EP0029859B1 - Heat exchanger for an evaporator, especially for air conditioning systems - Google Patents

Description

The invention relates to a heat exchanger for evaporators, in particular for air conditioning systems, with a structure corresponding to the preamble of patent claim 1.

The present invention is based on a heat exchanger, as proposed in DE-B-27 28 827 by the applicant, in which the strength of the connection between the water pipes made of metal and the connection boxes made of plastic was increased such that for the knowledgeable Specialist the application of this design could now also be considered for evaporators with their higher pressure loads.

Furthermore, DE-A-2 735 647 discloses a heat exchanger as known, in which distribution and collection spaces, each with a plurality of insertion and return openings, are arranged in aluminum connection boxes.

In these known evaporators, the large number of bushings of the evaporator tubes in the connection boxes have to be produced by relatively complex rolling-in or expanding operations which, in addition to the expensive mechanical equipment, also have the disadvantage that such connections are relatively susceptible to faults.

Furthermore, according to DE-A-2 300 881, a heat exchanger for evaporators is known, in which a distribution of the liquid coolant or refrigerant, which is as uniform as possible for the good efficiency of an evaporator, over the multiplicity of heat exchanger tubes by a complex multi-part design of the connection box to be solved, in which two heat exchanger tubes are combined via a dome called an inlet tank and several of these domes are combined again via a pipe. The pipeline and the domes are enclosed by an outer connection box, which forms the return space.

In its known evaporators, a costly, multi-part construction of the connection box is required for the favorable distribution of the coolant or refrigerant, the individual sheet metal components of which have to be connected to one another in labor-intensive soldering operations.

Although simpler designs with end boxes made of plastic have become known in the obvious technical field of heat exchangers in the past few years, this design, which has meanwhile been introduced into the mass production of heat exchangers, could not be used for evaporators, since the previously achieved strength of the connection between the water pipes Metal and the connection boxes made of plastic were not sufficient to withstand the operating pressures of up to approx. 40 bar that occur with evaporators, especially for air conditioning systems.

The first-mentioned, earlier application by the applicant, however, disclosed a connection of water pipes made of metal and connection boxes made of plastic, the strength of which was considerably higher than that of the previously common connections, so that this design could also be considered for evaporators.

The object of the invention is to develop such a connection box for a heat exchanger for evaporators, starting from the use of plastic connection boxes known in normal heat exchangers, which meets the special requirements for evaporators, namely the most uniform distribution of the liquid coolant or refrigerant a corresponding constructive design takes into account, is much simpler and cheaper to manufacture and enables an improvement in the efficiency of the evaporator by avoiding undesirable cold losses outside the actual heat exchanger zone.

According to the invention, this object is achieved in that an evaporator of the type specified in the preamble has the features indicated in the characterizing part of patent claim 1.

The fact that the connection box consists of a distributor part and a connection part, which are sealed and firmly connected to one another via a tongue and groove connection by means of a hardenable plastic, simplifies the manufacture of such a connection box and thus reduces its production costs.

Characterized in that several, in each case a plurality of injection openings or a plurality of return openings, parallel and mutually parallel injection and return spaces are formed in the distributor part, which are combined again via two correspondingly connecting collecting spaces, the injection and return paths of the refrigerant on the one hand kept to an aspired smallest size and on the other hand guided in insulating plastic, so that the loss of cold, which is hardly avoidable in known evaporators, is prevented and the effective cooling capacity of the evaporator is increased.

The elimination of any molten metal or soldered connections enables the use of evaporator tubes made of aluminum, as a result of which considerable weight savings can be achieved at approximately the same production costs as are sought in particular for evaporators in motor vehicles and the like.

The formation of the connecting pipes for the injection valve and the compressor suction line in one piece with the connecting part and with molded-on collars enables a further simplification of the production, the assembly by means of split, foldable union nuts still being able to be carried out simply and reliably.

• Fig. 1 eine Ansicht eines Verdampferblockes mit einem noch nicht montierten, teilweise im Schnitt gezeigten Anschlußkasten;
• Fig. 2 ene Ansicht des Anschlußteiles in Richtung des Pfeiles II in Fig. 1;
• Fig. 3 eine Ansicht des Anschlußteiles in Richtung des Pfeiles 111 in Fig. 2;
• Flg. 4 eine Ansicht des Verteilerteiles in Richtung des Pfeiles II in Fig. 1;
• Fig. 5 einen Schnitt entlang der Linie V-V in Fig. 4;
• Fig. 6 einen Schnitt entlang der Linie VI-VI in Fig. 5;
• Fig. 7 eine Ansicht in Richtung des Pfeiles VII in Fig. 4;
• Fig. 8 einen Schnitt entlang der Linie VIII-VIII in Fig. 4;
• Fig. 9 einen Schnitt entlang der Linie IX-IX in Fig. 4.

The invention is explained in more detail using an exemplary embodiment shown in the accompanying drawings. It shows:

• Figure 1 is a view of an evaporator block with a not yet assembled, partially shown in section junction box.
• Fig. 2 ene view of the connector in the direction of arrow II in Fig. 1;
• Fig. 3 is a view of the connecting part in the direction of arrow 111 in Fig. 2;
• Flg. 4 is a view of the distributor part in the direction of arrow II in FIG. 1;
• 5 shows a section along the line VV in Fig. 4.
• Fig. 6 is a section along the line VI-VI in Fig. 5;
• Fig. 7 is a view in the direction of arrow VII in Fig. 4;
• Fig. 8 is a section along the line VIII-VIII in Fig. 4;
• 9 shows a section along the line IX-IX in FIG. 4.

The evaporator block shown in the figures consists of a junction box 1 made of plastic, which is sealed and firmly connected to a tube bundle of evaporator tubes 3 made of metal, which is held together by air-guiding fins 2 made of aluminum, via one of the tube ends, which is hardenable plastic 4.

The connection box 1 here consists of a distributor part 5 and a connection part 6, the structure of which is explained in more detail below in connection with the corresponding figures.

2, the connecting part 6 is shown. It has a connecting pipe 7 for the injection valve 8 and a connecting pipe 9 for the compressor suction line (not shown). Both connecting pipes 7 and 9 are provided at their ends with integrally formed collars 10, by means of which they can be fastened via divided, foldable union nuts 11 with the interposition of a sealing ring 12 in a threaded bore 13 in the injection valve 8 or on the compressor suction line.

As can be seen from FIG. 3, the connection side of the connection part 6 is provided with grooves 14 and 15 which merge into one another and form endless loops, the purpose of which will be explained below.

4, the distributor part 5 is shown. It has a base 16, from which a plurality of pipe sockets 17 protrude, which are surrounded by ring webs 19 which form axially open annular grooves 18.

The pipe socket 17 form a plurality of injection openings labeled E and a plurality of return openings labeled R. In each case one pipe socket of an injection opening E is connected to the inlet end of a U-shaped evaporator pipe 3, the outlet end of which is connected to the adjacent pipe socket of the return opening R indicated in broken lines (FIG. 4).

In each case a plurality of injection openings E or a plurality of return openings R are correspondingly merged via tubular injection and return spaces Eo or Ro located parallel to one another on the connection side of the distributor part 5 via two collecting spaces Es or Rs.

As can be seen from Fig. 7, the collecting spaces Es and Rs are surrounded by interlocking, endless loops forming springs 20 and 21.

As can be seen from a consideration of FIGS. 3 and 7, the course of the grooves 14 and 15 on the connection side of the connection part 6 is in agreement with the course of the springs 20 and 21 on the connection side of the distributor part 5. By introducing a hardenable one Plastic in the grooves 14 and 15, sinking the springs 20 and 21 into the plastic-filled grooves and subsequent curing of the plastic, the distributor part 5 are sealed with the connector 6 of the junction box 1 and firmly connected.

Subsequently, the axially open annular grooves 18 present at the bottom 16 of the distributor part 5 can be filled with a hardenable plastic 4 and then the tube ends of the tube bundle consisting of a plurality of evaporator tubes 3 made of metal by sinking into the annular grooves joined with hardenable plastic and subsequent hardening of the plastic sealed with the junction box 1 and firmly connected.

The formation of the pipe stub projecting at the bottom 16 of the distributor part 5 in connection with the ring grooves 18 receiving the hardenable plastic 4 and the ring webs 19 enclosing them and the pipe collar 17 of the evaporator tubes 3 made of metal which can be pushed onto the pipe stub 17 and countersunk into the ring grooves becomes according to the teaching DE-B-27 28 827 executed to ensure a correspondingly high strength of the connection between the connection box 1 made of plastic and the evaporator tubes 3 made of metal.

From the sections shown in FIGS. 8 and 9 through the distributor part 5 of the connection box 1, the transition of the tubular injection and return spaces Eo and Ro into the corresponding collecting spaces ES and RS can be seen.

The two-part design of the junction box 1 enables simple manufacture the respective individual components, the distributor part 5 and the connection part 6 and the connection of these two components practically in the course of establishing the connection between the connection box 1 and the tube bundle of evaporator tubes 3.

The curable plastic can be introduced into the grooves 14 and 15 of the connection part 6 at about the same time as the plastic is introduced into the annular grooves 18 on the distributor part 5, after which the two parts of the connection box 1 and the evaporator tubes 3 can be brought together with the connection box 1 and the entire evaporator block can be completed in one curing operation.

The depths of the grooves 14 and 15 in connection with the height of the springs 20 and 21 and the flange-like design of the connection sides of the two components of the connection box 1 ensure that the curable plastic cannot run in an undesirable manner until the curing process. The tongue and groove connection of the two components of the junction box 1 ensures a connection of high strength, which fully meet the operating stresses of an evaporator.

Claims (1)

1. A heat exchanger for an evaporator, in particular for air conditioning systems, with a single header (1) of synthetic material subdivided into an entrance chamber and a backflow chamber, the header being in sealed relationship and firmly connected via a thermosetting synthetic material (4) with a pipe assembly of U-shaped metal pipes held together by air- guiding fins, the ends of the pipes being embedded in the synthetic material characterized in that the header (1) consists of a manifold (5) comprising several mutually parallel tubular injection- and return chambers (Eo and Ro), respectively uniting a multitude of injection apertures (E) and a multitude of return apertures (R), and two collection chambers (Es and Rs) correspondingly joining the injection-and return chambers, and of a junction piece (6) which complements the collection chambers (Es and Rs) and forms connecting pipes (7 and 9) for an injection valve (8) and a compressor suction pipe, the manifold (5) and the junction piece (6) being held together in sealed relationship and firmly connected one with the other via grooves (14, 15) and springs (20, 21) by means of a thermosetting synthetic material.

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