EP0305702B1 - Heat exchanger with a finned tube arrangement - Google Patents

Description

The invention relates to a heat exchanger according to the preamble of claim 1. Such a heat exchanger is known from DE 3532493 C1. In this type of construction, a tube sheet made of plastic is connected to metal tubes in a particularly simple manner. This is done in that the free ends of the tubes, which are each combined in a known manner to form a finned tube block, are inserted into grooves in retaining lugs of the tube sheets. The pipe ends thus located in the retaining lugs are then sealed in the tube sheet in that after the tube ends have been pressed in with an expanding mandrel, both the plastic of the holding connector and the end of the tube are radially expanded. Such designs are tied to certain design specifications due to the use of the known metallic finned tube block, in which the surfaces of the fins arranged in the manner of lamellae run perpendicular to the tube axes.

As is known, the ribs which are flown by air parallel to their surfaces serve to guide the air and - because of their large surfaces - to improve the heat transfer.

It is also known to manufacture heat exchangers by fitting individual components made of plastic together (EP-A-0191956). The plastic parts used to construct such a heat exchanger are extruded. Such designs are not suitable for all purposes due to the lack of finned tube arrangement. The necessary wall thicknesses of such extruded plastic components are also relatively high, so that the heat exchangeability is impaired. This also applies to other known types of plastic heat exchanger block (DE-A-2204167), which has only fin-like spacers in the longitudinal direction of the tubes.

Finally, it is also known (DE-A-3536527) to produce a heat exchanger block for a liquid / air / heat exchanger from a one-piece injection-molded part, in particular from aluminum, the tubes of which narrow in a wedge shape to the center, so that the cores necessary for the casting after can be removed during manufacture. The tube sheets cast in one piece on both sides must also be suitably designed to remove the core. Apart from the fact that a narrowing of the flow cross-section in the tubes is unfavorable, it is only possible with such a type of production to produce certain types of heat exchanger specified by the shape. There is no way to vary the shape or size of the fin tube block.

The invention has for its object to provide a heat exchanger with a finned tube arrangement, in particular a water / air cooler for motor vehicles made of plastic, so that there is largely freedom for the construction of the heat exchanger, so that both in the form different, as well as in the performance different heat exchangers can be manufactured with the same components.

To solve this problem, the characterizing features of claim 1 are provided in a heat exchanger of the type mentioned. In contrast to the known designs, where the tube sheets are already integrally connected to the finned tube block in die casting or injection molding, according to the invention only one tube equipped with fins or uses a group of tubes, which have common fins, as a modular component, which is then connected to a tube sheet in the desired manner to the final shape. The ends of the tubes or tube groups can be connected to the associated tube sheet in a relatively simple and known manner, since both the tubes or tube groups, including their fins arranged thereon, and the tube sheet are made of plastic. Known types of connection, such as friction or laser welding, ultrasonic welding, but also gluing or mechanical joining can therefore be used to assemble the tube sheet and module component. The advantage of laser welding is that different materials can also be welded.

Since the pipes with the associated ribs are made of plastic by the injection molding process, no conical extensions of the pipes need to be provided in order to be able to remove the cores. The new modular components therefore have a uniform flow cross-section for the heat exchange media. The configuration according to the invention also ensures that the individual module components, in particular also individual tubes, can be combined with the outer edges of their ribs to form different designs of the entire heat exchanger block without the gaps influencing the flow occurring between the aligned ribs of adjacent module components.

Advantageous developments of the invention are characterized in the subclaims. The features of subclaims 2 to 5 have the advantage that, despite the use of a positive fit when the pipe ends are pressed in, no constrictions or widenings of the flow cross section have to occur in the area of the openings of the tube sheets. A uniform flow through the finned tube arrangement is therefore possible.

The features of subclaims 6 and 7 have the advantage that the flange provides a relatively large contact surface on the tube sheet, which is suitable, for example, for gluing. Due to the raised edge, the module component is stiffened.

The features of subclaims 10 to 12 offer the advantage that the air flowing through is excited to increase turbulence, which improves the heat transfer. The features of subclaims 13 to 16 outline various possibilities, by influencing the cross-section in the tubes, which can be designed in particular as flat tubes, also Improve turbulence and heat transfer from the liquid to the pipe walls.

Fig. 1

einen schematischen Längsschnitt durch einen Teil eines mit mindestens einem Modulbauteil und mit zwei damit verbundenen Rohrböden mit Wasserkästen aufgebauten Kunststoffwärmetauscher,

Fig. 2

den Schnitt durch den Wärmetauscher der Fig. 1 längs der Linie II-II,

Fig. 3

einen Wärmetauscher ähnlich Fig. 1, bei dem jedoch zur Herstellung der gleichen Baugröße wie in Fig. 1, mehrere und andere Modulbauteile verwendet sind,

Fig. 4

den Schnitt durch den Wärmetauscher der Fig. 3 längs der Linie IV-IV,

Fig. 5

eine vergrößerte Detaildarstellung des Anschlußbereiches zwischen Rohrende und Rohrboden, wie sie bei einem der Wärmetauscher der Fig. 1 und 3 vorgesehen sein kann,

Fig. 6

eine andere Anschlußmöglichkeit in einer Darstellung ähnlich Fig. 5,

Fig. 7

die schematische Darstellung eines Teilschnittes ähnlich Fig. 4, jedoch bei einer Ausführungsform, bei der die Rippen des zugeordneten Rohres Sechseckform aufweisen,

Fig. 8

eine Darstellung ähnlich Fig. 7, jedoch bei einem Modulbauteil, bei dem die Rippen Trapezform aufweisen,

Fig. 9

eine Darstellung ähnlich den Fig. 7 und 8, jedoch unter Verwendung von Flachrohren, die von Rippen mit Trapezform umgeben sind, wobei mehrere, jeweils aus einem Rohr aufgebaute Modulbauteile mit den Außenkanten ihrer Rippen zu einem mehrreihigen Rippen-Rohr-Wärmetauscher zusammengefügt sind,

Fig. 10

eine Darstellung ähnlich Fig. 9, bei der jedoch die einzelnen Modulbauteile zu einem ringförmigen Wärmetauscher zusammengesetzt werden,

Fig. 11

einen Schnitt durch eine andere Ausführungsform eines Modulbauteiles mit einem Flachrohr und mit einer rechteckigen Rippenanordnung, wobei der Innenquerschnitt des Flachrohres in besonderer Weise gestaltet ist,

Fig. 12

einen Schnitt ähnlich Fig. 11, jedoch etwas vergrößert und bei einer Ausführungsform, bei der der Innenquerschnitt anders gestaltet ist,

Fig. 13

einen Schnitt ähnlich Fig. 11 mit einem Flachrohr, das aus einem Mehrkammerquerschnitt aufgebaut ist,

Fig. 14

einen Teilschnitt ähnlich Fig. 6, jedoch bei einem Modulbauteil mit Rippen in Wellform,

Fig. 15

die Ansicht des Modulbauteiles der Fig. 14 in Richtung des Pfeiles XV,

Fig. 16

die vergrößerte Darstellung eines Teilschnittes durch eine Rippe der Fig. 14, bei der Turbulenz erzeugende Spitzen an den Rippen vorgesehen sind und

Fig. 17

eine schematische Darstellung einer Ausführungsform, bei der die Rohre des Wärmetauschers aus mehreren Teilrohrstücken zusammengesetzt sind.

The invention is illustrated in the drawing using exemplary embodiments and is explained below. Show it:

Fig. 1

2 shows a schematic longitudinal section through part of a plastic heat exchanger constructed with at least one module component and with two tube plates with water boxes connected thereto,

Fig. 2

the section through the heat exchanger of FIG. 1 along the line II-II,

Fig. 3

1, but in which several and other module components are used to produce the same size as in FIG. 1,

Fig. 4

the section through the heat exchanger of FIG. 3 along the line IV-IV,

Fig. 5

2 shows an enlarged detailed view of the connection area between the pipe end and the pipe base, as can be provided in one of the heat exchangers of FIGS. 1 and 3,

Fig. 6

another connection possibility in a representation similar to FIG. 5,

Fig. 7

the schematic representation of a partial section similar to FIG. 4, but in an embodiment in which the ribs of the associated tube have a hexagonal shape,

Fig. 8

a representation similar to FIG. 7, but with a Modular component in which the ribs have a trapezoidal shape,

Fig. 9

7 and 8, but using flat tubes which are surrounded by fins with a trapezoidal shape, several modular components, each made up of a tube, being joined together with the outer edges of their fins to form a multi-row finned tube heat exchanger,

Fig. 10

9 shows a representation similar to FIG. 9, but in which the individual module components are assembled to form an annular heat exchanger,

Fig. 11

3 shows a section through another embodiment of a modular component with a flat tube and with a rectangular rib arrangement, the internal cross section of the flat tube being designed in a special way,

Fig. 12

11 shows a section similar to FIG. 11, but somewhat enlarged and in an embodiment in which the inner cross section is designed differently,

Fig. 13

11 shows a section similar to FIG. 11 with a flat tube which is constructed from a multi-chamber cross section,

Fig. 14

6 shows a partial section similar to FIG. 6, but in the case of a modular component with corrugated ribs,

Fig. 15

the view of the module component of FIG. 14 in the direction of arrow XV,

Fig. 16

the enlarged view of a partial section through a rib of FIG. 14, in which turbulence-generating tips are provided on the ribs and

Fig. 17

is a schematic representation of an embodiment in which the tubes of the heat exchanger are composed of several pipe sections.

1 and 2, a part of a heat exchanger made of plastic is shown, which consists of a one-piece plastic module component (10) and from the two, each with the ends of the tubes (1 ') of this module component (10) connectable tube sheets (2 ) with water boxes (4) and (5). Tube plates (2) and water boxes (4) and (5) are also made of plastic in the embodiment.

The module component (10) of FIGS. 1 and 2 consists of 25 individual tubes (1 '), which are arranged in columns and rows at the same distance from each other and by common ribs arranged one above the other perpendicular to the tube axes (1a) ( 6 ') are firmly connected in the form of square plates. Pipes (1 ') and fins (6') form a single component, molded or molded from plastic. The ends (9) of the tubes (1 ') protrude from this component and are connected to the tube sheets (2) in a manner yet to be explained (see e.g. FIG. 5). In the embodiment of FIGS. 1 and 3, the upper tube sheet (2) is part of a water box (4) connected to it in one piece. The lower tube sheet (2) is separate from the water tank (5), which can be connected to the tube sheet (2) in a known manner. As shown in FIG. 2, a further module component (10A) or other module components of the same type as the module component (10) can be connected to this module component (10), the connection of the module components (10, 10A) to each other being a common one Tube plate (2) takes over, which is designed according to the desired final shape of the heat exchanger.

3 and 4 show a modification of the heat exchanger of FIGS. 1 and 2 insofar as here the module component (1) in each case consists only of a tube (1) with fins (6) arranged in one piece thereon. As shown in FIG. 4, these individual module components (1), ie the tubes (1) with the associated fins (6), are assembled to form a heat exchanger block similar to FIG. 2 in that the outer edges of the fins (6) aligned with one another abut each other are arranged and the individual tubes (1) are received with their ends in common tube plates (2).

Fig. 5 shows a first possibility of joining a tube sheet (2) with the ends (9) of the tubes (1) of the embodiment of Figs. 3 and 4. In this embodiment, the tube ends (9) are expanded and have a diameter (i.e. _E ), which is larger than the inner diameter (d) of the tube (1) itself. These extended tube ends (9) are pressed into a circumferential plug-in groove (11) in an edge (8) of the tube sheet (2), which is designed like a sleeve and is provided in the region of the opening (7) of the tube sheet (2) for the tube (1). The configuration is such that the width of the plug-in groove (11) corresponds to the thickness of the wall of the pipe end (9) and that the depth (h) of the plug-in groove (11) corresponds to the length (1) of the enlarged area of the pipe end (9) is adjusted. It is also ensured that the distance between the wall of the plug-in groove (11) facing the opening (7) and the inner wall of the opening (7), which has the diameter (D _R ), the difference in the diameters (d _E - d) corresponds. In such an embodiment, after the pipe end (9) is pressed into the plug-in groove (11) as far as it will go, there will be no change in diameter inside the pipe (1) because the enlarged area of the pipe end (9) is separated from the sleeve-like inner part (30). the edge (8) is filled. Since both the tube sheet (2) including the rim (8) and the tube (1) with the ribs (6) arranged in one piece thereon are made of plastic, this form-fitting joining can result in a very tight connection between the tube sheet (2) and the tube ( 1) can be achieved. Of course it is also possible to use additional glue Connect and seal between the tube sheet (2) and tube (1) if necessary. Tight connections can also be achieved by ultrasonic or laser welding, the plug-in groove (11) only having to be designed for preassembly.

Another type of connection between the tube sheet (2) and tube (1) is shown in Fig. 6. Here, the tube ends (9) have an outwardly projecting flange (12) which extends perpendicular to the tube axis (1a) and is provided with a circumferential rib (13) which projects in the direction of the tube axis (1a). The tube sheet (2) is provided in the region of the opening (7) with an edge (8 ') which has a counter surface (31) which runs parallel to the surface (32) of the flange (12) and which can be used for the tube (1) using the flange (12) by means of an adhesive connection with the tube sheet (2). It would also be possible to make the connection using ultrasound or a laser. In the embodiment shown, the tightness of the connection is additionally increased by the rib (13); the rib (13) also has the advantage of stiffening the pipe end (9) and stiffening the finished heat exchanger.

7 to 10 show possibilities for designing the outer contour of the ribs (6) of a modular component, consisting of a tube or a flat tube, differently than shown in FIG. 4. 7 shows the shape of a hexagon (14) for the outer contour of the ribs (6) of the module component (1). These ribs can therefore be aligned with their outer edges (34) and (35) on adjacent hexagonal rib contours (14A) and (14B). The honeycomb shape of the ribs (6) allows largely any type of heat exchanger to be produced.

This also applies if the ribs (6) of the modular component (1) have the shape of a trapezoid (15) which, as in Fig. 8 shown, with other adjacent fins in a trapezoidal shape (15E) can be put together to form a row of tubes, which of course can be combined with further rows to form a finned tube block which is held together by corresponding tube sheets.

9 and 10 finally show the possibility of using flat tubes (1 ') with an approximately oval cross-section instead of tubes (1) with a circular cross-section, which can also be surrounded by ribs with a trapezoidal shape (15). Here too, two or more rows of heat exchanger blocks can be constructed, for example by joining adjacent trapezoidal shapes (15A and 15B). As shown in Fig. 10, it is also possible to build circular heat exchangers with the trapezoidal shape (15) and the correspondingly created trapezoidal shapes (15C) and (15D) of the fins of flat tubes (1 '). Of course, it is also possible to provide the hexagonal outer contour or the trapezoidal outer contour, as well as, for example, a uniform octagonal contour of the ribs, not only in the case of a modular component which is each constructed from a tube. Of course, the common fins (6 ') of FIG. 2 in a modular component (1'), consisting of several individual tubes, can be brought into such polygonal shapes, which can then be combined to form larger heat exchanger blocks. The invention therefore makes it possible to manufacture heat exchangers of various shapes and capacities from uniform modular plastic components. The arrangement of the fins connected in one piece with the tubes also allows the wall thickness of the tubes themselves to be chosen to be relatively small without affecting the strength. This has an advantageous effect on the heat transfer. The new modular components are preferably suitable for the construction of heat exchangers, such as those used in stationary and transient heating technology. By choosing a suitable plastic, such heat exchanger systems can also be used with corrosive and / or aggressive media.

To improve the heat transfer while maintaining stability, flat tube shapes according to FIGS. 11 to 13 can also be provided. Fig. 11 shows an embodiment in which a flat tube (1 ') is provided with approximately rectangular ribs (6). However, this flat tube has an internal cross section that has no parallel side walls (22) and (23). Rather, these inner walls (22 and 23) are provided with ribs (24) which extend parallel to the direction of flow and increase the surface area, by means of which the heat transfer can be improved. The cross-sectional shape of the flat tube (1 ') of FIG. 12 has a similar effect, where the inner walls are designed in the form of two interlocking longitudinal teeth (25) and (26), which have a zigzag slot (27) between them. leave. Such cross-sectional shapes of tubes for heat exchangers, which can be equipped with outer fins at the same time, can be produced when plastic is used as the production material. The cross-sectional shape of the flat tube (1 ') of FIG. 13, which is provided with a plurality of chambers (21) running parallel to one another, is also particularly stable. The plastic used for production can also be stiffened in a manner known per se by fillers and also improved in terms of its heat transfer. A further improvement in the thermal efficiency can be achieved by coating the surface with materials that conduct heat well, especially metals, e.g. Copper. The coating also serves as a diffusion barrier for media that can diffuse through plastic and can contribute to increasing the strength. The coating is preferably applied after all the module components have been assembled.

14 to 16 show an embodiment of the module of FIG. 3, in which a tube (1) is equipped with ribs (6) which have a wave shape. The course of the waves, ie the wave crests (18) running parallel to one another, is in each case arranged such that the crests (19) of the wave crests are respectively run perpendicular to the direction of flow (16) in which the air is carried out between the ribs (6). In the case of a water / air cooler, the water flows through the pipes (1) in the direction (28) or in the opposite direction, as indicated in FIG. 14. The ribs (6) provided in this way with profiles (17) force the air flowing through to an increased turbulence and thus to an improved heat absorption by the ribs, which in turn pass on the heat given off by the water to the pipes (1).

Fig. 16 shows one way of designing the waveform, which can be realized in the manufacture of plastic. Here, at the apex (19) of the wave crests (18) on one side of the ribs (6), inclined edges (20) against the flow direction (16) are provided, which help to promote the breaking off of the flow and the increase in turbulence. 14 and 15 is readily apparent, the demolding of the modular component of those figures is made possible by pulling a cylindrical core out of the tube (1) and pulling the mold halves in the direction of the wave crests. Since plastic is used as the manufacturing material, it is not absolutely necessary to provide conical core parts for the pipes. The plastic is still elastic during demolding and therefore also allows the demolding of cylindrical cores.

17 shows a possibility of assembling the tubes (1) themselves from several, in the exemplary embodiment from two partial tube pieces (1a, 1b). Here the upper ends of the pipe sections (1a) in the tube sheet of a water tank (4 ') and the lower ends are held in a coupling piece (3). In the coupling piece (3) sit also the upper ends of the pipe sections (1b), which open into the second water tank (5 '). This structure makes it possible to realize heat exchangers with large pipe lengths.

Claims (18)

1. Heat exchanger, consisting of a finned tube arrangement, of which the tubes (1) are supported at both ends in tube plates (2) of header tanks (4, 5) and of which the fins (6, 6′), which are in a lamellar like superposed arrangement, run at right angles to the axis (1a) of the tubes (1, 1′) and are subjected to a stream of air or the like in their longitudinal direction, the tuble plate at least being made of plastic material, characterised in that a tube (1) or a group (10) of tubes (1′) is designed in one piece with the surrounding fins (6, 6′) to form a modular component which is made of plastic material and which can be assembled with the tube plate (2) and optionally with other modular components (1A, 1B, 10A), and that the fins of the modular component (1, 10) all have the same design and, in a plan view in the direction of the tube axes (1a), have a polygonal shape suitable for the assembly of adjacent modular components.

2. Heat exchanger according to Claim 1, characterised in that the openings (7) of the tube plates (2) for the tube ends (9) are provided with edges (8) having a socket-like design.

3. Heat exchanger according to Claims 1 and 2, characterised in that on their sides facing the tube ends (9), the edges (8) of the openings (7) are provided with an encircling groove (11) for inserting the tube ends.

4. Heat exchanger according to Claim 3, characterised in that the tube ends (9) have a diameter (d_E) which is greater than the remaining tube diameter (d), and that the internal diameter (D_R) of the edges (8, 30) of the opening (7) is equal to the internal diameter (d) of the tubes (1).

5. Heat exchanger according to Claim 4, characterised in that the depth (h) of the insert groobe (11) is equal to the length (1) of the broader area of the tube end (9).

6. Heat exchanger according to Claim 1, characterised in that an outwardly directed flange (12) extending perpendicular to the tube axis (1a) is provided at the tube ends (9).

7. Heat exchanger according to Claims 6 and 3, characterised in that the flange (12) is provided, on its side directed towards the tuble plate (2), with an encircling rib (13) which can be inserted into an insert groove (11′).

8. Heat exchanger according to Claim 1, characterised in that the fins (6) have the shape of a regular hexagon (14).

9. Heat exchanger according to Claim 1, characterised in that the fins (6) have a trapezoidal shape (15).

10. Heat exchanger according to Claim 1, characterised in that the fins (6) are provided with profile sections (17) at right angles to the direction of laminar flow (16).

11. Heat exchanger according to Claim 10, characterised in that an undulatory form is provided as the profile section (17).

12. Heat exchanger according to Claim 11, characterised in that pointed edges (20) for increasing turbulence are provided at least on one side at the apex (18) of the undulation crests (19).

13. Heat exchanger according to Claim 1 and any one of the other Claims, characterised in that the tubes are in the form of flat tubes (1′).

14. Heat exchanger according to Claim 13, characterised in that the flat tubes (1′) have a cross-section with a plurality of chambers (21) running parallel to one another.

15. Heat exchanger according to Claim 13, characterised in that the flat tubes (1′) are provided, on their oppositely lying longer inner sides (22, 23), with ribs (24) which run in the direction of flow (28) and taper towards their free ends and pairs of which are arranged opposite one another.

16. Heat exchanger according to Claim 13, characterised in that the oppositely lying inner sides (22, 23) are designed in the manner of interlocking longitudinal toothing (25, 26) between which a zigzag-shaped gap (27) is formed.

17. Heat exchanger according to Claim 1, characterised in that the tubes (1) consist of tube sections (1a, 1b) which are in aligment with one another and the ends of which are retained at least partially in couplers (3).

18. Heat exchanger to Claim 1, characterised in that the modular components (1A, 1B, 10A) are coated with an advantageously heat-conductive material, particularly metal, at least in the area of the tubes (1) and fins (6, 6′).

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