US3889745A

US3889745A - Heat exchanger and method of making same

Info

Publication number: US3889745A
Application number: US426320A
Authority: US
Inventors: Frederik A Siemonsen
Original assignee: Reynolds Metals Co
Current assignee: Reynolds Metals Co
Priority date: 1973-12-19
Filing date: 1973-12-19
Publication date: 1975-06-17
Anticipated expiration: 1992-06-17

Abstract

A heat exchanger and method of making same is provided and such heat exchanger comprises a plurality of tubes arranged in parallel relation and a plurality of planar fins each having integral tubular collars extending therefrom which engage and are supported concentrically around the tubes with the collars extending from each planar fin being defined by a first set of collars extending in one direction and a second set of collars extending in a direction opposite from the one direction. The fins are fixed against the tubes in substantially parallel relation with the first set of collars of one fin adjoining and cooperating with the second set of collars of an immediately adjacent fin to provide a precise spacing between fins along the tubes.

Description

United States Patent [191 Siemonsen HEAT EXCHANGER AND METHOD OF MAKING SAME [75] Inventor: Frederik A. Siemonsen, Richmond,

[73] Assignee: Reynolds Metals Company,

Richmond, Va.

22 Filed: Dec. 19, 1973 21 Appl. No.: 426,320

[52] US. Cl. l65/15l;--165/l76; 165/182 [51] Int. Cl. F28f l/22 [58] Field of Search 165/151, 182,176, 175,

[56] References Cited UNITED STATES PATENTS 1,521,880 1/1925 Guarino 165/151 1,834,070 12/1931 Parkinson 165/175 1,898,713 2/1933 Carrier et a1. 165/151 2,994,123 8/1961 Kritzer 165/151 3,256,593 6/1966 Whitney 1 29/1573 A 3,468,009 9/1969 Clausing 29/1573 B 3,507,026 4/1970 Collins 29/1573 B 1 June 17, 1975 3,631,922 1/1972 Ponziani 165/1 51 FOREIGN PATENTS OR APPLICATIONS 460,063 l/1937 United Kingdom 165/151 1,104,979 4/1961 Germany 165/182 Primary Examiner-Manuel A. Antonakas Assistant Examiner-James D. Liles [57] ABSTRACT A heat exchanger and method of making same is provided and such heat exchanger comprises a plurality of tubes arranged in parallel relation and a plurality of planar fins each having integral tubular collars extending therefrom which engage and are supported concentrically around the tubes with the collars extending from each planar fin being defined by a first set of collars extending in one direction and a second set'of collars extending in a direction opposite from the one direction. The fins are fixed against the tubes in substantially parallel relationwith the first set of collars of one fin adjoining and cooperating with the second set of collars of an immediately adjacent fin to provide a precise spacing between fins along the tubes.

' 6 Claims, 4 Drawing Figures HEAT EXCHANGER AND METHOD OF MAKING SAME BACKGROUND OF THE INVENTION Tube and fin type heat exchangers are in common use throughout industry and in general it is preferred that the fins therefor be made of comparatively hard metallic materials making such fins less susceptible to damage yet without impairing their heat transfer capabilities. However, it has been found that with fins made of high temper aluminum alloys, such as H-l9 temper, that any tendency to form integral collars above a certain height in such fins results in frequent cracking of collars whereby the fin is generally unsatisfactory for use in a heat exchanger.

It has also been found that with H-l9 aluminum alloys ranging in thickness from 0.010 inch to 0.002 inch it is not commercially practical to make integral tubular collars therein for fin-stacking purposes with such collars being of substantial height, generally in excess of 1/1 6 inch, for example, whereby it is necessary to resort to dead soft or partial tempered metal which increases cost substantially.

SUMMARY This invention provides an improved tube and fin type heat exchanger, and method of making same, wherein the fins may be made of H-l9 temper aluminous materials having a thickness ranging from 0.010 inch to 0.002 inch and such heat exchanger may be provided with double the spacing distance between immediately adjacent fins than was possible heretofore yet at a comparatively small cost. The heat exchanger comprises a plurality of tubes arranged in parallel relation and a plurality of planar fins each having integral tubular collars extending therefrom which engage and are supported concentrically around said tubes with the collars extending from each planar fin being defined by a first set of collars extending in one direction and a second set of collars extending in a direction opposite from said one direction. The fins are fixed against said tubes in substantially parallel relation with the first set of collars of one fin adjoining and cooperating with the second set of collars of an immediately adjacent fin to provide said double spacing distance between fins along the tubes in a precise manner.

Other details, uses, and advantages of this invention will be readily apparent from the exemplary embodiment thereof presented in the following specification, claims, and drawing.

BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing shows present preferred embodiments of this invention, in which FIG. 1 is a side elevation illustrating one exemplary embodiment of the heat exchanger of this invention;

FIG. 2 is a perspective view of a typical fin comprising the heat exchanger of FIG. I particularly illustrating integral collars defined therein and with such fin being drawn with an exaggerated thickness;

FIG. 3 is a fragmentary view drawn to an enlarged scale with parts in cross section and parts broken away particularly illustrating the manner in which the fins of the heat exchanger of FIG. 1 are stacked in position with respect to their associated tubes, and

FIG. 4 is an enlarged fragmentary cross-sectional view taken essentially on line 44 of FIG. 3.

DESCRIPTION OF ILLUSTRATED EMBODIMENT Reference is now made to FIG, 1 which illustrates one exemplary embodiment of the heat exchanger of this invention which is designated generally by the reference numeral 10 and comprises a pair of oppositely arranged header assemblies shown as a top assembly 11 and a bottom assembly 12. The heat exchanger 10 also has a plurality of tubes 13 arranged in parallel relation between the header assemblies 11 and 12 and a return conduit 14 which will be described in more detail subsequently. The heat exchanger 10 of this example has a temperature control valve 15 which may be of any suitable known construction and the valve 15 is particularly adapted to receive a fluid such as a liquid through a suitable inlet 16 thereof and if the liquid needs to be cooled it is diverted by the valve 15 into the header assembly I l and flows through the tubes 13 into the header assembly 12. The liquid from the header as sembly 12 is conveyed by the return conduit 14 to the valve 15 and exits the valve through a suitable outlet 17 thereof.

The valve 15 has a temperature control element (not shown) of known construction and operation which operates to divert fluid flow from the inlet 16 of the valve 15 directly to its outlet 17 in the event that the temperature of the liquid is such that it does not require cooling and as is well known in the art whereby the valve 15 has its temperature control element and associated internal passages which cooperate to assure operation of the heat exchanger 10 as described above. It will also be appreciated that the effective flow area of the return conduit 14 is such that it offers less flow resistance than the combined areas of the tubes 13.

The header assemblies 1 1 and 12 are of known construction and include comparatively large,

volume chambers

18 and 19 respectively therein; and the tubes 13 have

opposite end portions

20 and 21 suitably fixed to such header assemblies in a fluid-tight manner utilizing any technique known in the art so that a fluid to be cooled by the heat exchanger 10 will flow under pressure into and out of the'heat exchanger and its component valve 15 with no leakage. For example, the

ends

20 and 21 may be brazed, welded, or mechanically swayed to their respective assemblies 11 and 12 while assuring unobstructed flow communication with the integral chambers of such assemblies.

The heat exchanger 10 has a plurality of planar fins each designated generally by the reference numeral 22 and as seen in FIG. 2, each fin 22 has one set or a first set 23 of integral tubular collars extending in one direction; i.e., upwardly, from the plane of the fin and another set or a second set 24 of integral tubular collars 7 extending in a direction opposite from the one direction, i.e., downwardly, from the plane of the fin. For convenience and easy discription thereof, each of the tubular collars regardless of whether it extends upwardly or downwardly is designated by the same refer ence numeral 25. The collars 25 and the remainder of the body of each fin 22 are made as a single piece construction.

As seen particularly in FIG. 3, the fins 22 are fixed against the tubes 13 in substantially parallel relation with the first set 23 of collars 25 of one fin, such as the lowermost fin shown at 26 in FIG. 3, adjoining and cooperating with the second set 24 of an immediately adjacent fin, shown at 27, to provide a precise spacing (indicated at 30 in both FIGS. 3 and 4) between the lower fin 22 and such adjacent fin 22. Indeed, the stacking of the fins 22 along the entire length of the tubes 13 is such that two sets of collars of each pair of immediately adjacent fins cooperate to provide the precise substantially large spacing 30 between fins.

The integral tubular collars 25 provided in each fin 22 are arranged in a plurality of parallel rows, see FIG. 2, each designated generally by the reference numeral 31; and, the collars in a particular row 31 are arranged so thatthey alternate in opposite directions perpendicular to the plane of the fin, i.e., one collar 25 extends upwardly followed by another collar 25 which extends downwardly, followed by another collar which extends upwardly, etc. It will also be seen that the collars 25 in an immediately adjacent pair of parallel rows 31 are arranged in staggered relation so that each collar 25 of the central 'row 31, for example, has its center arranged approximately one half the distance 33 between the centers of a pair of collars 25 in a near row 31 with such distance being measured parallel to such row.

Each of the collars 25 has an outwardly flared terminal end portion 35, as shown in FIG. 4, and such outwardly flared end portion 35 enables the collar to be more easily slid along its associated tube 13 and in particular' enables easier sliding of the inside surface 36 of such collar along the outside surface 37 of the tube 13. The flared end portion 35 is flared on a generous arc or radius 38 as viewed in cross section; and, the base of the tubular collar 25 is also blended with the main body of the fin on a generous are 39 as viewed in cross section and the

arcs

38 and 39 assure that the tubular collar 25 is formed substantially without stress concentrations. It will also be appreciated that the collars 25 may be formed using any suitable technique and preferably are formed first by punching small openings in the fin" stock at each location where a collar is to be formed and then simultaneously forming the collars 25 by cooperating punches and dies acting simultaneously.

The fins 22 may be fixed in position using any suitable technique and preferably such fins are fixed in position by expanding or forming each tube 13 radially outwardly a controlled amount so that its outside surface 37 is mechanicallyfirmly engaged against an associated collar 25 by engaging the inside surface 36 thereof. The tubes 13 and fins 22 may be fixed together after the opposed ends of the tubes are fixed to the header assemblies 11 and 12 or such tubes, fins, and header assemblies 11 and 12 may be fixed together in one operation by using appropriate fixtures. One technique which may be employed, for example, is to use a pencil-like tool having bulbous head which is moved axially through each tube 13 once the tubes 13 have been fixedinposition in their header assemblies; and, as the tool head is passed along the full length of the tube 13, it permanently mechanically radially expands the tubes 13 outwardly with their outside surfaces 37 firmly against the inside surfaces 36 of the collars 25.

The preferred thickness range of the fins was given previously herein and such fins may be used with tubing having any desired outside diameter. In one application of this invention, /8 inch O.D. tubing was used with inch spacing between the centers of the tubes 13 in each row and inch spacing between each immediately adjacent pair of rows; and, as indicated at two locations 40 in FIG. 2. However, it will be appreciated that any suitable tubing size and spacing may be used depending upon the application of the heat exchanger 1 As previously indicated, the fins 22 are preferably made of an aluminum alloy having an H-l9 temper and such fins 22 may be used with copper tubing, aluminum tubing, or any other metal tubing used in the art to make heat exchangers. Preferably, aluminum tubes 13 are made of either ll00 or 3003 aluminum alloy and when aluminum tubes are used the fins are'made of 7072 aluminum alloy. In heat exchangers which have tubes made of copper the fins are preferably made of 1100 alloy.

While present exemplary embodiments of this invention, and methods of practicing the same, have been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

1. A heat exchanger core assembly comprising a plurality of tubes arranged in substantially parallel relation and a plurality of fins made of an aluminous material having an I-I-l9 temper, each of said fins comprising a substantially planar sheet and two sets of tubular collars which are integral with said planar sheet and which engage and are supported concentrically around said tubes, one of said sets of tubular collars extending in one direction substantially perpendicular to the plane of said planar sheet and the other of said sets of collars extending in a direction opposite to said one direction, said fins being fixed against said tubes in a relation wherein the plane defined by each said planar sheet is substantially perpendicular to the longitudinal axis of each of said tubes with the said one set of collars of one said fin adjoiningand cooperating with the said other set of collars of an immediately adjacent fin to provide a spacing between said one and immediately adjacent fin.

2. An assembly as set forth in claim 1 in which each of said collars has an outwardly flared terminal end portion which enables easier sliding thereof along its associated tube for fin-stacking purposes.

3. An assembly as set forth in claim 1 in which each of said fins has a thickness ranging roughly between 0.010 inch and 0.002 inch.

4. An assembly as set forth in claim 1 in which said collars are arranged in a plurality of parallel rows and immediately adjacent collars in each row extend in opposite directions.

5. An assembly as set forth in claim 4 in which said collars in an immediately adjacent pair of parallel rows are arranged in staggered relation.

6. An assembly as set forth in claim 4 in which said collarsin each row have an equal spacing therebetween, said parallel rows have said equal spacing in a direction perpendicular thereto, and the collars in a row immediately adjacent another row are staggered roughly one-half way between the collars in said other I'OW.

Claims

1. A HEAT EXCHANGER CORE ASSEMBLY COMPRISING A PLURALITY OF TUBES ARRANGED IN SUBSTANTIALLY PARALLEL RELATION AND A PLURALITY OF FINS MADE OF AN ALUMINOUS MATERIAL HAVING AN H-19 TEMPER, EACH OF SAID FINS COMPRISING A SUBSTANTIALLY PLANAR SHEET AND TWO SETS OF TUBULAR COLLARS WHICH ARE INTEGRAL WITH SAID PLANAR SHEET AND WHICH ENGAGE AND ARE SUPPORTED CONCENTRICALLY AROUND SAID TUBES, ONE OF SAID SETS OF TUBULAR COLLARS EXTENDING IN ONE DIRECTION SUBSTANTIALLY PERPENDICULAR TO THE PLANE OF SAID PLANAR SHEET AND THE OTHER OF SAID SETS OF COLLARS EXTENDING IN A DIRECTION OPPOSITE TO SAID ONE DIRECTION, SAID FINS BEING FIXED AGAINST SAID TUBES IN A RELATION WHEREIN THE PLANE DEFINED BY EACH SAID PLANAR SHEET IS SUBSTANTIALLY PERPENDICULAR TO THE LONGITUDINAL AXIS OF EACH OF SAID TUBES WITH THE SAID ONE SET OF COLLARS OF ONE SAID FIN ADJOINING AND COOPERATING WITH THE END OTHER SET OF COLLARS OF AN IMMEDIATELY ADJACENT FIN TO PROVIDE A SPACING BETWEEN SAID ONE AND IMMEDIATELY ADJACENT FIN.

6. An assembly as set forth in claim 4 in which said collars in each row have an equal spacing therebetween, said parallel rows have said equal spacing in a direction perpendicular thereto, and the collars in a row immediately adjacent another row are staggered roughly one-half way between the collars in said other row.