EP1293743B1 - Flat tubes heat exchanger core with deformed tube ends - Google Patents

Abstract

The flat tube block heat exchanger has at least one flat tube (1), which is shaped at least at one end section (1a) to open into a connection zone. The shaped end section of the flat tube is separated into a number of end part-sections (4a,4b) by one or more longitudinal dividing lines (3), with a twist towards its neighboring end section (1b), so that the facing flat sides (5a,5b) lie against each other in the connection zone.

Description

The invention relates to a heat exchanger flat tube block with one or more flat tubes, which are each formed on at least one end portion and open with this in a connection space part. Heat exchangers constructed from such a flat tube block may e.g. be used as a condenser / gas cooler or as an evaporator in vehicle air conditioning systems that work with carbon dioxide or other refrigerant.

In heat exchanger flat tube blocks of this type, as disclosed in the published patent application DE 196 49 129 A1, the flat tubes are twisted in their end portion with their entire undivided width by a predetermined angle of eg between 10 ° and 90 ° or U- or V- shaped bent. This type of design of the flat tube ends makes it possible that connection boxes or manifolds can be used as connection space forming components whose transverse dimension or diameter is not greater than the flat tube width and thus the tube block depth, ie the junction boxes or manifolds are not in the depth direction on the tube block construction in front. In addition, junction boxes or manifolds with relatively low internal volume and therefore high pressure resistance can be used.

Further applications of heat exchanger flat tube blocks with twisted flat tube ends are described in the published patent application DE 198 33 845 A1, where there is also mentioned the possibility that 90 ° twisted flat tube ends of the block structure can be inserted into a common longitudinal slot of a respective lateral header and the connecting space forming Collecting tubes can be divided by transverse partitions into a plurality of collecting ducts in order to achieve a meandering flow guide through the tube block.

With increasing torsion angle decreases in these conventional tube blocks, the transverse dimension of the slots to be introduced into the collecting tube, but at the same time increases the minimum possible flat tube spacing in the block structure. Thus, in the case of a 90 ° twist, a slit width corresponding to the flat tube thickness in the collector tube transverse direction is sufficient, but the mean distance between the flat tubes in the tube block is, for example. when introducing the twisted flat tube ends in a common manifold longitudinal slot at least as large as the flat tube width.

The invention is based on the technical problem of providing a novel heat exchanger flat tube block of the type mentioned, which is comparatively easy and safe to manufacture, with relatively small volume connecting space-forming components and can be realized if necessary with Flachrohrabständen in block construction, which are smaller than the flat tube width ,

The invention solves this problem by providing a heat exchanger flat tube block with the features of claim 1. In this flat tube block a special deformation of the respective flat tube end portion is provided such that the end portion is divided by one or more longitudinal separation lines in several Teilendabschnitte, each individually twisted with respect to a subsequent flat tube middle section and attached to each other with their mutually facing flat sides against each other in the terminal compartment component. This can be done by 90 °, but also at any other angle.

Due to the longitudinal pitch, the width of the Teilendabschnitte is only a corresponding fraction of the flat tube width. Therefore, a slot length which is equal to the corresponding fraction of the flat tube width is sufficient for receiving this deformed flat tube end section in the terminal compartment component. At the same time, although an increased by the factor factor slot width is required, but this is completely unproblematic in most applications, since the flat tube width and thus the tube block depth is usually many times greater than the flat tube thickness, so that nonetheless not on the tube block depth projecting Terminal compartment component is usable.

The reduced insertion slot length required in particular has the advantage that, on the one hand, the dividing end sections of the flat tubes can be twisted by 90 ° as required, whereby the transverse dimension, i. On the other hand, a mean flat tube spacing can be realized in the tube block, which can be significantly smaller than the flat tube width.

In one embodiment of the invention according to claim 2, a division of the flat tube end portion is provided in two Teilendabschnitte specifically, which are twisted in the same direction or in opposite directions and are end-to-end.

In a further development of the invention according to claim 3, a multi-channel flat tube type is used, wherein the respective longitudinal separation line is formed by sawing or scoring the flat tube either between two adjacent flat-tube channels or along a channel. The cut-open channel can be closed if necessary, e.g. by introducing solder in a soldering process during the manufacture of the tube block assembly.

Fig. 1

eine Draufsicht auf einen Endabschnitt eines zum Aufbau eines Wärmeübertrager-Flachrohrblocks verwendeten Flachrohrs nach Einbringen eines Sägeschnitts zur Aufteilung in zwei Teilendabschnitte,

Fig. 2

eine Stirnansicht des Flachrohr-Endabschnitts von Fig. 1,

Fig. 3

eine Draufsicht entsprechend Fig. 1 im fertigen Zustand des Flachrohr-Endabschnitts mit gegensinnig tordierten und gegeneinander angelegten Teilendabschnitten,

Fig. 4

eine Stirnansicht des Endabschnitts von Fig. 3,

Fig. 5

eine Ansicht entsprechend Fig. 3, jedoch für eine Variante mit gleichsinnig tordierten Teilendabschnitten,

Fig. 6

eine Stirnansicht des Endabschnitts von Fig. 5,

Fig. 7

eine ausschnittweise Draufsicht auf einen Flachrohr-/Rippenblock mit Flachrohren gemäß Fig. 1 bis 4 oder gemäß Fig. 5 und 6 für einen z.B. als Gaskühler in einer CO₂-Klimaanlage eines Fahrzeugs verwendbaren Wärmeübertrager,

Fig. 8

eine Ansicht entsprechend Fig. 7, jedoch mit längsgeschnittenem seitlichem Sammelrohr,

Fig. 9

eine Draufsicht auf eine im Sammelrohr der Fig. 7 und 8 verwendete Quertrennwand und

Fig. 10

eine Stirnansicht eines Flachrohr-Endabschnitts entsprechend Fig. 2, jedoch für eine Variante mit ungerader Kanalzahl.

Advantageous embodiments of the invention are illustrated in the drawings and will be described below. Hereby show:

Fig. 1

a plan view of an end portion of a flat tube used for building a heat exchanger flat tube block after introduction of a saw cut for dividing into two Teilendabschnitte,

Fig. 2

an end view of the flat tube end portion of Fig. 1,

Fig. 3

1 in the finished state of the flat tube end section with oppositely twisted and mutually applied Teilendabschnitten,

Fig. 4

an end view of the end portion of Fig. 3,

Fig. 5

a view corresponding to FIG. 3, but for a variant with the same direction twisted Teilendabschnitten,

Fig. 6

an end view of the end portion of Fig. 5,

Fig. 7

1 is a sectional plan view of a flat tube / ribbed block with flat tubes according to FIGS. 1 to 4 or according to FIGS. 5 and 6 for a heat exchanger which can be used, for example, as a gas cooler in a CO ₂ air conditioning system of a vehicle;

Fig. 8

7 is a view corresponding to FIG. 7, but with a longitudinal collector tube cut to the side,

Fig. 9

a plan view of a used in the collection tube of Fig. 7 and 8 transverse partition and

Fig. 10

an end view of a flat tube end portion corresponding to FIG. 2, but for a variant with odd number of channels.

FIGS. 1 to 4 illustrate the manufacturing process for a first flat-tube variant. For this purpose, a pressure-stable extruded flat tube blank 1 of multi-channel type with an even number of e.g. eight individual channels 2 used. In these, centrally at both ends, e.g. about 15mm to 30mm long saw cut 3 introduced in the longitudinal direction, which extends between two adjacent individual channels and divides the respective end portion 1a in two Teilendabschnitte 4a, 4b. The flat tube width B thus corresponds to twice the width T of the two dividend end sections 4a, 4b plus the saw cut width S.

Subsequently, the two Teilendabschnitte 4a, 4b respectively about an axis parallel to the flat longitudinal axis 5 torsion axis, for example, about their own longitudinal central axis, twisted by 90 ° in opposite directions, ie twisted, and then applied with their end with their facing flat sides 5a, 5b against each other , eg by compressing the two twisted ends. Thus, the two mutually abutting flat sides 5a, 5b of the Teilendabschnitte 4a, 4b of a flat side of the end portion 1a in the unformed correspond State of Fig. 1 and 2, while the opposite flat sides 6a, 6b of the two Teilendabschnitte 4a, 4b of the other flat side of the not yet formed end portion 1a correspond.

3 and 4 show the finished flat tube in its one transformed end portion 1a with the two opposite a subsequent flat tube center section 1b twisted and ends with their flat sides against each abutting Teilendabschnitten 4a, 4b. As can be seen in particular from FIG. 4, the overall height of the flat tube ends formed in this way is equal to the width T of the respective dividend end section 4a, 4b and thus only about half the size of the flat tube width B, which determines the tube block depth. By opposing twisting of the two Teilendabschnitte 4a, 4b are located at the mouth end of the flat tube on one side, the former outer narrow sides 7a, 7b and on the other side of the previously adjacent to the saw cut 3 Teilendabschnitt narrow sides 8a, 8b.

5 and 6 illustrate a second flat tube variant, which corresponds to that of FIGS. 1 to 4 with the exception that the two Teilendabschnitte 4a, 4b not in opposite directions, but in the same direction by 90 ° to each have their own, parallel to the flat tube longitudinal central axis 5 Torsionsachse twisted and then put together with the then facing each other flat sides end. In this case, therefore, the two contiguous Teilendabschnitt flat sides 5b, 6a of each one of the two flat sides of the end portion 1a come before forming. In other words, in this embodiment, the two Teilendabschnitte 4a, 4b both in a clockwise direction or both twisted in the counterclockwise direction, while in the embodiment of Figs. 1 to 4 is twisted one clockwise and the other in the counterclockwise direction. Also in the embodiment of FIGS. 5 and 6, the height T of the finished deformed flat tube end corresponds to the width T of each of the two Teilendabschnitte 4a, 4b and is thus only about half as large as the flat tube width B.

7 and 8 illustrate in sections the construction of a tube / rib block of straight, end twisted flat tubes 1 of the type shown in FIGS. 1 to 6 and intermediate corrugated fins 11. Such a tube / rib block is for example for a gas cooler usable with the refrigerant CO ₂ working vehicle air conditioning. The flat tubes 10 are on both sides with their specially shaped end portions 1a, each consisting of the two formed by central longitudinal slot, twisted and abutted Teilendabschnitten inserted in a continuous longitudinal slot 12 each of a laterally arranged on the block manifold 13 fluid-tight.

In order to be able to receive the abutting partial end sections of the inserted flat tube end section 1a, the width of the tube insertion slot 12, which may be e.g. extends continuously along the tubular jacket of the collection tube 13, selected to be slightly larger than twice the flat tube thickness or height, e.g. around 0.1mm or slightly more. The collecting tube 13 is preferably made of solder-plated material. Partitions 14 are introduced into the collecting tube 13, one of which can be seen in FIG. 8 and divide the collecting tube interior into a plurality of collecting chambers 15a, 15b, so that the refrigerant, which is supplied or removed via the collecting tube 13, meanders is passed through the tube block construction.

Fig. 9 shows the partition wall 14 in a plan view. As can be seen, the respective transverse partition wall 14 has a circular shape corresponding to the manifold cross-section, in which a recess 16 is introduced, the width of the width of the manifold slot 12 and the depth of the Flat tube insertion depth corresponds. As a result, the relevant flat-tube end section engages in this recess 16 in a fluid-tight manner.

In this example, since the flat tubes 1 with their divided and twisted end portions 1a are inserted side by side into the through-manifold longitudinal slot 12, the so-called division, i. the distance of the flat tubes 1 in the tube / rib block, the width T of the twisted flat tube Teilendabschnitte and is thus only about half the size of the flat tube width B and thus the depth of the tube / rib block. Since the flat tubes open at the ends by 90 ° twisted into the manifold 13, its diameter can be chosen without difficulty so that the manifold 13 in the block depth direction does not project beyond the tube / rib block, i. the header pipe diameter is equal to or smaller than the flat pipe width B. Here, the block on the other, not shown in FIGS. 7 and 8, opposite flat pipe connection side provided in the same way with a manifold into which the flat tubes 1 divided and twisted in the same way are inserted.

The production of the tube / rib block is done in a conventional manner by mating and soldering of the individual components. Preferably, the flat tubes 1 are provided with a mixture of solder and Nokolok flux prior to twisting their Teilendabschnitte. As a result, in combination with the choice of a solder-plated material for the manifolds 13, a sufficiently gastight connection of the flat tube ends to the respective manifold can be achieved. Alternatively, if non-pretreated flat tubes are used, the achievement of a fluid-tight solder connection can be assisted by applying a solder-flux mixture drop-shaped on each tube side. The fact that the respective two flat tube Teilendabschnitte after being twisted and end-to-end with their flat sides abutting one another, has the effect of a cup or shell shape form, which contributes to a safe whereabouts of the solder material in the necessary place. Also, a supply of solder foil during folding, ie twisting and against each other, the Teilendabschnitte is possible.

Fig. 10 shows in a front view corresponding to Fig. 2 a variant of the flat tube 1 with an odd number of e.g. nine individual channels 2. In the example of FIG. 10, as indicated by dashed lines, the saw cut 3 for dividing the Flachrohrendabschnitts introduced into the two Teilendabschnitte along the central single channel. This therefore remains fluidically passive, i. the refrigerant is only passed through the remaining individual channels. If required, the sawn-in, central single channel can be closed at the end, e.g. be closed by soldering material.

The embodiments described above make it clear that the invention enables a cost-effective and production-safe design of a heat exchanger flat tube block with low weight and uniform temperature distribution. In alternative embodiments or invention, instead of the continuous longitudinal slot, individual, spaced-apart insertion slots may be provided in the collecting tube jacket. For example, the respective manifold is provided with a series of spaced longitudinal slots when the split flat tube ends are twisted by 90 ° and the distance between the flat tubes in the tube block is greater than the width of the Teilendabschnitte and thus greater than the height of the inserted into the manifold Flachrohrendabschnitte. In further alternative embodiments of the invention, the respective two Teilendabschnitte are twisted by an angle less than 90 ° and juxtaposed with their facing flat sides, are introduced for the corresponding in the respective manifold jacket obliquely extending insertion slots.

In a further variant of the invention, the respective flat tube end section is divided by introducing a plurality of longitudinal dividing lines into more than two Teilendabschnitte, which are then twisted and placed end to end with their flat sides. This allows a further significant reduction in the required per flat tube insertion slot length at the manifold and thus the flat tube minimum distance in the tube block.

As an alternative to the sawing described, the dividing of the flat tube end section into the dividing end sections can take place by introducing a respective predetermined tear line, along which the flat tube end section is then separated during the subsequent twisting of the dividend end sections.

Claims (3)

1. A flat tube heat exchanger core having

   - at least one flat tube (1) which is deformed at at least one end section (1a) with which it runs into a connecting three-dimensional part (13),
   characterised in that

   - the deformed flat tube end section (1a) is divided by one or more longitudinal dividing lines (3) into several partial end sections (4a, 4b) which are twisted in relation to a connected flat tube central section (1b) and the facing flat faces (5a, 5b) of its ends are inserted adjacent to one another into the connecting three-dimensional part (13).
2. A flat tube heat exchanger core in accordance with claim 1, further characterised in that
   the flat tube end section (1a) is divided into two partial end sections (4a, 4b) which are twisted in the same direction or in opposite directions with their facing flat faces (5a, 5b) being positioned adjacent to one another.
3. A flat tube heat exchanger core in accordance with claim 2, further characterised in that
   the flat tube is a multi-channel flat tube (1) and the longitudinal dividing line takes the form of a saw or scribe line (3) which runs between two neighbouring channels or along one channel of the multiple channel flat tube.

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