DE19649129A1 - Flat tube heat exchanger with shaped flat tube end section - Google Patents

Description

The invention relates to a made up of flat tubes built heat exchangers in which the flat tubes at least one, in a connection space-forming component, e.g. B. a distribution ler and / or a manifold, opening end section vice versa are shaped.

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 out, for example, as condensate and evaporators used in vehicle air conditioning systems. 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 cold is led through the air conditioning. In this case conventional heat exchangers with ge over their entire length the inner diameter is the flat pipe with a straight line 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  Lich, so that to realize it a larger wall thickness is required to remain the same size in the burst pressure resistance should. When using pipes as connection space-forming Components also have the difficulty that grow with the flat tube width and thus the increasing diameter of the end space-forming pipes whose dead volume increases. In each The case is the width of the connection space-forming component to choose these conventional heat exchangers larger than that of the flat tubes.

In the patent EP 0 565 813 B1 there is a heat exchanger described, the preferred from a plurality of tubes wise oval cross-section is built, the end in triangular openings in the bottom plate of a collector box most used and for this purpose on their pipe end cut into a triangular 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.

In the published patent application EP 0 659 500 A1 there is a heat transfer carrier disclosed, which consists of several, spaced one above the other lying, U-shaped bent flat tubes is constructed. The two legs of the U-shaped flat tubes are ge twisted by 90 ° with respect to their connection area, 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 because the other free end is connected to a collecting channel, with the distribution and collection channels on the same heat transfer are arranged on the side and that via the distribution channel conducted heat transfer medium in a U-shape parallel through the individual flat tubes flows to the collecting duct.

The invention is the technical problem of providing development of 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 a high burst pressure security points and compares with a given flat tube width can be manufactured in a shallow depth.

The invention solves this problem by providing it a flat tube heat exchanger with the features of the An Proverb 1. With this heat exchanger, the flat tubes are in its end opening into the connection space-forming component cut to one opposite its subsequent section narrower transverse extension twisted and / or bent. Here their passage cross-section can also be in the formed end keep section essentially constant. The lesser Transverse extent of the twisted and / or bent flat tube end section opposite the subsequent flat tube cut makes it possible to form the connection space-forming component, e.g. B. a manifold, with a depth realize that is just a little smaller than the reduced cross Extension of the flat tube end section needs to be and can be smaller than the depth of the flat tubes or in any case need not be larger than the same. There at both end sections of each flat tube can be invented be shaped according to the invention, while the flat tubes in intermediate section z. B. straight with her against run across the end sections of greater transverse extent can, which then the depth of the flat tubes and thus even also determined the entire heat exchanger. The invent In accordance with the attainable depth of the connection space bil end components for a given flat tube width has the width ren advantage that the same to achieve a given NEN burst pressure security with a relatively small wall thickness and only a relatively small dead volume have. In addition, the flow of heat can be transferred volume for a given heat transfer capacity ver keep equally low, which if necessary a quantity reduction adornment of the flowing heat transfer fluid against allowed over conventional flat tube heat exchangers.  

In a further developed according to claim 2 heat exchanger are the flat tubes in their opening in the connection space End section at an angle between about 10 ° and 90 ° tor diert, the torsion angle on the respective application case can be coordinated. With increasing torsion angle decreases the depth, d. H. Width, to the on insert the flat tube ends of the required area of the connection space-forming component, while at the same time each flat tube end section with a larger axial extension in the Component opens.

In a development of the invention according to claim 3 is before seen, the flat tube end sections U-shaped or V-shaped to shape and in this way their transverse extension compared to the undeformed state.

In an embodiment of this measure, according to claim 4 U-shaped or V-shaped bent flat tube end sections so far bent so that their bent flanks touch each other derlie, so that only a minimal installation depth for the final space-forming component is required.

In a further developed according to claim 5 heat exchanger are the flat tubes around their longitudinal central axis or around one this parallel longitudinal axis twisted. In the latter case The twisted flat tube can be used for eccentric twisting end sections 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 ° less than that Flat tube width without the flat tubes in their co areas must be laterally offset, what would counteract a shallow depth.

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

Fig. 1 is a schematic side view of part of a flat-tube heat exchanger with an oblique angle tordier th Flachrohrendabschnitten,

Fig. 2 is a schematic sectional view taken along the line II-II of Fig. 1,

Fig. 3 is a schematic side view of part of a flat-tube heat exchanger with perpendicular tordier th Flachrohrendabschnitten,

Fig. 4 is a schematic sectional view taken along the line IV-IV of Fig. 3,

Fig. 5 is a schematic end view of a flat tube with a U-shaped bent end portion for a flat tube heat exchanger and

Fig. 6 is a schematic end view of a flat tube with a V-shaped bent end portion for a flat tube heat exchanger.

The heat exchanger shown in FIG. 1 in a partial, schematic side view can be used, for example, as a condenser in a vehicle air conditioning system. In a conventional manner, it includes a tube / fin block, which in the usual way consists of a stack of flat tubes 1 spaced apart from one another and a corrugated fin structure 2 introduced into the spaces between the flat tubes 1 . The tube / fin block is located between two laterally closing side plates 6 , one of which is shown in the cutout view of FIG. 1. The flat tubes 1 are also conventionally provided on their interior with one or more flow channels through which the refrigerant of an air conditioning system can be passed. At the end, the flat tubes 1 open into a connection space formed by a lateral distributing or collecting tube 3 , one of which functions as a distribution channel and the other as a collecting channel. The flow medium passed through an inlet into the distributor pipe is fed from there in parallel into the flat pipes 1 and traverses them to the opposite collecting pipe 3 , which can be, for example, the round pipe shown in FIG. 1. By means of the Heat Transf gers, a further, by way guided by the structure provided with the corrugated fins 2 interstices between the flat tubes 1 in Wärmeübertragungsverbin flow medium with the dung conducted through the flat tubes 1 Strö mung medium are brought.

It is characteristic of the heat exchanger shown that the flat tubes 1 are twisted in their two end sections 1 a relative to their intermediate central section 1 b by an angle α of approximately 60 ° about their longitudinal central axis, as can be seen more clearly in FIG. 2. As further seen in this sectional view, extend the inserted into the respective manifolds pipe 3 the pipe ends 1 c so obliquely as well to the longitudinal axis 4 of the manifolds tube 3 as well as to the flat pipe transverse axis. 5 Characterized the flat tube ends have a 1 c apart from the height, ie length, of the flat tubes 1 by a factor of cos smaller transverse dimension than the heat transfer active, middle flat pipe section 1 b. This means that the flat tubes 1 also require only one construction area with a correspondingly reduced transverse dimension, ie reduced overall depth, of the distributor or collecting tube 3 . Since the distributor or collector pipe 3 only has to have a slightly larger inner diameter compared to it, this results in the advantage that the distributor pipe and the collector pipe 3 can be made with a relatively small outer diameter R, which in particular can be smaller than that Transverse extent Q of the central Flachrohrab section 1 b, 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 and the collecting tube 3 are provided with corresponding oblique elongated holes for a precisely fitting insertion and soldering of the twisted tube ends 1 c.

By the given flat tube width Q compared to conven union heat exchangers of this type, the smaller inside diameter required for the distributor or collecting tube 3 also has the advantages that the same have comparatively low dead volumes and, given a wall, have a high burst pressure resistance, since their burst pressure resistance decreases with increasing inner diameter. Conversely, given the required bursting pressure resistance, the wall thickness of the distributor and collecting pipes 3 can be reduced compared to conventional heat exchangers with flat pipe ends that do not open out.

In FIGS. 3 and 4 is a variant of the heat exchanger of FIGS. 1 and 2.. In this variant, there is between two side plates 11 , one of which is shown in FIG. 3, arranged tube / fin block, in turn, from a stack of spaced-apart flat tubes 10 , but in the spaces between two flat tubes 10 in this case a double corrugated rib structure 12 is introduced, each consisting of two individual corrugated ribs and egg ner separating this separating plate 13 . In this way, a comparatively large flat tube spacing is realized without any significant impairment of the strength properties and the heat transfer properties of the tube / fin block.

It is characteristic of the heat exchanger of FIGS. 3 and 4 that the end sections 10 a of its flat tubes 10 are twisted relative to the intermediate, middle flat tube section 10 b by an angle β of 90 ° about the longitudinal central axis, as can be seen in more detail in FIG. 4. In order to make this possible without transverse offset of the individual flat tubes 10 , the flat tube distance, more precisely the distance between adjacent middle flat tube sections 10 b, is selected to be slightly larger than the width Q of the flat tubes 10 . Due to this right-angled twisting of the flat tube end sections 10 a, the flat tube ends 10 c, which are inserted into the connection space-forming components, which in turn are realized as a collecting tube 14 and a distributor tube, lie in a line along the distributor or collecting tube longitudinal axis 15 , for which purpose the distributor and the collecting tube 14 are provided with longitudinal slots correspondingly successively introduced in a line on the circumference. Alternatively, the distributor pipe and the collector pipe 14 can also be provided with a continuous longitudinal slot, into which the flat pipe ends are successively inserted with touch contact and then soldered tightly with this.

Can be seen with this right-angled twisting of the flat tube end portions 10 a for the manifold and the header pipe 14 tubes with a particularly small depth, ie ge ringem Diameter R use. Accordingly, their dead volumes can be kept to a minimum, and a relatively small wall thickness is sufficient to achieve a sufficient burst of pressure resistance. Again, the outer diameter R of the manifold and manifold 14 can be selected to be smaller than the transverse extension Q of the flat tubes 10 and thus the tube / ribs block, the transverse extent of which thus determines the construction depth of the entire heat exchanger.

It is understood that in addition to the two examples shown with torsion angles of approximately 60 ° or. approx. 90 ° alternatively any other torsion angle between 0 ° and 90 °, preferably between 10 ° and 90 °, for the rotation of the flat tube end sections compared to their subsequent flat tube section can be realized. Furthermore, as an alternative to flat tubes with twisted end sections, those with end sections bent over to a smaller transverse extent can be used, as is shown in two examples in FIGS. 5 and 6.

The flat tube shown in Fig. 5 by a rectilinear central portion 20 shaped U-into a Endab cut 20 a bent so that the flat tube ends 20 b of the manufactured in this example with a plurality of separate flow channels 21 flat tube has a U-shape having. With such shaped flat tubes, in turn, a heat exchanger of the type shown in FIGS . 1 to 4 can be built up, in which the transverse extension of the insertion area required for inserting the flat tube ends into the installation space forming components makes it significantly less than the transverse extension of the flat tubes or tube / fin block built with it.

Fig. 6 shows a flat tube, which is bent from a rectilinear tenbereich 22 in its end portions 22 a V-shaped, so that the flat tube ends 22 b have a V-shape. As can be seen from FIG. 6, the bent flat tube end sections 22 a also have a substantially smaller transverse extent than the intermediate flat tube middle section 22 in this flat tube type. When building a tube / finned block heat exchanger with this flat tube type, the advantages explained in relation to the above examples are again obtained.

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 nem, the flat tube ends receiving 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 re in their area between the twisted and / or surround end sections also have a curved course Zen. Similarly, the partitions of a double used Corrugated rib structure as an alternative to the course shown perpendicular to the longitudinal axis of the connection space-forming component also in egg nem 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 endab then did not cut to a smaller transverse extent forms into an associated connection space-forming component mün the. Twisting or bending the flat tube end sections can be done in such a way that the passage cross-section the flat tubes also in this area essentially con lets stant what before for most applications is moving.

Instead of the longitudinal center twisting shown in FIGS . 1 to 4, the flat tube end sections can also be twisted outside, ie around an axis parallel to their longitudinal central axis. Especially with right-angled Tor dierung then the distributor and the manifold can be arranged late ral offset relative to the intermediate tube / fin block if the flat tubes are arranged in such a way that their eccentrically tor ded end portions all on one side of the longitudinal center plane of the tube / fin block. This can be advantageous for certain installation situations.

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 median 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 the egg NEN row with lateral displacement between the longitudinal slide  zen of the other row. Because due to the side Offset the longitudinal slots of one row axially across the He height of adjacent longitudinal slots of the other row can stretch, the flat tubes can even with right angular twisting at the end with a small distance in the Put the tube / fin block together. Right in the special case angular 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.

Claims (5)

1. Flat tube heat exchanger with

• - Flat tubes ( 1 ) which are formed on at least one end section ( 1 a) opening into a component ( 3 ) forming the final space,
  characterized in that
• - The flat tubes ( 1 ) are twisted and / or bent in their end section ( 1 a) opening into the connection space-forming component ( 3 ) to a transverse extension that is less than that of their adjoining section ( 1 b).

2. Flat tube heat exchanger according to claim 1, further characterized in that the flat tubes ( 1 ) in their in the connection space-forming component ( 3 ) opening section ( 1 a) at an angle (α, β) between about 10 ° and 90th ° are twisted. 3. Flat tube heat exchanger according to claim 1, further characterized in that the flat tubes ( 20 , 22 ) are bent into a U or V shape in their end section opening into the connection space-forming component ( 20 a, 22 a). 4. Flat tube heat exchanger according to claim 3, further there characterized in that the flat tubes in their in the terminal space-forming component opening end section are bent in a U- or V-shape so that the order curved end section flanks touching each other lying there. 5. Flat tube heat exchanger according to claim 1 or 2, white ter characterized in that the flat tubes in their end opening into the connection space-forming component cut centered around its longitudinal central axis or one  this parallel offset longitudinal axis off-center are dated.