Heating Assembly

Abstract

A heating assembly for a thermal joining device, the heating assembly including a base body, through which a fluid passage passes and which is provided on an external surface with a heating device having a ceramic substrate designed as a thick-film ceramic material and a metallic heating conductor, wherein the heating conductor is produced from an anti-adhesion alloy, and/or wherein the heating conductor is coated with an anti-adhesion alloy coating, the anti-adhesion alloy containing a proportion of at least 5 percent by weight of at least one element from the group of the metals of the rare earths.

Claims

1. A heating assembly for a thermal joining device, the assembly comprising a base body, through which a fluid passage passes and which is provided on an external surface with a heating device comprising a ceramic substrate designed as a thick-film ceramic material and a metallic heating conductor, wherein the heating conductor is produced from an anti-adhesion alloy, and/or wherein the heating conductor is coated with an anti-adhesion alloy coating, the anti-adhesion alloy containing a proportion of at least 5 percent by weight of at least one element from the group of the metals of the rare earths.

2. The heating assembly according to claim 1, wherein the heating conductor is applied to the ceramic substrate as an amorphous mass, and joined to the substrate by adhesive force.

3. The heating assembly according to claim 2, wherein the heating conductor is applied to the ceramic substrate in a spraying or screen printing process or in a direct printing process.

4. The heating assembly according to claim 2, wherein the heating conductor is joined to the substrate involving thermal effects,

5. The heating assembly according to claim 1, wherein the heating conductor is produced from a strip material.

6. The heating assembly according to claim 1, wherein an intermediate layer is placed between the substrate and the heating conductor for the improvement of an adhesive joint between the substrate and the heating conductor.

7. The heating assembly according to claim 6, wherein the intermediate layer is electrically insulating.

8. The heating assembly according to claim 6, wherein the intermediate layer is a layer of a ceramic compound with proportions of at least one oxide or carbide or nitride or fluoride or boride or silicate of a metal of the rare earths.

9. The heating assembly according to claim 1, wherein an intermediate layer is placed between the heating conductor and an anti-adhesion alloy coating for the improvement of an adhesive joint between the heating conductor and the anti-adhesion alloy.

10. The heating assembly according to claim 9, wherein the intermediate layer is electrically insulating.

11. The heating assembly according to claim 9, wherein the intermediate layer is a layer of a ceramic compound with proportions of at least one oxide or carbide or nitride or fluoride or boride or silicate of a metal of the rare earths.

12. The heating assembly according to claim 1, wherein the coating applied to the heating conductor is formed as an electrically insulating layer from an anti-adhesion alloy.

13. The heating assembly according to claim 1, wherein the anti-adhesion alloy coating applied to the heating conductor is produced by spraying or sputtering or printing or dipping.

14. The heating assembly according to claim 1, wherein the heating conductor is produced from a first anti-adhesion alloy having a first part by weight of at least one element from the group of the metals of the rare earths, and wherein the heating conductor is coated with a coating of a second anti-adhesion alloy having a second part by weight of at least one element from the group of the metals of the rare earths, the first part by weight being less than the second part by weight.

15. The heating assembly according to claim 1, wherein a layer thickness of an anti-adhesion alloy coating applied to the heating conductor is less than 500 micrometers.

16. The heating assembly according to claim 15, wherein the layer thickness of the anti-adhesion alloy coating is less than 100 micrometers.

17. The heating assembly according to claim 15, wherein the layer thickness of the anti-adhesion alloy coating is less than 40 micrometers.

18. The heating assembly according to claim 15, wherein the layer thickness of the anti-adhesion alloy coating is less than 20 micrometers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Advantageous embodiments of the invention are illustrated in the drawing, of which:

[0020] FIG. 1 shows a first embodiment of a heating assembly on which a coating of an anti-adhesion alloy is formed,

[0021] FIG. 2 shows a second embodiment of a heating assembly in which the heating conductor and a coating applied thereto are formed from an anti-adhesion alloy,

[0022] FIG. 3 shows a further embodiment of a heating assembly in which the heating conductor and the coating are formed from an anti-adhesion alloy and an intermediate layer is formed between the heating conductor and the substrate,

[0023] FIG. 4 shows a further embodiment of a heating assembly in which a coating of a heating conductor is produced from an anti-adhesion alloy and the heating conductor is applied to an intermediate layer opposite the substrate,

[0024] FIG. 5 shows a further embodiment of a heating assembly in which a coating on the heating conductor is produced from an anti-adhesion alloy and the heating conductor is applied to an intermediate layer opposite the ceramic substrate,

[0025] FIG. 6 shows a further embodiment of a heating assembly in which the heating conductor and a coating applied to the heating conductor are produced from an anti-adhesion alloy and an intermediate layer each is formed between the heating conductor and the applied coating and the ceramic substrate, and

[0026] FIG. 7 is a side view of a heating assembly.

DETAILED DESCRIPTION

[0027] In the following description of the various embodiments of the invention, reference numbers varying by the amount of twenty are used for components of identical function.

[0028] A first embodiment of a heating assembly 1 shown in FIG. 1 is provided for use in a joining machine not shown in the drawing, in particular in a welding machine for plastic film. The heating assembly 1 comprises a profiled base body 2, which is designed as a rectangular tube purely by way of example. In its interior, the base body 2 has a fluid passage 3, through which a coolant, preferably a cooling liquid, in particular water, can flow if the heating assembly 1 is used in a joining machine not shown in the drawing. By way of example, it is provided that the base body 2 is made of a metallic material, in particular aluminium or stainless steel, and that the ceramic substrate 6 is applied to the outer surface 4 of the base body 2 using a thick film method. The substrate 6 is in particular used for the electric insulation and the thermal coupling of the heating conductor 7 located on a substrate surface 8 of the ceramic substrate 6 against the base body 2.

[0029] Purely by way of example, it is provided that the heating conductor 7 has a rectangular cross-section extending in a strip shape along the base body 2. In the embodiment according to FIG. 1, the heating conductor 7 is produced from an amorphous mass with a proportion of metal, in particular silver, which is joined to the ceramic substrate 6 by adhesive force in a suitable manner. In order to avoid an adhesion of a workpiece not shown in the drawing, in particular a plastic film, to the heating conductor 7, which comes into direct contact with the workpiece during a joining operation, a coating 9 is provided, which covers both the heating conductor 7 and the rest of the substrate surface 8 not covered by the heating conductor 7, and which is designed as an anti-adhesion alloy.

[0030] The coating designed as an anti-adhesion alloy preferably comprises a proportion of at least 5 percent by weight of at least one element from the group of the metals of the rare earths and is in particular represented by an oxide or carbide or nitride or fluoride or boride or silicate. The coating 9, which, like the heating conductor 7 and the ceramic substrate 6, is not shown true to scale, can be applied by spraying, sputtering, screen printing or dipping, for example.

[0031] In the illustrated embodiment, it is provided that the ceramic substrate has a layer thickness in the range of less than 0.1 millimetres, the heating conductor has a thickness of less than 0.07 millimetres and the coating 9 has a thickness of less than 0.04 millimetres.

[0032] The second embodiment of a heating assembly 21 shown in FIG. 2 differs from the heating assembly 1 according to FIG. 1 in that the heating conductor 27 is produced from an anti-adhesion alloy with a proportion of at least 5 percent by weight of at least one element from the group of the metals of the rare earths. The heating conductor 27 can optionally be applied to the associated ceramic substrate 26 as an amorphous mass or joined to the ceramic substrate 26 in the form of a strip material by adhesive force.

[0033] In the third embodiment of a heating assembly 41 shown in FIG. 3, both the heating conductor 47 and the coating 49 are formed from an anti-adhesion alloy like in the second embodiment of the heating assembly 21 shown in FIG. 2. In addition, an intermediate layer 50 is provided between the ceramic substrate 46 and the heating conductor 47, the intermediate layer 50 being preferably electrically insulating and in particular a layer of a ceramic compound with proportions of at least one oxide or carbide or nitride or fluoride or boride or silicate of a metal of the rare earths. The intermediate layer 50 is likewise not shown true to scale and provides an advantageous adhesive coupling between the heating conductor 47 and the ceramic substrate 46.

[0034] The fourth embodiment of a heating assembly 61 shown in FIG. 4 differs from the heating assembly according to FIG. 3 in that the heating conductor 67 is produced from a metallic material commonly used for such heating conductors, for example from a stainless steel alloy. In this embodiment, there is likewise provided an intermediate layer 70 between the heating conductor 67 and the ceramic substrate 66, and the anti-adhesion alloy coating 69 is joined to the intermediate layer 70 by adhesive force in some areas.

[0035] The fifth embodiment of a heating assembly 81 shown in FIG. 5 is a variant of the first embodiment of a heating assembly 1 as shown in FIG. 1, wherein an intermediate layer 90 is provided between the heating conductor 87 made of a metallic material, for example stainless steel, and the ceramic substrate 86. This intermediate layer 90 can in particular be represented by an electrically insulating alloy, in the illustrated embodiment by a layer of a ceramic compound with proportions of at least one oxide or carbide or nitride or fluoride or boride or silicate of a metal of the rare earths. The intermediate layer 90 is used to improve the adhesive joint between the heating conductor 87, which is produced from a conventional material such as copper or silver with a proportion of glass, in particular from an amorphous mass, and the coating 89, which is produced from an anti-adhesion alloy. This applies in the same way to the intermediate layer 91 between the heating conductor 87 and the coating 89 represented by an anti-adhesion alloy.

[0036] The sixth embodiment of a heating assembly 101 shown in FIG. 6 is a variant of the third embodiment of a heating assembly 41 as shown in FIG. 3, in which, in addition to the intermediate layer 110 between the heating conductor 107 and the ceramic substrate 106, a further intermediate layer 111 is provided between the heating conductor 107 and the coating 109 represented by an anti-adhesion alloy.

[0037] FIG. 7 is, purely by way of example, a side view of the heating assembly 1 according to FIG. 1. End connectors 12 for supplying and discharging a coolant to and from the fluid passage 3, which is indicated by broken lines only, are fitted to the base body 2, which is designed as a rectangular tube in the illustrated embodiment.