EP1681906B1 - Sealed radiator - Google Patents

Description

The present invention relates to a radiator with a hollow body profile of metal and with a fixed in the hollow body by pressing heating element. In particular, the present invention relates to radiators that can be used in humid environments.

From the European patent EP 0 573 691 B1 a method for producing a PTC heating element is known in which an extruded profile has a base surface and a top surface and two narrow sides and the narrow sides are provided with outwardly curved portions which are so deformed during pressing in that on the one hand its radius of curvature is reduced and on the other hand its position is inclined outwards with respect to an axis of symmetry of the cross section. Such radiators have the advantage that they are simple and reproducible to produce and the heat transfer between the PTC element and the hollow body is optimally adjustable. In the known PTC radiators, the PTC element is encased in a tubular insulation film for electrical insulation and protection against environmental influences.

For various applications now increased moisture resistance of such profile heaters is required. For this purpose, the open ends must be closed with suitable sealants. In particular, especially the cable gland at one end of the profile must be sealed accordingly. A known solution is the casting of the two ends by means of various potting compounds, including silicone rubber, and is shown for example in connection with a braking resistor in DE 100 23 272 C1. Here, both housing ends are equally closed initially with a closure plate on which a Vergussmasseschicht is applied from an expanding putty, the volume increases with the curing. This is the aim of the dense closure of the braking resistor and a reduction of shrinkage cracks. An additional silicone resin layer serves to seal the potting compound layer.

However, this solution is very expensive to produce and therefore expensive. There is also the problem that due to imperfections, such as air bubbles, the desired tightness, z. B. according to IP 67, can not be achieved. The degree of protection IP 67 according to DIN 40050 (IEC 529, VDE 0470 or EN 60529), according to the first code regarding contact and foreign body protection, means that the component is protected against dust ingress, and according to the second code, which is the scope of protection Penetration of water indicates that sufficient protection is ensured during brief immersion. In DE 100 23 272 C1, for example, only a jet water protection, d. H. the degree of protection IP 65, reached.

In the context of tubular electric heating cartridges moisture-proof connections are known in which a connected to the connecting cables spout, inserted together with a ceramic disk in the open end of the heating cartridge and then the jacket is tapered by rolling or hammering to achieve a moisture-tight seal. Such a sealing device is known for example from the published patent application DE 1 690 679. A similar tubular sealed radiator is also known from DE 24 16 620 C3. The disadvantage of these solutions, however, is a relatively complex assembly technique, which is also due to the mechanical stresses for sensitive heating elements, such as PTC heating elements, not applicable.

U.S. Patent 4,822,980 discloses a heater adapted to be installed in the opening of the side wall of a compressor in which a PTC thermistor is disposed in an aluminum housing and sealed with a magnesium oxide filled silicone rubber. For supporting the wires and for visually covering the heating element caps are attached.

U.S. Patent 4,352,008 discloses an electric heater having a PTC heating element installed in an opening of a radiator and sealed by a thermally conductive material, preferably silicone rubber. However, there is nowhere in this heater provided a seal, but the silicone rubber is poured into the cavity.

Therefore, the object underlying the present invention, is to provide a generic radiator and an associated manufacturing method, whereby an improved protection against the ingress of foreign bodies and water can be achieved at the same time simple and inexpensive to manufacture.

This object is solved by the subject matter of the independent patent claims. Advantageous developments of the present invention are the subject of the dependent claims.

The present invention is based on the idea that a radiator, in which a prefabricated sealing element is provided, which is pressed together with a heating element by compressing the narrow sides of the hollow body profile in the hollow body, a seal at least up to a degree of protection according to DIN 40050 IP 67th , d. H. against dust entry and protection when immersed in water, guaranteed and yet does not preclude automated assembly. In particular, the manufacturing method according to the invention avoids additional work steps for sealing the radiator by the pressing of the seals occurs simultaneously with the pressing of the heating element. Furthermore, prefabricated sealing elements can be produced with substantially fewer defects than is possible with injected or cast potting compounds.

Depending on the field of application and the number of pieces to be produced, the hollow body profile can be produced by methods known per se, such as extrusion or milling. As a rule, a good heat-conducting metal, preferably aluminum, is used.

According to an advantageous development of the present invention, the heating element comprises a PTC heating element. A PTC heating element designates a resistance heating element which comprises at least one resistance component with a positive temperature coefficient (PTC component) and thus connects the functions of heating and temperature self-limiting in one element. In the smallest space can be achieved with such heating elements, which are usually made on a ceramic basis, high power densities. The PTC module is sandwiched for optimum heat dissipation between contact plates connected to the electrical terminals and the entire assembly is surrounded by electrical insulation.

Alternatively, however, the advantageous properties of the solution according to the invention can also be exploited in connection with resistance-wire heating elements.

In particular, when filling the hollow body with a suitable filler, such as magnesium oxide, can be carried out in an advantageous manner, the compression of the filling in one step with the pressing and sealing of the hollow body. The filler has several functions: First, it serves the electrical insulation between the heating element and the hollow body, on the other hand, it supports the heat transfer from the heating element to the hollow body and finally takes place in the filling material, a heat storage, which leads to a more uniform heat dissipation.

By forming the cross-section of the sealing element so that its outer contour substantially corresponds to the contour of the inner cross-section of the hollow body, a possible circumferential defect-free sealing can be achieved.

According to a preferred embodiment, the seal is made of a flexible material. In particular, silicone rubber as the material for the sealing element offers the advantages of easy manufacturability, sufficient elasticity and at the same time thermal stability.

According to an advantageous embodiment of the present invention, at least one opening is provided in the sealing element, through which the electrical connections are guided for contacting the heating element. In this way, on the one hand when using PTC heating elements prefabricated and already provided with electrical connections contact plates can be used on the heating element and inserted into the hollow body profile, on the other hand allows the fact that the terminals are circumferentially surrounded by the sealing material which is compressed during compression is, an optimal seal also the bushings of the electrical connections.

In addition, at least one electrically and thermally insulating protective hose can be provided, through which the connection cables are routed, on the one hand to form a kink protection and, on the other hand, to meet the requirements of electrical contact protection. Such protective tubes can be made, for example, from glass fiber, Kapton, PTFE or the like.

The inventive shaping of the hollow body profile is achieved in a simple manner that even with dimensional tolerances in the heating element and in the hollow body profile and tolerances in the movement of the punch only small deviations in the contact pressure arise and a permanent deformation is achieved, which leads to the desired tightness.

Figur 1

eine Draufsicht auf einen erfindungsgemäßen PTC-Heizkörper gemäß einer vorteilhaften Ausführungsform;

Figur 2

einen Schnitt durch den Heizkörper der Fig. 1 entlang der Schnittlinie B-B;

Figur 3

einen Schnitt durch den PTC-Heizkörper der Fig. 1 entlang der Schnittlinie A-A;

Figur 4

einen Längsschnitt durch den PTC-Heizkörper der Fig. 1 entlang der Schnittlinie C-C;

Figur 5

den Querschnitt B-B aus Fig. 1 vor und nach dem mechanischen Verpressen;

Figur 6

den Querschnitt A-A aus Fig. 1 vor und nach dem Verpressen;

Figur 7

einen Schnitt durch erfindungsgemäße Dichtung;

Figur 8

eine Draufsicht auf die erfindungsgemäße Dichtung;

Figur 9

ein Detail der erfindungsgemäßen Dichtung, wie in Fig. 7 mit dem Buchstaben X markiert;

Figur 10

einen Querschnitt durch einen Hohlkörper gemäß einer weiteren vorteilhaften Ausführungsform vor dem Verpressen;

Figur 11

einen Querschnitt durch einen Hohlkörper gemäß einer weiteren vorteilhaften Ausführungsform vor dem Verpressen;

Figur 12

einen Querschnitt durch einen Hohlkörper gemäß einer weiteren vorteilhaften Ausführungsform vor dem Verpressen;

Figur 13

einen Querschnitt durch einen Hohlkörper gemäß einer weiteren vorteilhaften Ausführungsform vor dem Verpressen;

Figur 14

einen Teil des Querschnitts durch den Hohlkörper gemäß der Figur 13 nach dem Verpressen;

Figur 15

einen Querschnitt durch einen Hohlkörper gemäß einer weiteren vorteilhaften Ausführungsform vor dem Verpressen;

Figur 16

einen Teil des Querschnitts durch den Hohlkörper gemäß der Figur 15 nach dem Verpressen;

Figur 17

einen Längsschnitt durch einen erfindungsgemäßen Heizkörper mit einem Widerstandsdraht-Heizelement;

Figur 18

einen Querschnitt durch den Heizkörper der Figur 17;

Figur 19

einen um 90° gedrehten Längsschnitt durch den Heizkörper der Figur 17.

Based on the embodiments shown in the accompanying drawings, the invention will be explained in more detail below. Similar or corresponding details are provided in the figures with the same reference numerals. Show it:

FIG. 1

a plan view of a PTC radiator according to the invention according to an advantageous embodiment;

FIG. 2

a section through the radiator of Figure 1 along the section line BB.

FIG. 3

a section through the PTC radiator of Figure 1 along the section line AA.

FIG. 4

a longitudinal section through the PTC radiator of Figure 1 along the section line CC ..;

FIG. 5

the cross section BB of Figure 1 before and after the mechanical pressing.

FIG. 6

the cross section AA of Figure 1 before and after the compression.

FIG. 7

a section through the seal of the invention;

FIG. 8

a plan view of the seal according to the invention;

FIG. 9

a detail of the seal according to the invention, as marked in Figure 7 with the letter X;

FIG. 10

a cross section through a hollow body according to a further advantageous embodiment prior to compression;

FIG. 11

a cross section through a hollow body according to a further advantageous embodiment prior to compression;

FIG. 12

a cross section through a hollow body according to a further advantageous embodiment prior to compression;

FIG. 13

a cross section through a hollow body according to a further advantageous embodiment prior to compression;

FIG. 14

a portion of the cross section through the hollow body according to the figure 13 after the pressing;

FIG. 15

a cross section through a hollow body according to a further advantageous embodiment prior to compression;

FIG. 16

a part of the cross section through the hollow body according to the figure 15 after the pressing;

FIG. 17

a longitudinal section through a radiator according to the invention with a resistance wire heating element;

FIG. 18

a cross section through the radiator of Figure 17;

FIG. 19

a 90 ° rotated longitudinal section through the radiator of Figure 17.

1 shows a top view of a heating element 100 according to an advantageous embodiment, in which a PTC heating element is used as the heating element 102. However, it is obvious to the person skilled in the art that the following statements can be analogously also applied to a radiator with a resistance wire heating element.

In this case, a PTC heating element 102 is accommodated in an aluminum hollow body profile 104. By way of example, a profile is shown as a hollow body profile in the embodiment shown, as it can be used for a control cabinet heating. Of course, the solution according to the invention can also be applied to profile shapes without ribs for heat dissipation, as required for example for kettles or baby food warmers. In particular, in the case of a use for heating liquids, the solution according to the invention is advantageous.

The PTC heating element 102 in this case comprises at least one PTC module 122, which is sandwiched by contact plates 124, and an optional insulating film 126 for establishing the required electrical insulation between the contact plates 124 and the hollow body profile 104. The contact plates 124 are connected to the electrical connections 106 connected.

For contacting the PTC heating element 102, two connecting leads 106 are provided, which are led out at the level of the cutting line A-A. According to the invention, the two open ends of the hollow body profile 104 are closed by means of two seals 108, 110. The two seals 108, 110 differ in their shape only in that the seal 108 is provided with openings 112 for passing through the terminals 106.

FIGS. 2 and 3 show the sections along the lines B-B and A-A from FIG. 1. It can be seen that the seals 108, 110 are adapted in their cross-section to the inner contour of the hollow body 104. The seal 108 attached to the terminal-side end of the heater body 100 also has two openings 112 for passing the lead wires 106. Of course, any other number of openings 106 could also be provided.

As already explained in connection with EP 0 573 691 B1, the hollow profile 104 has outwardly curved side surfaces 114 whose radius of curvature is reduced by the compression. By this particular embodiment is achieved that the cover and base surfaces 116, 118 can be optimally brought into contact with the PTC element. Thus, an optimal delivery of the heating energy to the outside.

4 shows a longitudinal section through the PTC heating body 100 according to the invention along the section line CC of FIG. 1. In the solution according to the invention shown in the step of pressing on the one hand the inner wall of the hollow body 104 is brought into contact with the PTC heating element over the entire area and made possible Thus, an optimal heat transfer, on the other hand, at the same time the gaskets 108, 110 are pressed so that the interior is sealed against ingress of dust and moisture up to a protection class of IP 67 or better.

The pressing operation will be explained in more detail with reference to FIGS. 5 and 6, which show sections along the section lines B-B and A-A of FIG. 1 before and after the pressing.

As can be seen from the left illustrations of the two figures, the outer contour of the seals 108, 110 fills the inner cross section of the hollow body profile 104 in the unpressed state. The height H of the profile opening in the unpressed state, for example, o, 15 mm greater than that of the seals. As a result, a simple installation of the seals is guaranteed. If, as symbolized by the arrows 120, mechanical pressure is exerted on the base and top surfaces of the hollow body profile 104, the radius of curvature of the outwardly curved region is reduced in the regions 114, so that the seals 108, 110 are compressed in this region, this reduces the height H to H '. Thus, the seal is firmly pressed in the area of the base and top surfaces and the diameter of the openings 112 have been reduced so much that even in the region of the connecting strands 106, a sufficient seal is achieved. Since, as can be seen in FIG. 4, the seals 108, 110 can escape in the longitudinal direction, a problem-free compensation of tolerances is possible.

The design of the prefabricated seal, which may for example consist of silicone, is apparent from FIGS. 7 to 9 in detail. In this case, the two seals 108 and 110 have the same cross-section and the seal 108 is additionally equipped with the openings 112 for passing through the connecting wires. As can be seen with reference to the detailed drawing X of FIG. 9, the outer contour of the seal 108, 110 is adapted in all details to the inner contour of the hollow body profile 104 and dimensioned so that it can be inserted with slight undersize in the unpressed profile , In the compressed state, the seal is compressed from all sides, so that sufficient pressure is exerted on the openings 112.

With reference to FIGS. 1 to 9, the manufacturing process of the PTC heater 100 according to the invention will be explained in detail below.

In the production of the PTC heating body 100 according to the invention, initially a PTC heating element 102, a hollow body profile 104 and the seals 108 and 110 are produced independently of one another. According to the invention, the outer contour of each sealing element substantially corresponds to the contour of the inner cross section of the hollow body 104. The hollow body 104 may be made of aluminum with magnesium and silicon admixtures, for example. As a sealing material is for example silicone in question, the z. B. was molded by means of an injection molding process. Possible alternative production methods are also punching or water jet cutting.

During assembly, the PTC element 102, which consists of at least one PTC module 122, the contact plates 124 provided with the electrical connections 106 and an insulating film 126, is first introduced into the hollow body 104. In this case, an additional insulating protective hose can be pulled around the connections 106. Shields and the like may be additionally provided.

In a next assembly step, the gaskets 108 and 110 are used. In this case, the seal 108 is inserted so that the terminals 106 are passed through the openings 112. Now, a pressing step is carried out analogously to the pressing of the PTC radiator, as shown in EP 0 573 691 B1. In this case, the regions 114 are deformed such that they have a reduced radius of curvature in their curved region and, moreover, are tilted by about 10 ° to 30 ° with respect to the vertical. As a result of this plastic deformation of the extruded profile 104, its inner cross section is reduced and the seal now abuts peripherally against the inner wall of the hollow body 104, while the openings 112 are deformed such that the connecting strands 106 are enclosed in a sealing manner.

As shown in EP 0 573 691 B1, the top surface and the base surface of the hollow body 104 with the PTC element 102 smoothly in abutment, whereby an optimal heat extraction from the PTC element to the hollow body 104 is ensured.

Of course, any differently shaped profiles can be sealed in the manner of the invention. In particular, it is not necessary that rib structures are provided for dissipating heat.

Various examples of differently shaped profiles of the hollow body 104, which have substantially the same inner cross section as the first embodiment shown in Figure 2, are shown in Figures 10 to 12. In particular, the design of the outer contours can be adapted to the respective heating task.

However, the inner cross section does not have to be limited to embodiments in which the side surfaces are curved convexly outwards and are deformed outwards during pressing.

FIG. 13 shows an example of a hollow body profile 104 before compression, in which the side surfaces 114 are concavely curved inward. When pressing arises the cross-sectional shape shown in Figure 14, in which the side surfaces 114 have deformed inwardly and the height has been reduced to H '.

Another example of a hollow body profile 104 with outwardly curved side surfaces 114 is shown in FIG. 15 before compression and in FIG. 16 after compression.

According to a further advantageous embodiment of the present invention may be used as a heating element 102 and a resistance wire heating element. FIGS. 17 to 19 show various sectional views of such a heating element 100 with a resistance wire heating element 102.

Analogously, the above with respect to the sealing elements 108, 110 also applies to this embodiment and corresponding elements are provided with the same reference numerals. However, in this embodiment, a filling with a filler 128, here magnesium oxide (MgO), additionally provided. The filler 128 has several functions: First, it serves the electrical insulation between the heating element 102 and the hollow body 104, on the other hand it supports the heat transfer from the heating element 102 to the hollow body 104 and finally takes place in the filling material 128, a heat storage in the Temporal means leads to a more uniform heat dissipation.

Claims (26)

1. Radiator having a metal hollow body profile (104) and a heating element (102) positioned in the hollow body (104), characterised in that the radiator (100) has at least one prefabricated sealing element (108, 110) for sealing the heating element (102) with respect to the environment and the at least one sealing element (108, 110) is squeezed into the hollow body (104).
2. Radiator according to claim 1, wherein the hollow body profile (104) is manufactured from aluminium.
3. Radiator according to claim 1 or 2, wherein the hollow body profile (104) is formed by an extruded profile.
4. Radiator according to at least one of the preceding claims, wherein the heating element (102) is a PTC heating element.
5. Radiator according to claim 4, wherein the PTC heating element (102) is fixed in the hollow body (104) by pressing.
6. Radiator according to claim 1 to 3, wherein the heating element (102) comprises a resistance wire heating element.
7. Radiator according to claim 6, wherein between the resistance wire heating element and the hollow body profile (104) a filling compound is provided.
8. Radiator according to claim 7, wherein the filling compound is manufactured from magnesium oxide.
9. Radiator according to at least one of the preceding claims, wherein the narrow sides of the hollow body profile (104) have regions which are bowed out convexly, their radius of curvature being reduced by the pressing.
10. Radiator according to at least one of the preceding claims, wherein the narrow sides of the hollow body profile (104) have regions which are bowed in concavely, their radius of curvature being reduced by the pressing.
11. Radiator according to at least one of the preceding claims, wherein the cross-section of the sealing element (108, 110) is so formed that its outer contour substantially corresponds to the contour of the inner cross-section of the hollow body (104).
12. Radiator according to at least one of the preceding claims, wherein the sealing element (108, 110) is manufactured from a flexible material.
13. Radiator according to claim 12, wherein the sealing element (108, 110) is manufactured from silicone.
14. Radiator according to at least one of the preceding claims, wherein the sealing element (108, 110) may be manufactured by the injection moulding technique, by punching, or by water jet cutting.
15. Radiator according to at least one of the preceding claims, wherein the sealing element (108, 110) has at least one aperture (112) for the passage of electrical terminals (106) for contacting of the heating element.
16. Radiator according to claim 15, wherein the terminals (106) are passed through at least one electrically and thermally insulating protective hose.
17. Method of manufacturing a radiator having a hollow body profile (104) composed of metal, a heating element (102) and at least one sealing element (108, 110) for sealing the heating element with respect to the environment, the method comprising the following steps:

    insertion of the heating element (102) into the hoiiow body (i 04),

    placing of the at least one sealing element (108, 110) in the hollow body,

    pressing of the hollow body in a direction transverse to a longitudinal axis of the hollow body.
18. Method according to claim 17, wherein the heating element (102) comprises a PTC heating element and the pressing is carried out until a base and upper face of the hollow body are in contact with an outer contour of the PTC heating element.
19. Method according to claim 18, wherein the heating element (102) comprises a resistance wire heating element and before the step of pressing, the following step is carried out:

    filling of the cavity between the heating element and the hollow body with a filling compound.
20. Method according to claim 19, wherein the filling compound is manufactured from magnesium oxide.
21. Method according to claim 18, wherein the PTC heating element is manufactured by the following steps:

    connection of the contact plates to electrically conductive terminals,

    embedding of a PTC component between the electrically conductive contact plates,

    encasing of the arrangement in an electrical insulator.
22. Method according to one of claims 17 to 21, wherein the step or placing the at least one sealing element (108, 110) in the hollow body (104) comprises:

    insertion of the sealing element in the hollow body, so that the outer contour of the cross-section of the sealing element substantially corresponds to the contour of the inner cross-section of the hollow body.
23. Method according to one of claims 17 to 22, wherein the step of placing the at least one sealing element (108, 110) in the hollow body (104) further comprises:

    passing of electrical terminals for contacting with the heating element through at least one aperture of the at least one sealing element.
24. Method according to one of claims 17 to 23, wherein the step of pressing comprises:

    deformation of convexly outwardly-bowed regions on the narrow sides of the hollow body in such a manner that their radius of curvature is reduced by the pressing;

    wherein the at least one seal has in its outer contour correspondingly convexly bowed regions, whose radius of curvature is correspondingly reduced by the deformation of the hollow body.
25. Method according to one of claims 17 to 25, wherein the step of pressing comprises:

    deformation of concavely inwardly-bowed regions on the narrow sides of the hollow body in such a manner that their radius of curvature is reduced by the pressing, wherein the at least one seal has in its outer contour corresponding concavely bowed regions, whose radius of curvature is correspondingly

    reduced by the deformation of the hollow body.
26. Method according to one of claims 17 to 25, wherein the hollow body profile (104) is manufactured from aluminium.

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