EP2395295A1 - Heat exchanger - Google Patents

Abstract

The heat exchanger (1) has conductors (4) i.e. printed circuit boards (6, 7), connected with an electrical resistance heating element (2) i.e. positive temperature coefficient (PTC) element (3). Electrical insulating elements (22) i.e. gaskets (23), electrically insulate the conductors from heat conducting elements (11) i.e. corrugated ribs (12). The conductors and/or the heating element are arranged in a hollow space (19) defined by hollow space walls (17). The walls are designed as a closed pipe (18) with two joints (38) in a cross-section, where the pipe includes two pipe portions (39). An independent claim is also included for a method for manufacturing a heat exchanger or a motor vehicle air-conditioning system.

Description

The invention relates to a heat exchanger according to the preamble of claim 1, an automotive air conditioning system according to the preamble of claim 10 and a method for producing a heat exchanger or an automotive air conditioning system according to the preamble of claim 11.

Automotive air conditioning systems are used to heat and / or cool the air to be supplied to the interior of a motor vehicle. In motor vehicle air conditioning systems, heat exchangers are used as electrical heating devices in order to heat the air which is supplied to the interior. The electric heater includes PTC elements. Positive Temperature Coefficient (PTC) elements are current-carrying materials that have electrical resistance and can conduct electricity better at lower temperatures than at higher temperatures. Their electrical resistance thus increases with increasing temperature. The PTC element is generally made of ceramic and is a PTC thermistor. Thereby arises regardless of the boundary conditions - such. B. applied voltage, nominal resistance or air flow to the PTC element - a very uniform surface temperature at the PTC element. Overheating can be prevented as it z. B. could occur with a normal heat-emitting heating wire, since regardless of the boundary conditions always about the same resistance and thus a substantially identical electrical heating power is applied.

The heat exchanger comprises PTC elements, at least two electrical conductors by means of which electrical current is conducted through the PTC element and heat conducting elements, in particular fins or corrugated fins, by means of which the surface for heating the air is increased. Increasingly, motor vehicles are produced which have an exclusive electric drive or a hybrid drive. Automotive air conditioning systems for these motor vehicles generally no longer have a heat exchanger for heating the air through which cooling fluid flows. The entire heating power of the motor vehicle air conditioning system must therefore be applied by the electric heater or the PTC elements. For this reason, it is necessary, the PTC elements with high voltage, z. B. in the range of 50 to 600 volts instead of low voltage with 12 volts to operate. High voltage in an automotive air conditioning system, however, is a security problem because, for example, by a human touch of high voltage parts of the person from the high voltage health damage can be added.

The US 4,327,282 shows a heat exchanger with a PTC heating element. Current is passed through the PTC heating element by means of contact plates and an insulating layer is arranged on the contact plates. The components are held together by means of a U-shaped clip.

From the EP 1 768 458 A1 a heat generating element of a heater for air heating is known, comprising at least one PTC element and voltage applied to opposite side surfaces of the PTC element electrical conductor tracks, wherein the two electrical conductors are surrounded on the outside by a non-electrically conductive insulating layer.

The object of the present invention is therefore to provide a heat exchanger and an automotive air conditioning system and a method for producing a heat exchanger and an automotive air conditioning system, in which a with electric current under high voltage, for. B. more than 50 V, operated heat exchanger without endangering the environment, especially people, can be operated. The heat exchanger and the vehicle air conditioning should be inexpensive to manufacture reliable in operation.

This object is achieved with a heat exchanger comprising at least one electrical resistance heating element, in particular at least one PTC element, at least two conductors electrically connected to the at least one electrical resistance heating element, in particular printed circuit boards, in order to conduct electrical current through the at least one electrical resistance heating element and thereby to heat the electrical resistance heating element, at least one heat conducting element for transmitting heat from the at least one electrical resistance heating element to a fluid to be heated, at least one electrical insulating element electrically isolating the at least two conductors, preferably from the at least one heat conducting element, the at least two conductors and / or the at least one electrical resistance heating element is arranged in at least one cavity bounded by at least one cavity wall and the at least one electrical resistance heating element is arranged at least one cavity Insulating element is at least one molded seal, wherein the at least one cavity wall is formed as at least one closed tube with at least two joints in cross section and preferably the at least one tube comprises at least two pipe parts.

In particular, the at least two joints by means of a biasing force, for. B. by clips, and / or a flanging and / or bonding and / or welding and / or soldering of at least two pipe parts.

In a further embodiment, the at least one tube is formed by two U-shaped shells in cross section or the at least one tube is formed by a respective tub and plate.

In a supplementary embodiment, the at least one tube is designed as at least one flat tube with two broad side walls and two narrow side walls.

Preferably, the at least one molded gasket is disposed between each of a wall of the at least one tube and a conductor, so that the at least two conductors are electrically insulated with respect to the at least one tube.

In one variant, two, preferably substantially rectangular, shaped seals are arranged in the cavity, or the at least one molded seal is formed in the cavity as a tube, in particular a shrink tube

Suitably, the at least one molded seal is elastic and / or the at least one molded seal consists at least partially of silicone or plastic or rubber and / or the at least one molded seal is with the at least one tube positively and / or positively and / or materially connected and / or the at least one molded seal is a film.

In a further embodiment, the at least one molded seal comprises heat-transmitting or thermally conductive particles, for. For example, alumina and / or silicon carbide and / or boron nitride, and / or the at least one tube is from a first, z. B. upper, cover plate at a first end, in particular fluid-tight, closed and / or the at least one tube is of a second, z. B. lower, cover plate at a second end, in particular fluid-tight, closed.

In particular, the at least one electrical resistance heating element, the at least two conductors and the at least one molded seal connected to at least one heating composite, which or which is disposed within the at least one tube or are and preferably form a plurality of tubes each having a heating composite and arranged between the tubes Corrugated ribs the heat exchanger, wherein, in particular by means of a clamping frame or a spring, on the walls of the at least one tube, in particular the broad side walls of the at least one flat tube, a compressive force is applied, so that due to the compressive force of the heating composite frictionally against the two walls, in particular Breitseitenwandungen , fastened, in particular clamped, is.

An automotive air conditioning system according to the invention comprises at least one heat exchanger described in this patent application

Inventive method for producing a heat exchanger or a motor vehicle air conditioning system, in particular a heat exchanger described in this patent application or an automotive air conditioning system described in this patent application, comprising the steps of: providing at least one electrical resistance heating element, in particular at least one PTC element, providing at least two electrical conductors, in particular printed circuit boards, for passing electrical current through the at least one electrical resistance heating element, providing at least one heat conducting element for transmitting heat from the at least one electrical resistance heating element to one heating fluid, providing at least one electrical insulating element as a molded gasket for electrically insulating the at least one heat conducting element from the at least two conductors, connecting the at least two conductors to the at least one electrical resistance heating element, thermally bonding the at least one heat conducting element to the at least one conductor, and / or with the at least one electrical resistance heating element, electrically insulating the at least two conductors, preferably of the at least one heat conducting element, by means of at least a molding gasket, by connecting the at least two conductors to the at least one electrical resistance heating element and the at least one molded gasket to at least one heating composite, providing at least one pipe, the at least one heat conducting element comprising at least one cavity wall, which encloses at least one cavity and the at least one cavity wall is formed as a wall of the at least one tube, wherein the at least one tube is made available from at least two tube parts and the at least two tube parts are connected to the at least one tube.

In a further embodiment, the at least two pipe parts by means of clips, soldering, gluing or welding, in particular fluid-tight, connected.

In a supplementary variant, the at least one heating composite is introduced into the at least one cavity before joining the at least two pipe parts.

In a further variant, after the at least one heating composite is introduced into the at least one cavity, a force is applied to at least one wall of the tube so that the at least one heating composite is frictionally secured between two walls of the at least one tube and direct contact between the two Walls and the molded gasket of Heizverbundes is produced.

In a further embodiment, the at least one molded seal is formed as a shrink tube and the shrink tube is shrunk onto the at least one heating composite by the shrink tube is heated.

In one variant, the at least one heat-conducting element comprises at least one tube and / or the at least one heat-conducting element comprises corrugated ribs, which are arranged on the outside of the at least one tube, in particular by means of soldering or gluing, and / or the at least two conductors have no direct contact the at least one pipe.

Expediently, the at least one heat-conducting element, in particular the at least one tube and / or the corrugated ribs, at least partially, in particular completely, consists of metal, for example aluminum or steel, or plastic.

The at least one molded seal consists of an electrically insulating and thermally conductive material. Due to the geometric arrangement of the at least one molded seal within the heat exchanger, the at least two conductors and the at least one electrical resistance heating element are electrically insulated. The molded seal is in a solid Physical state, ie not liquid or gaseous, even at high temperatures, eg. 70 ° C or 100 ° C.

In a further embodiment, the at least one molded seal is a film or insulating film, for. Example, a polyimide film (Kapton film), (elastic) ceramic-filled film or a (elastic) ceramic-filled silicone film.

In an additional variant, the heat exchanger has an IP protection class of 67, so that a sufficient waterproofness and dust tightness is present.

A closed pipe is a pipe whose walls are completely closed in a cross section.

In a further embodiment, the corrugated fins and the at least one tube are connected to each other by means of gluing and / or soldering and / or non-positively under prestress.

In a further embodiment, the first and / or second sealing plate has a groove, in which one end of the at least one tube is arranged.

In a further variant, the at least one tube in the groove with a seal, z. B. a, preferably elastic seal, or an adhesive, sealed.

In a further embodiment, when the volume of the at least one cavity is reduced, the at least one molded seal is elastically deformed due to contact between the at least one cavity wall and the at least one molded seal and by the elastic Forces of at least one mold seal after the elastic deformation, the at least one mold seal non-positively connected to at least one wall of the at least one tube, in particular the at least one molded seal is clamped between two walls.

In a further embodiment, the at least one heat-conducting element and / or the at least one molded seal has a thermal conductivity of at least 1 W / mK, in particular at least 15 W / mK.

In a further embodiment, the at least one molded seal has an electrical insulation of at least 1 kV / mm, in particular at least 25 kV / mm.

In a variant, the at least one molded seal, preferably in cross section, has a dielectric strength of at least 1 kV.

In a further embodiment, the at least one molded seal has a thermal conductivity of at least 1 W / mK, in particular at least 15 W / mK. On the one hand, the at least one molded seal can thus insulate well electrically and, on the other hand, can sufficiently conduct the heat from the electrical resistance heating element to the heat-conducting element or the heat-conducting elements.

Fig. 1

einen Querschnitt einer Kraftfahrzeugklimaanlage,

Fig. 2

eine perspektivische Ansicht eines Wärmeübertragers ohne Deckplatten bzw. mehrerer Heizregister,

Fig. 3

eine Seitenansicht des Wärmeübertragers gemäß Fig. 2,

Fig. 4

eine Draufsicht des Wärmeübertragers gemäß Fig. 2,

Fig. 5

eine perspektivische Ansicht des Wärmeübertragers gemäß Fig. 2 mit Deckplatten ohne Heizeinheiten,

Fig. 6

eine Explosionsdarstellung des Wärmeübertragers gemäß Fig. 5,

Fig. 7

einen Querschnitt eines Heizregisters,

Fig. 8

einen weiteren Querschnitt des Heizregisters gemäß Fig. 7,

Fig. 9

eine Explosionsdarstellung des Heizregisters,

Fig. 10

eine perspektivische Ansicht des Wärmeübertragers ohne Deckplatten in einem ersten Ausführungsbeispiel,

Fig. 11

eine perspektivische Ansicht des Wärmeübertragers ohne Deckplatten in einem zweiten Ausführungsbeispiel,

Fig. 12

einen Querschnitt zweier Halbschalen vor dem Fügen,

Fig. 13

einen Querschnitt der Halbschalen gemäß Fig. 12 mit einer Heizeinheit während des Zusammenführens der Halbschalen,

Fig. 14

einen Querschnitt des Rohres gemäß Fig. 12 nach einem Zusammenfügen der Halbschalen mit der Heizeinheit,

Fig. 15

eine perspektivische Ansicht des Rohres aus zwei Halbschalen mit Clipsen,

Fig. 16

eine Explosionsdarstellung einer Wanne und einer Platte vor dem Zusammenfügen zu dem Rohr,

Fig. 17

einen Querschnitt des Rohres aus der Wanne und der Platte gemäß Fig. 16 nach dem Zusammenfügen,

Fig. 18

einen Längsschnitt des Heizregisters.

Hereinafter, embodiments of the invention will be described in more detail with reference to the accompanying drawings. It shows:

Fig. 1

a cross section of an automotive air conditioning system,

Fig. 2

a perspective view of a heat exchanger without cover plates or multiple heating coil,

Fig. 3

a side view of the heat exchanger according to Fig. 2 .

Fig. 4

a plan view of the heat exchanger according to Fig. 2 .

Fig. 5

a perspective view of the heat exchanger according to Fig. 2 with cover plates without heating units,

Fig. 6

an exploded view of the heat exchanger according to Fig. 5 .

Fig. 7

a cross section of a heating register,

Fig. 8

a further cross section of the heater according to Fig. 7 .

Fig. 9

an exploded view of the heating register,

Fig. 10

a perspective view of the heat exchanger without cover plates in a first embodiment,

Fig. 11

a perspective view of the heat exchanger without cover plates in a second embodiment,

Fig. 12

a cross section of two half-shells before joining,

Fig. 13

a cross-section of the half-shells according to Fig. 12 with a heating unit during the bringing together of the half-shells,

Fig. 14

a cross-section of the pipe according to Fig. 12 after assembling the half-shells with the heating unit,

Fig. 15

a perspective view of the tube of two half-shells with clips,

Fig. 16

an exploded view of a tub and a plate before joining to the tube,

Fig. 17

a cross section of the tube from the tub and the plate according to Fig. 16 after joining,

Fig. 18

a longitudinal section of the heater.

Fig. 1 shows an automotive air conditioning 24. In an air conditioning case 26 having a bottom wall 27 and an outlet portion 29, a fan 25, an air filter 30, a refrigerant evaporator 31 and a heat exchanger 1 is arranged as an electric heater. The air conditioning housing 26 thus forms a channel 35 for passing the air. Housing walls 28 of the air conditioning housing 26 have on the inside a surface 36 which define the channel 35. The air for the interior of a motor vehicle is passed by means of the blower 25 through the air filter 30, the refrigerant evaporator 31 and the heat exchanger 1.

The automotive air conditioning system 24 is thus not provided with a heat exchanger through which coolant flows for heating the air conducted through the motor vehicle installation 24. The air conducted by the motor vehicle air conditioning system 24 is electrically heated exclusively by means of the heat exchanger 1. The motor vehicle air conditioning system 24 is preferably used in a motor vehicle with exclusively electric drive or with a hybrid drive (not shown). In order to achieve the necessary electrical heating power by means of the heat exchanger 1, the heat exchanger 1 with high voltage, z. B. with more than 50 volts, for example, 60 V or 600 V, operated to not too large Amperages and thus too thick power lines (not shown) to get.

In the Fig. 2 to 18 Embodiments of the heat exchanger 1 for the motor vehicle air conditioner 24 are shown. An aluminum tube 18 designed as a flat tube 13 has two broad side walls 20 and two narrow side walls 21 (FIG. Fig. 8 and 14 ) on. The width and narrow side walls 20, 21 thereby represent cavity walls 17, which enclose a cavity 19 within the tube 18. The width and narrow side walls 20, 21 of the tube 18 are thus walls 16 of the tube 18. In this case, the walls 16 and cavity walls 17 have in cross-section two joints 38 (FIG. Fig. 8 . 14 and 17 ) on. The tube 18 is made in two parts from two tube parts 39.

Within the flat tube 13, two molded seals 23 are arranged as electrical insulating elements 22. The two form seals 23 are made of elastic silicone. On the two rectangular shaped seals 23 according to Fig. 7, 8 . 12, 13 . 14 and 16 are two conductors 4, namely a first circuit board 6 and a second circuit board 7, on. Between the two circuit boards 6, 7 three PTC elements 3 designed as electrical resistance heating elements 2 are arranged. The PTC elements 3 are connected to each other with the two printed circuit boards 6, 7 with adhesive. At the two conductors 4, an electrical contact plate 5 is formed in each case ( Fig. 2 and 3 ). The cavity 19 enclosed by the cavity walls 17 of the flat tube 13 is a void 32 in the region of the narrow side walls 21, ie in the void 32 only air ( Fig. 8 ). Deviating inside a heating register 9, the shaped seal 23 can also be designed in one piece as a hose 34, in particular a shrinking hose ( Fig. 9 ).

As a result, the two printed circuit boards 6, 7 with the interposed three PTC elements 3 due to the electrical insulation of the molded gaskets 23 are electrically isolated. The electrical contacting of the two circuit boards 6, 7 takes place by means of not shown electrical lines to the contact plates 5. The two circuit boards 6, 7 with the three PTC elements 3 thereby constitute a heating unit 10. After arranging the two form seals 23 on the heating unit After forming the heating system 8 into the flat tubes 13 with the corrugated fins 12, a heating coil 9 or the heat exchanger 1 is present. Several heater 9 as shown in FIG Fig. 2 . 10 and 11 can also be connected to a heat exchanger 1 with a larger number of heating registers 9 to each other.

The net height H _{N of} the heat exchanger 1 as shown in FIG Fig. 3 is about 50 to 300 mm, preferably 100 to 200 mm and the mesh width B _N is about 50 to 300 mm, preferably 100 to 200 mm. The transverse division Q, ie the distance between the flat tubes 13 as shown in FIG Fig. 4 , is in this case between 5 and 30 mm, preferably 9 to 18 mm and the overall depth T _N as shown in FIG Fig. 8 is 6 to 50 mm, preferably 10 to 40 mm. The overall depth T _R is 10 to 50 mm, preferably 10 to 40 mm. The thickness D _{E of} the printed circuit boards 6, 7 is 0.2 to 1.5 mm, the thickness D _{1 of} the molded seals 23 0.1 to 1.5 mm and the width B _{R of} the tube 18 is 2 to 10 mm. The thickness D _{stone of} the PTC elements 3 is in the range between 0.8 to 3 mm.

Between the flat tubes 13 corrugated fins 12 are arranged as Wärmeleitelemente 11 ( Fig. 2 . 3 . 5 . 10 and 11 ). The corrugated fins 12 serve to enlarge the surface of the heat exchanger 1, in order to better release the heat emitted by the PTC elements 3 to the air, which flows through the heat exchanger 1. The flat tubes 13 also constitute heat-conducting elements 11. The heating composite 8, consisting of from the two circuit boards 6, 7, the PTC elements 3 and the molded seal 23, it is inserted before joining the pipe parts 39 of the flat tube 13 into the cavity 19 between the pipe parts 39. The relevant manufacturing steps are in the Fig. 12 to 14 shown. The corrugated fins 12 can be connected to the flat tube 13 or tube parts 39 either before or after the joining of the tube parts 39. The corrugated fins 12 can be connected to the flat tubes 13, for example, by gluing, welding or soldering. In addition, it is also possible to connect the corrugated fins 12 frictionally with the flat tubes 13, because a pressure force 33 is applied to a heat exchanger 1 with a plurality of flat tubes 13 or heating coils 9 and due to this pressure force 33 (FIG. 10 and 11 ), the corrugated fins 12 can be held between the flat tubes 13.

In the Fig. 12 to 14 are steps of the manufacturing process for producing the heating register 9 shown. In the in the Fig. 12 to 14 illustrated embodiment, the flat tube 13 consists of two tube parts 39. The two tube parts 39 are a first in cross-section substantially U-shaped half-shell 41 and a second substantially also U-shaped half-shell 42. At these two half-shells 41, 42 are already the Corrugated ribs 12, for example, attached by gluing or soldering. Between the two half shells 41 and 42 ( Fig. 12 ) forms before the merging and joining the two half-shells 41, 42 to the flat tube 13 of the cavity 19 from. In this cavity 19 of the heating composite 8 is introduced prior to the complete merging and joining of the two half-shells 41, 42. After introducing the heating composite 8 in the intermediate space 19 between the two half-shells 41, 42 ( Fig. 13 ), the two half-shells 41, 42 are completely pushed together with the application of a compressive force 33 to the corrugated fins 12 or the broad-side walls 20 of the flat tube 13 still to be produced ( Fig. 14 ). After completely merging the first and second half-shell 41, 42 are narrow side walls 21 as joints 38, which are each provided on a half-shell 41, 42, joined together, for example by gluing. In this case, during the joining of the narrow side walls 21 on the heating register 9, the pressure force 33 is applied ( Fig. 14 ), so that the heating composite 8 is held after the removal of the compressive force 33 under bias between the two broad side walls 20 of the flat tube 13. The heating system 8 is thus positively clamped between the two broad side walls 20 of the flat tube 13. In the 10 and 11 shown pressing force 33 on the heat exchanger 1 is thus a purely optional design, because due to the bias within a heating register 9 can be dispensed with the pressure force 33 after connecting the two pipe parts 39 to the flat tube 13. The pressing force 33 as shown in FIG 10 and 11 However, it may be necessary, provided that the corrugated fins 12 are fixed only under bias between the flat tubes 13 frictionally. In the 10 and 11 However, shown pressing force 33 can also be used in addition to a supplementary and additional tension of the heating system 8 in the flat tube 13.

In Fig. 15 is a further embodiment of the flat tube 13 is shown. The flat tube 13 is doing in an analogous manner to the illustration according to Fig. 12 to 14 connected to the heating system 8 to the heating coil 9. Here, the narrow side wall 21 of the half-shells 41, 42 correspondingly formed geometrically and is preferably at the support area between the first and second half-shell 41, 42 a not shown seal between the first and second half-shell 42 is arranged.

In Fig. 16 and 17 is an additional embodiment of the flat tube 13 shown. The flat tube 13 consists of a manufactured by deep drawing Tub 43 and a plate 44 each as pipe parts 39. At the tub 43 flanged lugs 46 are present. To produce the flat tube 13, the plate 44 is placed on the tub 43 and then the flanged tabs 46 are bent ( Fig. 17 ), so that the flanged tabs 46 attach the plate 44 to the tub 43. A positioning frame 45 serves to position the heating composite 8 within the cavity 19 enclosed by the flat tube 13. The production takes place analogously to the exemplary embodiment according to FIGS Fig. 12 to 14 , In Fig. 16 is shown by the heating system 8, only the molded seal 23. The molded seal 23 is a substantially rectangular shaped seal 23, which is placed on each of the first and second printed circuit board 6, 7 and the two printed circuit boards 6, 7 electrically insulated from the flat tube 13 from the tub 43 and the plate 44. The positioning frame 45 consists of an electrically insulating material such as the molded seal 23, for example made of plastic. The heat resistance of the plastic of the positioning frame 45 and the molded seal 23 is about 200 ° C. In the manufacture of a heat exchanger 1 with a plurality of heating registers 9, it is in the use of the flat tube 13 as shown in FIG Fig. 16 and 17 not necessary at the lower end of the flat tube 13, the second lower cover plate 15 to fix, because the flat tube 13 is already formed closed and fluid-tight at the lower end.

After attaching the Heizverbundes 8 in the flat tube 13 and the application of the compressive force 33 to the heat exchanger 1, an upper first cover plate 14 is applied to the upper ends of the flat tubes 13 and an optional second lower cover plate 15 on the lower, second ends of the flat tubes applied ( Fig. 5, 6 and 18 ). The first and second cover plate 14, 15 in this case has a plurality of substantially rectangular grooves into which the ends of the flat tubes 13 are inserted. In the grooves, a cutout 47 is present at the lower end of the grooves. In the cutout 47, for example, an adhesive is introduced as a seal 48. After insertion of the flat tubes 13 in the grooves of the first and second cover plate 14, 15, the ends of the flat tubes 13 are glued to this adhesive and thereby a liquid and dust-tight connection and sealing between the flat tubes 13 and the first and second cover plate 14, 15 produced. As a seal 48 may be used in addition to adhesive, for example, silicone. The first and second cover plate 14, 15 consists of metal or plastic. As a result, all the flat tubes 13 of the heat exchanger 1 are dust-tight and sealed against the environment of the heat exchanger 1. Thus, to the circuit boards 6, 7 or the PTC elements 3 within the cavity 19 no liquid and no dust penetrate.

An upper side of the first upper cover plate 14 is connected dust-tight and liquid-tight with the air conditioning housing 26, so that no dust and no liquid can penetrate into the cavity 19 at the upper ends of the flat tubes 13. Notwithstanding this, on the top of the first upper cover plate 14 also dust and liquid-tight an electronic housing can be attached (not shown).

The arranged within the channel 35 of the motor vehicle air conditioner 24 heat exchanger 1 is thus sealed dust and liquid-tight. Dust or liquid within the channel 35 can thus not penetrate into the cavity 19 within the flat tubes 13.

Overall, significant advantages are associated with the heat exchanger 1 according to the invention and the motor vehicle air conditioning system 24 according to the invention. The heating assembly 8 is arranged dust and liquid-tight within the flat tubes 13, so that in the air duct 35 existing dust particles or liquid can cause no damage to the heat exchanger 1. The molded seal 23 is a commercially available insulation film and can thus be made available inexpensively in the production.

LIST OF REFERENCE NUMBERS

1

Heat exchanger

2

Electric resistance heating element

3

PTC element

4

ladder

5

Electric contact plate

6

First circuit board

7

Second circuit board

8th

Heizverbund

9

heater

10

heating unit

11

thermally conductive element

12

corrugated fins

13

flat tube

14

First cover plate

15

Second cover plate

16

Walls of the pipe

17

cavity wall

18

pipe

19

cavity

20

Breitseitenwandung

21

narrow side

22

Electrical insulating element

23

shaped seal

24

Automotive air conditioning system

25

fan

26

Air conditioning case

27

bottom wall

28

housing

29

exit section

30

filter

31

Keltemittelverdampfer

32

White space within the flat tube

33

thrust

34

tube

35

channel

36

surface

37

tenter

38

joint

39

pipe part

40

clips

41

First half shell

42

Second half shell

43

tub

44

plate

45

positioning frame

46

Bördellasche

47

cutout

48

seal

H _N

net height

B _N

net width

Q

transverse pitch

T _N

overall depth

T _R

overall depth

D _E

Thickness of the printed circuit board

D _I

Thickness of the molded gasket

B _R

Width of the flat tube

D _stone

Thickness of the PTC stone

Claims (15)

Heat exchanger (1) comprising at least one electrical resistance heating element (2), in particular at least one PTC element (3), - At least two with the at least one electrical resistance heating element (2) electrically conductively connected conductor (4), in particular printed circuit boards (6, 7) to conduct electrical current through the at least one electrical resistance heating element (2) and thereby the electrical resistance heating element (2) to warm, at least one heat-conducting element (11) for transmitting heat from the at least one electrical resistance heating element (2) to a fluid to be heated, - At least one electrical insulating element (22), which electrically isolates the at least two conductors (4), preferably of the at least one heat conducting element (11), wherein - The at least two conductors (4) and / or the at least one electrical resistance heating element (2) in at least one of at least one cavity wall (17) limited cavity (19) are arranged and the at least one electrical insulating element (22) at least one molded seal (23 ), characterized in that
the at least one cavity wall (17) as at least one closed tube (18) with at least two joints (38) in cross section is formed and preferably the at least one tube (18) comprises at least two pipe parts (39). Heat exchanger according to claim 1, characterized in that the at least two joints (38) by means of a biasing force, for. B. by clips (40), and / or a flanging and / or bonding and / or welding and / or soldering of the at least two pipe parts (39) are formed. Heat exchanger according to claim 1 or 2, characterized in that the at least one tube (18) is formed by two U-shaped half-shells (41, 42) or the at least one tube (18) by a respective trough (43) and Plate (44) is formed. Heat exchanger according to one or more of the preceding claims, characterized in that the at least one tube (18) as at least one flat tube (13) is formed with two broad side walls (20) and two narrow side walls (21). Heat exchanger according to one or more of the preceding claims, characterized in that the at least one molded seal (23) between each one wall (16) of the at least one tube (18) and a conductor (4) is arranged, so that the at least two conductors ( 4) are electrically isolated with respect to the at least one tube (18). Heat exchanger according to one or more of the preceding claims, characterized in that in the cavity (19) has two, preferably substantially rectangular, shaped seals (23) are arranged
or
the at least one molded seal (23) in the cavity (19) as a hose (34), in particular shrink tube (34) is formed. Heat exchanger according to one or more of the preceding claims, characterized in that the at least one molded seal (23) is elastic and / or the at least one molded seal (23) consists at least partially of silicone or plastic or rubber and / or the at least one molded seal (23 ) is connected to the at least one tube (18) non-positively and / or positively and / or cohesively and / or the at least one molded seal (23) is a film. Heat exchanger according to one or more of the preceding claims, characterized in that the at least one molded seal (23) heat-transmitting or thermally conductive particles, for. For example, alumina and / or silicon carbide and / or boron nitride
and or
the at least one tube (18) from a first, z. B. upper, cover plate (14) at a first end, in particular fluid-tight, is closed
and or
the at least one tube (18) from a second, z. B. lower, cover plate (15) at a second end, in particular fluid-tight, is closed. Heat exchanger according to one or more of the preceding claims, characterized in that the at least one electrical resistance heating element (2), the at least two conductors (4) and the at least one molded seal (23) are connected to at least one heating compound (8), which or which within the at least a tube (18) is or are arranged and preferably a plurality of tubes (18) each with a heating compound (8) and between the tubes (18) arranged corrugated fins (12) form the heat exchanger (1), wherein, in particular by means of a tenter ( 37) or a spring, on the walls (16) of the at least one tube (18), in particular the Breitseitenwandungen (20) of the at least one flat tube (13), a compressive force is applied, so that due to the compressive force of the heating system (8) non-positively on the two walls (16), in particular broad side walls (20), fixed, in particular clamped, is. Motor vehicle air conditioning system (24), characterized in that the motor vehicle air conditioning system (24) comprises at least one heat exchanger (1) according to one or more of the preceding claims. Method for producing a heat exchanger (1) or an automotive air conditioning system (24), in particular a heat exchanger (1) according to one or more of claims 1 to 9 or an automotive air conditioning system (24) according to claim 10, comprising the steps: provide at least one electrical resistance heating element (2), in particular at least one PTC element (3), - Providing at least two electrical conductors (4), in particular circuit boards (6, 7), for passing electrical current through the at least one electrical resistance heating element (2), providing at least one heat conducting element (11) for transmitting heat from the at least one electrical resistance heating element (2) to a fluid to be heated, - Providing at least one electric Isollerelementes (22) as a molded seal (23) for electrically insulating the at least one Wärmeleitelements (11) of the at least two conductors (4), Connecting the at least two conductors (4) to the at least one electrical resistance heating element (2), thermally connecting the at least one heat-conducting element (11) to the at least one conductor (4) and / or to the at least one electrical resistance heating element (2), electrically insulating the at least two conductors (4), preferably from the at least one heat conducting element (11), by means of the at least one molded seal (23), by connecting the at least two conductors (4) to the at least one electrical resistance heating element (2) and the at least a form seal (23) are connected to at least one heating compound (8), - provide at least one tube (18), - wherein the at least one heat-conducting element (11) comprises at least one cavity wall (17) which encloses at least one cavity (19) and the at least one cavity wall (17) as a wall (16) of the at least one tube (18) is formed . characterized in that
the at least one tube (18) is made available from at least two tube parts (39) and the at least two tube parts (39) are connected to the at least one tube (18). A method according to claim 11, characterized in that the at least two pipe parts (39) by means of clips (40), soldering, gluing or welding, in particular fluid-tight, are connected. A method according to claim 11 or 12, characterized in that the at least one heating composite (8) is introduced into the at least one cavity (19) prior to joining the at least two pipe parts (39). Method according to one or more of claims 11 to 13, characterized in that after the introduction of the at least one heating composite (8) in the at least one cavity (19) on at least one wall (16) of the tube (18) a force is applied, so that the at least one heating compound (8) between two walls (16) of the at least one tube (18) is fixed non-positively and a direct contact between the two walls (16) and the molded seal (23) of the heating system (8) is produced. Method according to one or more of claims 11 to 14, characterized in that the at least one molded seal (23) is designed as a shrink tube (34) and the shrink tube (34) is shrunk onto the at least one heating compound (8) by the shrink tube (34) is heated.

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