EP3130876A1 - Heat exchanger - Google Patents

Abstract

The invention relates to a heat exchanger with a tube bundle (2) in a tube (1) and with inclined to the axis of the heat exchanger arranged discs (12, 13), the deflection surfaces meander around the fluidic heat transfer medium through the tube (2) conduct. The discs (12, 13) also have the task of holding the tubes of the tube bundle (2) together and prevent their vibration. There are large and small disks (12, 13) are provided, wherein the outer periphery of the large disks (12) comprises the tube bundle (2) and in each large disk (12) is a central opening (14). Small disks (13) have holes (20, 21) for inner inner tubes of the tube bundle (2), wherein the small discs (13) penetrate the central openings (14) of two adjacent large discs (12) and the outer edges of the small discs (13) abut the inner edges of the central openings (14) in the large disks (12) pointwise. This results in a compact and quickly produced framework for the tube bundle, with which an effective guidance of the heat carrier is ensured by the tube.

Description

The invention relates to heat exchangers having a tube bundle having outer and inner tubes, which tube is arranged in a tube, and having a plurality of transverse struts which hold the tubes of the tube bundle together and deflection surfaces, cross struts of a first type being arranged in the tube bundle, that the deflection surfaces are rectilinearly oblique to the longitudinal axis of the tube bundle, and the transverse struts of a second type are arranged in the tube bundle, that their deflection also rectified obliquely to the longitudinal axis of the tube bundle, but crossing to the cross struts of the first type.

Such a heat exchanger is z. B. in the EP 1 067 352 A1 described. Each cross brace consists of several web plates whose surfaces form deflection surfaces and which are pushed between the tubes of the tube bundle, whereby a lattice-like structure with a plurality of intersecting deflection surfaces is formed. Due to the intersecting arrangement of the individual web plates, the web plates of the cross struts of the first type but spaced from each other by the web plates of the cross braces of the second type and vice versa, so that the deflection of each cross member is not a closed surface.

In addition, the installation of such heat exchanger with existing webs of cross-webs is very expensive, since a plurality of web plates must be arranged side by side for a deflection, which must be pushed individually onto the tube bundle.

The invention is therefore based on the object to improve the steering of the fluid flowing through the tube in terms of increased heat transfer and to simplify the assembly of the heat exchanger.

To solve the problem, the invention provides that the cross struts of the first type of large disks are formed with holes for lying in the peripheral edge of the tube bundle outer tubes and with a central opening, wherein the outer periphery of each large disk comprises the tube bundle, and that the cross struts of the second kind are formed by small disks with holes for the inner inner tubes of the tube bundle, each small disc penetrates the central opening of at least one large disk.

Preferably, the dimensions of the small disks and the large disks are chosen so that the outer edges of the small disks pointwise opposite to the inner edges of the central openings in the large disks.

According to this arrangement, a plurality of individual web plates are no longer used to form the deflection surface in a plane, but discs which form a deflection surface in a plane, wherein at least the large disks comprise the entire tube bundle and receive the outer tubes of the tube bundle in whole or in part. The small disks, which receive the inner tubes in whole or in part, lie in the central openings of the large disks and are held pointwise therein, so that a stable, the tube bundle cohesive structure is formed.

In order to increase the cohesion between the disks, the dimensions of the small disks and the large disks can be selected so that the diameter of the small disks is greater than the diameter of the central openings, and that the inner edges of the large disks each have recesses with an edge extending in the radial direction. At this edge, the small disc lays down.

It can also be thought to divide the large disks, the small disks are recorded between the dividing edge.

The large disks and the small disks each form flat deflection surfaces, which are directed against each other. Since the discs each have a closed surface, the deflection surfaces are closed, so that the flow guidance is improved.

The construction of a heat exchanger is relatively simple: It alternately large and small disks are pushed onto the tube bundle. This is done relatively quickly, since only one disc is required for each plane and not several multi-wall plates as are required in the prior art (see above).
The inclinations of the large and small disks are directed opposite. Their inclination lines include an inclination angle with the longitudinal axis of the tube.

The flow steering is particularly effective when the area of the central opening of a large disk is 40-60% of the area of the area enclosed by the outer periphery of the large disk. Since the small disks - as explained below - have a surface area which is substantially equal to the surface area of the central opening, the oppositely inclined deflection surfaces are equally weighted by the selected area ratio.

The angle of inclination is preferably between 20 ° and 70 ° or between 30 ° and 60 °.

Optimum flow conditions are achieved when the angle of inclination is between 40 ° and 50 °. In this case, large and small disks include an angle of 80 ° and 100 °.

In order not to create straight paths through the tube, which are not affected by the discs, the outer peripheral shape of the small discs is to a scale congruent with the inner peripheral shape of the central openings. This has the further advantage that the small slices can be generated as a section of the large disks, which simultaneously creates the central opening in the large windows. Due to cutting losses, the small disc is a little smaller than the central opening.

The small disks have a smaller extent in the direction of a minor axis than in the direction of a main axis perpendicular thereto, the main axis extending in the direction of the inclination of the small disks.

It is further provided that the large disks each have an outer circumference which is mirror-symmetrical to the main axis, and the central openings in the large disks have an inner circumference, which also extends mirror-symmetrically to the main axis, wherein the main axes of the outer and inner circumference in a longitudinal axis of the Tubus receiving vertical plane and run in the direction of the inclination.

Typically, the large disks have an elliptical outer circumference, while the same axis central openings have an elliptical or a polygonal inner circumference in the large disks.

In this case, located in the outer areas of the large disks, which comprise the central opening, a plurality of holes through which the outer tubes of the tube bundle are passed. On the inner circumference of the central opening and on the outer circumference of the small disks are corresponding recesses, which also receive inner tubes of the tube bundle lying further inside. The small disks mainly have holes for the inner tubes lying inside the tube bundle.

From the above-mentioned prior art is also known to arrange the deflection surfaces in sections about the tube axis rotated by an azimuth angle. In order to achieve an even better mixing of the fluid in the tube, the discs are arranged in groups, wherein the inclination line of the discs of the second group are offset from the inclination line of the discs of the first group by an azimuth angle of 90 °.

When the adjacent tubes of the tube bundle are arranged in a triangle, on the one hand large and small discs of a first group are required whose principal axes lie in a vertical plane parallel to a connecting line of two adjacent tubes of the triangle, and large and small discs of a second group whose Major axes lie in a vertical plane, in turn, is a connecting line of two adjacent tubes of the triangle.

From large disks of the first group and the associated small disks, a main package and from large disks of the second group and the associated small disks a follow-up package is formed, with major and minor packages - alternately follow one another in the longitudinal direction of the tube bundle.

In the case of the main and secondary packages, the starting and end disks are each cut in such a way that the packages end in a frontal plane which runs perpendicular to the longitudinal axis of the tube bundle.

To facilitate disassembly, support rods can be provided, which penetrate the discs and are designed as tie rods.

Fig. 1

den prinzipiellen Aufbau eines erfindungsgemäßen Wärmeüberträgers mit einem Tubus und einem darin angeordneten Rohrbündel, dessen Rohre von Querstreben zusammengehalten werden,

Fig. 2

eine perspektivische Darstellung eines Hauptpaketes, das sich aus Querstreben in Form von Klein- und Großscheiben zusammensetzt,

Fig. 3

eine Draufsicht auf eine Großscheibe und eine Kleinscheibe für ein Hauptpaket gemäß Fig. 2,

Fig. 4

eine perspektivische Darstellung eines aus Großscheiben und Kleinscheiben bestehenden Folgepaketes, und

Fig. 5

eine Draufsicht auf eine Großscheibe und eine Kleinscheibe für ein Folgepaket gemäß Fig. 4.

In the following, the invention will be explained in more detail with reference to an embodiment. To show:

Fig. 1

the basic structure of a heat exchanger according to the invention with a tube and a tube bundle arranged therein, the tubes of which are held together by transverse struts,

Fig. 2

a perspective view of a main package, which consists of cross struts in the form of small and large disks,

Fig. 3

a plan view of a large disk and a small disk for a main package according to Fig. 2 .

Fig. 4

a perspective view of a consisting of large disks and small disks follower package, and

Fig. 5

a plan view of a large disk and a small disk according to a follower package Fig. 4 ,

According to the Fig. 1 a heat exchanger consists of a tube 1, in which a tube bundle 2 is held together by a plurality of transverse struts 3. The cross struts 3 also serve to guide a fluid through the tube. 1

In the tubes of the tube bundle 2, it may be z. B. to be nested tubes, where a heat transfer medium in the form of a fluid via an end flange 4 is supplied to a head 5 of the tube 1, which is discharged via a side flange 6 on the head 5.

The supply and removal of the heat carrier takes place via opposite lateral flanges 7, 8 on the tube 1, which are located just below the head 5.

The tube bundle 2 is held together by main packages and follow-up packages, wherein a main package 11 in the Fig. 2 is shown. This package 11 consists of a plurality of mutually parallel and inclined with respect to the longitudinal axis of the tube large disks 12 and a plurality of mutually parallel and inclined relative to the longitudinal axis of the tube small disks 13. The surfaces of the discs 12, 13 form deflection surfaces for a flowing through the tube 1 fluid ,

The inclination of the discs 12, 13 is defined in each case by an inclination line which lies in the respective disc and which encloses a minimum angle, the inclination angle, with the longitudinal axis of the tube. The angular position of the projection of the inclination line in the polar plane is the azimuth angle. The angular distance between the azimuth angle of the inclination lines of the large disks 12 and the inclination lines of the small disks 13 is 180 ° in this embodiment. The inclination lines of the large disks 12 and the small disks 13 at the same time form their main axes 16 (see Fig. 3 ), which lie in a common plane, on which the discs 12, 13 are each perpendicular.

The large disks 12 further each have a central opening 14 in which the small disks 13 are inserted. Large disks 12 and small disks 13 are thus nested.

Furthermore, the large disks 12 and the small disks 13 have a plurality of holes 15, through which the tubes of the tube bundle 2 are passed accurately.

The large disks 12 and the small disks 13 are congruent with each other. The dimensions of a large disk 12 and a small disk 13 result from the Fig. 3 , which shows a plan view of the discs 12, 13 in the direction of the tube bundle 2, so that the large disc appears circular. In fact, both have an elliptical shape, as in the Fig. 2 can be seen. The central openings 14 are substantially congruent with the small disks 13. This allows, in each case a small disk 13 from a large disk 12 z. B. cut out by means of a laser beam. Because of the resulting cutting losses, the small disks 13 are slightly smaller than the large disks and are therefore congruent with the central openings 14 only up to a scaling factor.

The elliptical shape shown here is one way to perform the large and small slices. But also polygonal or round shapes are possible. Fig. 3 also does not recognize the inclination of the discs 12, 13. These are - like that Fig. 2 it can be seen - directed against each other, so that the two discs 12, 13 at an angle of z. B. cut 90 °. Other angles are also possible.

The lengths of the discs 12, 13 are, measured in their major axes 16, about the same size. The widths of the small disks 13 are, based on their minor axes 17, which are perpendicular to the main axes 16, approximately smaller by half than the corresponding widths of the large disks 12th

In this embodiment, the tube bundle has a hexagonal outer contour, wherein adjacent tubes are arranged in the corners of an equilateral triangle. This corresponds to a so-called triangular division of 60 °.

Thus, the holes 18 for the corner tubes of a hexagon arranged tube bundle 2 on the minor axis 17 of the large disk 12. The large disk 12 includes further holes 19 for pipes in the outer region of the tube bundle 2, while tubes inside the tube bundle 2 of holes 20 in the Small disc 13 can be recorded.

Some tubes run through the edges of the small disc 13 and the inner edge of the large disc. Here are recesses 22a, 22b, in the plan view - like the Fig. 3 shows - seemingly form a closed hole.

The arrangement of the tubes in the hexagon is to be understood as an example. It is a shape in which adjacent tubes lie in the corners of an isosceles triangle. The result of this is that when the disks 12, 13 slope in the direction of a line of the triangle, the holes in the disks 12, 13 must be arranged differently than in the case of disks whose main axis lies in the direction of a bisector of the triangle (as in FIG FIGS. 2 and 3 shown). The same applies to an arrangement of the tubes on the corners of an equilateral right triangle with two equal sides.

The previously described discs 12, 13 according to FIGS. 2 and 3 are arranged so that the azimuth angle of their inclination lines is 0 ° or 180 °. They thus form a main package.

In order to influence the flow of the fluid in the tube 1 so that the heat transfer is improved, follows in the tube on a main package 11, a follower package 26, the discs 12, 13 are oriented so that the azimuth angle of their inclination lines at 90 ° and 270 ° lie.

The 4 and 5 show such a follow-up package 26. This corresponds to a main package with the difference that there are 12 holes 27 for tubes of the tube bundle 2 on the minor axes 17 of the large disks, which are all on the perpendicular bisector of the isosceles triangles, so as shown in the Fig. 5 lie in one edge of the hexagon of the tube bundle 2. Furthermore, located on the major axis of the small discs 13 holes 28 which are adjacent in the isosceles triangle.

There are also tube bundles are known in which the tubes are arranged in a square. In this case, if the tube mirror is identical for both axes, identical discs can be used for main and follower packages, since the distribution of the tubes in the tube bundle 2 is identical in each case at azimuth angles offset by 90 ° from one another.

To produce a secured by cross struts 3 tube bundle 2 are first the large and small discs 12, 13 of a main package alternately pushed onto the tube bundle 2, wherein the outer edges of the small plates 13, the inner edges of the central openings 14 of the large discs 12 pointwise opposite, the discs 12, 13 can be welded together at these locations.

In order to achieve a change in the orientation of the inclination, a change to slices of the auxiliary package is made after one or more large disks, and then change back to a main package. Since the individual packages require a straight front end, the large and small disks that form the end pieces of a package 11, 26, along a cutting edge 29, as the Fig. 2 and 4 show, shortened.

The deflection of the obliquely and angularly arranged discs 12, 13 cause the fluid is meandering passed through the tube 2, whereby a good heat transfer is ensured.

By bundling the tubes by means of the discs 12, 13 also vibrations of the tubes of the tube bundle are suppressed. Furthermore, a uniform flow of the tubes over the entire range is achieved by a constant angle of inclination relative to the tube bundle axis, so that a uniform heat transfer is achieved.

The use of discs prevents dead corners and angles and there is a uniform but slight pressure drop across the cross-section and length of the tube.

By changing the spacing of the holes for the tubes, the angle of inclination of the discs 12, 13 can be adapted to the respective requirements.

The principle can basically be used for all shell and tube heat exchangers such as liquid / liquid, gas / gas, gas / liquid and liquid / gas.

The pipes can be both smooth and ribbed. As already explained above, field tubes can be used.

LIST OF REFERENCE NUMBERS

1

tube

2

tube bundle

3

crossbars

4

frontal flange

5

head

6

lateral flange

7

lateral flange

8th

lateral flange

11

main package

12

large slices

13

small slices

14

central opening

15

holes

16

main axis

17

minor axis

18

Hole for corner pipe

19

more holes

20

holes

21

Hole for central tube

22a

recesses

22b

recesses

26

follow package

27

hole

28

hole

29

cutting edge

Claims (14)

Heat exchanger having an outer and inner tubes having tube bundle (2) which is arranged in a tube (1), and with a plurality of transverse struts, which hold together the tubes of the tube bundle (2) and deflection surfaces, wherein cross struts of a first type such in Tube bundles are arranged, that their deflection rectilinear obliquely to the longitudinal axis of the tube bundle (2), and the web plates of a second type are arranged in the tube bundle, that their deflection also rectified obliquely to the longitudinal axis of the tube bundle (2), but crossing to the cross struts of run first type, characterized in that the transverse struts of the first type of large disks (12) with holes (18, 19) for in the peripheral edge of the tube bundle (2) lying outer tubes and are formed with a central opening, wherein the outer periphery of each large disk (12 ) comprises the tube bundle (2), and that the transverse struts of the second type of small discs (1 3) with holes (20, 21) for inner inner tubes of the tube bundle (2) are formed, wherein each small disc (13) penetrates the central openings (14) of at least one large disc (12). Heat exchanger according to claim 1, characterized in that the dimensions of the small disks and the large disks are selected so that the outer edges of the small disks (13) the inner edges of the central openings (14) in the large disks (12) pointwise opposite. Heat exchanger according to claim 1, characterized in that the dimensions of the small disks and the large disks are selected so that the diameter of the small disks is greater than the diameter of the central openings, and that the inner edges of the large disks each have recesses with a radially extending edge. Heat exchanger according to one of the preceding claims, characterized in that the surface area of the central opening of a large disk (12) is 40-60% of the area of the surface enclosed by the outer periphery of the large disk (12). Heat exchanger according to one of the preceding claims, characterized in that the angle of the inclination lines of large and small disks (12, 13) to the longitudinal axis of the tube is between 20 ° and 70 °. Heat exchanger according to claim 5, characterized in that the angle of the inclination lines of large and small disks (12, 13) to Längsache of the tube (1) between 30 ° and 60 ° and preferably between 40 ° and 50 °. Heat exchanger according to one of the preceding claims, characterized in that the outer peripheral shape of the small disks (13) is congruent with the inner peripheral shape of the central openings (14) except for a scaling. Heat exchanger according to claim 7, characterized in that the small disks (13) have a smaller extent in the direction of a minor axis (17) than in the direction of a main axis (16) perpendicular thereto. Heat exchanger according to claim 8, characterized in that the large disks (12) each have an outer periphery which is mirror-symmetrical to the main axis (16), and the central openings (14) in the large disks (12) have an inner circumference, which is also mirror-symmetrical to the Main axis (16) extends, wherein the main axes (16) of the outer and inner periphery lie in a longitudinal axis of the tube (1) receiving the vertical plane. Heat exchanger according to claim 9, characterized in that the large disks (12) have an elliptical outer periphery, while the same axial central openings (14) in the large disks (12) also have an elliptical or polygonal inner circumference. Heat exchanger according to one of the preceding claims, characterized in that adjacent tubes of the tube bundle (2) are arranged in a triangle, and that large and small discs (12, 13) of a first group exist whose main axes (16) in a vertical plane with the parallel to a connecting line of two adjacent tubes of the triangle, and large and small discs (12, 13) of a second group exist whose major axes (16) lie in a vertical plane, in turn, is a connecting line of two adjacent tubes of the triangle. Heat exchanger according to claim 11, characterized in that from large disks (12) of the first group and the associated small disks (13) a main package (11) and of large disks (12) of the second group and the associated small disks (13) a follower package (26) is formed, wherein main and follower packages (11, 26) follow one another alternately in the longitudinal direction of the tube bundle (2). Heat exchanger according to claim 12, characterized in that in the main and follower packages (11, 26) each of the starting and end disks are capped such that the packages (11, 26) terminate in a frontal plane perpendicular to the longitudinal axis of the tube bundle ( 2) runs. Heat exchanger according to one of the preceding claims, characterized in that the discs (12, 13) are penetrated by one or more support rods, which are designed as tie rods.

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