Showing papers on "Heat pipe published in 1982"

Physical principles of heat pipes

Abstract: Heat pipes are used whenever high rates of heat transfer or the control or conversion of heat flows are required. This book covers the physical principles of operation of heat pipes and choice of working fluid related to temperature range. The authors demonstrate how performance is limited by capillary pumping action in the wick together with impedance to liquid and vapor flow between the evaporator and condenser, sonic conditions, entrainment, evaporation and condensation rates.

The physical principles of heat pipes

Abstract: Heat pipes are used whenever high rates of heat transfer or the control or conversion of heat flows are required. This book covers the physical principles of operation of heat pipes and choice of working fluid related to temperature range. The authors demonstrate how performance is limited by capillary pumping action in the wick together with impedance to liquid and vapor flow between the evaporator and condenser, sonic conditions, entrainment, evaporation and condensation rates.

Cooling apparatus for a closed housing

Abstract: A cooling apparatus for a housing which is provided with an opening at the upper part thereof, comprises a casing located on the upper part of the housing and including a bottom plate to close the opening and a chamber, a partition wall provided in the casing to divide the chamber into a first chamber section and a second chamber section, heat exchanger including at least one heat pipe provided in the casing through the partition wall with coolant therein for exchanging heat in the first chamber section with heat in the second chamber section. The heat pipe has one end portion in the first chamber section and the other end portion in the second chamber section, and inclines with the one end portion located lower than the other end portion.

Thermoelectric systems incorporating rectangular heat pipes

Abstract: The present invention provides a low cost, compact, efficient thermoelectric system which has no moving parts for converting waste heat into electrical energy. The system includes a plurality of heat pipes having at least one substantially planar sidewall and integral heat collecting fins. The planar sidewalls on the heat pipes enable broad surface thermal contact with thermoelectric devices. The heat pipes and integral heat collecting fins provide for the efficient collection and transmission of waste heat to the side of the thermoelectric devices contacting the heat pipes at a location outside of the flow of waste heat. The other side of each thermoelectric device is either water or air cooled to establish a temperature differential thereacross for the generation of electrical energy. The heat pipes are preferably generally rectangular in cross section to provide opposed substantially planar surfaces for making efficient, low heat loss, broad surface thermal contact with the thermoelectric devices.

Heat pipe having multiple integral wick structures

Abstract: This invention relates generally to the field of heat pipes, and is specifically concerned with an internal wicking structure to promote the capillary flow of a system liquid from the condensor section to the evaporator section, such that the evaporator section is uniformly saturated. This phenomena is achieved through the use of multiple diverse wicking patterns, formed integrally in the interior walls of the heat pipe.

Injection molding method

Abstract: A novel method and device for precision injection molding is disclosed providing controlled cooling of a portion of the mold cavity surface during the molding cycle, or several such portions independently, and also, in the preferred embodiment controlled heating of a portion of the mold cavity surface during the molding cycle or several such portions independently, whereby high quality, high precision parts having close dimensional tolerances may be produced. Another aspect of the invention, a volume-controlled variable conductance heat pipe is disclosed, which novel heat pipe comprises housing means forming a sealed chamber, fluid, such as water or ammonia, within the chamber, wicking means and control means for controlling the thermal conductance of the heat pipe comprising means for controlling the volume of fluid in the liquid phase in the chamber. Preferably, the novel injection mold comprises a thin mold face supported at least in part by a foundation means which either incorporates, or is itself, a novel volume controlled variable conductance heat pipe as disclosed.

Plated heat pipe

Abstract: A heat pipe formed by metal deposition, on porous metal wick parts, which forms the enclosure and provides both a metallurgical bond to the wick and a hermetic seal.

Heat pipe heat exchanger

Abstract: Being a heat pipe heat exchanger wherein a group of heat pipes are arranged in box form and the central part thereof is partitioned, a high temperature fluid being let to flow into one and a low temperature fluid into the other one, respectively, so that, by the specific properties of the heat pipes, the heat given from the high temperature fluid is transferred to the low temperature fluid through the sealed-in fluid in the heat pipes, a plurality of heat pipes of which those on at least the high temperature fluid passage side are bare pipes are arranged to extend over both passages, and the heat pipes on the high temperature fluid passage side are inserted in finless outer pipes. At least the outer surface of these finless outer pipes is treated for resistance to corrosion. Also, these finless outer pipes and the heat pipes are joined by a heat conductive material, so that heat pipes can be easily demounted, and, therefore, the efficiency of the heat exchanger can be varied as required.

Waste heat recovery system having thermal sleeve support for heat pipe

Abstract: A system for recovering waste heat from a stream of heated gas is disclosed The system includes a convection heat transfer chamber, a boiler tank, and a plurality of heat pipes thermally interconnecting the convection heat transfer chamber with the boiler tank Each of the heat pipes includes an evaporator section which is disposed in heat transfer relation with a stream of heated gas flowing through the convection heat transfer chamber, and a condenser section disposed in heat transfer relation with a volume of water contained within the boiler tank The boiler tank is provided with a header plate having an array of heat pipe openings through which the heat pipes project A heat pipe support sleeve is received in each heat pipe opening in sealed engagement with the header plate, with the heat pipes projecting through the support sleeves and thermally interconnecting the convection heat transfer chamber with the boiler tank An intermediate portion of each heat pipe is received in sealed engagement with its associated support sleeve In a preferred embodiment, heat transfer through the support sleeve is minimized in an arrangement in which each heat pipe opening is reduced by a stepped bore with the support sleeve connected in threaded, sealed engagement with the stepped bore Furthermore, in this arrangement, the support sleeve has swaged end portions which project beyond the header plate and engage the heat pipe on opposite sides at points which are remote with respect to the support sleeve/header plate interface One of the swaged end portions is sealed against the heat pipe in a fluid-tight union within the boiler tank The support sleeve is radially spaced with respect to the heat pipe, and is also radially spaced with respect to the heat pipe opening whereby heat transfer through the walls of the heat pipe to the support sleeve and to the header plate is minimized by concentric annular air gaps

Passive heat transfer means for nuclear reactors

Abstract: An improved passive cooling arrangement is disclosed for maintaining adjacent or related components of a nuclear reactor within specified temperature differences. Specifically, heat pipes are operatively interposed between the components, with the vaporizing section of the heat pipe proximate the hot component operable to cool it and the primary condensing section of the heat pipe proximate the other and cooler component operable to heat it. Each heat pipe further has a secondary condensing section that is located outwardly beyond the reactor confinement and in a secondary heat sink, such as air ambient the containment, that is cooler than the other reactor component. Means such as shrouding normally isolated the secondary condensing section from effective heat transfer with the heat sink, but a sensor responds to overheat conditions of the reactor to open the shrouding, which thereby increases the cooling capacity of the heat pipe. By having many such heat pipes, an emergency passive cooling system is defined that is operative without electrical power.

Heat pipe thermal switch

Abstract: A thermal switch for controlling the dissipation of heat between a body (20), acting as a heat source, and a heat sink (22). The thermal switch is comprised of a flexible bellows (12) defining an expansible vapor chamber for a working fluid located between an evaporation and condensation chamber (16, 14). Inside the bellows (12) is located a coiled retaining spring (54) and four axial metal mesh wicks (46, 48, 50, 52) two of which (46, 48) have their central portions located inside of the spring (54) while the other two (50, 52) have their central portions located between the spring (54) and the side wall of the bellows (12). The wicks are terminated and are attached to the inner surfaces (56, 58) of the outer end walls (60, 62) of evaporation and condensation chambers (14, 16) respectively located adjacent the heat source (20) and heat sink (22). The inner surfaces of the end walls furthermore include grooves (64, 66) to provide flow channels of the working fluid to and from the wick ends. The evaporation and condensation chambers are connected by turnbuckles (30, 31, 32) and tension springs (26, 27, 28) to provide a set point adjustment for setting the gap (24) between an interface plate 18 on the condensation chamber (14) and the heat sink (22).

Improvements in or relating to heat pipes

Abstract: A heat pipe assembly, principally an assembly including a heat pipe in the form of a conformable garment acting as a heat receiver or cooling element, and wherein the liquid return to the heat pipe is actively pumped, thus permitting remoting of receiver and sink with minimum assembly bulk, and independance of geometrical configuration require­ ments.

Wet/dry steam condenser

Abstract: A wet/dry steam condenser in accordance with the present invention includes two spaced-apart, vertically aligned groups of heat pipes with each group having the lower, evaporator sections of their respective heat pipes exposed to the interior of an associated, longitudinally extending steam-receiving plenum. The upper, condensing section of each heat pipe is provided with fin structures and can be selectively cooled by a fan-induced air flow and/or deluge water supplied from either a flood water trough and/or a spray-head assembly.

The Development of Economical Rotating Heat Pipes

Abstract: In this experiment, a rotating heat pipe was constructed with a single evaporator section but with several commercially available cylindrical condenser sections. Tests were made with cylinders having smooth walls, straight axial fins, spiralled fins, and helical corrugations. Heat transfer measurements were taken at rotational speeds of 700, 1400 and 2800 RPM using distilled water, ethyl alcohol and Freon-113 as working fluids. Results show that the commercially available cylinders can be used effectively in place of more costly condensers manufactured with tapered walls. A comparison of heat transfer performance is provided.

Hybrid heat pipe

Abstract: A heat pipe constructed to be bent to conform to a particular mechanical configuration after is is constructed. The wick in the evaporator region is constructed from sintered metal powder; while the wick in another region of the heat pipe is constructed with a screen wick to permit bending the pipe without destruction of the wick. Arteries wound from flexible screen material are continuous through both the sintered wick, into which they are inserted, and the screen wick, to which they are also attached.

Radiant/conductive broiler

Abstract: A broiler for cooking food products has an upper heating unit located in a spaced relationship from the food and a lower heating unit in a close heat transfer relationship with the food. The upper unit is preferably a U-shaped radiant fire tube with a gas-fired power burner mounted at one end as a heat source. Hot flue products exiting the radiant tube are directed to the lower heating unit which is preferably a heat pipe assembly with evaporator and condenser zones for a working fluid. In one form the condenser zone includes a generally flat wall portion with a cooking surface defining a set of upwardly facing grooves. In another form the condenser zone is a series of generally parallel pipes that extend under the food in a horizontal, mutually spaced relationship. A movable rack supports the food and moves it into and out of a cooking relationship with the condenser zone of the heat pipe assembly.

Surface heater structure, especially for vehicles

Abstract: A surface heater body which is constructed as two-layer, expanded partial composite laminated body and contains two mutually separated channels or channel systems adjoining one another wall-to-wall in a heat-conducting manner; one channel system which extends over the entire area of the surface heater body and which is hermetically closed off, operates as heat-pipe to distribute the supplied heat over a large area; a heat channel traversed by heating water extends along the bottom edge of the surface heater body; a rectilinear continuous non-expanded strip is provided between the heat channel and the heat-pipe channel system, along which the partial composite laminated body is bent U-shaped so that the heat channel and the heat-pipe channel system come into mutual abutment where they are permanently and heat-conductingly connected with each other over the entire contact surface; a separate pipe may also be provided as heat channel or, as a still further alternative, a heat-pipe may be inserted into the heat-pipe channel system whereby the two edges of the surface heater body are sealed off at the places where the heat pipe leaves the heater element.

Fluidized bed reactor system

Abstract: A fluidized bed reactor system for introducing heat energy into or removing heat energy from fluidized reactants undergoing reaction includes, in a first embodiment, a fluidized bed reactor for fluidizing a particulate material in a fluidizing medium and a heat generator for supplying heat energy to the fluidized bed. A plurality of heat pipes interconnect the heat generator and the fluidized bed reactor with the evaporator portions of the heat pipes extending into the heat generator and the condenser portions thereof extending into the fluidized bed. Thermal energy from the heat generator is absorbed by the evaporator portions of the heat pipes and conveyed through the heat pipes to the condenser portions where the thermal energy is transferred to the fluidized bed. Since heat pipes transfer thermal energy at a relatively constant temperature throughout a wide range of thermal flows, heat energy can be introduced into endothermic fluidized reactions at a relatively constant temperature to achieve preferred reaction rates. In a second embodiment, the evaporator portion of the heat pipes extend into the fluidized bed and the condenser portions extend outwardly of the fluidized bed to a heat sink.

Improvements in heat pipes

Abstract: A flat, flexible or conformable heat pipe assembly usable in conditioning clothing and other heat transfer situations. It has a reticulated structure including wicking and void continua, an impermeable plastics film or laminate envelope surrounding the structure and a valve in the assembly by which the assembly may be outgassed and evacuated and liquid introduced thereinto.

Thermal control system

Abstract: A variable, thermal control system (10) for regulating the temperature of an exothermic process plant carried aboard an earth orbiting spacecraft is made with a plurality of curved radiator panels (14) arcuately positioned in a circular arrangement to form an open receptacle. A module (12) containing the process is insertable into the receptacle. Heat exchangers (42) having broad exterior surfaces (43) extending axially above the circumference of the module (12) fit within arcuate spacings (18) between adjacent radiator panels (14). Banks of variable conductance heat pipes (24) partially embedded within and thermally coupled to the radiator panels (14) extend across the arcuate spacings (18) and are thermally coupled to broad exterior surfaces (43) of the heat exchangers by flanges (26). Temperature sensors (86) monitor the temperature of process fluid flowing from the module through the heat exchanges. Thermal conduction between the heat exchangers (42) and the radiator panels is regulated by heating a control fluid within the heat pipes to vary the effective thermal length of the heat pipes (24) in inverse proportion to changes in the temperature of the process fluid.

Solar heat collector

Abstract: PURPOSE:To obtain the solar heat collector, excellent in heat collecting capacity and not producing thermal stress readily, by a method wherein a hollow plate-like body, consisting of extruded member, is used as a heat collecting body and heat medium, not spoiling the extruded material, is accommodated in the evacuated hollow body to use them as a heat pipe. CONSTITUTION:One end of the heat collecting body 4, formed into the hollow plate-like form by extruding work, is accommodated in the outer tube 1 of glass, which is kept in vacuum, and the other end thereof is taken out of the outer tube 1. The heat medium such as Freon or the like, which effects heat pipe effect and not spoiling the extruded member, is sealed int he hollow section of the heat collecting body 4, the hollow section in devided into a plurality of paths widthwise by partitioning walls 5 so as to form heat medium paths 6, 7 and the part of the heat collecting body 4 in the outer tube 1 is utilized as heating and evaporating section while the end of the heat collecting body 4, which is taken out of the outer tube 1, is connected to a body 10 to be heated so as to form a heat exchanging and condensing section 9. As a result, corrosion of the extruded form will never be generated, the partitioning walls 5 prevent the deformation of the heat collecting body and the deformation due to external forces, not to mention thermal strain and deformation, may be prevented.

Heat Transfer Characteristics of Disk-Shaped Rotating, Wickless Heat Pipe

Abstract: The disk-shaped rotating heat pipe is a sealed hollow disk, and containing a fixed amount of working fluid. Rotation about the center axis of the disk generates a centrifugal force field and a component of this force along the tapered wall pump the condensate back to the evaporator. A theoretical analysis is proposed for laminar film condensation on the inside of a rotating hollow disk which includes the drag effect of contra flowing vapor. Experimental investigation tests the analysis with good agreement for the ethyl alchol fluid.

Heat pipe type solar heat water heater

Abstract: PURPOSE:To improve the heat exchange efficiency of the heat pipe with respect to water in a hot water storage tank by a method wherein the hot water storage tank of a large capacity is divided into a plurality of sub-tanks of small capacity so that the heat exchange between a condensing section of the heat pipe and the water is performed within the sub-tanks. CONSTITUTION:The sunlight passed through a glass body 10 boils an operating liquid at an evaporation section 3a within the heat pipe 3. In this case, the latent heat of evaporation of the operating liquid is adsorbed at the evaporation section 3a and is discharged at the condensing section 3b to thereby heat the water 5 in the sub-tanks 11. Thus, when the water 5 in the sub-tanks is heated to a high temperature, the specific gravity of the water becomes small so that the water flows into the hot water storage tank 2 from a forward pipe 13 and an inlet port 15 through a hose 17 due to a convection phenomenon. At the same time, the low temperature hot water in the tank 2 passes through a hose 18 from an outlet port 6 and flows into the sub-tanks 11 from a return port 14.

External artery heat pipe

Abstract: An improved heat pipe (115) of increased heat transport capacity comprising a vapor tube (120) and a liquid-condensate return tube (130). An outwardly extending conduit (125), disposed in both the evaporator section (135) and evaporator section (140) of the heat pipe (115), provides fluid communication between the vapor tube (120) and the return tube (130). Circumferential v-shaped grooves (145) terminate at a slot-like opening (165) formed in each of the conduits (125). A cap member (170) traverses each opening (165) and coacts with the grooves (145) to form a plurality of fluid passageways (175).

Dry etching device

Abstract: PURPOSE:To improve cooling effect by a method wherein heat pipes are embedded into a lower electrode of parallel flat plate electrodes to control the vapor pressure of working fluid in the heat pipes so as to cool the silicon substrate corresponding to the changes of etching conditions. CONSTITUTION:A plurality of heat pipes 13 are embedded into a lower electrode 6 and the vapor pressure of working fluid in the heat pipes 13 is controlled to increase the cooling capacity of the heat pipes 13 corresponding to the change of etching condition by means of a signal converter 14 cooling a silicon substrate 2 to perform etching operation. In case of etching a film formed on the substrate 2 into specified pattern, the film on the substrate 2 is preliminarily coated with resist 4 to form a mask pattern. Then the substrate 2 is placed on an electrode 6 in a chamber 11 which is kept under prescribed pressure by means of an oil rotary pump 10 and an oil diffusion pump 9 supplying the chamber with reaction gas to generate plasma.

Thermally powered heat transfer systems

Abstract: A thermally powered heat transfer system consisting of two closed heat transfer loops which share a compressor which is alternately powered by the refrigerants of the two loops. This system is powered by two heat sources having different temperatures of which the lower temperature heat source may be the heat within a structure to be cooled. An evaporator of the first loop located within the structure to be cooled is charged with a low boiling point refrigerant while an evaporator of the second loop is heated by a higher temperature heat source and is charged with a higher boiling point refrigerant. The heat sinks of the loops are at temperatures between those of the two heat sources. Controls are activated at the completion of each compressor stroke, or cycle, to alternately open and close valves which regulate vapor and liquid flows to cause the compressor to act with compressive force upon one or the other refrigerant vapor during each cycle of operation of the system to effect useful heat transfer.