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Publication numberUS3229759 A
Publication typeGrant
Publication dateJan 18, 1966
Filing dateDec 2, 1963
Priority dateDec 2, 1963
Also published asDE1264461B
Publication numberUS 3229759 A, US 3229759A, US-A-3229759, US3229759 A, US3229759A
InventorsGeorge M Grover
Original AssigneeGeorge M Grover
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Evaporation-condensation heat transfer device
US 3229759 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Jan. 18, 1966 G. M. GROVER I 3,229,759

EVAPORATION-CONDENSATION HEAT TRANSFER DEVICE Filed Dec. 2, 1963 2 Sheets-Sheet 1 eoo WATTS,

500 A L C 4 w w 900 [L] D: F. 600 I LL] 0. 2 500 LL] HEATED UNHEATED 300 I I I 1 l 0 1o so so so so INVENTOR DISTANCE (CM) George M. Grover Jan. 18, 1966 G. M. GROVER 3,229,759

EVAFORATION-CONDENSATION HEAT TRANSFER DEVICE Filed Dec. 2, 1963 2 Sheets-Sheet 2 Fig. 3

INVENTOR. George M. Grover BY .4../m A

United States Patent 3,229,759 EVAPORATION-CONDENSATIGN HEAT TRANSFER DEVltCE George M. Grover, Los Alamos, N. Mex., assignor to the United States of America as represented by the United States Atomic Energy Commission Filed Dec. 2, 1963, Ser. No. 327,559 3 Claims. (Cl. 165-105) This invention relates to structures of very high thermal conductance and, more particularly, to devices for the transfer of a large amount of heat with a small temperature drop, thereby being equivalent to a material having a thermal conductivity exceeding that of any known metal by a very large factor. The invention described herein was made in the course of, or under, a contract with the US. Atomic Energy Commission.

It is a desirable objective in substantially all heat transfer. applications to transfer a maximum amount of heat with a minimum temperature drop. For example, if

heatis to be transferred by radiation, it is desirable that the temperature at this place be as high as possible since therate of emission of radiant energy from the surface of abody is a function of the temperature to the fourth ,power.

The evaporation of a liquid, transport of the vapor through a duct, and subsequent condensation is a wellknown method for the transfer of a large amount of heat with a small temperature drop. In order to work continuously, the condensate must be returned to the evaporator. Ordinarily this is done by gravity or with a pump.

The present invention is a device in which this funcrtion is accomplished by a wick of suitable capillary structure. Devices of this general class will hereinafter be referred to as heat pipes, although it should be kept in mind that the shape of the device is not a matter for concern. Within certain limitations on the manner of use, a heat pipe may be regarded as a synergistic engineering structure which is equivalent to a material having a thermal conductivity greatly exceeding that of any known metal.

Accordingly, the invention is a heat transfer device comprising a container, said container enclosing a condensable vapor and capillary means within the container capable of causing the transport of the condensed vapor from a cooler area of the container to a hotter area. The transport of the vapor through the container uses, as the driving force, the difference in vapor pressures in the high temperature zone and cold temperature zone. The liquid which condenses in the cold zone is returned to the evaporation zone by capillary action. The forces to move fluids by capillary action are, of course, derived by the system attempting to arrive at a minimum free energy configuration,

It is an object of this invention to provide heat transfer devices having thermal conductivities exceeding that of any known metal by a very large factor.

It is a further object of this invention to transfer a relatively large quantity of heat with an exceedingly low temperature gradient.

It is another object of this invention to provide heat transfer devices which will accomplish the above 0bjectives under gravity-free conditions.

The above-mentioned and other features and objectives of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a schematic diagram of the principle of operation of a heat pipe.

FIGURE 2 represents the temperature profiles of a heat pipe representing the steady state temperatures measured at a number of input power levels.

FIGURE 3 is a cross section of an embodiment of the invention wherein the capillary material covers the entire inner surface of the container except for a portion of the condensing region.

The principle of operation of a heat pipe is shown schematically in FIGURE 1. The wick is saturated with a Wetting liquid. In the steady state, the liquid temperature in the evaporator is slightly higher than in the condenser region. The resulting difference in vapor pressure, P P O, drives the vapor from evaporator region 1 to condenser region 2. The depletion of liquid by evaporation causes the vapor-liquid interface in the evaporator to retreat into the wick surface where the typical meniscus has a radius of curvature, r equal to, or greater than, the largest capillary pore radius. The capillary represented in the drawing as a wire mesh is shown at 3. The pressure in the adjacent liquid will then be P (27 cos 0) /r where 7 is the surface tension and 0 the contact angle. In the condenser the typical meniscus assumes a radius, r which cannot exceed some relatively large radius determined by the geometry of the pipe. The pressure in the condenser liquid is then, P (2'y cos 0)/r The pressure drop available to drive the liquid through the wick from the condenser to the evaporator against the viscous retarding force is where p is the liquid density, g the acceleration of gravity, and k and h the heights of the liquid surfaces above a "reference level. This pressure drop may be made positive by choosing the capillary pore size sufficiently small. The above equation can be solved for r since the term 1/11 is so small as to be negligible. The pore radius of the capillary material should then be selected to be smaller than 1' Care should be taken to not make the pore radius too much smaller than r since for very small pores the increased viscous drag would interfere with the capillary return. It should be particularly noted that the possible case, g=0 (existent in gravity-free conditions such as space applications), is not excluded. Heat pipes will work under gravity-free conditions and even, to some extent, in opposition to gravity.

Water was used as working fluid in an initial qualitative experiment. A porous Alundum tube, 1' OD, I.D., and 12" long was inserted into a close-fittingPyrex tube. Enough water was added to saturate this wick and provide a small excess. The pressure in the tube was reduced by pumping at room temperature until the resulting boiling swept out all but water vapor from the central gas space. The tube was then sealed off. An evacuated blank of identical structure containing no water was also prepared. The heat pipe and the blank were arranged vertically side by side. Within a few minutes of the beginning of heating of the top few inches of the two tubes with an infrared lamp, the bottom of the heat pipe became and remained uncomfortably hot to the touch, while the bottom of the blank continued to stay nearly at room temperature.

In order to explore the qualitative potentialities further, a liquid sodium heat pipe was made for operation at about 1100 K. The containing tube was made of 347 stainless steel, GD, /8" I.D., and 12" long, with welded end-caps. The wick was made of -mesh 304 stainless steel screen with 0.005" diameter wires. This was formed in a spiral of five layers and fitted closely against the inner wall of the tube, leaving an ID. of /2". The pipe was loaded with 15 grams of solid sodium, evacuated to about 10* mm. Hg and sealed. When the top third of the pipe is heated by induction, the remarkably efficient heat transfer caused the heat pipe to be luminous almost to the cold end of the pipe. The 111- minous zone in the heat pipe terminates before reaching the bottom due to the relatively low thermal conductivity of the liquid sodium sump.

A second sodium heat pipe was made similar in all respects to the first except that the length was increased to 36". The sodium charge was increased to 40 grams. This heat pipe was placed in a vacuum chamber and about at one end was heated by electron bombardment from a concentric spiral filament. The data of FIGURE 2 were obtained after the pipe had been vacuum-baked at 1070 K. for two days. The vacuum baking, when using sodium as a coolant, is rather important owing to the fact that hydrogen is an impurity in sodium metal. Hydrogen is liberated in the reversible reaction NaH Na+%H AH3 -14 kcal.

The hydrogen is swept to the unheated end of the pipe by the refluxing sodium vapor. Consequently, in the hydrogen region the heat flux is accomplished by ordinary thermal conduction, mainly by the container wall and the saturated wick. This results in a rapidly decreasing temperature profile along the heat pipe. Under the vacuum baking conditions, hydrogen diffuses fairly readily through stainless steel. However, even after baking for two days, there appears to be about 5 X mole of hydrogen present at 100 watts, when the average temperature is near 500 K., increasing to 10 mole at 600 watts, when the average temperature is about 850 K. This is roughly consistent with the heat of reaction cited. Residual hydrogen occupies a volume determined jointly by the pressure of the sodium vapor in the refluxing section, and some average temperature in the non-refluxing section.

In FIGURE 2, which is a plot of the steady state temperatures measured at a number of input power levels versus the distances along the heat pipe, the region of rapidly decreasing temperature is caused by the presence of hydrogen gas. The temperature plateaus extending out from the heat region are of principal interest. This is the refluxing region. The method of measurement (five chromel-alumel thermocouples welded at intervals along the 36 pipe) was not precise enough to detect the minute temperature gradients but they do not exceed 0.05 K./ cm. In the refluxing region the heat pipe is behaving in a manner equivalent to a solid bar of material having a thermal conductivity in excess of 10 cal./sec.-cm.- K. A calculation, based on a detailed dynamic model of the heat pipe which will not be elaborated here, indicates that the actual temperature gradients are at least an order of magnitude less than this upper limit.

Attempts to deliver more than 30 watts/cm. through the surface of the heated section of the pipe resulted in the appearance of local overheated areas due either to deformation or drying of the wick. This phenomenon is probably a significant limitation on the operation of heat pipes.

Obviously, when using a coolant which does not have as an impurity a gas which is non-condensable at the temperatures of interest, the non-reflux region of rapidly decreasing temperatures will not be present. The use of sodium as a coolant may also be disadvantageous in that the corrosive sodium may, after extensive operation, dissolve the container at the place of condensation and deposit the container metal at the place of evaporation. Lithium coolant in a niobium-1% zirconium alloy would be advantageous at temperatures of about 1100 C. Lithium possesses another advantage in that its heat of vaporization is approximately 5000 caL/gram as compared to about 1000 cal/gram for sodium and about 500 cal./ gram for water. An experiment was carried out using lithium in niobium-1% zirconium alloy without a capillary path. The bottom portion of the pipe was immersed in a heat source. After proper operation for a short time the heat transfer rate went down very sharply. This was found to be due to the accumulation of lithium at the top of the pipe. The addition of a screen mesh along the inner walls of the pipe to provide a capillary flow return path allowed proper operation of this heat pipe. Tantalum and silver do not form alloys and this combination of materials would be useful at temperatures of about 2000 C. A heat pipe of tantalum with a tantalum screen and with silver as the working fluid has been operated for short times at 1700" C. The lifetime at this operating temperature has not been established. It should be noted that a range of temperatures for each coolant is possible by operating at various pressures inside the container. A range of temperatures would accordingly give a range of vapor pressures and heat transfer rates. The theoretical upper limit of temperature is the critical temperature of the circulating fluid since at that temperature the surface tension goes to zero. I

It should also be noted that the shape of the device is a matter of discretion. Hollow plates, rods, etc., are equally adaptable to the present inventive concept. Furthermore, there is no requirement that the pipe be heated at one end and condense at the other. For example, the pipe may be heated somewhere along its length and condense at both ends. Capillary material should be present at the point at which the heat transfer pipe is to be heated. However, it is not necessary that the capillary material cover the entire condensing region, only that the capillary material extend into the condenser region. This con struction is shown in FIGURE 3 wherein 1 represents the evaporator region and the condenser region is shown at 2. The material comprising the capillary path is a matter of complete discretion. For example, glass frit, wire mesh, tubes, etc., may be utilized; the only requirement being that the pore size be sufficiently small to produce capillary action. Since capillary action is utilized to return the liquid from condenser to evaporator regions, the heat pipe will work under gravity-free conditions and even, to some extent, against the force of gravity.

Since many changes can be made in the construction of a heat pipe (some of which are mentioned above) and many apparent widely diflerent embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. The invention should therefore, be limited only by the following appended claims.

What is claimed is:

1. A heat transfer device comprising a container having condenser and evaporator regions composed of niobiuml% zirconium alloy, said container enclosing a condensable vapor consisting of lithium, capillary means, said capillary means covering the entire inner surface of the container except for a portion of the condensing region, the quantity of condensable vapor present being just suflicient to saturate the capillary means when condensed and provide a small excess, said capillary means capable of causing the transport of the condensed vapor from the cooler area of the container to the hotter area.

2. A heat transfer device comprising a container having condenser and evaporator regions composed of niobium- 1% zirconium alloy, the exterior portion of said container being smooth and said container enclosing a condensable vapor consisting of lithium, capillary means, said capillary means covering the entire inner surface of the container except for a portion of the condensing region, the quantity of condensable vapor present being just sufficient to saturate the capillary means when condensed and provides a small excess, said capillary means capable of causing the transport of the condensed vapor from the cooler area of the container to the hotter area.

3. A heat transfer device comprising a container having condenser and evaporator regions composed of niobium- 1% zirconium alloy, the exterior portion of said container being smooth, said container enclosing a condensable vapor consisting of lithium, capillary means, said capillary means covering the entire inner surface of the container except for a portion of the condensing region, the quantity of condensable vapor present being just suflicient to saturate the capillary means when condensed and provide a small excess, the pore radius of the capillary material being slightly smaller than r r being defined by making the expression 'Y( '2) 2 1)-P 2 1) slightly positive, Where p is the liquid density, g the acceleration of gravity, b and 12 the heights of liquid surfaces in the evaporator and condenser regions above a reference level, 7 is the surface tension, 0 the contact angle, P and P are the vapor pressures in the evaporator and condenser regions, and r the radius of curvature of region.

References Cited by the Examiner UNITED STATES PATENTS Gaugler 6256 X Kuenhold 261-104 Gaugler 26 1--1 04 X Cornelison et al. 165105 X Chandler 261-404 X Hebeler 165-134 Wyatt 2441 ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, Examiner.

a meniscus in the capillary located at the evaporator 15 N'R'WHSONAsslSmm Exammer'

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2350348 *Dec 21, 1942Jun 6, 1944Gen Motors CorpHeat transfer device
US2394698 *Aug 7, 1942Feb 12, 1946Monmouth Products CompanyEvaporator
US2517654 *May 17, 1946Aug 8, 1950Gen Motors CorpRefrigerating apparatus
US2958021 *Apr 23, 1958Oct 25, 1960Texas Instruments IncCooling arrangement for transistor
US3043573 *Feb 16, 1956Jul 10, 1962Edward F ChandlerThermo-transpiration portable air conditioner unit
US3089318 *Jan 10, 1961May 14, 1963Boeing CoHypersonic cooling system
US3152774 *Jun 11, 1963Oct 13, 1964Wyatt TheodoreSatellite temperature stabilization system
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3302042 *Oct 23, 1965Jan 31, 1967George M GroverNuclear reactor with thermionic converter
US3305005 *Dec 3, 1965Feb 21, 1967Busse Claus ACapillary insert for heat tubes and process for manufacturing such inserts
US3378449 *Jul 27, 1967Apr 16, 1968Atomic Energy Commission UsaNuclear reactor adapted for use in space
US3378454 *Aug 22, 1966Apr 16, 1968EuratomNuclear fuel arrangement
US3399717 *Dec 27, 1966Sep 3, 1968Trw IncThermal switch
US3402761 *Feb 17, 1967Sep 24, 1968Navy UsaControllable heat pipe apparatus
US3403075 *Aug 11, 1966Sep 24, 1968EuratomNuclear reactor
US3405299 *Jan 27, 1967Oct 8, 1968Rca CorpVaporizable medium type heat exchanger for electron tubes
US3414050 *Apr 11, 1967Dec 3, 1968Navy UsaHeat pipe control apparatus
US3414475 *May 13, 1966Dec 3, 1968EuratomHeat pipes
US3426220 *Feb 16, 1966Feb 4, 1969Rca CorpHeat-sensitive seal for thermionic converters
US3435889 *Apr 25, 1966Apr 1, 1969Martin Marietta CorpHeat pipes for non-wetting fluids
US3441752 *Oct 23, 1965Apr 29, 1969Atomic Energy CommissionThermionic converter device
US3450195 *Mar 16, 1967Jun 17, 1969Gen ElectricMultiple circuit heat transfer device
US3457436 *Nov 7, 1966Jul 22, 1969Teledyne IncHeat pipes with unique radiator configuration in combination with thermoionic converters
US3464889 *Nov 1, 1967Sep 2, 1969Atomic Energy CommissionHeat actuated control rod utilizing a cadmium-potassium mixture
US3465813 *Jul 26, 1967Sep 9, 1969Trw IncMethod of and means for increasing the heat transfer capability of a heat pipe
US3468300 *Nov 13, 1968Sep 23, 1969Acf Ind IncHeat transfer means for a railway tank car
US3490718 *Feb 1, 1967Jan 20, 1970NasaCapillary radiator
US3502138 *Aug 14, 1967Mar 24, 1970Trw IncMeans for regulating thermal energy transfer through a heat pipe
US3503438 *Oct 25, 1968Mar 31, 1970Acf Ind IncHydrogen release for a heat pipe
US3509386 *Sep 6, 1967Apr 28, 1970NasaHeat pipe thermionic diode power system
US3516487 *Feb 21, 1968Jun 23, 1970Gen ElectricHeat pipe with control
US3517730 *Mar 15, 1967Jun 30, 1970Us NavyControllable heat pipe
US3524772 *Dec 3, 1964Aug 18, 1970Nuclear Materials & EquipmentGenerator of electrical energy
US3525670 *Dec 17, 1968Aug 25, 1970Atomic Energy CommissionTwo-phase fluid control system
US3541487 *Nov 18, 1968Nov 17, 1970Westinghouse Electric CorpElectrical winding having heat exchangers between layers of the winding for cooling the windings
US3561525 *Jul 2, 1969Feb 9, 1971Energy Conversion Systemes IncHeat pipe condensate return
US3563309 *Sep 16, 1968Feb 16, 1971Hughes Aircraft CoHeat pipe having improved dielectric strength
US3568762 *May 23, 1967Mar 9, 1971Rca CorpHeat pipe
US3585842 *May 12, 1969Jun 22, 1971Phillips Petroleum CoMethod and apparatus for temperature control
US3595304 *Sep 15, 1967Jul 27, 1971Monsanto CoOrganic fluids for heat pipes
US3603382 *Nov 3, 1969Sep 7, 1971NasaRadial heat flux transformer
US3603767 *Sep 3, 1969Sep 7, 1971Dynatherm CorpIsothermal cooking or heating device
US3604503 *Aug 2, 1968Sep 14, 1971Energy Conversion Systems IncHeat pipes
US3613773 *Dec 7, 1964Oct 19, 1971Rca CorpConstant temperature output heat pipe
US3613774 *Oct 8, 1969Oct 19, 1971Sanders Associates IncUnilateral heat transfer apparatus
US3621906 *Sep 2, 1969Nov 23, 1971Gen Motors CorpControl system for heat pipes
US3651240 *Jan 31, 1969Mar 21, 1972Trw IncHeat transfer device
US3651861 *Jan 15, 1970Mar 28, 1972GoetzewerkeMold and method
US3662137 *Jan 21, 1970May 9, 1972Westinghouse Electric CorpSwitchgear having heat pipes incorporated in the disconnecting structures and power conductors
US3670495 *Jul 15, 1970Jun 20, 1972Gen Motors CorpClosed cycle vapor engine
US3672443 *Jan 28, 1969Jun 27, 1972Teledyne IncThermal control and power flattening for radioisotopic thermodynamic power system
US3677329 *Nov 16, 1970Jul 18, 1972Trw IncAnnular heat pipe
US3688838 *Aug 24, 1970Sep 5, 1972Bbc Brown Boveri & CieHeat tube
US3699343 *Aug 19, 1969Oct 17, 1972Sanders Associates IncCondensation heated black body radiation source
US3712053 *Apr 27, 1970Jan 23, 1973S KofinkThermal-mechanical energy transducer device
US3763838 *Dec 23, 1971Oct 9, 1973Shell Oil CoCarburetor having a heat pipe for vaporizing fuel
US3786861 *Apr 12, 1971Jan 22, 1974Battelle Memorial InstituteHeat pipes
US3788388 *Feb 19, 1971Jan 29, 1974Q Dot CorpHeat exchange system
US3788389 *Aug 25, 1971Jan 29, 1974Mc Donnell Douglas CorpPermafrost structural support with heat pipe stabilization
US3834457 *Jan 17, 1973Sep 10, 1974Bendix CorpLaminated heat pipe and method of manufacture
US3853112 *Feb 16, 1973Dec 10, 1974Thermo Electron CorpVapor transfer food preparation and heating apparatus
US3854524 *Sep 7, 1972Dec 17, 1974Atomic Energy CommissionThermal switch-heat pipe
US3889096 *Feb 22, 1973Jun 10, 1975Philips CorpElectric soldering iron delivering heat by change of state of a liquid heat transporting medium
US3921710 *Aug 22, 1973Nov 25, 1975Tokico LtdHeat pipe and manufacturing method thereof
US4005297 *Oct 18, 1972Jan 25, 1977Westinghouse Electric CorporationVacuum-type circuit interrupters having heat-dissipating devices associated with the contact structures thereof
US4108239 *Mar 22, 1976Aug 22, 1978Siemens AktiengesellschaftHeat pipe
US4273100 *Feb 16, 1979Jun 16, 1981W. R. Grace & Co.Passive solar heating and cooling panels
US4282926 *Feb 22, 1979Aug 11, 1981James Howden And Company Australia Pty. LimitedCooling of fluid streams
US4294659 *Jan 16, 1978Oct 13, 1981United Kingdom Atomic Energy AuthorityApparatus for use in a liquid alkali metal environment
US4320246 *Jul 19, 1979Mar 16, 1982Russell George FUniform surface temperature heat pipe and method of using the same
US4413475 *May 14, 1982Nov 8, 1983Moscrip William MThermodynamic working fluids for Stirling-cycle, reciprocating thermal machines
US4452298 *Mar 23, 1982Jun 5, 1984Mannesmann AktiengesellschaftMethod and apparatus for cooling continuously cast metal strands
US4478784 *Jun 10, 1982Oct 23, 1984The United States Of America As Represented By The United States Department Of EnergyPassive heat transfer means for nuclear reactors
US4485670 *Feb 13, 1981Dec 4, 1984The United States Of America As Represented By The Administrator Of The National Aeronautics And Space AdministrationHeat pipe cooled probe
US4526533 *Sep 29, 1982Jul 2, 1985A. Monforts Gmbh & Co.Cylinder for guiding a web of textile material
US4560533 *Aug 30, 1984Dec 24, 1985The United States Of America As Represented By The United States Department Of EnergyFast reactor power plant design having heat pipe heat exchanger
US4582121 *Sep 16, 1980Apr 15, 1986Casey Charles BApparatus for and method of heat transfer
US4681995 *Apr 4, 1986Jul 21, 1987Ahern Brian SHeat pipe ring stacked assembly
US4697205 *Mar 13, 1986Sep 29, 1987Thermacore, Inc.Heat pipe
US4854378 *Oct 27, 1986Aug 8, 1989Zappia Joseph MHeat transfer and fluid heating device
US5002122 *Sep 25, 1984Mar 26, 1991Thermacore, Inc.Tunnel artery wick for high power density surfaces
US5947111 *Apr 30, 1998Sep 7, 1999Hudson Products CorporationApparatus for the controlled heating of process fluids
US7168480 *Apr 29, 2004Jan 30, 2007Los Alamos National Security, LlcOff-axis cooling of rotating devices using a crank-shaped heat pipe
US7306654Jan 30, 2004Dec 11, 2007Ronald KingMethod and apparatus for recovering water from atmospheric air
US7828046Jul 20, 2005Nov 9, 2010Xiao HuangHybrid wicking materials for use in high performance heat pipes
US7957708Mar 2, 2005Jun 7, 2011Rosemount Inc.Process device with improved power generation
US8145180Sep 27, 2005Mar 27, 2012Rosemount Inc.Power generation for process devices
US8188359Sep 28, 2006May 29, 2012Rosemount Inc.Thermoelectric generator assembly for field process devices
US8538560May 21, 2004Sep 17, 2013Rosemount Inc.Wireless power and communication unit for process field devices
US8626087Aug 27, 2010Jan 7, 2014Rosemount Inc.Wire harness for field devices used in a hazardous locations
US8694060Jun 16, 2009Apr 8, 2014Rosemount Inc.Form factor and electromagnetic interference protection for process device wireless adapters
US8787848Jun 17, 2009Jul 22, 2014Rosemount Inc.RF adapter for field device with low voltage intrinsic safety clamping
US8827498 *Sep 30, 2008Sep 9, 2014Osram Sylvania Inc.LED light source having glass heat pipe with fiberglass wick
US8847571Jun 17, 2009Sep 30, 2014Rosemount Inc.RF adapter for field device with variable voltage drop
US8929948Jun 16, 2009Jan 6, 2015Rosemount Inc.Wireless communication adapter for field devices
DE2602211A1 *Jan 22, 1976Aug 5, 1976Philips NvWaermeaustauscher
DE102013014988A1Sep 7, 2013Mar 26, 2015Messer Austria GmbhBrenner
EP2846092A2Sep 5, 2014Mar 11, 2015Messer Austria GmbHBurner
WO2003071215A1Sep 13, 2002Aug 28, 2003John GruzleskiHeat pipe
Classifications
U.S. Classification165/104.26, 165/905, 376/367, 174/15.1, 62/513, 62/487
International ClassificationG21C15/02, F28D15/04, G21C15/257
Cooperative ClassificationY02E30/40, G21C15/02, F28D15/04, G21C15/257, Y10S165/905
European ClassificationF28D15/04, G21C15/02, G21C15/257