CN111133269B

CN111133269B - Pipe connection

Info

Publication number: CN111133269B
Application number: CN201880062389.9A
Authority: CN
Inventors: C·克萨达·萨博里奥
Original assignee: C KesadaSaboliao
Current assignee: C KesadaSaboliao
Priority date: 2017-09-26
Filing date: 2018-09-26
Publication date: 2024-03-05
Anticipated expiration: 2038-09-26
Also published as: JP7203097B2; WO2019064067A2; BR112020006005A2; MX2020003676A; KR102448720B1; CR20200175A; JP2021509164A; KR20200055777A; BR112020006005B1; CA3076953C; CN111133269A; CA3076953A1; EP3688398A2; WO2019064067A3

Abstract

By extruding the raw tube with channels or micro-channels, the connection of the thin heat exchanger tubes to the manifold header is improved. The tubing is removed from the spaced areas of the central portion, leaving a finned thin heat exchanger central portion and a thicker head portion. The tube is curved, twisted and inclined. The tubes are aligned horizontally, vertically or at an angle and the head portions are welded together. The tubing is removed from the end of the head portion to form an end face having a protrusion, wherein the protrusion extends from the end face and surrounds the channel or microchannel. End plates having openings for receiving the projections are attached and sealed to the projections and end surfaces by welding or brazing. The panels are joined and sealed to the openings of the header tank by welding or brazing. The tube ends are flattened. A ring is added. The ends and rings are friction welded, avoiding the area around the passage opening, and polished.

Description

Pipe connection

The present application claims the benefit of U.S. provisional application Ser. No. 62/563,382, filed on publication No. 9/26 at 2017, which is incorporated herein by reference in its entirety as if fully set forth herein.

Background

There are a number of problems in heat exchangers and air conditioning systems. Heat transfer tubes with additional fins have many connections. Attaching fins to tubes is a problem. Connecting the ends of the tubes to the header tank is a more serious problem. When the connection breaks, leaks can occur that drain internal fluids causing damage to heat exchangers used in, for example, air conditioning, heat, power and refrigeration systems. Vibration and bi-metallic cell corrosion cause breakage of the connection.

The ends of the heat exchanger tubes are connected to openings in the header tank at the ends of the tubes. Connecting the tube to the header tank by friction welding is not a solution because of the relatively thin tube ends being deformed. The friction temperatures required to melt and weld the tube ends and heads deform the tube ends and ports/channels and destroy them.

There is a need to address the heat exchange leakage problem and tube to header connection problem in heat exchangers.

Disclosure of Invention

The present invention solves the problem of leakage damage in heat exchangers, for example for use in thermal, electrical, air conditioning and refrigeration systems.

The present invention provides a tube having a relatively thin central portion to facilitate heat exchange, and a tube having a larger, thicker end portion for connection to a head. The larger end of the tube is machined flat. Material is removed from the flattened end to leave a protrusion of material with a channel around the tube.

An opening is formed in the head to receive the shape of the material surrounding the channel in the tube. In one embodiment, the larger tube ends fit together in the head panel. The pipe ends themselves are joined together and to the head panel by friction welding or brazing. The protrusions of the tube ends are friction welded or brazed into the openings of the header plate. When the pipe ends are joined together by brazing, the protrusions of the pipe ends protrude into the head chamber from the sides of the head panel. The braze extends from the sides of the tube end, between the flattened surface of the tube end and the header panel, and along the protrusions extending through the openings in the header panel.

When the tube ends and projections are welded to the header panel, the tube ends are flush with and welded to the header panel opening on the header side of the panel. The edges of the tube ends and the larger flat tube ends are friction welded to the header panel. The intersecting edges of the head panel and the head body are friction welded together.

Important features of the new invention are and include:

the larger end on the heat exchange tube,

an angular or circular pattern at the transition point of the tube thickness when going from the thicker portion to the thinner portion of the tube, and vice versa,

connecting the larger end to the heat exchanger panel and/or,

connecting the larger ends of the heat exchanger tubes to each other,

flattening the end face of the enlarged end of the heat exchanger tube,

removing material from the flattened ends of the heat exchanger tubes to form protrusions surrounding the internal passages within the tubes,

inserting the protrusion into the opening of the heat exchanger header connector panel,

connecting the protrusions and the flat surfaces of the heat exchanger tubes with the heat exchanger head panel,

friction welding the edges of the protrusions and the edges of the larger ends to the corresponding edges of the heat exchanger head panel,

during brazing, the protrusions are made to extend through and beyond the panels, and the flat, larger end surfaces of the protrusions and tubes are brazed to the heat exchanger panels,

all enlarged ends are connected together in a fixed pattern,

wherein the fixed pattern is circular.

The present invention provides a tube having one or more channels and having a long, thin central heat exchange portion and a shorter terminal head portion. The terminal head portion is thicker than the thinner central heat exchange portion. There is an angular or circular pattern at the tube thickness transition point. The end face of the terminal portion is machined or flattened to provide a protrusion extending around and protecting the one or more channels outwardly. The outward protrusions extend from smooth, planar end surfaces on the thick terminal head portion.

The end plate has an internal opening for receiving the outward projection. The end plate has an inner surface that abuts, attaches to and seals against an end face of the terminal head portion. The inner opening of the end plate is connected and sealed to the outwardly directed projection of the end face of the terminal portion.

In one embodiment, the end plate and the outward projection are coextensive from the end face of the tube. The end plates are welded to the end faces of the terminal head portions and to the outward protrusions on the end faces of the terminal head portions.

In another embodiment, the outward protrusions extend beyond the face plate, and the face plate is brazed to the outward protrusions. The protrusions extend beyond the face plate to prevent migration of braze material into the tube channels.

The tube is extruded and the opposite surfaces of the middle portion of the tube are machined or ablated to remove portions of the tube and leave spaced apart fins integrally formed on the thinned middle portion. The fins are inclined relative to the longitudinal direction of the intermediate portion of the tube and the one or more channels are one or more micro-channels.

A plurality of similar extruded tubes have channels within the tubes. Material is removed from the middle portion of the tube and spaced apart fins are left on the thin middle portion. Thick terminal head portions are left on the ends of the plurality of tubes having an angular or circular pattern at the tube thickness transition points. The plurality of tubes are aligned horizontally or vertically, or are bent, twisted and tilted, wherein the twisted and tilted tubes are in a parallel helical relationship. The end heads of the plurality of tubes are aligned and joined together by welding prior to machining or ablating the ends of the plurality of connected end head portions to form the plurality of end faces and the plurality of outward protrusions on the plurality of end faces. A plurality of outward protrusions extend around and protect the channel. A plurality of outward protrusions are engaged to the flat end plates or the inner and outer peripheral rings. The end plate has a plurality of internal openings that receive a plurality of outward protrusions on a plurality of end faces of the joined terminal head portions. The plurality of inner openings of the end plate are welded or otherwise joined to the plurality of outwardly directed protrusions. The end plates are welded or otherwise bonded to the plurality of end faces.

The new method includes extruding a wide and thick tube with channels, then machining or rounding the central portion of the tube, removing material from the spacer portion from the central portion, thinning the central portion, forming fins across the tube and leaving thicker terminal head portions at the ends of the tube, having an angular or circular pattern at the tube thickness transition points, arranging the tubes parallel to one another, and welding or otherwise connecting the ends of adjacent tubes.

The ends of the connected terminal head portions are machined or flattened to form end surfaces with outwardly directed protrusions that extend around and protect the channels.

An end plate having an opening for receiving the outward projection is provided and welded or otherwise joined to the end face and the projection such that the end plate is readily joined to the head box at the end of the tube, or an inner peripheral ring and an outer peripheral ring are provided and welded or otherwise joined such that the rings are readily joined to the head box at the end of the tube.

The outward protrusions extend through and conform to the thickness of the end plates so that the end plates are easily welded to the end faces and protrusions by friction stir welding or hybrid friction diffusion welding.

The outward protrusions extend through and beyond the end plates so that the end plates and protrusions are easily brazed. The end plates may be brazed or welded to the end faces.

The connection of thin heat exchanger tubes to a manifold header is first improved by extruding thick tubes with channels or microchannels. The tubing is removed from the spaced areas of the central portion leaving fins on the thinner heat exchanger central portion and thicker terminal head portions. The finned center section of the tube is curved, inclined and twisted. The tubes are aligned horizontally, vertically or at an angle and the terminal head portions are welded together. The tubing may be removed from the end of the head portion to form an end face with the protrusions extending from the end face and surrounding the channels or microchannels. End plates having openings for receiving the projections are attached and sealed to the projections and end surfaces by welding or brazing. The attachment and sealing of the panels to the openings of the header tank by welding or brazing solves the problem of connecting the thin heat exchanger tubes to the manifold header tank.

The tube has one or more passages extending therethrough and has an elongated central portion and a shorter head portion. The head portion is thicker than the central portion. In one embodiment, the end face of the head portion has an outward projection extending around the one or more channels. The outward protrusions extend outwardly from the end face of the thick terminal head portion. The one or more channels are one or more micro-channels.

The end plate has an interior opening that receives the outward projection. The end plate has an inner surface that abuts and adheres to an end face of the head portion. The inner opening of the end plate is attached to an outwardly facing projection of the terminal portion.

In some embodiments, the end plate and the outward projection are coextensive from the end face of the tube, and the end plate is welded to the end face and to the outward projection on the end face of the head portion. In other embodiments, the outward protrusions extend beyond the panel, and the panel is brazed to the outward protrusions.

The tube is extruded and opposed parallel surfaces of the intermediate portion of the tube are machined to remove material from the tube and leave spaced apart fins integrally formed on the intermediate portion. In some embodiments, the fins are inclined relative to the longitudinal direction of the middle portion of the tube.

The plurality of similar extruded tubes have channels in the tubes and material is removed from the middle of the tubes, the spaced apart fins remain in the middle of the plurality of similar tubes and thick head portions remain at the ends of the plurality of tubes. The head portions of the tubes are aligned and welded or otherwise joined together prior to machining the ends of the plurality of joined head portions of the tubes and forming the plurality of end faces and the plurality of outward protrusions on the plurality of end faces. A plurality of outward protrusions extend around the channel in the conduit. The end plate has a plurality of internal openings for receiving a plurality of outwardly directed protrusions on the end face of the attached head portion. The plurality of interior openings of the end plate are welded, brazed or otherwise joined to the plurality of outward protrusions, and the end plate is welded or otherwise joined to the plurality of end faces.

The plurality of tubes are aligned horizontally, vertically, or in a parallel helical relationship of bending, tilting, twisting, and deflection.

The tube is curved, at least partially twisted and inclined, and at least partially wrapped and twisted, and is adapted to form at least a portion of a helix in a unitary cylindrical structure having a cylindrical shape. The fins are curved, at least partially twisted and inclined, and at least partially wrapped and twisted, and are adapted to form at least a portion of a helix in a unitary cylindrical structure having a cylindrical shape.

In some embodiments, the tube has a curved middle portion and end portions, and the fins on at least one side of the tube are formed slightly concave with the central portions of the fins being inwardly offset from the outer portions of the fins. The fins on the other side of the tube are slightly raised with the central portions of the fins being offset outwardly from the exterior of the fins.

The present invention provides a method of extruding a wide and thick tube having channels therein, machining a central portion of the tube to remove material from the spaced portions from the central portion to form fins traversing the tube. The method provides a thinner central portion of the fin, leaving a head portion at the end of the tube, and having an angular or circular pattern at the tube thickness transition point. The tubes are arranged parallel to each other and are connected at thicker portions of adjacent tubes. The machined ends of the joined terminal head portions form end faces. Some of the end faces have outward protrusions extending around the channel. Some end plates have openings for receiving outward protrusions. The end plate is then attached to the end face, and in some embodiments, the end plate is attached to the protrusion.

The outward protrusions extend through the end plates and conform to the thickness of the end plates, and the engagement of the end surfaces and protrusions, if any, is by friction stir welding or hybrid friction diffusion welding.

When the end plates are joined to the protrusions by brazing, the outward protrusions extend through and beyond the end plates. The engagement of the end plates with the end faces is achieved by welding.

In one form, the method of the present invention bends the tube longitudinally after forming the thinner central portion with fins, bends the thinner curved tubular central portion, and bends the thicker curved tubular ends. The protrusions on the end faces are curved and the curved openings on the end plates accommodate the curved protrusions. The end plates are welded to the end faces and welded or brazed to the protrusions.

In another form, the method of the present invention bends the tube longitudinally after forming the thinner central portion with fins, bends the thinner curved tubular central portion, and bends the thicker curved tubular end portions. The protrusions of the end faces are curved, and the curved inner peripheral ring and outer Zhou Huanjie receive the curved protrusions. The inner and outer peripheral rings Zhou Huanhan are attached to the end faces and are welded or brazed to the protrusions.

These and further and other objects and features of the present invention are apparent in the present disclosure, including the above and ongoing written specification, the claims and the accompanying drawings.

Drawings

Fig. 1 shows a tube extrusion with microchannels.

Fig. 2 shows the fabrication of vertical fins by cutting away the material.

FIG. 3A illustrates the manufacture of angled fins by cutting away material and thereby forming integral finned tubes having a square pattern at tube thickness transition points.

FIG. 3B illustrates the manufacture of angled fins by cutting away material and thereby forming integral finned tubes having an angled pattern at tube thickness transition points.

FIG. 3C illustrates the manufacture of angled fins by cutting away the material and thereby forming integral finned tubes having a circular pattern at the tube thickness transition points.

Figure 4 shows the extrusion of a tube with a single port.

FIG. 5 illustrates the extrusion of the tube shown in FIG. 4 after cutting of the material and formation of vertical fins.

Fig. 6 shows the extrusion after the material has been cut away to form the angled fins.

Fig. 7 shows the horizontal arrangement of tubes between flat vertical header connector plates.

Fig. 8 shows the vertical arrangement of tubes between flat horizontal header connector plates.

Figure 9 shows the tubes arranged in a cylindrical shape between flat annular head plates.

Fig. 10 shows a curved tube in a cylindrical arrangement.

Fig. 11 shows a bent, twisted, skewed, helically arranged tube with beveled ends.

Figure 12 shows the joining of adjacent pipe ends by friction stir welding or hybrid friction diffusion bonding.

Figure 13 shows machining a protrusion on a tube end.

Fig. 14 shows a flat header connector plate with openings for receiving the tube end projections.

Figure 15 shows an engaged tube end with a protrusion.

Figure 16 shows a tube end with protrusions friction welded into the plate.

Fig. 17A and 17B show the flattened end at an angle relative to the bevel of the tube.

Fig. 18 shows the connection of flat angled ends.

Fig. 19A and 19B illustrate machining the flat ends of the connection to form the protrusions.

Fig. 20A and 20B show a flat annular plate with openings for receiving the protrusions.

Fig. 21A and 21B illustrate the attachment of the end projections into a flat annular plate by friction welding.

Fig. 22 shows a tube with a larger end.

Figure 23 shows the machining of protrusions for brazing on the tube ends.

Fig. 24 shows a flat header connector plate for receiving a machined end having a protrusion.

Fig. 25 shows a tube with a larger end and a protrusion ready to be mounted on and within the header connector plate.

Fig. 26 shows the brazing and ends in the plate after inserting the protrusions through the plate.

Fig. 27 shows a brazed assembly compared to fusion welding.

Fig. 28 shows fusion welding compared to the brazing in fig. 26 and 27.

Fig. 29A shows a flattening step of fig. 17A, 17B, and 18.

Fig. 29B shows an embodiment in the form of a bent, inclined, deflected and twisted tube, wherein the plurality of tubes are in a helical cylindrical arrangement without machining.

Figure 30 shows the inner and outer machined peripheral portions of the pipe ends that have been welded.

Fig. 31 shows a spiral coil assembly having machined upper and bottom perimeters for connecting respective rings.

Fig. 32 shows an end ring attached to a head portion and a weld zone.

Fig. 33A and 33B show upper and lower solid state coil polished flat surfaces for further attachment to a header tank or container.

Figures 34 to 38 show the various steps of forming and joining the tube ends, respectively.

Detailed Description

Fig. 1 shows a tube extrusion with microchannels. Solid extrusion 10 has a plurality of through ports or channels 11 and angled sides 13 with side connecting walls 15.

Fig. 2 shows the fabrication of vertical membranes by cutting away the material. The material portion 17 has been removed to leave the vertical fins 19. The resulting tube 20 has a relatively small intermediate portion 21 and a large end portion 23.

Figure 4 shows the extrusion of a tube with a single port. The solid extrusion block 40 cut from the continuous extrusion has a single central port or channel 41, sloped side walls 43 and laterally extending side connecting walls 45.

FIG. 5 illustrates the extrusion of the tube shown in FIG. 4 after cutting of the material and formation of vertical fins. The portion 47 extending across the extrusion has been removed to leave a vertical fin 49 extending across the resulting tube 50. The tube 50 has a larger end 33 surrounding a smaller middle portion 51.

Fig. 6 shows the extension after the material has been cut away to form the angled fins. Material has been removed from the portion 67 of the solid extrusion 40 to leave fins 69 at an angle to the dimensions of the formed tube 70.

Fig. 7 shows the tube being arranged horizontally with a flat vertical head plate. The tube 50 has a larger end 53 connected to a vertical mounting plate 80 which in turn is connected to a header tank, container, housing and cover to form a head chamber (not shown).

Fig. 8 shows the vertical arrangement of the tubes with a flat horizontal head plate. The vertically disposed tube 50 has a larger end 53 connected to a horizontal mounting plate 82 that is connected to the head chamber.

Fig. 9 shows arranging the tubes in a circle with a flat circular head plate. The vertically disposed tube 50 has a larger end 53 connected to upper and lower annular mounting plates 84 that are connected to the head chamber.

Fig. 10 shows a curved tube in a circular arrangement. The vertically disposed curved tube 90 has a thinner curved tubular central portion 91 and thicker curved end portions 93. Curved openings 97 are present in the upper annular mounting plate 95 and the lower annular mounting plate 95.

Fig. 11 shows a bent, twisted, skewed, helically arranged tube with beveled ends. The twisted skewed coil 100 has a similarly shaped larger end 103. The smaller intermediate portion 101 of the tube 100 has a continuous curved, twisted, skewed and spiral shape of the remainder of the tube 100. The outer head ring 105 is flat for connection to a head container.

Figure 12 shows the joining of adjacent pipe ends by friction stir welding or hybrid friction diffusion bonding. The larger ends 53 of the tube 50 are joined 110 together by friction stir welding (FWS) or Hybrid Friction Diffusion Bonding (HFDB) 112.

Figure 13 shows machining a protrusion on a tube end. The material 121 is removed from the end 125 of the larger end 53 of the tube 50 that has been connected 110 to leave behind the protrusion 127.

Figure 14 shows a flat plate with openings for tube end protrusions.

Figure 15 shows an engaged tube end with a protrusion.

The plate 130 has an opening 137 to receive and retain the protrusion 127 from the end 125.

Figure 16 shows a tube end with protrusions friction welded into the plate. The end 129 of the projection is friction welded 139 to the edge of the opening 137 in the plate. The welding is done on the cavity facing side 131 of the plate.

Figure 17A shows a single tube in the shape of a bend, twist, skew and spiral. Tube 100 is aligned and a portion of end 103 is removed such that end 107 is at an angle to the tube and aligned in parallel in the opposite end plate.

In fig. 17B, each tube 100, which is bent, twisted, deflected and helically formed, has enlarged ends 103 and fins 101. The enlarged ends will be cut or machined to flatten them horizontally.

Fig. 18 shows the connection of flat angled ends. The aligned angled end faces 109 of the wide end portion 103 of the tube 101 are friction welded 140 so that the complete cylinders of the welded tube ends 103 are joined together.

Fig. 19A and 19B illustrate the flat ends of the machined connection. As shown in the two figures, a portion of material 141 is removed from the welded together ends to provide protrusions 145. The angled removal of a portion of the end and the protrusion surrounding the opening of the channel in the tube provides a larger communication opening 146 that reduces the refrigerant pressure drop.

Fig. 20A and 20B illustrate a ring having an opening for receiving a protrusion. The flat ring 150 has an opening 155 to receive the protrusion 145.

Figures 21A and 21B illustrate the attachment of the end projections within the ring by friction welding. The inner edge 157 of the opening 155 and the end edge 147 of the projection 145 are friction welded 159 to the container side 151 of the connecting flat ring 150.

Fig. 22-27 illustrate the connection of the tube and header connector plates by brazing as compared to welding in fig. 28.

Fig. 22 shows a tube with an enlarged end. The tube 200 is formed with a larger end 203 and a relatively thinner central portion 201. Fins may be formed in the central portion by removing material from the extruded tube.

Figure 23 shows the machining of protrusions for brazing on the tube ends. The portion 204 is removed from the end to leave a protrusion 205 extending from the surface 207.

Fig. 24 shows a flat plate for receiving a machined end.

Fig. 25 shows brazing tubes on and in the plate.

The header connector plate 210 has an opening 215 to receive the protrusion 205 at the larger end 203 of the tube 200.

Fig. 26 shows the protrusions 205 extending beyond the head-container side 211 of the head connector plate after insertion of the protrusions into the ring and ending in the ring. Brazing is continuous between the surface 207, the protrusion 205, the complementary outer surface 217 and the surface of the opening 215.

Fig. 27 shows a brazed assembly compared to fusion welding.

Fig. 28 shows fusion welding compared with brazing.

The protrusion 209 of the protrusion 205 as shown in fig. 26 and 27 is necessary in order to prevent the filler material from moving and entering the micro port of the tube.

Friction Stir Welding (FSW) or Hybrid Friction Diffusion Bonding (HFDB) does not require the protrusion 225 to extend beyond the container side 231 of the head web 230.

In one embodiment of the invention, the tube is made without protrusions in the end face. The step of machining the end face to create the protrusion by removing material from the end face is avoided.

Fig. 29A shows the flattening step of fig. 17A, 17B and 18. Tube 100 is aligned and a portion of end 103 is removed such that end 107 is at an angle to the tube and aligned in parallel in the opposite end plate. Each twisted, skewed and helically curved tube 100 has enlarged ends 103 and fins 101. The aligned angled end faces 109 of the wide ends 103 of the tubes 101 are friction welded 140 so that the complete cylinders of welded tube ends 103 are joined together.

Fig. 29B shows an embodiment in the form of a bent, inclined, deflected and twisted tube 300 in the form of a helical tubular cylindrical arrangement 350, as shown in fig. 11, 17A, 17B and 2 IB. The head portion 333 is shown without machining and flattening.

Fig. 30 shows a machined inner periphery 442 and a machined outer periphery 444. The weld area 440 is shown between machined peripheral areas 442 and 444 of the flat head 446.

Fig. 31 shows a helical coil arrangement 600 of a bent, twisted, skewed and inclined tube 400 having machined inner circumferences 450 and 451, machined outer circumferences 452 and 454, and their respective upper and lower connection end rings 462 and 474 and 476.

Fig. 32 shows end rings 462, 464, 474 and 476 connected to head portions 480 and 481, respectively, upper weld areas 482 between adjacent upper heads 480, and upper peripheral weld areas 484 and 486 between upper end rings 462 and 464 to upper heads 480. The outer region 478 is shown extending outwardly from the lower attached head 481.

Fig. 33A and 33B illustrate a welded solid spiral coil assembly 700 having a reworked and/or polished upper surface 500 and lower surface 502, respectively, for further connection to a coil header or container.

Figures 34 to 38 illustrate by way of illustration and reference the formation and connection of pipe ends by the following steps: clamping and flattening the head, welding adjacent heads in areas spaced from the channels, machining the head surface, using the head end plates and polishing the ends of the solid structure.

Although the present invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention, which is defined in the appended claims.

Claims

1. An apparatus, comprising:

a plurality of heat exchanger tubes, each of said heat exchanger tubes itself having:

the central portion of the sheet is relatively thin,

a relatively thick head portion, said head portion being located on an end of said relatively thin central portion,

a fin extending outwardly from the central portion,

an end face located on an end of the head portion remote from the central portion, an

At least one passage extending through the heat exchanger tube,

wherein each of the heat exchanger tubes is extruded to have a thickness of the head portion and to have the at least one channel extending through the heat exchanger tube, and wherein material is removed from sides of the heat exchanger tube in spaced apart sections of the central portion, leaving the fins, and

wherein a plurality of said heat exchanger tubes are arranged adjacent to each other in a tight press fit between said head portions of said heat exchanger tubes.

2. The device of claim 1, further comprising a gradual transition between the relatively thin central portion and the relatively thick head portion.

3. The apparatus of claim 1, wherein the heat exchanger tube is longitudinally curved.

4. The apparatus of claim 1, wherein the heat exchanger tubes are inclined, twisted and skewed.

5. The apparatus of claim 4, wherein the fins are disposed at an angle relative to a longitudinal direction of the heat exchanger tubes.

6. The device of claim 1, wherein the ends of the head portion are flattened by cutting or machining away the ends of the head portion, and wherein the flattened ends are joined.

7. The device of claim 6, wherein the head ring is tightly disposed on the inner and outer peripheral surfaces of the flat end and is connected to the flat end by friction stir welding.

8. The device of claim 7, wherein the end of the head portion is connected by friction welding at a location remote from an area surrounding the opening of the at least one channel in the end of the head portion.

9. The apparatus of claim 7, wherein the flat connection end of the head portion of the heat exchanger tube and the head ring are polished and ready for use as a heat exchanger.

10. The apparatus of claim 5, further comprising a plurality of tubes arranged adjacent to one another in a close press fit between the head portions of the heat exchanger tubes, and wherein the ends of the heat exchanger tubes are flattened by machining or cutting and by further machining flattened end projections of the ends, and a continuous flat end surface is formed around the projections on the ends of the heat exchanger tubes.

11. The device of claim 10, further comprising a panel having an opening that receives the protrusion connected to the planar end surface by welding.

12. The device of claim 11, wherein the protrusion extends through and beyond the opening in the panel, the opening in the panel and the protrusion being sealed by brazing.

13. A method, comprising: forming a heat exchanger tube by extruding a relatively thick flat tube having at least one relatively thin channel extending therethrough; machining or ablating spaced apart portions in a central portion leaving a relatively thin central portion with spaced apart fins extending across the heat exchanger tubes and a relatively thick head portion at an end of the heat exchanger tubes, the opening of the channel being at an end of the head portion, and the method further comprising: closely arranging a plurality of tubes together; and pressing the head portions together in a tight press fit between the head portions; and holds the head portions together.

14. The method of claim 13, further comprising first bending the tube.

15. The method of claim 13, further comprising: first forming the fins at an angle to the central portion; and bending, tilting, deflecting and twisting the heat exchanger tubes prior to pressing the head portions together; flattening the ends of the heat exchanger tubes by cutting or machining the ends of the heat exchanger tubes; closely positioning a ring around the flattened ends of the heat exchanger tubes; joining the ring and the flattened ends by friction welding and joining adjacent ends of the heat exchanger tubes by friction welding, leaving the area surrounding the channels unwelded; and polishing the connected ends of the heat exchanger tubes and the connected end surfaces of the rings.

16. The method of claim 13, further comprising: first forming the fins at an angle to the flattened tube; and bending, tilting, deflecting and twisting the heat exchanger tubes prior to pressing the head portions together; flattening the ends of the heat exchanger tubes by cutting or machining the ends of the heat exchanger tubes into an integral flat surface; further machining the ends of the heat exchanger tubes to form and leave a protrusion of tubing around the opening of the channel at the ends of the heat exchanger tubes, and leaving an end face of the head portion around the protrusion; providing an end plate having an opening for receiving the projection; the end plate is placed on the end face and friction welded to the end face.

17. The method of claim 16, further comprising friction welding the opening in the end plate to a side of the protrusion.

18. The method of claim 16, further comprising extending the protrusion through the opening in the end plate and brazing the protrusion to the opening in the end plate.

19. An apparatus comprising a heat exchanger having a plurality of identical integral coils formed of extruded flat tubes having channels and extruded to have thicknesses of opposed rear head portions, opposed spaced apart side portions removed from the central portion leaving angled fins on the relatively thin central portion and retaining relatively thick head portions at the ends of the heat exchanger tubes, the heat exchanger tubes being inclined, skewed and twisted and having aligned central portions and head portions pressed together in a tight fit, the head portions having machined flat end faces and being joined by welding between adjacent end faces with the welded areas spaced from the areas surrounding the heat exchanger tubes and the end faces polished.