DE3327335A1 - Heat exchanger and method for producing it - Google Patents

Abstract

Heat exchanger, especially for heating and cooling the engines of motor vehicles having liquid-cooled internal combustion engines, consisting of profiled tubes and fins, arranged at right angles to the direction in which the tubes extend, for enlarging the heat-exchanging surface. In such heat exchangers, the tubes are generally joined by soldering to the fins and the floor sheets of the water boxes, since mechanical widening is not possible. The invention relates to a heat exchanger made from thin-walled profiles resembling flat tubes, in which there is no need for soldering and in which, again, mechanical widening is avoided. In accordance with the invention, this is achieved when a.) each thin-walled profiled tube consists in cross-section of at least two identical sections, b.) the widening comes about owing to the fact that the tube cross-section is widened by pushing in a sheet metal strip of the required thickness at right angles to the direction in which the longer cross-sectional axis extends until the tube outer wall bears against the fin collar and c.) the liquid-tight joint between the profiled tubes and the plastic lower part of the water box is a bonded joint in accordance with patent application P 3239950.2. <IMAGE>

Description

THERMAL works

Heating, cooling and air conditioning GmbH
Ebertstrasse 2-4

6909 Walldorf

Heat exchanger and process for its manufacture

The application relates to heat exchangers, in particular for heating and engine cooling of motor vehicles with a liquid-cooled internal combustion engine made of profile tubes and fins arranged at right angles to the direction of extension of the tubes to enlarge the heat-transferring surface.

In the case of heat exchangers of the type mentioned here, the pipes are usually connected to the fins and the base plates of the water tanks by soldering, since mechanical expansion is not possible. In the case of oval tubes that are not too flat, mechanical expansion by permanent deformation of the tube is still possible if the wall thickness is sufficient. In the case of thin-walled and flat profile tubes whose profile geometry as a whole approaches that of a flat tube, such a mechanical expansion is no longer possible. The invention relates to a heat exchanger made of thin-walled, flat-tube-like profiles, in which no soldering is required and in which mechanical expansion by means of an expensive expansion press is also avoided. According to the invention this is achieved in that

a.) each thin-walled profile tube in cross-section made up of at least two there are similar sections.

Patent application heat exchanger .and. 3 / e.r3: aRreu to its manufacture - page jf

b.) the expansion takes place in that the pipe cross-section is pushed in a sheet metal strip of the required thickness transversely to the direction of extension of the longer cross-sectional axis up to the plant of Tube outer wall is extended to the lamellar collar. '

c.) the liquid-tight connection between the profile tubes and the Water tank lower part made of plastic is an adhesive connection according to patent application P 32 39950.2.

The pipes may be made of round or oval sections m air flow direction are arranged one behind the other in the heat exchanger.

The pipe cross-sections required for the invention can be made of thin-walled, seamless or longitudinally welded round tubes, but they can also consist of two rolled half-shells, the connecting edges of which by means of a suitable welding process, for example by means of a burn-off or are also connected in a liquid-tight manner by means of laser welding. Those consisting of a plastic lower part and a plastic upper part Water tanks are after the pipe ends of the heat exchanger package on both sides with the water tank lower parts by an adhesive connection are connected according to the patent application P 32.39950.2, by means of an adhesive process or by friction welding or mirror welding to one another tied together.

In heat exchangers according to the invention, if they are in multiple rows Execution are present, the tubes of the individual rows are one behind the other or they can be arranged offset in a manner known per se. at an offset pipe arrangement, however, in order to save installation depth, it is advisable to place the tubes of the back row, which are arranged in the gap between the front tubes, so that each part of a rear pipe still lies between a part of the front pipe.

The lamellar spacing is fixed by the narrowing in the lamellar opening for the pipes between the individual sections of the pipe cross

Patent application heat exchanger and process for its manufacture - page

cut twice.

The sheet metal strips, which are pushed into the pipes to enlarge the cross section have a wedge-shaped design at their insertion end to facilitate insertion. The sheet metal strips each have in the area of the pipe expansions, openings which are bent alternately to one and the other side. As a result, these metal strips serve at the same time as so-called turbulators to swirl the liquid flow inside the free pipe cross-section. This is appropriate to increase performance, because the liquids flowing in the pipes are water-glycol mixtures, which have a relatively high viscosity.

The following schematic representations are exemplary embodiments of a Shown heat exchanger according to the invention.

It shows:

Figure 1: A heat exchanger for car heating and one for this purpose thin-walled tube according to the invention, which consists of two oval elements.

FIG. 2: A lamellar opening suitable for the tube according to FIG. 1.

FIG. 3: The sheet metal required for the tube according to FIG. 1 for insertion and expanding the pipe cross-section.

FIG. 4: The tube according to FIG. 1 pushed into the lamellar opening before and after inserting the expander strip.

FIG. 5: A lamella with tubes arranged offset according to FIG. 1. Figure 6: A pipe according to the invention which consists of three circular

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Patent application for heat exchanger and process for its manufacture - Page «-

migen elements is constructed and made of two welded together Shells.

FIG. 7: The opening required for a tube according to FIG. 6 in the Slats.

FIG. 8: The expansion sheet metal strip required for a pipe according to FIG. 6.

FIG. 9: The tube according to FIG. 6 inside the lamella opening in front of and after inserting the expansion sheet metal strip.

FIG. 10: A lamella with tubes according to FIG. 6 in an offset tube arrangement.

Figure 11: A lamella with tubes according to Figure 6 in which the tubes one behind the other, so are arranged in line.

The heat exchanger consists of a lamellar pack (.1) made up of tubes is streaked. At both ends of the heat exchanger package there are water tanks made up of a plastic lower part (2) and a plastic upper part (3) exist. There are still Plastic-molded connectors (4) and (5) are available. The the According to the invention, profile tubes (6) extending through the lamella pack (1) and connected to it in a thermally conductive manner can, for example, consist of two oval Sections (7) and (8) exist.

Figure 2 shows the opening (9) required for the aforementioned pipe in the Slats. The opening (9) has a narrow collar (10) on most of the utofang of the opening sections and at the narrow point (37) between the two pipe sections a double angled area (11) through the the lamellae spacing is established. The intermediate plate shown in FIG (13) is inserted into the tube with the tip (14) first by means of an automatic insertion device. Because the intermediate plate (13) is thicker than the distance between the narrow point (12) of the pipe is increased by inserting the intermediate plate, i.e. the pipe becomes perpendicular to

Patent application heat exchanger and process for its manufacture - page $ -

its cross-sectional longitudinal axis expands and lies on the collar (10) of the slat cut-out. This creates the thermally conductive contact between the tube and the lamella as in the case of mechanical expansion. The intermediate sheet (13) has openings (15) in which sheet metal sections (16) are bent out alternately to one or the other side. As a result, these intermediate plates serve. At the same time as turbulators for Swirling of the liquid medium flowing in the pipes. In Figure 4 is shown how a tube in a lamella cut once before Insertion of the intermediate sheet (cf. (17)) and after inserting the intermediate sheet (cf. (18)) is deformed.

FIG. B shows a lamella with staggered oval sections existing pipes, the pipes further forward in the direction of air flow with their rear areas "A" approximately on the same level Height with the front areas "B" of those lying further back in the direction of airflow and tubes located in the gaps between the front tubes. With (19) is the course of the partition wall arranged in the water tank indicated. Another embodiment of a tube according to the invention is obtained if, instead of oval tube sections, those with circular ones Cross-section are provided.

FIG. 6 shows such a tube (20) which extends in the direction of air flow consists of three circular sections (21), (22) and (23) arranged one behind the other and which has two constrictions (24). The pipe is made here as an example of two half-shells (25) and (26) which can be produced for example by rolling from a flat sheet metal strip and which are connected in a liquid-tight manner at the welds (27) by means of a suitable welding process. The opening provided for this pipe in the lamellas (Figure 7) also has a collar (28) and double angled areas (29) in the constrictions (38). When inserting the intermediate plate (30), the tube is pushed apart by the two narrow points (24) and (25) expands and rests on the collar (28) in a thermally conductive manner, while the lamellae spacing is through the tabs (29) is produced. The structure of the intermediate plate (Fig. 8) for this

Patent application - heat exchanger "and VaCfahren TO its manufacture Page <C -

Round areas existing pipes according to the invention is also again so that at the insertion end the intermediate plate is tapered in a wedge shape (3.1) and that in those areas of the pipe which are assigned to the pipe sections are, openings (32) and 'alternately after one or after the other Side bent sheet metal sections (33) and (34) are present in order to cause a swirling of the liquid flowing in the tubes.

FIG. 9 again shows the cross section of an inserted into the lamellae opening Tube, with the left part (35) leveling the tube before it is inserted of the intermediate plate and the right area (36) the deformation of the pipe after inserting the sheet. Even with the tubes which consist of circular sections, the tubes can be as shown in FIG shown offset and arranged in a gap or they can be arranged according to Figure 11 one behind the other, that is, in a line.

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Claims (1)

Claims Heat exchangers, in particular for heating and cooling motor vehicles with liquid-cooled internal combustion engine made of profile tubes and fins arranged at right angles to the direction of extension of the tubes for enlargement the heat-transferring surface, characterized in that that a.) each thin-walled profile tube (6), (25) in cross section of at least two similar sections (7), (8), (2I) -, (22), (23). b.) the expansion takes place in that the Rohrquerstthnitt by pushing a sheet metal strip (13), (30) of the required thickness transversely to the direction of extension of the longer ßuchschnittsacfcse to for the installation of the pipe outer wall on the lamellar collar (10), (28) is. c.) the liquid-tight connection between the profile tubes (6), (25) and the water tank lower part (2) made of plastic series adhesive connection according to patent application P 32 39950.2. Claim 2 Heat exchanger according to claim 1, characterized in that that the profile tubes (6), (25) round (21), (22), (23) or oval (7), (8) There are sections that follow one another in the air flow direction in the heat exchanger are arranged. Claim 3 A heat exchanger according to claims 1 and 2, marked dadurdh ce ichnet in that the profile pipes (6), (25) of seamless dünriwandigen or longitudinally welded round tubes are produced by rolling. Claim 4 Heat exchanger according to Claims 1 and 2, characterized in that the profile tubes (6), (25) consist of two rolled half-shells exist, the connecting edges (27) of which are connected in a liquid-tight manner by means of a suitable welding process. Claim 5 Heat exchanger according to claims 1-4, characterized in that that the water tanks consist of a plastic lower part (2) and a plastic upper part (3), which by means of an adhesive process, connected to one another by friction welding or mirror welding are. Claim 6 Heat exchanger according to claims 1-4, i.e. characterized by that in the case of a multi-row design in the air direction, the pipes of the individual rows are arranged with an offset pipe arrangement so that an area ("B") of a rear pipe still between an area ("A") of the front tubes. Claim 7 Heat exchanger according to claims 1-6, characterized in that the lamellar spacings are fixed in that the Bottlenecks (37), (38) in the lamellar opening for the pipes between the individual Sections of the pipe cross-section are bent twice (11), (29). Claim 8 Heat exchanger according to claims 1-7, characterized in that that the sheet metal strips (13), (30) soft for cross-section expansion be inserted into the tubes, a wedge-shaped one at its fine-pushing end. Have training (14), (31). Claim 9 Heat exchanger according to claim 8, characterized in that the sheet metal strips (13), (30) each in the area of the pipe extensions (7) (8), (21), (22), (23) openings (15), (32) which are bent alternately to one side and to the other side (16), (33), (34).