EP1042641B1 - Heat exchanger tubular block and a multi-chamber flat tube which can be used therefor - Google Patents

Description

The invention relates to a heat exchanger tube block according to the preamble. of claim 1 and a multi-chamber flat tube that can be used for such a tube block. Such a heat exchanger tube block is already known from DE-A-196 49 129.

The tube block contains a plurality of block units each consisting of a plurality of tube units lying one above the other in a stack, the stacking direction defining a block vertical direction and the flow channels formed by the tube units running in a block transverse direction perpendicular thereto. The block units are arranged one behind the other in the block depth direction perpendicular to the block vertical and block transverse directions. The pipe units open into collecting ducts which are arranged laterally on the block in the vertical direction of the block, ie with a longitudinal axis parallel to this. In the present case, the term "collecting channels" is used uniformly for the sake of simplicity for all channels into which the pipe units open, these being collecting channels in the actual sense in which the medium, which is carried out in parallel through several pipe units, is collected for the purpose of being discharged from the pipe block Distribution channels in which the medium supplied to the pipe block is distributed to several pipe units that flow into it as well as deflection channels, in which the medium is deflected from a first group of pipe units opening into a second group of pipe units opening.

In use, a first medium flows through the tube block, while a second medium to be brought into thermal contact with the first is passed over the tube block in the depth direction of the block with the flow against the outside of the tube block surfaces. Heat exchangers with such tube blocks are e.g. used as evaporators and condensers in automotive air conditioning systems. The pipe block is usually supplemented into a pipe / fin block by inserting heat-conducting corrugated fins between the pipe units. The tube units can be formed, for example, from flat tubes.

A generic heat exchanger tube block is disclosed in the published patent application DE 39 36 101 A1. The tube block there is made up of single-chamber flat tubes which are bent once or in a meandering shape several times in a U-shape by 180 ° in the plane of their transverse and longitudinal extension and are stacked one above the other in the direction perpendicular thereto with the interposition of corrugated fins. Depending on the number of flat tube turns, the tube block thus consists of two or more block units located one behind the other in the block depth direction, each of which contains a stack of straight, parallel flowed flat tube sections. Adjacent block units are in serial fluid communication via the side U-bends of the flat tubes. The two ends of each flat tube open out on the same block side into an associated collecting duct running along the vertical direction of the block, the two collecting ducts being formed by a longitudinally divided collecting box or two separate collecting pipes.

The invention is a technical problem of providing a heat exchanger tube block of the aforementioned. Type with which a heat exchanger with high heat transfer capacity and high pressure stability with a relatively small filling quantity and can be realized with the possibility of variable guidance of the temperature control medium passed through, as well as a multi-chamber flat tube which is particularly suitable for the construction of such a tube block.

The invention solves this problem by providing a heat exchanger tube block with the features of claim 1 and a multi-chamber flat tube with the features of claim 10.

In the heat exchanger tube block according to claim 1, at least one collecting duct connection is provided between at least two adjacent block units, which connects a collecting duct of the one block unit directly to a collecting duct of the other block unit. The term "direct" means that the relevant collecting channels are connected via a corresponding fluid connection running in the block depth direction and not or at least not only via one or more of the pipe units of the block. With the help of these one or preferably several direct fluid connections of the collecting channels arranged on the side of the tube block, a very variable flow control of the medium passed through, adapted to the respective application, for example a refrigerant of an air conditioning system, can be realized. A high heat transfer capacity for the pipe block can be achieved by the several block units lying one behind the other in the block depth direction and thus the flow direction of the other medium passed over the pipe block. The tube block can be constructed from extruded flat tubes with channels optimized with regard to a small filling quantity, ie a small volume of the tube block to be flowed through, and high pressure stability. The collecting ducts arranged on the side of the pipe block can be formed by highly pressure-stable collecting pipes with a relatively small cross-section, in particular if correspondingly narrow flat pipe units or those with the longitudinal direction of the collecting duct flat tube ends turned out from the transverse plane can be used.

In a tube block developed according to claim 2, direct collecting channel connections between each pair of adjacent block units are provided in such a way that the associated temperature control medium flows through the block units in series.

In a tube block developed according to claim 3 is a collecting space, which e.g. is formed by a collecting pipe or a collecting box, divided into several collecting channels by transverse partition walls. This allows a serpentine flow, once or several times deflected, to flow through a respective block unit.

In a tube block developed according to claim 4, the collecting channels are formed on at least one block side by individual collecting tubes, each assigned to a block unit, which are spaced apart in the depth direction of the block, which e.g. when used in an evaporator, the condensate drainage easier. The spacing is brought about by one or more spacer elements which are formed on or attached to the header tubes.

In further refinements of this measure, the spacer element according to claim 5 includes a deformed sheet metal piece or tube piece with at least one slot opening or according to claim 6 an outwardly bulged passage on a collecting tube. The spacer elements designed in this way keep the manifolds at a distance and at the same time define a respective manifold connection. In a further embodiment of the invention according to claim 7, the spacer element can consist of two passages which abut or engage in one another in a fluid-tight manner, for which purpose at least one of the two passages is bulged outwards.

In a tube block further developed according to the invention, the tube units are formed by straight flat sections which open into the header tubes with twisted tube ends. Due to the twisting at the end, the flat tube ends are turned out of the transverse plane of the header tubes, which makes it possible to use header tubes with an inner diameter that is smaller than the width of the flat tube, in order to keep the inner volume of the tube block low.

A tube block developed according to claim 9 is supplemented to a tube / fin block. For each corrugated fin layer, a single corrugated fin can be introduced, the width of which essentially corresponds to the entire block depth, or several corrugated fins are provided next to one another, which can be of the same or different width and structure.

In the case of a tube block developed according to the invention, at least two tube units lying next to one another in the depth direction of the block are realized as integral parts of a one-piece multi-chamber flat tube, for which purpose the width extends over a corresponding number of block units.

The multi-chamber flat tube according to claim 10 is divided at the end by one or more longitudinal slots into a plurality of separate end segments, each of which is twisted about its own longitudinal axis. In the case of a tube block constructed from such flat tubes, the end segments of each flat tube end region are then individually assigned to the corresponding block units, so that the chambers of each flat tube are divided into groups on the corresponding block units, the chambers emanating from an end segment each belonging to a block unit.

Fig. 1

eine schematische Seitenansicht einer von mehreren Blockeinheiten eines Rohr-/Rippenblocks für einen Verdampfer einer Klimaanlage,

Fig. 2

eine schematische Seitenansicht einer seitlichen Sammelrohranordnung des Rohr-/Rippenblocks von Fig. 1,

Fig. 3

eine schematische Querschnittsansicht einer ersten Realisierung direkter Fluidverbindungen zwischen Sammelkanälen der Sammelrohre von Fig. 2,

Fig. 4

eine schematische Querschnittsansicht einer zweiten Realisierung der Sammelkanalverbindungen,

Fig. 5

eine schematische Querschnittsansicht einer dritten Realisierung der Sammelkanalverbindungen,

Fig. 6

eine schematische Querschnittsansicht einer vierten Realisierung der Sammelkanalverbindungen und

Fig. 7

eine schematische, teilweise Draufsicht auf ein für den Rohr-/Rippenblock von Fig. 1 verwendbares Mehrkammer-Flachrohr.

Advantageous embodiments of the invention are shown in the drawings and are described below. Here show:

Fig. 1

1 shows a schematic side view of one of a plurality of block units of a tube / fin block for an evaporator of an air conditioning system,

Fig. 2

FIG. 1 shows a schematic side view of a lateral manifold arrangement of the tube / fin block from FIG. 1,

Fig. 3

2 shows a schematic cross-sectional view of a first realization of direct fluid connections between collecting channels of the collecting pipes of FIG. 2,

Fig. 4

1 shows a schematic cross-sectional view of a second realization of the collecting duct connections,

Fig. 5

2 shows a schematic cross-sectional view of a third realization of the collecting duct connections,

Fig. 6

is a schematic cross-sectional view of a fourth implementation of the manifold connections and

Fig. 7

is a schematic, partial plan view of a multi-chamber flat tube usable for the tube / fin block of FIG. 1.

1 shows a tube block unit 1, several of which are arranged one behind the other in the block depth direction, that is to say perpendicular to the plane of the drawing, and thereby form a tube / fin block which can be used, for example, as a parallel-flow evaporator with variable refrigerant guidance in a motor vehicle air conditioning system. The respective block unit 1 contains a stack of multi-arm flat tube units 2 successive in the block vertical direction, ie stacked one above the other, whose chambers, ie flow channels, in Block cross direction, ie perpendicular to the block depth and block vertical direction. In their end regions 3a, 3b, the flat tube units 2, which are otherwise located in planes perpendicular to the block vertical direction, are twisted by a predeterminable torsion angle about their longitudinal central axis, alternatively about an axis parallel to them. The torsion angle can be selected as desired between 0 ° and 90 °, with a torsion of 90 ° being selected as an example in FIG. 1. Heat-conducting corrugated fins 6 are introduced between the flat tube units 2.

With their twisted ends 3a, 3b, the flat tube units 2 open into respective header tubes 4a, 5a provided on opposite tube block sides, which are arranged with a longitudinal axis parallel to the vertical direction of the block. The flat tube ends 3a, 3b are inserted in a fluid-tight manner in corresponding slots in the collecting tube 4a, 5a. In the case of pipe ends twisted by 90 °, these longitudinal slots run parallel to the longitudinal axis of the collecting pipe, which enables the use of collecting pipes 4a, 5a with a particularly small inside diameter. In extreme cases, the latter then only needs to be slightly larger than the thickness of the flat tube units 2. Depending on requirements, the longitudinal slots made on the respective manifold 4a, 5a are separated from one another by narrow webs or are combined to form a continuous longitudinal slot.

FIG. 2 shows an arrangement of four collecting channels 4a, 4b, 4c, 4d lying next to one another in parallel in the block depth direction, as are provided on the right side of the tube block in FIG. 1 for the assumed case that the tube block is composed of four block units 1 lying one behind the other. On the opposite side of the tube block, four header tubes are then also correspondingly arranged. The side shown in FIG. 2 forms the connection side of the pipe block, the medium passed through the pipe block for the flow direction selected in FIGS. 1 and 2, illustrated by flow arrows, being fed to the left-hand header pipe 4a in FIG. 2 and from the one shown in FIG right manifold 4d is discharged again. It is understood that alternatively the opposite flow direction is possible. The manifolds 4a to 4d shown in FIG. 2 are each separated by a transverse partition 7a to 7d into two separate manifolds 8a, 8b; 9a, 9b; 10a, 10b; 11a, 11b divided. In contrast to this, the opposite collecting pipes are undivided and therefore each form a single collecting channel 12, as illustrated in FIG. 1 on the left collecting pipe 5aa. This has the consequence that the undivided manifolds on the left side of the block in FIG. 1 act as deflecting tubes which deflect the one part of the flat tube units, which open in parallel on the opposite side into the one collecting duct 8a, into the other part of the flat tube units, which open opposite to the other collecting channel 8b. This flow behavior can also be seen in FIG. 1.

To transfer the flow medium from one block unit to another, i.e. To connect the block units in terms of flow technology, a collection channel connection 13a, 13b, 13c is provided between each two adjacent ones of the four header pipes 4a to 4d of FIG. 2, in which a direct fluid connection is created in the block depth direction between the associated flow channels. The collecting duct connections 13a to 13c, as can be seen from FIG. 2, are arranged alternately such that of the two collecting ducts of each inner collecting pipe 4b, 4c, one with the neighboring collecting duct of a collecting pipe adjoining on one side and the other with the adjacent collecting duct of a collecting pipe adjoining on the other side is connected. In this way, the temperature control medium is guided serially through the block units located one behind the other, whereby it flows through each block unit in a meandering manner.

In the flow course shown in FIGS. 1 and 2, the temperature control medium reaches the associated collecting duct 8a of one end via a lateral inlet opening 14 Manifold 4a. This collecting duct 8a acts as a distributor, which divides the medium into the first part of parallel flat tube units 2 of the block unit 1 in question that flows into it. After flowing through this group of flat tube units 2, the medium reaches the opposite collecting or deflecting tube 5a, where it is deflected in the remaining part of the flat tube units 2 of this block unit 1, in order to pass through these flat tube units into the other collecting channel 8b of the inlet-side collecting tube 4a stream. From there, the medium is forwarded via the corresponding collecting duct connection 13a into the adjacent collecting duct 9a of the adjacent collecting pipe 4b and thus to the next block unit. It flows through this block unit, as can be seen from FIGS. 1 and 2, in the opposite direction to the flow through the first block unit on the inlet side. The flow directions are further illustrated in Fig. 2 in that in those collecting channels in which the temperature control medium is passed into the plane of the drawing, the usual crossed circles are shown, while in the other collecting channels, which act as collectors and into which Medium enters the drawing plane from behind, the usual dotted circles are shown. After flowing through the second block unit, the medium thus arrives in the collecting collecting duct 9b of this block unit and is forwarded from there to the distributing, neighboring collecting duct 10a via the corresponding collecting duct connection 13b to the next block unit. This third block unit is then again flowed through in the same direction as the first block unit. From its collecting channel 10b, the medium reaches the fourth block unit via the associated channel connection 13c, which in turn flows through in the same way as the second block unit. From the collecting manifold 11b of the fourth block unit, the temperature control medium is then discharged from the pipe block via an end outlet 15.

It goes without saying that, as an alternative to the example shown, fewer or more than four block units can also be connected in series in the manner described. Furthermore, it goes without saying that the shape and positioning of the inlet and outlet openings can be modified as desired in relation to the example shown in order to supply the temperature control medium to the pipe block in a manner which is best adapted to the respective application and to discharge it again from there. As a further alternative, additional transverse partition walls can be provided in the collecting tubes on both sides of the respective block unit in order to guide the temperature control fluid through the block unit in a meandering manner with repeated reversal of direction. Another modification is to provide the inlet and outlet openings not on the same as shown, but on opposite pipe block sides.

As indicated in the schematic view of Fig. 2, the manifolds 4a to 4d are spaced apart on the respective pipe block side, which e.g. when used as an evaporator, the condensate drainage easier. This is achieved with spacer elements 16a, 16b, 16c, which simultaneously provide the direct collecting channel fluid connections 13a, 13b, 13c. Various implementations for this are shown in FIGS. 3 to 6. In the example of FIG. 3, a suitably shaped sealing sleeve 17 is provided as a spacer element, which is provided at two radially opposite points on its circumference with longitudinal slots 18a, 18b, the slot edges of which form connecting pieces which are inserted in fluid-tight manner into corresponding longitudinal slots of two header pipes 19a, 19b to be connected are. The tubular sleeve 17, which thus forms a tubular transition piece, is closed at the end and fixes the two fluid-connected header tubes 19a, 19b at the desired distance.

In the example of FIG. 4, a suitably shaped, solder-plated sheet metal piece 20 serves as a spacer element, into which an opening 21 is made, which is adjacent with longitudinal slots 22, 23 Collecting tubes 24, 25 form a continuous fluid connection between the collecting channels defined by the collecting tubes 24, 25. Furthermore, two flat tubes 2a, 2b of adjacent tube block units are shown in FIG. 4, which are inserted with correspondingly twisted tube ends into corresponding longitudinal slots of the header tubes 24, 25 in a fluid-tight manner. As indicated by corresponding flow arrows, the temperature control medium flows from a flat tube 2a and possibly further parallel flat tubes of the same block unit into the collecting duct of the associated collecting tube 24 and is forwarded via the direct collecting channel connection into the collecting channel of the adjacent collecting tube 25 and then into the flat tubes opening there 26 of the next tube block unit concerned.

The solder-plated sheet metal piece 20 is fixed to the manifolds 24, 25 by a suitable soldering process, the previous solder-plating being carried out by any conventional method, e.g. by galvanizing or the so-called CD process. In this case, a common soldering process can be provided both for connecting the spacer elements 20 to the header tubes 24, 25 and for the fluid-tight connection of the flat tube units to the header tubes 24, 25, for which purpose the flat tubes and / or the header tubes are also prefabricated with solder and provided with flux. Alternatively, unplated manifolds 24, 25 can be used and separate shaped solder parts can be introduced at the connection points. The fluid-connected manifolds 24, 25 are also kept at a desired distance from one another with the spacer elements 20 used in the example of FIG. 4.

5 and 6 show examples in which the spacer elements are formed by corresponding bulges on the connected manifolds themselves. In the embodiment of FIG. 5, collecting tubes 26, 27 are used, which are provided with dome-shaped bulges 28, 29 at the connection points are, which surround a respective through opening 30, 31. The header pipes 26, 27 to be connected are joined together with their dome-shaped bulges 28, 29 in a fluid-tight manner, so that the desired fluid connection is obtained on the one hand and the header pipes 26, 27 are kept apart as desired in the area outside the connection point.

In the example of FIG. 6, header pipes 32, 33 to be connected to one another are provided with different, intermeshing dome-shaped bulges 34, 35, which surround associated through openings. The narrower bulge 35 is inserted into the corresponding bulge 34 of greater width and fixed in it in a fluid-tight manner, preferably by means of sealing soldering.

In all of the examples described, in the prefabrication of the required manifolds, the slots required for inserting the tube units can be made in one operation with the slots required for the direct manifold fluid connection, i.e. Passages, and possibly the associated dome-shaped bulges are generated. The passages for the direct collecting channel fluid connections can be round or elongated. The two dome-shaped bulges forming a respective collecting channel-fluid connection do not need, as in the examples shown, both to be bulged outwards; alternatively, one of the two can be bulged inwards, in which the other bulge facing outwards engages.

As indicated in FIG. 4, the flat tube units 2 of the tube / fin block of FIG. 1 can consist of flat tubes 2a, 2b lying next to one another in the block depth direction, for each block unit 1, ie in this case each block unit 1 consists of a stack of individual flat tubes, whose width corresponds essentially to the depth of the respective block unit. Alternatively, a wider flat tube type in one Be used as shown in Fig. 7 schematically and in sections. The multi-chamber flat tube 2c shown there has a width T which essentially corresponds to the total tube block depth, ie the sum of the depths of the individual block units. The flat tube 2c is provided in both end regions, one of which is shown in FIG. 7, with a predeterminable number n of longitudinal saw cuts 36 ₁ , 36 ₂ , 36 ₃ , that is to say n = 3 cuts in this example, as a result of which the end region is divided into one Number n + 1 of end segments 37 ₁ to 37 ₄ , that is, divided into four segments in the case shown. Each end segment 37 ₁ to 37 ₄ is twisted by 90 ° about its own longitudinal central axis, alternatively a different torsion angle greater than 0 ° and less than 90 ° can be selected. In the case of right-angled twisting, the end segments 37 ₁ to 37 _{4 run} on their end faces parallel to the vertical direction of the block, ie to the longitudinal direction of the associated manifolds 38 ₁ , 38 ₂ , 38 ₃ , 38 ₄ , which are provided with corresponding longitudinal slots into which the end segments 37 ₁ to 37 _{4 are} inserted. In this way, the flat tube 2c is fluidically divided into a corresponding number n of flat tube strands 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ , each of which belongs to one of the block units lying one behind the other in the block depth direction and contains an associated subgroup of all flow channel-forming chambers of the flat tube 2c. While in the example of FIG. 7 the flat tube 2c is divided into sub-strands 2 ₁ to 2 _{4 of the} same width, a division into sub-strands of different widths can alternatively be provided. In the example of FIG. 7, an open flow channel 39 remains between two adjacent flat tube parts, in that this is shortened at the end by the correspondingly wide saw cuts 36 ₁ , 36 ₂ , 36 ₃ and thus does not function as a fluid-carrying channel opening into the collecting tubes. If, alternatively, the saw cuts are made as narrow cuts between adjacent channels, all chambers of the flat tube 2c can function as fluid-conducting flow channels if required.

The multi-chamber flat tube 2c is preferably manufactured as an extruded profile with channels optimized with regard to a small internal volume and high pressure stability. To achieve a low internal volume and a high pressure stability of the tube / fin block overall, as mentioned, additionally contributes to the fact that collecting tubes with a relatively small inner diameter can be used for the tube block, especially in flat tubes with twisted ends. In addition, depending on the positioning of the direct collecting duct connections between the collecting pipes and / or the transverse partition walls in the collecting pipes, a very variable flow guidance for the temperature control medium passed through can be achieved.

To form the corrugated fin structure 6 of the tube / fin block, a corrugated fin extending over the entire block depth or a plurality of narrower corrugated fins of the same or different width can be introduced adjacent to one another per fin layer. For example, a wide corrugated fin extending over three block units and a narrow corrugated fin limited to the fourth block unit or alternately a narrower and a wider corrugated fin each can be provided. The various possibilities for introducing the corrugated fins 6 are independent of whether the wide flat tube 2c from FIG. 7 or a plurality of flat tubes lying next to one another in the block depth direction are provided for the tube block.

The tube block according to the invention is particularly well suited, among other things, to evaporators of automotive air conditioning systems working with the refrigerant CO ₂ , in that it is sufficiently pressure-stable and has a comparatively small internal volume, whereby besides the already mentioned further realizations are possible. For example, manifolds without transverse partition walls can be provided, ie all tube units of a block unit are flowed through in parallel. In this case, the manifold connections are arranged alternately on one and the other manifold tube block side. As another variant, you can the collecting duct connections are formed by deflecting pipes which deflect the medium flowing through from pipe units of a block unit into the pipe units of at least one neighboring block unit. For this purpose, these tube units of the block units involved then open into a common deflection space formed in front of the deflection tube, which thus integrally comprises the connected collecting channels of these block units.

Claims (10)

1. The Heat exchanger tubular block containing at least one block unit (1) comprising a plurality of heat exchanger tubular units arranged succesively in a direction of the block height, said tube units each having a plurality of flow ducts extending transverse to the block, and associated laterally arranged collector ducts (8a-11b, 12), extending in said block height direction, where said collector ducts (8a-11b, 12) contain slot openings formed in a direction vertical or tilted to the block depth and where each slot opening engages the associated twisted tube ends (3a, 3b) from the straight flat tubular bundles (2) that form the heat exchanger tubular units, and where said block units (1) are arranged successively, and wherein at least one collector-duct connection (13a, 13b, 13c) is provided between at least two adjacent block units (1). Said collector-duct connection (8a bis 11 b, 12) directly connects a collector duct (8a bis 11 b, 12) of one block unit (1) to a collector duct of the other block unit (1) where further slot openings are formed in the collector ducts (8a bis 11 b, 12) to provide collector-duct connections (13a, 13b, 13c) and where at least a portion of the flow ducts that run in the direction transversal to the block depth are formed by a multi-chamber flat tube (2c) extending over at least one block unit (1) in the direction of the block depth. Said multi-chamber flat tube (2c) is subdivided at each of opposite ends by at least one longitudinal slot (36₁, 36₂, 36₃) into at least two separate end segments (37₁ to 37₄) each twisted about their own longitudinal centerline.
2. The Heat exchanger tubular block according to claim 1, including at least one collector-duct connection (13a, 13b, 13c) to be provided between every pair of adjacent block units (1) forming a fluidal flow path serially connecting the block units (1).
3. The Heat exchanger tubular block according to claim 1 or 2, wherein a collection chamber consisting of several parts is to be located laterally to at least one side of the block unit (1) and where said collection chamber contains a plurality of collector ducts (8a to 11b) separated from one another by a transverse partition (7a to 7d).
4. The Heat exchanger tubular block according to one of the claims 1 to 3, wherein the collector duct or the collector ducts (8a to 11b, 12) of each block unit is formed by seperate collector tubes (4a to 4d, 5a) adjacent ones of said collector tubes being spaced apart by at least one distance element (16a, 16b, 16c) shaped or attached accordingly.
5. The heat exchanger block according to claim 4, wherein said distance element (16a, 16b, 16c) is one of a shaped sheet-metal piece (20) or a tubular piece (17) having at least one slot opening formed therein providing said one collector-duct connection (13a, 13b, 13c).
6. The heat exchanger block according to claim 4 or 5 wherein said distance element (16a, 16b, 16c) includes at least one outwardly bulged through-opening (28, 29, 34, 35) provided by at least one of the two said connected collector tubes (26, 27, 32, 33) forming part of said one collector-duct connection (13a, 13b, 13c) between said collector ducts.
7. The heat exchanger block according to claim 4 to 6, wherein said distance element (16a, 16b, 16c) includes a pair of fluid-tight, mutually engaging through-openings (28, 29, 34, 35) of which at least one is outwardly bulged.
8. The heat exchanger block according to claim 1 to 7, wherein a part of the slot openings formed in a vertical or tilted direction to the block depth and contained in said collector ducts (8a bis 11 b, 12), provide laterally placed inlet- (14) and/or outlet-openings (15) for a temperature control medim.
9. The heat exchanger block according to claim 1 to 8 including a heat-conducting corrugated rib (6) positioned between each adjacent pair of said heat exchanger tube units, whrere a single said corrugated rib (6) or a plurality therof, adjacently placed and of identical or different width and of identical or different rib density, is to extend over the entire block depth in the direction of said block depth.
10. Multi-chamber flat tube according to one of the claims 1 to 9, characterized through one or several longitudinal slots (36₁, 36₂, 36₃) which form a majority of separate end segments (37₁ to 37₄) each twisted about their own longitudinal centerline.