DE102017210797A1 - Method for mounting a heat exchanger - Google Patents

Abstract

The invention relates to a method for mounting a heat exchanger (1) with a plurality of flat tubes (2) with convex side walls (3) and between adjacent flat tubes (2) arranged rib structures (4) which are formed in the transverse direction stiffer than the flat tubes (2), with the process steps
Alternately stacking the flat tubes (2) and the rib structures (4) to a heat exchanger block (5), the flat tubes (2) with their convex side walls (3) being in contact with the rib structures (4),
- Attachment of two parallel to the flat tubes (2) aligned side parts (6),
- Applying a permanent compressive force on the two side parts (6) and compressing the heat exchanger block (5) until the convex side walls (3) of the flat tubes (2) are at least almost flat and create a flat surface of rib structures (4).

Description

The present invention relates to a method for mounting a heat exchanger. The invention also relates to a heat exchanger produced by this process.

Usually, heat exchangers are produced by brazing solder-plated flat tubes and fin structures arranged between them in brazing furnaces. However, just this soldering requires a lot of energy and thus makes the manufacturing process relatively expensive. In addition, for a dense and stable soldering usually a flux must be used, which is also expensive. Soldered heat exchangers also have only a reduced thermal shock resistance, which, however, can reduce the service life of soldered heat exchangers in the case of rapidly switching valves used today since, in particular, solder joints represent weak points with regard to thermal shock resistance. On the other hand, mechanical coolers with, for example, internally flared flat tubes for connecting them to the rib structure arranged therebetween, in turn require a larger space requirement and therefore have a lower power density.

The present invention therefore deals with the problem of providing a novel method for producing a heat exchanger, by means of which mechanically joined radiator with high power density can be produced inexpensively.

This problem is solved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject of the dependent claims.

The present invention is based on the general idea to use for manufacturing or mounting a heat exchanger comparatively stable and stiff rib structures and compared to less rigid flat tubes, which also cambered, ie convex, have side walls and arranged only by pressure on the surface therebetween Rip structures abut, without a costly and energy-intensive and therefore expensive soldering must be done. In the method according to the invention for mounting a heat exchanger or a heat exchanger block with a plurality of flat tubes, in particular with convex side walls and rib structures arranged between adjacent flat tubes, an alternating stacking of the flat tubes and the rib structures to the heat exchanger block takes place, wherein the flat tubes with their convex side walls with the rib structures in FIG Standing in contact. Since the flat tubes have convex side walls in the initial state, contact of the flat tubes with the rib structures is only nearly linear. Subsequently, two aligned parallel to the flat tubes side parts are mounted, between which the heat exchanger block is arranged. Thereafter, a permanent compressive force on the two side parts is applied to the heat exchanger block and this pressed together until the convex side walls of the flat tubes are at least almost flat and create a flat against the rib structures and the side panels. The permanent application of the compressive force on the heat exchanger block can be done for example by means of threaded rods, drawstrings, pull wires or other tie rods. Due to the comparatively stiff rib structures and the comparatively much softer side walls of the flat tubes, a full-surface contact between the flat tubes on the one hand and the rib structures arranged therebetween on the other hand can be achieved, which ensures a high heat transfer and thus a high power density. The so only mechanically stretched heat exchanger block has no more solder joints and thus no weaknesses in terms of thermal shock resistance. The good heat-transferring contact that was previously guaranteed by solder is now achieved by means of the "soft" and convex sidewalls, which lie flat against the interposed rib structures when mounted. The good heat-transferring contact is ensured in this case by means of the permanently applied tensile force and the deformable side walls. A heat exchanger or heat exchanger block produced by means of the method according to the invention offers the great advantage that neither solder-plated flat tubes nor flux (fluxing agent) nor soldering is required and, moreover, a heat exchanger with high power density, small installation space and, at the same time, high thermal break resistance can be created , Of course, it is clear that also material pairings can be used that can not be joined by soldering or other thermal processes: For example: pipes made of plastic / ribs made of aluminum.

In an advantageous development of the solution according to the invention, a sliding of tube sheets with passages on the longitudinal ends of the flat tubes takes place before or after the compression of the heat exchanger block. The tubesheets represent a part of a respective collector in a known manner, the flat tubes are sealed in corresponding passages of the tube sheets. Corresponding seals are arranged in the respective passages, so that soldering can also be dispensed with here, whereby the associated disadvantages, such as energy-intensive production and problematic thermal shock resistance, are eliminated. Alternatively, of course, is also conceivable that the Heat exchanger block initially produced and only in compressed state, the tubesheets are placed with their respective passages on the associated flat tubes, wherein then sealing the flat tubes in the passages by expanding the flat tube ends, for example by means of an expanding mandrel or a stamp done. In this case, no seal is required because the sealing of the flat tubes in the passages takes place via a mechanical deformation.

In a further advantageous embodiment of the method according to the invention are used in cross-section bone-shaped flat tubes with two round end portions and an intermediate central region with the two convex side walls Preferably, flat tubes are used, the end regions each have a radius R between 0.5 and 3 mm, in particular one each Radius R between 0.75 and 1.5 mm. In this way, in particular a displacement of the ribs can be prevented transversely to the pipe during operation. Alternatively, this can also be achieved by setting up the edges of the rib ("bumps").

In a further advantageous embodiment of the method according to the invention, turbulence contours are impressed in the side walls of the flat tubes. Such turbulence contours increase the surface available for heat transfer and thus also the heat exchanger's performance. In addition, when flowing through, they create a turbulence of the fluid flowing therein, which likewise improves heat transfer. The impressing of turbulence contours in at least one side wall of the flat tube allows a simple and inexpensive production.

The present invention is further based on the general idea to use a heat exchanger produced by this method, said heat exchanger has a significantly increased temperature or thermal shock resistance due to the no longer existing solder joints, which proves to be a great advantage especially in modern engine. To be able to react as quickly as possible to different load requirements or temperature conditions, nowadays usually electrically controlled valves are used, which can open or close comparatively quickly and thereby lead to an abrupt and high temperature load in the radiator. Since especially solder joints are weak points of the thermal resistance, can be significantly increased by eliminating these solder joints, the thermal shock resistance of the heat exchanger according to the invention. In addition, the production costs of the same can be reduced, since neither solder-plated flat tubes still expensive flux and no more expensive, as energy-intensive, soldering process must be used more.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

• 1 eine Seitenansicht auf einen erfindungsgemäß hergestellten Wärmeübertrager,
• 2 eine Detaildarstellung aus 1,
• 3 eine mögliche Ausführungsform eines in dem erfindungsgemäßen Wärmeübertrager eingesetzten Flachrohrs,
• 4 mehrere Querschnitte durch Flachrohre mit unterschiedlichen Turbulenzkonturen,
• 5 eine Ansicht auf einen Rohrboden mit Durchzügen und darin eingesetzten Flachrohren,
• 6a eine Schnittdarstellung eines alternativen Flachrohrs mit innenliegender Rippe,
• 6b eine Schnittdarstellung eines alternativen Flachrohrs,
• 7 eine Schnittdarstellung durch einen Wärmeübertrager mit einer Höcker aufweisenden Rippenstruktur.

Show, in each case schematically,

• 1 a side view of a heat exchanger according to the invention,
• 2 a detailed view 1 .
• 3 a possible embodiment of a flat tube used in the heat exchanger according to the invention,
• 4 several cross sections through flat tubes with different turbulence contours,
• 5 a view of a tube plate with passages and flat tubes inserted therein,
• 6a a sectional view of an alternative flat tube with internal rib,
• 6b a sectional view of an alternative flat tube,
• 7 a sectional view through a heat exchanger with a bump-containing rib structure.

According to the 1 . 2 . 5 and 7 , Has a heat exchanger according to the invention 1 several flat tubes 2 with convex side walls 3 (See also the 3 and 4 ) and between adjacent flat tubes 2 arranged rib structures 4 on. The flat tubes 2 and the interposed rib structures 4 form a heat exchanger block 5 by alternately stacking the flat tubes 2 and the rib structures 4 is made. The flat tubes 2 stand over their convex, that is cambered, side walls 3 with the rib structures 4 in contact.

The heat exchanger according to the invention is produced or mounted in this case 1 as follows:

First, the flat tubes 2 and the rib structures 4 alternating with the previously described heat exchanger block 5 stacked, with the flat tubes 2 first over its convex sidewalls 3 in almost linear contact with the rib structures 4 stand. Subsequently, two are parallel to the flat tubes 2 aligned side parts 6 attached and applied over this a permanent compressive force, whereby the heat exchanger block 5 compressed and the convex sidewalls 3 the flat tubes 2 at least nearly plan and flat to the rib structures 4 invest. To achieve this is the rigidity of the rib structures 4 in the transverse direction of the flat tubes 2 significantly greater than the stiffness of the flat tubes 2 in their transverse direction, which is achieved for example by the fact that the rib structure 4 according to the 2 having shown triangular meandering structure.

Before or after the compression of the heat exchanger block 5 becomes a tube sheet 7 (see. 5 ) with passages 8th on the longitudinal ends 9 the flat tubes 2 deferred, with a sealing of the flat tubes 2 in the passages 8th by providing a seal 10 or by widening the flat tube ends 9 in the respective passage 8th he follows. An expansion of the flat tube ends, that is the longitudinal ends 9 the flat tubes 2 can be done for example by introducing an expanding mandrel or a stamp.

The compression of the heat exchanger block 5 For example, by threaded rods 11 (see. 1 ), which are the side parts 6 penetrate and are screwed to this. Alternatively, of course, it is also conceivable that tie rods 12 , Pull wires or drawstrings 13 (see. 2 ) are used.

Considering the flat tubes preferably used 2 according to the 3 to 5 , it can be seen that these are bone-shaped in cross-section, with two round end portions 14 and an intermediate area between them 15 with two convex side walls 3 , The end areas 14 in this case preferably each have a radius R of 0.1 mm <R <0.8 mm, in particular in each case a radius R of 0.3 mm <R <0.5 mm.

Looking at the flat tubes 2 according to the 6a and 6b So you can tell that these rounded end areas 14 and each intermediate area 15 with convex side walls 3 having. The round end areas 14 in this case preferably each have a radius R of 0.1 mm <R <0.8 mm, in particular in each case a radius R of 0.3 mm <R <0.5 mm.

The bone shape of the flat tubes 2 additionally serves for the frictional connection between the flat tube applied by the clamping 2 and rib structure 4 to make a positive connection. This will cause the rib structure to slip 4 during cooler installation and during operation additionally prevented. Another option is a non-slip connection between the rib structure 4 and the adjacent flat tube 2 For example, the rib structure is to be produced 4 with humps 18 to provide, as in 7 is shown. The humps 18 can be integral with the rib structures 4 trained or connected with these.

The flat tubes 2 can be designed as welded or extruded tubes and their central region 15 internal turbulence contours 16 have, as according to the 4 is shown. These turbulence contours 16 increase the heat transfer surface and also cause a turbulent flow within the flat tube 3 , whereby the heat transfer and thus the performance of the heat exchanger 1 can be increased. The turbulence contours 16 can do this in the associated side wall 3 embossed and thus manufactured comparatively inexpensively. Also an extrusion is possible here by a variable extrusion die.

With the heat exchanger according to the invention 1 , whose heat exchanger block 5 is no longer soldered, but permanently via corresponding threaded rods 11 or tie rods 12 , Pull wires or drawstrings 13 mechanically braced, solder joints can be completely avoided, which not only the elimination of solder plated flat tubes is possible, but also weak points in terms of thermal shock resistance can be avoided. This is of particular advantage in modern internal combustion engines or engines which have fast and high temperature changes. By referring to the flat tubes 2 significantly stiffer rib structures 4 In addition, a compression of the heat exchanger block 5 take place, whereby this space is designed to optimize space. The mechanical distortion of the heat exchanger block 5 also causes a surface conditioning of the side walls 3 the respective flat tubes 2 at the associated rib structures 4 and thus an optimal heat transfer.

Claims (10)

Method for mounting a heat exchanger (1) with a plurality of flat tubes (2) with convex Side walls (3) and between adjacent flat tubes (2) arranged rib structures (4) which are formed in the transverse direction stiffer than the flat tubes (2), with the method steps - alternately stacking the flat tubes (2) and the rib structures (4) to a heat exchanger block (5), wherein the flat tubes (2) with their convex side walls (3) with the rib structures (4) are in contact, - attaching two parallel to the flat tubes (2) aligned side parts (6), - applying a permanent compressive force on the two side parts (6) and compression of the heat exchanger block (5) to the convex side walls (3) of the flat tubes (2) are at least almost flat and create a flat against rib structures (4). Method according to Claim 1 , characterized by a sliding of tube sheets (7) with passages (8) on longitudinal ends (9) of the flat tubes (2) before or after compression of the heat exchanger block (5). Method according to Claim 2 , characterized by , sealing the flat tubes (2) in the passages (8), in particular by widening the longitudinal ends (9) of the flat tubes (2) or by arranging a respective seal (10) in an associated passage (8). Method according to Claim 3 , first alternative, characterized in that the widening of the longitudinal ends (9) of the flat tubes (2) takes place by introducing an expanding mandrel or a punch. Method according to one of the preceding claims, characterized in that the compression of the heat exchanger block (5) by threaded rods (11), tie rods (12) or drawstrings (13). Method according to one of the preceding claims, characterized in that in cross-section bone-shaped flat tubes (2) with two round end regions (14) and an intermediate central region (15) with the two convex side walls (3) are used. Method according to Claim 6 , characterized in that flat tubes (2) are used, whose end regions (14) each have a radius of 0.1 mm <R <0.8 mm, in particular each have a radius 0.3 mm <R <0.5 mm. Method according to Claim 6 or 7 , characterized in that flat tubes (2) are used, - which are formed as welded or extruded tubes, and / or - in its central region (15) have internal turbulence contours (16). Method according to Claim 8 , characterized in that the turbulence contours (16) are embossed in an associated side wall (3). Heat exchanger (1) produced by the method according to one of the preceding claims.

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