PSAR Report

Patent Search and Analysis Report (PSAR) Reports

submitted as a part of the

PROJECT REPORT

“An Experimental and Theoretical Analysis of Heat Pipes”

Submitted by

In partial fulfillment for the award of the degree

of

BACHELOR OF ENGINEERING In

MECHANICAL ENGINEERING

C. G. PATEL INSTITUTE OF TECHNOLOGY,

BARDOLI.

Gujarat Technological University

Ahmedabad

December, 2013

Sr.

No. NAME

ENROLLMENT

NO. BATCH

1 DALAL RUSHABH M. 100530119034 B.E.

MECH.

VIIth

2 PATEL KAUSHAL S. 110533119011

3 KABRAWALA KRISHNA J. 110533119012

CHHOTUBHAI GOPALBHAI PATEL INSTITUTE OF TECHNOLOGY

BARDOLI - 394350

DDEECCLLAARRAATTIIOONN

We hereby declare that the PSAR Reports, submitted along with the Project Report for the project

entitled “AN EXPERIMENTAL AND THEORETICAL ANALYSIS OF HEAT PIPES”

submitted in partial fulfilment for the degree of Bachelor of Engineering in MECHANICAL

ENGINEERING to Gujarat Technological University, Ahmedabad, is a bonafide record of the

project work carried out at C. G. PATEL INSTITUTE OF TECHNOLOGY, BARDOLI under the

supervision of Mr. Hiren Shah and that no part of any of these PSAR reports has been directly

copied from any students’ reports or taken from any other source, without providing due reference.

Name of The Students Sign of Students

1. DALAL RUSHABH M.

2. PATEL KAUSHAL S.

3. KABRAWALA KRISHNA J.

CHHOTUBHAI GOPALBHAI PATEL INSTITUTE OF TECHNOLOGY

BARDOLI - 394350

CCEERRTTIIFFIICCAATTEE

This is to certify that the PSAR reports, submitted along with the project entitled “AN

EXPERIMENTAL AND THEORETICAL ANALYSIS OF HEAT PIPES” has been carried out

by following students under my guidance in partial fulfilment for the degree of: Bachelor of

Engineering in MECHANICAL ENGINEERING 7th Semester of Gujarat Technological

University, Ahmadabad during the academic year 2013-14. These students have successfully

completed PSAR activity under my guidance.

Sr.

No. NAME

ENROLLMENT

NO. BATCH

1 DALAL RUSHABH M. 100530119034 B.E.

MECH.

VIIth

2 PATEL KAUSHAL S. 110533119011

3 KABRAWALA KRISHNA J. 110533119012

Mr. Hiren Shah Dr. Chinmay Desai

Internal Guide Head of the Department

Date : 13-Oct-2013

Patent Search & Analysis Report (PSAR)

Part-1 : Patent Search Technique Used

Part-2 : Basic data of Patent and Bibliographic

Team Id : 130009653

Name : Dalal Rushabh Manojkumar -

Patent Search Database Used : Other

If Selected Other, Then Specify the

Database:

www.freepatentsonline.com

Keywords used for search : heat,pipe,fins,

Search String : http://www.freepatentsonline.com/result.html?s

ort=relevance&srch=top&query_txt=heat+pipe

+fins&submit=&patents=on

Number of Results/Hits getting : 67561

Category / Field of Invention : Mechanical Engineering

Invention is related to/Class of

Invention :

Heat pipe

Title of Invention : Heat pipe with fins

Patent No :

Application No : 99306848.5

Date of Filing/Application : 1999-08-27

Priority Date : 1999-01-01

Publication /Journal Number - (Issue

No. of Journal in which patent is

published) :

EP1026469

Publication Date : 2000-08-09

First Filled Country : Europe

Also Published in:

Relevant Patent / Application No : 5279692

Applicant for Patent is : Individual

Inventor Details

Applicant Details

Sr

No

Name Address City Country

1 . Millas George S. Houston, Texas Texas US

Sr

No


1 . HUDSON

PRODUCTS

CORP

Houston, Texas Texas US

Part-3 : Technical part of patented invention

The present invention relates generally to the field of heat exchange in industrial processes and in particular

to a new and useful heat pipe structure.

Heat pipes are known in the field of heat exchange. Heat pipes are conventionally cylindrical, with circular

cross-sections. Caps are provided at each end to form a closed vessel. A wick is provided through the center

of the pipe. A working fluid is provided inside the heat pipe vessel

One end of the pipe is an evaporator end and is exposed to a warm substance, such as hot air. The other end is

a condenser end and is exposed to a cooler substance. The heat at the evaporator end causes the working fluid

to evaporate and travel to the opposite end of the heat pipe, to the condenser end. At the condenser end, the

working fluid gives up the heat to the heat pipe material, exchanging heat with the cooler substance, and

condenses to a fluid, which is then wicked back to the evaporator end to repeat the cycle. When the working

fluid is selected properly, heat can be efficiently transferred in this manner between substances having a

relatively small temperature difference, as well as those with larger temperature differences.

Non-circular tubes are known for use in heat exchangers. Heat exchanger tubes are distinct from heat pipes,

however, as they lack the internal structure of a heat pipe and cannot be used as a self-contained heat

exchange system. In particular, past designs are not well adapted to including a wick, which is an essential

element of a heat pipe, and required for it to function.

According to the invention there is provided a heat pipe having improved heat transfer efficiency,

comprising: a vessel body having a non-circular cross-section; a pair of end caps provided one at each end of

the vessel body sealing the ends thereof; wick means inside the vessel body for conveying a condensed

working fluid from one end of the vessel body to the other end; filling means through one of the end caps for

inserting the working fluid into the vessel body.

A heat pipe may be provided having an elliptical cross-section.

Heat exchange fins can be mounted to the heat pipe at the condenser end. The fins can be galvanized on the

heat pipe. Spacer pins can be used to support and space the heat exchange fins from each other. Internal

spacers can be provided within the heat pipe to add support to the heat pipe structure for longer heat pipes.

The various features of novelty which characterize the invention are pointed out with particularity in the

claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its

operating advantages and specific objects attained by its uses, reference is made to the accompanying

drawing in which a preferred embodiment of the invention is diagrammatically illustrated and in which :- Fig.

1 is a cross-sectional end elevation view of a heat pipe of the invention: and Fig. 2 is a right side, end

perspective view of a heat pipe of the invention.

Referring now to the drawing, in which like reference numerals are used to refer to the same or similar

elements, Fig. 1 shows the elliptical cross-section of heat pipe 10. The heat pipe 10 has a vessel body 30

which is non-circular in cross-section. An internal support 25 may be placed within the vessel body 30 to

Limitation of Prior Technology/Art :

Specific Problem Solved / Objective of Inventor :

Brief about Invention :

lend support to the vessel body 30, such as when the heat pipe 10 is elongate. The support 25 may be a planar

segment extending between two of the inside walls of the vessel body 30.

The interior of the heat pipe 10 also includes a wick 20 around the interior wall of the vessel body 30 which

conveys a working fluid (not shown) between the condenser and evaporator ends of the heat pipe.

The working fluid is heated and evaporates at the evaporator end and flows through the center of the vessel

body 30 to the condenser end, where the cooler substance outside the heat pipe 10 causes the working fluid to

condense. The working fluid is absorbed by the wick 20 and moves back toward the evaporator end by

wicking action.

The elliptical cross-section of the vessel body 30 provides a larger heat exchange surface area for the heat

pipe 10. Further, the working fluid is concentrated and minimized in the evaporator end of the heat pipe 10.

These improvements increase the efficiency of the heat pipe 10 in transferring heat between the substances at

each end.

A heat pipe (10) has an elliptical cross-section. Heat exchange fins (60) are mounted to the heat pipe (10) at

the condenser end (50). The fins (60) are galvanized on the heat pipe (10). Spacer pins (65) can be used to

support and space the heat exchange fins (60) from each other. Internal spacers can be provided within the

heat pipe (10) to add support to the heat pipe structure for longer heat pipes.

Fig. 2 displays the entire heat pipe 10, with evaporator end cap 40, condenser end cap 50 and heat exchange

fins 60. The heat exchange fins 60 may have fin spacers 65 adjacent each corner to support and space the heat

exchange fins 60 apart from each other. The heat exchange fins 60 are preferably made of carbon steel, so

that they may be bonded to the surface of the heat pipe vessel body 30 by galvanizing. Thus, the vessel body

30 is also preferably made of steel, such as carbon steel. The heat exchange fins 60 improve the heat

exchange properties of the heat pipe 10 by extending, or increasing, the heat exchange surface area.

A vent or valve 45 is located on the evaporator end cap 40. The valve 45 is used to fill the heat pipe with a

working fluid. Although it is shown on the evaporator end cap 40, the valve 45 may be positioned at either

end cap 40, 50.

The end caps 40, 50 are preferably made of carbon steel and welded to the vessel body 30 to form an air-tight

seal.

No

Key Learning Points :

Summary of Invention :

Number of Claims : 12

Patent Status : Granted Patent

How much this invention is related

with your IDP/UDP?

< 70%

Do you have any idea to do anything around the said invention to

improve it? :

Date : 13-Oct-2013




Team Id : 130009653




Database:


Keywords used for search : heat,pipe,cooling system,


ort=relevance&srch=top&query_txt=Heat+pipe

+system+cooling&submit=&patents=on




Invention :

Heat Pipe

Title of Invention : Heat pipe system for cooling flywheel energy

storage system

Patent No :

Application No : 10/702968





published) :

20040188059


First Filled Country : US

Also Published in:

Inventor Details

Applicant Details

Sr

No


1 . John Jr., Todd J. Elizabethtown, PA, US PA US

1 . Lindemuth, James

E.

Lancaster, PA, US PA US

1 . Mast, Brian E. Lancaster, PA, US PA US

1 . Gernert, Nelson J. Elizabethtown, PA, US PA US

1 . James Jr., Smith

L.

Lititz, PA, US PA US

Sr

No


1 . DUANE

MORRIS LLP

P. O. BOX 1003,

HARRISBURG, PA,

17108-1003

PA US


Flywheel systems are used for energy storage in backup power supplies (e.g., for telecommunication systems,

server farms, etc.). Energy is stored in the angular momentum of the flywheel. The flywheel systems are

typically stored inside silo canisters, and these canisters can be located above or below ground. Typical prior-

art flywheel systems dissipated a sufficiently small amount of waste heat that the canister could be cooled by

passive conduction from the canister to the exterior.

Newer flywheel systems dissipate too much power in the form of heat to cool the flywheels by conduction

alone.

The present invention is a system 100 for cooling a canister 130. In the exemplary embodiment, the canister

130 is the silo of a flywheel energy storage system 200 that is partially buried or completely buried about 60

to 240 centimeters below the surface 160 of the ground. Canister 130 is a vacuum housing. Canister 130 has

an energy storage flywheel having a motor housing 140 mounted inside the canister. It is contemplated that

system 100 may be used for cooling other types of canisters that have internal heat sources. It is also

contemplated that system 100 may be used for cooling canisters that are located above the surface 160 of the

ground.

The system 100 includes a first heat pipe 10, a second heat pipe 20 and a third heat pipe 30. The first heat

pipe 10 has an evaporator 12 and a condenser 14. The first heat pipe 10 is mounted with its evaporator 12

inside the canister 200 and its condenser 14 outside the canister. The first heat pipe 10 is mounted to the

motor housing 140 within the canister 130. In the exemplary system 100, the first heat pipe 10 is positioned

entirely below the ground surface 160, but it is contemplated that the first heat pipe 10 could be positioned

partially above the ground surface 160, or entirely above the ground surface.

The second heat pipe 20 has an evaporator 22 conductively coupled to the condenser 14 of the first heat pipe

10. The second heat pipe 20 has a condenser 24. The exemplary second heat pipe 20 is a thermosyphon. A

thermosyphon is a heat pipe that uses gravity to return fluid from the condenser 24 to the evaporator 22

thereof. The exemplary second heat pipe 20 is partially buried below the ground surface 160, and partly

above the ground surface. It is contemplated that the second heat pipe 20 could be positioned entirely below

the ground surface 160, or entirely above the ground surface.

The third heat pipe 30 has an evaporator 32 conductively coupled to the condenser 24 of the second heat pipe

20. The third heat pipe 30 has a condenser 34 with a plurality of fins 36 thereon. The exemplary fins 36 are

thirty-four circular aluminum plate fins arranged in a fin stack 38. Fins having other shapes and/or number of

fins are contemplated. The exemplary third heat pipe 30 is completely above the ground surface 160, but it is

contemplated that the evaporator 32 of heat pipe 30 could be located at or below ground level. The

evaporator 32 of the exemplary third heat pipe 30 is oriented substantially vertically, and the condenser 34 of

the third heat pipe is at a substantial angle (90-α) away from vertical. The angle α of the

condenser 34 of the third heat pipe 30 is at least about 5 degrees from horizontal. As an alternative to fins 36,

an extruded heat sink (not shown) may be mounted on the condenser 34 of the third heat pipe 30.

In the exemplary embodiment, all three of the heat pipes 10, 20 and 30 have wicks formed of sintered metal,




such as copper, for example. In heat pipe 10, the wick 13 only is present in the evaporator section 12. The

wick does not extend beyond the evaporator 12 into the condenser 14. FIG. 1 only shows the wick 13 of heat

pipe 10, but the wicks of heat pipes 20 and 30 may be configured similarly. The wick 13 may have a cross

section in the shape of an I-beam, or other wick shapes may be used. Because heat pipe 10 is vertical, heat

pipe 20 rises continuously without any local maximum, and the condenser 34 of heat pipe 30 is at least 5

degrees from the horizontal, gravity returns the condensed fluid to the evaporators 12, 22, 32 without the

need for wicks in the condensers 14, 24, 34.

In the exemplary embodiment, all three of the heat pipes use methanol as the working fluid. Other known

working fluids may be used.

As shown in FIG. 2, the first heat pipe 10 is mounted within a block 150 of metal having a hole therethrough

to receive the heat pipe. The block 150 is mounted to the flywheel system 140. For example, the block 150

may have a cylindrical bore 151 sized to receive the heat pipe 10. The block 150 can be cut in half, along a

plane passing through the center of the bore 151, to easily mount the heat pipe 10 within the bore. A

conventional thermal interface material (e.g., thermal grease, or thermally conductive adhesive) may be

placed on the inner surface of the bore 151 to ensure good conduction between block 150 and heat pipe 10

throughout the surface of the bore 151. The two halves of the block 150 may be fastened together by

conventional fastening means.

FIG. 2 shows a seal 40 where the first heat pipe 10 passes through the dome 120 of canister 130. In the

exemplary embodiment, the seal is a ?CONFLAT®? style flange, such as those manufactured by Varian, Inc.

of Palo Alto, Calif. This type of flange provides a reliable, all-metal, leak-free seal over a wide range of

temperatures. Alternatively, similar flanges made by other manufacturers, or other types of seals known to

those of ordinary skill may be used.

System 100 includes two thermocoupling devices 50 and 60. FIGS. 3 and 4 show the couplings 50, 60 in

detail. In the exemplary embodiment, each coupling 50, 60 comprises a metal block (e.g., copper or

aluminum) having a pair of cylindrical bores therethrough. The first bore of thermocoupling 50 receives the

condenser 14 of heat pipe 10, and the second bore of thermocoupling 50 receives the evaporator 22 of heat

pipe 20. The block 50 is split into two pieces 50a, 50b, with one of the bores split in half across the two

pieces. A thermal interface material (e.g., solder, thermal grease or thermally conductive adhesive is applied

to provide good conduction between the heat pipe 10 and the thermocoupling 50. In the exemplary

embodiment, the second heat pipe 20 is soldered into thermocoupling 50. Clamping fasteners (e.g., screws)

52 hold the two portions 50a, 50b of coupling 50 together. Alternatively, the block 50 may be split along a

plane of symmetry into two halves, so that each bore is divided in half.

Similarly, the first bore of thermocoupling 60 receives the condenser 24 of heat pipe 20, and the second bore

of thermocoupling 60 receives the evaporator 32 of heat pipe 30. The block 60 is split in two portions, with

one (or each) bore divided in half. A thermal interface material (e.g., thermal grease or thermally conductive

adhesive is applied to provide good conduction between the heat pipe 20 and the thermocoupling 60. Heat

pipe 30 is soldered to the bore of thermocoupling 60. Clamping fasteners 62 hold the two portions of

coupling 60 together. The coupling 60 may be split as shown in FIGS. 3 and 4, or split along the axis of

symmetry through both bores.

Although the exemplary thermocouplings 50, 60 are cylindrical, thermocouplings 50 and 60 may have other

shapes, such as a parallelepiped (block) shape.

[Thermocouplings 50, 60 have a sufficient length to achieve a desired temperature difference (ΔT). For

example, experiments have indicated that a ΔT of about 3.25 degrees centigrade is achieved between

the condenser of heat pipe 10 and the evaporator of heat pipe 20 using a thermocoupling 50 about 10

centimeters long. Thus, the ΔT from the two thermocouplings 50, 60 combined accounted for about

50% of the total ΔT between the motor housing 140 and the ambient. Other thermocoupling lengths are

contemplated, ranging from about 5 centimeters to about 20 centimeters.

In the exemplary embodiment, the second heat pipe 20 passes through a cabinet 70, which may be a flywheel

electronics module (FEM) cabinet. The cabinet 70 can provide support for the second heat pipe 20, if heat

pipe 20 extends a long distance above the ground. Alternative support structures for heat pipe 20 are also

contemplated.

The heat pipe system 100 operates passively, eliminating maintenance and reliability concerns. This makes

the exemplary system 100 advantageous for use in areas that are remote from maintenance workers.

Although the exemplary heat pipe system has three heat pipes a similar design may include only a single heat

pipe. The evaporator of the single heat pipe would penetrate the canister below ground and a condenser with

a fin stack or extrusion would be positioned above ground.

It is also contemplated that systems may be constructed with any number of two or more heat pipes. For

example, there may be a single thermocoupling, which may be positioned above or below ground.

Alternatively, additional heat pipes and thermocouplings may be interposed between the first and second (or

second and third) heat pipes. For example, an additional thermocoupling and fourth heat pipe may be used to

thermally couple the second and third heat pipes. Thus, configurations including four, five or more heat pipes

are also contemplated.

Although the exemplary embodiment includes a finstack, further variations of the exemplary embodiment are

contemplated. These may include, for example, use of heat pipes to bring the heat inside the flywheel to the

exterior of the canister, to be dissipated by interfacing to one or more heat dissipating means. The heat

dissipating means may include heat sinks such as the ambient air, a pumped water loop, the surrounding

ground, a phase change energy storage material, or the like.

For example, the various heat sinks could be ambient air, the ground 160 (if the canister 200 is buried) or

some other cooling medium such as pumped water-cooling or energy storage medium for example. Either

way, the heat pipe(s) are the conduit to transfer the heat to the heat sink. After the heat is transferred to the

exterior to the canister 200, the selection of the appropriate cooling method is dependent upon many

parameters such as geographical location, surrounding temperatures, availability of water, and whether the

canister 200 is above or below ground. When below ground, one exterior cooling approach uses heat pipes in

a spider like array leading away from the canister 200 which dissipates the heat to surrounding soil/aggregate.

Separate heat storage mediums can be substituted without changing the cooling system. These heat storage

mediums can be below ground or above ground. When the heat is brought to the surface for dissipation, one

or more heat pipes can be used as described above.

FIG. 5 shows a second exemplary system 500. The system has two heat pipes 10 and 30. Heat pipe 10 has its

evaporator inside the canister 200, and its condenser outside of the cabinet. Heat pipe 30 has a condenser with

a heat dissipation means, such as a fin stack. There is a single thermocoupling 60 connecting heat pipes 10

and 30. Thermocoupling 60 may be below or above ground. Other items in system 500 are the same as

system 100, and a description thereof is not repeated.

FIG. 6 shows a third exemplary system 600. The system has one heat pipe 10. Heat pipe 10 has its evaporator

inside the canister 200, and its condenser outside of the cabinet. Heat pipe 10 has a condenser with a heat

dissipation means, such as a fin stack. Other items in system 600 are the same as system 100, and a

description thereof is not repeated.

FIG. 7 shows a fourth exemplary system 700. In system 700, one or more heat pipes 730 transfer heat from

the flywheel 740 to a wall 710 of the canister. The canister wall 710 spreads the heat and conducts heat to the

surroundings (which may be ground, air, or both). Preferably, the heat pipe 730 abuts the inside wall 710 of

the canister, as shown in FIG. 7. Alternatively, the heat pipe 730 may penetrate the wall 710 or dome 720 of

the canister and abut the outside of the wall or dome (not shown). To increase the heat transfer capacity,

additional heat pipes 730 may be added to maintain a desired flywheel temperature. Alternatively, the

dimension of the heat pipes 730 may be increased to provide more heat transfer. Because heat pipes 730 are

relatively short, it is not necessary to use thermosyphon return of fluid to the evaporator. Thus, heat pipes 730

may be of any configuration, and may include wicks to transport liquid from the condenser to the evaporator.

One or more heat sinks 736 may be mounted to the exterior of canister wall 710 to enhance dissipation of

heat from the canister 710. The heat sink 736 may be of any design, including folded fins or any other

extended heat transfer surface.

Although the invention has been described in terms of exemplary embodiments, it is not limited thereto.

Rather, the appended claim should be construed broadly, to include other variants and embodiments of the

invention, which may be made by those skilled in the art without departing from the scope and range of

equivalents of the invention.

A system for cooling a canister has first, second and third heat pipes. The first heat pipe has an evaporator

and a condenser. The first heat pipe is mounted with its evaporator inside the canister and its condenser

outside the canister. The second heat pipe has an evaporator conductively coupled to the condenser of the

first heat pipe. The second heat pipe has a condenser. The third heat pipe has an evaporator conductively

coupled to the condenser of the second heat pipe. The third heat pipe has a condenser with a plurality of fins

on the condenser of the third heat pipe.

The present invention is a cooling system 100 that brings heat from inside a flywheel 140 to the exterior

where it is dissipated by one or more means. The cooling system 100 comprises one or more heat pipes that

transfer the heat to the exterior of the flywheel and those heat pipes dissipated the heat to various heat sinks.

Another aspect of the invention is a system comprising: a first heat pipe having an evaporator and a

condenser. The first heat pipe is mounted with the evaporator inside the canister and the condenser outside

the canister. A second heat pipe has an evaporator thermally coupled to the condenser of the first heat pipe.

The second heat pipe has a condenser. Means are provided for dissipating heat from the condenser of the

second heat pipe.

Another aspect of the invention is a system comprising: a flywheel stored within a canister; and a heat pipe

having an evaporator and a condenser. The heat pipe is mounted with the evaporator inside the canister and

the condenser abutting a wall of the canister.

According to another aspect of the invention, a system is provided for cooling a canister, the system

comprising first, second and third heat pipes. The first heat pipe has an evaporator and a condenser. The first

heat pipe is mounted with its evaporator inside the canister and its condenser outside the canister. The second

heat pipe has an evaporator thermally coupled to the condenser of the first heat pipe. The second heat pipe

has a condenser. The third heat pipe has an evaporator thermally coupled to the condenser of the second heat

pipe. The third heat pipe has a condenser with a heat dissipation mechanism thereon.

No






with your IDP/UDP?

< 70%


improve it? :

Date : 13-Oct-2013




Team Id : 130009653




Database:


Keywords used for search : heat,pipe,vaporisation,



+vaporisation&submit=&patents=on




Invention :

Heat Pipe

Title of Invention : Heat pipe for vaporisation

Patent No :






published) :

6880624



Also Published in:


Inventor Details

Applicant Details

Sr

No


1 . Pinneo, John

Michael

Portola Valley, CA California US

Sr

No


1 . P1 Diamond, Inc. Santa Clara, CA California US


Heat pipes are well-known devices that effect the transport of heat from a source through ordinary solid

components. Heat pipes commonly consist of a closed plenum, or space, said space being partially filed with

a substance or heat exchange medium (a working fluid) which is a liquid at the temperature of the cooler end

(heat sink region) of the heat pipe and which is a gas at the temperature of the warmer end (heat source

region) of the heat pipe.

The plenum is often also partially occupied by a fibrous material that serves as a capillary mass that effects

transport of liquid heat exchange medium from the heat sink region to the heat source region, at which the

liquid heat exchange medium vaporizes, absorbing heat from the heat source, and is then transported by

means of its own pressure to the heat sink region, at which it recondenses to a liquid, yielding up its heat of

vaporization and effecting transport of heat energy from the heat source to the heat sink. Capillary action then

transports the condensed heat exchange medium back to the heat source to renew the cycle.

Because of the relatively large amount of heat that is required to drive the continuous vaporization and

condensation cycle, heat pipes can exhibit an effective thermal conductivity of over 100 times that of any

known bulk material. By suitable choice of structural materials, heat exchange fluids, and capillary materials,

heat pipes have been made to operate at temperatures ranging from cryogenic to 2000 degrees Centigrade.

Their excellent thermal transport properties and mechanical simplicity have led to their widespread adoption

in thermal management systems that require efficient transport of heat from sources to sinks.

A specific example of heat pipe utility is their employment in laptop and similarly thermally constrained

computer systems. Microprocessors and their ancillary integrated circuits generate heat during operation. In

general, the faster such devices operate, the more heat they generate. In computers that require high

packaging densities to achieve small size, such as laptop personal computers, it is very difficult to provide for

adequate heat rejection to maintain safe and reliable operation of microprocessors and other integrated

circuits. Heat pipes have made a great contribution to solving this problem.

Those of ordinary skill in the art will realize that the following description of the present invention is

illustrative only and not in any way limiting. Other embodiments of the invention will readily suggest

themselves to such skilled persons.

Diamond exhibits the highest known bulk material thermal conductivity. Both natural and synthetic diamond

have been measured at greater than 20 W/cm/° C. thermal conductivity. For comparison, the best metals,

being silver, gold, and copper, all measure approximately 4 W/cm/° C. on this scale. Furthermore, the

exceptional thermal conductivity of diamond is substantially isotropic, that is, there is no significant

directional variation in thermal conductivity.

Diamond also exhibits the highest known thermal diffusivity, or speed of heat conduction, of any known

material. This means that fast transient heat pulses can be absorbed and propagated away from their source by

diamond more rapidly than with any other known material.

Diamond has a low thermal expansion coefficient, ranging between 1 to 2 parts per million per degree




Centigrade over normal electronic operating temperatures. This provides a good thermal expansion match to

important electronic materials such as silicon and gallium arsenide. It also confers on diamond a high degree

of resistance to breakage induced by thermal gradients or thermal shock.

Diamond is inert to chemical attack by any known reagent at temperatures below approximately 400 degrees

Centigrade. This renders diamond compatible with a wide range of heat pipe working fluids and with

corrosive environments.

Diamond is the hardest and stiffest known material, giving it great structural integrity when subjected to

forces either exogenously applied or generated by differential thermal expansion forces at interfaces between

diamond bonded to other materials.

Diamond is an excellent electrical insulator, providing electrical isolation in particular applications that

require that property. It can be rendered electrically conductive if needed by modifications to its synthesis

process (doping with boron) or coating with thin metal layers using processes familiar to those skilled in the

art.

Finally, diamond is non-toxic and is biocompatible, in contrast to beryllium oxide, a ceramic having good

thermal thermal conductivity that is sometimes used as a heat transfer material. If improperly fabricated or

disposed of, beryllium oxide can induce berylliosis, an untreatable fatal disease.

The use of diamond in the present invention as a heat pipe wall material brings numerous benefits. First, heat

flow from the source across the heat pipe wall to and from the internal working fluid is greatly improved,

leading to enhanced heat transfer efficiency in operation of the heat pipe. Specifically, use of diamond (at a

thermal conductivity of 20 W/cm/° C.) as a wall material rather than copper (at a thermal conductivity of 4

W/cm/° C.) in an otherwise identical configuration will provide up to (20/4) times, or 500%, better thermal

conductance across the wall.

In addition, because of the superior mechanical properties of diamond, thinner walls may be used compared

with lesser materials, increasing wall thermal conductance still further. For example, use of a diamond wall

with thickness half that of the otherwise dimensionally idential copper wall will increase wall thermal

conductance by two, or 200%. Note that this increase is multiplicative with the increase due to dimond''s bulk

thermal conductivity as compared with copper. Thus, the increase of 500% noted in the first benefit

description above would increase to 1,000% if combined with one-half reduced wall thickness made possible

by using diamond.

Use of diamond as the wall material can increase the amount of heat energy transported by the heat pipe.

Because heat transfer across the wall is often so poor as to constitute the rate-limiting step in the overall

operation of the heat pipe, the inherent capacity of the heat pipe''s working fluid heat transport system is

underutilized. Improved wall heat transfer couples additional heat into the working fluid, resulting in greater

heat transport in underutilized heat pipes.

Use of diamond as a wall material not only can increase heat transport across the wall section, as described

above, but can provide a lateral heat spreading function which can be very beneficial when removing heat

from sources that exhibit strong thermal gradients. For example, microprocessors exhibit ?hot spots? (regions

on the chip that run hotter than others). Often, it is the temperature of these hot spots that limits processor

clock rate. If such a chip is closely coupled to a flat diamond element, such as may be used as a heat pipe

wall, the high lateral thermal conductivity of diamond will reduce hot spot temperatures, allowing the device

to be operated at higher clock rates. Note that this benefit derives from diamond''s high isotropic thermal

conductivity. Other materials, such as single-crystal graphite, are known to exhibit high thermal conductivity

in one plane, but not others. These materials can only provide good heat transfer in one direction, and cannot

simultaneously provide good longitudinal and lateral heat transport.

Use of diamond as a wall material at both ends of the heat pipe additionally increases heat transport by

enhancing removal of heat from the heat pipe condensation end to the next element in the heat transport

system. This is often the surrounding ambient air.

Referring now to FIGS. 2A through 2F in order, in one embodiment according to the present invention, a heat

pipe is fabricated from a diamond tube. In the exemplary embodiment disclosed herein the dimensions given

in order to understand the present invention are exemplary only and are not meant as limiting. Persons of

ordinary skill in the art will appreciate that these dimensions are not critical and, in any event, may be scaled.

In a presently contemplated embodiment within the scope of FIG. 2, the diamond tube may have an outer

diameter of 10 mm, an inner diameter of 9 mm, and a wall section thickness of 0.5 mm. The length of the

tube may be 100 mm.

As may be seen from an examination of FIG. 2A, the tube is made by performing chemical vapor deposition

of diamond on a mandrel 10, formed from a material such as molybdenum having an outer diameter of 9 mm

and length 60 mm. The mandrel 10 has been prepared for diamond deposition by inducing nucleation through

pre-deposition abrasion with diamond dust by means long established in the art of diamond chemical vapor

deposition (CVD).

Referring now to FIG. 2B, the mandrel 10 is fixed within a diamond deposition system and is coated with

diamond material 12 to a nominal thickness of 1 mm along its entire length, according to diamond CVD art

well-known to the industry.

Referring now to FIG. 2C, following diamond deposition, the molybdenum mandrel 10 is removed using

mixed nitric and hydrochloric acids or other chemical etchant capable of attacking and dissolving

molybdenum. The diamond tube so formed is unaffected by the mandrel removal process. The ends of the

diamond tube are trimmed to a uniform profile if needed using a Nd:YAG laser cutting system of the type

commonly used to cut and process CVD diamond. FIG. 2C shows the structure of the diamond tube after

removal of the mandrel and trimming of the tube ends.

Subsequent to end trimming of the tube, each end is metallized with a sequence of layered metals to prepare

the ends of the tube for attachment of brazed or soldered end caps. A specific metallization sequence suitable

for use in the present invention begins with a layer of about 200 Angstroms titanium deposited directly on the

diamond. Next, 1000 Angstroms platinum is deposited over the titanium, followed by 10,000 Angstroms

gold. The tube ends are metallized to a length on the outer diameter of at least about 5 mm from each end.

FIG. 2D shows the structure of the diamond tube after deposition of the metallization layers 14 and 16 at the

tube ends.

First and second metal caps 18, and 20 consisting of tungsten machined to fit closely but without significant

interference over the diamond tube ends are procured and prepared for soldering or brazing. First cap 18 is

fitted over one tube end and is soldered or brazed in place to the metallization region 14, using solder or

braze formulations well known in the art.

A bundle 22 of clean, fine molybdenum wires of individual diameter not more than 0.01″ is prepared

such that the bundle has a length of not more than 100 mm and not less than 95 mm, with its aggregate cross-

section area occupying between 10% and 75% of the 9 mm inner diameter of the diamond tube. The wire

bundle 22 is inserted into the diamond tube to its full extent.

The diamond tube is then charged through its open end with heat exchange fluid, being in this instance

distilled water. The volume of the working fluid is not less than 1 cubic centimeter, and not more than 2 cubic

centimeters. The diamond tube is oriented vertically with its open end up. FIG. 2E shows the structure of the

diamond tube after attaching the first end cap 18, inserting wire bundle 22, and charging the tube through its

open end with heat exchange fluid.

Subsequently, the second end cap 20 is fixed to the open end and soldered or brazed in place to the

metallization region 16 as was the case with first end cap 18. This completes the fabrication of the heat pipe

as shown at FIG. 2F.

The heat pipe may then be connected to a test fixture consisting of an electrical heat source with a maximum

temperature of 125 degrees Centigrade and a copper heat sink cooled with circulating water having a

temperature of 20 degrees Centigrade, both heat source and heat sink being sized to deliver and remove,

respectively, up to 1kW of thermal power. One end of the diamond tube is secured to the heat source, while

the other end is secured to the cooled heat sink. In operation, heat transfer through the diamond heat pipe is

found occur at a level exceeding 240% of that of a tube of otherwise identical construction made from

copper.

According to a second embodiment of a heat pipe according to the present invention as shown in FIGS. 3A

and 3B, a rectangular heat pipe is constructed from copper or other suitable material such as aluminum, with

a working fluid consisting of water and with a compatible capillary fiber material as is well known in the art

of heat pipe construction. As with the previous embodiment of the present invention disclosed herein, the

dimensions given in order to understand the present invention are exemplary only and are not meant as

limiting. Persons of ordinary skill in the art will appreciate that these dimensions are not critical and, in any

event, may be scaled.

The heat pipe 30 has a length of 12″, comprising a center section 32 with two widened end regions 34

and 36 consisting of cross-section dimensions 2″ wide×0.5″ high, these widened end regions

34 and 36 extending toward each other for a length of 1 inch, after which the width of the heat pipe is

reduced over a distance of 2″ to a value of 0.5″, resulting in a cross-section of 0.5″

wide×0.5″ high throughout the 6″-long constant-section region 32 of the heat pipe.

The heat pipe 30 presents at least one planar surface 38 exhibiting dimensions of 1″×1″. A

square hole (not shown) is cut into this planar surface, the hole centered on the 1″×1″ surface

and having dimensions of 0.75″×0.75″. Following this operation, the heat pipe is checked for

adequate working fluid fill, which is replenished if needed, and the heat pipe is clamped such that the square

hole is oriented horizontal, facing up.

A diamond wall element 40 is prepared consisting of a solid slab of diamond having dimensions

0.9″×0.9″×0.3 mm. One major face of this diamond wall element 40 is metallized as

described earlier to accept solder or braze attachment. The diamond wall element 40 is centered on the hole

with the metallized face in opposition to the heat pipe 30 and is soldered or brazed around its entire periphery

to the heat pipe 30. This completes the integration of the diamond wall element into the heat pipe.

The heat pipe 30 with diamond wall element 40 is integrated intn atest apparatus which comprises suitable

mechanical supports, an electrical heat source having a planar element of major dimensions

0.5″×0.5″, the surface being adequately flat to provide intimate physical and thermal contact

when brought into juxtaposition with the diamond heat pipe wall element. The other end of the heat pipe is

fixed to a cooled heat sink of temperature 20 degrees Centigrade adequate to absorb heat energy transported

through the heat pipe. Power is applied to the heater in contact with the diamond wall element such that the

heater assumes a temperature of approximately 125 degrees Centigrade. Thermal power transport through the

heat pipe is found to exceed 175% of that observed with an otherwise identical heat pipe using a 75%

tungsten, 25% copper heat spreader alloy as the wall element into which the heater power is coupled.

The present invention contemplates the use of multiple diamond heat pipe wall elements 40 at multiple

positions in an extended heat pipe like that of FIGS. 3A and 3B, providing heat removal from multiple heat

sources with a single heat pipe.

The present invention further contemplates use of diamond heat pipe wall elements 40 at hot and cold zones

of the heat pipe 30, thereby to improve heat transport across the wall at both sites.

The present invention further contemplates use of diamond wall elements 40 in heat pipes 30 that are

employed to promote enhanced thermal uniformity in addition to, or in place of, transport of heat from a

source to a sink.

The present invention contemplates use of diamond wall elements 40 in heat pipes 30 without limitation as to

the particular shape, geometry, or topology of the heat pipe or diamond wall element that may be imposed by

engineering requirements. In this respect, persons of ordinary skill in the art will recognize that the

embodiments disclosed herein are merely illustrative and not limiting, especially as to design details such as

shape and geometry.

The present invention contemplates use of diamond wall elements 40 in heat pipes 30 without limitation as to

the operating temperature of either the heat source or the heat sink, provided those temperatures lie within the

operational limits of the diamond wall element 30 and the remaining components and materials used in heat

pipe 30.

The present invention contemplates use of diamond wall elements 40 in heat pipes 30 wherein the diamond

wall elements 40 function to transport heat out of the heat pipe.

Persons of ordinary skill in the art will recognize the above recitations as being offered as extensions, not

limitations, of the broad applicability of the present invention.

While embodiments and applications of this invention have been shown and described, it would be apparent

to those skilled in the art that many more modifications than mentioned above are possible without departing

from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the

appended claims.

A heat pipe has at least one diamond element through which at least a portion of heat flowing into the heat

pipe passes.



The present invention is a heat pipe employing diamond as the thermal transfer wall material through which

heat is transported into and/or out of the heat pipe. Several improvements that are of great utility result from

this invention which will be described below following a brief review of the properties of diamond that

particularly suit it for this invention.

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Keywords used for search : heat,pipe,amplifier,



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Invention :

Heat Pipe

Title of Invention : Heat pipe amplifier

Patent No :






published) :

4106554



Also Published in:


Inventor Details

Applicant Details

Sr

No


1 . Arcella Frank G. Bethel Park, PA Pennsylvania US

Sr

No


1 . Westinghouse

Electric Corp.

Pittsburgh, PA Pennsylvania US

1 . Westinghouse

Electric Corp.

Pittsburgh, PA Pennsylvania US


The combination of two conventional heat pipe structures in an end-to-end opposing relationship, with one

end of the combination being exposed and responsive to the temperature of monitored environment or object,

while the heat input to the opposite end is controlled, is disclosed in detail in pending U.S. Patent application

Ser. No. 713,175, now U.S. Pat. No. 4,067,236, entitled "Novel Heat Pipe Combination", filed Aug. 10,

1976, assigned to the assignee of the present invention and incorporated herein by reference. In the structure

disclosed in this referenced application, adjacent condenser sections of the respective heat pipe sections

combine to form a common condenser region which is in turn coupled to an appropriate heat sink.

The temperature of the monitored end and the temperature of the controlled end of the heat pipe combination

each produce a vaporization of the working fluid in the wick portion of the respective heat pipe sections,

which results in a flow of the respective vaporized fluids in opposing directions which ultimately meet to

form an interaction interface within the common condenser region. The position of the interaction interface is

a function of the vapor pressures in the respective heat pipe sections, which in turn is a function of the

temperatures and the heat source strengths at the monitored and controlled ends of the heat pipe combination.

The same working fluid is employed in the respective heat pipe sections of the heat pipe combination.

The heat, or temperature, at the monitored end can be controlled or measured by controllably introducing heat

to the evaporator section corresponding to the controlled end of the heat pipe combination.

Referring to FIG. 1 there is a sectioned illustration of a heat pipe combination HC in accordance with the

teachings of the above-identified pending application wherein heat pipe section HP1 and a heat pipe section

HP2 are combined to form the integral heat pipe combination HC having a common vapor cavity and a

communicating wick structure. The construction of the respective heat pipe sections HP1 and HP2 is in

accordance with conventional heat pipe technology wherein the portion of the heat pipe HP1 adjacent to the

heat source HS1 is defined as the evaporator section E1, whereas the section of the heat pipe HP1

downstream from the evaporator section E1 and adjacent to the heat sink section S1 is defined as the

condenser section C1. Similarly, the heat pipe HP2, which is connected in an end-to-end opposing

relationship with the heat pipe HP1 to form the heat pipe combination HC consists of an evaporator section

E2 adjacent to heat source HS2 and a condenser C2 corresponding to the portion of the heat pipe HP2

coupled to the heat sink section S2. Heat sink sections S1 and S2 are illustrated as consisting of radiator fins

F which combine to form heat sink S of the heat pipe combination HC. Heat sink sections S1 and S2 can be

radiative, convective or conductive. The heat pipes HP1 and HP2 are constructed in accordance with

conventional heat pipe principles such as that disclosed in U.S. Pat. No. 3,681,843, entitled, HEAT PIPE

WICK FABRICATION, issued Aug. 8, 1972, assigned to the assignee of the present invention, and

incorporated herein by reference.

The integral combination of the heat pipes HP1 and HP2 defines an evacuated chamber, or cavity, 12 whose

side walls are lined with a capillary, or wick 30, that is saturated with a volatile working fluid. The working

fluid selected is dictated in part by the anticipated operating temperature, i.e., ammonia (-50° C to +50° C),

methanol (0° C to 80° C), water (40° C to 150° C) and sodium (500° C to 800° C). The material selected for

constructing the housing H is selected to be compatible with the working fluid, or fluids, and includes

aluminum (ammonia), stainless steel (methanol and sodium) and copper (water and methanol).




The operation of the heat pipes HP1 and HP2 combines two familiar principles of physics; vapor heat transfer

and capillary action. Vapor heat transfer serves to transport the heat energy from the evaporator section E1

and E2 to the condenser sections C1 and C2 respectively which collectively form the common condenser

section. The vapor flow from the respective heat pipes contact to form a common interaction interface I. The

location of the interaction interface I within the common condenser section CS is a function of the relative

strengths of the heat sources HS1 and HS2. Capillary action returns the condensed working fluids of the

respective heat pipes HP1 and HP2 back to the respective evaporator sections, as indicated by the arrows in

FIG. 1, to complete the cycle.

The working fluids in the respective heat pipes absorb heat at the evaporator sections E1 and E2 and change

its liquid state to a gaseous state. The amount of heat necessary to cause this change of state is the latent heat

of vaporization. As the working fluid in the respective heat pipes vaporizes, the pressure in the evaporator

sections E1 and E2 increases. The vapor pressure sets up a pressure differential between the evaporator

sections and the condenser sections of the respective heat pipes HP1 and HP2, and this differential pressure

causes the vapor, and thus the heat energy, to move from the evaporator sections to the condenser sections of

the respective heat pipes. When the vapor arrives at the condenser sections C1 and C2, they are subjected to a

temperature slightly lower than that of the evaporator sections due to thermal coupling to the heat sinks S1

and S2, and condensing occurs thereby releasing the thermal energy stored in the heat of vaporization at the

respective condenser sections. As the vapor condenses the pressure at the condenser sections C1 and C2

decreases so that the necessary pressure differential for continued vapor heat flow is maintained.

Movement of the working fluids from the respective condenser sections to the evaporator sections is

accomplished by capillary action within the wick 30 which connects the condenser and evaporator sections of

the respective heat pipes. The interaction interface I corresponds to the interface established by the mixing or

contact of the opposed vapor flow patterns of the working fluids effected by the respective heat pipes HP1

and HP2. The location of the interaction interface I within the common condenser section of the heat pipe

combination HC is a function of the heat strengths Q1 and Q2 associated with the heat sources HS1 and HS2

respectively.

Assume, for the purposes of discussion, that the heat source HS1 corresponds to a monitored environment or

or object such as an electronic circuit package or a fluid flow medium which exhibits an unknown

temperature condition that serves as a heat input, or heat flux, to the evaporator section E1. The evaporator

section E1 of heat pipe HP1 corresponds to the monitored end of the heat pipe combination HC whereas the

evaporator section E2 of heat pipe HP2 corresponds to the controlled end of the heat pipe combination HC

inasmuch as its heat source HS2 is determined by the controlled heat input from a controllable heat source

HS.

In the typical embodiment of FIG. 1, which is described in detail in the above-referenced pending

application, a temperature signal from a temperature sensor TS associated with the monitored end ME of the

heat pipe combination HC serves as an input to the controllable heat source HS which in turn controls the

heat strength Q2 of the controlled end CE to effect movement of the interaction interface I to control the

amount of condenser section and corresponding heat sink section available to the monitored end ME to

control the heat flow from the monitored end ME and thereby control the temperature of the monitored end

ME.

The effectiveness and efficiency of the heat pipe combination can be substantially improved by employing

different working fluids in the respective heat pipes, each working fluid, WF1 and WF2, exhibiting different

vapor pressures. The use of compatible working fluids, i.e., water and methanol, exhibiting different vapor

pressures in the heat pipe combination HC supports an amplifier mode of operation such that the heat pipe

combination HC functions as a heat pipe heat amplifier. Inasmuch as the evaporator sections E1 and E2

operate with a common over-pressure, i.e., there is vapor communication between evaporator sections E1 and

E2, the temperatures of both evaporator sections relate through the vapor pressure curves of the respective

working fluids WF1 and WF2 associated with the heat pipe sections HP1 and HP2 respectively. As a result, a

small change in heat flux HS2 at evaporator section E2 will take up condenser area at section C2 causing the

temperature at evaporator section E1 to change due to a loss in its condenser area at C1. Since the

temperature at E2 is lower than the temperature at E1, a small change in temperature at evaporator section E2

is amplified in effect at E1, thus heat transfer effects at one end of the heat pipe combination HC are

amplified at the other end.

During operation of the heat pipe combination HC, the more volatile working fluid will collect at the end of

the condenser section CS farthest from the highest temperature heat source. Since the vapors of the working

fluids will coexist at a common heat pipe pressure, and since the vapor pressures of both working fluids can

only be equal at different fluid temperatures, each end, i.e., the controlled end CE and the monitored end ME,

of the heat pipe combination HC will operate at a different temperature. The more volatile working fluid

WF2, which in the case of the water-methanol working fluid combination is the methanol, has collected at the

end of the condenser section farthest from the heat source HS1 of the monitored end ME, can be heated as a

result of heat input from the controllable heat source HS2 associated with the controlled end CE. Less heat

flux is required at the controlled end CE which is associated with the more volatile working fluid WF2 to

effect changes in the heat flux, or heat flow from, or temperature of, the evaporator section E1 of the

monitored end ME because the more volatile working fluid WF2 has:

l. a greater vapor pressure than the working fluid WF1 at a common temperature, and

2. heat losses are less at the reduced temperatures of the condenser section C2 associated with the more

volatile working fluid WF2.

Thus, the employment of two compatible working fluids, each exhibiting different vapor pressures, in the

same heat pipe cavity of the heat pipe combination HC results in a heat pipe heat amplifier mode of

operation.

A graphical illustration of the vapor pressures of a few low temperature heat pipe working fluids is illustrated

in FIG. 2. Referring to FIG. 2, it is seen, for a 50:50 water-methanol working fluid combination in the heat

pipe combination HC, when the evaporator section associated with the water working fluid is at 80° C, the

evaporator section associated with the methanol working fluid will be at 48° C due to intercommunication of

vapor pressures.

In a heat pipe combination consisting of a common condenser section with evaporator sections at either end,

two working fluids of different vapor pressures are employed to effectively form two heat pipe sections

within the same cavity to support an amplifier mode of operation.

The efficiency of the heat pipe combination to control and monitor the heat, or temperature, of a monitored

environment or object in accordance with the heat pipe combination structure defined in the above-referenced

pending application can be significantly improved by utilizing two compatible working fluids of different

vapor pressures in the heat pipe combination to establish an amplifier mode of operation of the heat pipe



combination. The movement of the respective working fluids within the heat pipe combination is controlled

by the heat input, or heat flux, from the heat sources associated with the evaporator sections disposed at either

end of the common condenser section. One evaporator section is associated with the monitored environment

or object and thus the monitored environment or object corresponds to its heat source while the opposite

evaporator section is exposed to a controlled heat source.

During operation of the heat pipe combination, the more volatile working fluid will collect at the end of the

condenser section farthest from the highest temperature heat source. With this separation of working fluids,

two heat pipes will then be formed within the same working cavity. Since the vapors of the different working

fluids will coexist at a common heat pipe pressure, and since the vapor pressures of both fluids can only be

equal at different fluid temperatures, each end of the heat pipe combination will operate at a different

temperature. The more volatile fluid, which has collected at the end of the condenser section farthest from the

heat source to be controlled, can be heated via the controllable heat source. Less heat flux is required from

the controllable heat source associated with the more volatile working fluid to effect changes in the heat flux,

temperature, of the evaporator section associated with the monitored environment because the more volatile

fluid has a greater vapor pressure than the other working fluid at a common temperature, and heat losses are

less at the reduced temperatures of that portion of the condenser section occupied by the more volatile

working fluid.

Thus, small power levels can be employed and amplified by the two fluid heat pipe combinations to achieve

the same heat flow control of a single fluid heat pipe system requiring higher power levels.

The employment of two compatible working fluids with different vapor pressures in the same heat pipe

cavity of the heat pipe combination disclosed in the above-identified pending application results in a heat

pipe amplifier.

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Keywords used for search : heat,pipe,evaporation,



+evaporation&submit=&patents=on




Invention :

Heat Pipe

Title of Invention : heat pipe for evaporation

Patent No :






published) :

3568762



Also Published in:


Inventor Details

Applicant Details

Sr

No


1 . Willis E.

Harbaugh

Leola, PA Pennsylvania US

Sr

No


1 . RCA Corporation New York New York US


In prior art heat pipes, some loss in heat pipe efficiency resulted from the friction occurring between the

vaporized working medium which moves from the heat input zone to the heat output zone of the heat pipe

and the fluid working medium which moves along the walls of the heat pipe from the heat output zone to the

heat input zone. These opposing flows tend to retard each other along the capillary walls of the heat output

zone.

A heat pipe is a vapor device which is used to convey heat from a heat source to a heat output or dissipation

zone. Such a device is described in general terms in an article entitled "Structures of Very High Thermal

Conductance" by G. M. Grover in Volume 35 of the Journal of Applied Physics, pages 1990 and 1991. The

heat pipe usually comprises a closed tubular structure having a lining of capillary material and a vaporizable

heat transfer or working medium therein. The capillary lining can consist of wire cloth, porous matrix

materials or channeling in the walls of the heat pipe itself. The working medium is selected to have a

vaporization temperature equal to the desired operating temperature of the heat pipe. For example, lithium

may be used as a working medium for high temperature applications and water can be used for lower

operating temperatures. For most efficient operation all undesirable foreign gases are removed from the heat

pipe envelope and the working medium.

Before heat is applied, preferably substantially all of the working medium is present in liquid form in the

capillary walls of the heat pipe. Heat is applied from a heat source to the heat input zone of the heat pipe

causing the liquid working medium in the capillary walls of this zone to vaporize and fill the interior of the

heat pipe. The vaporized medium expands and then condenses on the inner walls of the heat output or heat

dissipation zone of the heat pipe, giving up its latent heat of vaporization. The condensed liquid working

medium is then transported by capillary action along the heat pipe wall from the heat output zone to the heat

input zone to fill the area vacated by the vaporized working medium. In this way heat is transferred from a

heat source to a heat output zone while the working medium is circulated through the heat pipe. Since the

heat pipe is a closed system and has no moving parts to wear out, it is useful for applications such as space

where maintenance is difficult. Heat pipes are also useful in enclosed spaces and in airless environments

where other cooling techniques are difficult to use.

FIG. 1 is a longitudinal sectional view of a preferred embodiment of the improved heat pipe;

FIG. 2 is a sectional view taken along the line 1-1 of FIG. 1; and

FIG. 3 is a longitudinal sectional view of a second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The outer envelope 10 of the heat pipe preferably is a tubular structure closed at both ends. It can be

constructed of any suitable good heat conducting material. Molybdenum is often used for high temperature

heat pipes and copper for those which operate at lower temperatures. A lining 12 of capillary material covers

the entire inside surface of the heat pipe. This lining can be wire mesh screening, a porous matrix material, or

even can be channeling in the walls of the heat pipe. The heat pipe is divided into two zones, a heat input




zone 14 and a heat output or dissipation zone 16.

A funnel-shaped vapor duct 18 is mounted to extend into the heat output zone 16 of the heat pipe. It is

preferably fabricated of the same metal as the outer envelope 10. The duct 18 consists of a pipelike structure

of a uniform diameter over most of its length which diameter is substantially less than the inner diameter of

the capillary lining 12. The end 20 of the duct 18 adjacent to the heat input zone 14 is flared outwardly so that

its outer edge is in contact with the capillary lining 12 along a line 22 at the approximate dividing line

between the heat input zone 14 and the heat output zone 16. The relatively narrower end 21 of the vapor duct

18 is located adjacent to the remote end 24 of the heat output zone of the heat pipe. This narrow end 21 of the

vapor duct 18 has a rim 25 which extends outwardly and curves downwardly to inhibit the vaporized working

medium from flowing down the sides of the vapor duct 18 and to direct it relatively close to the capillary

walls 12. The remote end of the heat pipe 24 in the heat output zone is formed by a reentrant arch of rotation

about a point 26 located adjacent to and coaxially with the center of the narrow end 21 of the vapor duct 18.

To retain the vapor duct 18 at a proper position in the heat pipe, the outer edge of its flared end 20 is attached

to the capillary lining 12 of the heat pipe along a line 22 by welding or other appropriate means. Further

mechanical stability is provided, if desired, by the addition of three rigid metal radial braces 27 extending

from the capillary lining 12 to the vapor duct 18 at points 28 adjacent to the narrow end 21 of the duct as

shown in FIG. 2. These braces 27 are usually fabricated of the same material as the body of the vapor duct 18

and may be made an integral part of the duct 18. The outer ends of the radial braces 27 are in contact with or

may be fastened to the capillary lining 12 of the heat pipe walls by welding or other suitable means.

The second embodiment of the invention shown in FIG. 3 has an adiabatic zone 34 between the heat input

zone 14 and the heat output zone 16. The temperature remains substantially constant in the adiabatic zone,

and the capillary lining 12 is in this zone need not be free to release vapor or absorb condensing liquid. In this

embodiment, the vapor duct 18 terminates in a sleeving 38 at its flared end 20. This sleeving 38 constitutes a

part of the vapor duct 18 and has a diameter large enough to fit tightly against the capillary lining 12 in the

adiabatic zone 34. The sleeving 38 is attached to the capillary walls 12 of the heat pipe by welding or other

suitable means. This will provide adequate mechanical support for the vapor duct 18 without further bracing.

Other features of this embodiment are identical to those described for the first preferred embodiment.

In either embodiment heat is applied to the heat input zone 14 causing the working medium contained in the

capillary walls 12 to vaporize and expand throughout the heat pipe. The vaporized working medium 40 is

forced to move through the vapor duct 19 since the flared end 20 of the vapor duct 18 completely blocks off

other portions of the interior of the heat pipe. The vapor 40 moves through duct 18 and passes out of the duct

at the narrow end 21. The curved rim 25 around the narrow end 21 of the vapor duct 18 and the reentrant arch

of rotation configuration of the end 24 of the heat pipe smoothly reverses the flow of the vaporized working

medium 40 so that most of the vapor flows close to the capillary walls 12 of the heat output zone 16 where it

condenses on the capillary walls 12. Both the vaporized working medium and the liquid in the capillary walls

flow in substantially the same direction in the heat output zone 16. Liquid working medium then moves

through the capillary walls from the heat output zone 16 to the heat input zone 14 to fill areas vacated by the

heated vaporized working medium 40.

The vapor duct 18 provides more efficient circulation of the working medium because the vaporized working

medium 40 moving toward the heat output zone 16 is separated from the capillary walls 12 of the heat output

zone 16 in which liquid working medium is moving in the opposite direction. Without the vapor duct 18

these opposing flows would tend to retard each other decreasing the heat transfer capability of the heat pipe.

Little of the efficiency of the capillary walls 12 is lost by attaching the vapor duct 18 to them. Liquid working

medium moves past line 22 where the vapor duct is attached to the capillary walls through the interior

portions of the capillary lining to react the heat input zone 14 of the heat pipe.

A heat pipe in which a vapor duct is mounted in the heat output zone to separate the vaporized working

medium from the capillary walls of the heat output zone while the vapor is moving in a direction opposite to

fluid capillary motion in the walls.

The foregoing problems of oppositely flowing gaseous and liquid media are overcome by an improved heat

pipe which includes a vapor duct mounted to extend into the heat output zone of the heat pipe and arranged

so that substantially all the vaporized working medium must pass through it to reach the remote end of the

heat output zone of the heat pipe. The vapor is thus separated from the capillary inner walls of the heat output

zone while it is moving in a direction opposed to the liquid flow in these walls. The vapor duct is open at

both ends allowing the vapor to leave the duct at the remote end of the heat output zone. The end of the heat

pipe in the heat output zone has a reentrant arch of rotation configuration which smoothly reverses the vapor

flow and directs the vapor close to the capillary walls of the heat output zone where it condenses. In this way

vapor flow is in substantially the same direction as liquid flow when the vaporized working medium reaches

the capillary walls of the heat output zone.

Heat pipes incorporating the invention can be used to convey heat from a heat source to an area where the

heat is utilized or dissipated. If heat dissipation is desired, fins or other radiating means can be attached to the

exterior of the heat output zone of the heat pipe. For example, heat pipes can be used to cool an electron tube

and other heat sources or to transfer heat to components in the cold environments of space or to a

thermoelectric generator from a radioactive source or other heat source.

No






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Keywords used for search : heat,pipe,capillary,groove



&submit=&patents=on




Invention :

heat pipes

Title of Invention : Heat pipe with capillary groove and floating

artery

Patent No :

Application No : 630236





published) :

4058159



Also Published in:

Inventor Details

Applicant Details

Sr

No


1 . Wilfrido R. Iriarte Long Beach California USA

Sr

No


1 . Wilfrido R. Iriarte Long Beach California USA


Conventional electric motors, and, in particular, squirrel

cage induction motors, generally consist of a stator and a

rotor. Both the stator and rotor are comprised of a core of

magnetic laminations containing conductors typically made

of copper. The stator also includes conductive end turns at

each end of_ its core, while the rotor includes conductive end

caps at its ends.

The present invention relates to electric induction motors.

More particularly, the invention relates to electric induction

motors and related methods of cooling. While the invention

is subject to a wide range of applications, it is especially

suitable for use in an electric vehicle propulsion system; and

will be particularly described in that connection.

In another aspect of the present invention, the above electric vehicle motor further includes a second coolant

inlet in the housing. A rotor having opposite end caps is disposed within the stator core.A second coolant path

begins at thesecond coolant inlet, proceeds to the end caps, and ends at

the coolant outlet. In still another aspect of the present invention, the invention provides an electric motor

including a housing having a pair of end bells, a coolant inlet, and a coolant outlet.

a stator core is encased within the housing and has opposite ends between the end bells. The stator core also

includes a plurality of radial slots extending axially between the opposite ends of the stator core, conductive

windings within the slots, and conductive end turns extending from the slots. The electric motor further

includes at least one shroud disposed within the housing for directing coolant through the slots and towards

the coolant outlet. Each of the at least one shroud extends from one of the opposite ends of the stator core to a

corresponding one of the end bells.

In a further aspect of the present invention, there is

provided a method of cooling an electric vehicle motor including the step of providing coolant to a coolant

inlet of a motor housing, wherein the motor housing has a pair of end bells. The method further includes

directing the coolant through a plurality of radial slots of a stator core. The stator core is encased within the

housing and has opposite ends between the end bells and conductive end turns extending from the slots. The

slots extend axially between the opposite ends of the stator core and contain conductive windings . The

method further includes discharging the coolant from a coolant outlet of the housing.

The present invention relates to electric induction motors.

More particularly, the invention relates to electric induction

motors and related methods of cooling. While the invention

is subject to a wide range of applications, it is especially

suitable for use in an electric vehicle propulsion system; and

will be particularly described in that connection.






An electric motor having a rotor, a stator core and an air gap therebetween, comprising:

a housing including a pair of end bells, a liquid coolant inlet, and a liquid coolant outlet;

a stator core encased within the housing, the stator core having opposite ends between the end bells, a

plurality of radial slots extending axially between the opposite ends, conductive stator windings located

within the slots, and conductive end turnsof the stator windings extending from the slots;

a rotor disposed within said stator core and having opposite end caps.

It will be apparent to those skilled in the art that variousmodifications and

variations can be made in the electric motor and related method of cooling of the

present invention without departing from the spirit or scope of the invention.

Thus, it is intended that the present invention cover the modifications and

variations of this invention provided they come within the scope of the appended

claims and their equivalents.




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Keywords used for search : heat,pipe,Integrated,circuit



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Invention :

Heat pipes

Title of Invention : Integrated circuit heat pipe heat spreader with

through mounting holes

Patent No :






published) :

10/16/2001



Also Published in:

Inventor Details

Applicant Details

Sr

No


1 . Dussinger Peter

M.

Lititz, PA

1 . Myers Thomas L. Lititz, PA

Sr

No


1 . Thermal Corp. Georgetown, DE Georgetown US


As integrated circuit chips decrease in size and increase in power, the required heat sinks and heat spreaders

have grown to be larger than the chips. Heat sinks are most effective when there is a uniform heat flux

applied over the entire heat input surface. When a heat sink with a large heat input surface is attached to a

heat source of much smaller contact area, there is significant resistance to the flow of heat along the heat

input surface of the heat sink to the other portions of the heat sink surface which are not in direct contact with

the contact area of the integrated circuit chip. Higher power and smaller heat sources, or heat sources which

are off center from the heat sink, increase the resistance to heat flow to the balance of the heat sink. This

phenomenon can cause great differences in the effectiveness of heat transfer from various parts of a heat sink.

The effect of this unbalanced heat transfer is reduced performance of the integrated circuit chip and decreased

reliability due to high operating temperatures.

The brute force approach to overcoming the resistance to heat flow within heat sinks which are larger than

the device being cooled is to increase the size of the heat sink, increase the thickness of the heat sink surface

which contacts the device to be cooled, increase the air flow which cools the heat sink, or reduce the

temperature of the cooling air. However, these approaches increase weight, noise, system complexity, and

expense.

It would be a great advantage to have a simple, light weight heat sink for an integrated circuit chip which

includes an essentially isothermal surface even though only a part of the surface is in contact with the chip,

and also includes a simple means for assuring intimate contact with the integrated circuit chip to provide

good heat transfer between the chip and the heat sink.

The internal structure of the heat pipe is an evacuated vapor chamber with a limited amount of liquid and

includes a pattern of spacers extending between and contacting the two plates or any other boundary structure

forming the vapor chamber. The spacers prevent the plates from bowing inward, and therefore maintain the

vital flat surface for contact with the integrated circuit chip. These spacers can be solid columns, embossed

depressions formed in one of the plates, or a mixture of the two. Porous capillary wick material also covers

the inside surfaces of the heat pipe and has a substantial thickness surrounding the surfaces of the spacers

within the heat pipe, thus forming pillars of porous wick surrounding the supporting spacers. The wick

material therefore spans the space between the plates in multiple locations.

The spacers thus serve important purposes. They support the flat plates and prevent them from deflecting

inward and distorting the plates to deform the flat surfaces which are required for good heat transfer. The

spacers also serve as critical support for the portions of the capillary wick which span the internal space

between the plates. The capillary wick pillars which span the space between the plates provide a gravity

independent characteristic to the heat spreader, and the spacers around which the wick pillars are located

assure that the capillary wick is not subjected to destructive compression forces.

The spacers also make it possible to provide holes into and through the vapor chamber, an apparent

inconsistency since a heat pipe vacuum chamber is supposed to be vacuum tight. This is accomplished by

bonding the spacers, if they are solid, to both plates of the heat pipe, or, if they are embossed in one plate,

bonding the portions of the depressions which contact the opposite plate to that opposite plate. With the




spacer bonded to one or both plates, a through hole can be formed within the spacer and it has no effect on

the vacuum integrity of the heat pipe vapor chamber, from which the hole is completely isolated.

An alternate embodiment of the invention provides the same provision for mounting the heat pipe heat

spreader with simple screws even when the heat pipe is constructed without internal spacers. This

embodiment forms the through holes in the solid boundary structure around the outside edges of the two

plates. This region of the heat pipe is by its basic function already sealed off from the vapor chamber by the

bond between the two plates, and the only additional requirement for forming a through hole within it is that

the width of the bonded region be larger than the diameter of the hole. Clearly, with the holes located in the

peripheral lips, the heat pipe boundary structure can be any shape.

Another alternate embodiment of the invention provides for improved heat transfer between the integrated

circuit chip and the heat pipe heat spreader. This is accomplished by using a different capillary wick material

within the heat pipe at the location which is directly in contact with the chip. Instead of using the same

sintered copper powder wick which is used throughout the rest of the heat pipe, the part of the wick which is

on the region of the heat pipe surface which is in contact with the chip is constructed of higher thermal

conductivity sintered powder. Such powder can be silver, diamond, or many other materials well known in

the art. This provides for significantly better heat transfer in the most critical heat transfer area, right at the

integrated circuit chip.

The apparatus is a heat pipe with superior heat transfer between the heat pipe and the heat source and heat

sink. The heat pipe is held tightly against the heat source by mounting holes which penetrate the structure of

the heat pipe but are sealed off from the vapor chamber because they each are located within a sealed

structure such as a pillar or the solid layers of the casing surrounding the vapor chamber. Another feature of

the heat pipe is the use of more highly heat conductive material for only that part of the wick in the region

which contacts the heat source, so that there is superior heat conductivity in that region.

The present invention is an inexpensive heat pipe heat spreader for integrated circuit chips which is of simple,

light weight construction. It is easily manufactured, requires little additional space, and provides additional

surface area for cooling the integrated circuit and for attachment to heat transfer devices for moving the heat

away from the integrated circuit chip to a location from which the heat can be more easily disposed of.

Furthermore, the heat pipe heat spreader is constructed to assure precise flatness and to maximize heat

transfer from the heat source and to the heat sink, and has holes through its body to facilitate mounting.

The heat spreader of the present invention is a heat pipe which requires no significant modification of the

circuit board or socket because it is held in intimate contact with the integrated circuit chip by conventional

screws attached to the integrated circuit mounting board. This means that the invention uses a very minimum

number of simple parts. Furthermore, the same screws which hold the heat spreader against the chip can also

be used to clamp a finned heat sink to the opposite surface of the heat spreader.






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Keywords used for search : heat,pipe,evoporator,condenser



+condenser+evoporator&submit=&patents=on




Invention :

Heat pipes

Title of Invention : Improved Heat pipes

Patent No :






published) :

09/14/1971



Also Published in:


Inventor Details

Applicant Details

Sr

No


1 . Feldman Jr. Karl

T.

Bernalillo, NM

1 . Feldman Jr. Karl

T.

Bernalillo, NM

1 . Kusianovich John

D.

Bernalillo, NM

Sr

No


1 . Energy

Conversion

Systems, Inc.

Albuquerque, NM Albuquerque US


This invention relates to improvements in heat pipes. In particular, it relates to new and novel means for

transferring vaporized heat exchange fluid from a heat input source or evaporator to a heat sink or condenser

and returning the condensed fluid to the evaporator. The invention relates in general to an improved, flexible

conveying means between the evaporator and the condenser for the transfer of the heat exchange fluid

between the evaporator and the condenser.

Experience has shown that existing heat pipes are not suitable in applications where heat must be transferred

along nonlinear paths or where either the evaporator or the condenser is subjected to vibration, or where it is

necessary to electrically insulate the evaporator from the condenser, while providing high, thermal

conductivity input and output areas.

Moreover, it has been found that chemical reaction with the working fluid and leakage in the transfer tube

interferes with the operation of the heat pipe. This interference becomes particularly significant in small heat

pipes with a small amount of working fluid. Thus, it is desirable to provide a transfer tube of material that is

chemically inert and of a low porosity. One such material is "Teflon TF RESIN."

In addition, a definite need has arisen in the art for an improved heat pipe capable of providing temperature

control and power flattening.

When used in this application, the term "thermal power flattening" refers to the ability to maintain constant

output heat flux or heat transfer rate per unit area for large variations in the rate of heat input. Temperature

control refers to the ability to maintain nearly constant temperature for large variations in heat transfer rate

through the heat pipe.

It is therefore an object of this invention to provide an improved heat pipe having a flexible fluid transfer tube

between the evaporator and condenser which tube is chemically inert to the working fluid and of a low

porosity.

Other objects and advantages of this invention will be better understood by reference to the drawings and

their accompanying specification wherein:

FIG. 1 is a partial cutaway view of one embodiment of the invention.

FIG. 2 is a cutaway view of a second embodiment of the invention used as a thermal force transducer, as well

as providing flexible heat transport, temperature control, and thermal power flattening.

FIG. 3 is a partial cutaway view of a third embodiment of the invention used for temperature control and for

thermal power flattening.

FIGS. 4 and 5 are cross section views of a fourth embodiment of the invention used in applications where

limited space is available.




Referring now to FIG. 1, it will be seen that the improved heat pipe which comprises this invention consists

of a sealed reservoir or evaporator 10 of high thermal conductivity, a flexible fluid transfer tube 11 and a heat

output reservoir or condenser 12. Evaporator 10 and condenser 12 are well known in the art and their manner

and type of construction is also well known. For efficient operation of the heat pipe, the evaporator and the

condenser must be made of a material of high thermal conductivity for rapid heat exchange. Flexible fluid

transfer tube 11 consists of a flexible pipe 13 which is lined internally with a flexible wick 14 held in place

by a spring or other retaining means 15. Flexible wick 14 extends continuously from evaporator 10 through

flexible fluid transfer tube 11 into condenser 12. A suitable working fluid is provided in the device in a

manner well known in the art. Thus, when heat is applied to evaporator 10, the fluid in wick 14 is evaporated

to a vapor state and travels through flexible fluid transfer tube 11 into condenser 12. The relatively lower

temperature of the condenser causes condensation of the vapor to the liquid state and the resultant removal of

heat. The liquid is absorbed into wick 14 and transferred back to evaporator 10 by capillary action in the

manner well known in the art. The overall heat transfer process approaches constant temperature as a limiting

case.

It is a well-known principal of thermodynamics that a constriction in a vapor flow passage will cause what is

known as a "throttling" effect. This effect is manifest by a drop in temperature in the direction of the vapor

flow and is accomplished by use of a valve or orifice in the vapor flow passage. In order to achieve this effect

and enhance the condensation of the vapor as it passes though flexible fluid transfer tube 11, a clamp or other

squeezing device 16 is provided on the tube. By controlling the internal diameter of fluid transfer tube 11, the

total amount of heat flow through and the temperature drop of the vapor as it passes through the tube can be

controlled.

Spring support 15 retains wick 14 against the inner wall of flexible pipe 13 and thus provides support for the

pipe while at the same time not interfering with its flexibility.

Flexible pipe 13 is made of a material having both low thermal conductivity and high electrical resistance.

Thus, in addition to its normal features, the heat pipe has low thermal loss and low electrical conductance

between evaporator 10 and condenser 12. In addition, flexible pipe 13 is made of a material having a low

porosity and being chemically inert to the working fluid. "TEFLON" is one such material.

The particular embodiment of the invention shown in FIG. 1 is adaptable for uses wherein relative movement

between the evaporator 10 and condenser 12 is necessary or desirable. Moreover, the flexible tube having a

high thermal resistance allows for maximum heat transfer between evaporator 10 and condenser 12 over

nonlinear paths or in other applications where it is necessary or desirable that the evaporator be displaced

from the condenser.

In the modifications shown in FIG. 2, flexible pipe 13 is initially compressed or "accordian" shaped. A wick

19 lines the inner walls of the entire heat pipe to provide the liquid-vapor heat transfer process as has been

previously described. The flexible pipe 13 is initially compressed as shown when no heat transfer is taking

place. Condensation and vaporization of the heat transfer fluid within wick 19 causes expansion and

contraction of the flexible pipe 13 in a "bellows" effect and thus provides a relative movement and force

between the evaporator 17 and condenser 18 which is a function of the amount of heat input to the heat pipe.

The modification shown in FIG. 2 also exhibits the characteristics of the heat pipe shown in FIG. 1.

This particular modification has many uses in the field of temperature and pressure control. The efficient

transfer of heat between evaporator 17 and condenser 18 renders the device extremely accurate for use in

such control systems as that of a space satellite. In the particular modification shown in FIG. 2, the flexible

tube or bellows 13 is initially collapsed as shown and as heat input is increased, it expands as a function of

the increase in temperature, thus acting as a force generating thermometer.

At FIG. 3, a third modification of the invention is shown wherein flexible member 13 is in the form of an

internal bellows and the heat pipe itself is a sealed tube having an evaporator 10 and walls 12 which provide

the condenser or heat rejection function. Wick 14 lines the interior walls of the pipe and provides the liquid-

vapor heat transfer as previously described. As heat is put into the evaporator 10, it causes expansion of vapor

from wick 14 increasing the vapor pressure which in turn causes movement of flexible pipe 13 as a function

of the temperature and the amount of heat supplied. The movement of flexible pipe 13 changes the surface

area of condenser 12 which is exposed to the vapor. The variation in the condenser area results in a constant

amount of heat being rejected to the sink to thus provides thermal power flattening and temperature control.

Another modification of the invention for accomplishing thermal power flattening and temperature control is

shown in FIGS. 4 and 5. This particular modification is useful in many applications where a limited amount

of space is available for housing the heat pipe when in an inoperative position as shown in FIG. 4. The

evaporator 10 is placed at the heat source while the condenser 12 is initially formed in coil to minimize the

space it occupies. The expansion of the vaporized heat transfer fluid into condenser 12 causes condenser 12

to uncoil, thus exposing a greater surface area to the air or other cooling medium so that is as heat is added to

evaporator 10, a greater transfer occurs due to the larger surface area exposed to the cooling medium. The

condensed heat transfer fluid is returned to evaporator 10 by the capillary action of wick 14. Thermal power

flattening and temperature control are thus achieved.

Obviously, many modifications and variations of the present invention are possible in light of the above

teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be

practiced otherwise than as specifically described.

An improved heat pipe having an evaporator and a condenser connected together by a flexible heat transfer

tube lined with a wick, with a clamping means connected to the outer circumference of the flexible heat

transfer pipe for reducing the circumference thereof to thereby restrict the transfer of vaporized heat transfer

fluid from the evaporator to the condenser.

Another object of this invention is to provide an improved heat pipe having a flexible fluid transfer tube

between the evaporator and the condenser which electrically insulates the evaporator from the condenser and

provides a high thermal conductance path between the two.

It is another object of the present invention to provide an improved heat pipe which is adapted for use in

applications requiring relative motion between the evaporator and the condenser sections, and for use in

applications wherein a limited amount of space is available for installation.

It is a further object of this invention to provide a heat pipe which can conduit the working fluid along a

nonlinear path between evaporator and condenser.

It is the further object of this invention to provide an improved heat pipe with a flexible transfer tube between

evaporator and condenser which can generate a mechanical force which is a function of the heat absorbed by

the evaporator for use in applications such as temperature control and thermal power flattening.

It is a further object of this invention to provide a heat pipe which can produce a constant output heat flux for



a wide range of heat input fluxes.

The objects of this invention are achieved by interposing between the evaporator and condenser sections of

the heat pipe a flexible fluid transfer tube having a low porosity and being chemically inert to the working

fluid so that the fluid is transferred in its vapor state from the evaporator to the condenser and returned in

liquid state with a minimum of interference during the passage. The transfer tube is made of a material

having a high electrical resistance and a low thermal conductance to electrically insulate the evaporator from

the condenser and allow a minimum of heat loss through the walls of the transfer tube. The fluid transfer tube

is flexible, allowing for relative movement between the evaporator and the condenser either laterally or

axially.

No




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Keywords used for search : heat,pipe,air,conditioning



+air+conditioning+&submit=&patents=on




Invention :

Heat pipes

Title of Invention : Heat pipes for air conditioning cooling

Patent No : 11/776182






published) :

20080000629



Also Published in:

Relevant Patent / Application No :

Inventor Details

Applicant Details

Sr

No


1 . Viczena George

Sandor

Port Dickson, MY

Sr

No


1 . ALEXANDER R

SCHLEE;SCHLE

E IP

INTERNATIONA

L P.C.

3770 HIGHLAND

AVENUE, SUITE 203,

MANHATTAN BEACH,

CA, 90266, US

California US


With conventional throttle valve controlled cooling coils at part load the latent capacity is reduced much

faster than the sensible capacity, resulting in an increase in space relative humidity and decrease in comfort.

Sensible heat source up stream of the cooling coil other than in the conditioned space does not contribute to

effective sensible load from a latent removal standpoint. The coil needs to be selected at a high water side

pressure drop at full load to ensure turbulent flow in circuits at partial load. The associated control valve

represents equal or higher pressure drop than the coil, resulting in high pump pressure head and considerable

operating cost. Except for employing a reheat device, independent control of sensible versus latent capacity is

not available. Effective treatment of high humidity outside air requires a dedicated air handler. Hot water

heating coils exhibit the same negative characteristics as far as high pressure head and part load

controllability as cooling coils. To measure the energy used by an air handler requires a flow meter also

entering?leaving water temperature differential measurement and accurate, repeatable flow metering is

difficult and costly. Selecting a cooling coil and control valve needs considerable experience despite

sophisticated software selection tools to ensure low load performance and controllability. Water side

balancing of a chilled water system is time consuming and if not performed correctly reflects on system

performance.

Maintain latent capacity at least in proportion to the available sensible load during part load operation down

to zero load.

Utilise sensible heat available in open return air plenum as an effective sensible load to enhance

dehumidification of conditioned space.

Enable low pressure drop coil selection at full load and replace the high pressure drop control valve with a

low differential pressure alternative.

Provide near independent means of part load sensible versus latent capacity control.

Use the same air handler, the same cooling coil that serves the conditioned space to effectively treat high

humidity outside air.

Permit low water side pressure drop heating hot water coil selection at full load, at the same time ensure

controllability at low loads.

Provide an accurate water flow metering option.

Provide optional water system balance indication and a degree of self balancing ability.

Reduce pumping power requirements for new system designs also for retrofit applications.

Ease of coil selection. Assuming the coil selected is large enough to meet full load, part load performance and

controllability is ensured.




In a broad aspect the present invention resides in a control method for chilled water cooling coils and hot

water heating coils used in comfort and industrial air conditioning applications, including:

A movable piston located in the supply header of the coil. At full load the piston is at it''''s upper most

position and all the circuits are active, thus receiving full flow of chilled water. The position of this piston is

dictated by the prevailing sensible heat load on the coil. At partial load the piston is moved down, cutting off

chilled water supply to the circuits above it''''s location.

The percent of active circuits being proportional to the sensible load and the effective coil surface

temperature around the active circuits remaining constant ensures that the latent capacity of the coil is also

proportional to the sensible load.

During part load operation around the upper inactive circuits the coil is at return air dry bulb temperature, no

heat exchange takes place, thus any sensible heat source, be it up or down stream of the cooling coil is an

effective source to enhance dehumidification of the conditioned space. This includes heat generated by light

fittings in open return air plenums.

The coil water side pressure drop at full load may be selected at a low value, as at part load there is no

substantial change in fluid flow velocity in the active circuits and the movable piston presents only minimal

resistance.

Placing another movable piston, this time in the return pipe header of the cooling coil, will facilitate latent

capacity control. For full latent capacity this piston is at it''''s lower most position, below the exit of the lowest

circuit. Elevating this piston the fluid flow is cut off to the circuits below it''''s position. For average space

conditioning coil entering air conditions there is condensate on the higher active portion of the coil. As this

condensate runs down and reaches the low inactive area, it is partly or fully evaporated, resulting in rapid

decrease in latent capacity and due to evaporative cooling an increase in sensible cooling of the air stream.

Thus the piston in the supply pipe header controls sensible capacity by cutting fluid flow to upper circuits and

the piston in the return pipe header, near independently, controls latent capacity by cutting off fluid flow to

the lower most circuits.

Ducting the outside air within the space serving air handling unit to the lower part of the cooling coil, the

same air handling unit may be used to effectively treat humid outside air as well as serve the conditioned

space. The natural limit to this application is having sufficient sensible heat to perform the necessary

dehumidification. Should there be insufficient sensible heat, some kind of reheat needs to be applied, just as it

would in case of a conventional air handling unit dedicated to treat outside air only.

For hot water heating coils the near constant flow in active circuits permits low coil differential pressure

selection at full load with assured low load performance and controllability.

One particular embodiment of this invention employs a weighted piston in the supply pipe header. The

weight of the piston is such as to impose the desired differential pressure across the coil thus ensure constant

flow velocity in the active circuits. The weighted piston is acting as a pressure relief device, on rising

pressure it moves up to expose more circuit entries, thus relieve the pressure and visa versa should the

differential pressure across the coil fall. In this instance there is a low pressure drop external control valve

driven by the sensible load, for example a butterfly valve. The flow velocity in the active circuits being

constant at a fixed differential pressure across the coil, the number of active circuits thus the position of the

piston is directly proportional to the water quantity flowing through the coil. Thus monitoring the position of

this weighted piston gives an accurate, repeatable option to monitor the fluid flow quantity. Addition of

entering and leaving water temperature sensors provides energy monitoring capability.

Monitoring the water flow quantity via the position of this weighted free floating piston also facilitates water

side balancing of the system. Keeping the external control valve full open and throttling the balance valve

until the free floating piston just moves away from it''''s upper most position, indicates that the coil is

precisely at design water flow. All that remains is to lock the balance valve at this particular position.

An optional interlock between the weighted free floating piston and external control valve will add self

balancing capability. It is a limiting type interlock, when the free floating piston in the supply pipe header

reaches it''''s upper most position, the external control valve is prevented from opening up further. Should the

external control valve be wide open at start up, the same interlock commands the valve to close until the

piston drops just below it''''s uppermost position, thus restricting the coil to design chilled water quantity.

During normal operation the external control valve is driven by the sensible load on the coil, however when

the design water flow is exceeded the limiting function takes preference. This self balancing ability is suitable

for chilled and hot water distribution systems where the pressure change from full to minimum system load is

relatively small. For distribution systems where large pressure variations are expected, it is preferred to

include manual balancing valves.

For a new installation the design can incorporate low pressure drop coils and control valves, resulting in

substantial pumping power reduction. In a retrofit application where the original coil is retained, pumping

power reduction is proportional to the pressure head reduction due to the removal of the original high

pressure drop control valve.

Selecting a coil, part load performance need not be considered as there is near constant flow velocity in the

active circuits, thus transition from turbulent to laminar flow and subsequent loss of heat transfer can no

longer take place. A coil suitably sized to meet full load will perform and remain controllable at low partial

loads.

A fluid heat exchanging device, comprising a header and a plurality of interconnecting circuits between an

supply port and a return port, the interconnecting circuits being connected to the header by a corresponding

plurality of connection ports at different locations along the header wherein the header includes a blocking

control element inside the header, the blocking control element being positionally adjustable along the header

to selectively block fluid flow from the supply port through the connection ports of the plurality of

interconnecting circuits, thereby selectively controlling those interconnecting circuits of the plurality of

interconnecting circuits which are subjected to fluid flow therethrough in dependency on the position of the

blocking control element.

The principle of this invention is circuit by circuit control of fluid flow. At full load all the circuits are active,

thus there is fluid flowing through all the available circuits of the coil. At part load the flow of fluid is cut off

to some of the circuits, while flow is maintained at or near full velocity in the active circuits. The number of

active circuits at any given time is determined by the prevailing air side load on the coil. The effective coil

surface temperature around the active circuits remains constant, so dehumidification is maintained at part

load, while around the inactive circuits no heat exchange to the air takes place.





NO


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Keywords used for search : heat,pipe,cooler,

Search String : http://www.freepatentsonline.com/y2006/00603

29.html




Invention :

Heat pipes

Title of Invention : Heat pipes for colling

Patent No :






published) :

US20060060329



Also Published in:



Inventor Details

Applicant Details

Sr

No


1 . Imura Hideaki Kumamoto, Kumamoto

Prefecture, Japan

Kumamoto

Prefecture

Japan

1 . Koito Yasushi Kumamoto, Kumamoto

Prefecture, Japan

Kumamoto

Prefecture

Japan

Sr

No


1 . FUJIKURA LTD. 1-5-1,Kiba, Koto-ku, Tokyo

135-8512,Japan.

Tokyo Japan


In the prior art, a heat pipe, in which a working fluid such as water is encapsulated in a metal pipe excellent

in heat conductivity such as a copper pipe, and which utilizes latent heat generated by a phase change of the

working fluid in the system from a liquid phase to a gas phase, as well as from the gas phase to the liquid

phase, is used for the purpose of removing the heat from equipments, or of heating. For example, those heat

pipes are widely employed for heat exchange in electronic equipments such as a personal computer, and for

local heating of train stations, roadways, points, cars and so on in cold climates.

The most applicable working fluid to meet those requirements is water. However, in a cold condition, water

freezes into ice and its volume expands to cause breakage of the heat pipe. In case the heat pipe comprising

water as the working fluid is used in cold climates, for example, the internal working fluid freezes and

expands, and the expanding pressure may burst the pipe.

The bursting of the pipe can be avoided if Hydrochlorofluorocarbon such as alcohol, hydroflorocarbon or

hydrofluoroether is used in place of water; however, heat conductivity of the alternatives to

chlorofluorocarbon is inferior to that of water.

As a measure for cold climates, an antifreeze liquid is used as the working fluid of automobiles or the like.

The antifreeze liquid is the liquid the freezing point of which is lowered so as not to freeze even below

freezing temperature by adding water with ethylene glycol or propylene glycol. As specified in the

description of Japan Industrial Standard K2234, the widely used antifreeze liquid is made by adding water

with approximately 30 volume percent or 50 volume percent of ethylene glycol and/or propylene glycol, in

order not to freeze even at minus 10 degrees C.

However, if a large amount of ethylene glycol and/or propylene glycol is mixed into water, the boiling point

rises and the viscosity of the working fluid increases to degrade its heat conductivity. As a result of this, the

performance of the heat pipe is deteriorated.

Preferred embodiments of the present invention will be described hereinafter. In FIG. 1, there is shown one

example of the heat pipe according to the invention. According to the heat pipe 1, a working fluid 3 is

encapsulated in a container 2 made of a metallic material such as copper, copper alloy, aluminum, stainless

steel or the like. The container 2 comprises a heating portion 4 and a heat radiating portion 5. A fin 6 or fins

are formed on the heat radiating portion 5. Moreover, inside of the pipe is kept depressurized. Although FIG.

1 shows a wickless heat pipe, which does not have a wick, and in which gravity is used as a motive power,

the present invention can be applied not only to a double-pipe type and a loop type wickless heat pipe, but

also to a heat pipe having a wick.

Basically, water having a large evaporation latent heat is used as the working fluid. The working fluid is

brought to boil and evaporated at the heating portion 4 where a heat source such as a heater is arranged

(heater not shown). At this time, the heat outside of the heat pipe is drawn. The generated vapor ascends in

the heat pipe and liquefies at the heat radiating portion 5. At this time, the heat is radiated. The working fluid

in a liquid phase flows down again in the heat pipe by its own weight to the heating portion 4.




The heat pipe can be operated full-time by activating the heat source, but normally, in view of the efficiency

of thermal energy, it is operated only when needed. As a result of this, in cold climates, there arises a problem

in that the working fluid inside of the heat pipe freezes when the heat pipe is not under operation.

According to the present invention, a liquid comprises the water, to which a certain amount of glycol is

added, as the working fluid to be circulated inside of the heat pipe.

In the present invention, glycols can be exemplified by a low-molecular weight, room-temperature and liquid

organic compound which has hydroxyl groups on both its ends, and specifically by ethylene glycols such as

ethylene glycol, diethylene glycol or triethylene glycol; propylene glycols such as propylene glycol or

dipropylene glycol; and butanediol or the like. A mixture of those liquid organic compounds can also be

applied to the present invention.

The addition amount of glycols for 100 wt % of the working fluid should be in the range from about 0.5 to

about 10 wt %, preferably from about 0.7 to about 5 wt %, and more preferably from about 1.0 to about 3 wt

%. Even if the addition amount of glycols is within the above-mentioned range, it is impossible to prevent the

working fluid from freezing. On the other hand, if the addition amount of glycols exceeds the above-

mentioned ranges, the heat conductivity of the working fluid degrades so that the object of the present

invention cannot be attained.

In order to prevent glycols from deteriorating at high temperature, distilled water containing no metal ions or

deionized water is preferable as the water component in the aqueous solution.

Inventors of the present invention discovered that an aqueous solution containing glycols within the above

ranges freezes into sherbet-like ice containing a solid-liquid mixture, and the strength of the frozen solution is

lowered. Therefore, this does not burst the heat pipe. Moreover, the heat conductivity is also excellent and

comparable to that of the water.

A heat pipe which can prevent frost damage of the pipe body due to freezing of the typical working fluid in

cold climates by encapsulating an aqueous solution containing about 0.5 to about 10 wt % glycols as a

working fluid, and which has a working performance almost comparable to that of the heat pipe in which

water is used as the working fluid.

A main object of the present invention is to provide a heat pipe in which the frost damage of the pipe body

due to freezing of the working fluid in cold climates is prevented.

Another object of the present invention is to provide a heat pipe having a comparable working performance

to that of the heat pipe using water as the working fluid.

Still another object of the present invention is to provide a heat pipe excellent in heat conductivity.

According to the present invention, therefore, there is provided a heat pipe wherein water containing about

0.5 to about 10 wt % glycols is used as the working fluid.

According to the present invention, moreover, ethylene glycol and/or propylene glycol is/are preferable as the

aforementioned glycol.



According to the present invention, still moreover, distilled water or deionized water is preferable as the

water.

NO




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Database:


Keywords used for search : heatpipe,die,center,point, loading


ort=relevance&srch=top&query_txt=heatpipe+a

ttachment+to+die+using+center+point+loading

&submit=&patents=on




Invention :

Heatpipes

Title of Invention : DIRECT HEATPIPE ATTACHMENT TO DIE

USING CENTER POINT LOADING

Patent No : WO/2002/027785

Application No : PCT/US2001/030367





published) :



Also Published in:

Relevant Patent / Application No : H01L 23/00

Applicant for Patent is : Organization

Inventor Details

Applicant Details

Sr

No


1 . Sathe, Ajit 820 North Granada Drive,

Chandler, AZ, 85226

Chandler USA

1 . Frutschy,

Kristopher

2515 Rockledge Road,

Phoenix, AZ, 85048

Phoenix USA

1 . Distefano, Eric 1535 Frankfurt Way,

Livermore, CA, 94550

Livermore USA

Sr

No


1 . Sathe, Ajit 820 North Granada Drive,

Chandler, AZ, 85226

Chandler USA

1 . Frutschy,

Kristopher

2515 Rockledge Road,

Phoenix, AZ, 85048

Phoenix USA

1 . Distefano, Eric 1535 Frankfurt Way,

Livermore, CA, 94550

Livermore USA


In the design and manufacture of computer hardware, meeting certain thermal requirements can be essential.

In particular a silicon microchip (die) placed into a circuit package, can have a requirement to remove heat

generated by the microchip during operation. The circuit package may have a barrier of plastic covering the

die. In the case of laptop computers, a heatpipe acting as a heat conductor may be attached to the circuit

package containing the die to help carry off the heat.

A heatpipe is a heat transfer structure that includes a number of channels for transferring heat to a condenser

region. Each heatpipe is composed of a central vapor channel with a number of parallel capillary channels,

each of which is open on one side to the vapor channel thereby serving as the wick of the heat pipe, running

the length of the circuit board to a condenser region. The heat from the microchip vaporizes a working fluid

in the capillaries and the vapor, in turn, travels in the vapor channel to a condenser region to be cooled and

condensed by a cooling medium, such as air, over this region.

When a heatpipe is used, a heatpipe surface contacting the circuit package typically has a cross-section

smaller than the circuit package it contacts and a portion of the circuit package extends out beyond the

heatpipe edges. As a result, heat transfer may not be as efficient as required and a thermal adaptor such as a

spreader plate can be used. To improve thermal conduction between the heatpipe and the circuit package, the

spreader plate has a surface area and shape that can more closely match with the heatpipe. The spreader plate

is positioned between the heatpipe and the circuit package.

A novel structure and method for providing a balanced clamping force to a vapor chamber directly attached

to a die or a circuit package is disclosed. In the following description numerous specific details are set forth

such as specific materials, equipment, and processes in order to provide a thorough understanding of the

present invention. In other instances, well known computer assembly techniques and machinery have not

been set forth in detail in order to minimize obscuring the present invention.





























The present invention is a novel structure and method for directly attaching a vapor chamber to the die or the

circuit package having a single thermal interface material in between. In addition, the present invention is a

novel structure and method to fabricate uniform thermal interface material thicknesses having minimal voids

and gaps by providing a centered point force (centerpoint force) that results in a balanced clamping force.

In particular for portable computers, the need for a spreader plate may not be

necessary and the vapor chamber may be connected directly to an individual die.

With this approach, the vapor chamber is not separated from the die by a plastic

layer of the circuit package that could act as a thermal barrier and the vapor

chamber can directly conduct heat off the die surface. A heatpipe could also serve

this purpose if it is wide enough and stiff enough.





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Keywords used for search : underfloor,heating,apparatus,


ort=relevance&srch=top&query_txt=underfloor

+heating&submit=&patents=on




Invention :

Heatpipes

Title of Invention : AN UNDERFLOOR HEATING APPARATUS

Patent No : WO/2003/002916

Application No : PCT/GB2002/002860





published) :


First Filled Country :

Also Published in:


Inventor Details

Applicant Details

Sr

No


1 . Lamb, Leo 27 Marford Road West

Derby Liverpool L12 5HH

Liverpool UK

Sr

No



Derby Liverpool L12 5HH

Liverpool UK


It is known to provide underfloor heating systems such as hot water pipes that extend beneath an area of

floor. However, the installation of such systems is difficult due to the need to remove the floorboards and

create sufficient space beneath for the apparatus to fit into the underfloor cavity.

It is an object of the present invention to provide an improved underfloor heating apparatus that overcomes,

or at least alleviates, the abovementioned drawbacks

Accordingly, the present invention provides an underfloor heating apparatus comprising at least one conduit

for transporting a heat transfer medium therethrough, at least one heatpipe contactable with said conduit and

means for adjusting the positioning of the heatpipe relative to the conduit.

In the context of this disclosure, a heatpipe is a partially evacuated, self-contained unit that contains a small

amount of working fluid and preferably has means, such as a valve, for evacuation thereof. The working fluid

is preferably water.

In the context of this disclosure, a heatpipe is a partially evacuated, self-contained unit that contains a small

amount of working fluid and preferably has means, such as a valve, for evacuation thereof. The working fluid

is preferably water.

The conduit is preferably in the form of a pipe that is connected to the conventional heating system.

Preferably, the pipe has hot water transported therethrough. The water may be heated by, for example, an

electric immersion heater or a gas boiler.

Contact between the heatpipes and the conduit is preferably maintained by means of a bracket. Preferably, the

bracket comprises a cylindrical sleeve having a cylindrical branch extending therefrom.

The sleeve may be fitted over the main conduit and the heatpipe may be fitted into the open end of the

cylindrical branch. The heatpipe may be fixedly secured to the bracket or be detachable therefrom.

The sleeve is preferably slidable and rotatable about the main conduit to enable the positioning of the

heatpipe relative to the conduit to be adjusted. Suitable fixing means may be provided for retaining the

bracket in a desired position with respect to the main conduit and for retaining the heatpipe within the branch.

More preferably, the sleeve and the branch extending therefrom are dimensioned to be substantially the same

size as the part that fits therein, i. e. the main conduit or heatpipe. Preferably the sleeve and branch are each

provided with a slit or cut therethrough to enable that section to be fitted over or receive the respective

component part. Suitable fastening means, such as Allen screws and keys, may be used across said slit or cut

to clamp the components within the bracket. Preferably, the sleeve is provided with a longitudinal slit along

the length thereof. The branch is preferably provided with at least one, preferably two, slits at right angles to

the slit in the sleeve.

Preferably, the bracket is formed by means of a cast moulding.




An underfloor heating system having a main conduit (2) transporting a heat transfer medium therethrough, at

least one heatpipe (4) contactable with said conduit, said heatpipe having means (6) for adjusting its

positioning relative to the conduit

Referring to the accompanying drawings, an underfloor heating apparatus according to one embodiment of

the present invention is illustrated. The apparatus comprises a main pipe or conduit 2 that transports a heat

transfer medium, such as hot water from the conventional heating system of a building, and a plurality of

heatpipes 4. The water may be heated by means of for example, an electric immersion tank or a gas boiler.

Each heatpipe is a self- contained, sealed pipe that is partially evacuated and contains a small amount of

working fluid, such as water.

A series of T-shaped cylindrical brackets 6 are provided at spaced apart intervals along the length of the

conduit. The brackets comprise a main cylindrical sleeve 6a that is dimensioned to fit over the main conduit 2

and a cylindrical branch 6b extending substantially perpendicularly from the sleeve 6a for receiving the

heatpipe. The sleeve 6a is provided with a longitudinal slit 8 therethrough (see Figure 2) and the branch

extension 6b has two horizontal slits 10 through opposing sides of the branch (see Figure 3). The longitudinal

slit enables the sleeve of the bracket to be slid onto the main pipe and fastened thereto using, for example, an

Allen screw and key. Similarly, the horizontal slits enable a heatpipe to be placed in the open end of the

branch extension and clamped therein by fastening means, such as an Allen screw and key. This ensures that

the heatpipe has adequate contact with the bracket and main pipe.

In this manner, the hot water that is transported through the main conduit 2 is able to heat up the working

fluid in the heatpipes extending therefrom. The working fluid evaporates below its normal boiling point due

to the low pressure (preferably at least 29.82 inches Hg, 100982.14 Nm-2, more preferably at least 29.85

inches Hg, 101083.74 Nm-2) that exists inside the heatpipes. The reduced pressure inside the heatpipes also

allows the fluid to move rapidly therethrough and, as it does so, condenses to release its latent heat of

condensation thereby transferring heat to the walls of the pipe and hence, its surroundings. The working fluid

is re-circulated to provide a continuous source of heating.

The brackets used in the apparatus of the present invention enable the heatpipes to be positioned at any

desired location along the length of the main pipe, for example, depending upon the positioning of any

obstructions in the floor space. Similarly, the angle of the heatpipe relative to the main pipe may be adjusted

by rotation of the bracket such that the branch, and therefore, heatpipe, extends from the main pipe at the

desired angle. The bracket is then secured at the required angle and location by the fastening means.

the hot water that is transported through the main conduit 2 is able to heat up the working fluid in the

heatpipes extending therefrom. The working fluid evaporates below its normal boiling point due to the low

pressure (preferably at least 29.82 inches Hg, 100982.14 Nm-2, more preferably at least 29.85 inches Hg,

101083.74 Nm-2) that exists inside the heatpipes. The reduced pressure inside the heatpipes also allows the

fluid to move rapidly therethrough and, as it does so, condenses to release its latent heat of condensation

thereby transferring heat to the walls of the pipe and hence, its surroundings. The working fluid is re-

circulated to provide a continuous source of heating.

The brackets used in the apparatus of the present invention enable the heatpipes to be positioned at any

desired location along the length of the main pipe, for example, depending upon the positioning of any

obstructions in the floor space. Similarly, the angle of the heatpipe relative to the main pipe may be adjusted



by rotation of the bracket such that the branch, and therefore, heatpipe, extends from the main pipe at the

desired angle. The bracket is then secured at the required angle and location by the fastening means.

No


Patent Status : Published Application


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Keywords used for search : heatpipe,cooling,heating,buildings


ort=relevance&srch=top&query_txt=heatpipe+f

or+heating+of+buildings&submit=&patents=on




Invention :

Heatpipe

Title of Invention : HEAT TRANSFER SYSTEM,

PARTICULARLY FOR USE IN THE

HEATING OR COOLING OF BUILDINGS

Patent No : WO/2000/070286

Application No : PCT/GB2000/001781





published) :


First Filled Country : United Kingdom

Also Published in:

Inventor Details

Applicant Details

Sr

No



Derby Liverpool

Merseyside L12 5HH

Liverpool UK

Sr

No



Derby Liverpool

Merseyside L12 5HH

Liverpool UK


A number of systems exist for heating a building, such as a hot water or gas heating systems. A hot water

heating system uses water as the medium for transporting heat around a building. The water is heated in a

boiler and is delivered via pipes to radiators situated at intervals throughout the building. The system may

rely on gravity for the movement of the water through the system, i. e., the heated water becomes less dense

and rises up the pipes and is delivered to radiators as it flows back down through the pipes or alternatively an

electric pump may be installed in either the flow pipe or return pipe to pump the hot water around the system.

The flow of hot water through the radiators results in the release of heat therefrom by means of radiation,

convention, and conduction thereby heating the surroundings of the radiator.

The temperature conveyed by a hot water heating system may be controlled by means of a central thermostat

set to a desired temperature. When the actual temperature of the system rises above or falls below the desired

temperature the flow of hot water to the radiators or the firing of the boiler is adjusted accordingly. The

temperature of the radiator may also be adjusted by means of a separate thermostat provided on the

radiator.Further disadvantages associated with conventional heating systems are that the radiators are bulky

and expensive. The radiators are also difficult to move once installed in a particular location due to the main

water pipes being provided with auxiliary pipework for the delivery of water to the radiator in the regions

where radiators are to be located in a particular building. Thus, changing the positioning of a radiator would

require substantial alterations to the pipework of the system. The heavy nature of the radiator dictated by the

radiator having to potentially withstand high pressures also means that the radiator has to be fixed to a wall

by substantial fastening means resulting in the radiator being difficult to remove at a later date. Thus, the

provision of a heating system which uses conventional radiators having convoluted pipes contained within

the body of the radiator generally restricts the positioning of the radiator to the location it was originally

installed.

It is an object of the present invention to provide an improved heat transfer system, particularly for the

heating or cooling of buildings, which aims to overcome the abovementioned drawbacks.

Accordingly, the present invention provides a heat transfer system comprising a conduit for transporting a

heat transfer medium and an at least partially evacuated self-contained unit in contact with the conduit, the

unit having an interior cavity for receiving a fluid whereby heat is transferred to or from the heat transfer

medium to or from the fluid in the unit.

Preferably, the conduit is in the form of a pipe. The heat transfer medium may be, for example, water or gas.

Preferably, the pipe transports water around a building which has been heated by means of a boiler.

Alternatively the conduit may be in the form of an electric pipe, the pipe being heated, for example by means

of coils around the pipe.

In an alternative embodiment of the present invention, the unit is comprised of one or more heatpipes that are

placed in contact with the conduit transporting the heat transfer medium. More preferably, the individual

heatpipes are contained within a manifold that is attached to the conduit, the manifold having a plurality of

channels for receiving the heatpipes. Alternatively, a longitudinal element may be provided for surrounding

or contacting the heating element, the longitudinal element being provided with means for supporting the




individual heatpipes. For example, the element may have an upwardly open bracket along the length thereof

or a series of brackets extending upwardly therefrom for receiving the heatpipes to keep the heatpipes in

contact with the heating element. The longitudinal element is preferably in the form of an extrusion.

It is preferable to provide a casing over the unit. More preferably, the casing is provided with lower and

upper airflow holes to allow air to enter the bottom of the unit and leave through the upper airflow holes

thereby enabling the unit to transfer heat by means of convection and radiation. Preferably, a fan is provided

within the casing to assist in circulation of the air. The casing may be formed integrally with the heatpipes.

It is to be appreciated that the system may be used to effect cooling of the surroundings by supplying warm

air to the heatpipes wherein the warm air transfers its heat energy to the working fluid in the pipes and

thereby cools the air which is then released from the unit. The ability of the system to work as a heating or

cooling system would be dictated by the temperature of the heatpipes compared with the temperature of the

surroundings.

The unit may be provided with a secondary heat source whereby if the heat- conducting medium in the

conduit should fail, the heatpipes may still be heated to effect heating of the radiator and the surroundings.

For example, an electrical heating element may be attached to the heatpipes for connection to an electrical

supply, when required.

The unit may be made of any appropriate heat conducting material, such as aluminium or steel. The interior

cavity of the unit is preferably provided with strengthening elements to prevent the collapse thereof under

vacuum, particularly in embodiments having a large interior cavity. For example, the cavity may be provided

with rings of stiffening tubes at spaced apart intervals.

A heat transfer system comprising a conduit for transporting a heat transfer medium and an at least partially

evacuated self-contained unit in contact with the conduit, the unit having an interior cavity for receiving a

fluid whereby heat is transferred to or from the heat transfer medium from or to the fluid in the unit. The

system may comprise a series of upright heatpipes in contact with a water pipe, the heatpipes being housed

within a manifold.

The heating apparatus of the present invention has a number of advantages over those of the prior art. Firstly,

the radiator does not require internal pipework for the flow of water therearound. This reduces the pressure

on the pump of the heating system since it no longer has to pump the water around the convoluted pipes of

the radiator. The radiator may also be fastened to a heat pipe at any suitable location, thus greatly increasing

the flexibility of the location of the radiator. Additionally, the radiator will normally operate at negative

pressures up to approximately 100°C depending on the fluid in the radiator. Thus, the radiator will only have

to withstand low pressures even at high temperatures. In contrast, the radiators of the prior art always have a

positive pressure which increases as the temperature of the medium in the radiator rises. Not only does this

result in the radiator of the present invention being safer to use but the radiator may also be made of a lighter

and thinner material due to the reduced pressure of the interior of the radiator caused by the partial vacuum.

The radiator does not require the large number of valves and taps nor decommissioning of the boiler which

are required with the conventional heating systems. A reduced volume of water also has to be heated and

transported around the building thereby providing a far more efficient heating system. The heating system of

the present invention may also be applied to existing pipework in buildings, thereby enabling the adaptation

of old systems to that of the present invention.




No



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Keywords used for search : Heat,Pipe,Cooling,multichip


ort=relevance&srch=top&query_txt=Heatpipe+

for+cooling&submit=&patents=on




Invention :

Heatpipes

Title of Invention : Method and apparatus for cooling multi-chip

modules using integral heatpipe technology

Patent No : EP0529837

Application No : EP19920307161





published) :


First Filled Country :

Also Published in:

Inventor Details

Applicant Details


An important objective of computer design is to fit the greatest number of semiconductor chips or ICs into

the smallest space. Factors such as substrate design, interconnect design, cooling method, density of chip

placement, etc., have great bearing on the ultimate performance of the computer. The tendency of designers

to minimize the size of the computer while maximizing its computing power has led to more and more

densely packed IC chips. The density of interconnects that provide the signal path between ICs must

concurrently rise. Unfortunately, these densely networked interconnects have a propensity to generate heat.

In earlier days, the circuits were simply cooled by air convection circulated by a fan. But when the fan was

used in conjunction with high density, multi-chip, main frame computers, the large volume of air needed for

cooling necessitated powerful blowers and large ducts. Such clumsy structures in the computer occupied

precious space and were noisy too.

when the multi-chip module is mounted to the motherboard, it is inverted such that the semiconductor chips

and their electrical interconnects are directly connected to the motherboard and the heatpipe consequently

becomes situated at the top. In this inverted orientation, heat rises naturally upward through the heat sink and

heatpipe and out into the ambient environment.

The present invention relates to a multi-chip module circuit board cooled by an integrated heatpipe. The

multi-chip module just prior to installation of the heatpipe. A packaging substrate is provided to hold a

plurality of semiconductor chips. In a preferred embodiment of the present invention, the packaging substrate

contains a network of cavities which extend completely through the thickness of the substrate. Through

various methods known in the art, semiconductor chips are inserted into these cavities. Electrical

interconnects (not shown) provided on the chips and the packaging substrate top face allow electrical

communication among the chips and facilitate electrical interface with external devices.After installation, the

semiconductor chips should preferably be recessed into the substrate such that their bottom surfaces are

exposed. A thermal conduction means, embedded into the bottom face of the packaging substrate, is adapted

to engage the bottom surfaces of the chips. An interference fit is sufficient to mechanically hold the thermal

conduction means in place. Other means of attachment such as cement, mechanical fasteners, or other means

known in the art are suitable to hold the conduction means in position. Positive engagement is thus obtained

between the bottom of each chip against the thermal conduction means. In the preferred embodiment, the

thermal conduction means is a copper slug. Clearly, other thermo conducting devices known in the art are

acceptable in place of the copper slug.

A method and apparatus for cooling a multi-chip module with an integrated heatpipe. Multiple semiconductor

chips are embedded in a packaging substrate with electrical interconnects disposed on one side while a heat

sink incorporated into the substrate on the other side and abutting the semiconductor chips on their underside.

A heatpipe is directly mounted to the heat sink. Inside the heatpipe is a chamber containing a coolant and a

wick.

The present invention relates to the management of latent heat energy build up within a multi-chip module

package that requires exceptional cooling during operation. The present invention relies on heatpipe






technology. Heatpipe technology has been used successfully for many years in moving and dispersing built-

up heat in harsh environments. Indeed, this form of thermal management has been applied in the space shuttle

program successfully for many years.

The present invention integrates a heatpipe directly into a multi-chip module (i.e., MCM) substrate, and is

thus not simply bolted on. This is distinct from some of the prior art devices, which add discrete cooling

structures to the MCM substrate. By embedding the heatpipe directly to the MCM via a thermal conduction

means, it is much simpler for product assembly and possible rework.

In a preferred embodiment, the present invention provides a heatpipe made out of copper or aluminum

tubing. It can be round or flat. It can also be made from forming the metal into various other shapes. The

heatpipe has a saturated wick inside that holds a working fluid, or coolant. The coolant boils and vaporizes

when it comes in contact with heat energy radiating from the ICs.

The heatpipe has several functioning parts. Inside the heatpipe is the wick engulfed in coolant. The coolant

moves into an evaporator region of the heatpipe, which region is disposed nearest to the ICs, and vaporizes

due to the heat. The resulting vapor then travels along the heatpipe and condenses inside a condenser region,

disposed away from the heat source, as it is cooled by ambient conditions. Afterward, the condensate returns

to the evaporator region by capillary action through the wick.

The above-mentioned cycle is a closed loop type, never ending so long as there is heat energy being applied.

In fact, the cycle is somewhat akin to a refrigeration cycle.

An MCM package cooled by the present invention is not as prone to coolant leakage because the coolant is

contained within the substrate thus minimizing the possibility of contamination with the chips. Further, the

simplified construction of the cooling mechanism ensures that the present invention is less expensive to build

than the prior art cooling devices. Also, positive contact between the cooling mechanism of the present

invention and the IC chips results in efficient heat conduction as compared to the prior art devices that

required various make-shift hardware to obtain positive contact.

In an alternate embodiment (not shown), the heatpipe can extend to one side of

the thermal conduction means. In this disposition, the entire region proximal to the

thermal conduction means functions as a evaporator while the distal portion away

from the thermal conduction means and not in engagement therewith functions as

a condenser.




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Keywords used for search : heatpipe,single,extruded,heat , sink


ort=relevance&srch=top&query_txt=heatpipe+f

or+heat+sink&submit=&patents=on




Invention :

Heatpipes

Title of Invention : Heat sink made from a singly extruded heatpipe

Patent No : US 7195058 B2






published) :

US 7195058 B2


First Filled Country : USA

Also Published in:


Inventor Details

Applicant Details

Sr

No


1 . Wolford, Robert

Russell

Raleigh, NC Raleigh US

1 . Foster Sr. Jimmy

Grant

Morrisville, NC Morrisville US

1 . Hardee, Donna

Casteel


1 . Keener, Don

Steven

Apex, NC Apex US

Sr

No


1 . Wolford, Robert

Russell


1 . Foster Sr., Jimmy

Grant


1 . Hardee, Donna

Casteel


1 . Keener, Don

Steven

Apex, NC Apex US

1 . Wolford, Robert

Russell


1 . Foster Sr., Jimmy

Grant


1 . Hardee, Donna

Casteel


1 . Keener, Don

Steven

Apex, NC Apex US


In a typical personal computer (PC), the main heat-generating component among the logic circuits is the

processor, also referred to as the Central Processing Unit (CPU) or microprocessor (MP). As illustrated in

FIG. 1a, a processor 102 is mounted in a socket 104, which is mounted on a (printed) circuit board 106, by

mating pins 108 from the processor 102 into the socket 104. As processors continue to grow in performance,

so does the heat generated by the processors. This heat, if excessive, can cause the processor 102, or any

other similar Integrated Circuit (IC) package, to malfunction or fail entirely

To remove heat from processor 102, a heat sink (HS) 110, having a HS base 112 and a plurality of fins 114,

is secured to processor 102 by a strap 116 or other attachment means. Heat is conducted from the processor

102 to the HS base 112 and the fins 114, which dissipate heat by conduction and convection to ambient air

surrounding fins 114. To provide thermal conduction between a top surface 120 of processor 102 and the HS

base 112, a thermal grease 118, typically a thermally conductive silicon or filled hydrocarbon grease doped

with fillings such as metals, is used.

A major problem with the heat sink 110 shown in FIG. 1a is that it relies on conduction to the ambient air,

which may or may not be moving enough to significantly convey away heat, depending on movement of air

about the heat sink caused by fan(s) in a computer case that houses the processor 102. To aid in this air

movement, the prior art provided the improvement of a heat sink fan 122, as shown in FIG. 1b. As shown,

heat sink fan 122 includes fan blades 124 that rotate about a hub 126.

As IC''''s became even denser with more and more transistors and other electronic components, the heat sink

configurations shown in FIGS. 1a?b became insufficient to remove damaging heat from IC packages such as

that shown for processor 102. The next step-up in prior art heat removal technology was the development of a

heat sink that incorporated a pipe filled with a heat-transferring fluid. This type of heat sink is known as a

?heatpipe.? With reference now to FIG. 2a, a prior art heatpipe 200 is depicted. Heatpipe 200 is composed of

a heatpipe base 202, which is adjacent to processor 102, with or without intermediary thermal grease 118. As

shown in FIGS. 2a?c, attached to heatpipe base 202 is a pipe 204, from which a plurality of horizontal fins

206 extends. Horizontal fins 206 convectively remove heat away from pipe 204, in a manner similar to that

described for fins 114 described in FIGS. 1a?b. However, heatpipe 200 utilizes fluid heat transfer as well.

As shown in FIG. 2c, pipe 204 is filled with a fluid 208, which is retained inside of pipe 204 by a pipe cap

210. As depicted by the flow arrows in FIG. 2c, fluid 208 circulates in a vertical manner within pipe 204.

That is, as fluid 208 is heated at the bottom of pipe 204, which is adjacent heatpipe base 202 and thus the heat

producing processor 102, fluid 208 rises upwards towards a pipe cap 210 at the top of pipe 204. When fluid

208 reaches pipe cap 210, fluid 208 flows back down the interior sides of pipe 204. The sides of pipe 204 are

able to conduct away heat from fluid 208, since the horizontal fins 206 provide additional

conduction/convection cooling from the sides of pipe 204 to the ambient air.

While the heatpipe 200 depicted in FIGS. 2a?c was a great improvement over prior art heat sinks, the

construction of heatpipe 200 is cumbersome. Each component of heatpipe 200 must be individually

fabricated, and the entire heatpipe 200 then assembled. That is, heatpipe base 202, pipe 204, horizontal fins

206 and pipe cap 210 must each be separately fabricated, and then the pieces are bonded together to form the




final heatpipe 200. One of the most onerous steps in the fabrication/assembly process for heatpipe 200 is the

attachment of horizontal fins 206 to pipe 204. After aligning each of the horizontal fins 206 with pipe 204,

the horizontal fins 206 are bonded (usually with heat welding or a similar process) to pipe 204. This process

is expensive, time consuming, and difficult to meet quality control parameters.

A heatpipe for cooling an integrated circuit. The heatpipe includes a pipe and radial fins that are formed by

extruding a single piece of material, such as heat conducting metal. Each of the radial fins extends away from

the pipe and runs (preferably) the length of the pipe. Each radial fin has normally oriented subfins that

provide additional heat convection surface areas to the radial fins. Within the pipe are interior fins, also

formed during the material extrusion process. The interior fins provide additional conduction cooling to a

heat transferring fluid circulating within the pipe.

The present invention is therefore directed to a heatpipe for cooling an integrated circuit. The heatpipe

includes a pipe and radial fins that are formed by extruding a single piece of material, such as heat conducting

metal. Each of the radial fins extends away from the pipe and (preferably) runs the length of the pipe. Each

radial fin has normally oriented subfins that provide additional heat convection surface areas to the radial

fins. Within the pipe are interior fins, also formed during the material extrusion process. The interior fins

provide additional conduction cooling to a heat transferring fluid circulating within the pipe.

The above, as well as additional objectives, features, and advantages of the present invention will become

apparent in the following detailed written description.

No






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>91%


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