than the semiconductor device. The working fluid vapor thus provides an efficient heat transfer path to the entire radiating surface of the can in order to dissipate the thermal energy of concern.

Segmented heat pipe

Abstract: An improved heat pipe capable of conveying a greater heat flux than a conventional heat pipe is provided in practice of this invention. A heat pipe transfers heat from a heat source to a heat sink in the form of latent heat of vaporization of a fluid within the heat pipe. Hot vapor transfers heat from the heat source to the heat sink. Condensed liquid is returned from heat sink to the heat source through porous capillary material due to surface tension forces. The heat flux obtainable is limited by the available flow of returning liquid. In the improved heat pipe, the flow paths for liquid and vapor are serially segmented by impermeable barriers transverse to the direction of heat flow so that the distance of liquid flow in each segment is minimized. In zero gravity the heat flux obtainable is approximately proportional to the number of serial segments N into which the heat pipe is divided, that is, if the heat is transferred serially through N segments approximately N times the heat flux is possible as compared with a conventional heat pipe of the same overall dimensions. When operating against a gravity head, the maximum heat flux is about N2 times the heat flux of a conventional heat pipe. Thus a heat pipe segmented into 10 serial segments has approximately 10 to 100 times the maximum heat flux capacity of an unsegmented heat pipe of the same cross section and total length.

Hot-gas machine comprising a heat transfer device

Abstract: A hot-gas engine including a heater and a source of heat in combination with a switching device for conveying heat from the heat source to heater, the device including a pair of spaced heat pipes with third intermediate heat pipe and means for introducing inert gas into said third heat pipe and removing said gas to vary the vaporization point therein and the rate of heat transfer therethrough.

Cold-heat recovery for air conditioning

Abstract: A cold air replenishment unit for an enclosed building space comprising a purge air system, a replenish air system, a heat pipe assembly spanning the two systems to simultaneously provide cold-heat potential transfer from the purge air to the replenish air, a mechanical refrigeration system comprising the commonly known cycle components, having an air-over fin tube evaporator located downstream of the replenish air heat pipe section, and having an air-over fin tube condenser located upstream of the purge air heat pipe section, all systems jointly forming a cold-heat recovery apparatus.

Capacitor energy storage improvement by means of heat pipe

Abstract: The invention is a heat pipe coolable capacitor in which the heat generated therein and manifested in both radial and axial flow is removed by a novel arrangement of heat pipes.

Vapor discharge cell

Abstract: An electrical discharge cell having a plural wick heat pipe for preventing contamination without depleting the supply of vapor source material.

Thermal-mechanical energy transducer device

Abstract: To permit remote location of a thermal-mechanical energy transducer unit having a heat sensitive operating element, a heat pipe, such as a capillary tube containing therein a fabric, such as fiberglass fabric, and a vaporizable substance is connected in heat transfer relationship to the operating element to form a unitary device. The heat pipe having another terminal end adapted to be placed in a location where it can be heated, so that the heat pipe will upon heating of the other end above the vaporization temperature of the contents of the heat pipe, rapidly and effectively transmit heat from the source to the heat sensitive operating unit. To modify the transfer characteristics, the heat pipe may be insulated, wholly, or in part at the outside, to prevent heat loss during transmission, or to provide sharp on-off characteristics at predetermined temperatures, the temperatures being determined by the vaporization temperature of the filling of the heat pipe.

Heat pipe with dual working fluids

Abstract: In a heat pipe containing a main working fluid that normally freezes under low heat loads, an auxiliary working fluid is provided that, although being less efficient than the main working fluid, nevertheless remains liquid at low heat loads when the main working fluid freezes, so as to sustain heat pipe action.

Method and apparatus for processing vitreous melt

Abstract: A melt of vitreous material is heated uniformly by means of a heat tube or heat pipe, wherein circulation of a heat-exchange medium is effected independently of gravitational forces and exclusively as a function of a temperature differential existing within the heat tube. Various apparatus for accommodating and extruding melt of vitreous material are disclosed, and utilize the heat tube in different forms for controlling the temperature of the melt in desired manner.

Method of fabricating a heat pipe

Abstract: A tube is provided having a plurality of closely spaced very thin longitudinal fins projecting into its interior. The tube is particularly useful as a heat pipe, the capillaries defined between adjacent fins serving as a wicking structure for conveying a heat transfer working fluid from one region of the pipe to another by capillary pumping. Fabrication of the internally finned tube is accomplished by a sacrificial mandrel method.

The experimental design and operation of a rotating wickless heat pipe

Abstract: : An experimental rotating wickless heat pipe apparatus was designed and machined. The apparatus includes a rotating heat pipe assembly, test stand, spray cooling assembly, safety shielding, and instrumentation. A revised condensing limit for the operation of the rotating heat pipe was obtained by modifying Ballback's Nusselt film condensation theory to include the effects of a thermal resistance in the condenser wall and in the condenser outside surface cooling mechanism. Approximate results, obtained for half-cone angles of 1, 2, and 3 degrees, show that less heat can be removed than originally predicted by Ballback, and that the outside heat transfer coefficient can significantly alter the condensing limit. An improved Nusselt theory was developed which applies for all half-cone angles, and which includes the effects of the thermal resistances in the condenser wall and in the condenser outside surface cooling mechanism. This formulation led to a second-order non-linear differential equation for the film thickness which was numerically integrated using a free-overfall boundary condition at the condenser exit. Results obtained for a half-cone angle of 0 degrees are substantially less than the results obtained from the approximate solution for half-cone angles of 1, 2, and 3 degrees.

Closed cycle vapor engine

Abstract: A closed cycle vapor engine has evaporator and condensor elements utilizing liquid carrying wick means arranged to provide surfaces for the evaporation and condensation of the engine working fluid and to transport said fluid in liquid form from the condensor to a condensate pump and from the condensate pump to the evaporator. Vapor passages connect the evaporator and condensor with the intake and exhaust openings of the expander, providing a closed system in which the evaporator and condensor operate essentially on the principle of a heat pipe.

Applications of heat pipes to nuclear reactor engineering

Abstract: 1970 Signature was redacted for privacy.