US3462990A

US3462990A - Meshing gear apparatus for making heat exchangers

Info

Publication number: US3462990A
Application number: US584712A
Authority: US
Inventors: Harold J Loehlein; Edward E Curran
Original assignee: Reynolds Metals Co
Current assignee: Reynolds Metals Co
Priority date: 1963-12-23
Filing date: 1966-10-06
Publication date: 1969-08-26
Anticipated expiration: 1986-08-26

Description

Aug. 26, 1969 H J. LOEHLEIN ETAL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEKT EXCHANGERS 8 Sheets-Sheet 1 Original Filed Dec. 23, 1963 FIGJ FIG.3

INVENTORS HAROLD J.LDEHLE|N EDWARD E. CURRAN y mam ATTd RwEYs Aug. 26, 1969 H J. LOEHLEIN ET AL 3,462,990

MESHING GEAR APPARATUS FOR- MAKING HEAT EXCHANGERS Original Filed Dec. 23, 1963 8 Sheets-Sheet z INVENTORS {Z k? ssmaag E-z u s'ksr 6 BY (.47 vf r I," z

THEIR ATTORNEYS Aug. 26, 1969 H J. LOEHLEIN E AL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS 8 Sheets-Sheet 5 Original Filed Dec. 23, 1963 FIGS Aug. 26, 1969 H LOEHLEIN E L 3,462,990

mn'snnm GEAR APPARATUS FOR MAKING HEAT EXCHA'NGERS Original Filed Dec. 23, 1963 a Sheets-Shet 4 INVENTORS HAROLD J. LOEHLElN EDWARD E.CURRAN H J. LQEHLEIN ETAL MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS Original Filed Dec. 23, '1963 8 Sheets-Sheet 5 rab IN VENTORS HAROLD J. LOEHLEIN EDWARD E.CURRAN Fuenmam ATT6RNEY$ Aug. 26, 969 H J. LOEHLEIN ET AL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS original Filed Dec. 23, 1963 8 Sheets-Sheet 6 l N VENTORS HAROLD J. LOEHLEIN F G EDWARD ECURRAN BY Mm, n44

x THEIR ATTORNEYS Aug. 26, 1969 H J LQEHLEIN ETAL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS 8 Sheets-Sheet 7 Original Filed Dec. 23, 19 3 FIG.25

INVENTORS N 1 W EN 5 n E mm n/m m A T w W v n MWM m wR M E 0A m RW AD 2 EL Aug. 26, 1969 H J, LQEHLE|N ET AL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS Original Filed Dec. 23, 1963 8 Sheets-Sheet 8 INVENTORS HAROLD J. LOEHLEIN EDWARD E. CURRAN THEIR ATTORNEYS 3,462,990 MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS Harold J. Loehlein, Richmond, Va., and Edward E. Curran, Louisville, Ky., assignors to Reynolds Metals Company, Richmond, Va., a corporation of Delaware Original application Dec. 23, 1963, Ser. No. 332,818, now Patent No. 3,294,162, dated Dec. 27, 1966. Divided and this application Oct. 6, 1966, Ser. No. 584,712

Int. Cl. B21d 13/00, 13/04 US. Cl. 72-186 22 Claims ABSTRACT OF THE DISCLOSURE Meshing gear members have teeth adapted to cooperatively act upon a flange of a tubular workpiece so as to divide it to form fins, twist the fins, and draw and iron the fins, thereby increasing their surface area while decreasing their thicknesses.

This application is a divisional patent application of its copending parent patent application, Ser. No. 332,818, filed Dec. 23, 1963, now Patent No. 3,294,162.

This invention relates to an improved heat exchanger construction or the like as well as to improved methods and apparatus for making such a heat exchanger or the like.

It is well known that heat exchangers can be formed of a hollow tubular member through which a cooling or heating medium is circulated whereby the outer peripheral wall of the hollow tubular member forms the primary heat exchanger surface for heat transfer purposes.

In order to increase the heat transfer between the surrounding atmosphere and the circulating medium, various manufacturers provide fin means to be attached to the outer peripheral surface of the hollow tubular member to increase the surface area of the heat exchanger structure, the fins each forming what is commonly known as a secondary heat exchanger surface.

However, it has been found that the fins forming the secondary heat exchanger surfaces of the heat exchanger must be intimately placed in contact with the primary heat exchanger surface in order for the same to be effective whereby many manufacturing problems are encountered.

According to the teachings of this invention, such secondary heat exchanger surface is uniquely provided whereby the secondary heat exchanger surface is formed integrally with the primary heat exchanger surface in such a manner that an effective heat exchanger construction is provided.

In particular, one type of heat exchanger structure of this invention is provided by extruding a hollow tubular member from metallic material, such as aluminumcontaining metallic material or the like, with the hollow tubular member having an outwardly directed flange integrally interconnected thereto and substantially radiating from the longitudinal axis of the hollow tubular member.

Thereafter, the flange of the hollow tubular member is divided into a plurality of fins each having its surface area substantially increased over the surface area of the part of the flange from which the respective fin has been formed whereby an effective heat exchanger construction is provided in a rapid and simple manner,

As will be apparent hereinafter, the heat exchanger construction of this invention can be utilized in many applications for the transfer of heat in a simple and effective manner heretofore unobtainable by well known heat nited States Patent O 3,462,999 Patented Aug. 26, 1969 ice exchanger constructions whereby the heat exchanger constructions of this invention are relatively inexpensive.

Accordingly, it is an object of this invention to provide an improved heat exchanger construction having one or more of the novel features of this invention as set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved method for making such a heat exchanger construction or the like.

A further object of this invention is to provide an improved apparatus for making such a heat exchanger construction or the like.

Other objects, uses and advantatges of this invention are apparent from a reading of this description which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIGURE 1 is a perspective View illustrating one embodiment of the heat exchanger blank of this invention.

FIGURE 2 is a view similar to FIGURE 1 and illustrates another embodiment of the heat exchanger blank of this invention.

FIGURE 3 is a schematic, fragmentary, perspective view illustrating the method and apparatus for converting the blank of FIGURE 1 or 2 into the heat exchanger construction of this invention.

FIGURE 4 is an end view of the method and apparatus illustrated in FIGURE 3.

FIGURE 5 is a front view of one of the gear means of the apparatus of this invention.

FIGURE 6 is a cross-sectional view taken on lines 6-6 of FIGURE 5.

FIGURE 7 is a fragmentary, cross-sectional view taken in line 7-7 of FIGURE 6.

FIGURE 8 is a fragmentary, end view illustrating how the apparatus of FIGURE 3 forms the heat exchanger construction of this invention.

FIGURE 9 is a top view of the heat exchanger construction of this invention.

FIGURE 10 is a side view of the heat exchanger construction illustrated in FIGURE 9.

FIGURE 11 is a fragmentary, cross-sectional view taken on line 11-11 of FIGURE 10.

FIGURE 12 is a top plan view of an improved heat exchanger construction formed according to the teachings of this invention.

FIGURE 13 is a fragmentary, cross-sectional view taken on line 13-13 of FIGURE 12.

FIGURE 14 is a fragmentary, cross-sectional view taken on line 14-14 of FIGURE 13.

FIGURE 15 is a view similar to FIGURE 14 and illustrates the frame member of this invention before the same has been attached to the heat exchanger tube construction.

FIGURE 16 is a top plan view of another heat exchanger construction of this invention.

FIGURE 17 is a fragmentary, cross-sectional view taken on line 1717 of FIGURE 16.

FIGURE 18 is a fragmentary, cross-sectional view illustrating one application of the heat exchanger c011- struction of this invention.

FIGURE 19 is a cross-sectional view taken on line 19-19 of FIGURE 18.

FIGURE 20 is a fragmentary, cross-sectional view of the heat exchanger tube construction of this invention.

FIGURE 21 is a plan view of a house or the like.

FIGURE 22 is a fragmentary, enlarged, cross-sectional perspective view taken on line 22-22 of FIGURE 21.

FIGURE 23 is a cross-sectional view illustrating the heat exchanger construction of this invention in another application thereof.

FIGURE 24 is a cross-sectional view taken on line 2424 of FIGURE 23.

FIGURE 25 is a cross-sectional view of a domestic refrigerator or the like utilizing a heat exchanger construction of this invention.

FIGURE 26 illustrates another embodiment of this invention which can be utilized in the refrigerator of FIG- URE 25.

FIGURE 27 is an exploded perspective view of the parts illustrated in FIGURE 26.

FIGURE 28 illustrates another application of the heat exchanger construction of this invention.

FIGURE 29 is a cross-sectional view illustrating another application of the heat exchanger construction of this invention.

FIGURE 30 is a perspective schematic view of the structure illustrated in FIGURE 29.

FIGURE 31 is a fragmentary perspective view of another heat exchanger construction of this invention.

FIGURES 32 and 33 are views similar to FIGURE 31 and illustrate other embodiments of this invention.

FIGURE 34 is a view similar to FIGURE 8 and illustrates another embodiment of this invention.

While the various features of this invention are hereinafter described and illustrated as being particularly adaptable for forming a heat exchanger construction or the like, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide other constructions as desired.

Therefore, this invention is not to be limited only to the embodiments illustrated in the drawings, because the drawings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIGURE 1, the improved heat exchanger blank of this invention is generally indicated by the reference numeral 40 and comprises an elongated hollow tubular member 41 having one or more outwardly directed flanges 42 integrally interconnected to the outer peripheral surface 43 of the hollow tubular member 41.

While the heat exchanger blank 40 of this invention can be formed in any suitable manner and of any suitable material, the embodiment illustrated in FIGURE 1 is formed by extending metallic material, such as aluminumcontaining metallic material or the like, by a conventional extruding apparatus 44 in a conventional manner.

Thus, it can be seen that the heat exchanger blank 40 of this invention can be extruded in a simple and effective manner to provide a heat exchanger having the desired length in a manner hereinafter set forth.

Further, while the heat exchanger blank 40' of this invention can have any suitable dimensions, the embodiment thereof illustrated in the drawing has the outside diameter of the hollow tubular member 41 approximately of an inch while the thickness of each flange 42 is approximately 0.035 of an inch, the width of the flanges 42 being any desired width.

However, it is to be understood that the above dimensions and materials for forming the heat exchanger blank 40 of this invention are not a limitation on this invention as the same can vary as desired.

While the flanges 42 of the heat exchanger blank 40 of this invention are of uniform thickness throughout the length thereof, it is to be understood that the same can have a varying thickness throughout the length thereof, if desired.

For example, reference is made to FIGURE 2 wherein another heat exchanger blank is generally indicated by the reference numeral 40A and parts thereof similar to the heat exchanger blank 40 are indicated by like reference numerals followed by the reference letter A.

As illustrated in FIGURE 2, the flanges 42A extending outwardly from the hollow tubular member 41A respectively taper from the outer peripheral surface 43A of the hollow tubular member 41A to the outer free edges of the flanges 42A.

For example, should the outer tubular member 41A have an outside diameter of approximately /8 of an inch, the flanges 42 can be approximately 0.035 inch at the outer peripheral surface 43A of the hollow tubular member 41A and tapered downwardly to approximately 0.020 inch at the outer free ends thereof.

Therefore, it can be seen that the heat exchanger blanks and 46A of this invention can vary in the configuration thereof while still being adapted to form the heat exchanger constructions of this invention in a manner hereinafter set forth.

Therefore, since either the heat exchanger blank 40 or heat exchanger blank 40A can be utilized in the manner hereinafter described, only the heat exchanger blank 40 will be specifically referred to with the understanding being that the same description would apply to the heat exchanger blank 40A, if desired.

While the heat exchanger blanks 40 and 40A of this invention respectively have two diamtrically opposed flanges 42 extending from the

tubular member

41 or 41A, it is to be understood that the various features of this invention can be utilized with the

hollow tubular member

41 or 41A having one or any desired number of flanges 42 disposed in any desired relationship about the outer

peripheral surface

43 or 43A thereof whereby this invention is not to be limited to a heat exchanger construction having just two

flanges

42 or 42A as will be apparent hereinafter.

After the blank 40 has been formed in the above manner, the same has the flanges 42 thereof divided into a plurality of fins integrally interconnected to the hollow tubular member 41 to provide a unique secondary heat exchanger surface for the hollow tubular member 41, the fins each being formed from the flanges 42 and having the surface area thereof substantially increased over the part of the flange 42 from which the respective fin is formed in the manner now to be described.

Reference is now made to FIGURE 3 wherein an improved method and apparatus of this invention is generally indicated by the reference numeral 45 and is utilized to form the flanges 42 of the hollow tubular member 41 into a plurality of heat exchanger fins 46 integrally interconnected to the hollow tubular member 41 to provide a secondary heat exchanger surface therefor, each end 46 being formed from a part of the flange 42 and having the surface area thereof substantially increased over the original surface area of the part of the flange 42 from which the respective fin 46 is formed.

While the apparatus 45 illustrated in FIGURE 3 indicates that only one flange means 42 of the hollow tubular member 41 is being converted into fins 46, it is to be understood that the apparatus 45 of this invention can simultaneously form the fins 46 from the opposed flanges 42 of the hollow tubular member 41 in the manner illustrated in FIGURE 4.

The apparatus 45 comprises a pair of gear means 47 and 48 cooperating in a manner hereinafter described to operate on one flange means 42 of the hollow tubular member 41 and to rapidly and effectively convert the flange means '42 into the plurality of fins 46 in the manner illustrated in FIGURE 8 and which will be hereinafter described.

As illustrated in FIGURES 5-7, each gear means 47 and 48 is substantially identical to each other except that the gear means 47 has the teeth thereof pointing in one direction as illustrated in FIGURE 8 while the like teeth on the gear means 48 point in the opposite direction as illustrated in FIGURE 8 to perform the function of this invention.

Therefore, the gear means 48 will be described and illustrated in FIGURES 5-7 with the understanding that the gear means 47 is formed in the same manner except that the teeth thereof point in the opposite direction.

As illustrated in FIGURES 57 the gear means 48 includes a hub 49 having a cylindrical bore 50 passing therethrough to permit the gear means 49 to be fastened onto a suitable shaft by threaded members passing through threaded bores 51 formed in the hub 49.

The hub 49 of the gear means 48 has a plurality of teeth 52 radiating outwardly therefrom with each tooth 52 having a substantially arcuate leading surface 53 when the gear means 48 rotates in a clockwise manner in FIG- URE 5 while the trailing side 54 of the tooth 52 is substantially straight as illustrated in FIGURE 5.

As illustrated in FIGURE 8, each tooth 52 of the gear means 48 has a substantially flat outer end or land 55 which cooperates with the straight side 54 thereof to define a shearing edge 56 for a purpose hereinafter described. The leading side 53 of each tooth 52 of the gear wheel 48 curves arcuately from the point 57 to approximately the point 58 whereby the remainder of the surface 53 is substantially straight and parallel to the surface 54 until the surface 53 joins the hub 49 of the gear means 48. correspondingly, each tooth 52 of gear means 47 has a leading surface 53, a trailing surface 54', a land 55, and a shearing edge 56'. The teeth 52 of the

respective gears

47 and 48 are shaped so that they mesh to define a working depth or depth of engagement W substantially greater than the tooth thicknesses T at the working depth boundary nearest the tooth root, thereby providing for substantial relative traversing movement between said surfaces while said surfaces are adjacent each other.

As illustrated in FIGURE 6, each tooth 52 of the gear means 48 has a front side 59 which will be disposed in zone 59a adjacent the hollow tubular member 41 while the opposed side 590 of the tooth 52 will be remote from the hollow tubular member 41. The side 59 of each tooth 52 of the gear means 48 is arcuate, the land 55 gradually curving toward the axis of that gear means, in the manner illustrated in FIGURE '6 while the side 59c thereof is substantially straight. As is shown 'by FIGURES 6 and 8, the radius of curvature of the land 55 of each tooth 52 at its side 59 corresponds to the tooths working depth.

Further each tooth 52 of the gear means 48 at the side 59 thereof is rounded or arcuate in the manner illustrated in FIGURE 7.

This particular configuration of the teeth '52 of the gear means 47 and 48 form the fins 46 from the flange 42 of the hollow tubular member 41 in a unique manner now to be described.

As illustrated in FIGURE 8, the gear means 47 is rotating in a counterclockwise direction while the gear means 48 is rotating in a clockwise direction so that the teeth 52 thereof mesh in the manner illustrated in FIG- URE 8, the flange 42 of the hollow tubular member 41 either being passed through the nip of the rotating gear means 47 and 48 from left to right in the manner illustrated in FIGURE 8 or the gear means 47 and 48 can be moved from right to left while the hollow tubular member 41 is being held stationary even though the gear means 47 and 48 are rotating in the manner indicated by the arrows in FIGURE 8.

In any event, it can be seen that as the gear means 47 and 48 rotate, the teeth 52 on the gear means 47 begin to bend the flange 42 of the hollow tubular member 41 downwardly as represented by the gear teeth 52a and 52b in FIGURE 8. However, since the teeth 52a and 52b are arcuate at the surface 59 thereof as illustrated in FIG- URE 6, the portion of the flange 42 adjacent the hollow tubular member 41 is not bent downwardly as illustrated in FIGURE 8.

As the tooth 520 of the gear means 48 begins to move upwardly between the teeth 52b and 52d of the gear means 47 in the manner illustrated in FIGURE 8, it can be seen that the tooth 52c begins to move the flange 42 upwardly between the teeth 52b and 52d while utilizing the edge 56 thereof to cooperate with the edge 56 and surface 54 of the gear tooth 52b to shear the flange 42 into a particular fin 46a.

As the

gears

47 and 48 continue to rotate, it can be seen that the lower portion of each sheared fin 46 is drawn and ironed by the cooperating surfaces 53 on the adjacent teeth 52 of the gear means 47 and 48.

For example, it can be seen that the teeth 52e and 52f in FIGURE 8 are drawing and ironing the lower portion of the fin 46b to substantially elongate the same while the land 55 of the tooth 52e is moving the upper portion of the fin 46b back to a coplanar relation with the point of attachment of the fin 46b to the hollow tubular member 41.

As the gear teeth 52 of the gear means 47 and 48 pass through their fully meshed relation, it can be seen that the surfaces 53 of adjacent teeth 52 thereof cooperate together to draw and iron the top portion of each fin 46 to further elongate and substantially curve the same whereby the resulting fin 46 has a substantially S-shaped crossscctional configuration.

For example, see FIGURE 8 wherein the gear teeth 52g and 52h of the gear means 48 and 47 respectively begin to draw and iron the top portion of the fin 462.

Thus, it can be seen that as the flange 42 of the hollow tubular member 41 is passed through the nip of the meshing gear means 47 and 48, the teeth 52 on the gear means 47 and 48 cooperate together to shear and divide the flange 42 into individual fins 46 while at the same time drawing and ironing the fins 46 to substantially increase the surface areas thereof over the surface areas of the parts of the flange 42 from which the respective fins 46 are formed whereby the fins 46 provide an effective secondary heat exchanger surface for the resulting heat exchanger construction 60 illustrated in FIGURE 9.

As previously set forth, the apparatus 45 of this invention can comprise merely a pair of gear means 47 and 48 which will operate on a single flange 42 of the hollow tubular member 41 or can comprise four gear means as illustarted in FIGURE 4 for simultaneously operating on the opposed flange means 42 of the hollow tubular member 41 to form the heat exchanger construction 60.

In any event, the gear means of the apparatus 45 of this invention so form the fins 46 in the manner illustrated in FIGURES 9-11 that each fin 46 is integrally joined to the outer peripheral surface 43 of the hollow tubular member 41 by opposed gusset shaped

portions

61 and 62 as illustrated in the top view of FIGURE 9 to not only increase the strength or the particular fin 46 but to increase the surface contact thereof with the hollow tubular member 41 to promote the heat transfer in a manner well known in the hear exchanger art.

Such gusset portions '61 and 62 for each fin 46 are formed by having the surfaces 59 of the teeth 52 of the gear means 47 and 48 formed arcuately in the manner illustrated in FIGURE 7.

Further, each fin 46 has an inner portion 63 as illustrated in FIGURES 10 and 11 that curves arcuately and is joined to the remainder of the flange 42 to provide not only a structural relationship therewith, but also to increase the surface contact between the particular fin 46 and the outer peripheral surface 43 of the hollow tubular member 41.

Thus, it can be seen that the apparatus and method of this invention as illustrated in FIGURE 5 effectively divide the flange or flanges 42 of the hollow tubular member 41 into secondary heat exchanger surfaces comprising a plurality of fins 46 each having a surface area substantially increased over the surface area of the part of the flange 42 from which the respective fin 46 was formed.

For example, it has been found that the surface area of each fin 46 can be increased from at least 20% to over of the original surface area of the part of the flange 42 from which the respective fin 46 has been formed.

Thus, not only has the surface area of the fins 46 been increased in the above manner, but also the fins 46 are integrally interconnected to the outer peripheral surface 43 of the outer tubular member 41 whereby the most intimate contact is provided between the fins 46 and the hollow tubular member 41 to provide the heat transfer relationship required in a heat exchanger construction.

In addition, the fins 46 are so joined to the hollow tubular member 41 that the same are structurally attached thereto even though the same have been rendered relatively thin by the previously described drawing and ironing operation.

Thus, the apparatus and method of this invention effectively and simply form the heat exchanger construction 60 of this invention wherein the heat exchanger construction 60 has the advantages previously set forth.

After the desired length of the heat exchanger blank 40 has been formed into the heat exchanger construction 60, the heat exchanger construction 60 can be bent, coiled, spiraled, or remain straight for storage and shipment thereof for being formed into a particular configuration for a particular application thereof, the heat exchanger construction 60 of this invention being readily adaptable for most applications wherein a heat exchanger construction is needed.

For example, the heat exchanger construction 60 previously described can be sinuously bent in the manner illustrated in FIGURES 1215 to form another type of heat exchanger construction of this invention which is generally indicated by the reference numeral 64, the heat exchanger construction 64 being particularly adaptable as being utilized as an evaporator or condenser, as desired.

As illustrated in FIGURE 12, the heat exchaner construction 60 has been bent in a sinuous manner so that the same defines a substantially rectangular construction having elbows 65 at the opposed side of the rectangular construction and interconnecting together adjacent straight lengths 66 of the hollow tubular member 41, the hollow tubular member 41 being provided with its own inlet 67 and outlet 68 as illustrated in FIGURE 12.

If desired, the fins 46 on the hollow tubular member 41 can be removed in the region of the elbows 65 thereof as well as on the inlet 67 and outlet 68 thereof as illustrated in FIGURE 12.

In order to provide a rigid mounting construction for the sinuously bent tubular member 41, a pair of opposed frame members 69 are provided at the elbows 65 of the hollow tubular members 41 and attached thereto in a manner now to be described.

For example, each frame member 69 can comprise a lower portion 70 and an upper portion 71 defining a plurality of slots 72 therebetween which respectively receive the elbows 65 in the manner illustrated in FIGURE 15.

Therefore, it can be seen that each frame member 69 can be slipped onto the elbows 65 at one of the opposed sides of the sinuously bent hollow tubular member 41 with the elbows 65 being readily received and passing through the slots 72 therein.

Thereafter, the upper portions 71 of the frame member 69 are deformed downwardly in the manner illustrated in FIGURES 13 and 14 to effectively interlock the elbows 65 thereto without utilizing fastening members or the like whereby the frame members 69 provide a rigid unit with the hollow tubular member 41 and permit the same to be readily mounted in any desired relationship by mounting means 73 on the frame members 69.

Another type of heat exchanger construction of this invention can be formed from the structure 60 illustrated in FIGURE 9 to provide an evaporator, condenser or the like in a manner similar to the heat exchanger construction 64 previously described, reference being made to FIGURES 16 and 17 wherein another heat exchanger construction of this invention is generally indicated by the reference numeral 74.

As illustrated in FIGURES 16 and 17, the hollow tubular member 41 previously described is sinuously and substantially spirally wound or coiled in the manner illustrated in FIGURE 16 to define a substantially rectangular construction having elbows 75 at the opposed sides thereof and respectively interconnecting together adjacent 8

lengths

76 and 77 of the hollow tubular member 41, the hollow tubular member 41 having an inlet 78 and outlet 79 at the opposed ends thereof.

The coiled tubular member 41 is adapted to be formed into a rigid unit by a pair of opposed frame members 80 respectively interconnected to the elbows 75 of the bent tubular member 41.

For example, each frame member 80 can comprise a substantially U-shaped portion 81 in the manner illustrated in FIGURE 17 disposed against the outside of each elbow 75 at one side of the rectangular construction and a substantially cylindrical bar or portion 82 respectively passing through the elbows 75 in the manner illustrated in FIGURE 17 and detachably secured to the portion 81 by a plurality of threaded fastening members 83.

Thus, it can be seen that in the heat exchanger construction 74 illustrated in FIGURES l6 and 17, the fins 46 on the hollow tubular member 41 need not be removed in the region of the elbow 75 thereof, if desired, as the portions 82 of the frame members 80 eifectively interconnect the frame members 80 to the elbows 75, the inlet 78 and outlet 79 of the hollow tubular member passing effectively through suitable apertures formed in the portion 81 thereof as illustrated.

Therefore, it can be seen that unique heat exchanger constructions can be provided from the finned tubular member 41 of this invention to provide the desired heat exchanger function.

While the

heat exchanger constructions

64 and 74 of this invention are particularly adaptable for forming evaporators or condensers for refrigerating systems or the like, it is to be understood that the same can be utilized in other places where heat exchanger structures are required.

For example, reference is made to FIGURE 25 wherein a domestic refrigerator 84 is provided and has the conventional non-frozen food compartment 85 and the conventional frozen food compartment 86 respectively cooled by an evaporator 87 having air forced across the same by a suitable fan 88. Thus, the

heat exchanger constructions

64 and 74 of this invention are particularly adaptable for forming the heat exchanger construction 87 illustrated in FIGURE 25.

Thus, it can be seen that the finned tubular member 41 of this invention has many uses in the heat exchanger field and the same lends itself to particular configurations for particular heat exchanger applications.

For example, reference is made to FIGURE 18 wherein the finned tube 41 of this invention is disposed in spiral form that diminishes from left to right and is disposed in anhair duct 89 through which air is forced from left to rig t.

If desired, the spiral configuration of the finned tube 41 in FIGURE 18 can be reversed so that the smaller end thereof is first contacted by the flow of air through the duct 89 from the left.

Because of the simplicity of the construction of the finned tube 41 of this invention, it can be readily seen in FIGURES 18 and 19 that the same is readily adaptable to be formed in spiral form for the intended purpose thereof.

Instead of circulating a cooling medium through the finned tube 41 of this invention in the manner previously set worth, it is to be understood that the same could have a resistance wire 99 passed therethrough in the manner illustrated in FIGURE 20 which will be insulated from the interior wall of the hollow tubular member 41 by magnesium oxide 91 or the like in a conventional manner whereby the finned tube 41 can perform its heat exchanger function with the electrical heater element in a conventional manner.

For example, such an electrical heat exchanger element as illustrated in FIGURE 20 can be utilized as a baseboard heater for a home or building 92 illustrated in FIGURE 21 and having a baseboard 93 extending throughout the internal outer periphery thereof, the baseboard 93 comprising a conduit structure in the manner illustrated in FIGURE 22 whereby the finned tube 41 of this invention can pass through the baseboard 93 and be supported therein by suitable brackets 94.

In this manner, either a circulating heating medium can be passed through the hollow tubular member 41 in the baseboard 93 or the resistance wire 90 can be passed therethrough whereby the finned tube 41 of this invention will provide effective heating for the house or building 92 in a manner conventional in the art.

If desired, the finned tubular member 41 of this invention can be coiled upon itself in spiral fashion to provide a substantially flat heat exchanger construction for forming a condenser, evaporator, or the like for space heaters, air conditioning units, dehumidifiers and the like.

For example, reference is made to FIGURES 23 and 24 of this invention wherein a space heater is generally indicated by the reference numeral 95 and has the finned tubular member 41 thereof coiled upon itself to provide a heat exchanger through which air can be forced by a suitable fan 96 in a conventional manner, the finned tube 41 either having the desired medium circulated therethrough or having a resistance wire therein in the manner previously described.

If desired, the finned tube 41 of this invention can be disposed in substantially coiled cylindrical form in the manner illustrated in FIGURES 26 and 27 and placed in a suitable housing 97 to have air forced therethrough by a suitable fan 98, the coiled fin tube 41 of FIGURES 26 and 27 being particularly adaptable for domestic refrigerator use or the like although the same can be utilized in other places where a heat exchanger is desired.

Also, the finned tube 41 of this invention can be interconnected to an accumulator 99 in the manner illustrated in FIGURE 28 and be coiled about the accumulator 99 to provide means for transferring heat between the finned tube 41 and the accumulator 99.

In addition, the finned tube 41 of this invention can be utilized in an air conditioning unit or the like in the manner illustrated in FIGURES 29 and 30 whereby the finned tube is coiled to form an evaporator 100 and a condenser 101, the outlet of the condenser 101 being interconnected to the inlet of the evaporator 100 by a suitable capillary arrangement 102 while the outlet of the evaporator 100 is interconnected to a condenser 103 having the outlet thereof interconnected to the inlet of the condenser 101, suitable fans 104- and 105 being utilized to respectively direct air across the evaporator 100 and condenser 101.

Therefore, it can be seen that the finned tube 41 of this invention can be formed in a plurality of different shapes to form heat exchanger structures for particular applications thereof because the finned construction 41 of this invention is readily adaptable to be shaped in the desired configuration and can be simply and rapidly formed in the manner previously described whereby the overall cost of the heat exchanger constructions of this invention are relatively small when compared with prior known heat exchanger constructions.

In addition, the heat exchanger constructions of this invention have the specific advantage of the intimate contact between the primary and secondary surfaces thereof which is a feature heretofore unobtainable in the prior art.

While the various heat exchanger constructions of this invention can be utilized for many purposes as set forth above, the finned tubular member 41 is readily adaptable for forming a frost-proof evaporator for appliances, such as refrigerators and the like.

For example, reference is now made to FIGURES 31- 33 wherein the finned tube 41 of this invention is formed into an evaporator of desired design and has a heating element 106 coupled therewith, the heating element 106 being adapted to have electrical current periodically passed therethrough to cause the heating element 106 to heat the finned tube 41 to eliminate frost thereon in a conventional defrosting manner.

In particular, the heating element 106 can be coupled to the finned tube 41 by suitable clips 107 in the manner illustrated in FIGURE 31.

If desired, the finned tube 41 can have outwardly directed flanges 108 integrally extruded with the blank 40 as illustrated in FIGURE 32 whereby the integral flanges 108 can be utilized to hold the heating element 106 to the finned tube 41 by either being deformed around the heating element 106 or by having the heating element 106 snap-fitted between the preformed flanges 108.

Alternately, the heating element 106 can be passed directly through the finned tube 41 in the manner illustrated in FIGURE 33.

While the apparatus 45 of this invention has been previously described as having the fins 46 drawn, ironed and stretched by the cooperating sides 53 of the gear teeth 52 of the gear means 47 and 48, it has been found that the flat sides 54 of the gear teeth 52 of the gear means 47 and 48 can cooperate together to form the fins 46 on the blank 40 by shearing, drawing, stretching and ironing the flanges 42 of the blank 40 in a manner now to be described.

For example, reference is now made to FIGURE 34 wherein the gear means 47 and 48 are substantially the same as the gear means 47 and 48 of FIGURE 8 except that the blank 40 is passed therebetween in such a manner that the meshing gear teeth 52 shear, draw, stretch and iron the flange 42 in an upward direction to form the fins 46 between the cooperating straight surfaces 54 of the gear teeth 52.

It has been found that in the embodiment of FIGURE 34, increasing the offset relation of the

gears

47 and 48 increases the interference therebetween to increase the surface areas of the fins 46 over the surface areas of the parts of the flange 42 from which the respective fins 46 are made. In addition, this increased interference, and, thus, increased surfaces of the fins 46, can be further enhanced by providing a slight radius 109 on the ends of the sides 54 of the gear teeth 52 of the gear means 47 and 48 in the manner illustrated in FIGURE 34.

While the blank 40 has been previously described as being extruded, it is to be understood that the blank 40 could be made by other methods.

For example, the blank 40 could be formed by securing two flat sheets together with a longitudinal unsecured area therebetween which can be subsequently expanded to form the tubular portion 41, such as in the United States Patents to Long, No. 2,662,273, and to Grenell, No. 2,690,002, while leaving integral flanges, similar to flanges 42, which can be subsequently formed into the fins 46 by the methods previously described.

Therefore, it can be seen that not only does this invention provide an improved heat exchanger construction or the like, but also this invention provides improved methods and apparatus for making such a heat exchanger construction or the like.

While the form of the invention now preferred has been disclosed as required by the statutes, other forms may be used, all coming within the scope of the claims which follow.

What is claimed is:

1. Apparatus for making a heat exchanger from a hollow tubular member having an outwardly directed flange integral therewith, comprising a pair of rotatable meshing gear members whose teeth have lands which, in a common meshing zone on their widths, curve gradually inwardly toward the axis of rotation of their gear member.

2. The apparatus of claim 1 wherein the radius of curvature of said curve corresponds to the working depth of said teeth.

3. The apparatus of claim 1 wherein said lands on at least one gear member are adapted to restrain an edge of a fin divided from said flange, thereby enabling said fin to be drawn to increase its surface area while decreasing its thickness.

4. The apparatus of claim 1 wherein each said land connects the ends of its tooths leading and trailing surfaces, one of said surfaces being substantially flat and the other being convex near its end.

5. Apparatus for making a heat exchanger from a hollow tubular member having an outwardly directed flange integral therewith, comprising a pair of rotatable meshing gear members whose teeth have lands which, in a common meshing zone on their widths, curve gradually inwardly toward the axis of rotation of their gear member, said teeth on one said gear member having substantially flat trailing surfaces and leading surfaces convex near their ends, said teeth on the other said gear member having substantially flat leading surfaces and trailing surfaces convex near their ends, the ends of said substantially flat leading surfaces meshing behind the ends of said substantially flat trailing surfaces, said convex leading surfaces meshing behind said convex trailing surfaces, and said gear members being adapted to cooperate in rotation so that said flange in passing through their nip is sheared between shearing edges at the ends of said substantially flat surfaces to form fins with the radially outer portions of said fins twisted out of alignment with the original surface of said flange while said curved lands in said meshing zone allow at least part of the radially innermost portions of said fins to remain in alignment with said original surface, and so that said convex leading and trailing surfaces cooperate to draw and iron said fins therebetween to increase the surface area of said fins while decreasing their thickness.

6. The apparatus of claim 5 wherein said gear members are substantially identical.

7. Apparatus for making a heat exchanger from a hollow tubular member having an outwardly directed flange integral therewith, comprising a pair of rotatable meshing gear members whose teeth have lands at their ends and are so spaced and shaped as to enable said gear members to cooperate in rotation so that as a fin divided from said flange passes through the nip of said gears, a land of one gear member restrains one edge of said fin and a land of the other gear member restrains the other edge of said fin, whereby said fin is drawn therebetween to increase its surface area while decreasing its thickness.

8. The apparatus of claim 7 wherein said land on said other gear member restrains said fins said other edge by urging it against the leading surface of the said one gear members tooth whose land restrains said fins said one edge.

9. The apparatus of claim 8 wherein said leading surface of said one gear member and said trailing surface of said other gear member are convex near their ends and are adapted to iron said fin therebetween.

10. Apparatus for making a heat exchanger from a hollow tubular member having an outwardly directed flange integral therewith, comprising a pair of rotatable meshing gear members whose teeth have leading and trailing surfaces connected by lands at their ends, said teeth on one gear member having substantially flat trailing surfaces and on the other gear member having substantially flat leading surfaces, the intersections of said lands and substantially fiat surfaces constituting shearing edges, and said leading shearing edges on said other gear member meshing immediately behind said trailing shearing edges on said one gear member, whereby the shearing edges of the respective gear members are adapted to shear said flange to form fins and said lands are adapted to restrain said fins for drawing to increase their surface area while decreasing their thicknesses.

11. Apparatus for making a heat exchanger from a hollow tubular member having an outwardly directed planar flange integral therewith, comprising a pair of rotatable meshing gear members with teeth spaced and shaped to cooperate in rotation so that said flange in passing through their nip is divided to form fins, and the radially outer portions of said fins are twisted from the plane of said flange and drawn and ironed so as to increase their surface area while decreasing their thicknesses.

12. The apparatus of claim 11 whose teeth are shaped so as to allow the radially innermost portions of the fins to remain in said plane.

13. Apparatus for making a heat exchanger (60) from a hollow tubular member (41) having an outwardly directed planar flange (42) integral therewith, comprising a pair of rotatable meshing gear members (47, 48) whose teeth (52) have leading and trailing surfaces (53, 53' and 54, 54) connected by lands (55) at their ends, said lands (55) in a common meshing zone (59a) along their widths curving gradually inwardly toward the axis of r0- tation of their gear member (47 or 48), said teeth (52) on one said gear member (48) having substantially flat trailing surfaces (54) and leading surfaces (53) convex near their ends, said teeth (52) on the other gear member (47) having substantially flat leading surfaces (53') and trailing surfaces (54') convex near their ends (55), the intersections of said lands (55) and said substantially flat surfaces (54, 53) constituting shearing edges (56, 56), said leading shearing edges (56) on said other gear member (47) meshing immediately behind said trailing shearing edges (56) on said one gear member (48), said convex leading surfaces (53) meshing behind said convex trailing surfaces (54'), and said gear members (47, 48) being adapted to cooperate in rotation so that said flange (42) in passing through their nip is sheared between said shearing edges (56, 56') of the respective gear members (48, 47) to form fins (46a) with the radially outermost portions of said fins (46a) twisted out of alignment with the original plane of said flange (42) while said curved lands (55) in said meshing zone (59a) allow at least part of the radially innermost portions of said fins (46a) to remain in said original plane, and so that a land (55) of said one gear member (48) restrains one edge of a said fin (46a, 46b) and a land (55) of said other gear member (47) restrains the other edge of said fin (46a, 46b) against the leading surface (53) of the said one gear members (48) tooth (52) whose land (55) restrains said fins (46a, 46b) said one edge, whereby said fin (46a, 46b) is drawn therebetween and ironed between a said convex trailing surface (54') and the said convex leading surface (53) meshing therebehind, thereby increasing the surface area of said fin (46a, 46b, 46) while decreasing its thickness.

14. Apparatus for making a heat exchanger from a hollow tubular member having an outwardly directed flange integral therewith, comprising a pair of rotatable gear members with radially extending teeth meshing to define a working depth substantially greater than the thickness of a tooth at the working depth boundary nearest the root of said tooth, said teeth on one gear member having leading surfaces convex near their ends and on the other gear member having trailing surfaces convex near their ends, said leading surfaces meshing behind and being adapted to cooperate with said trailing surfaces during rotation of said gear members so that while said surfaces are adjacent each other there is substantial relative traversing movement therebetween.

15'. The apparatus of claim 14 wherein the trailing surfaces on the teeth of said one gear member and the leading surfaces of the teeth of said other gear member are substantially flat.

16. The apparatus of claim 14 wherein the trailing surfaces of the teeth of said one gear member and the leading surfaces of the teeth of said other gear member terminate in shearing edges.

17. Apparatus for making a heat exchanger from a hollow tubular member having an outwardly directed flange integral therewith, comprising a pair of rotatable meshing gear members with radially extending teeth which on one gear member have trailing surfaces terminating in shearing edges and leading surfaces convex near their ends, and on the other gear member having leading surfaces terminating in shearing edges and trailing surfaces convex near their ends, said leading shearing edges meshing immediately behind said trailing shearing edges and being adapted to cooperate therewith to shear said flange to form fins, and said leading convex surfaces meshing behind said trailing convex surfaces and being adapted to cooperate therewith to deform said fins.

18. The apparatus of claim 17 wherein said surfaces terminating in shearing edges are substantially flat.

19. The apparatus of claim 17 wherein the deforming of said fins includes drawing and ironing to increase their surface area while decreasing their thicknesses.

20. Apparatus for making, from a hollow tubular member having an outwardly directed flange integral therewith, a heat exchanger having drawn fins sheared and twisted from said flange, said apparatus comprising a pair of rotatable members with radially extending teeth, a tooth on one gear member having a rearward shearing edge and a forward surface convex near its end and a tooth on the other gear member having a forward shearing edge and a rearward surface convex near its end, said gear members being adapted to cooperate in rotation so that said flange in passing forwardly between their converging teeth is sheared between said shearing edges to form fins and the radially outermost portions of said fins are twisted by said convex forward and rearward surfaces out of alignment with the original surface of said flange, leaving at least part of the radially innermost portions of said fins to remain in alignment with said original surface.

21. The apparatus of claim 20 wherein said forward and rearward surfaces of each said tooth curve toward each other in a region where said tooth is adapted to shear the radially innermost portion of said flange.

22. The apparatus of claim 20 wherein the intersection of each tooth surface with the axis of rotation of its member is a curve in a region where said tooth is adapted to shear the radially innermost portion of said flange.

References Cited UNITED STATES PATENTS 2,596,997 5/1952 Harter 72--186 2,963,779 12/1960 Mosgard-Jensen 29157 3,191,418 6/1965 Modine 72196 1,932,610 10/1933 Tilley 184 2,347,957 5/ 1944 McCullough 165172 X 2,646,972 7/1953 Schmerd 165--184 2,792,050 5/1957 Edwards 29202 2,963,779 12/1960 Mosgard-Jensen 165172 X CHARLES W. LANHAM, Primary Examiner LOWELL A. LARSON, Assistant Examiner US. Cl. X.R.