EP1794528B1 - Heat exchanger, particularly for a motor vehicle - Google Patents

Abstract

The invention relates to a heat exchanger (1) comprising a block (2) consisting of tubes (3) and ribs (4). Said tubes (3) can be flowed through by a first medium in at least one direction and can be flowed around by a second medium. The heat exchanger also comprises at least one collecting and/or distributing device for the first medium that is connected to the tubes (3) in a communicating manner. The invention provides that the collecting and/or distributing device is provided in the form of at least one C-profile (5) with two limbs (5a, 5b) and with a web (5c), and that the C-profile (5) is closed by a strip (7) situated between the limbs (5a, 5b).

Description

The invention relates to a heat exchanger, in particular for a motor vehicle according to the preamble of claim 1 .

By the DE-A 102 60 107 the applicant has a heat exchanger, in particular for a motor vehicle is known, which is characterized by a pressure-stable construction, as it finds particular use in CO2-powered air conditioning. The pipes through which the refrigerant can flow are designed as multi-chamber flat tubes which communicate with collecting and / or distributing devices as well as deflecting devices. The collection and / or distribution facilities are characterized by a pressure-stable plate construction, which essentially consists of a bottom plate, a distribution plate and a cover plate. The refrigerant, R744, is guided in the known heat exchanger in various ways through the tubes, with basically deflections in the width (parallel to the end face) and in the depth (in or against the flow direction of the air) are possible. A disadvantage of this heat exchanger is that the inlet and outlet channels or the refrigerant inlet and outlet are not optimally insulated from each other thermally, but rather are in heat-conducting connection via the common plates.

By the DE-A 199 06 289 a heat exchanger for a CO2 refrigeration cycle was known, in which the refrigerant from the refrigerant inlet to the refrigerant outlet is deflected only in width, so that it flows through the entire heat exchanger block three-flow, ie in three passes. The header boxes, which receive the pipe ends, are divided into two circular cross sections communicating with one another for reasons of internal pressure stability. A deflection of the refrigerant in the depth, ie a cross-counterflow with the air is not provided here, which limits the performance of this heat exchanger.

A similar construction was made by the WO 98/51983 known, wherein a pressure-resistant heat exchanger of flat tubes and manifolds is constructed, which are each constructed of a plurality of communicating circular cross-sections. The headers are manufactured as extruded parts and thus particularly resistant to internal pressure, but also associated with corresponding costs. Again, there is only a deflection of the refrigerant in the width and not in depth.

The WO 03/040640 discloses a heat exchanger with a collecting device, wherein the collecting device is formed as at least one C-profile with two legs and a web and the C-profile is closed by a bar arranged between the legs.

It is an object of the present invention to improve a heat exchanger of the type mentioned, in particular with deflection in the width and / or in depth with respect to its collection and / or distribution facilities, in particular, a thermal separation of flow channels is given with high temperature difference ,

This object is solved by the features of patent claim 1. According to the invention it is provided that the collecting and / or distribution device is designed as at least one C-profile, which is closed by an inserted rake. The C-profile can be supplied as a semi-finished product or folded out of a flat sheet metal. The openings for receiving pipe ends, called passages, can easily pass through Punching or stamping are produced. The rake, ie a bar with recesses in the region of the passages can be formed as a flat stamped part with arbitrary shapes, for. B. with tongue-shaped dividers, which extend into the C-profile and cause a subdivision of the C-profile into individual chambers. The dividers, which act as partitions, can be arranged at any point between the passages. The C-profile is soldered to the rake and the pipe ends and thus represents a low-priced pressure-resistant solution.

In an advantageous embodiment of the invention, two C-profiles are arranged at a distance next to each other for two rows of tubes, d. H. in the air flow direction one behind the other. Due to the distance between the two C-profiles, the advantage of a thermal separation, d. H. Heat is prevented from flowing from the higher temperature C-profile to the lower temperature C-profile, thereby degrading the efficiency of the heat exchanger.

In a further advantageous embodiment of the invention, deflection devices are provided on the side facing away from the C-profiles side of the block, which are preferably formed as a U-profile with an inserted wave profile, wherein in each case a "wave" forms a deflection chamber and two pipe ends together. Thus, a deflection in the depth, preferably against the air flow direction, d. H. be effected to generate a countercurrent. The first flow medium, preferably carbon dioxide, therefore, initially enters a leeward C-profile, flows through a leeward row of pipes or leeward arranged flow channels, is deflected by the deflection opposite to the air flow direction and flows through a windward pipe row or flow channels until reaching the windward C-profile, where the refrigerant meanwhile has a considerably lower temperature than when entering. Due to the distance between the two C-profiles according to the invention, heat from the leeward C-profile can not flow to the windward C-profile and heat the refrigerant there again. This thermal separation thus has a particularly advantageous effect on gas coolers with falling or sliding temperature of the supercritical refrigerant. The lee- and windward flow channels can be used as separate rows of tubes, z. B. be formed two rows of flat tubes or as a continuous flat tube with opposite flow-through flow channels.

In a further embodiment of the invention, the C-profile can also be used as a deflection by a bar between two legs is inserted, which may have either the shape of a rake or a plate with slots. The slots are formed as slots and include the tube ends - they form in a double-row tube assembly a transfer channel from one to the other row of tubes.

In a further advantageous embodiment of the invention, stops for limiting the insertion depth of the tubes are provided on the strips, rakes or plates, and preferably designed as paragraphs, which engage over the pipe ends, preferably on the narrow sides thereof. Thus, the tubes can be mounted in a simple manner always with the same insertion depth.

In a further advantageous embodiment of the invention may be arranged in the bar, in particular the plate, communicating with the slots, a collecting channel for escaping from the tubes refrigerant. Thus, a parallel connection of the tubes, be it possible for a two-row or a single-row arrangement.

In a further embodiment of the invention, both C-profiles can be divided by arranged on the rake dividers in two chambers, so that four chambers result for the entire heat exchanger, of which two are approximately diagonally opposite chambers connected by a transfer device. This results in the advantage that the heat exchanger can be flowed through twice, in each case half-side in countercurrent. This increases the heat transfer efficiency. It is also possible to create several chambers through several dividers, which are connected by a plurality of crossing means.

In a further advantageous embodiment of the invention, the transfer means each have a breakthrough in the web portion of the C-profile and a Übertrittsteil which forms a connection or transfer channel between the two C-profiles. The refrigerant thus enters the first leeward located chamber, flows through after deflection in depth the second luvseitig arranged chamber, then enters the third leeseitig located chamber and leaves the heat exchanger on the fourth luvseitig located chamber of the windward C-profile - so are refrigerant inlet and - exit approximately diagonally opposite, ie they are largely thermally isolated from each other (a thermally conductive connection exists only in the middle crossing area).

The soldered heat exchanger according to the invention can be used advantageously in particular as a gas cooler of a CO2 air conditioning system because the collecting, distributing and deflecting devices according to the invention are on the one hand pressure-resistant and on the other hand variable in terms of flow guidance and thus permit deflections of the refrigerant both in the width and in the depth, whereby an effective cooling of the refrigerant from entry to exit is possible.

Fig. 1

einen Ausschnitt eines Gaskühlers mit C-Profil und eingesetztem Rechen,

Fig. 1 a

einen Abschnitt eines Rechens mit Trennsteg,

Fig. 2

einen Querschnitt durch den Gaskühler mit zwei C-Profilen und Übertrittsbereich,

Fig. 3

eine Ansicht von oben auf die C-Profile mit Übertrittsbereich,

Fig. 4

einen Ausschnitt des Gaskühlers mit Umlenkeinrichtung,

Fig. 5

eine alternative Form einer Umlenkeinrichtung mit C-Profil und Rohreinstecktiefenbegrenzung,

Fig. 6

einen Schnitt durch eine weitere Umlenkeinrichtung mit Rohreinstecktiefenbegrenzung und Sammelkanal,

Fig. 7

ein einreihiges System mit C-Profil und Rechen und

Fig. 8

ein einreihiges System mit C-Profil und Schlitzplatte.

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

Fig. 1

a section of a gas cooler with C-profile and inserted rake,

Fig. 1 a

a section of a rake with divider,

Fig. 2

a cross section through the gas cooler with two C-profiles and crossing area,

Fig. 3

a top view of the C profiles with crossing area,

Fig. 4

a section of the gas cooler with deflection,

Fig. 5

an alternative form of a deflection device with C-profile and Rohrinstecktiefenbegrenzung,

Fig. 6

a section through another deflection with Rohrinstecktiefenbegrenzung and collecting channel,

Fig. 7

a single-row system with C-profile and rake and

Fig. 8

a single-row system with C-profile and slotted plate.

Fig. 1 shows a section of a gas cooler 1 with a gas cooler block 2, consisting of flat tubes 3 and arranged between them corrugated fins 4. The flat tubes 3 are arranged in two rows and soldered to the corrugated fins 4. On a series of flat tubes 3, a C-profile 5 is attached, which has elongated openings 6, so-called passages, for receiving the tube ends of the flat tubes 3. In the open side of the C-profile is a Rake 7 used, which has in the region of the passages 6 recesses 7a for the pipe ends and a divider 7b. The C-profile 5 has two legs 5a, 5b formed as flat sides, which are connected by a web 5c. The C-profile can be made by folding from a flat sheet, with the passages 6 can be produced by stamping before folding.

Fig. 1a shows the rake 7 (partially) as a single part with the divider 7b, as he also in Fig. 1 is shown. The C-profile, which is soldered to the tube ends of the flat tubes 3 and the rake 7, forms a collection or distribution channel, which is interrupted by the divider 7b. Thus, two or more chambers can be formed within the C-profile. The C-profile 5 is closed at the end by an end web 7 c at the end of the rake 7.

Fig. 2 shows a cross section in the upper region of the gas cooler 1 with a first row of tubes I and a second row of tubes II. The air flow direction is shown by an arrow L; Thus, the row of tubes I is the leeward (downstream) and the tube row II, the windward (upstream). On the windward tube row II, the C-profile 5 and on the leeward tube row I is another C-profile 8 is arranged, which is also completed by a rake 9 to the outside and mirror image of the C-profile 5 with 7 rake. Both C-profiles form flow channels 10, 11, which are interconnected by a transfer channel 12. Between both C-profiles 5, 8 there is a distance a, in which a T-shaped formed transition part 13 is inserted and soldered to the two C-profiles 5, 8. The crossing channel 12 is - as shown in the drawing - formed by openings in the web areas of the C-profiles 5, 8 and the T-shaped crossing part 13. Such a transition region is preferably arranged in the middle of the heat exchanger or in the middle region of the two C-profiles 5, 8, so that a passage of the refrigerant from the windward chamber 10 into the leeward chamber 11 is made possible. Depending on the number of deflections of the refrigerant in the depth, a plurality of such transition areas can also be provided on a heat exchanger.

Fig. 3 shows the crossing area according to Fig. 2 in a view from above of the two C-profiles 5, 8, which are cut in the region of their webs 5c, 8c. The distance a between the two C-profiles 5, 8 causes a thermal decoupling. The front C-profile 5 is divided by the divider 7b of the rake 7 in two flow chambers 10, 14 and the rear C-section 8 through a divider 9b of the rake 9 in two flow chambers 11, 15. The two separating webs 7b, 9b are arranged offset to one another, so that an overlap is formed between the chambers 10, 11, within which the transfer channel 12 is arranged, which is formed in the region of the distance a through the T-shaped transition part 13. Thus, there is a Z-shaped flow deflection of the refrigerant from the chamber 10 into the chamber 11. The flow chamber 15 is the inlet chamber for the refrigerant and the flow chamber 14, the outlet chamber for the refrigerant from the gas cooler 1. The refrigerant inlet, not shown, and also not shown refrigerant outlet are thus almost diagonally opposite and have a maximum distance, which proves favorable for the efficiency of the gas cooler, in particular in conjunction with the thermal decoupling by the distance a of both C-profiles 5, 8th

Fig. 4 shows the C-profiles 5, 8 opposite side of the gas cooler 1 with a deflection device 16, which consists essentially of a U-profile 17 with a wave profile 18. The U-profile 17 has a flat web portion 17a, which acts as a tube sheet and has punched passages 19 for receiving the tube ends of the flat tubes 3. On both sides of the tube bottom 17a, U-legs 17b, 17c are bent at right angles, which receive the wave profile 18 between them and are soldered tightly thereto. The wave profile 18 has a multiplicity of "waves" 18a, 18b..., Which respectively form deflection chambers and communicate with tubes of the first and second tube rows I, II. The wave profile 18 is on the one hand end face with the two legs 17b, 17c soldered and on the other hand with its not shown wave crests with the tube sheet 17a. By this deflection 16 thus a deflection in the depth is effected.

The embodiment described above represents only one possibility of many for the flow guidance of the refrigerant within the gas cooler 1 according to the invention Figures 2 and 3 omitted transfer area omitted, so that both C-profiles 5, 8 are not connected to each other on the refrigerant side, but are completely separate. The arrangement of the separating webs could be modified, for example, to the effect that only the leeward rake 9 has an approximately central separating web 9b, while the windward rake 7 has no separating web. This would mean that the refrigerant, which enters the inlet chamber 15, reaches the second chamber 10 after deflection by the deflection device 16 and would then be distributed to the chamber 14. After the deflection in the depth of the deflection 16 so would be done by the flow from the chamber 10 into the chamber 14, a deflection in the width. After renewed deflection at depth, now in the air flow direction L, the chamber 11 would be reached by the refrigerant, which would now be the exit chamber. Other flow guides in the invention are possible.

Fig. 5 shows a further embodiment of a deflecting device 20, which is designed as a C-profile 21 with two parallel legs 21a, 21b and a web 21c. Between the two legs 21 a, 21 b, a plate 22 is inserted, which has slots 23 in the form of slots. Within the slots open pipe ends 24, 25, which are through the lower leg 21 a, which acts as a tube sheet, are pushed through. The block of the heat exchanger, consisting of tubes and fins, is not shown here. At the leg 21 a facing side of the plate 22 paragraphs 26, 27 are arranged, which partially overlap the tube ends 24, 25 on their narrow sides and thus act as a limitation for the insertion depth of the tubes. The elongated holes 23 form a transfer channel for the tubes 24, 25 or the first and the second row of tubes. The assembly of the deflecting device 20 takes place in such a way that first the plate 22 is pushed into the gap between the two legs 21 a, 21 b and fixed in this position, which can be done positively or non-positively. Thereafter, the deflection device 20 is attached to the tube ends 24, 25 of the finished block, not shown, wherein the tube ends 24, 25 come with their upper edges in attack with the paragraphs 26, 27. Thereafter, the heat exchanger can be soldered.

Fig. 6 shows a further embodiment of a deflecting device 28 in a sectional view. The C-profile 29 is shown here by dashed lines. Within the profile 29 is a plate 30, which on its underside four paragraphs 31a, 31b, 31c, 31d, which each overlap the narrow side upper edges of the two flat tubes 32, 33 and thus form a Einstecktiefenbegrenzung. Above the tubes 32, 33 in the plate 30, two slots 34, 35 and above a perpendicular to the plane extending collection channel 36 for emerging from the tubes 32, 33 in the direction of the arrows P refrigerant arranged. This arrangement with collecting channel 36 allows a parallel flow of the tubes 32, 33, ie in the same direction, as shown by the arrows P. The exiting refrigerant is then supplied via the collecting channel 36 to the outlet of the heat exchanger.

Fig. 7 shows a heat exchanger 37 as a single-row system, ie with only one row of flat tubes 38, which are received by the lower leg 39 a of the C-profile 39. In the C-profile 39 is a rake 40 - as described above - inserted. The plate-shaped rake 40 has on its underside a shoulder 41 which engages over the narrow side of the pipe end 38 and thus forms a stop for (one-sided) limitation of the insertion depth. Laterally, the heat exchanger 37 can be completed by side parts, not shown, which are inserted with their ends by slots, not shown in the C-profile 39.

Fig. 8 shows a further embodiment of a single-row heat exchanger 42 with C-profile 43 and inserted plate 44, which has 45 slots in the form of slots 46 in the pipe ends. In the area of the narrow sides of the pipe ends 45 are paragraphs 47, 48 provided as a double-sided Einstecktiefenbegrenzung.

The invention is not limited to the refrigerant R747 (CO2), but also extends to heat exchangers, which are operated with the refrigerant R134a or R152.

Claims (27)

1. Heat exchanger (1) comprising a block (2) consisting of tubes (3) and in particular of fins (4), wherein a first medium can flow through the tubes (3) in at least one direction and a second medium can flow around the tubes (3), and comprising at least one collecting and/or distributing device for the first medium, which is connected to the tubes (3) for communication, the collecting and/or distributing device being designed as at least one C-section (5) with two legs (5a, 5b) and a web (5c) and the C-section (5) being closed by a strip (7) disposed between the two legs (5a, 5b), characterised in that openings (6) for the accommodation of tube ends of the tubes (3) are provided in one of the legs (5b).
2. Heat exchanger according to claim 1, characterised in that the strip is designed as a rake (7) with recesses (7a) in the region of the openings (6) for the tube ends.
3. Heat exchanger according to claim 1 or 2, characterised in that the tubes (3) have two or more rows (I, II) of tube ends and in that each row (I, II) is joined to a C-section (5, 8).
4. Heat exchanger according to claim 3, characterised in that the two C-sections (5, 8) are arranged parallel to and at a distance (a) from each other.
5. Heat exchanger according to claim 3 or 4, characterised in that one C-section (5) is designed as an inlet passage and the adjacent C-section (8) is designed as an outlet passage, and in that medium can flow in parallel through the tubes (3) in two directions with a deflection in depth.
6. Heat exchanger according to claim 3, 4 or 5, characterised in that the tube ends remote from the C-sections (5, 8) are connected to a deflecting device (16, 20, 28).
7. Heat exchanger according to claim 6, characterised in that the deflecting device (16) is designed as a U-section (17) with a web (17a) representing a tube sheet for the accommodation of the tube ends and with two side surfaces (17b, 17c) between which a corrugated baffle plate (corrugated profile 18) is disposed.
8. Heat exchanger according to claim 7, characterised in that the corrugated profile (18) has ridges joined to the tube sheet (17a) to form deflection chambers.
9. Heat exchanger according to claim 6, characterised in that the deflecting device (20, 28) is designed as a C-section (21, 29) into which a strip (22, 30) can be inserted.
10. Heat exchanger according to claim 9, characterised in that the strip is designed as a rake.
11. Heat exchanger according to claim 9, characterised in that the strip is designed as a plate (22) with slots, in particular elongated holes (23), into which the tube ends (24, 25) terminate.
12. Heat exchanger according to claim 9, 10 or 11, characterised in that the strip (22, 30) is provided with stops (26, 27, 31a - 31d) for limiting the insertion depth of the tubes (24, 25, 32, 33).
13. Heat exchanger according to claim 12, characterised in that the stops are designed as shoulders (26, 27, 31a - 31d) in the strip (22, 30), which partially overlap the tube ends (24, 25, 32, 33).
14. Heat exchanger according to claim 13, characterised in that the shoulders (26, 27, 31a - 31d) are disposed in the region of at least one of the narrow sides of the tubes (24, 25, 32, 33).
15. Heat exchanger according to any of claims 9 to 14, characterised in that the strip (30) is provided with a collecting passage (36) for refrigerant discharged from the tubes (32, 33).
16. Heat exchanger according to any of the preceding claims, in particular claim 16, characterised in that the tubes are arranged in a single row or in two rows (32, 33) and in that medium can flow through them in parallel.
17. Heat exchanger according to any of claims 2 to 16, characterised in that at least one C-section (5) is subdivided in the longitudinal direction by one or more separating webs (7b) provided on the rake (7).
18. Heat exchanger according to claim 17, characterised in that both C-sections (5, 8) are subdivided in the longitudinal direction to form four or more chambers (10, 11, 14, 15) and in that two chambers (10, 11) are connected by a flow-over passage (12) between the C-sections (5, 8).
19. Heat exchanger according to claim 18, characterised in that the flow-over passage (12) is represented by a through hole in the webs (5c, 8c) and by a flow-over part (13) between the webs (5c, 8c).
20. Heat exchanger according to claim 19, characterised in that the flow-over part (13) is T-shaped and has a T-web with through openings and in that the T-web bridges the distance a between the C-sections (5, 8).
21. Heat exchanger according to any of claims 1 to 20, characterised in that the first medium is a refrigerant, in particular R744 (CO2), and the second medium is a gas, in particular air.
22. Heat exchanger according to claim 21, characterised in that the heat exchanger is designed as a gas cooler (1) of a CO2-operated air conditioning system.
23. Heat exchanger according to claim 21 or 22, characterised in that the CO2 refrigerant and the air are routed in a multiple path arrangement.
24. Heat exchanger according to any of the preceding claims, characterised in that it can be produced in a soldering process.
25. Heat exchanger according to any of claims 19 to 24, characterised in that the flow-over part (13) is tubular.
26. Heat exchanger according to any of claims 19 to 25, characterised in that the flow-over part (13) projects into at least one of the C-sections.
27. Heat exchanger according to any of the preceding claims, characterised in that in at least one of the C-sections a chamber is formed which connects the tubes of a first flow-through direction to tubes having a second flow-through direction differing from the former, the first and second flow-through directions being in particular opposed to each other.

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