EP1647341B1 - Method for making a corrugated fin and heat exchange block containing these corrugated fins - Google Patents

Description

The invention relates to a method for producing a corrugated fin for a consisting of at least two Wärmeübertragem heat exchanger block according to the preamble of claim 1. Furthermore, the invention relates to a heat exchanger block consisting of at least two Wärmeübertragem, according to the preamble of claim 9. Such a method and such Heat exchanger block are from the EP-A-0 431 917 known.

Heat exchanger blocks or heat exchanger modules, which consist of at least two different Wärmeübertragem were known under the name protected for the applicant Monoblock . In this case, a coolant flowed through by coolant on the primary side and a condenser through which refrigerant flows on the primary side are integrated into a heat exchanger block, wherein both heat exchangers are arranged one behind the other in the air flow direction and have common corrugated fins, so-called continuous ribs, overflowed by ambient air. The entire heat exchanger block, preferably made of aluminum, is soldered "in one shot" in a soldering oven. However, such a heat exchanger block may also include other heat exchangers, such as a charge air cooler. By the DE-A 197 22 097 the Applicant has such a monoblock is known, which is also characterized in that at least one heat exchanger, preferably the cooler, has no conventional tube sheet, but instead flared end flat tubes, with their long sides with each other and with their Narrow sides are soldered to a collection box. This design brings significant benefits in the depth, ie in the air flow direction. As already mentioned, the heat exchangers carry their heat to the ambient air via a common or continuous rib, which has the mechanical advantage that it gives the heat exchanger block the required stiffness, but thermodynamically has the disadvantage that a heat conduction through the rib of a Heat exchanger to the other takes place, for example, from the radiator to the condenser. This is not wanted. It has therefore been proposed so-called thermal barriers or thermal insulation for the corrugated fins in the transition region of a heat exchanger to another, whereby the heat conduction should be prevented or at least greatly reduced. For example, by the applicant in the DE-A 198 08 202 proposed to pierce the corrugated fins in the region of their wave crests, so that torn passages arise, which interrupt the heat conduction in the corrugated fin. This solution has the advantage, among other things, that no material waste is produced, but the thermal insulation is not always sufficient.

In the EP-A 367 078 Slots were proposed for a heat exchanger block with continuous corrugated rib, which are punched out of the corrugated rib for the purpose of suppressing the heat conduction. The punched rib parts are material waste, its disposal is associated with additional difficulties. Similar proposals of punched slots of different form go from the EP-A 431 917 out. Also, there is the disadvantage of material waste. Incidentally, these heat exchanger blocks deviate from the monobloc design of the Applicant insofar as not only the condenser but also the radiator have conventional tube sheets with passages into which the flat tubes are inserted. This results in a greater depth and a greater distance between the rows of tubes cooler and condenser. In a continuous corrugated fin, which is also desirable in this design due to its advantages, is consumed by this "bridging", in which the thermal barrier is installed, additional fin material, which does not heat transfer and the increase in performance of the heat exchanger, but additional weight and Cost means.

Further suggestions for solving this problem are taken from the EP-A 1 164 345 where an attempt is made to use the thermal breakaway bypass zone also for heat transfer. Again, additional material is consumed or there is waste in the production of the rib.

In the EP-A 1 241 424 a thermal barrier for a corrugated fin of a so-called duplex heat exchanger is proposed, which consists of so-called half gills, ie a cut out of the rib plane and upwardly or downwardly shaped gill. Although this solution is waste-free, but has the disadvantage that rib material is required for the bridging zone or thermal barrier zone, which does not serve for heat transfer.

Finally, in the EP-A 1 176 378 proposed a method for producing a corrugated fin with a thermal barrier, in which the rib is divided by longitudinal separating cuts and held together only by arranged between the longitudinal sections material characteristics or bridged. By planarizing the shapes, the fin material is stretched in the region of the bridges, and the cut edges of the separating cuts move away from one another in such a way that insulating air gaps are formed. In a further embodiment, separating cuts extending in the longitudinal direction are also provided, which overlap in the longitudinal direction, wherein thin material tongues are left in the region of the overlap. The rib is then stretched in the width so that the cut edges separate and form air gaps between the two rib areas. The tongues are deformed when pulled apart and form connecting sections between the two rib parts. Although no material blending results in the production of this known rib, however, problems in the plating of the characteristics are to be expected, for. B. in the form of material distortions or internal stresses, if, for example, move the rib rows along the rolling direction into one another.

It is an object of the present invention to provide a manufacturing method of the type mentioned, which allows a waste-free production of a corrugated fin with thermal barrier, the material use for the rib as low as possible, d. H. should be limited to the zones of heat transfer. Femer it is an object of the invention to provide a heat exchanger block with such a corrugated fin, which is produced without waste and with little use of material. In particular, it is an object of the invention to also bridge larger distances between the rows of tubes of the heat exchanger.

This object is first achieved by the features of claim 1. The corrugated fin is first made of a flat metal strip into which gills are cut by means of cutting rollers to improve the heat transfer, which are arranged in rows transversely to the rolling direction. The rib is then separated in the region of the thermal barrier, ie approximately in the middle, in each case between directly or indirectly adjacent gills and then pulled apart (transversely to the rolling direction). At the same time or after, the rib is pleated, ie wavy. By pulling apart the rib is widened, ie its depth in the air flow direction in the heat exchanger is greater, namely around the area of the thermal barrier zone between the rows of tubes of the heat exchanger. The separation of the rib is made without waste, so that no rib material particles are incurred, which must be disposed of. This facilitates the manufacturing process. By appropriate positioning of the separation points, the rib can pull apart like a concertina or garland, resulting in a thermally effective "exclusion zone", ie a thermal barrier and only one or two thin material webs are retained, which hold the rib parts together and allow only a small heat conduction , This separation technique also larger distances can be bridged, which depends on the design of the relevant Wärmeübertragerblvckes, ie the distance of the rows of tubes. The solution according to the invention is the more advantageous the material saving in the rib, the greater the distance to be bridged.

The preparation of the corrugated fin need not necessarily - as explained above - be carried out in a continuous process with an endless metal strip, which is guided by a rotating pair of rollers. Rather, it is also within the scope of the invention, auszustanzen a rib with gills and cuts from a metal sheet (board) and then pull apart to form the thermal barrier.

According to an advantageous embodiment of the invention, the separation of the rib is carried out by running in the rolling direction and / or transverse to the rolling direction cuts, d. H. small cuts between adjacent gills, in the same gill row and between adjacent gill rows. This cutting technique has the advantage that it can be achieved directly during rolling by slight changes in the cutting rollers. The cuts according to the invention are thus produced, as it were, in one operation with the cutting of the gills.

According to an advantageous embodiment of the invention, the distances of the gills in a row in the area of the exclusion zone are increased - this results in other cutting combinations and a different geometric configuration of the connecting webs.

According to a further advantageous embodiment of the invention take the connecting webs after the pulling apart of the corrugated fin about the shape of a rhombus or a garland. Thus, there are only one or two thin connecting webs between the two rib parts, at the same time a relatively large distance is bridged with minimal material costs. Thus, both rib parts form a coherent structure, which can be further processed as a part and mounted (cassetted) in the heat exchanger block.

The object is also solved by the features of claim 9. Since this heat exchanger at least two rows of flat tubes has and the corrugated fin, despite thermal barrier is a continuous rib, it can be much easier cassettes with the tubes of the heat exchanger, ie prepare for the soldering process. The thermal barrier or the bridging is formed only by thin connecting webs of the fin material, which webs are arranged at an acute or obtuse angle to each other and made without waste. The thermal barrier or thermal insulation is achieved by a relatively low heat-conducting cross section and a relatively large length due to the angular arrangement of the legs.

Fig. 1

ein erstes Ausführungsbeispiel der Erfindung für die Herstellung einer Wellrippe mit drei Verfahrensschritten a), b), c) und

Fig. 2

ein zweites Ausführungsbeispiel der Erfindung mit drei Verfahrensschritten a), b), c).

Embodiments of the invention are illustrated in the drawings and will be described in more detail below. Show it

Fig. 1

a first embodiment of the invention for the production of a corrugated fin with three process steps a), b), c) and

Fig. 2

A second embodiment of the invention with three process steps a), b), c).

Fig. 1 shows three production sections a), b) and c) for a corrugated fin 1, which is shown in c) in the installed state of a heat exchanger block 2 only partially shown. The heat exchanger block 2 consists - as is known - of two heat transfer, which are shown schematically here by a first row of tubes 3 of a coolant radiator and a second row of tubes 4 of a refrigerant condenser. The series 3 consists of flat tubes 5, which are flowed through by coolant of a coolant circuit of an internal combustion engine of a motor vehicle, not shown, and the row 4 of multi-chamber flat tubes 6, which are traversed by refrigerant of a refrigerant circuit, not shown, of an air conditioning system of a motor vehicle. Both media, coolant and refrigerant, have different temperature levels, so that there is a temperature gradient, mostly from the cooler to the condenser. The two rows of tubes 3, 4 have a distance A, which is given on the one hand for reasons of isolation and on the other hand due to the design of the heat exchanger block. The corrugated fins 1 are between the Flat tubes 4 and 5 are arranged, wherein each corrugated fin 1 consists of two rib sections 1 a for the flat tubes 5 of the radiator and 1b for the flat tubes 4 of the capacitor. These rib sections 1a, 1b are occupied with gills 7, which serve to improve the heat transfer with the ambient air, which flows in the direction of the arrow L via the corrugated fins 1. The gills 7 may be the same or different for the rib sections 1a, 1b, depending on the design of the relevant heat exchanger. Between the two rib portions 1a 1b in the region of the distance A between the rows of tubes 3, 4, a connecting web 8 is arranged, which has two acute angles to each other arranged legs 8a, 8b, which are connected with their free ends with the rib portions 1a, 1b. The connecting web 8 acts as a so-called thermal barrier and prevents or reduces the heat conduction from one rib section 1 a to the other 1 b. The term "thermal barrier" is not to be understood as meaning that heat conduction between the fin sections 1a, 1b is completely excluded, but interpreted in accordance with the prior art explained in the introduction in that the heat conduction from one to the other rib section is so The two legs 8a, 8b of the connecting web 8 have in total a length which is greater than the distance A between the two rib sections 1a, 1b or the rows of tubes 3 This means that a longer path than the direct path of the distance A results for the heat conduction between the two rib sections 1a, 1b: This results in a further reduction of the heat conduction.

In the following, the production of the corrugated fin 1 will be explained with reference to the production sections a), b). The process section a) shows a flat, endless metal strip 9 of width B1 with uniformly arranged rows 10 of gills 11. The gills 11 are in a conventional manner when passing through cutting rollers, not shown in the direction of the arrow W, ie in the rolling direction in the metal strip 9 cut. In the central region of the metal strip 9, separating cuts 12a, 12b, 12c, 12d which extend in the rolling direction W and run transversely to the rolling direction are arranged. Three sections 12a, 12b, 12c extend in the rolling direction W and connect adjacent, in different The fourth separating cut 12d is arranged transversely to the rolling direction W and connects the two longitudinal cuts 12b, 12c. This cutting pattern 12a to 12d is repeated continuously in the rolling direction W. By this cutting arrangement, the closed gills 11 are separated, and the metal strip 9 'can - as shown in the method section b) - pull apart transverse to the rolling direction W. This separation takes place after the metal strip 9 has passed through the cutting rollers, not shown. By pulling apart on the one hand, an enlarged width B2 of the metal strip 9 'and on the other hand a separation zone of the width T is achieved. The metal strip 9 'is now divided into two sections of width R1 and width R2, which are interconnected by the aforementioned connecting webs 8. The geometric formation of the connecting webs 8 with the legs 8a, 8b takes place by plastic deformation of the metal strip 9 ', wherein each two adjacent pairs of legs 8a, 8b of the metal strip 9' form a rhombus 13. By pulling the metal strip 9 'on the width B2, a thermal barrier or restricted zone of the width T has been created, without material waste. The process sections a) and b) are thus carried out completely without cutting.

Subsequent to the method section b), the metal strip 9 is pleated in the stretched to the width B2 state, d. H. to the finished corrugated fin 1, shown in section c), formed. The corrugated fin 1 can then - as described above - cassetted with the flat tubes 5, 6 and added to a complete heat exchanger block 2, which is then "finished in a shot" soldered in a soldering oven, not shown.

According to a preferred embodiment, the pleating takes place simultaneously with the cutting of the gills. The spreading of the rib is then advantageously then with the help of guide rollers.

Fig. 2 shows in three process sections a), b) and c) the production of a corrugated fin 20, which is shown in the finished and installed state in the picture c). The corrugated fin 20 consists - as in the first embodiment - of two sections 20a, 20b, which has a thermal barrier 21 in the form of two Connecting webs 22, 23 are interconnected. The continuous corrugated fin 20 is part of a Wärmeübertragerblokkes 24 shown only partially, which consists of two Wärmeübertragem, which are represented by a first row of tubes 25 and a second row of tubes 26 - analogous to the previous embodiment. The connecting webs 22, 23 are each composed of two legs, which together form an obtuse angle. Each corrugated fin 20 thus has two connecting webs 22, 23, whose legs form approximately the shape of an X.

The production of the corrugated fin 20 will be described below with reference to the method sections a) and b). In the first method section a) a flat metal strip 27 is shown, which is occupied in a similar manner as in the previous embodiment with gills 28. The metal strip 27 has a left portion 27a and a right portion 27b, in which the distance of the gills transverse to the rolling direction W has the value a, while the distance of the gills 28 in the central region, ie between the sections 27a, 27b to a degree b is enlarged. In this central region of the width b, separating cuts 29 between adjacent gills 28 are introduced transversely to the rolling direction W into the metal strip 27. In addition, between these transverse separating cuts 29 in the rolling direction W extending separating cuts 30 are mounted. The transverse and longitudinal cuts 29, 30 are made during the cutting of the gills by means not shown, known per se cutting rollers. Analogous to the embodiment according to Fig. 1 Here, too, the separating cuts 29, 30 are produced in one operation with the cutting of the gills 28.

The process step b) shows the metal strip 27 'in a state after pulling apart transversely to the rolling direction W. As a result of the separation of the ribbing belt 27 at the interfaces 29, 30 resulting after pulling V-shaped connecting webs 31, 32, 33, wherein the adjacent Connecting webs 32, 33 form a closed rhombus 34. By pulling the ribbed tape 27 from the state a) to the state b), the rib material has been plastically deformed in the region of the connecting webs 31, 32, 33 and thus remains in the pulled-apart Width stand. Subsequently, the metal strip 27 'is pleated, ie formed into the corrugated fin 20. This results in the form shown in the method section c) with two connecting webs 22, 23, wherein the connecting web 23 in section c) corresponds to the connecting web 32 in section b) and the further connecting web 33 after pleating in section c) covered by the connecting web 23 is. Thus, by non-cutting forming, ie waste-free and material-saving production of the distance between the rows of tubes 25, 26 bridged and a thermal barrier 21 are created.

Claims (10)

1. Method for the production of a corrugated fin for a heat exchange block consisting of at least two heat exchangers with at least one row of first tubes for the first heat exchanger and at least one row of second tubes for the second heat exchanger, such that the corrugated fin is formed as a continuous fin arranged between the first and the second tubes with a thermal barrier between the rows of first and second tubes, with slots (11, 28) cut into a metal strip (9, 27), characterised in that in the area of the thermal barrier and between adjacent slots (11, 28) the metal strip (9, 27) is separated and pulled apart transversely to the longitudinal direction W.
2. Method according to Claim 1, characterised in that the metal strip is made as an endless strip, fed between a pair of cutting rolls for cutting the slots and for the separation cuts.
3. Method according to Claim 2, characterised in that the separation is carried out by producing cuts (12a - d; 29, 30) that extend in the rolling direction W and/or transversely to the rolling direction.
4. Method according to Claims 1, 2 or 3, characterised in that the slots (11) are arranged in rows (10) and are spaced an equal distance apart.
5. Method according to Claims 1, 2 or 3, characterised in that the distance b between adjacent slots (28) in a row is increased in the area of the thermal barrier.
6. Method according to Claims 3, 4 or 5, characterised in that the length of the separating cuts (12a- d; 29, 30) is not greater than the length of the slots (11, 28).
7. Method according to any of Claims 1 to 6, characterised in that the pulling apart of the partially separated metal strip (9', 27') produces connecting webs (8, 13; 32, 33, 34) arranged in a diamond shape to form the thermal barrier.
8. Method according to any of the preceding claims, characterised in that the separation cuts and in particular the slots are arranged symmetrically in relation to the thermal barrier zone.
9. Heat exchange block (2) consisting of at least two heat exchangers, each comprising at least one row (3, 4) of tubes (5, 6) and common corrugated fins (1) with slots cut into them between the tubes (5, 6), such that between the rows (3, 4) of the first and the second heat exchanger a gap A is formed, and in the corrugated fins (1) in the area of the gap A and between adjacent slots thermal barriers are arranged, characterised in that the thermal barriers are formed by at least one connecting web (8) obtained by non-cutting deformation and consisting in each case of two arms (8a, 8b) arranged at an angle to one another.
10. Heat exchanger block (2, 24) according to Claim 9, characterised in that the connecting web (8; 22, 23) has a heat-conducting cross-section smaller than that of the corrugated fin (1, 20) and a heat-conducting length larger that the spacing A of the tube rows (3, 4).

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