EP0845647A1 - Flat tube heat exchanger with twisted tube ends - Google Patents

Abstract

The heat exchanger includes flat tubes (1) which have one end sector (1a) deformed to fit in a component (3) forming a connection cavity. This end sector is twisted and/or bent to form an adjacent section (1b) of smaller measurement across the cross section. The flat tubes may be twisted about an angle ( alpha , beta ) between about 10 and 20 degrees at the end fitting in the connection component. This end may be bent in a V shape or a U shape so that the flanks of the bent end sectors are in contact with each other.

Description

The invention relates to a constructed from flat tubes Heat exchanger in which the flute tubes at least one, in a connection space-forming component, e.g. a manifold and / or a manifold, reshaped end portion are.

Heat exchangers constructed from flat tubes, in which the Flat tubes with an unformed end section parallel in one Connection space-forming component, such as a collector and / or a Distribution pipe, open, are used, for example, as capacitors and evaporators used in vehicle air conditioners. Under the term flat tube heat exchanger should be present heat exchangers in disc design are also understood, where rectangular, elongated, hollow discs as "Flat tubes" are used, through the inside of which the refrigerant the air conditioner is passed through. With these conventional Heat exchangers with a straight line over their entire length running flat tubes is the inside diameter of the component forming the connection space by the width of the Flat tubes determined. So with a larger flat tube width a larger inner diameter is required for this component, so that to realize it a larger wall thickness is required if the bursting strength is the same should stay. When using pipes as connection space-forming Components also have the difficulty that with increasing flat tube width and thus increasing diameter of the connection space-forming pipes whose dead volume increases. In in any case is the width of the connection space-forming component to choose larger in these conventional heat exchangers than that of the flat tubes.

In the patent EP 0 565 813 B1 there is a heat exchanger described, which preferably consists of a plurality of tubes oval cross section is built, the end in triangular openings in the bottom plate of a collecting tank used and for this purpose at their Robrend section are formed into a triangle shape. After insertion of the triangular tube end sections into the triangular ones Openings in the base plate widen the pipe ends, around the tubes on the respective base plate two on both sides arranged collection boxes.

A heat exchanger is disclosed in EP 0 659 500 A1 disclosed, which consists of several, spaced one above the other, U-shaped bent flat tubes is constructed. The two legs of the U-shaped flat tubes are opposite the connection area twisted by 90 ° so that they both lie in a common transverse plane. One free each The end of the flat tubes is on a distribution channel and that in each case other free ends connected to a collecting channel, with distribution and collection duct on the same heat exchanger side are arranged and that introduced via the distribution channel Heat transfer medium U-shaped parallel through the individual flat tubes flows to the collecting duct.

US Pat. No. 3,416,600 describes a heat exchanger from Serpentine type disclosed, in which a stack of serpentine curved flat tubes is provided in its end portions are twisted by 90 °. With these twisted end sections the flat tubes are inserted in the associated header tubes, for this purpose, with the circumferential side, in the pipe longitudinal direction extending and spaced apart Longitudinal slots are provided. In addition, the flat tubes be twisted by 180 ° in a central area.

The invention is a technical problem of providing a flat tube heat exchanger of the type mentioned Type based on a comparatively low dead volume in Has connection space, given the wall thickness of the connection space forming Component has a high burst pressure safety, for a given flat tube width with comparatively can be built to a shallow depth and in particular if required can be used as a condenser for air conditioning.

The invention solves this problem by providing it a flat tube heat exchanger with the features of the claim 1 or 2. In this heat exchanger, the flat tubes are in its opening into the connection space-forming component End section to one opposite its adjoining section less transverse extension twisted and / or bent. Their passage cross section can also be formed Keep the end section essentially constant. The less transverse extension of the twisted or bent Flat tube end section opposite the subsequent flat tube section makes it possible for the connection space-forming component, e.g. a manifold, with a construction depth to realize that just a little bigger than the diminished one Transverse extension of the flat tube end section needs to be and can therefore be smaller than the depth of the flat tubes or in any case need not be larger than the same. Here can both end portions of each flat tube in the invention Formed way, while the flat tubes in intermediate section e.g. straight forward with hers the end sections of larger transverse extent can then the depth of the flat tubes and thus possibly also determined the entire heat exchanger. The invention achievable low overall depth of the connection space forming Components with a given flat tube width have the other Advantage that the same to achieve a predetermined Produce burst pressure security with a relatively small wall thickness leave and only a relatively small dead volume have. In addition, the flow through the heat exchanger volume for a given heat transfer capacity comparatively keep low, which if necessary a quantity reduction of the heat transfer fluid flowing through conventional flat tube heat exchangers allowed.

To achieve a compact design even in the direction in which the flat tubes are arranged side by side are, the heat exchanger is twisted according to claim 1 specifically either by an angle not equal to 90 °, see above that the flat tube mouths are at an angle to this Direction and therefore less in this direction Claim installation length, or the flat tube end sections are twisted by 90 °, but then closely aligned in a line in a common longitudinal slot of the terminal space-forming Component inserted. The latter measure has the further advantage that the introduction of a continuous Longitudinal slot in the component forming the connection space in terms of production technology is easier to implement than the introduction a corresponding number of individual slots. Furthermore can the torsion angle to the respective application be coordinated. Decreased with increasing torsion angle the depth, i.e. Width for inserting the flat tube ends required area of the connection space-forming component, while at the same time each flat tube end section a larger axial extent opens into the component.

In the flat tube heat exchanger according to claim 2 are special one or more partitions in the connection space-forming component provided that divide the connection space into several sub-rooms. This measure can be used by the the flat tubes led refrigerant under deflection in one each lateral connection space-forming component sequentially through successive sections of the flat tube stack to lead. If the flat tube end sections are twisted at an angle it is appropriate to also the respective partition with the corresponding oblique angle in the connection space-forming Arrange component.

In a further developed according to claim 3 heat exchanger are the flat tubes around their longitudinal central axis or around one this parallel longitudinal axis twisted. In the latter case one The twisted flat tube end sections can be eccentrically twisted with alternating lateral displacement in the junction part forming component, so that the distance the flat tubes in the non-twisted center area itself a torsion angle of 90 ° can be chosen less than the flat tube width without the flat tubes in their Center areas must be laterally offset, which would counteract a shallow depth.

In a development of the invention according to claim 4, the flat tube end sections bent into a U or V shape to shape and in this way their transverse extension opposite to reduce the undeformed state.

In an embodiment of this measure, the U or V-shaped bent flat tube end sections bent so far, that the two flanks of each tube are bent touch each other so that only a minimal installation depth is required for the connection space-forming component.

In a further developed according to claim 6 heat exchanger with corrugated fins inserted between the flat tubes provided to choose the width of the corrugated fins larger than that of the flat tubes. The resulting rib overhang increases the efficiency of the heat-transmitting corrugated fins and protects the flat tubes against external damage.

In a further developed according to claim 7 heat exchanger are the flat tubes in a technically advantageous manner manufactured as extruded tubes.

In a further developed according to claim 8 heat exchanger is the respective partition axially from one end in inserted the connection space-forming component and has a suitable, with those protruding into the connection space-forming component Flat tube ends in engagement recess.

Fig. 1

eine schematische Seitenansicht eines Teils eines Flachrohr-Wärmeübertragers mit schrägwinklig tordierten Flachrohrendabschnitten,

Fig. 2

eine schematische Schnittansicht längs der Linie II-II von Fig. 1,

Fig. 3

eine schematische Seitenansicht eines Teils eines Flachrohr-Wärmeübertragers mit rechtwinklig tordierten Flachrohrendabschnitten,

Fig. 4

eine schematische Schnittansicht längs der Linie IV-IV von Fig. 3,

Fig. 5

eine schematische Stirnansicht eines Flachrohres mit U-förmig umgebogenem Endabschnitt für einen Flachrohr-Wärmeübertrager,

Fig. 6

eine schematische Stirnansicht eines Flachrohres mit V-förmig umgebogenem Endabschnitt für einen Flachrohr-Wärmeübertrager,

Fig. 7

eine schematische Seitenansicht eines Flachrohr-Wärmeübertragers mit rechtwinklig tordierten Flachrohrendabschnitten und einem mit einer Trennwand versehenen, geschnitten gezeigten Sammel- bzw. Verteilerrohr,

Fig. 8

eine schematische Schnittansicht längs der Linie VIII-VIII von Fig. 7 und

Fig. 9

eine ausschnittweise Schnittansicht eines für einen der gezeigten Flachrohr-Wärmeübertrager verwendbaren Rohr-/Rippenblocks.

Preferred embodiments are shown in the drawings and are described below. Here show:

Fig. 1

1 shows a schematic side view of part of a flat tube heat exchanger with flat tube end sections twisted at an oblique angle,

Fig. 2

2 shows a schematic sectional view along the line II-II of FIG. 1,

Fig. 3

2 shows a schematic side view of part of a flat tube heat exchanger with twisted flat tube end sections,

Fig. 4

2 shows a schematic sectional view along the line IV-IV of FIG. 3,

Fig. 5

1 shows a schematic end view of a flat tube with a U-shaped bent end section for a flat tube heat exchanger,

Fig. 6

1 shows a schematic end view of a flat tube with a V-shaped bent end section for a flat tube heat exchanger,

Fig. 7

2 shows a schematic side view of a flat tube heat exchanger with flat tube end sections twisted at right angles and a header or distributor tube shown in section and provided with a partition,

Fig. 8

is a schematic sectional view taken along the line VIII-VIII of Fig. 7 and

Fig. 9

a partial sectional view of a usable for one of the flat tube heat exchangers shown tube / fin block.

The in Fig. 1 in a partial, schematic side view heat exchanger shown is for example as Condenser can be used in a vehicle air conditioning system. He includes in a conventional manner a tube / fin block, which in usually from a stack spaced apart Flat tubes 1 and one in the spaces between the Flat tubes 1 introduced corrugated fin structure 2 exists. Of the The tube / fin block is located between two on the side final side plates 6, of which in the cut-out view 1 is shown. The flat tubes 1 are inside in a conventional manner as well one or more flow channels through which the Refrigerant can be passed through an air conditioning system. End open the flat tubes 1 in one of a side Manifold or manifold 3 formed connection space, one of which acts as a distribution channel and the other as a collecting channel acts. That through an inlet in the manifold from there, the flow medium is conducted in parallel into the Flat tubes 1 fed in and crosses them to the opposite Collecting tube 3, which for example that in FIG. 1 circular tube to be recognized. By means of the heat exchanger can be another, through with the corrugated fin structure 2 provided spaces between the flat tubes 1 passed Flow medium in heat transfer connection with the flow medium passed through the flat tubes 1 to be brought.

It is characteristic of the heat exchanger shown that the flat tubes 1 are twisted in their two end sections 1a relative to their intermediate central section 1b by an angle α of approximately 60 ° about their longitudinal central axis, as can be seen more clearly in FIG. 2. As can also be seen from this sectional view, the pipe ends 1c inserted into the respective distributor or collector pipe 3 thus run obliquely both to the longitudinal axis 4 of the distributor or collector pipe 3 and to the flat pipe transverse axis 5. As a result, the flat pipe ends 1c have one apart from the height , ie width, of the flat tubes 1 by the factor cosα less transverse extension than the heat transfer active, central flat tube section 1b. This means that the flat tubes 1 also require only one installation area with a correspondingly reduced transverse dimension, ie reduced installation depth, of the distributor or header tube 3. Since the distributor or collector pipe 3 only has to have a slightly larger inner diameter, this has the advantage that the distributor and the collector pipe 3 can be made with a relatively small outer diameter R, which in particular can be smaller than the transverse extension Q of the middle flat tube section 1b, which thereby determines the overall depth of the heat exchanger, as can be seen from the view in FIG. 2. It goes without saying that the distributor pipe and the collecting pipe 3 are provided with corresponding, oblique elongated holes for precisely fitting insertion and sealing soldering of the twisted pipe ends 1c.

Because of the given flat tube width Q compared to conventional Heat exchangers of this type require less Inner diameter for the distributor or manifold 3 are further achieved the advantages that the same comparatively have small dead volumes and for a given wall thickness have a high burst pressure security, because their Bursting pressure resistance with increasing inner diameter decreases. Conversely, given the required burst pressure safety the wall thickness of the distributor and header pipes 3 compared to conventional heat exchangers with not formed confluent flat tube ends can be reduced.

Optionally one in one or both connecting pipes 3 or several partitions 16 may be provided to cover the whole Connection pipe 3 formed connection space in several, in Direction of the pipe longitudinal axis 4 successive subspaces 17a, 17b to subdivide, as shown in Fig. 2. The Partition 16 is the twisted at a helix angle α Flat tube ends 1c corresponding angle obliquely to the tube longitudinal axis 4 in the space between two adjacent pipe ends 1c arranged. Such a division of the respective Connection space in several sub-spaces 17a, 17b is in particular cheap for condensers to the refrigerant from a subspace, e.g. the subspace 17a, into the flat tubes opening into it feed, in the opposite connection pipe in the to divert flat tubes connected to the other partial space 17b and through the latter into this other subspace 17b to lead. If necessary, using several Partitions this flow deflection in the connecting pipes can be repeated as often as desired. That way the refrigerant meanders through the tube / fin block to lead.

3 and 4 is a variant of the heat exchanger 1 and 2 shown. In this variant, the between two side plates 11, one of which is shown in Fig. 3 is arranged tube / fin block again from one Stack of spaced-apart flat tubes 10, however, in the spaces between two flat tubes 10 in this case, a double corrugated rib structure 12 is introduced is, each of two individual corrugated ribs and one this separating partition plate 13 is made. In this way is a comparatively large flat tube spacing with no essential Impairment of the strength properties and the Heat transfer properties of the tube / fin block realized.

Characteristic for the heat exchanger of FIGS. 3 and 4 is that the end portions 10a of its flat tubes 10 opposite the intermediate, middle flat tube section 10b are twisted at an angle β of 90 ° around the longitudinal central axis, as can be seen in more detail in FIG. 4. To do this without cross offset of the individual flat tubes 10 is the flat tube spacing T, more precisely the distance between neighboring middle ones Flat tube sections 10b, slightly larger than that Width Q of the flat tubes 10 selected. Through this right angle Twisting of the flat tube end sections 10a are in the connection space-forming components, which in turn as a manifold 14 and manifold are realized, inserted flat tube ends 10c in a line along the longitudinal axis of the distributor or manifold 15, which includes the manifold and manifold 14th with correspondingly circumferentially in a line in succession introduced longitudinal slots are provided.

Can be seen with this right-angled twist the flat tube end portions 10a for the manifold and Collecting tube 14 tubes with a particularly shallow depth, i.e. low Use diameter R. Accordingly, keep their dead volumes to a minimum, and a relative one is sufficient low wall thickness to achieve sufficient burst pressure safety. Again, the outer diameter R of the Manifold and manifold 14 smaller than the transverse extent Q of the flat tubes 10 and thus the tube / fin block be selected, the transverse extent of which is the overall depth of the entire heat exchanger determined.

The connection pipe 14 shown and if necessary not shown opposite pipe each have one or several partitions 18, which are perpendicular to the pipe longitudinal axis 15 arranged between two adjacent flat tube ends 10c as illustrated in FIG. 4. By the respective Partition 18 becomes the connection space of the connection pipe in question 14 in several successive in the direction of the longitudinal axis 15 of the tube Subspaces 19a, 19b divided. this is like 1 and 2 described above, for example for capacitors expedient to keep the refrigerant in a meandering shape Flow path with deflection in the respective connection pipe one or more times from a subspace of one Connection pipe through a connected part of the flat tubes 10 in the other connecting pipe and from there via one adjacent set of flat tubes 10 in a next subspace to direct the first-mentioned connecting pipe.

It goes without saying that in addition to the two examples shown with torsion angles of approx. 60 ° or approx. 90 ° alternatively each other torsion angles between 0 ° and 90 °, preferably between 10 ° and 90 °, for twisting the flat tube end sections compared to their subsequent flat tube section is feasible. Furthermore, alternatively to flat tubes with twisted end sections those with a smaller one Transverse extent bent end sections used as shown in two examples in FIGS. 5 and 6 is.

The flat tube shown in Fig. 5 is of a straight line extending middle section 20 to a U-shaped end section 20a bent so that the flat tube ends 20b of the in this example with a plurality of separate flow channels 21 manufactured flat tube have a U-shape. With so shaped Flat tubes can in turn be a heat exchanger in the 1 to 4 shown type are built, in which the transverse extent to insert the flat tube ends into the connection space forming Components noticeably required installation area less than the transverse extension of the flat tubes or tube / fin block built with it.

Fig. 6 shows a flat tube from a straight central region 22 bent in a V-shape in its end sections 22a is so that the flat tube ends 22b have a V-shape. How 6 can be seen in this type of flat tube the bent flat tube end portions 22a an essential less transverse extension than the intermediate flat tube middle section 22. When building a tube / fin block heat exchanger with this type of flat tube again the advantages explained in relation to the examples above.

It goes without saying that instead of the round tubes shown Distribution or collection boxes with any other type Cross section can be used as connection space-forming components are one or more pieces and with curved or flat, the flat tube ends receiving the floor can. The required pipe openings can be milled, punched, laser cut or by hydroforming introduced and realized with or without swaths. The Flat tubes, which are also specially designed for heat exchangers can be in slice construction are, for example, in one piece by extrusion or by welding several Pipe parts or by forming and subsequent welding of a blank can be produced.

In addition to the straight line shown, the flat tubes in their area between the twisted and / or bent End sections also have a curved course. The partition walls of a double corrugated rib structure used can be analogous alternatively perpendicular to the course shown to the longitudinal axis of the connection space-forming component also in one acute angle to be arranged obliquely to the same. Of further understood that the flat tubes as required only twisted at one of its two end sections and / or can be bent and with the other end section then not transformed into a smaller transverse extent open into an associated connection space-forming component. Twisting or bending the flat tube end sections can be done in such a way that the passage cross-section the flat tubes are also essentially constant in this area can hold, which is preferred for most applications is.

Instead of the longitudinal center shown in Figs. 1 to 4 The flat tube end sections can also be twisted off-center, i.e. offset around a parallel to its longitudinal central axis Axis, be twisted. Especially when twisted at right angles can then the manifold and the manifold if necessary opposite the intermediate tube / fin block laterally be arranged offset when the flat tubes in this way are arranged sequentially that their eccentrically twisted End portions all on one side of the median longitudinal plane of the tube / fin block. This can be for certain Installation situations may be advantageous.

In a further alternative, the flat tube ends can be so be arranged so that their end portions alternately on one or the other side of this longitudinal central plane of the Pipe / fin blocks are located. Matching are then in the Manifold or manifold two parallel rows of Introduce longitudinal slots, the longitudinal slots of one Row with lateral offset between the longitudinal slots the other row. Because due to the side Offset the longitudinal slots of one row axially across the Extend the height of adjacent longitudinal slots in the other row can, the flat tubes can be used even at right angles end twisting with a small distance in the Put the tube / fin block together. In the special case, more rectangular Twist is this distance down through the limited half the width of the flat tubes, so that it in particular can be smaller than the flat tube width. Accordingly can choose a low height for the corrugated fins, what whose heat transfer efficiency improves. This is true especially for applications where the width of the Flat tubes are less than that of the corrugated fins.

7 and 8 is a variant of the heat exchanger 3 and 4 shown in abbreviated form. As in the embodiment 3 and 4 is also a tube / fin block from a stack spaced apart Flat tubes 30 are provided, the end portions 30a opposite the middle flat tube section by 90 ° around the longitudinal central axis are twisted. However, is between the flat tubes 30 only a corrugated rib structure made of simple corrugated ribs 31 intended. In this example, the distance between the flat tubes corresponds T1 in the block of flat tube width Q1. This has to Consequence that the flat tube ends 30a twisted at right angles each of the two connection sides of the tube / fin block in one Line touching each other, which are parallel to the Longitudinal axis 32 of two lateral connecting pipes 33, 34 runs. Each of the two connecting pipes 33, 34 has one continuous circumferential slot 35 introduced into its circumference, in which the associated, closely aligned in a line, twisted flat tube ends 30a inserted sealed are.

If the flat tubes 30 e.g. when used for a capacitor The refrigerant flows sequentially in groups should be, it is as in the example of FIGS. 1 and 2 also in this example possible one or more partitions 36 to be provided in one or both connecting pipes 33, 34. The Partitions 36 are perpendicular to the longitudinal axis 32 of the connecting pipe and subdivide the connection space of the relevant connection pipe 33, 34 into several sub-rooms 37a, 37b. That in Fig. 7 Left connecting tube 33 shown in section has a in a refrigerant inlet 38 opening into a first sub-space 37a, so that the refrigerant introduced there, as through the flow arrows indicated in the opening into this subspace 37a Flat tubes fed in, from there into the right connection tube 34 transported, there in a subsequent group of with a next subspace 37b of the left connecting pipe 33 connected flat tubes deflected and through these in said next subspace 37b is directed. This meandering Flow routing is repeated as often as necessary until the refrigerant, e.g. also in the former Connection pipe 33 provided refrigerant outlet 39th is brought out.

The respective partition 36 can be in the transition area between two adjoining, twisted flat tube ends 30a or but, as shown in Fig. 7, within the end region of a Flat tube 30b may be arranged when the flat tubes 30 as Multi-chamber flat tubes are formed. The partition 36 then lies between the walls of two adjacent chambers of the flat tube 30b, at least this flat tube 30b is twisted at the end so that each of its chambers on both End faces in the same direction, i.e. up or down below, curved, so that in a connecting pipe 33rd refrigerant introduced into the upper chambers on the other connection pipe 34 also emerges from the chambers above. As can be seen specifically from FIG. 8, the partition wall 36 a slot 36a that the twisted end portion 30a of the corresponding flat tube 30 receives sealed. The partition 36 is axially from an end of the connecting pipe 33 ago used, by the intervention of Flat tube ends 30a guided in their slot 36a against rotation is sealed before reaching the assembly position is determined, e.g. by sealing soldering.

Fig. 9 shows a section of a longitudinal sectional view a tube / fin block as described for the above Heat exchanger can be used. It is characteristic of this Pipe / fin block that the width W of the corrugated fins 40th is chosen larger than the width Q of the multi-chamber tubes realized flat tubes 41. This results in a rib overhang provided that the efficiency of the corrugated fins 40 in terms their heat transfer capacity increases and the Protects flat tubes 41 against external damage. The Ratio Q / W can be 2/3, for example.

In all the examples described above, the flat tubes advantageously be made as extruded tubes. Here It may also be an advantage to have the pipes in front of your end twisting or bending with a solder and flux plating to provide. This facilitates a sealed one Insert the flat tube ends into the connecting tubes using Sealing soldering.

Claims (8)

Flat tube heat exchanger with Flat tubes (1) which are formed at least on an end section (1a, 30a) opening into a connection space-forming component (3, 33),
characterized in that the flat tubes (1) in their end section (1a, 30a) opening into the connection space-forming component (3, 33) are bent to a smaller transverse extent than their adjoining section (1b) or are twisted by an angle α not equal to 90 ° or by an angle of 90 ° twisted and inserted with these end sections (30a) twisted by 90 ° in a line close together in a common longitudinal slot (35) of the connection space-forming component (33). Flat tube heat exchanger with Flat tubes (1) which are bent or twisted at least at an end section (1a) opening into a connection space-forming component (3) to a transverse extension which is smaller than that of their adjoining section (1b),
characterized in that one or more partition walls (18) are provided in the connection space-forming component (3), which subdivide the connection space into a plurality of subspaces (17a, 17b) into which a respectively associated group of successive flat tubes opens. Flat tube heat exchanger according to claim 1 or 2, further characterized in that the flat tubes in their in the terminal section-forming component opening end section their central longitudinal axis in the middle or parallel to one offset longitudinal axis are twisted off-center. Flat tube heat exchanger according to claim 1 or 2, further characterized in that the flat tubes (20, 22) in their end section opening into the connection space-forming component (20a, 22a) are bent into a U or V shape. Flat tube heat exchanger according to claim 4, further characterized characterized in that the flat tubes in their in the connection space forming Component opening end section in such a way U-shaped or V-shaped are bent so that the bent-over end flanks touch each other. Flat tube heat exchanger according to one of claims 1 to 5, further characterized in that between adjacent Flat tubes (41) corrugated fins (40) are introduced, the Width (R) is greater than the flat tube width (Q). Flat tube heat exchanger according to one of claims 1 to 6, further characterized in that the flat tubes of extruded, preferably before bending or twisting solder and flux-clad pipes are formed. Flat tube heat exchanger according to one of claims 2 to 7, further characterized in that the respective Partition (36) has a recess (36a) and axially from a front end into the connection space-forming component (33) is used, the in the connection space-forming component protruding flat tube ends (30a) into the partition recess (36a) intervene.

Images