DE3927955A1 - Heat exchanger for motor vehicle heating system - has parts made of thermoplastics fastened together with adhesive and welding - Google Patents

Abstract

The heat exchanger for the heating circuit for the air-conditioning or heating circuit of a private car consists of a block of finned tubes (1,2) mounted between two header tanks (3,4). The header tank (3) is connected to the return flow pipe (13) and a supply pipe (13') is connected to either of the tanks (3,4). A through-flow pipe (14) connects the two header tanks (3,4 This through flow pipe (14) and the header tanks (3,4) are made of plastics preferably a thermo-plastic material. The through flow pipe (14), the walls (6,8) of the header tanks (3,4) and the cover (5,7) are fastened together by plastic deformation, by bonding with adhesive or by welding. USE - Heating exchangers for motor vehicle heating systems.

Description

The invention relates to a heat exchanger of a heating circuit for motor vehicles, especially an air conditioning or heating system for passenger cars, with at least one tube block, the is arranged between two water boxes, at least one Return line to one of the water tanks and at least one Inlet line can be connected to the other water tank with at least one flow line connected to one of the water tanks connected and especially in the area of the other water tank with a supply or return connection for the supply or Return line is provided.  

A heat exchanger of the type mentioned at the beginning is used, for example Cars used to the vehicle interior warm up. In special embodiments with two Pipe rib blocks, the left and the right Vehicle interior are warmed up differently; there is regulated by the vehicle occupants whether and how much Heat exchange medium, which via a common flow line, which in this case is connected to the feed line and thus represents a flow line, one of the water tanks is supplied and after flowing through the individual Pipe fin blocks through the return lines on the other Water box are connected, is discharged.

Heat exchangers described in this way are known (DE 34 03 335 A1, G 84 02 761.4), but have several disadvantages. The Heating of the radiation fins and thus that of the heat exchanger Air flowing through should only pass through the pipes of the individual heat exchanger fluids respectively.

Due to the use of a metallic flow line and the arrangement of these within the tube fin blocks, thermal decoupling measures must be taken to a heat influence of the fins through the flow line to diminish. With the known heat exchangers must therefore the flow line is shielded from any air flow be, for example, by means of a cover and through Spacing and corresponding shaping of the edges of the  Ribs are made in the area of the flow line.

Another disadvantage is that special Sealing measures when fastening the flow line with the water tank are necessary, so that the tightness of the Joint is guaranteed even at higher operating pressures.

The invention has for its object a heat exchanger of the type mentioned in such a way that the described disadvantages are avoided, one more effective thermal decoupling of the flow line from the tube fin blocks is made possible and an improved Fixing the flow line in the water tank without additional sealing measures are guaranteed.

To solve this problem it is provided that the Flow line and the water tanks are made of plastic, especially from a thermoplastic, and that the Flow line with the tube sheet of the water tank as well as the Pipe trays with the covers of the water tanks through plastic Deformation, by gluing or by welding are connectable. By using a Plastic flow line and plastic water tanks can not just a cheaper manufacture of the heat exchanger achieved in metallic execution compared to the previous ones be, but it is also possible to use the flow line with a correspondingly low construction effort  with no clearance to the fins between the tube fin blocks lead and further measures to shield the line from the passage air flow, as the Heat transfer through the plastic pipe not to the extent takes place, as is the case with the previous metal versions of the Case is. The use of the connection methods described for the connection of the water box parts to each other as well between the tube sheet of the water tank and the Flow line on the other hand also result in a secure, connection between the parts that can no longer be sealed. These joining and joining methods are also extreme easy to integrate into automated production processes, so that another cost reduction in manufacturing such described heat exchanger is possible.

A compact design of the heat exchanger can can be achieved in that the water boxes one above the other can be arranged that the upper water tank at least can have a return connection to the connections of Return lines are attachable, and that a Flow line centrally between two parallel Pipe fin blocks running as a flow line with the lower one Water tank can be connected and in the area of the upper Water box with an inlet connection for the inlet line is provided.

The fact that two separate heating circuits can be assigned  juxtaposed tube fin blocks can be provided can, whose common ribs by parallel to Airflow direction slots completely or are partially separated that the upper water tank two separate chambers, each with a return line and the lower water tank a common chamber for one Can have inlet line, and that the flow line through cross-sectional recesses in the ribs runs between the tube fin blocks, it is possible to get one Heat exchanger of the type mentioned in motor vehicles so that the left and right The interior of the vehicle can have different temperatures and thus a compact design of the heat exchanger is given.

A cheap joining method around the flow line with the To connect water box is achieved in that Tube bottom of the lower water tank a continuous, the Cross-section of the flow line adapted recess can be provided in the one end of the flow line protrudes and in this preferably by ultrasound or Friction welding is attachable. The advantage of Ultrasonic welding is that tube sheet and Pass line at the contact point briefly and be heated evenly so that a uniform sealing Connection of the joining surfaces is created. This can also be done be achieved that the flow line with one end through on the tube plate of the lower water tank  Welding can be fastened and the one Adapted internal cross section of the flow line, through the Enclosed tube bottom enclosing recess. To one Center the flow line above that in the tube sheet intended to facilitate recess and improved It is to ensure connection of the two parts to each other advantageous that the joining surfaces between the end of the Flow line and the tube sheet in the form of a Tongue-groove connection can be designed.

It is for a favorable use of space in the heat exchanger favorable that the flow line between the Pipe fin blocks through a sealed bushing between runs through the chambers of the upper water tank and in an incision area of the water tank between the chambers can be angled. It is therefore possible to make the connections for the supply lines and the return lines all on provide upper water tank, so that in addition only on upper water tank connection work can be carried out need. The latter advantage can also be achieved by that the upper water tank one between the chambers may have extending manifold that with a Inlet connection for the inlet line and one between the Pipe rib blocks lying, running through the tube sheet Recess is provided for receiving and attaching the upper end of the straight running between the water tanks Continuous line serves. It is particularly advantageous that the  Manifold integrated on the lid of the upper water tank can be integrally formed and in a sealing manner with a channel of the recess extending through the tube sheet. This allows a separately provided manifold, as well save its assembly, with an additional advantage in it there is that no special sealing measures between Lids and bends need to be made. The wall of the manifold that forms the channel and the recess is enclosed with its end face with the tube sheet connected by welding or gluing.

To two completely separate heating circuits in one It is special to integrate the heat exchanger unit advantageous that two separate flow lines are provided can be, each to the side of the tube block are continuously connected to the lower water tank and in Area of the upper water tank with inlet connections for two separate supply lines are provided. This is it possible, heat exchange media from two separate circuits to the common via the corresponding flow lines feed lower water tank, mix there and in further course of the individual tube fin blocks depending on the each set flow rate. It is also conceivable that the lower water tank like the upper one Water box two separate chambers has, so that each tube fin block from a separate Continuous line is supplied and via the separated  return lines to be provided for the upper water tank can be disposed of.

It goes without saying that in reverse the structural Arrangement made all connections on the lower water tank can be. This depends on the installation conditions for such a heat exchanger described. It is still too notice that the flow line is depending on the type of connection Flow line to the lower or upper water tank serves and can be connected to the supply line or as Follow-up pipe from the lower or upper water tank serves and can be connected to the return line.

The further features and advantages of the invention result from the following description of the drawings illustrated embodiments and the subclaims.

Fig. 1 is a schematic three-dimensional view showing a heat exchanger with a connected to the lower plenum chamber serving as a forward flow pipe, which is angled through the upper plenum chamber extending in the upper region,

Fig. 2 is a schematic three-dimensional view of the heat exchanger in a second variant in which the serving as the forward flow pipe is connected to the lower plenum and opens into a manifold of the upper water tank,

Fig. 3 is a vertical longitudinal section through the heat exchanger of Fig. 2, when viewed along the arrows III-III,

Fig. 4 shows a horizontal cross section through the heat exchanger of Fig. 2, when viewed along the arrows IV-IV,

Fig. 5 shows a three-dimensional view of another variant of a heat exchanger with two extending at the transverse sides of the heat exchanger as a rectangular flow passage serving lines,

Fig. 6 shows a cross section of a first embodiment of the connection between the tube bottom of the water tank and the transfer pipe,

Fig. 7 shows a second variant of the connection of the tube bottom of the water tank with the pass line,

Fig. 8 shows a third variant of the connection between the tube bottom of the water box and the not yet secured therein pass line,

Fig. 9 shows another variant of the possible joining zone forming between the tube bottom and the lid of the water tanks in accordance with the details IX and X in Fig. 3.

The heat exchanger shown in FIGS. 1, 2, 5 is used for the heating or air conditioning of a passenger car, for example to enable different heating of the left and right vehicle interiors. For this purpose, the heat exchanger has two tube fin blocks 1 and 2 arranged side by side, which are each formed from a multiplicity of parallel tubes 9 , on which transverse thin fins 10 are fastened. The fins 10 and the tubes 9 are made of aluminum. The ends of the vertically directed tubes 9 , which are alternatively provided with turbulence inserts 30 , open into an upper water tank 3 and a lower water tank 4 . The water boxes 3, 4 are preferably produced as two-part injection molded parts made of a plastic, in particular of a heat-resistant thermoplastic that can be welded well. However, other plastics can also be used for the production. The lower water tank 4 consists of a tube sheet 8 and a cover 7 , which each have a circumferential connecting flange 25 and 26 and are connected via these. A possible configuration of the joining zones between the flanges 25, 26 is shown in FIG. 3 and in another variant in FIG. 9. The joining of the cover 7 to the tube sheet 8 can be accomplished by welding, gluing or other suitable joining methods, a continuous connecting seam being created which makes an additional seal between the parts 7, 8 superfluous. In the tube sheet 8 , the lower ends of the tubes 9 are received in bores of the same cross section and in particular are sealingly received in the mouth region by widening or pressing in their ends.

The upper water tank 3 largely corresponds to the lower water tank 4 , with the difference that, in contrast to the only one chamber 11 '' design of the lower water tank 4 , is provided with two chambers 11, 11 ' . To form the chambers 11, 11 ' , as shown in Fig. 5, the lid 5 of the upper water tank 3 has a partition 24 which is sealingly connected to the tube sheet 6 , so that two preferably equally large chambers 11, 11' are trained. Other embodiments are shown in Fig. 1 and 2, wherein there the cover 5 has a cool-like incision area 27 transverse to the longitudinal direction of the water box 3 , whereby the chambers 11, 11 ' are separated from each other by a free space. The chambers 11, 11 ' are each provided with a return connection 13, 13' , to each of which a return line for the heat exchange medium can be connected. The tubes 9 are received in the tube sheet 6 in the same manner as in the tube sheet 8 of the lower water tank 4 .

In order to supply the lower water tank 4 with the heat exchange medium, for example with the cooling water of the motor vehicle (when used as a radiator), a flow line 14 is provided which runs parallel to the tubes 9 of the tube fin blocks 1, 2 in the area of the upper water tank 3 can be connected to a feed line via a corresponding feed connection 12 . Therefore, the flow line 14 serves as a so-called flow line. As shown in FIGS . 1 to 4, the flow line 14 is arranged to run between the tube fin blocks 1, 2 and is designed in the form of a cylindrical tube. The flow line 14 , which is made of a plastic, in particular a thermoplastic, can be connected to the tube sheet 8 of the lower water tank 4 by means of different joining methods. If the tube sheet 8 and the flow line 14 consist of the same thermoplastic, ultrasonic welding and the friction welding process are particularly suitable for this. Other types of sealing attachment of the flow line 14 to the tube sheet 8 include, among other things, gluing the ends of the flow line in a corresponding hole in the tube sheet. As shown in FIGS. 6 to 8 in more detail, various embodiments of the connection between the tube sheet 8 and the flow line 14 are possible.

In FIG. 7, the tube sheet 8 has a continuous recess 15 adapted to the cross section of the flow line 14 , into which the end of the flow line 14 projects. The cross-sectional dimension of the recess 15 is generally slightly larger than the outer dimension of the flow line 14 . The flow line 14 can be introduced into the recess 15 so that the line end either protrudes from the end face of the tube sheet 8 or is flush with it; it is also conceivable that the end ends below the end face. When using ultrasonic welding, the contact point between tube sheet 8 and flow line 14 is briefly uniformly heated, so that a largely homogeneous welding takes place.

Another embodiment of the connection between the tube sheet 8 and the flow line 14 is shown in FIG. 6; there the end of the flow line 14 is attached to the end of the tube sheet 8 with this, for example. By rotational friction welding or a similar welding method. The tube sheet 8 has an internal cross section of the flow line 14 adapted through recess 15 ' which forms an access channel to the lower water tank 4 in the extension of the flow line 14 . To center the flow line 14 with the recess 15 ' , the tube sheet 8 has a ring around the recess 15' arranged centering lug 18 ' which engages in a correspondingly shaped receiving face 17 formed on the end of the flow line 14 ' . Thus corresponds to a tongue and groove connection, which is designed geometrically so that it, adapted to the welding requirements, enables a sealing and secured connection between the tube sheet 8 and the flow line 14 . In FIG. 8, a further connection area is shown in which the tube sheet having a 8 the cross-section of transfer pipe 14 is approximately matched connecting piece 16, on which the transfer pipe 14 is mounted sealingly end face. For this purpose, in a modification of the embodiment according to FIG. 6, the connecting piece 16 has an annular receiving groove 17 into which a fastening lug 18 integrally formed on the end face at the end of the flow line 14 engages.

Other types of connection are also conceivable, for example Provide appropriately designed flanges by Screwing or the like.

The flow line 14 connected to the tube sheet 8 of the lower water tank 4 runs in the heat exchanger embodiment shown in FIG. 1 through a cross-section-adapted passage 19 of the upper water tank 3 , which is formed in the incision area 27 between the chambers 11, 11 ' . The flow line 14 is angled in the incision area 27 such that the supply and return lines are connected only on one side of the heat exchanger. This provides a particularly compact embodiment of the heat exchanger, an additional advantage being that connection work only needs to be carried out on the upper water tank 3 .

In another embodiment of the heat exchanger ( Fig. 2, 3), the upper water tank 3 has an elbow 20 arranged in the incision area 27 between the two chambers 11, 11 ' . In the embodiment shown here, this is integrated on the lid 5 of the upper water tank 3 , but can also be a separate component. The tube sheet 6 has a lying between the pipe ribs blocks 1, 2-receiving opening 21 which is adapted to the cross-section of the pipe 14 and serving to receive the straight extending between the header tanks 3, 4 pass line fourteenth The passage line 14 can be fastened in the tube sheet 6 by one of the connection types already described. The upper mouth area of the flow line 14 in the tube sheet 6 is sealed by the elbow 20 . The channel 22 formed in this way opens into an inlet connection 12 to which the inlet line can be connected.

In FIG. 5 another embodiment of the heat exchanger is shown; this has two separate flow lines 14 ', 14'' , which are arranged on the side of the tube block 1 and 2 , and in the area of the upper water tank 3 with separate inlet connections 12' are provided. This makes it possible to supply the heat exchange medium through two separate feed lines, as a result of which the control options of the two separate circuits for influencing the heat exchange can be significantly increased. In the embodiment shown, the flow lines 14 ', 14''have a rectangular, optionally multiply subdivided cross-section and are connected to the tube sheet 8 of the lower water tank 4 in a manner similar to that described above. The flow lines 14 ', 14'' run through cross-sections corresponding bushings 19' on the transverse sides of the upper water tank 3 and can optionally be connected to this to increase the connection rigidity. Due to the selected design of the flow lines 14 ', 14'' , these simultaneously form two lateral guide surfaces 23, 23' , so that the normally provided angling of the edges of the ribs 10 (see FIG. 3) to achieve a closed air flow area through the heat exchanger is eliminated can.

The via the transfer pipe 14 or 14 ', 14''to the lower water box 4 supplied heat exchange medium is distributed in the lower plenum 4 to the two pipe ribs blocks 1 and 2. FIG. The return connections 13, 13 ' are assigned control valves through which the respective return quantity can be set so that the finned tube blocks 1 and 2 are flowed through at different speeds and thus have different temperatures. In order to prevent a mutual influence of temperature between the tube fin blocks 1 and 2 , they each have their own fins 10 or the fins 10 are divided by slots 28 running parallel to the air flow direction in the separation area of the tube fin blocks 1 and 2 . Since the flow lines 14, 14 ', 14''are made of plastic and are therefore poor heat conductors, special protective measures that reduce the temperature influence between the flow line 14, 14', 14 '' and the ribs 10 are unnecessary. A direct investment of these parts is possible. The flow line 14 arranged centrally between the tube fin blocks 1 and 2 runs through recesses 29 in the fins 10 which correspond to the cross section, without maintaining a particular distance from them.

The described embodiments have in common the choice of Plastic as a manufacturing material for the water tanks and for the flow line. This makes it essential Manufacture cheaper heat exchangers, because the possible thereby Connection and joining methods compared to the previous ones Execution types allow for additional complex To avoid sealing measures as far as possible mutual thermal influence of the flow line with the tube rib blocks significantly reduced, so that additional Protective measures can be omitted.

Other embodiments of the heat exchanger are possible  where two return lines and only one inlet line or only one inlet and one return line are provided. This depends on the application requirements for the Heat exchanger, d. H. whether separate circuits or a common cycle is needed.

Here, it is also conceivable to reverse the structural Arrangement of the connections for the supply and return lines to make. The connections can also all be at the bottom Water tank take place, or the flow direction of the Heat exchange medium through the heat exchanger can be reversed be so that the flow line is no longer a so-called. Supply line to the lower or upper water tank, but represents a follow-up pipe to which the Return line is connectable.

Claims (12)

1. Heat exchanger of a heating circuit for motor vehicles, in particular an air conditioning or heating system for motor vehicles, with at least one tube fin block ( 1, 2 ) which is arranged between two water boxes ( 3, 4 ), at least one return line to one of the water boxes ( 3 ) and at least one inlet line can be connected to the other water box ( 3, 4 ), with at least one flow line ( 14 ) connected to one of the water boxes ( 3, 4 ) and in particular in the area of the other water box ( 3, 4 ) with a closing line - Or return connection ( 12, 13 ) is provided for the supply or return line, characterized in that the flow line ( 14 ) and the water boxes ( 3, 4 ) consist of plastic, in particular a thermoplastic, and that the flow line ( 14 ) with the tube sheet of the water tank ( 3, 4 ) and the tube sheets ( 6, 8 ) with the cover ( 5, 7 ) of the water tank ( 3, 4 ) by plastic deformation, by Gluing or can be connected by welding. 2. Heat exchanger according to claim 1, characterized in that the water tanks ( 3, 4 ) are arranged one above the other, that the upper water tank has at least one return connection ( 13, 13 ' ), can be fastened to the connections of return lines, and that a through line ( 14 ) running in the middle between two parallel tube fin blocks ( 1, 2 ) is connected as a flow line to the lower water tank ( 4 ) and in the area of the upper water tank ( 3 ) is provided with an inlet connection ( 12 ) for the inlet line. 3. Heat exchanger according to claim 1 or 2, characterized in that two, separate heating circuits assignable, juxtaposed tube fin blocks ( 1, 2 ) are provided, the common fins ( 10 ) are completely or partially separated by parallel to the air flow direction slots ( 28 ) that the upper water tank ( 3 ) has two separate chambers ( 11, 11 ' ) for a return line and the lower water tank ( 4 ) has a common chamber ( 11'' ) for an inlet line, and that the flow line ( 14 ) by cross-section accordingly Recesses ( 29 ) of the ribs ( 10 ) between the tube fin blocks ( 1, 2 ). 4. Heat exchanger according to one of claims 1 to 3, characterized in that in the tube sheet ( 8 ) of the lower water tank ( 4 ) a continuous, the cross section of the flow line ( 14 ) adapted recess ( 15 ) is provided, in which one end of the flow line ( 14 ) protrudes and can be fastened therein, preferably by ultrasound or friction welding. 5. Heat exchanger according to one of claims 1 to 3, characterized in that the flow line ( 14 ) can be fastened at one end to the tube sheet ( 8 ) of the lower water tank and one adapted to the internal cross section of the flow line ( 14 ) through the tube sheet ( 8 ) enclosing the recess ( 15 ' ). 6. Heat exchanger according to claim 5, characterized in that the tube sheet ( 8 ) of the lower water tank ( 4 ) has a around the recess ( 15 ' ) connecting piece ( 16 ) on which the flow line ( 14 ) can be fastened at the end, in particular by Friction welding or ultrasonic welding. 7. Heat exchanger according to one of claims 5 or 6, characterized in that the joining surfaces between the end of the flow line ( 14 ) and the tube sheet ( 8 ) are designed in the form of a tongue and groove connection. 8. Heat exchanger according to one of claims 3 to 7, characterized in that the flow line ( 14 ) between the tube fin blocks ( 1, 2 ) through a sealed passage ( 19 ) on the upper water tank ( 3 ) and in an incision area ( 27 ) of the Water box ( 3 ) between the chambers ( 11, 11 ' ) is angled. 9. Heat exchanger according to one of claims 3 to 7, characterized in that the upper water tank ( 3 ) has a bend ( 20 ) extending between the chambers ( 11, 11 ' ), which has an inlet connection ( 12 ) for the inlet line and one Between the tube block ( 1, 2 ) lying, through the tube sheet ( 6 ) extending recess ( 21 ) is provided, which serves to receive and fasten the upper end of the straight line ( 14 ) running between the water boxes ( 2, 3 ). 10. Heat exchanger according to claim 9, characterized in that the elbow ( 20 ) is integrally formed on the cover ( 5 ) of the upper water tank ( 3 ) and in a sealing manner a channel ( 22 ) with the through the tube sheet ( 6 ) extending recess ( 21 ) forms. 11. Heat exchanger according to one of claims 2 to 7, characterized in that two separate flow lines ( 14 ', 24'' ) are provided, each of which is laterally connected to the lower water box ( 4 ) and laterally of the tube fin blocks ( 1, 2 ) in the area of the upper water tank ( 3 ) are provided with inlet connections ( 12 ' ) for two separate inlet pipes. 12. Heat exchanger according to claim 11, characterized in that the cross-sectional shape of the flow lines ( 14, 14 ' ) in the tube fin block area is rectangular and each lateral guide surfaces ( 23, 23' ) for the air flowing through the tube fin blocks ( 1, 2 ).