US3468300A - Heat transfer means for a railway tank car - Google Patents

Description

Sept. 23, 1969 w. T. GEYER E AL ,463, 0

HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR Filed Nov. 13, 1968 12 Sheets-Sheet l FIG.

' INVENTORS. WALLACE T. GEYER EDWARD L. COYLE ATTORNEY Sept. 23, 1969 w. T. GEYER ET AL 3,468,300

HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR Filed Nov. 13, 1968 12 Sheets-Sheet r,

0 u 40 AL Mm l 38 I I I II 4 ill' p 196g w. T. GEYER E AL 3,468,300

HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR Filed Nov. 13, 1968 12 Sheets-Sheet Z- Sept. 23, 1969 w. T. GEYER ET HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR Filed Nov. 13, 1968 12 Sheets-Sheet 4 Sept. 23, 1969 w. T. GEYER ET HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR 12 Sheets-Sheet 5 Filed Nov. 13, 1968 Sept. 23, 1969 w. T. GEYER ET AL 3,468,300

HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR Filed Nov. 13, 1968 12 Sheets-Sheet C FIG. 9.

FIG. 8.

FIG. 7.

Sept. 23, 1969 w. T. GEYER ET AL HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR 12 Sheets-Sheet '7 Filed Nov. 15,

2 @E N 6E v T mwwzwoloo T mwaom L O O u a Sept. 23, 1969 w. T. GEYER ET AL 3,468,300

HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR Filed Nov. 13, 1968 12 Sheets-Sheet a FIG. l6.

Mg M46 FIG.

Sept. 23, 1969 Filed Nov.

W. T. GEYER ET AL HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR FIG.

12 Sheets-Sheet u Lrva FIG. l8.

Sept. 23, 1969 w. T. GEYER ET AL HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR 12 Sheets-Sheet 1-) Filed Nov. 15,

FIG. 2!.

Sept. 23, 1969 w. T. GEYER ET AL 3,468,300

HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR Filed Nov. 13, 1968 1,2 Sheets-Sheet 11 1 l 1 I I FIG. 23. 1 r 1 INVENTORS.

WALLACE T. GEYER EDWARD L. COYLE ATTORNEY Sept. 23, 1969 w. T. GEYER ET AL HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR Filed Nov. 13, 1968 12 Sheets-Shoot 25.

FIG. 25,

EDWARD L. COYLE ATTORNEY United States Patent O 3,468,300 HEAT TRANSFER MEANS FOR A RAILWAY TANK CAR Wallace T. Geyer, Des Peres, and Edward L. Coyle, St.

Charles, Mo., assignors to ACF Industries, Incorporated, New York, N.Y., a corporation of New Jersey Continuation-impart of application Ser. No. 663,342 Aug. 25, 1967. This application Nov. 13, 1968, Ser. No. 777,998

Int. Cl. B61d /04; E01c 19/45 US. Cl. 126-3435 20 Claims ABSTRACT OF THE DISCLOSURE A railway tank car for the transport of lading adapted to be maintained at a predetermined temperature, particularly during transit. A heat transfer pipe mounted on the tank car has an inner end portion extending within the tank shell and an outer end portion extending outwardly of the tank shell. The heat transfer pipe includes a porous wick and a vaporizable or volatile fluid moving between ends of the pipe by a capillary action, the fluid being vaporized along the length of one end portion of the pipe and condensing along the length of the other end portion of the pipe. Means are mounted on the railway car to either heat or cool the outer end portion of the heat pipe for the transfer of heat between the inner and outer end portions to provide a predetermined temperature for the outer end portion. A plurality of spaced parallel plates are mounted about the outer end portion for the transfer of heat therebetween.

CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part application of copending application Ser. No. 663,342 filed Aug. 25, 1967, now abandoned, and entitled Means to Heat Ladings in a Railway Tank Car.

BACKGROUND OF THE INVENTION Heat transfer pipes commonly known as heat pipes comprise an outer enclosed shell, a porous wick, and a working fluid for wetting the wick. A portion of the heat pipe referred to as the boiler section is heated and the working fluid in the boiler area is vaporized and driven from the boiler. As heat is given off by the heat pipe in a condenser section of the heat pipe, the vaporized fluid condenses to a liquid and is returned to the boiler by the capillary action of the wick. Such heat pipes transport thermal energy at efficiencies greater than ninety (90) percent and have an effective thermal conductivity several thousand times that of copper. Also, the heat transfer is up to five hundred (500) times that of a solid thermal conductor of the same cross section.

DESCRIPTION OF THE INVENTION The present invention is directed to a railway tank car having a heat pipe mounted thereon for maintaining lading at a predetermined temperature during transit and at unloading sites. A generally straight length of the heat pipe has an inner end portion mounted within the tank and has an outer end portion extending outwardly of the tank. The outer end portion has a plurality of spaced parallel plates or fins mounted thereon which provide for heat tarnsfer between the plates and outer end por tion. Means on the tank car adjacent the outer end portion provide a predetermined temperature in said outer end portion and may comprise either a refrigeration unit to provide low temperatures or a heat furnace to provide high temperatures. The heat transfer pipe comprises an ice outer enclosed casing, a porous wick positioned adjacent the casing, and a vaporizable fluid within the casing, the fluid being vaporized along the length of the pipe in the end portion having the greater temperature and condensing along the length of pipe in the end portion having the lesser temperature. When a refrigeration unit is provided for cooling the outer end portion of the heat pipe, the working fluid is vaporized along the inner end portion. When a heat furnace is positioned adjacent the outer end portion of the heat pipe to increase the temperature of the outer end portion, the working fluid is condensed along the inner end portion. The fluid moves between the end portions by the capillary action of the wick. Suf ficient working fluid is put into the heat pipe to wet the entire wick and the wick is held tightly and uniformly against the inside wall of the heat pipe.

It is highly desirable to have the heat pipe sloping slightly downwardly from the end portion along which the fluid condenses. An optimum slope is slightly above the maximum grade on railway tracks over which the tank car is transported so that the heat pipe will always have at least a small amount of slope.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the appended claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,

FIGURE 1 is a side elevation of a railway tank car comprising the present invention indicating a heat pipe mounted within the tank with an outer end portion thereof extending outwardly of the tank into a furnace;

FIGURE 2 is an end elevation of the railway tank car lllustrated in FIGURE 1 with certain parts broken away to indicate the furnace and air conduits for the furnace;

FIGURE 3 is a top plan of the furnace mounted on an end of the railway tank car;

FIGURE 4 is a side elevation of the furnace with certam parts broken away to show the interior of the furnace;

FIGURE 5 is a section taken generally along line 55 of FIGURE 4 and indicating the air inlet and air outlet conduits for the furnace;

FIGURE 6 is a longitudinal section taken generally along line 66 of FIGURE 1 and showing the heat pipe mounted within the tank;

FIGURES 7-9 are perspective views indicating the sequence of assembly of the furnace on the end of the railway tank car;

FIGURE 10 is an elevation of a heat pipe with certain parts broken away and in section to indicate the interior of the heat pipe;

FIGURE 11 is a section taken generally along line 11-11 of FIGURE 10;

FIGURE 12 is a diagrammatic view indicating heat removal from the heat pipe within the tank;

FIGURE 13 is a diagrammatic view indicating heat addition to the heat pipe in the furnace area outside the tank;

FIGURE 14 is a perspective of the outer end portions of the heat pipes illustrating the fins connected thereto;

FIGURE 15 is an enlarged cross section of a heat pipe with fins secured thereto;

FIGURE 16 is a section taken generally along line 1616 of FIGURE 15;

FIGURE 17 is a schematic view of a batfle arrangement adjacent the heat pipes to provide circulation be neath the heat pipes to the bottom of the tank;

FIGURE 18 is an enlarged elevation of the baffle arrangement shown in FIG 17;

FIGURE 19 is a schematic view of a modified bafile arrangement to provide circulation adjacent the bottom of the tank;

FIGURE 20 is a perspective of a separate embodiment of a heat producing furnace which may be mounted on a railway tank car to provide heat for the heat pipe;

FIGURE 21 is an end elevation of the embodiment shown in FIGURE 20 and showing vanes for transferring heat from the heat pipe;

FIGURE 22 is a partial section of a modified fin arrangement for the end portion of the heat pipe extending within the furnace;

FIGURE 23 is a section, partly schematic, of an end of a railway tank car illustrating another embodiment of the invention having means for cooling the outer end portion of the heat transfer pipe;

FIGURE 24 is a perspective, certain parts broken away, of the outer end portion of the seat transfer pipe shown in FIGURE 23 illustrating the spaced parallel plates about the outer end portion; and

FIGURE 25 is a schematic of the refrigeration cycle for cooling the outer end portion of the heat transfer pipe for the embodiment shown in FIGURES 23 and 24.

Referring to the drawings for a better understanding of the invention, an insulated railway tank car is generally indicated in FIGURE 1 and comprises an inner tank 12, an outer jacket 14 extending about the circumference of tank 12, and a layer of insulating material 16, such as a polyurethane foam material or fiber glass, between outer jacket 14 and inner tank 12. A center sill 18 extends the length of a railway car 10 and is secured to inner tank 12 with outer jacket 14 being attached to the outer sides of center sill 18. A coupler 19 is mounted within each end of center sill 18. A wheeled truck is provided adjacent each end of railway tank car 10.

Mounted on an end of railway tank car 10 is one embodiment of a heat producing furnace generally indicated 22 and of the open flame type. To supply fuel, such as propane gas, to furnace 22, a fuel container 24 is mounted on each side of railway tank car 10 and has a fuel line 26 leading to furnace 22. Mounted within inner tank 12 for heating liquid lading therein to temperatures of 500 F. or greater are a pair of parallel straight heat pipe sections 28 forming the heat transfer means for transferring heat from furnace 22 to the la-ding within inner tank 12 as will be explained. Each straight heat pipe section 28 includes an inner portion 30 mounted within tank 12 and an outer end portion 32 which extends through the adjacent end of inner tank 12 and outer jacket 14 within furnace 22. As shown in FIGURE 6, brackets generally indicated 34 have sleeves 36 receiving inner heat pipe portions 30 and lower legs secured to the inner surface of tank 12 to support heat pipe sections 28 within the tank at a height above the bottom of the tank. As shown in FIGURE 1, heat pipe sections 28 slope downwardly to outer end portions 32 within furnace 22. As it is desirable for sections 28 to have such a downwardly Slope under all operating conditions, the slope may preferably be between two percent (2%) and four percent (4%) which is normally the maximum railway grade encountered. Thus, the slope of sections 28 under operating conditions may vary from around zero to an eight percent (8%) slops depending on the grade of the railway track.

Referring now to furnace 22 and more particularly to FIGURES 25 and 79, an outer housing 38 has air inlet conduits 40 adjacent its upper end and extends downwardly to a horizontal section 42 beneath center sill 18 as shown in FIGURE 2. Fuel lines 26 from fuel containers or tanks 24 lead to burner nozzles 44 suitably mounted within furnace 22. Positioned above nozzles 44 are a pluraliy of vanes or fins 46 secured about outer end portions 32 of heat pipe sections 28. A hearing 48 supports each outer end portion 32 and is secured between tank 12 and furnace 22 as shown in FIGURE 4. Mounted on the extending end of each end portion 32 outwardly of furnace 4 22 is a pressure relief safety device 50 on each section 28 which is actuated at a predetermined high pressure to prevent overheating of heat pipe section 28. A suitable protective cover 52 is secured to the outer surface of outer housing 38 to house safety devices 50.

Extending upwardly from horizontal section 42 is an inner housing generally indicated 54 and forming an air outlet conduit. Inner housing 54 has an inner liner 56 with an insulating material 58 positioned between iner lier 56 and outer liner 60 of housing 54. An upper cap or cover generally indicated 62 is positioned over the upper end of housing 54 to prevent foreign matter and rain from entering outlet conduit or duct formed by inner housing 54. The exhaust gases pass from outlet openings 64 into the atmosphere. Inner housing 54 is reduced in size by an inwardly sloping intermediate portion 66 which confines the upwardly moving hot gases to provide a suitable draft of air through the furnace and ,to maintain the heat adjacent heat pipe section 28 at a high temperature of around 400 F.-500 F. The air and gas mixture burns below fins 46 and the heat passes upwardly through the spaced fins 46 to heat heat pipe sections 28. Fins 46 are at a temperature of around 700 F.800 F. In order to provide an adequate draft, inner housing 54 should be of a height of around six to eight feet above fins 46.

Referring particularly to FIGURES 14-16, fins 46 are rectangular and around 16 inches by 24 inches. For a length of outer heat pipe portion 32 of around thirtyeight (38) inches, sixty (60) fins may be provided around .2 inch in thickness with .3 inch clearance between adjacent fins 46. Heat pipe sections 38 may be around three and one-half (3 /2) inches in diameter and spaced around five (5) inches from each other.

To secure fins 46, an outer sleeve 70 within inner housing 54 receives outer end portion 32 and has fins 46 welded thereto at 72. Outer sleeve 70 is spaced from heat pipe section 32 by a layer of eutectic 74 formed of a metallic alloy and adapted to melt at around 900 F. Eutectic 74 separates heat pipe section 32 from outer sleeve 70 and acts as an additional safety feature. If furnace 22 supplies more heat than heat pipes 32 can dissipate, the temperature of fins 46 is increased and the eutectic 74 melts and breaks the metal-to-metal contact between sleeve 70 and heat pipes 32 therefore substan tially reducing the rate of heat transfer between fins 46 and heat pipes 32. Eutectic 74 also simplifies manufacture as heat pipes 32 and fins 46 may be built separately and then joined with eutectic.

Referring now to FIGURES 79, the sequence of assembly of furnace 22 is illustrated. First, a support bracket 76 is secured to the upper surface of center sill 18. Then, a preformed inner housing 54 with fins 46 and heat pipes 32 positioned inside is secured to bracket 76. Fins 46 have been previously positioned within inner housing 54 and receive outer end portions 32. Interfitting portions 78 of support bearing 48 permit a suitable connection of inner housing 54 thereto. The outer furnace housing 38 is then positioned over inner housing 54 as shown in FIGURE 9 and suitable safety devices 50 are mounted on the ends of outer end portions 32. Burner nozzles 44 in fuel lines 26 may then be suitably connected to the lower portion of furnace 22.

Referring to the heat pipe formed by heat pipe sections 28 and more particularly to FIGURES l0l3, each section 28 is of a straight length without any bends therein in order to obtain best results. Each section 28 is around three and one-half (3 /2) inches in diameter and comprises a closed outer shell 80 formed of stainless steel, a porous wick 82 formed of a small mesh stainless steel screen wire of around three hundred (300) openings per inch and a working fluid 84 of water. Outer end portion 32 is referred to as the boiler section while portion 30 within the tank is referred to as the condenser section as shown in FIGURE 10. Heat pipe section 28 comprises a boilingcondensing system which uses capillary action to return the condensate. When heat is added in the boiler section or outer end portion 32 by furnace 22 and removed in the condenser section by the lading contacting outer shell 80, vapor is driven from outer end portion 32 to inner portion 30. The porous wick 82 pumps the condensate back to the boiler section by capillary action. In outer end portion 32 or the boiler section, the radius of curvature of the meniscus indicated at 86 decreases during start-up, becoming more concave due to evaporation as illustrated schematically in FIGURE 13. In inner pipe portion 30 or the condenser section, the radius of curvature of meniscus 86 increases, becoming less concave and approaching a relatively flat surface as illustrated in FIG- URE 12. Thus, a pressure gradient is provided in the working fluid 84 which drives it from the inner pipe portion 30 to the outer end portion 32 as working fluid 84 condenses. A generally void space 87 is provided adjacent wick 82 and is normally filled with the vapor of working fluid 84 during operation of heat pipe section 28. The heat transferred by heat pipe section 28 is primarily due to the latent heat of vaporization of the working fluid 84 which is absorbed by the boiler section and given up in the condenser section. The boiling and condensing processes are generally independent and either process may take place over a large area. For further details concerning heat pipe section 28, reference is made to Patent No. 3,229,759 dated I an. 18, 1966 and entitled Evaporation- Condensation Heat Transfer Device, the entire disclosure of which is incorporated by this reference.

The slope in heat pipe sections 28 spaces the extending ends of portions 30 a substantial distance from the bottom of the tank. To provide adequate circulation of the lading, deflector or baffle plates 88 are mounted along each side of heat pipe portions 30 as shown particuarly in FIGURES 17 and 18 to direct the lading beneath heat pipe portions 30. Straps 90 may be secured between deflector plates 88 to support heat pipe sections 28 and support brackets 92 are secured between deflector plates 88 and the inner surface of tank 12.

FIGURE 19 shows a modified arrangement in which heat pipe sections 28A are positioned along a side of tank 12A. A baffle 94 is mounted adjacent heat pipe section 28A by supports 96 and directs lading beneath heat pipe section 28A for effective circulation of the lading as shown in FIGURE 19. A suitable support 98 may be provided to support heat pipe sections 28A.

Heat may be transferred to the heat pipe by radiation, conduction, or convection. Referring to FIGURES 20 and 21, an embodiment of a radiaant type heat source is illustrated and employs a gas fired infrared energy generator. Heat pipe section 28B has a plurality of radially extending fins 100 secured thereto and perpendicularly extending fins 101 adjacent the ends of fins 100. Four bands each including four radiant heaters 102 are mounted adjacent the free ends of fins 100. Each radiant heater 102 includes an enclosed housing and may be of the type commercially available. Each heater 102 is preheated to a temperature of around 250 F. by an open flame or electrically. Propane gas is supplied to each heater 102 by a fuel inlet 104 for each heater. Suitable thermos-tats 106 are provided to control the temperature of heaters 102. Air is supplied between the free ends of fins 100 and radiant heaters 102 for oxidation of the gas.

Referring to FIGURE 22, a modified fin arrangement for the extending end portion of the heat pipe is illustrated, fins 46A of around .2 inch thickness are spaced around one inch from each other with the space filled with ceramic particles 108 around one-half /2) inch in diameter. Ceramic particles which have been found to be effective as berl saddles and Raschig rings having a maximum dimension of around one-half /2) inch. The ceramic particles 108 remove additional heat from the combustion gases and provide a more uniform heat input to heat pipe 28 since heat is stored by the ceramic particles and provide an increased thermal efiiciency.

Referring to FIGURES 23-25, a modified embodiment of this invention is illustrated in which means are provided adjacent the outer end portion of the heat transfer pipe to cool the outer end portion for removing heat from the lading and the interior of the tank shell. Heat transfer pipe 28C includes inner end portion 300 and outer end portion 320. Inner end portion 30C extends within tank shell 12C and a bearing 48C receiving outer end portion 32C is secured between tank shell 12C and an evaporator unit generally indicated 112.

As shown particularly in FIGURE 24, evaporator unit 112 includes outer side walls 114 connected by respective upper and lower walls 116 and 118. End walls 120 form the ends of evaporator unit 112. Perforated intermediate walls 122 and 124 form upper and lower chambers 126 and 128 with respective walls 116 and 118. Upper chamber 126 forms a vapor plenum chamber and lower chamber 128 forms a liquid plenum chamber. Spaced between end walls 120 and extending between intermediate plates 122 and 124 are heat transfer fins or plates 130. Outer end portion 32C is received within central openings in heat transfer plates 130 and is secured to plates 130. Evaporator unit 112 is suitably enclosed by a layer of insulation 131, such as polyurethane foam material.

Liquid refrigerant enters liquid plenum chamber 128 from a liquid inlet line 132 and absorbs heat from fins 130. Upon the absorption of heat from fins 130, the liquid refrigerant is converted to vapor and passes through apertures in wall 124. Vapor plenum chamber 126 reoeives vapor through apertures in plate 122 and vaporized refrigerant is discharged from chamber 126 through vapor discharge line 134.

Heat is transferred from the lading to outer end portion 32C where the heat is absorbed by fins 130 and the working fluid within heat pipe 28C is condensed. Thus, outer end portion 32C forms the condenser portion of heat pipe 28C and inner end portion 30C forms the boiler portion where the lading is cooled by contact with inner end portion 300, and the Working fluid within inner end portion 30C is vaporized. The internal construction of heat pipe 28C is similar to the construction of heat pipe 28 with the boiler and condenser end portions reversed from that illustrated for heat pipe 28 in FIGURES 1-16. As water would tend to freeze at low temperatures, the working fluid employed for heat pipe 280 is ethylene glycol and the lading may be cooled to temperatures as low as around minus eighty degrees Fahrenheit (80 F.).

Referring particularly to FIGURE 25, a conventional refrigeration cycle is employed with a refrigerant liquid absorbing heat from fins 130 as indicated above and forming a vapor or gas. A compressor 136 compresses the refrigerant gas from evaporator 112 and discharges the gas through line 138 to condenser 140. Condenser 140 includes a fan for cooling the gas and the refrigerant changes from gas to liquid. The liquid refrigerant is then collected in receiver 142 and is forced by pressure to an expansion valve 144 in line 132 leading to evaporator 112. Expansion valve 144 controls the flow of liquid refrigerant to evaporator 112 and is responsive to the outlet temperature of evaporator 112. Expansion valve 144 releases the pressure of the liquid refrigerant and reduces it from the condenser pressure to that of the evaporator. This reduction of pressure allows the refrigerant to boil at a lower temperature upon the flow of heat from fins 130 into the liquid refrigerant within chamber 128.

Housing 146 encloses the refrigerant units except for evaporator 112. To supply power for the operation of the refrigeration cycle, a diesel engine 148 drives a generator 150. Electrical energy from generator 150 drives a compressor motor and a condenser fan motor.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results obtained.

What is claimed is:

1. A railway tank car adapted to provide a predetermined temperature in lading carried by the tank car and comprising, a tank shell having ends to form an enclosure for carrying lading, a heat transfer pipe mounted on the tank car having an inner end portion extending within the tank shell and an outer end portion extending outwardly of the tank shell, means mounted on said railway car adjacent the outer end portion of said heat transfer pipe to provide a temperature in said outer end portion different from the temperature in said inner end portion within the tank shell, said heat transfer pipe comprising an outer enclosed casing, a wick positioned within the casing and extending continuously between the outer end portion and the inner end portion, and a vaporizable fluid within the casing moving between the outer end portion and the inner end portion by a capillary action, the fluid being vaporized along the length of the pipe in the end portion having the greater temperature and condensing along the length of the pipe in the end portion having the lesser temperature.

2. A railway tank car as set forth in claim 1 wherein said means mounted on said railway car adjacent the outer end portion of said heat transfer pipe comprises heat producing means to raise the temperature of the outer end portion for the transfer of heat from said outer end portion to said inner end portion of the heat pipe within the tank shell.

3. A railway tank car as set forth in claim 1 wherein said means mounted on said railway car adjacent the outer end portion of said heat transfer pipe comprises means to lower the temperature of said outer end portion for the transfer of heat from said inner end portion within the tank shell to said outer end portion,

4. A railway tank car adapted to provide a predetermined temperature in lading carried by the tank car and comprising, a tank shell, a heat transfer pipe mounted on the tank car having an inner end portion extending within the tank shell and an outer end portion extending out wardly of the tank shell, a plurality of fins about the outer end portion of said heat transfer pipe adapted to provide a heat transfer between the fins and outer end portion, means mounted on said railway car adjacent the fins to provide a temperature in said outer end portion different from the temperature in said inner end portion, said heat transfer pipe comprising an outer casing, a wick positioned within the casing and extending continuously between the outer end porton and the inner end portion, and a vaporizable fluid within the casing moving between the outer end portion and the inner end portion by a capillary action, the fluid being vaporized along the length of the pipe in the end portion having the greater temperature and condensing along the length of the pipe in the end portion having the lesser temperature.

5. A railway tank car as set forth in claim 4 wherein said means mounted on said railway car adjacent the outer end portion of said heat transfer pipe comprises heat producing means to raise the temperature of said outer end portion for the transfer of heat from said outer end portion to said inner end portion of the heat pipe Within the tank shell.

6. A railway tank car as set forth in claim 4 wherein said means mounted on said railway car adjacent the outer end portion of said heat transfer pipe comprises means to lower the temperature of the said outer end portion for the transfer of heat from said inner end portion within the tank shell to said outer end portion.

7. A railway tank car for the transport of lading adapted to be maintained at a predetermined temperature during transit and comprising, a tank shell for carrying lading and having ends to form an enclosure, a heat transfer pipe mounted within said shell, one end of said pipe having an outer end portion extending outwardly of an end of said tank shell, and heat producing means outwardly of said shell to heat said heat transfer pipe for the transfer of heat therefrom to the lading within the shell, said heat transfer pipe comprising an outer casing, a porous wick adjacent the inner circumferential surface of the casing, and a vaporizable fluid within the casing, said fluid being'vaporized from the heat generated by said heat producing means and moving outwardly away from said heat producing means, said vaporized fluid condensing along the length of the heat transfer pipe and returning toward said heat producing means by a capillary action of said wick, said heat producing means being mounted on an end of said railway car adjacent the end of said shell and comprising a furnace, an air inlet conduit to supply air to said furnace, and an outlet conduit extending generally vertically upwardly from said furnace, said outer end portion of said pipe extending within said furnace and having a plurality of thin metal plates extending outwardly therefrom to conduct heat from said furnace to said heat transferpipe.

8. A railway tank car as set forth in claim 7 wherein said furnace is of the open flame type and includes a plurality of nozzles, and means to supply a combustible fuel to said nozzles.

9. A railway tank car as set forth in claim 7 wherein said furnace includes a radiant heater, and said metal plates extend in a direction parallel to the longitudinal axis of said heat pipe between the heat pipe and the radiant heater for radiating heat to the heat pipe.

10. A railway tank car for the transport of lading adapted to be maintained at a predetermined temperature and comprising, a tank shell having ends to form an enclosure for carrying lading, a center sill secured to the tank shell, a heat transfer pipe mounted within said shell, one end of said pipe having an outer end portion extending outwardly of an end of said tank shell, and heat producing means mounted on said railway tank car outwardly of said shell to heat said outer end portion for the transfer of heat therefrom to the portion of the pipe within the shell and a subsequent transfer of heat to the lading within the shell, said heat transfer pipe comprising an outer enclosed casing, a porous wick positioned adjacent the inner circumferential surface of the casing, and a vaporizable fluid within the casing, said fluid being vaporized from the heat generated by said heat producing means and moving outwardly away from said heat producing means, said vaporized fluid condensing along the length of the heat transfer pipe and returning toward said heat producing means by a capillary action of said wick, said heat producing means comprising a furnace mounted on an end of the railway car, an outlet conduit extending generally vertically upwardly from said furnace to remove exhaust gases, and an air inlet conduit to supply air to said furnace comprising a generally downwardly extending vertical portion and an integral generally horizontal portion extending therefrom beneath the center sill to the furnace thereby to provide air to the furnace at a position generally adjacent the center sill.

11. A railway tank car for the transport of lading adapted to be heated to a predetermined temperature and comprising, a tank shell having ends to form an enclosure for carrying lading, a heat transfer pipe mounted within said tank shell, one end of said pipe having an outer end portion extending outwardly of an end of said tank shell, and heat producing means mounted on said railway tank car outwardly of said tank shell to heat said outer end portion for the transfer of heat therefrom to the portion of the pipe within the shell and a subsequent transfer of heat to the lading within the shell, said heat transfer pipe comprising an outer enclosed casing, a porous wick positioned adjacent the inner circumferential surface of the casing, and a vaporizable fluid within the casing, said fluid being vaporized from the heat generated by said heat producing means and moving outwardly away from said heat producing means, said vaporized fluid condensing along the length of the heat transfer pipe within said tank shell and returning toward said heat producing means by a capillary action of said wick.

12. A railway tank car adapted to maintain lading at a predetermined temperature during transit and comprising, a tank shell having ends to form an enclosure for carrying lading, a heat transfer pipe having an inner end portion mounted within said shell and an outer end portion extending outwardly of said tank shell, and heat producing means to heat said outer end portion of said pipe being mounted on said railway car adjacent an end of said shell and comprising a furnace, an air inlet conduit to supply air to said furnace, and an outlet conduit extending generally vertically upwardly from said furnace, said outer end portion of said heat transfer pipe extending within said furnace to conduct heat from said furnace, said heat transfer pipe being of a continuous generally straight length and comp-rising an outer generally cylindrical enclosed casing, a porous generally annular wick positioned adjacent the inner circumferential surface of the casing for substantially the entire length of the casing, and a vaporizable fluid within the casing, said fluid being vaporized from the heat generated by said heat producing means and flowing outwardly away from said heat producing means, said vaporized fluid condensing along the length of the inner end portion of the heat transfer pipe within the tank shell and returning toward said heat producing means by the capillary action of said wick.

13. A railway tank car for the transport of lading adapted to be maintained at a predetermined temperature and comprising, a tank shell having ends to form an enclosure for carrying lading, a heat transfer pipe having an inner end portion mounted within said shell and an outer end portion extending outwardly of said tank shell, and heat producing means mounted on said railway tank car outwardly of said shell to heat said outer end portion for the transfer of heat therefrom to the inner end portion of the pipe within the shell and a subsequent transfer of heat to the lading within the shell, said heat transfer pipe comprising an outer enclosed casing, a porous wick positioned adjacent the inner circumferential surface of the casing, and a vaporisable fluid within the casing, said fluid being vaporized from the heat generated by said heat producing means and moving outwardly away from said heat producing means, said vaporized fluid condensing along the length of the inner end portion of the heat transfer pipe within the tank shell and returning toward said heat producing means by a capillary action of said wick, said heat producing means comprising a furnace mounted on an end of the railway car, an air inlet conduit to supply air to said furnace, and an outlet conduit extending generally vertically upwardly from said furnace to remove exhaust gases.

14. A railway tank car as set forth in claim 13 wherein the longitudinal axis of said pipe slopes upwardly from said furnace at least around three degrees with respect to the longitudinal axis of said tank shell, and baflies are positioned within the tank shell adjacent said heat transfer pipe to provide adequate circulation of lading to the bottom of the tank shell.

15. A railway tank car as set forth in claim 13 wherein a sleeve within said furnace receives the outer end portion of said heat transfer pipe in annular spaced relation thereto, a plurality of spaced parallel fins are secured to the outer surface of said sleeve and extend therefrom, and a layer of eutectic in the innular space between the sleeve and outer end portion secures said sleeve to said outer end portion whereby said eutectic melts at a predetermined high temperature to space the sleeve from said outer end portion.

16. A railway tank car as set forth in claim 13 wherein said heat transfer pipe comprises a pair of spaced, parallel heat pipe sections each being of a straight continuous length, said heat pipe sections being separate and not connected to each other.

17. A railway tank car as set forth in claim 13 wherein said outer end portion of said pipe extending within said furnace has a plurality of thin metal plates extending outwardly therefrom in a direction generally perpendicularly to the horizontal axis of the pipe, and ceramic particulate material is positioned between the thin metal plates to increase the thermal efliciency of said furnace.

18. A railway tank car adapted to provide a predetermined temperature in lading carried by the tank car and comprising, a tank shell having ends to form an enclosure for carrying lading, a heat transfer pipe mounted on the tank car having an inner end portion extending Within the tank shell and an outer portion extendig outwardly of the tank shell, means mounted on said railway car adjacent the outer end portion of said heat transfer pipe to cool said outer end portion for removing heat from the inner end portion and the interior of the tank shell, said heat transfer pipe comprising an outer enclosed casing, a wick positioned within the casing and extending continuously between the outer end portion and the inner end portion, and a vaporizable fluid within the casing moving between the outer end portion and the inner end portion by a capillary action, the fluid being vaporized Within the tank shell along the length of the inner end portion of the heat pipe and condensing along the length of the outer end portion of the heat pipe.

19. A railway tank car as set forth in claim 18 wherein said heat pipe is positioned adjacent the upper portion of said tank shell and slopes downwardly from the outer end portion to the inner end portion at least around three degrees with respect to the longitudinal axis of the tank shell.

20. A railway tank car adapted to provide a predetermined temperature in lading carried by the tank car and comprising, a tank shell having ends to form an enclosure for carrying lading, a heat transfer pipe mounted on the tank car having an inner end portion extending within the tank shell and an outer end portion extending outwardly of the tank shell, an evaporator mounted on the tank car receiving the outer end portion of the heat pipe, a plurality of spaced fins on the outer end portion to transfer heat from the outer end portion, a refrigerant for said evaporator absorbing heat from the fins to cool said outer end portion for removing heat from the inner end portion and the interior of the tank shell, said heat transfer pipe comprising an outer casing, a wick positioned within the casing and extending continuously between the outer end portion and the inner end portion, and a vaporizable fluid within the casing moving between the outer end portion and the inner end portion by a capillary action, the fluid being vaporized within the tank shell along the length of the inner end portion of the heat pipe and condensing the length of the outer end portion of the heat pipe.

References Cited UNITED STATES PATENTS 2,820,451 1/1958 Brock et al. 3,143,108 8/1964 Rogers. 3,229,759 1/1966 Grover l65l05 3,372,693 3/1968 Gutzeit.

CHARLES J. MYHRE, Primary Examiner US. Cl. X.R. -105

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