EP3489610A1

EP3489610A1 - Heat exchanger

Info

Publication number: EP3489610A1
Application number: EP17203841.6A
Authority: EP
Inventors: Thierry Berger
Original assignee: Mahle International GmbH
Current assignee: Mahle International GmbH
Priority date: 2017-11-27
Filing date: 2017-11-27
Publication date: 2019-05-29

Abstract

The invention relates to a heat exchanger (10) comprising a plurality of flat tubes (30), which are arranged next to one another in at least one row and which are held in tube plates (20) on both ends so as to be sealed, as well as comprising a support device (40), which prevents a widening of the flat tubes (30) and which has spacers (42), which run parallel to the tube plates (20) and which run between the side walls (32) of adjacent flat tubes (30).

For the improved support effect, it is proposed for the spacers (42) to have flat attachments (44, 54), which extend parallel to the side walls (32) of the flat tubes (30) in the longitudinal direction of the flat tubes (30).

Description

The invention at hand relates to a heat exchanger comprising a plurality of flat tubes, which are arranged next to one another in at least one row and which are held in tube plates in both ends so as to be sealed.
Heat exchangers are used for example in motor vehicles and generally comprise a heat exchanger block, among others, which is substantially formed by flat tubes, ribs or lamellae as well as tube plates, as well as a header and/or distribution box or a deflection box. Typically, the heat exchanger block and the header and/or distribution box or deflection box are connected to one another mechanically at the tube plates by means of a clamp connection or flare coupling, and provision can in each case be made for rubber seals to seal between the tube plates of the heat exchanger block and the header and/or distribution box or deflection box. In the alternative, provision can also be made for solder connections, which seal simultaneously. Typically, the heat exchanger block consist of a metallic material, such as for example an aluminum material, and the header and/or distribution box or deflection box consists of a plastic.
A heat exchanger, in the case of which a strengthening comb is in each case arranged on the side of the tube plates, which faces the flat tubes, is known from DE 199 258 595 . The strengthening comb has a row of teeth, which engage with the spaces between the side walls of adjacent flat tubes and which are connected to the tube plates, but not to the tubes themselves. The tube plates are stabilized and strengthened by means of this design, so that the tube plates, which form a part of the header and/or distribution box or deflection box, can be subjected to a higher pressure. The operating pressure of this known heat exchanger can thus be increased and the pressure retaining capacity is improved, without significantly increasing the weight.
A heat exchanger, in the case of which provision is made for support means, which prevent a widening of the flat tubes and which are embodied as spacers, which run parallel to the tube plates, and which run between the side walls of adjacent flat tubes, is known from EP 0 479 012 . These spacers secure the distance of the side walls of adjacent flat tubes in the connecting area of the tube plate, in order to prevent a widening of the flat tubes in this area, which is caused by an overpressure load.
In the case of these known heat exchangers comprising flat tubes, stability and/or leak tightness problems can appear under the impact of an increased and changing load, which is required for certain applications. An increased load can appear for example due to high internal pressures and/or a large number of internal pressure changes or changing temperature loads. In the case of longer and higher loads, there is thus the risk that a widening of the flat tubes, which is in particular caused by the internal pressure change and changing temperature loads, appears, which can lead to an impairment or, in the worst case, also to damages to the heat exchanger.
Against this background, it is thus the object of the invention at hand to provide a heat exchanger block, which avoids the above-mentioned disadvantages.
According to the invention, this object is solved by means of the subject matter of the independent claim. Advantageous embodiments are the subject matter of the dependent claims.
The invention at hand is based on the general idea of providing support means, which prevent a widening of the flat tubes and which are embodied as spacers, which run parallel to the tube plates, wherein the respective spacer is characterized in that it has flat attachments or attachment structures, which extend parallel to the side walls of the flat tubes in the longitudinal direction of the flat tubes. The flat tubes are thus supported across a longer distance than this is known to date from the prior art, along their side walls, and are held apart from one another at a specified distance. A widening of the flat tubes is thus not only prevented in the immediate vicinity of the tube plates, but across a relatively long distance of the flat tubes, which reaches far into the heat exchanger block. At best, the attachments can extend to the ribs or lamellae, which connect the flat tubes to one another.
A load on the seal of the flat tubes is reduced significantly or even prevented through this even in response to longer and higher load on the heat exchanger, and a widening of the flat tubes, which reduces the service life of the flat tubes and which is caused by the internal pressure changes and changing temperature loads, is prevented or at least reduced significantly. As a result, the risk of damages to the seal of the flat tubes in the tube plates is reduced significantly, so that the reliability and service life of the heat exchanger according to the invention is increased significantly. As a further result, the reliability and service life of the flat tubes is also increased significantly due to the prevented or reduced widening thereof.
The flat attachments can hereby advantageously be embodied in such a way that they extend from the tube plate parallel to the side walls of the flat tubes in the longitudinal direction of the flat tubes and are thereby supported in a planar manner on the respective flat tube. The attachments preferably extend to the ribs or lamellae. Moreover, the flat attachments can hereby advantageously be embodied in such a way that they extend at least across the entire width of the flat tube to the side edges of the flat tube, or that they extend beyond one or both side edges of the flat tube. A large contact surface, which covers the side wall of the flat tube substantially across its entire width, is thus provided, so that the high compressive forces, which appear during the operation of the heat exchanger, can be absorbed, in order to reliably prevent a widening of the flat tubes.
Each spacer preferably has two such attachments or attachment structures, which extend parallel to one another and which are spaced apart from one another. The respective spacer can further have a holding area, which abuts on the respective tube plate and from which the respective attachment sticks out. The respective spacer can thus in particular have a substantially U-shaped cross sectional profile, wherein the two U-legs form two attachments, which are connected to one another via the U-base, which forms the holding area.
According to a particularly advantageous embodiment, the spacers are embodied on at least one support comb, which can be inserted at right angles to the longitudinal axes of the flat tubes. The support comb has a comb back, from which the spacers stick out sort of like teeth. A simplified assembly of a heat exchanger according to the invention is thus possible, in that the respective support comb is simply inserted with its spacers into the pre-assembled heat block, parallel to the tube plates. A plurality of individual spacers can hereby be assembled simultaneously in each case.
All of the spacers, which are assigned to the respective tube plate, are preferably embodied at a single one of such support comb.
Parallel to its longitudinal direction, in which the spacers or the teeth, respectively, follow one another, the comb back can have an L-shaped cross sectional profile. The spacers originate at the one or first L-leg, while the other or second L-leg can come to rest laterally on the respective tube plate and can in particular be fastened thereto, e.g. by means of soldering. Said second L-leg can laterally encompass the tube plate in this respect.
According to the invention, provision is made for the support comb to have teeth, wherein the teeth have a U-shaped cross section. The teeth form the spacers. The legs of the U-shaped teeth are embodied as flat attachments, which extend parallel to the side walls of the flat tubes in the longitudinal direction of the flat tubes.
The flat tubes are thus supported across a larger distance along their side walls and are held at a specified distance from one another, so that a widening of the flat tubes is not only prevented in the immediate vicinity of the tube plates, but across a long distance of the flat tubes, which reaches far into the heat exchanger block.
A widening of the flat tubes can be prevented even better, when the flat attachments of the teeth abut on the side walls of the flat tubes, which is provided according to a further preferred embodiment. A widening of the flat tubes is almost completely prevented through this. If, however, a certain widening of the flat tubes is to be permitted, which may be advantageous in the case of certain applications, the flat attachments of the teeth can be arranged so as to be spaced apart from the side walls of the flat tubes at a predetermined distance, which corresponds to the permitted widening.
The support comb can be made of any material, which is suitable for the application purpose, which meets the requirements on temperature resistance, heat resistance, weight, etc.. For example, plastics, light metal alloys or non-ferrous metals can be used. However, aluminum turned out to be particularly advantageous, so that it is provided according to the invention. Here, the support comb can be punched out of an aluminum sheet for example and can be brought into the desired shape by means of simple bending methods.
An embodiment, in the case of which the support comb is formed by means of a shaped sheet metal part, which is made of a single piece of sheet metal by means of forming, is particularly advantageous. For this purpose, the individual attachments can be cut free and exposed, e.g., in order to form the spacers, which then stick out from the comb back.
A further advantageous embodiment provides for the spacers to be embodied as at least one intermediate plate, which has a slit-like opening for guide-through of the flat tubes. In response to the assembly of the heat exchanger according to the invention, the flat tubes are inserted into the slit-like openings of the intermediate plate, wherein at least one intermediate plate is in each case arranged adjacent to a tube plate. A compact and in particular stable heat exchanger according to the invention is provided in this way.
To further improve the stability of the heat exchanger according to the invention, provision can advantageously also be made for further additional intermediate plates, which are spaced apart from the tube plates, to be arranged in the central area of the heat exchanger block.
Provision is made according to the invention for flat attachments, which extend parallel to the side walls of the flat tubes in the longitudinal direction of the flat tubes, to be embodied on the sides of the slit-like openings.
The flat tubes are thus supported across a larger distance along their side walls and are held at a specified distance from one another, so that a widening of the flat tubes is not only prevented in the immediate vicinity of the tube plates, but across a long distance of the flat tubes, which reaches far into the heat exchanger block.
A widening of the flat tubes can be prevented even better, when the flat attachments abut on the side walls of the flat tubes, which is provided according to a further preferred embodiment. A widening of the flat tubes is almost completely prevented through this. If, however, a certain widening of the flat tubes is to be permitted, which may be advantageous in the case of certain applications, the flat attachments can be arranged so as to be spaced apart from the side walls of the flat tubes at a predetermined distance, which corresponds to the permitted widening.
The intermediate plate can be made of any material, which is suitable for the application purpose, which meets the requirements on temperature resistance, heat resistance, weight, etc.. For example, plastics, light metal alloys or non-ferrous metals can be used. However, aluminum turned out to be particularly advantageous, so that it is provided according to the invention. Here, the intermediate plate can be punched out of an aluminum sheet and can be brought into the desired shape by means of simple bending methods.
The flat attachments can advantageously be adapted to the respective application and can be embodied in such a way that they extend parallel to the side walls of the flat tubes in the longitudinal direction of the flat tubes in the described manner in accordance with the invention.
Different design options are conceivable for the flat attachments, as long as it is ensured that they extend parallel to the side walls of the flat tubes at least partially in the longitudinal direction of the flat tubes in the assembled state, and advantageously abut on the side walls of the flat tubes. As discussed in detail above, it is also possible, however, for a certain widening of the flat tubes to be permitted, which may be advantageous in the case of certain applications, so that the flat attachments can be arranged at a predetermined distance, which corresponds to the permitted widening, from the side walls of the flat tubes.
The remaining parameters for forming the spacers with the flat attachments can also be adapted to the respective application. The width of the flat attachment as well as possibly their protrusion beyond the side edge of the side surface of the flat tube, the length of the flat attachment as well as the extension thereof from the tube plate, number of the support means or spacers, respectively, etc., among others, can be named here as relevant parameters.
The respective spacer can be fastened to the flat tubes, e.g. by means of a solder connection. Advantageously, the two attachments of the spacer are fixed to the two sides of the adjacent flat tubes, which face one another, by means of solder connections. The respective spacer can optionally be fixed to the respective end plate, e.g. by means of a solder connection. In the case of a spacer comprising a U-shaped cross section, the two U-legs are fixed to the adjacent flat tubes, while the U-base may be fixed to the respective tube plate.
Further important features and advantages of the invention follow from the subclaims, from the drawings, and from the corresponding figure description by means of the drawings.
It goes without saying that the features, which are mentioned above and which will be discussed below, cannot only be used in the respective specified combination, but also in other combinations or alone, without leaving the scope of the invention at hand.
Preferred exemplary embodiments of the invention are illustrated in the drawings and will be discussed in more detail in the description below, whereby the same reference numerals refer to identical or similar or functionally identical components.
In each case schematically:

Fig. 1: shows a top view onto a heat exchanger block (10) according to the invention comprising two tube plates (20) and flat tubes (30) arranged therebetween,
Fig. 2: shows an isometric partial view of a first embodiment of a support comb (40) according to the invention comprising U-shaped teeth (42),
Fig. 3: shows an isometric partial view of a second embodiment of a support comb (40) according to the invention comprising U-shaped teeth (42),
Fig. 4: shows an isometric partial view of an intermediate plate (50) according to the invention comprising flat attachments (54).

In a top view, Fig. 1 shows a heat exchanger block 10 according to the invention comprising two tube plates 20 and flat tubes 30 arranged between the tube plates 20. The flat tubes 30 are in each case arranged in a tube plate 20 with their ends so as to be sealed. Lamellae or ribs 70, which are advantageously soldered to the flat tubes 30, are arranged in the gaps of adjacent flat tubes 30. Only a few of such ribs are suggested in an exemplary manner in Fig. 1. The tube plates 20 in each case form a part of a box, which is not identified in more detail here, which can be a distribution box or a header box or a deflection box or a combined header and distribution box. A support device 40 is arranged on each tube plate 20 so as to abut on the side, which faces the flat tubes 30. In the case of the embodiment illustrated here, the support device 40 is embodied by a support comb 60, which is inserted laterally or from the top, respectively, or in the viewing direction of Fig. 1, respectively, into the heat exchanger block 10 illustrated here, and which is supported on the top side of the tube plate 20 by means of a support 46. The support 46 is thereby part of a comb back 48 of the support comb 60. The support comb 60 is held in its predetermined spot in a secure and reliable manner through this, and can additionally also be fastened to the top side of the tube plate 20 by means of suitable and known fastening means, which even further improves the reliability and service life of the heat exchanger block 10 according to the invention. The support comb 60 is preferably soldered to the respective tube plate 20.
On its side, which faces the flat tubes 30, the support comb 60 has a number of teeth 42, which are embodied in a U-shaped manner and which can basically act as spacers and which can also be identified as spacers 42 below. The spacers 42 or teeth 42 engage with the gaps of adjacent flat tubes 30, namely between the respective tube plate 20 and the ribs 70. The number of the teeth 42 or spacers 42, which are embodied in a U-shaped manner, preferably corresponds to the number of the flat tubes 30, minus one, that is, provision is made for n-1 spacers 42 in the case of n flat tubes 30. The legs of the teeth 42, the profile of which is embodied in a U-shaped manner, are in each case embodied as flat attachments 44, which abut on the side walls 32 of the flat tubes 30. The support comb 60 will be discussed in more detail later with reference to Fig. 2. Every spacer 42 or tooth 42, which has a U-shaped profile, thus has two such attachments 44 here, which abut on side walls 32, which face one another, of adjacent flat tubes 30.
As can be seen well here, each end of the flat tubes 30 is supported by the flat attachments 44, wherein the flat attachments 44 in each case extend parallel to the side walls 32 of the flat tubes 30 in the longitudinal direction of the flat tubes 30. The flat tubes 30 are thus supported across a larger distance along their side walls 32 and are held at a specified distance from one another. A widening of the flat tubes 30 is thus not only prevented in the immediate vicinity of the tube plates 20, but across a relatively long distance of the flat tubes 30, which reaches into the heat exchanger block 10. These attachments 44 preferably extend all the way to the ribs 70.
In the case of longer and higher loading of the heat exchanger block 10, a loading of the seal of the flat tubes 30 in the tube plates 20 is also reduced significantly or even prevented through this, and a widening of the flat tubes 30, which reduces the service life of the flat tubes 30 and which is caused by the internal pressure changes and changing temperature loads, is prevented or at least reduced significantly. As a result, the risk of damages to the seal of the flat tubes 30 in the tube plates 20 is reduced significantly, so that the reliability and service life of the heat exchanger block 10 according to the invention is increased significantly. As a further result, the reliability and service life of the flat tubes 30 is also increased significantly due to the prevented or reduced widening thereof.
Fig. 2 shows an isometric partial view of a first embodiment of a support comb 60 according to the invention comprising U-shaped teeth 42 or spacers 42, respectively.
The spacers 42, which are embodied in a U-shaped manner and which extend from the comb back 48, can be seen clearly in this isometric partial view of the support comb 60 according to the invention. At right angles to the direction, in which the spacers 42 follow one another, the comb back 48 can have an L-shaped profile, e.g. to form the support 46, namely as one leg of the L-profile. The legs 44 of the teeth or spacers 42, which are embodied in a U-shaped manner, form the flat attachments 44, which, as already discussed, abut on the side walls 32 (not illustrated here) of the flat tubes 30 (not illustrated here) and which in each case extend parallel to the side walls 32 (not illustrated here) of the flat tubes 30 (not illustrated here) in the longitudinal direction of the flat tubes 30 (not illustrated here).
Here, the flat attachments 44 are advantageously embodied in such a way that they extend at least across the entire width of the flat tube 30 (not illustrated here) to the side edges of the flat tube 30 (not illustrated here). A large attachment surface, which covers the side wall 32 (not illustrated here) of the flat tube 30 (not illustrated here) substantially across its entire width, is thus provided, so that the high compressive forces, which appear during the operation of the heat exchanger, can be absorbed in order to reliably prevent a widening of the flat tubes 30 (not illustrated here). The spacers 42, which have a U-shaped profile, thereby extend in the width direction of the flat tubes 30.
The support comb 60 can support itself on a longitudinal side of the tube plate 20 (not illustrated here) by means of the support 46. The support comb 60 is held in its predetermined spot in a secure and reliable manner through this and can additionally also be fastened on the side of the tube plate 20 (not illustrated here) by means of suitable and known fastening means, which further improves the reliability and service life of the heat exchanger block 10 (not illustrated here) according to the invention.
The support comb 60 comprising the U-shaped teeth 42 is punched out of an aluminum sheet and can be brought into the desired form by means of simple bending methods. It is thus a shaped sheet metal part, which is made of a single piece of sheet metal by means of forming.
Fig. 3 shows an isometric partial view of a second embodiment of a support comb 60 according to the invention comprising U-shaped spacers 42 or teeth 42, respectively. Identical components are provided with identical reference numerals here, so that a description of these components does not need to be repeated here.
The teeth 42, which are embodied in a U-shaped manner and which extend from the comb back 48, can also be seen clearly in the case of this embodiment of a support comb 60 according to the invention. The legs 44 of the teeth 42, which are embodied in a U-shaped manner, form the flat attachments 44, which, as already discussed, abut on the side walls 32 (not illustrated here) of the flat tubes 30 (not illustrated here) and which in each case extend parallel to the side walls 32 (not illustrated here) of the flat tubes 30 (not illustrated here) in the longitudinal direction of the flat tubes 30 (not illustrated here).
The support 46 on the comb back 48 of the embodiment illustrated here of a support comb 60 according to the invention is bent over and is embodied in such a way that the support comb 60 can encompass the respective bottom plate (not illustrated) on the longitudinal side thereof. The support comb 60 is held in its predetermined spot in a secure and reliable manner through this and can additionally also be fastened to the longitudinal side of the end plate 20 (not illustrated here) by means of suitable and known fastening means, which further improves the reliability and service life of the heat exchanger block 10 (not illustrated here) according to the invention.
Here, the support comb 60 comprising the U-shaped teeth 42 is punched out of an aluminum sheet and can be brought into the desired shape by means of simple bending methods.
Fig. 4 shows an isometric partial view of an intermediate plate 50 according to the invention comprising slit-shaped openings 52 and flat attachments 54. The flat attachments 54 are embodied on the sides of the slit-like openings 52 and abut on the side walls 32 (not illustrated here) of the flat tubes 30 (not illustrated here), as already discussed, and in each case extend parallel to the side walls 32 (not illustrated here) of the flat tubes 30 (not illustrated here) in the longitudinal direction of the flat tubes 30 (not illustrated here).
The slit-like openings 52 serve for the guide-through of the flat tubes 30 (not illustrated here), which are inserted into the slit-like openings 52 of the intermediate plate 50 in response to the assembly of the heat exchanger block 10 (not illustrated here). The openings 52 thereby encompass the flat tubes 30 in the circumferential direction thereof. The intermediate plate comprising the openings 52 and the attachments 54 also forms a support device 40.
Here, the intermediate plate 50 comprising the flat attachments 54 is punched out of an aluminum sheet and has been brought into the desired shape by means of simple bending methods.

Claims

A heat exchanger comprising a plurality of flat tubes (30), which are arranged next to one another in at least one row and which are held in tube plates (20) on both ends so as to be sealed, as well as comprising a support device (40), which prevents a widening of the flat tubes (30) and which has spacers (42), which run parallel to the tube plates (20) and which run between the side walls (32) of adjacent flat tubes (30),
characterized in that
the spacers (42) have flat attachments (44, 54), which extend parallel to the side walls (32) of the flat tubes (30) in the longitudinal direction of the flat tubes (30).
The heat exchanger according to claim 1, characterized in that the spacers (42) are embodied on at least one support comb (60), which can be inserted at right angles to the longitudinal axes of the flat tubes (30), wherein the teeth of the support comb (60) form the spacers (42).
The heat exchanger according to claim 1 or 2, characterized in that the support comb (60) is embodied as shaped sheet metal part, which is made of a single piece of sheet metal by means of forming.
The heat exchanger according to one of the preceding claims, characterized in that the spacers (42) have a U-shaped cross section, and wherein the legs of the U-shaped spacers (42) are embodied as flat attachments (44), which extend parallel to the side walls (32) of the flat tubes (30) in the longitudinal direction of the flat tubes (30).
The heat exchanger according to claim 1, characterized in that the spacers (42) are embodied on at least one intermediate plate (50), which has slit-like openings (52) for guide-through of the flat tubes (30), wherein the flat attachments (54), which extend parallel to the side walls (32) of the flat tubes (30) in the longitudinal direction of the flat tubes (30), are embodied on the sides of the slit-like openings (52).
The heat exchanger according to claim 5, characterized in that the intermediate plate (50) is embodied as shaped sheet metal part, which is made of a single piece of sheet metal by means of forming.
The heat exchanger according to one of the preceding claims, characterized in that the flat attachments (44, 54) abut on the side walls (32) of the flat tubes (30).
The heat exchanger according to claim 7, characterized in that the attachments (44, 54) are soldered to the flat tubes (30).
The heat exchanger according to one of the preceding claims, characterized in that the flat tubes (30) are made of a metallic construction material, and in particular of aluminum or a non-ferrous metal.
The heat exchanger according to one of the preceding claims, characterized in that the spacers (42) and/or the support comb (60) are/is fastened to the respective end plate (20) by means of soldering.