WO2005033603A2

WO2005033603A2 - Heat exchanger unit

Info

Publication number: WO2005033603A2
Application number: PCT/EP2004/009942
Authority: WO
Inventors: Peter Klug
Original assignee: Eaton Fluid Power Gmbh
Priority date: 2003-10-01
Filing date: 2004-09-07
Publication date: 2005-04-14
Also published as: DE10346141A1; WO2005033603A3; DE10346141B4

Abstract

The invention relates to a heat exchanger unit, in particular suitable for a motor vehicle air conditioning or for other high pressure applications comprising a heat exchanger body in the form of a shaped hollow body provided with several mutually parallel through channels (15, 16) which are serially arranged in such a way that when the parts of the heat exchanger body are removed, the mouths of the channels (15) are axially offset against the mouths of the through channels (16). Said invention makes it possible to obtain a geometrically simple coupling joint which stimulates flowing by uniting the mouths of the through channels (15) and the mouths of the through channels (16) in another collector.

Description

heat exchanger unit

The invention relates to a heat exchanger unit.

Heat exchanger units are used, for example, in air conditioning systems of motor vehicles in the vicinity of the refrigerant compressor, on the one hand to pre-cool the fluid coming from the compressor, which is heated by the compression, and on the other hand to warm up the heat transfer fluid to be supplied to the compressor. The latter is particularly advantageous in those air conditioning systems that are under particularly high pressure and work with alternative refrigerants, such as C02. The compressors used are relatively sensitive and are damaged if the drawn-in refrigerant carries liquid drops. The one in question The heat exchanger should then be arranged as close as possible to the compressor in order to avoid droplet formation on the way from the heat exchanger to the compressor. The heat exchanger is therefore usually exposed to considerable vibrations, which it must withstand. He is also under high pressure. Automotive refrigeration systems with alternative refrigerants must be designed for burst pressures up to 700 bar. Overall, this is not only a challenge for the design of the heat exchanger but also for its connection technology. In addition, such a heat exchanger should have the highest possible heat transfer capacity with a small size.

Based on this, it is the object of the invention to create a heat exchanger unit which is particularly suitable for use in high-pressure applications.

This object is achieved with the heat exchanger unit according to claim 1:

The heat exchanger unit according to the invention has a heat exchanger body which has two flat sides and is designed as a flat body. Longitudinal, parallel through channels are arranged in at least two, but preferably three rows parallel to each other and connected with connections provided at the ends. In this case, the outer through channels, that is to say the closer to the flat sides, are preferably connected to one connection and the inside channels to another connection. The pass-through channels are thus divided into two groups, namely a group that is connected to one connection and another group that is connected to another connection. One group serves as a suction channel and leads, for example, to a cold medium compressor to the fluid while the other group serves as a pressure channel and the compressed fluid coming from the refrigerant compressor. They therefore form a pressure channel.

The refrigerant flow in the channels is relatively fast. In the pressure channel in particular, supercritical fluid states can be achieved as a result of the prevailing temperatures and pressures, in which the fluid assumes a special aggregate state that cannot be assigned to either the gaseous or the liquid aggregate state. In this case in particular, but also in other high-pressure applications, it has proven to be expedient if the suction channels as a whole have a free flow cross section which is significantly larger than the free flow cross section on the suction side. The number of through channels on the suction side is preferably approximately 1.2 to 2 times as large, preferably approximately 1.5 times as large as the number of channels on the pressure side. In addition, the cross sections of the pressure-side channels are considerably smaller than the cross-sections of the suction-side channels. The through ducts on the suction side are preferably provided with a rectangular or square cross section. They have smooth, non-ribbed walls. The pressure-side passage channels are preferably round (circular, oval or similar), with the circular shape being preferred. The walls are also preferably smooth, i.e. without ribs or other projections. The heat exchanger body preferably has an in

Longitudinal direction does not change, ie constant cross-sectional profile. It is preferably designed as an extruded profile, for example as an aluminum extruded profile. It can be formed in one piece. This gives one simple, inexpensive manufacture. However, it can also be constructed in two pieces, wherein both partial bodies can be constructed from the same or from different materials.

External parts of the body can be removed from a heat exchanger body designed as an aluminum extruded profile in the connection areas, so that a section containing only the inner through channels, e.g. rectangular tongue or other connection extension is formed. This can protrude through a slot-like passage provided in the connection piece and can be sealed therein. In this way, the outer and inner through-channels of the heat exchanger body can be connected to different connections with a particularly simple connection piece. In addition, because of the areal connection between the flanks of the connection extension and the slot wall, it is possible to achieve a tensile connection by gluing or soldering or also by other connection techniques that can withstand the mechanical stresses in the engine compartment of a motor vehicle.

Further details of advantageous embodiments of the invention result from the drawing, the description or from claims. Exemplary embodiments of the invention are illustrated in the drawing. Show it:

FIG. 1 shows the heat exchanger unit and its connection to a compressor in a schematic representation,

FIG. 2 shows the heat exchanger unit according to FIG. 1 in a sketchy perspective view, FIG. 3 shows the heat exchanger unit according to FIG. 2 in a partially cut-out, sectional illustration,

Figure 4 shows the connector of the heat exchanger according to Figures 2 and 3 in a cut perspective view

5 to 7 heat exchanger bodies in different embodiments for the heat exchanger according to FIG. 2, each in a perspective view.

A section of a refrigeration machine 1 is illustrated in FIG. belongs to the air conditioning system of a motor vehicle. An essential component of the refrigerator 1 is its refrigerant compressor 2, which is preceded by a heat exchanger 3. Because of its immediate vicinity to the refrigerant compressor 2, it is also referred to as an “internal heat exchanger”. Its function is merely to heat the refrigerant flowing to the refrigerant compressor 2 on the suction side, using the heat of the refrigerant leaving the refrigerant compressor 2. It is preferably flowed through in countercurrent.

FIG. 2 illustrates the heat exchanger 3 separately, which is essentially formed by a heat exchanger body 6, which is contained at the end in connecting pieces 4, 5. Overall, the heat exchanger 3 is particularly robust and pressure-resistant. In addition, it has a particularly small construction volume. To explain its structure, reference is made to FIGS. 3, 4 and 5. The heat exchanger body 6 shown separately in FIG. 5 and in cross section is here a one-piece body with a rectangular cross section. It is flat both on its two flat sides 7, 8 and on its narrow sides 9, 11. For example, it can be formed by an extruded aluminum profile or another profile produced by the continuous casting or extrusion process. It is preferably made of metal, such as aluminum or an aluminum alloy.

The heat exchanger body 6 is penetrated by through channels 15, 16, 17 arranged in three rows 12, 13, 14. For example, the through channels 15, 17, which are each closest to the flat sides 7, 8, are square or rectangular. They preferably have cross sections that match one another and are other separated by partitions 18, 19, the thickness of which is less than an outer walls 21, 22, 23, 24 separating the channels 15, 17 from the flat sides 7, 8 and the narrow sides 9, 11, respectively - Th, 25 parallel to the flat sides 7, 8 arranged web, which contains the row 13 with the through channels 16. The width of the web 25 (measured perpendicular to the flat sides 7, 8) corresponds approximately to the width of the through channels 12, 14 measured in the same direction. The through channels 13, which are preferably arranged centrally in the web 25 in a straight row, are preferably round.

As illustrated in FIG. 3, an outer section is removed from the heat exchanger body 6 at its end 26 which is gripped by the connection piece 5, the web 25 remaining in place. In this way, an extension 27 is formed in the form of a rectangular tongue, which on the outside has a flat side parallel to the flat sides 7, 8. For example, this geometry can be achieved by milling an outer part, which comprises the outer walls 21, 23 and the intermediate walls 18, 19, from a cut-to-length piece of extruded aluminum profile with the cross section according to FIG. The associated connector 4 or 5 is illustrated separately in Figure 4. It is designed, for example, as a one-piece body which has a tubular extension 28 with a rectangular inner contour for receiving the heat exchanger body 6. The rectangular inner contour includes, for example, a flat side 29 on which the flat side 8 of the heat exchanger body 6 is located. The cross section of the insertion opening 31 defined by the flat side 29 and the other delimiting sides so far coincides with the cross section of the outer circumference of the heat exchanger body 6 agree that this can be inserted into the tubular extension 28 with little play or with little pretension.

An approximately cylindrical distributor chamber 32 adjoins the insertion opening 31 and is arranged parallel to a likewise cylindrical distributor chamber 33. The distributor spaces 32, 33 are connected to one another by a slot-like passage 34 which, as FIG. 3 shows, is provided for receiving the extension 27. Correspondingly, its cross section corresponds to the cross section of the outer circumference of the extension 27.

In an axial extension of the distribution spaces 32, 33, a connection area 36, 37 adjoins them, which is set up for connection to an external line. This can be fastened by means of a screw connection, a clamp connection or by other connection measures, such as welding, soldering, gluing etc. in a head 38 which surrounds the connection areas 36, 37. The connector 4, 5 is preferably made of a metal or a pressure-resistant plastic that can be integrally connected to the heat exchanger body 6. Not only must a fluid-tight connection between the heat exchanger body 6 and the wall of the insertion opening 31 be created, but also a fluid-tight connection between the extension 27 and the wall of the passage 34. For this purpose, the connection piece 4, 5 can be provided with one or more filling openings 39 which, for example, pass through a flat surface 40 of the passage 34 and through which a solder or an adhesive in the respective gap between the heat exchanger body 6 or the extension 27 and the respective surfaces the insertion opening 31 and / or the passage 34 is to be filled in, for example injected. In the present exemplary embodiment, the filling opening 39 is in the form of a only slot in the connector 5 arranged so that it opens into the passage 34. It is also possible to connect the filling opening here with a groove which surrounds the passage 34 and thus also the extension 27 like a ring and thus places the filled adhesive around the extension 27 like a ring. This is indicated schematically in FIG. 4. One or more similar grooves can surround the insertion opening 31 and, after the heat exchanger body 6 has been inserted, can be filled with adhesive from the outside through injection openings.

In the above description, it was assumed that the connecting pieces 4, 5 are formed in one piece. If necessary, however, they can also be formed in two or more parts. For example, the cross-hatched area in FIGS. 3 and 4 can be replaced by a parting line which longitudinally cuts through the connecting pieces 4, 5. Depending on the choice of material, the parting line can be closed by an adhesive or a solder and create a fluid-tight, mechanically firm connection between the parts of the connection piece 4, 5 and the heat exchanger body 6.

The heat exchanger 3 described so far works as follows:

Reference is made to FIG. 3, in which the compressor-side connector 5 is illustrated. The refrigerant conveyed by the refrigerant compressor 2 passes through the connection area 37 in compressed form into the distributor space 33, the free flow cross section of which is considerably larger than the free flow cross section of all the through channels 16 which open here. The compressed heat transfer fluid therefore divides relatively evenly on all through channels 16 and flows through them in the longitudinal direction.

At the same time, the through channels 12, 14 (FIG. 5) opening into the distribution space 32 deliver heat transfer fluid into the distribution space 32, which acts here as a collection space. The refrigerant fluid of the through channels 15, 17 thus flows in countercurrent to the refrigerant fluid in the through channels 16. With cooling of the heat transfer fluid flowing in the through channels 16, the refrigerant flowing in the through channels 15, 17 and flowing into the refrigerant compressor 2 heats up somewhat, whereby it is led out of its wet steam area and thereby freed from liquid droplets.

The "drying" achieved in this way, ie the heating of the refrigerant beyond its wet steam point, is very effective due to the distribution of the inflow channel over a large number of through-channels with a small individual cross-section. A distribution over more than ten, preferably more than 20, through-channels 15 becomes 17. In the present exemplary embodiment, there are 48 through-channels, which means that the inflowing heat transfer fluid can be heated to a small extent, thanks to the large inner surface of the heat exchanger, liquid refrigerant particles remain on the wall of the through-channels 15, 17 and evaporate there.

A modified profile of the heat exchanger body 6 is illustrated in FIG. It differs from that according to FIG. 5 by additional circular section channels 41, 42 provided on the narrow sides 9, 11, which overall lead to an oval cross section of the outer contour of the heat exchanger body 6. The advantage of this leadership form is in the elimination of sharp edges between the flat sides 7, 8 and the narrow sides 9, 11, which on the one hand facilitates the production of the contour of the insertion opening 31 and on the other hand its sealing.

While maintaining the outer contour according to FIG. 6 or also starting from the outer contour according to FIG. 5, the heat exchanger body 6, as illustrated in FIG. 7, can be formed in two parts. For example, the web 25 can be manufactured as a separate part 43 which is inserted into a part 44. The latter only includes the outer walls 21, 22, 23, 24 and the intermediate walls 18, 19. There may be a slight play between the two parts 43, 44 in order to facilitate the insertion of the part 43 into the part 44. However, it is also possible to provide a press fit here in order to facilitate the heat transfer between the part 43 and the intermediate walls 18, 19. The intermediate walls 18, 19 can alternatively also be unshaped on the part 43. While the first-mentioned variant has the advantage that when connecting the connecting pieces 4, 5 no mechanical

Machining of the part 43 is necessary, the second variant has the advantage that the heat transfer between the part 43 and the intermediate walls 18, 19 is improved.

A heat exchanger 3, which is particularly suitable for the air conditioning system of a motor vehicle or other high pressure applications, has a heat exchanger body 6 in the form of a hollow profile body which has a plurality of through channels 15, 16, 17 arranged in rows and parallel to one another, the through channels in each case Arranged in rows so that by removing portions of the heat exchanger body 6, the mouths of the through channels 15, 17 axially offset against the mouths of the through channels 16 can be. This creates the prerequisite for a geometrically simple and flow-favorable connection piece, which combines the mouths of the through channels 15, 17 into one collecting chamber and the mouths of the through channels 16 into another collecting chamber.

Claims

Claims:

1. Heat exchanger (3) with a heat exchanger body (1) which has two opposite flat sides (7, 9) and in the through channels (15, 16, 17), in at least two rows parallel to the flat sides (7, 8) ( 12, 13, 14) are arranged, and with connecting pieces (4, 5) at both ends of the heat exchanger body (6), via which at least the through channels (15, 17) one of the rows with a connection (36) and the through channels (16 ) of the other row are connected to another connection (37).

2. Heat exchanger according to claim 1, characterized in that the through channels (15, 16, 17) in the heat exchanger body (6) are arranged in three rows (12, 13, 14).

3. Heat exchanger according to claim 2, characterized in that the rows (12, 13, 14) are straight and parallel to each other.

4. Heat exchanger according to claim 2, characterized in that the through-channels (15, 17) of the outer rows (12, 14) with one connection (36) and the through-channels (16) of the inner row (13) with the other connection ( 37) are connected.

5. Heat exchanger according to claim 1, characterized in that the through channels (15, 17) connected to the one connection (36) each have a larger flow. mung cross section than the through channels (16) connected to the other connection (37).

6. Heat exchanger according to claim 1, characterized in that the through channels (15, 17) connected to the one connection (37) taken together have a larger flow cross-section than the through channels (16) connected to the other connection (37) taken together.

7. Heat exchanger according to claim 1, characterized in that the heat exchanger body (6) is constructed in one piece.

8. The heat exchanger according to claim 1, characterized in that the heat exchanger body (6) is constructed in two parts from an inner part (43), which only surrounds inner through channels (16), and an outer part (44), which only has outer through channels (15, 17 ) surrounds.

Heat exchanger according to claim 1, characterized in that at the ends of the heat exchanger body (6) in each case a connection extension (27) is formed, which contains a row (13) of through channels (16).

10. Heat exchanger according to claim 9, characterized in that the connecting pieces (4, 5) each have a connecting surface (29) for the outside of the heat exchanger body (6) and a connecting surface (40) for the connection extension (27).

11. Heat exchanger according to claim 10, characterized in that at least one of the connecting surfaces (27, 40) is penetrated by at least one opening (39) for filling in a connecting means.

12. Heat exchanger according to claim 11, characterized in that the connecting means is a solder or an adhesive.