DE3126838C1 - Coolant evaporator, in particular for air-conditioning installations in motor vehicles - Google Patents

Abstract

An evaporator for motor-vehicle air-conditioning installations comprises essentially an evaporator block of ribbed-pipe construction and a junction box (7), in which in each case beginning and end of the parallel-connected evaporator pipes (5) are fastened. The ends of the evaporator pipes (5) open into a common collecting space (13). Arranged in the junction box (7) is (according to Figure 1) a Venturi distributor (9) which divides the coolant up into a number of part flows. Designed in the junction box (7) are ducts (11), the number of which corresponds to the number of the part flows and through which the part flows are guided from the Venturi distributor (9) to the evaporator pipes (5). <IMAGE>

Description

The invention relates to a refrigerant evaporator, in particular for air conditioning systems in motor vehicles

witness, the genus specified in the preamble of claim 1.

From DE-OS 28 47 525 a refrigerant evaporator for air conditioning systems is known, which consists of a Evaporator block, which comprises a plurality of pipe forks and air guide fins, and a connection box consists. A distribution area and a collecting area are integrated in the connection box. Via a refrigerant injection nozzle the refrigerant reaches the distribution room, flows through the U-shaped bent pipe forks and is drawn off via a compressor suction line after it has entered the collecting space.

In such an evaporator, all the evaporator tubes consist of tube forks, each tube fork All pipe forks are connected in parallel Evaporator tubes. With such a structure, there is an even distribution of what is present in two phases Refrigerant with the same phase components in all parallel-connected evaporator tubes is only sufficient possible if the number of parallel evaporator tubes is very small. With the in Motor vehicles of the usual performance range mean that the evaporator is very slim and with a large size Pipe fork lengths must be carried out. The installation space required for this is usually not available Disposal. Because the plurality of evaporator tubes from a common injection and distribution chamber is not evenly distributed due to the uneven distribution of the refrigerant flow Cooling effect achieved over the block volume, which ultimately leads to a reduced performance of the evaporator leads.

From US-PS 28 03 116 a derived from the Venturi nozzle refrigerant flow distributor is known This distributor consists of a Venturi nozzle on its inlet side and one on the outlet side Large number of outlet channels, the individual diameters of which are smaller than the narrowest cross section of the Venturi nozzle. The outlet channels are arranged symmetrically on a conical surface. They form the center of the Venturi nozzle has a conical tip. In known evaporators are in the outlet channels of the Venturi distributor Soldered distribution pipes that are connected to the evaporator pipes, with the number the outlet channels the number of evaporator tubes, which consist of several tube forks connected in series exist, corresponds to In order to achieve the same flow resistance in all inlet pipes, they must individually bent and straightened, which causes high costs. Also soldering the pipe forks and the functional tests that are necessary for this are costly operations.

It is therefore the object of the invention to provide a refrigerant evaporator as described in the preamble of the claim 1 to create the genus mentioned, which is simple in structure and inexpensive to manufacture and with which a cooling capacity evenly distributed over the evaporator block is achieved.

This object is achieved according to the invention in a refrigerant evaporator of the type specified by the characterizing features of claim 1 solved

An advantage of the refrigerant evaporator according to the invention is to be seen in the fact that the once evenly split refrigerant flows are maintained over the entire length of the pipe and thus a uniform Evaporation in all tubes is guaranteed, which leads to a good degree of utilization and an optimal one Dimensioning of the evaporator made possible in the first place.

According to a preferred development of the invention, the number of outlet channels corresponds to the number of the parallel evaporator tubes. The outlet channels are via the channels with the individual evaporator tubes tied together. So that the outlet channels of the Venturi distributor are always congruent with the channels and each other cannot twist in relation to this, the ι ο Venturi nozzle is form-fitting and in a housing opening arranged to prevent rotation.

In order to obtain a simple and space-saving arrangement of the connection box, it is from The advantage that the channels between the Venturi distributor and the evaporator tubes are arranged radially and each open into a connecting piece, the collecting space has several connecting pieces and the evaporator tubes are fastened in the connection piece in a refrigerant-tight manner. To have the same pressure drop in all ducts To achieve, it is useful that all channels are of the same length and have the same diameter. Provided For structural reasons, the channels have different lengths and still in all channels of the If the same pressure drop is to be achieved, it is advantageous that the longer channels have a larger one Have diameters than the shorter channels. Depending on the arrangement of the compressor suction line in the The different speed profile in the collecting space eliminates the disturbance influences that occur Collective space compensated by adjusting the diameter of the channels.

The fastening and sealing of the venturi manifold in the junction box can be done in various ways. For a detachable connection, it is suggested that the Venturi distributor is flanged by flanging rags or by means of a banjo screw on the connection box is attached and sealed by means of a sealing ring. A simple, non-detachable attachment of the Venturi distributor in the connection box, in which no sealing ring is required, is that the Venturi distributor is glued into the connection box. For this purpose, the Venturi distributor has on its lateral surface Forming that meets the requirements of adhesive technology. This can be a variety in Be circumferential grooves or knurling. The ones from the grooves or knurling formed cavities take on the adhesive, which is used for fastening and sealing. For one The simplest possible design of the connection box is each of the evaporator tubes only at its beginning and its end fastened in the connection box. For this purpose, each of the evaporator tubes is preferably made of several pipe forks that are connected to one another by pipe bends.

In the features of claim 12 measures are specified through which it is possible to achieve several To connect pipe forks to an evaporator pipe in series, without separate pipe bends for Connection of the pipe forks must be soldered. This configuration of the connection box is a much simpler structure of the evaporator block is achieved Arrangement of deflection ducts in a one-story connection box is hardly possible. It is therefore advantageous that the connection box is formed in two parts and comprises a cover part and a bottom part, the The dividing plane runs between the connecting pieces and the deflection ducts.

31 26

Hch a large connecting surface between the cover part and bottom part. In the features of claims 17 and 18 are measures to increase the rigidity and tightness of the connection between the cover part and Bottom part indicated.

If a multi-part connection box with large connecting surfaces is undesirable, it is It is advantageous that there are openings in the junction box below the ducts and transversely to them are provided, which are used to hold fingers of an insert. On the connecting piece facing side of the fingers are the deflection channels, wherein in the area of each deflection channel two connecting pieces open into the openings. Measures to close the openings by suitable means for fastening and sealing the insert are in the features of claims 14 and 15 specified.

There are many factors to consider when choosing a material. So it must be taken into account whether the material is refrigerant tight, d. H. the refrigerants, especially fluorocarbons, are not affected by the Diffuse material. Also, the workability of the material, the price and weight of Meaning. For these reasons, the junction box is preferably made of fiber-reinforced polyamide or aluminum. To prevent the refrigerant from diffusing through, the connection box be lined and / or sheathed with a coating of refrigerant-proof material.

Embodiments of the refrigerant evaporator according to the invention are shown below with reference to the drawing explained in more detail. In the drawing shows

Fig.l as a distribution and collecting box trained connection box (partly in section) with schematically shown refrigerant evaporator,

F i g. 2 shows a junction box which is partially according to the line I-I and the line II-II in F i g. 1 is cut,

3 shows a connection box with integrated deflection channels (partly in section),

F i g. 4 shows a junction box which is partly according to the line IV-IV and the line V-V in FIG. 3 is cut,

5 shows an insert containing the deflection channels,

F i g. 6 a section through the insert along the line VI-VI in F ig. 5,

F i g. 7 is a side view of the FIG. 1 and 3 connection box shown,

Fig. 8 shows the arrangement and sealing of a venturi manifold in the connection box,

F i g. 9 shows a variant of FIG. 8th,

10 a sealed by the fastening means Venturi manifold,

F i g. 11 shows a section of a two-part Connection box.

In Fig. 1, a refrigerant evaporator 1 is shown schematically, which consists of a plurality of tubes 2, 2 ', Evaporator tubes 5 formed by tube forks 3 and tube bends 4 as well as transversely to tubes 2 or tube forks 3 arranged lamellae 6 consists. The tubes 2 each form the beginning and end of the evaporator tubes 5, which are shown in FIG a distribution and collecting box, hereinafter referred to as connection box 7, are attached.

The connection box 7 has a refrigerant inlet 8, which is on the inlet side of a Venturi distributor 9 The Venturi distributor 9 has several outlet channels 10, one for each evaporator tube 5 Outlet channel 10 is provided. The outlet channels 10 open into channels 11, each of which has one Connection piece 12, each of which receives a tube 2, is in communication with one of the evaporator tubes 5.

So that the outlet channels 10 are always congruent with the channels 11, is used as a rotation lock on the The end face of the Venturi distributor 9 is provided with a recess 26 in the form of a rectangular or elongated hole, into which a adapted projection 27 of the connection box 7 engages, whereby a positive connection

ic is reached. The pipe 2 ', which the other end of the Evaporator tube 5 forms, is fastened in a connection piece 14 and opens into a tubular Collection space 13. The collection space 13 is connected to a compressor suction line 15.

In Fig. 2 der'Anschlusskasten 7 is partially in the Top view and partially shown in section along the lines I-I and II-II. Through the section I-I is right in F i g. 2 the collecting space 13 with the connecting piece 14 and the compressor suction line 15 are visible. Of the Collection space 13 is provided with a closure piece 30, for example in the end of the cylindrical Collection space 13 is glued. The section II-II shows two outlet channels 10, which are assigned in these Channels 11 open. The channels, not shown in section, are denoted by 11 'and the associated connecting pieces are denoted by 12'. From this representation is It can be seen that the channels 11 and 11 'are arranged radially starting from the Venturi distributor 9 are.

In the lower part of FIG. 2 is in dashed lines the arrangement of the pipe forks 3 and pipe brackets 4, which is hidden by the connection box 7, is indicated. The arrangement of all other evaporator tubes is also corresponding; on their representation is

but omitted for the sake of clarity. in the the rest of the reference numerals agree with those of FIG. 1 match. The cut along the line HI-III corresponds to the view in which FIG. 1 is shown.

In Fig. 3 shows a junction box 7 which, in essential parts, corresponds to that of FIG. 1 corresponds to the reference numerals for the same parts agree with those of FIG. 1 match. In contrast to the Arrangement according to FIG. 1 is the junction box 7 in Figure 3 below the channel 11 between the Connection piece 12 and the collecting space 13 formed as a block 16 in which two transversely to the channels 11 extending and parallel to each other arranged openings 17, 17 'are present. In these openings 17,17 'open out several connecting pieces 18,19,20,21, their number and arrangement later on FIG. 4 is explained.

Below the connection box 7, an evaporator block 1 is shown schematically, which consists of pipe forks 31, 32,33 and the lamellae 6 arranged perpendicular thereto. The pipe forks 31 is at one end in Connection piece 12 and the other end in the connection piece 18 attached. The pipe fork 32 leads from the connecting piece 19 to the connecting piece 20, and the pipe fork 33 opens into the connecting piece 21 and 14th

In the openings 17, 17 'there are fingers 22, 22' of an insert 24, the fingers 22, 22 'having deflection channels 23, 23' on their side facing the connecting pieces 18, 19, 20, 21, which are arranged so as to that each deflection channel 23, 23 'connects two connecting pieces 18 and 19 or 20 and 21 and thus also two pipe forks 31 and 32 or 32 and 33. In this way, the pipe forks 31, 32 ₅ 33 together with the

Deflection channels 23, 23 'an evaporator pipe beginning in the connecting piece 12 and ending in the collecting space 13.

In Figure 4, the junction box 7 is partially in the Top view and partially in section along lines IV-IV and V-V in FIG. 3 shown. So much for the parts correspond to those of the previous figures, these are provided with the same reference numerals. in the lower part of FIG. 4 is through the section IV-IV on the right side of the collecting space 13 with the Connection piece 14 and the compressor suction line 15 are visible. Extend parallel to the collecting space 13 the openings 17, 17 ', in which the fingers 22, 22' of an insert 24 are located. The slot 24 has one Base 25, 25 ', which carries the fingers 22, 22' and at the same time for closing the openings 17,17 'and of the collecting space 13 is used.

The measures known for boxes of heating or air conditioning systems can be provided for fastening and also for sealing the slide-in unit 24 be. Fastening takes place - depending on the material of the box - for example by means of screws or rivets or stapling or by crimping, caulking or gluing. The seal can for example by a sealing ring, a sealing plate or an adhesive can be achieved. For gluing the insert 24 with the connection box 7 is a tongue and groove connection of the base 25 and the connection box 7 particularly suitable.

In the fingers 17,17 'the deflection channels 23 and 23' are arranged, each of which is a connection between make the connecting pieces 18 and 19 or 20 and 21. With dashed lines are the pipe forks 31, 32 and 33 are indicated, which together with the deflection channels 23 and 23 'have a connecting piece 12 Form the evaporator tube leading to the collecting box 13. The arrangement of all others is the same Evaporator tubes, each of which leads from a connecting piece 12 'to the collecting box 13.

Section V-V shows two outlet ducts 10 which open into ducts 11 assigned to these. Not in the Channels shown in section are denoted by 11 'and the associated connecting pieces are denoted by 12'. Just as in FIG. 2, it can also be seen from FIG. 4 that the channels 11, which lead to the outer Connection pieces 12, 12 'lead, are longer than those that lead to the middle connection pieces 12' to lead. In order to achieve the same pressure drop in all channels 11, 11 ', the different Lengths can be compensated for by choosing the appropriate diameter, d. H. the longer channels will be slightly larger in diameter and the shorter ducts a little smaller. In the upper part of FIG. 4 is Shown by dashed lines as fingers 22 and 22 'move up close to the opposite side of the Terminal box 7 extend.

F i g. 5 shows the insert 24, which consists of the base 25, 25 'and the fingers 22 and 22' attached to it. The part 25 'of the base 25 is provided as a closure piece of the collecting space 13 and therefore the The diameter of the cylindrical collecting space 13 is adapted. The upper finger 22 'has six deflection channels 23 'on. Likewise, six deflection channels 23 are provided in the lower finger 22. The arrangement of the Deflection channels 23, 23 'with regard to their length and position always depends on the arrangement of the connecting pieces 18 to 21 to be connected to each other. In Figure 6 is a section through the insert 24 in F i g. 5 indicated after the line VI-VI. The reference numbers of the individual parts agree with those of Fig. 5 match. The finger 22 is in the area of a Deflection channel 23 and the finger 22 'cut in the area between two deflection channels 23'.

F i g. 7 shows a side view of the junction box

7, namely the side on which the inlet and outlet of the refrigerant are arranged. It's on this side a housing opening 28 visible, which is used to receive the

ίο in F i g. 1 to 4 shown Venturi distributor 9 is used.

At the bottom of the housing opening 28 six channels 11 are arranged in a circle so that the nozzle openings 10 of the Venturi distributor 9 open into the channels 11. The projection 27 serves as a rotation lock, the one has an elongated shape.

In Fig. 8 is a first example of the attachment and the sealing of the Venturi distributor 9 in the connection box 7 is shown in the connection box 7 Venturi distributor 9 is installed in opening j28, between a step 29 on the connection box 7 and a step 34 on the body of the Venturi distributor 9 a sealing ring 35 is inserted. The connection box 7 has at the outer end of the opening 28 over the latter Circumferentially arranged tabs 36, which are flanged and thus for fastening the Venturi distributor 9 are used. Otherwise, the reference symbols and arrangements agree with those already previously described figures match.

In Fig.9 is another embodiment of the Fastening of the Venturi distributor 9 in the connection box 7 is shown. In contrast to the arrangement in FIG. 8th the housing opening 28 has a thread 37 in its outer region. A banjo bolt 38 in its Bore accommodating a section of smaller diameter of the Venturi distributor 9 is in the thread 37 rotated and thus presses the venturi 9 against the sealing seat. Otherwise, the reference symbols agree correspond to those in Fig. 8. It is therefore not repeated

Fig. 10 shows a Venturi manifold 9, which at his The outer surface has a plurality of grooves 39 in the circumferential direction Opening 28 and the body of the venturi manifold 9 formed cavities into which adhesive during assembly is introduced. The adhesive is used to fasten and seal the Venturi distributor in the connection box 7. Instead of being provided with grooves 39, the jacket surface of the Venturi distributor 9 can be knurled.

In Fig. 11 is a two-part connection box shown, the one in F i g. 3 and consists of a cover part 40 and a bottom part 41 consists In the cover part 40 are the channels 11, the collecting space 13 and the deflection channels 23, 23 ' The pipe forks 31, 32 are arranged in the bottom part 41, which contains the connecting pieces 12, 14 and 18 to 21 and 33 attached.

The dividing plane of the connection box 7 runs between the deflection channels 23, 23 ′ of the cover part 40 and the connecting piece 12, 14, 18 to 21 of the bottom part 41, whereby to increase the strength and tightness of the connection of the two parts on the bottom part 41 Projections 44 are provided which engage in corresponding depressions in the cover part 40. The protrusions 44 and corresponding depressions can be in the form of a tongue and groove connection (such as in DE-OS 47 525 described).

It is of course possible to make the connection box in several parts or in the case of a two-part

Arrangement to place the separation point on a different level. This means that different requirements can be for example in terms of easy assembly or with regard to suitable manufacturing tools.

For this purpose 4 sheets of drawings

Claims (20)

Patent claims: 1. Refrigerant evaporator, in particular for air conditioning systems in motor vehicles, with an evaporator block in finned tube construction and a connection box, with several parallel evaporator tubes at least with their beginning and end are attached to the junction box and with the ends in open into a common collecting space of the connection box, characterized in that that in the connection box (7) a Venturi distributor (9) is arranged, which has several outlet channels (10) has, which open into the connection box (7) formed channels (11,11 '), the number of which corresponds to the number of Corresponds to partial flows, and that the parallel evaporator tubes (5) to the Venturi distributor (9) remote ends of the channels (11, 11 ') connected are, 2. refrigerant evaporator according to claim 1, characterized in that the number of outlet channels (10) corresponds to the number of evaporator tubes (5). 3. refrigerant evaporator according to claim 1 or 2, characterized in that the outlet channels (10) are arranged evenly distributed on a conical surface of the Venturi distributor (9). 4. refrigerant evaporator according to one of claims 1 to 3, characterized in that the Venturi distributor (9) arranged in a housing opening (28) of the connection box (7) and provided with means (27) is provided against twisting. 5. refrigerant evaporator according to one of the preceding claims, characterized in that the channels (11, 11 ') are arranged radially and each open into a connecting piece (12, 12') and the collecting space (13) has connecting pieces (14) on which the evaporator tubes (5) are refrigerant-tight are attached. 6. refrigerant evaporator according to claim 1 or 5, characterized in that all channels (11, 11 ') are of the same length and have the same diameter. 7. refrigerant evaporator according to claim 1 or 5, characterized in that the channels (11, 11 ') have different lengths and the longer channels (11) have a larger diameter than the shorter channels (H '). 8. refrigerant evaporator according to one of claims 1, 5 or 7, characterized in that by the arrangement of a compressor suction line (15) caused interference by adjusting the diameter of the channels (11, 11 ') are compensated. 9. refrigerant evaporator according to claim 4, characterized in that the Venturi distributor (9) by flanging flaps (36) or by means of a banjo screw. (38) on the connection box (7) is attached and sealed by means of a sealing ring (35). 10. refrigerant evaporator according to claim 4, characterized in that the Venturi distributor (9) a plurality of circumferential grooves (39) or one on its outer surface Has knurling and that the Venturi distributor (9) is fixed in the connection box (7) by means of adhesive and is sealed. 11. Refrigerant evaporator according to one of the preceding claims, characterized in that that each of the evaporator tubes (5) consists of several individual tubes and / or tube forks (3), the are connected to one another by pipe bends (4). 12. Refrigerant evaporator according to one of claims 1 to 10, characterized in that im Terminal box (7) between the connecting pieces (12, 12 'and 14) deflection channels (23, 23') are provided are, into which connecting pieces (18, 19, 20, 21) for receiving the pipe forks (31, 32, 33) open, two pipe forks (31 and 32 or 32 and 33) each through one of the deflection channels (23, 23 ') with one another are connected. 13. Refrigerant evaporator according to claim 12, characterized in that in the connection box (7) between the connecting pieces (12, 12 'and 14) openings (17, 17') for receiving fingers (22, 22 ') of an insert (24) are arranged and the fingers (22, 22') on their connecting pieces (18, 19, 20, 21) have the deflection channels (23, 23 ') facing side and in the area of each deflection channel (23, _ 23 ') two connecting pieces (18 and 19 or 20 : and 21) sinxtie openings (17, 17 ') open. 14. Refrigerant evaporator according to claim 13, characterized in that the fingers (22,22 ') receiving openings (17, 17 ') and the collecting space (13) designed as blind holes on the same side of the connection box (7) and arranged through a base (25) of the insert (24) are closed in a refrigerant-tight manner. 15. Refrigerant evaporator according to claim 13 or 14, characterized in that the insert (24) by means of screws, rivets, clamps, flanging, staking or gluing in the connection box 7 attached and sealed by a sealing ring or an adhesive. 16. Refrigerant evaporator according to claim 12, characterized in that the connection box (7) is designed in two parts and comprises a cover part (40) and a bottom part (41), the plane of division between the connecting pieces (18, 19, 20, 21) and the deflection channels (23, 23 '). 17. Refrigerant evaporator according to claim 16, characterized in that the cover part (40) and the base part (41) interlocking projections (44) and depressions at their connecting surfaces exhibit. 18. refrigerant evaporator according to claim 17, characterized in that the projections (44) and depressions are in the form of a tongue and groove connection are executed. 19. Refrigerant evaporator according to one of the preceding claims, characterized in that that the connection box (7) made of a plastic, preferably fiber-reinforced polyamide, or a Metal, preferably aluminum, is made. 20. Refrigerant evaporator according to claim 19, characterized in that the connection box (7) is lined and / or jacketed with a coating of refrigerant-proof material.