EP0451507A1 - Heat-exchanger - Google Patents

Abstract

Heat exchangers, in which the tubes (2) are retained by radial expansion in openings of the tube base (4), are provided in the region of the expanded tube ends with inserted sleeves (7) which guarantee seating of the tube ends in the tube base (4). Insertion of the individual sleeves (7) is complicated. It is proposed to deep-draw all the sleeves (7) in one piece from a common strip, and to provide each sleeve (7) with a flange projecting at approximately right angles, and to adjoin it to the material of the strip via the flange by means of punched, bow-like webs. This configuration substantially simplifies assembly. Use for heat exchangers in motor vehicles. <IMAGE>

Description

The invention relates to a heat exchanger with a plurality of tubes which are held with at least one end in assigned openings in a tube sheet, sleeves being pushed into the tube ends in the region of the tube base and pressed non-positively against the tubes and the openings in the tube sheet.

Heat exchangers of this type are known (DE 35 45 554 A1 - P 7454). In these known designs, a tube-bottom connection is provided, in which the sleeves inserted into the tube ends press the tube firmly against the opening in the tube base after it has expanded, so that a liquid-tight connection is produced. Since the sleeve is largely inside the tube, no parts of the sleeve protrude beyond the tube-bottom connection. Pipe-to-floor connections of this type require the individual sleeves to be inserted into the pipe ends before they are expanded. This is relatively expensive.

The invention has for its object to design a heat exchanger of the type mentioned so that the insertion of the sleeves is significantly simplified, so that the manufacture of the heat exchanger is easier.

To solve this problem it is provided in a heat exchanger of the type mentioned that at least part of the Sleeves is arranged on a common sleeve bottom and each adapted to the position of the openings and the tubes in the tube sheet. This configuration results in an assembly part with which a plurality of sleeves can be brought to the assigned locations in a single operation and inserted in a simple manner into the pipe ends. The manufacture of heat exchangers with inserted sleeves, which ensure a particularly good tightness of the pipe-floor connection, is considerably simplified. The sleeves can either be pressed against the tubes and the openings in the tube sheet by widening or by axially pressing them in excess (sleeve diameter is slightly larger than the tube diameter).

Advantageous developments of the invention are characterized in the subclaims.

The features of claim 2 have the advantage that a strip can be produced in a particularly simple manner, for example by deep-drawing in the desired manner, and can then also be handled particularly easily during assembly. According to claim 3, the sleeves - as is known per se - be provided with a circumferential flange running outward at one end, which facilitates the pressing of the sleeves into the pipe ends and secures the position of the sleeves. In a further development of the invention, these flanges are connected to one another in a common plane through the sleeve base to form the strip. As a result, the running-in resistance can be reduced, in particular if the sleeve infeed is more rounded. The features of claims 4 and 5 bring the essential advantage that despite the arrangement in a common strip-like sleeve bottom, all sleeves are largely individually held so that they can adapt to the associated pipe ends during assembly within the scope of existing tolerances . On the other hand, this embodiment also has the advantage that material from the Flange area of the sleeve can flow to expand the sleeve, which would not be possible or not easily possible if the flange were connected all around to the bottom of the sleeve. Otherwise the bottom of the case would warp. Finally, there is the advantage that the sleeve base acts as a flow guide surface and thus causes a lower flow resistance of the heat exchanger.

Due to the configuration according to claim 5, all sleeves are held elastically on the sleeve bottom. They can be individually adapted and deformed without this leading to adverse effects on the strip-shaped sleeve base due to the flexibility of the stirrups connected to the flanges.

In the case of circular sleeves, which will be the rule, the features of claim 6 are advantageous. It is of course also possible to design the sleeves oval or in the shape of flat tubes if this should be necessary.

The sleeves can be deep-drawn in a simple manner, as previously indicated, with the associated strip-shaped sleeve bottom. The webs for holding the flanges can be punched out or cut. This ensures simple and economical production. The sleeves and sleeve bottom can be made of a metal sheet, but also of plastic.

Fig. 1

eine schematische Draufsicht auf den Rohrboden eines Wärmetauschers gemäß der Erfindung - in Richtung des Pfeiles I der Fig. 2 gesehen -, wobei nur ein Teil des Rohrbodens gezeigt ist,

Fig. 2

den Schnitt durch den Rohrboden der Fig. 1 längs der Linie II-II in vergrößertem Maßstab,

Fig. 3a

eine nochmals vergrößerte Teildarstellung des Bereichs III in Fig. 2,

Fig. 3b

die Darstellung gemäß Fig. 3a, jedoch vor dem Aufweitvorgang zum Verpressen der Rohre im Rohrboden,

Fig. 4a

eine Darstellung ähnlich Fig. 3a, jedoch für eine andere Art des Herstellvorganges,

Fig. 4b

die Darstellung ähnlich Fig. 3b für die Ausführung nach Fig. 4a,

Fig. 5

eine schematische Darstellung einer Konfektioniermöglichkeit eines gemäß der Erfindung hergestellten streifenförmigen Hülsenbodens mit mehreren Hülsen, der zur Anpassung an entsprechende Rohrböden - wie in den Fig. 12 und 13 gezeigt - in einzelne Teile zerschnitten werden muß,

Fig. 6

eine andere Möglichkeit des Zerteilens eines gemäß der Erfindung ausgebildeten streifenförmigen Hülsenbodens, wobei mit Schrägschnitten gemäß Fig. 5 gearbeitet wird,

Fig. 7 bis 10

Trennmöglichkeiten für den streifenförmigen Hülsenboden, die mit abgestuften Trennschnitten arbeiten,

Fig. 11

eine Möglichkeit, mit zick-zack-förmigen Trennschnitten zu arbeiten,

Fig. 12a und 12b

die schematischen Darstellungen von Rohrböden mit jeweils unterschiedlichen Hülsenbodenteilen,

Fig. 13

eine Darstellung ähnlich Fig. 12a oder 12b, jedoch bei einer anderen Aufteilung und Anordnung von zwei Hülsenbodenstreifen,

Fig. 14

eine vergrößerte Detaildarstellung des Bereiches XIV eines der streifenförmigen Hülsenbodenstücke der Fig. 13 und

Fig.15

den Schnitt durch Fig. 14 längs der Linie XV-XV.

In the drawing, the invention is illustrated using exemplary embodiments and is explained in the following. Show it:

Fig. 1

2 shows a schematic plan view of the tube sheet of a heat exchanger according to the invention, viewed in the direction of arrow I in FIG. 2, only part of the tube sheet being shown,

Fig. 2

the section through the tube sheet of FIG. 1 along the line II-II on an enlarged scale,

Fig. 3a

2 shows a further enlarged partial view of area III in FIG. 2,

Fig. 3b

3a, but before the expansion process for pressing the tubes in the tube sheet,

Fig. 4a

a representation similar to Fig. 3a, but for a different type of manufacturing process,

Fig. 4b

3b for the embodiment according to FIG. 4a,

Fig. 5

FIG. 2 shows a schematic representation of a possibility of assembling a strip-shaped sleeve base produced according to the invention with a plurality of sleeves which, as shown in FIGS. 12 and 13, has to be cut into individual parts in order to adapt to corresponding tube sheets,

Fig. 6

another possibility of dividing a strip-shaped sleeve base designed according to the invention, using bevel cuts according to FIG. 5,

7 to 10

Separation options for the strip-shaped sleeve base, which work with graduated separating cuts,

Fig. 11

one way to work with zigzag cuts,

12a and 12b

the schematic representations of tube sheets with different sleeve base parts,

Fig. 13

12a or 12b, but with a different division and arrangement of two sleeve bottom strips,

Fig. 14

an enlarged detail view of the area XIV one of the strip-shaped sleeve bottom pieces of FIGS. 13 and

Fig. 15

the section through Fig. 14 along the line XV-XV.

1 and 2 schematically show a heat exchanger (1) which, in a manner known per se, has a finned tube block which consists of a plurality of tubes (2) arranged parallel to one another and of fins arranged in a lamella-like manner between these tubes and perpendicular to the tube axes (3) exists. The tube ends shown in FIG. 2 are pressed tightly into a tube sheet (4) which, as shown in FIG. 1, is provided with a plurality of openings (5) (see FIG. 3b) into which the tubes ( 2) pushed in with their ends and, as will be explained with reference to FIGS. 3a, 3b and 4a, 4b, are fastened by radial widening. The tube sheet (4) is then provided in a known manner with a water tank (6) through which one of the heat exchange means, preferably a liquid, can be fed to the finned tube block, which in turn is perpendicular to the tube axes and across the spaces between the fins (3). can be flowed through with a second heat exchange medium, preferably air. Heat exchangers of this type are used, for example, as radiators or coolers in motor vehicles.

As can also be seen from FIGS. 1, 2 and 3a, sleeves (7) are inserted into the open ends of the tubes (2) and all of them sleeves inserted into the tube ends of the tubes (2) are part of a sleeve base (8) designed in the form of a strip, with which all sleeves (7) can be handled together and fed to the tube ends. For this purpose, the sleeves (7) are attached to the sleeve base (8) so that their relative position to one another is matched to the arrangement of the tubes (2) or the openings (5) in the tube base (4). The sleeves (7) can therefore be assigned to the tube sheet (4) and the tubes (2) together, or at least partially together, as will be explained later.

Fig. 3a and Fig. 3b show that this is done first in such a way (Fig. 3b) that the tubes (2) each from one side in the associated and the opening (5) forming, designed as passages (9) of the tube sheet (4) are inserted, the tubes (2) also being provided with the loosely pushed-on ribs (3) in a known manner. Once this has been done, the sleeve base (8) is fed to the tube sheet (4) in such a way that the sleeves (7) are pushed into the open ends of the tubes (2) with appropriate play. 14 will be explained that all sleeves (7) are provided with a way to compensate for tolerances. 3b is reached, the tube (2) is first expanded with two expanding tools so that the ribs (3) are firmly seated in it. Then the sleeve (7) is widened with a second tool so that it is pressed with the tube (2) outwards against the collar (9) of the tube sheet. In this way, the tube sits tightly in the tube sheet.

4a and 4b show a modification of the manufacturing process insofar as here the insertion process according to FIG. 4b is carried out analogously, as is explained with reference to FIG. 3b. The only difference in production is that the tube sheet area with the sleeve (7) is one and the same tool, is expanded, for example, with an expansion ball to the same extent as the tube (2) in the region of the ribs (3). The widened inside diameter (d _i ) of the sleeve (7) therefore corresponds to the widened pipe diameter (d _R ).

It is clear from this description that the manufacturing process of a heat exchanger according to the invention can be simplified by using the strip-shaped sleeve base (8) on which many sleeves are arranged accordingly. It is namely not necessary to assign the plurality of sleeves to the corresponding pipe ends either by hand or by means of likewise complex assembly devices. It is also advantageous that the sleeves (7) receive a stop area through the sleeve bottom, which prevents the sleeves from being pushed in too far or from being inserted insufficiently. All sleeves can be inserted flush with their flange corresponding to the sleeve bottom (8) in a very simple manner. The flange of the sleeves (7) also serves as a stop for the ends of the tubes (2) inserted from the other side.

The sleeves (7) can be produced in a very simple manner, for example in the deep-drawing process, from a sheet metal strip unwound from a coil. It is also possible to produce the base of the sleeve with the sleeves from plastic by injection molding. This strip must then be subdivided into sleeve base pieces (8 ') according to FIG. 5, the separating cuts (10) each taking place obliquely to the longitudinal direction of the strip (8) in the exemplary embodiment of FIG. 5, at an angle which is adapted to the angle is, which results from the arrangement of the sleeves (7) in the strip (8). Dash-dotted lines indicate the connecting line (11) between the axes of two adjacent sleeves (7). The separating cut (10) is made at the same angle to the longitudinal edges of the strip (8). 6 shows a modification of the arrangement of the separating cuts (10) insofar as the separating cuts here (10, 10 ') each take place at a changing angle, so that, as in FIG. 5, strips (8') in parallelepiped form do not arise, but strips (8 '') with mutually identical trapezoidal shapes.

As will be explained subsequently with reference to FIG. 12b, the separation of sleeve base pieces (8 ') or (8' ') by bevel cuts is often not sufficient to fit the sleeve base or the sleeve base pieces into the space which will later be restricted by the water tank (6) to enable. 7, 8 and 10 therefore provide step-like separating cuts (12) which, however, can alternate with symmetrical separating cuts (12 ') according to FIG. 8, so that different shapes of sleeve bottom strip pieces (80 and 80') arise. Fig. 9 brings a modification in that here separating cuts (12 ') are also provided in step form, but here are determined by the arrangement of a recess (13) with which a sleeve is cut out of the strip-shaped sleeve bottom (8) during the separating cut . Such strip shapes (80 '') can also be used to manufacture the heat exchanger as required. 10 and 11 show different separating cuts (14 and 15), which also enable a different strip shape (81 and 81 ') with the same design of the sleeve bottom strip (8). It would also be possible to make the separating cuts in a rounded shape instead of a stepped shape.

12a and 12b are intended to make the meaning and purpose of this different separating cut arrangement clear. 12a and 12b show the outline of the water tank (6), the inner wall (6a and 6a ') of which should surround the outermost pipe pairs as closely as possible. The on the left side (Fig. 12a) above the tube sheet (4) arranged sleeve bottom strip part (80 ') - which can be made according to FIG. 7 or also according to FIG. 8 - fits the left edge (6a) of the Water box well on and runs, which is not shown in detail, to the right edge of the water box (6). Its length therefore corresponds to the length of the tube sheet and the water tank. In Fig. 12b, however, the sleeve bottom strip (8 ') is separated so that a tube-free separation space can remain in the middle of the water box, which, for example, which will be explained later, can be used to arrange a partition between two tube bundles. The sleeve bottom strip part (8 ') inserted on the right half (FIG. 12b), for example produced according to FIG. 5, extends in the example with its lower right edge (16) into the area of the wall (6a') of the water tank (6) . The strip part (8 ') shown is therefore not suitable for the water tank (6) shown.

FIG. 13 shows a solution in which sleeve base strip parts (80 ″) are used in the production method according to FIG. 9. There are no pipes in the middle because, for example, to produce heat exchangers with separate controls for the driver and front passenger, a partition (25) runs in the water tank (6) in this area, which is indicated by dashed lines. It can be seen that the separating cuts (12 ') run here in such a way that the sleeve base strip parts (80' ') adapt to the interior of the water tank and that the recesses (13) formed thereby are used to form the intermediate space for arranging the partition wall (25) .

14 shows that each sleeve (7) with the flange (17) running at one end approximately at right angles to the sleeve axis (18) does not pass directly into the strip-shaped material of the sleeve bottom strip (8). Rather, each flange (17) of a sleeve (7) is connected to the strip part (8) only at three webs (19) which are arranged at equal intervals on the circumference, but is otherwise separated from it by approximately crescent-shaped incisions (20). These incisions (20) for their part adjoin the bracket (21) in the exemplary embodiment, which as Narrow, flexible connecting bridges are only connected at their ends to the plane of the sleeve base strip (8), but are otherwise separated from them by entire narrow crescent-like incisions (22). Two of the brackets (21) therefore open at a common connection point (23) in the plane of the strip-like sleeve base (8).

Instead of the described embodiment, it would also be possible in a simpler way not to punch out incisions (20) in the shape of a crescent moon, but only to make circular-arc-shaped incisions along the dividing lines (30 and 30 ') indicated on the lower right sleeve (7) in FIG. 14, so that the same effect is achieved even then. The sleeves are freely movable when pulling the sleeve during the manufacture of the sleeve base, during insertion and during deformation. Fig. 14 represents
then the installed state of the sleeve strip (8) in the expanded and deformed condition of the sleeves (7) and sleeve flanges (17), in which the crescent-shaped recesses (22) and the then - indicated by dashed lines - also crescent-shaped recesses (20 ') ) have formed adjacent to the separating cuts (30, 30 ').

As is clear from FIGS. 14 and 15, this configuration means that each individual sleeve is largely freely movable on the common strip (8). It can therefore easily adapt to tolerance deviations when inserted into the pipe ends. Even in the case of deformation due to the expansion process, as described with reference to FIGS. 3a, 3b, 4a, 4b, the individual suspension of the sleeves (7) has the advantage that material can flow from the area of the flange (17) without that the area of the outer sleeve bottom (8) is affected. Discarding or deforming the connecting parts of the sleeve base (8) between the individual sleeves is thus excluded. A flawless This ensures production with which the necessary tightness of the pipe-floor connection is achieved.

Claims (10)

Heat exchanger with a plurality of tubes (2) which are held with at least one end in assigned openings (5), in particular passages (9) of a tube sheet (4), sleeves (7) being pushed into the tube ends in the region of the tube sheet and non-positively against the Pipes and the openings in the tube sheet are pressed, characterized in that at least some of the sleeves (7) are adapted to a common sleeve base (8) and in each case to the position of the openings (5) and the tubes (2) in the tube sheet (4) is arranged. Heat exchanger according to claim 1, characterized in that the sleeve base is a part (8 ', 80, 81) of a strip provided with the sleeves (7) which is separated by a separating cut (10, 12, 14, 15). Heat exchanger according to claims 1 and 2, characterized in that the sleeves (7) are attached to the strip with flanges (17) lying in the plane of the strip (8). Heat exchanger according to claim 3, characterized in that each flange (17) of a sleeve (7) is connected to the sleeve bottom strip (8) by narrow webs (19), each web (19) by cuts (20) from the sleeve bottom strip (8) and is separated from the neighboring footbridge. Heat exchanger according to claim 4, characterized in that three webs are provided which are uniformly distributed over the circumference of each flange (17). Heat exchanger according to claim 4, characterized in that the webs (19) are each connected to brackets (21) which are bridge-like with their two ends with the sleeve bottom strip are connected, but are separated from the material of the sleeve base strip (8) by a crescent-like incision (22). Heat exchanger according to claim 6 for sleeves (7) with a cylindrical cross section, characterized in that the incisions (20 and 22) and the bridge-like brackets (21) have at least one circular arc-shaped edge which extends approximately over 120 °. Heat exchanger according to one of claims 1 to 7, characterized in that the sleeves (7) are deep-drawn from the material of the sleeve bottom strip (8). Heat exchanger according to one of claims 1 to 8, characterized in that the incisions (20, 22) are punched out or cut from the material of the sleeve bottom strip (8). Heat exchanger according to one of claims 1 to 9, characterized in that the sleeve bottom strip (8) and the sleeves consist of metal or plastic.

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