US3907028A

US3907028A - Concentric cylinder heat exchanger

Info

Publication number: US3907028A
Application number: US466351A
Authority: US
Inventors: Drew B Lawson
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1974-05-02
Filing date: 1974-05-02
Publication date: 1975-09-23
Anticipated expiration: 1992-09-23

Abstract

A heat exchanger formed by a plurality of concentric tubes having annular spaces therebetween. Helical-shaped vanes having waves therein are disposed in the annular spaces. Interconnection means are provided to create fluidic paths through the annular spaces.

Description

United States Patent 1 Lawson [451 Sept. 23, 1975 CONCENTRIC CYLINDER HEAT EXCHANGER [75] Inventor: Drew B. Lawson, Los Gatos, Calif.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

[22] Filed: May 2, 1974 [21] Appl. No.: 466,351

{52] US. Cl. 165/156; 165/141; 138/38 [51] Int. Cl. F28D 7/00 [58] Field of Search 165/140, 141, 156;

[56] References Cited UNITED STATES PATENTS 2,300.57) 11/1942 Lenning 138/38 X Carter 165/156 X Pearson 138/38 Primary ExaminerCharles J. Myhre Assistant E.\'aminerTheophil W. Streule, Jr. Attorney, Agent, or Firrr'1Rich1ard S. Sciascia; .I. M. St. Amand; D'arrell E. Hollis [57] ABSTRACT A heat exchanger formed by a plurality of concentric tubes having annular spaces therebetween. Helicalshaped vanes having waves therein are disposed in the annular spaces. Interconnection means are provided to create fluidic paths through the annular spaces.

3 Claims, 5 Drawing Figures I; ICONCENTRIC CYLINDER HEAT EXCHANGEIR STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufac tured and used by or for the Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

BACKGROUND OFTHE INVENTION 1. Field of the Invention- The presentinvention relates generally to heat exchangers and more particularly to concentric tube heat exchangers having waved, helical-shaped vanes.

2. Description ofthe Prior Art.

A heat exchanger is a device that transfers heat from one fluid to another fluid..Large surface areas between fluids,- turbulence in the fluids, and fluids flowing in opposite directions enhance heat transfer.

There are a wide variety of heat exchangers in the prior art utilizing one or more helical paths. However, such prior art heat exchangers are designed for quick disassembly or easy cleaning with heat transfer being a secondary consideration. Hence, such prior art heat exchangers do not maximize the surface areas between fluids, nor cause fluids to flow in Opposite directions or create turbulence in the fluids.

SUMMARY OF THE INVENTION The general purposes of the present invention are to provide a concentric tube heat exchanger that maximizes the surface area between fluids, causes fluids in adjacent annular spaces to flow in opposite directions, and creates turbulence in the fluids. To attain this, the present invention provides a plurality of concentric cylinders having annular spaces therebetween. Waved, helical-shaped vanes are disposed in the annular spacespManifolds at both ends of the concentric cylinders contain the required flow passages necessary to create opposite fluid flow in adjacent annular spaces.

Accordingly, one object of the present invention is to provide fluid flow in adjacent fluid flow paths in opposite directions. I

Another object of the present invention is to induce turbulence in the field in all fluid flow paths.

Another object of the present invention is to maximize the surface area between adjacent fluid flow paths.

Another object of the present invention is to maximize heat exchange properties.

Another object of the present invention is to maximize the efficiency of heat exchange.

Another object of the present invention is to-provide improved and easier maintenance.

Another object of the present invention is to provide economy of fabrication and operation.

Othef objects and a more complete appreciation of the present invention and itsmany attendant advantages will become apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein like reference numerals refer to like parts throughout the figures thereof and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a specific embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a heat exchanger 10 having a cylindrical casing 12 and a series of concentric cylinders 14, I6,

l8

20 and 22 enclosed therein. Annular space 24 is formed between cylindrical casing 12 and concentric cylinder 14.

Annular spaces

26, 28, 30 and 32 are formed between concentric cylinders l4 and l6, l6 and 18, 18 and 20, and 20 and 22, respectively. Annu lar space 34 is the innermost annular space and is formed by concentric cylinder 22. Annular space 24 is the outermost annular space. I

Manifolds 36 and 38 are connected to opposite ends of heat exchanger 10. Manifolds 36 and 38 provide in terconnections between

annular spaces

24, 26, 28, 30, 32 and 34 so .thatfluid paths 40 and 42- are'defined. Note that fluid-path 40 is adjacent to and in an opposite direction from fluid path 42'. Fluid path 40 begins at inlet 44 in manifold 36 and terminatesat outlet 46 in" manifold 38. Fluid path 42 begins at inlet 48 in manifold 38 and terminates at outlet 50 in manifold 36.

Note that adjacent annular spaces have fluids flowing in opposite' directions,"as indicated by arrows 52, 54,

56, 58, 60 and 62. As will be discussed supra, manifolds

j

36 and 38 connectevery other annular space in series to define fluidic'paths 40 and 42.

Now turning to FIG;'2,

fluid paths

40 and 42 are illustrated. F165 2 is a'sectional view along lines 2-2 of FIG. 1.

FIG. 3 is a sectional view along lines 3 of FIG.

1 illustrating manifold 36. Fluid in fluid path 40 enters manifold 36 at inlet 44 and passes into annular space 24 through opening 72. The fluid then passes down annular sp'ace 24 through manifoild 38Iof FIG. I and back down annular space 28. The-flluidjthen passes through opening 74 and .76 in manifold 36 and into annular spaces 32. The fluid then passes down annular space 32 throughmanifold 38 and =outlet 46 of FIG. 1. g

The fluid in fluid path 42 enters manifold 38 at inlet 48 of FIG. I. The fluid flows down annular space 26, enters manifold 36 at opening 78, and exits manifold 36 at opening. 80 into .annularspace 30. The fluid then passesdown annularspace 30 through manifold 38 and back down annularspace 34. The fluid then exits manifold 3a through outlet 50.

Manifold38 is constructed with the requisite opcnings in like manner to manifold 36. Also, additional concentric cylinders over the number shown in FIGS. 1, 2 and 3 may be utilized. Of course, larger manifolds with additional openings will be required in order to correctly define the proper fluid paths.

Now turning to FIG. 4, helical-shaped vane 70, having wave-shaped surfaces, and helical-shaped vane 72 are illustrated. Wave-surfaced, helical-shaped vane is disposed in annular space 28 between concentric cylinders l6 and 18. Helical-shaped vane 72 is disposed in annular space 30 between

concentric cylinders

18 and 20.

Looking along the longitudinal axis of heat exchanger in the direction indicated by arrow 80 in FIG. 4, vane 72 in annular space 30 proceeds in a clockwise direction, as noted by arrow 82, while vane 70 in adjacent annular space 28 proceeds in a counterclockwise direction, as noted by arrow 84. Placing the helical-shaped vanes in such manner creates a cross flow between the fluids in adjacent annular spaces. Arrow 100 indicates the direction of flow of fluid in annular space 30. Arrow 102 indicates the direction of flow of fluid in annular space 28.

The helical-shaped vanes create a large surface area over which fluids in adjacent annular spaces flow, thus increasing the efficiency of heat transfer between the fluids in adjacent annular spaces. In addition, the wavesurfaced, helical-shaped vanes 70 impart turbulence to the fluid in annular space 28, thereby increasing the efficiency of heat transfer between the fluids in adjacent annular spaces to an even greater extent.

It is noted that wave-surfaced, helical-shaped vanes are disposed in

annular spaces

24, 26, 28, 30 and 32 of FIGS. 1, 2 and 3 to simplify the drawings. Wavesurfaced, helical-shaped vane 70 in annular space 28 forms a fluid-tight seal at its top edge 90 with concentric cylinder 16 and its bottom edge 92 with concentric cylinder 18. Of course, in like manner, all helicalshaped vanes in heat exchanger 10 are so sealed to their respective concentric cylinders.

Nowturning to FIG. 5, wave-surfaced, helical-shaped

vanes

74 and 76 in

annular spaces

30 and 28, respectively, proceed in a clockwise direction, as noted by

arrows

96 and 98, when looking along the longitudinal axis of heat exchanger 10 in the direction indicated by arrow 94. Placing the helical-shaped vanes in such manner creates a counter flow or opposite flow be tween the fluids in adjacent annular spaces. Arrow 104 indicates the direction of fluid flow in annular space 30 while arrow 106 indicates the direction of fluid flow in annular space 28.

It is noted that the clockwise, counter-clockwise placements of helical-shaped

vanes

70, 72, 74 and 76 illustrate methods of placement in

annular spaces

24, 26, 28, 30, 32 and 34 of FIGS. 1, 2 and 3 of helicalshaped vanes to achieve various directions of flow between fluids in the adjacent annular spaces. Wavesurfaced, helical-shaped

vanes

74 and 76 are sealed at their edges to the concentric cylinders, forming the annular space in which they are disposed in like manner to vanes 70 and 72 of FIG. 4.

It will be appreciated by those skilled in the art that the specific embodiment of FIG. 1 includes such suitable and necessary fluidic sealing means as to render the specific embodiment operable. Such fluidic sealing means are not illustrated in FIGS. 1, 2, 3, 4 or 5.

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 herein.

I claim:

1. A concentric tube heat exchanger for transferring heat from one fluid to another fluid comprising:

a. a cylindrical casing having a first and a second end;

b. a plurality of concentric cylinders located inside said cylindrical casing, each pair of adjacent concentric cylinders having an annular space therebetween, each said cylinder having a first and a second end;

c. a plurality of helical-shaped vanes having continuously wave shaped surfaces contacting said fluid flowing thereby connected between adjacent concentric cylinders with one vane being disposed in each said annular space, each said vane being attached to each of its respective concentric cylinders along its entire length, said attachments providing fluid-tight seals with said concentric cylinders, said wave shaped surfaces of said helical vanes imparting turbulence to heat exchange fluids flowing through said annular spaces;

d. first inlet means;

e. first outlet means;

f. second inlet means;

g. second outlet means;

h. first and second manifold means connected to the first and second ends, respectively, of said cylindrical casing and to said plurality of concentric cylinders for creating a first and a second fluidic path through said annular spaces, said first fluidic path being between said first inlet means and said first outlet means, said second fluidic path being between said second inlet means and said second outlet means, said first fluidic path being formed by connecting every other annular space in series, starting from the annular space adjacent to the outermost annular space and proceeding to the innermost annular space, said second fluidic path being formed by connecting every other annular space in series, starting from the outermost annular space and proceeding to the annular space adjacent the innermost annular space.

2. The concentric tube heat exchanger of claim 1 wherein said plurality of helical-shaped vanes are disposed eounter-clockwise in the annular spaces of both said first and second fluidic paths, thereby creating counter-flow of fluids in adjacent annular spaces.

3. The concentric tube heat exchanger of claim 1' wherein said plurality of helical-shaped vanes are disposed counterclockwise in the annular spaces defining said first fluidic path and clockwise in the annular spaces defining said second fluidic path, thereby creating cross counter-flow of fluids in adjacent annular spaces.

l i I i

Claims

1. A concentric tube heat exchanger for transferring heat from one fluid to another fluid comprising: a. a cylindrical casing having a first and a second end; b. a plurality of concentric cylinders located inside said cylindrical casing, each pair of adjacent concentric cylinders having an annular space therebetween, each said cylinder having a first and a second end; c. a plurality of helical-shaped vanes having continuously wave shaped surfaces contacting said fluid flowing thereby connected between adjacent concentric cylinders with one vane being disposed in each said annular space, each said vane being attached to each of its respective concentric cylinders along its entire length, said attachments providing fluid-tight seals with said concentric cylinders, said wave shaped surfaces of said helical vanes imparting turbulence to heat exchange fluids flowing through said annular spaces; d. first inlet means; e. first outlet means; f. second inlet means; g. second outlet means; h. first and second manifold means connected to the first and second ends, respectively, of said cylindrical casing and to said plurality of concentric cylinders for creating a first and a second fluidic path through said annular spaces, said first fluidic path being between said first inlet means and said first outlet means, said second fluidic path being between said second inlet means and said second outlet means, said first fluidic path being formed by connecting every other annular space in series, starting from the annular space adjacent to the outermost annular space and proceeding to the innermost annular space, said sEcond fluidic path being formed by connecting every other annular space in series, starting from the outermost annular space and proceeding to the annular space adjacent the innermost annular space.

2. The concentric tube heat exchanger of claim 1 wherein said plurality of helical-shaped vanes are disposed counter-clockwise in the annular spaces of both said first and second fluidic paths, thereby creating counter-flow of fluids in adjacent annular spaces.

3. The concentric tube heat exchanger of claim 1 wherein said plurality of helical-shaped vanes are disposed counterclockwise in the annular spaces defining said first fluidic path and clockwise in the annular spaces defining said second fluidic path, thereby creating cross counter-flow of fluids in adjacent annular spaces.