EP0845647B1 - Flat tube heat exchanger with twisted tube ends - Google Patents

Description

The invention relates to a constructed from flat tubes Heat exchanger in which the flat tubes at least one, in a connection space-forming component, e.g. a distributor and / or a header pipe, 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 pipe end 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, which are introduced on the circumferential side, in the longitudinal direction of the pipe extending and spaced apart Longitudinal slots are provided. In addition, the flat tubes be twisted by 180 ° in a central area.

The published patent application FR 2 712 966 and the patent specification US 5,099,576 disclose flat tube heat exchangers with one Pipe / rib block, the straight line, on both sides at an angle of preferably about 45 ° or less twisted flat tubes has, each in their own, oblique insertion slots side connection pipes are inserted.

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. With this heat exchanger, the flat tubes are in its end section opening into the connection space-forming component to a smaller one than its subsequent section Cross extension twisted by 90 °. It leaves their passage cross-section also in the formed end section keep essentially constant. The lower transverse extent of the twisted flat tube end section opposite the subsequent flat tube section makes it possible Connection space-forming component, e.g. a manifold, to realize with a construction depth that is little greater than the reduced transverse extent of the flat tube end section needs to be and therefore smaller than the overall depth the flat tubes can be or at least not bigger as the same needs to be. Both end sections can twisted each flat tube in the manner according to the invention be, while the flat tubes in the intermediate section e.g. rectilinear with their larger compared to the end sections Lateral extension can run, which is then the depth the flat tubes and possibly also the entire heat exchanger certainly. The low achievable according to the invention Construction depth of the connection space-forming components for a given Flat tube width has the further advantage that the same to achieve a predetermined burst pressure safety with relative Small wall thickness can be made and only a relative have low dead volume. In addition, the flow of heat transfer volume for a given heat transfer capacity keep what is comparatively low Requires a reduction in the volume of the heat transfer fluid flowing through compared to 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 flat tube end portions are close to each other in a line in a common longitudinal slot of the terminal space-forming component inserted. This 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 of one corresponding number of individual slots.

When further developed according to claim 2 flat tube heat exchanger are specially one or more partitions in the connection space Component provided that the terminal compartment divide into several parts. This measure can do this be used, the refrigerant passed through the flat tubes with deflection in a respective lateral connection space forming Component sequentially through successive sections of the flat tube stack.

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 a further developed according to claim 4 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 5 heat exchanger are the flat tubes in a technically advantageous manner manufactured as extruded tubes.

In a further developed according to claim 6 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 Flachrohr-Wärmeübertragers mit rechtwinklig tordierten Flachrohrendabschnitten und einem mit einer Trennwand versehenen, geschnitten gezeigten Sammel- bzw. Verteilerrohr,

Fig. 2

eine schematische Schnittansicht längs der Linie VIII-VIII von Fig. 1 und

Fig. 3

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

Preferred embodiments are described below with reference to the drawings, in which:

Fig. 1

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 with a partition and shown in section,

Fig. 2

is a schematic sectional view taken along the line VIII-VIII of Fig. 1 and

Fig. 3

a fragmentary sectional view of a usable for the flat tube heat exchanger 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 a tube / fin block, which in the usual way from a Stack of spaced apart flat tubes 30 and one introduced into the spaces between the flat tubes 30 Corrugated rib structure consists of corrugated ribs 31. The flat tubes 30 are in the conventional manner with a inside or several flow channels through which the refrigerant an air conditioning system can be passed through. ends the flat tubes 30 open into one of a side connecting tube 33, 34, i.e. Distributor or manifold formed Connection compartment, one of which is used as a distribution channel and the other acts as a collection channel. By means of the heat exchanger can be a flow medium through which with the Corrugated fin structure 31 provided spaces between the Flat tubes 30 is passed through, in heat transfer connection with one passed through the flat tubes 30 Fluid are brought.

It is characteristic of the heat exchanger shown that the flat tubes 30 in their two end sections 30a opposite their intermediate middle section by an angle are twisted by 90 ° around their longitudinal central axis.

The flat tube distance T1 in the block corresponds to the flat tube width Q minus the flat tube thickness. In other words the flat tube ends 30a twisted at right angles lie on each the two connection sides of the tube / fin block in one Line touching each other, parallel to the longitudinal axis 32 two lateral connecting pipes 33, 34 runs. Each of the two connecting pipes 33, 34 has one on its circumference introduced, continuous longitudinal slot 35, in which the associated, close to each other in a line, twisted flat tube ends 30a are inserted sealed.

If the flat tubes 30 e.g. when used for a capacitor The refrigerant flows sequentially in groups As shown, it is possible to use 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 of the connecting pipe 32 and subdivide the connection space of the person concerned Connection pipe 33, 34 in several sub-rooms 37a, 37b. The 1 shows the left connecting pipe 33 shown in section a refrigerant inlet opening into a first compartment 37a 38 so that the refrigerant introduced there, such as indicated by the flow arrows in the in this subspace 37a discharging flat tubes, from there into the right connecting pipe 34 transported, there in a subsequent Group of with a next subspace 37b of the left Connection pipe 33 connected flat tubes deflected and through this is directed into said next subspace 37b. This meandering flow is as often as necessary repeated until the refrigerant is e.g. Likewise provided in the first-mentioned connection pipe 33 refrigerant outlet 39 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. 1, 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 refrigerants introduced into the upper chambers on the other Connection pipe 34 again from the overhead chambers exit. As can be seen specifically from FIG. 2, the Partition 36 has a slot 36a that the twisted end portion 30a of the corresponding flat tube 30 receives sealed. The partition 36 is axially from one end of the Connection pipe 33 used here, whereby by engaging the flat tube ends 30a secured against rotation in their slot 36a is carried out before reaching the Mounting position is sealed, e.g. by sealing soldering.

Fig. 3 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.

The right-angled twisting of the Flat tube end sections for the manifold and manifold Pipes with a particularly shallow depth, i.e. small diameter Use R. Accordingly, their dead volumes can be keep it to a minimum, and a relatively small one is sufficient Wall thickness to achieve sufficient burst pressure security. The outer diameter R of the distributor and the header pipe is smaller than the transverse extension Q of the flat tubes can be selected.

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, for example, are 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 end sections also have a curved course. Furthermore understands yourself that, depending on your needs, the flat tubes only on one their two end sections can be twisted and with the other end section then not to a lesser transverse extent transformed into an associated terminal space Open component. Twisting 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 3 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. The manifold and manifold can then opposite the intermediate tube / fin block be laterally offset when the flat tubes of this type are arranged sequentially that their eccentric twisted end sections all on one side of the Longitudinal center plane of the tube / fin block. This can be for certain installation situations may be advantageous.

In all the examples mentioned above, the flat tubes advantageously be made as extruded tubes. there 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 Tight soldering.

Claims (6)

1. Flat tube heat exchanger with

   flat tubes (30) which are deformed at least at an end portion (30a) opening into a component (33) forming a connection chamber,

   characterized in that

   the flat tubes (30) are twisted, in their end portion (30a) opening into the component (33) forming the connection chamber, through an angle of 90° about a longitudinal axis relative to the central portion of the flat tube, and are inserted, with these end portions (30a) twisted through 90° aligned closely adjacent one another, in a common longitudinal slot (35) of the component (33) forming the connection chamber.
2. Flat tube heat exchanger according to Claim 1, further characterized in that one or a plurality of partitions (36) are provided in the component (33) forming the connection chamber and divide the connection chamber into a plurality of partial chambers (37a, 37b) into each of which a respective associated group of consecutive flat tubes opens.
3. Flat tube heat exchanger according to Claim 1 or Claim 2, further characterized in that the flat tubes are twisted, in their end portion opening into the component forming the connection chamber, centrally about their longitudinal central axis or eccentrically about a longitudinal axis offset parallel thereto.
4. Flat tube heat exchanger according to any one of Claims 1 to 3, further characterized in that corrugated ribs (40), the width (W) of which is greater than the width (Q) of the flat tubes, are mounted between adjacent flat tubes (41).
5. Flat tube heat exchanger according to any one of Claims 1 to 4, further characterized in that the flat tubes are formed from extruded tubes, preferably coated with solder and flux prior to twisting.
6. Flat tube heat exchanger according to any one of Claims 2 to 5, further characterized in that each partition (36) comprises a recess (36a) and is inserted in the component (33) forming the connection chamber axially from one end, during which the flat-tube ends (30a) which project into the component forming the connection chamber engage in the recess (36a) of the partition.

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