US3368261A - Method of making heat exchangers - Google Patents

Description

Feb. 13,v 1968 T. F. PAULS l METHOD-OF MAKING HEAT EXCHANGERS .3 Sheets-Sheet 2 Filed March 30, 1965 6 MZK INVENTOR. ITG 3 TH/SROA/F PAI/L5 Bkwa Mm."

A 7' TOR/VE V Feb. 13, 1968 T. F. PAULs METHOD OF MAKING HEAT EXCHANGERS 3 Sheets-Sheet 5 Filed March ISO, 1965 @n m M INVENTOR. g THE/QONFPAULS BY gd@ ATTORNEY 3,363,261 METHD F MAKING HEAT EXCHANGERS Theron F. Pauls, Godfrey, Ill., assigner to @lin Mathieson Chemical Corporation, a corporation of Virginia Filed Mar. 30, 1965, Ser. No. 443,900 8 Claims. (Cl. 29-157.3)

ABSTRACT 0F THE DISCLSURE In the method of producing a heat exchange device from a panel having provided therein a plurality of iutegral tubes coextending with each other in substantially spaced relationship, said tubes being expanded out of corresponding opposite faces of said panel, the improvemeut comprising the step of forcing a major portion of the area of the panel on one side of each of said tubes out of the plane of said panel in a first direction while forcing a major portion of the area of the panel on the other side of each of said tubes out of the plane of said panel in a second direction opposed to said first direction, thereby rotating each of said tubes out of the plane of said panel.

This invention relates in general to heat exchanger construction, and more particularly to the fabrication of heat exchanger structures of the multiple parallel tube type.

A commonly used and eiicient type of heat exchange unit adapted to serve as an evaporator, air conditioner, condenser, internal combustion engine cooling radiator or the like is formed from a plurality of superimposed sheets of metal having internally disposed between the sheets a number of conduits generally in a parallel spaced arrangement extending from a first or intake header to a second or outlet header. One or more of such units may be employed, and the conduits or tubes serve to carry an internal heat exchange medium such as Water or other coolant in conductive relationship with an external medium such as air or other fluid passing between the tubes. This type of constru-ction is typ-ical of automobile radiators where, for example, the heated water issues from the heated block of the engine with the aid of a pump, first enters one of the two headers, and then passes through a great number of thin-walled, relatively dat, closely spaced tubes between which cooling air is blown and which extend usually vertically from one to the other of the headers. Condensers are also frequently of the same type of construction.

According to one heretofore known method of manufacturing illustrated in U.S. Patent 2,690,002, this type of heat exchange unit may be readily manufactured to provide a great multiplicity of tubes in a sheet of metal. This method involves the application of a suitable predetermined pattern of weld-inhibiting material between component sheets, pressure welding all adjoining areas except those separated by the weld-inhibiting material thereby forming a unified composite panel, and inating along the unwelded areas to erect the tubes integral with the resultant tubed Lpanel. Full advantage heretofore has not been taken of this method, as the tubes formed are of rather flat or oval shape with the cross-sectional major dimensions thereof lying within or parallel to the panel in which the tubes are formed. In many applications it is desirable that the cross-sectional major dimensions of the tubes be oriented at an angle to the plane of the panel; this design adapts the units to fabrication as single pieces of large size, a number of which may then be put together for installations where the external medium passes through perforations in the panel transversely, rather than passing parallel to the panel along its surface.

In accordance with this invention it has been found nited States Patent O that the above-noted attributes may be obtained by treating a metal panel formed in accordance with the abovementioned U.S. Patent 2,690,002, in a unique manner. The panel may be formed with a multitude of parallel tubes, the areas on the two sides of ea-ch tube forced upwardly and downwardly to rotate the tube therebetween from its original position, simultaneously extending the metal between the tubes. The area between the tubes may then be perforated in a number of ways to allow for passage of a heat exchange medium through the sheet and across the tubes. The area between the tubes may also be treated to provide secondary heat exchange areas to improve the heat transfer characteristics of the device. This construction, while extremely simple to fabricate and assemble, presents a practical and highly efficient heat exchanger adapted to provide a maximum amount of external heat exchange medium ow between the tubes with a minimum amount of turbulence or impediment thereto.

Having thus generally described my invention, it becornes a principal object thereof to provide a compact and highly efficient heat exchange device adapted for transfer of heat between an internal and external heat exchange medium.

Another object of the present invention is to provide a heat exchange device having a plurality of parallel heat transfer tubes interconnected between a pair of headers for maximum flow of an internal heat transfer medium.

Still another object of the present invention is to provide a heat exchange `device having a plurality of heat exchange tubes interconnected between a pair of headers, the tubes being elongate in cross-section with the crosssectional major dimension of the tube being disposed at substantially right angles to the normal plane of the panel from which the device is fabricated.

Still another object of the present invention is to provide a heat exchange device having a plurality of heat exchange tubes interconnected between a pair of oppositely disposed headers, wherein the tubes are rotated 90 from the normal plane of the panel from which the device is fabricated to position the cross-sectional major dimension of the tube at substantially right angles to the normal plane of said panel.

Yet another object of the present invention is to provide such a heat exchange device which is highly efficient, compact, and economical to manufacture.

Still another object of the present invention is to provide a novel method of fabricating a heat exchange device having the above attributes.

Other objects and advantages will become apparent to those skilled in the art as a detailed description of a particular embodiment proceeds with reference to the drawings which form a part hereof, and in which:

FIGURE 1 is a plan View of a blank employed in the instant invention;

FIGURE lA is a perspective view of a portion of the blank of FIGURE 1 illustrating -a modification thereof;

FIGURE 2 is a cross-section taken along the lines II-II of FIGURE l to show the internal construction of the blank;

FIGURES 3-6 are views similar to FIGURE 2 during subsequent steps of the manufacture;

FIGURES 7 and 8 are cross-sectional views similar to FIGURE 6 illustrating two modifications;

FIGURE 9 is a partial plan view of a heat exchange device illustrating the modifications of each of FIGURES 6-8.

Referring now to the drawings and particularly to FIG- URE l, there is seen an illustrative embodiment employing a blank indicated generally by 10 produced as set forth in greater detail in the above-mentioned U.S. Patent 2,690,002. In accordance with that method, two

sheets 11 and`12 are superimposed with a pattern of weld-inhibiting material indicated generally by 13 situated between the sheets 11 and 12. As known in such method, the pattern 13 is a foreshortened version of the desired pattern of tubes in the finished article. This pattern consists of a pair of parallel bands 14 and 15 which are spaced apart adjacent a pair of opposite edges of the stack of sheets formed of individual sheets 11 and 12. interconnecting the two bands 14 and 15 are a plurality of bands 16 of weld-inhibiting material which cover the extent of sheets 11 and 12 intermediate bands 14 and 15 except for elongated parallel islands 17 which are free of weld-inhibiting material, and which also extend between the bands 14 and 15. It will be apparent that the bands 14 and 15 correspond to the headers in the finished article, and that the bands 16 correspond to the plurality of interconnecting tubes. In order to provide ingress and egress apertures for a heat transfer medium, the bands 14 and 15 are extended to an edge of stacked sheets 11 and 12 as indicated .at 18 and 19. It will also be evident that a marginal portion of sheets 11 and 12 along opposite sides transverse to the aforementioned opposite side has been left free of weld-inhibiting material 13 and is surrounded by a peripheral marginal area 20 with the exception of the strips 18 and 19 extending to one of the transverse edges.

For reasons to become evident, one or more of the islands 17 may additionally have provided a single band 21 of weld-inhibiting material, as seen in FIGURE l, or a plurality of bands 21, as seen in FIGURE 1A. The bands 21 or 21 are entirely isolated from the bands 14, 15, and 16. Also for reasons to become evident, each of the islands 17 may be perforated at each end thereof, as shown in FIGURE l at 22.

The stack of component sheets 11 and 12 with the weldinhibiting material 13 sandwiched therebetween is then temporarily secured together as by clamps, spot welding or the like to prevent relative movement between the sheets 11 and 12. The assembly thus formed is then heated to the required temperature and set through a pair of pressure rolls which exert sufficient pressure on the stack to firmly weld the sheets 11 and 12 together into a single integrated panel in the areas not coated with the weldinhibiting material 13. Simultaneously with the bonding operation, the sheets 11 and 12 undergo a substantial reduction in thickness as well as an elongation in the direction of rolling whereby the foreshortened pattern of weld-inhibiting material is stretched to a length corresponding to the desired pattern of tubes in the finished article. FIGURE 2 illustrates in cross-section a portion of the blank after such processing. The unified panel P results from the above-noted bonding of sheets 11 and 12 throughout their contacting surfaces not separated by weld-inhibiting material, portions of which appear at 16 in FIGURE 2.

Referring again to FIGURE l, it will be evident that i all areas are bonded except those indicated by the pattern of weld-inhibiting material 13. The islands 17, which ofcourse become bonded, may then be perforated at each end thereof, as at 22, for reasons to become evident. The perforations extend entirely through the panel P, and cover a major portion of the width of each of the islands 17.

The pattern 13 may be subsequently infiated by introduction of fluid-distending pressure. Thus, all areas covered by the pattern of weld-inhibiting material 13 will -be distended to the desired shape in accordance with the characteristics of the fiuid-distending pressure. For example, `as seen in FIGURE 3, parallel tubes 23 will be developed from the areas 16 of weld-inhibiting material shown in FIGURE 2. It will be evident that all areas of the blank not having weld-inhibiting material applied thereto will remain undistended.

The inflated panel P, as shown in part in FIGURE 3, may then be treated in accordance with this invention to rotate the tubes 23 out of the plane of the panel P shown in FIGURE 3. Referring to FIGURE 4, this rotation may be best accomplished by forcing the areas 24 between adjacent tubes 23 alternately up and down, thus rotating each of the tubes 23 between two such areas 24. For example, a series of parallel bars 25 acting on the upper face of the blank 12, between perforations 22 may `be forced downwardly against alternate areas 24, in the direction shown by the arrows 25. Simultaneously, a series of parallel vbars 26 also contacting the panel between perforations 22 may force the remaining alternate areas 24 upwardly, in the direction shown by the arrows 26. The motion of the areas 24 is materially facilitated by the presence of perforations 22. Were it not for the perforations 22, the end portions of portion 24 would resist movement and impede the proper rotation of the tubes 23 at such end portions. Accordingly, the portions 24 illustrated in FIGURES 4 and 5 may be thought of as the portions of islands 17 between the perforations 22, as seen in FIGURE l.

Considering again FIGURE 5, the action described above will force the areas 24 alternately up and down, necessarily rotating each of the tubes 23 between adjacent areas 24 into a position rotated from its former position. As shown, the tubes 23 have been rotated approximately but it will be evident that by appropriate control of the movement of bars 25 and 26, the tubes 23 may be rotated any desired angle. As the tubes 23 rotate, the areas 24 become reduced in thickness and extended in length due to material ow occasioned by the action of the bars 25 and 26 in forcing the areas 24 from their previous positions. Thus, the effective heat exchange surface of the areas 24 is materially increased.

The areas Z4 may then be perforated in any number of fashions so as to provide access of a heat exchange medium through the areas 24 and accordingly across the tubes 23. As seen in FIGURE 6, for example, this may be accomplished by merely punching a number of perforations 27 of any desired shape in each of the areas 24. Thus, as seen in the plan view of FIGURE 9, there will be provided a number of such perforations 27 throughout the length of the island 17 allowing for plenary passage of a heat exchange medium.

Alternately, if it is desired to further increase the area of the material within the portion 24, a louver 28 may be struck out from the area 24 and rotated at an angle to the plane of portion 24, for example 90. Subsequently, this louver 28 may be extruded to thin out its surface and increase its length to provide a larger and thinner louver 28', further increasing the effective heat exchange surface of such louvers. FIGURE 9 illustrates the final position of the extruded louver 28 and the area 29 of the portion 24 from which the louver was struck.

A still further method of forming perforations through the areas 24 is illustrated in FIGURE 8. This method requires that the island 17 shown in FIGURE 1 must have been previously provided with one or more -additional bands of weld-inhibiting material applied at the same time that the pattern 16 was applied. One band may be applied between sheets 11 and 12, as can be seen in FIG- URE l at 21. A plurality of bands may be applied by providing additional sheets when forming the composite blank. Thus, as can be seen in FIGURE 1A for example, a first band 21 may be interposed between sheets 11 and 11', and a second band 21' may be interposed between sheets 12 and 12. The pattern 16 may be then interposed between sheets 11' and 12 and the composite blank treated in the manner indicated above with reference to the blank of FIGURE 1.

In any event, the bands 21 or 21 are not inflated when the pattern 16 is inflated. Instead, these areas 21 or 21 remain undistended during the rotation of the tubes 23, see FIGURE 8. Portions of the area 24 may then be struck out and rotated in much the same fashion as were the louvers 28. However, when such an area is struck out and rotated, for example 90 as shown at 30 in FIG- URE 8, it may be subsequently inflated by application of fluid-distending pressure to the areas 21 or 21 within the louver 30. Thus, as seen in FIGURE 9, the louver 30 which was struck out and rotated from the area shown as 31, may subsequently be provided with one or more internal hollow tubes 32. Such construction materially increases the area` of heat exchange surface available to the heat exchange medium passing through the areas 24.

It will be appreciated that the number of perforations shown herein are merely exemplary and that any number of such perforations may be provided. For example, a greater or lesser number of perforations 27 as shown in FIGURE 6 may be employed; additional louvers 28 as shown in FIGURE 7 may be provided in each of the portions 24; and one or more of the lovuers 30 as shown in FIGURE 8 may be provided in each of the areas 24, with each of the louvers 30 having any number of desired internal tubes 32.

It will be evident that each of the resultant panels shown herein may be used alone or stacked up with a plurality of like panels to form a heat exchanger core structure of the multiple-tube type where the tubes of one plate are staggered with respect to the tubes of an adjacent plate and where the tubes of each plate are juxtaposed opposite the fins of an adjacent plate. Similarly, as much heat exchange capacity as required may be achieved by arranging the heat exchange units in multiples with the headers of the several units being connected in parallel.

It will be evident from the foregoing description and accompanying drawings that there has been provided a heat exchange device and method for making the same which is believed to provide a solution to the foregoing problems and achieve the aforementioned objects. It is to be understood that the invention is not limited to the illustrations described and shown herein which are deemed to be merely illustrative of the best modes of securing out the invention and which are susceptible of modification of form, size, arrangement of parts, .and detail of operation, but rather is intended to encompass all such modifications as are within the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. In the method of producing a heat exchange device from a panel having provided therein a plurality of integral tubes coextending with each other in substantially spaced relationship, and connected to at opposite ends thereof integral inlet and outlet headers, said tubes and headers being expanded out of corresponding opposite faces of said panel, the improvement comprising providing slots between said tubes adjacent said headers and forcing a major portion of the area of the panel on one side of each of said tubes out of the plane of said panel in a first direction while forcing a major portion of the area of the panel on the other side of each of said tubes out of the plane of said panel in a second direction opposed to said first direction, thereby rotating each of said tubes out of the plane of said panel, said headers being substantially unchanged by the said forcing operation.

2. The method of claim 1 including the step of perforating each of the areas between said tubes at opposite ends thereof prior to forcing said areas out of the plane of said panel.

3. The method of claim 2 further including the step of perforating the areas between said tubes forced ont of the plane of said panel.

4. A method of fabricating a heat exchange device from a composite panel formed of two superposed sheets having a pattern of Weld-inhibiting material interposed between said sheets, said pattern including a pair of parallel spaced-apart bands located adjacent opposite edges of said composite panel and extending to a transverse edge of said panel and a plurality of closely spaced-apart bands lying parallel to said transverse edge and joined at opposite ends with said pair of bands, said pair of bands and plurality of bands thereby defining islands free of said weld-inhibiting material, said method comprising the steps of (A) expanding said pair of bands to form headers and plurality of bands to form tubes within said composite sheet having their cross-sectional major dimensions parallel to the plane of said composite sheet,

(B) providing at least two slots on said islands, one

slot adjacent each header,

(C) forcing alternate of said islands upwardly out of the plane of said panel and forcing a major portion of the remainder of said islands downwardly out of the plane of said panel, thereby rotating said tubes to position the cross-sectional major dimensions thereof at an angle to the plane of said panel, said headers being substantially unchanged by the said forcing operation.

5. The method of claim 4 further including the step of perforating said islands in their position forced out of the plane of said panel.

6. The method of claim 5 wherein said step of perforating comprises slitting a portion of each of said islands and rotating said portion out of the plane of said island.

7. The method of claim 6 further including the step of thinning and extending said portion.

8. The method of claim 5 further including the steps of (A) applying at least one additional pattern of weldinhibiting material within each of said islands upon formation of said composite sheet,

(B) slitting a portion of each of said islands in their position forced out of the plane of said panel, and

(C) expanding the additional pattern of weld-inhibiting material within said portion to form passageways within said portion.

References Cited UNITED STATES PATENTS 2,894,731 7/ 1959 Wurtz.

2,926,003 2/ 1960 Pulsifer.

2,999,308 9/1961 Rauls.

3,178,806 4/1965 Keith 165-171 JOHN F. CAMPBELL, Primary Examiner.

CHARLIE T. MOON, Examiner.

I. C. CLINE, Assistant Examiner.

Images