FINNED TUBE AND METHOD OF MANUFACTURING THE SAME

Abstract

A finned tube having a tube main body, on the outside of which, in particular separate or integral, fins are arranged, preferably circumferentially, wherein the fins and/or the tube main body are of a multi-layer material.

Claims

1-13. (canceled)

14. A finned tube, comprising: a tube main body; and fins arranged on an outside of the body, wherein the fins and/or the tube main body are of a multi-layer material.

15. The finned tube according to claim 14, wherein the fins are separate or integral with the tube main body.

16. The finned tube according to claim 14, wherein the fins are arranged circumferentially on the tube main body.

17. The finned tube according to claim 14, wherein the fins and/or the tube main body consist of a plated material.

18. The finned tube according to claim 17, wherein the plated material covers the entire surface of the fins and/or the tube main body.

19. The finned tube according to claim 14, wherein the layers of the multi-layer material each consist of metallic material.

20. The finned tube according to claim 19, wherein the layers of the multi-layer material are inseparable.

21. The finned tube according to claim 14, wherein the multi-layer material comprises at least one layer from the group consisting of: copper, aluminum, (stainless) steel, (copper-) nickel, titanium, brass, and bronze.

22. The finned tube according to claim 14, wherein the finned tube comprises, in an area where the fins are attached to the tube main body, a melt with which a strip is fixed to the tube main body to form the fins.

23. The finned tube according to claim 22, wherein the melt is a hardened melt.

24. The finned tube according to claim 22, wherein the strip is welded to the tube main body.

25. The finned tube according to claim 22, wherein the melt does not contain any melted material of an innermost layer of the strip and/or of the tube main body.

26. The finned tube according to claim 15, wherein the fins are integral with the tube main body and the tube main body consists of the multi-layer material, wherein the integral fins are rolled out of the tube main body.

27. The finned tube according to claim 26, wherein the fins are rolled, in particular exclusively out of an outermost layer of the tube main body.

28. The finned tube according to claim 14, wherein an inner layer of the fins is in direct contact with at least one layer of the tube main body.

29. The finned tube according to claim 28, wherein the inner layer of the fins is in direct contact with an inner layer of the tube main body.

30. The finned tube according to claim 14, wherein a most thermally conductive layer of the fins is in direct contact with a most thermally conductive layer of the tube main body.

31. A method for producing a finned tube, comprising the steps of: providing a multi-layer material; and attaching or forming fins on a tube main body using the multi-layer material.

32. The method according to claim 31, wherein the multi-layer material is plated.

33. The method according to claim 31, further including fixing a strip to an outside of the tube main body to form the fins, wherein the strip and/or the tube main body consist of multi-layer material.

34. The method according to claim 33, including welding the strip to the outside of the tube main body.

35. The method according to claim 33, wherein the fins are formed helically.

36. The method according to claim 31, wherein the tube main body consists of the multi-layer material, the method including rolling the fins out of the tube main body.

37. The method according to claim 36, including rolling the fins out of an outermost layer of the tube main body.

38. The method according to claim 31, further comprising an initial step of: selecting at least two starting materials for the multi-layer material depending on requirements resulting from a desired use of the finned tube being produced.

Description

[0113] Further advantages of the invention are apparent from the dependent claims not cited and from the following description of the exemplary embodiments shown in the figures, in which:

[0114] FIG. 1 shows, in a very schematic side view, the process of producing the multi-layer material (as used in finned tubes according to the invention),

[0115] FIG. 2 shows, in a very schematic cross-sectional view, approximately in line with view arrow II in FIG. 1, a first configuration of a multi-layer material, for example usable for the production of fins of a finned tube according to the invention,

[0116] FIG. 3 shows, in a view approximately according to FIG. 2, a cross-section of a second exemplary embodiment of a multi-layer material, for example for the production of a tube main body,

[0117] FIG. 4 shows, in a view approximately according to FIG. 3, a further exemplary embodiment of a multi-layer material in a “core-lay” configuration with enclosed core, in particular for the production of fins,

[0118] FIG. 5 shows, in a view approximately according to FIG. 4, a further exemplary embodiment of a multi-layer material,

[0119] FIG. 6 shows, in a very schematic, partially cut side view of a finned tube according to the invention in a straight or still unshaped embodiment,

[0120] FIG. 7 shows a likewise schematic, enlarged detail of the finned tube according to the invention showing a single fin,

[0121] FIG. 8 shows the portion according to circle VIII in FIG. 7 in enlarged view with the addition of a further, not yet welded fin, to the left of the already attached fin shown in FIG. 7, with a fin in “core-lay” configuration,

[0122] FIG. 9 shows, in a view approximately as shown according to FIG. 8, another exemplary embodiment with a fin plated over its entire area,

[0123] FIG. 10 shows, in a view approximately according to FIG. 9, a further exemplary embodiment according to which the fin is immersed in a molten bath of the tube main body for the purpose of attachment,

[0124] FIG. 11 shows, in a view according to FIG. 10, a method approximately according to FIG. 10, with the difference that the outermost layer of the tube is thinner and is completely melted,

[0125] FIG. 12 shows, in a very schematic view, approximately according to view arrow XII in FIG. 13, the cross-section through a tube main body made of multi-layer material for the production of a finned tube according to the invention, and

[0126] FIG. 13 shows the tube main body according to FIG. 12 in a schematic, sectional side view with additional representation of a disc set for working out integral fins from the tube main body.

[0127] Exemplary embodiments of the invention are described in the following figure description, also with reference to the drawings. For the sake of clarity, identical or comparable parts or elements or regions are denoted by the same reference signs, sometimes with the addition of small letters or apostrophes—even where different exemplary embodiments are concerned.

[0128] FIG. 1 first shows, in a very schematic representation, a method for producing a multi-layer material 8 which is used for producing the fins 13 and/or the tube main body 12 of a finned tube 10 according to the invention and shown in FIG. 6.

[0129] As shown in FIG. 1, three materials 1, 2, 3 are used for this purpose, which can, for example, initially be in the form of continuous material, preferably in the form of a supply 4 (for example in the form of a coil from which they can then be removed).

[0130] The materials 1, 2, 3 are available, by way of example, in the form of strips, in particular in the form of metallic strips, that is to say in the form of strips made of metal and/or metal alloys.

[0131] For the sake of simplicity, we will assume that the material 1 is stainless steel, the material 3 is (the same) stainless steel and the material 2 is copper. However, this is only to be understood as an example. In fact, any configuration of different materials suitable for the production of finned tube components is possible.

[0132] In particular, the material 1 and the material 3 do not have to be the same. In principle, completely different materials can be selected here, depending on the desired application.

[0133] In any case, the present strips made of materials 1, 2, 3 (of course, only two materials or more than three materials, in particular in the form of strips, may be present) are fed to a cladding stand 5, which may, for example, provide a plurality of rolls 6.

[0134] The strip-like materials 1, 2, 3 are rolled together between the rolls 6, if necessary, with the addition of heat. Optionally, a subsequent heat treatment, which is not shown in more detail, is also possible in an area marked with the reference sign 7 in FIG. 1, which can further improve the adhesive strength between the individual materials 1, 2, 3.

[0135] In this way, a strip-like, multi-layer material 8 is produced, the cross-section 8a of which, shown in FIG. 2 for the present first exemplary embodiment (corresponding to the configuration in FIG. 1), turns out to be three-layered, i.e. in a configuration with three layers.

[0136] According to FIG. 2, the plating is what is known as full-surface plating, in which the materials 1, 2, 3 of the individual layers each lie on top of each other over the entire area. In other words, each material layer extends over the entire width b of the material 8.

[0137] The thicknesses d of the individual layers of material can be different here, wherein the respective output strips of a supply 4 in essence determine the final layer thickness (in the present exemplary embodiment according to FIG. 2, the output strips 1 and 3 according to FIG. 1 were correspondingly thicker than the middle strip 2).

[0138] Alternatively, a layer can also be produced from a plurality of strips of the same material.

[0139] FIG. 2 shows a three-layer strip with two outer (identical) material layers 1 and 3 and a middle material layer 2.

[0140] For example, the material layers 1 and 3 can be stainless steel layers, and the material layer 2 can be a copper layer.

[0141] Another configuration of a multi-layer material 8 is shown in FIG. 3: This multi-layer material 8b consists of only two layers of different materials, namely a first material layer 1 and a second material layer 2′.

[0142] These layers only have identical layer thicknesses d.sub.1 and d.sub.2, which can of course also differ from each other.

[0143] For example, the layer 1 can be stainless steel and the layer 2′ can be copper. Such a configuration, shown in FIG. 3, can be suitable for example for working out/forming a tube main body of a finned tube according to the invention from such a material.

[0144] FIG. 4 then shows a configuration of a multi-layer material 8c, which is more typically used to form fins.

[0145] Similarly to FIG. 2, FIG. 4 shows a configuration in which a layer of an identical material 1, 3 is present at the top and bottom (for example stainless steel) and a core of a different material 2″ (for example copper) is present in the middle.

[0146] In contrast to the arrangement according to FIG. 2, the configuration according to FIG. 4 shows a so-called “core-lay” configuration or an enclosed core 2″, in particular in the sense that the upper and lower layers 1 and 3 merge into each other at the sides (with respect to the width b) and thus enclose the middle layer 2″. In this case, the strips 1 and 3 used for production would simply be slightly wider than the strip 2.

[0147] Such a configuration, similarly to the configuration according to FIG. 2, can be used particularly well for forming fins in finned tubes.

[0148] Merely by way of example, FIG. 5 then shows a further configuration of a multi-layer material 8d, which consists of five layers merely by way of example. Also merely by way of example, the structure here is symmetrical orthogonally to the width b or perpendicularly to the side b, with identical outer layers 1′ and 3′, identical adjoining layers 9 and 9′ and a middle layer 2′″ made of a third material (or else of the material of the outer layers 1′ and 3′). Many configurations are conceivable here and FIG. 5 is only intended to indicate that the invention is not limited to two or three layers.

[0149] FIG. 6 then shows an already completed finned tube 10, which has basically been produced from two separate pieces: First, a tube main body 12 is provided, which is designed as a straight round tube. A multi-layer strip 13′ is wound helically around the main body 12 and is welded to the tube main body 12. The strip 13′ thus forms an endless fin arrangement 13 of fins 17 (wherein the strip 13′ of course actually has a finite, fixed length; in other words, the fins 17 are continuous).

[0150] As shown in FIG. 6, the strip 13′ leaves the ends 14 and 15 of the tube main body 12 free and is welded to the surface 16 of the tube main body 12. As already mentioned, and in particular visible at the left end 15 of the tube main body 12 in the partially transparent illustration, the tube main body 12 is hollow with a first, inner wall thickness d.sub.1, an outer wall thickness d.sub.2 (thus a total wall thickness d.sub.1+d.sub.2) and a diameter D. The fin arrangement 13 has a fin height h.

[0151] The mean distance a between two adjacent fins 17 can be chosen according to requirements. For example, a mean distance a of up to six millimeters can be achieved (or a pitch of less than five fins/inch). In particular, a pitch of between 5 to 13 fins/inch can be achieved (corresponding to a mean distance a of between about 2 mm and 5 mm). However, this is to be understood only as an example.

[0152] The method according to the invention can also be used with a variable spacing of the fins on the tube (or with a variable pitch on a tube). For this purpose, the feed speed and/or the rotation speed of the tube can be varied. The largest portions a between adjacent fins can, for example, assume the values given above. In principle, however, the distances can also be much smaller than specified above, regardless of whether variable spacing is provided or not.

[0153] The production process for the finned tube 10 according to the invention will now be explained in more detail with reference to FIGS. 7 to 11.

[0154] FIG. 7 first shows a purely schematic, partially cut representation of an enlarged individual representation of an already welded fin 17. The fin 17 is welded to the tube surface 16 in the area shown.

[0155] FIG. 8 shows said fin 17 in its right-hand display area in the already welded state. FIG. 3 shows the already solidified melt 18 in the contact area 19 between the tube main body 12 and the strip 13. The melt 18 consists proportionally of material from both the tube main body 12 and the strip 13′ or the fin 17 (on its underside).

[0156] The fin 17 is approximately rectangular in cross-section for this purpose.

[0157] The fin 17 shown on the right side in FIG. 8 is located further forward in the finning direction B (as an already fixed fin) than a fin 17′ also shown in FIG. 8. In FIG. 8, this fin 17′ is welded straight in the contact area 19 (which is substantially L-shaped due to the straight tube surface 16 and the straight side edge 20 of the fin 17′).

[0158] For this purpose, a fiber laser beam 21 of a fiber laser not shown in FIG. 8 falls on the contact area 19 at an angle δ, in particular a small angle θ. The fiber laser beam 21 irradiates both material of the strip 13′ or the fin 17′ and material of the tube main body 12, in particular on the surface 16 of the latter.

[0159] Since the fin 17 is located in front of the fin 17′ in the finning direction B, the left portion according to FIG. 8 represents, so to speak, the state of welding of a portion of the strip and the right side according to FIG. 8 then represents the finished, welded-on state of a portion of the strip. Further portions of the strip would naturally follow in particular in the finning direction B (and thus would already be welded) with a defined fin pitch.

[0160] With reference to FIGS. 6 to 8, it should be noted at this juncture that the finned tube 10 shown here has both a tube main body 12 and fins 17 made of a multi-layer material.

[0161] This is to be understood as merely exemplary. In other exemplary embodiments, which are also considered to be disclosed, the tube main body 12 can, for example, only consist of single-layer material (wherein it would then have to be imagined, for example, that the layer of thickness d.sub.1 provided with the reference sign 2′ has been omitted).

[0162] Alternatively, a multi-layer tube main body 12 could be used, but conventional fins 17 made of only one material (in which case the cross-section of the fins 17, 17′ in FIG. 8 would then of course look different, namely without a core).

[0163] However, the present exemplary embodiment shows a finned tube 10 in which both the tube main body 12 and the fins 17 consist of multi-layer material:

[0164] For example, FIG. 6 shows that the tube main body 12 is made of a multi-layer material, as shown in cross-section in FIG. 3, for example.

[0165] Such a material according to FIG. 3 can be further processed into a tube main body by bending/rolling a corresponding strip, for example, and then attaching it to itself (for example welding it) or the like. However, the invention is not intended to be limited to this. All other conceivable possibilities for producing a tube main body from a multi-layer material are included.

[0166] FIG. 6 shows in any case that the tube main body 12 hereby has an outer layer of a first material 1 and an inner layer of a second material 2′. For example, the outer layer 1 can be stainless steel, and the inner layer 2′ can be copper or aluminum or the like.

[0167] Thus, in this exemplary embodiment, the tube main body 12 consists of plated material, wherein other multi-layer materials are also to be considered as disclosed.

[0168] As shown in FIG. 8, the fins 17 or 17′ also consist of a multi-layer material, in particular one with a cross-section according to FIG. 4.

[0169] FIG. 8 thus shows that the fins 17 and 17′ have a layer 1 and 3 respectively of a first material on the outside and an inner layer or core of a second material 2″.

[0170] The core 2″ can, for example, be a material with very good thermal conductivity, such as copper. The material of the outer layers 1 and 3 is typically a material with very good corrosion resistance (such as stainless steel).

[0171] FIG. 8 shows a configuration with an enclosed core (i.e. a “core-lay” configuration), which has the advantage in the present case, for example, that the inner layer 2″ is not also melted during the welding process shown in FIG. 8 and thus its material does not enter the melt 18. This is precisely what may be desired in certain applications.

[0172] In other applications, the opposite effect may be desired: for example, FIG. 9 shows a variation of the exemplary embodiment shown in FIG. 8, in which the fins 17 and 17′ do not have the configuration according to FIG. 4, but a configuration according to FIG. 2, in which the layer 2 of the multi-layer material 8a has the same width as the layers surrounding it (so that no “core-lay” configuration is present, but a full-surface plating).

[0173] This results, in particular in that straight material of the central layer 2 is now also included in the melt 18′. Such a design could have the advantage that the heat from the fins can be better transferred into the tube main body 12.

[0174] FIG. 10 shows a third exemplary embodiment for separate fins 17 or 17′, which are fixed to a tube main body 12. This exemplary embodiment differs from the exemplary embodiments according to FIGS. 8 and 9 in that here, during the welding process, only material of the tube main body 12 is melted by the laser beam 21 (and thus no material of the fin 17 or of the strip 13′). After a melt 18″ has been created in this way in the tube main body 12, in particular in its outermost layer 1, the fin 17 or 17′ is simply dipped into the melt 18″, which is not yet solidified, for the purpose of fastening.

[0175] Since all this is done in very short time intervals, separate fins can be fixed on the tube main body also in this way.

[0176] Lastly, FIG. 11 shows another configuration which corresponds substantially to the configuration according to FIG. 10. In contrast to FIG. 10, however, the method according to FIG. 11 uses a tube main body 12 that has a much thinner outer layer of a first material 1.

[0177] In this sense, FIG. 11 shows that the laser beam 21 melts this layer 1 over the entire thickness d, in particular without substantially penetrating the layer 2′ underneath (however, depending on the accuracy and desire, it is also unproblematic if a small part of the layer 2′ is melted).

[0178] The method according to FIG. 11 therefore corresponds substantially to that according to FIG. 10, since here the fins 17 or 17′ are in essence not melted on.

[0179] Here, too, the fins are subsequently “dipped” into the melt 18′″.

[0180] Since the melt 18″ extends over the entire layer thickness d of the layer of the first material 1, the central layer 2 of the fin 17 can abut or come into contact with the bottom or inner layer 2′ of the tube main body 12.

[0181] For example, the layers 2 and 2′ (for the purpose of optimized heat conduction) can be made of the same material, preferably copper or aluminum.

[0182] In summary, in the embodiment according to FIG. 11, a thermal/materially consistent bridge can thus be created between the core of a fin and an inner layer of a tube main body, which further improves the thermal conductivity of the resulting fin tube.

[0183] A different method of producing a finned tube 10′ according to the invention with integral fins 17″ is then shown in FIGS. 12 and 13.

[0184] FIG. 12 here shows a cross-section of a tube main body 12′ with an inner (in particular thinner) layer of a first material 1 and an outer (in particular thicker) layer of a second material 2.

[0185] Merely by way of example, the material 1 can be stainless steel, which has a particularly good corrosion resistance to the fluid (for example water or the like) to be conducted in the interior 21 of the tube main body 12′.

[0186] The outer material 2 can be a material which is particularly suitable for the integral formation of fins, for example copper.

[0187] This is shown in FIG. 13 in a very schematic, sectional side view:

[0188] FIG. 13 illustrates in this respect that the outer layer 2 has a greater material thickness than the inner layer 1. This is particularly typical since fins 17″ are to be formed out of the outer layer 2, which requires some material thickness.

[0189] In addition, the inner layer 1 is usually made of a more valuable material and is therefore thinner for cost reasons.

[0190] In FIG. 13, a rolling tool 22 is only indicated. Any suitable rolling tool can be used which is capable of forming fins 17″ from the tube main body 12′, in particular by applying pressure to the tube main body 12′. For example, the tool 22 shown has a plurality of discs (disc sets) for this purpose.

[0191] During the rolling process, the tube main body 12′ is typically supported on a rolling mandrel not shown, wherein in particular the inner layer 1 can rest directly on said rolling mandrel.

[0192] This mandrel, which is not shown, can for example rotate about its longitudinal axis, wherein the rolling tool 22 can typically be arranged in a stationary (in particular rotational) manner.

[0193] Of particular importance in this case is that the rolling tool 22 exerts a contact pressure in the direction F on the tube main body 12′ during the forming of the fins 17″. In this process, individual fins 17″ are worked out of the tube main body 12′ or the outer layer 2.

[0194] The fins 17″ can, for example, extend circularly in a plane around the tube main body 12′ or in the form of an endless fin, i.e. substantially helically or in a helix-like manner.

[0195] Finally, it can be noted with regard to FIG. 13 that the fins 17″ according to this method thus no longer have to be arranged or welded separately or individually on the tube main body 12, but rather are worked out of the tube main body 12′ or the outer layer 2 so as to be formed from the same material and in one piece integrally therewith.

[0196] In another exemplary embodiment, not shown, the layers 1 and 2 can also be selected in such a way that material from an inner layer 1 also enters the area of the fins 17″ during the forming of the fins 17″ (these thus show both materials in cross-section). In this case, the layer 2 would have to be somewhat thinner than in the present exemplary embodiment according to FIG. 13.