Electrical heating device

Abstract

Electrical heating device with a tube-shaped metal sleeve, with an insulating body that is arranged in the interior of the tube-shaped metal sleeve and is passed through by at least one tunnel-like opening, with an electrical heating element, that runs with at least one section in the tunnel-like opening and with a connecting wire for the direct or indirect electrical contacting and supply of the electrical heating element that also runs with at least one section in the tunnel-like opening, wherein the sections of the electrical heating element and of the connecting wire running in the tunnel-like opening overlap each other in a contact area (K) at least in some sections, wherein the contact area (K) is in an unheated section (u) of the electrical heating device.

Claims

1. An Electrical heating device with a tube-shaped metal sleeve, with an insulating body that is arranged in an interior of the tube-shaped metal sleeve and that is passed through by at least one tunnel-like opening, with an electrical heating element that runs with at least one section in the tunnel-like opening and with a connecting wire for indirect or direct electrical contacting and supply of the electrical heating element that similarly runs with at least one section in the tunnel-like opening, wherein sections of the electrical heating element and of the connecting wire running in the tunnel-like opening overlap each other in a contact area (K) at least in some sections, wherein the contact area (K) is in an unheated section (u) of the electrical heating device, wherein in the contact area (K), a window of the tunnel-like opening is provided in the insulating body, wherein the window allows access to the tunnel-like opening at a position of the window, especially from a radial direction.

2. The Electrical heating device according to claim 1, characterized in that the overlapping sections of the electrical heating element and of the connecting wire are connected to each other by resistive welding or ultrasonic welding.

3. The Electrical heating device according to claim 1, characterized in that at least one of the sections of the electrical heating element or of the connecting wire is flattened on a side facing the other of the at least one of the sections of the connecting wire or of the electrical heating element.

4. The Electrical heating device according to claim 3, characterized in that the electrical heating element and the connecting wire are made from a flat wire material.

5. The Electrical heating device according to claim 4, characterized in that, at least in some sections, the electrical heating element and the connecting wire are made from flat wire material and are arranged one above the other.

6. The Electrical heating device according to claim 5, characterized in that at least in some sections, the connecting wire includes first, second, third and fourth connecting wires made from flat wire material, the first and second connecting wires and the third and fourth connecting wires are arranged one above the other and are electrically contacted, respectively.

7. The Electrical heating device according to claim 5 characterized in that the connecting wire is comprised of connecting wires made from flat wire material arranged one above the other and are made from the same or from different materials.

8. The Electrical heating device according to claim 1, characterized in that the electrical heating element is U-shaped and legs of the U-shaped heating element are inserted into the at least one tunnel-like opening.

9. The Electrical heating device according to claim 1, characterized in that a cross section of the at least one tunnel-like opening deviates from a circular shape.

10. The Electrical heating device according to claim 1, wherein the connecting wire includes first and second connecting wires, the first and second connecting wires are connected to a first leg of the electrical heating element, the electrical heating element having a U-shape.

11. The Electrical heating device according to claim 1, characterized in that the contact area (K) is embedded or preferably compacted into a ceramic insulating compound or magnesium oxide.

12. The Electrical heating device according to claim 1, characterized in that the heating element and the connecting wire are not coiled but instead straight.

13. The Electrical heating device according to claim 1, wherein the electrical heating element includes a first leg with a first end and a first top face, the connecting wire including first and second connecting wires, the first connecting wire positioned in facing engagement with the first end and the first leg being substantially coaxial with the first connecting wire, the second connecting wire overlapping the first leg and the first connecting wire adjacent the first top face.

14. The Electrical heating device according to claim 13, wherein the first connecting wire is connected to the second connecting wire by a first weld and the second connecting wire is connected to the first leg by a second weld.

15. The Electrical heating device according to claim 13, wherein the electrical heating element has a U-shape with an arc-shaped end section and a second leg, the first and second legs spaced from the arc-shaped end section, the connecting wire including a third connecting wire and a fourth connecting wire, the third and fourth connecting wires connected to the second leg.

16. The Electrical heating device according to claim 1, wherein the electrical heating element has a U-shape with a first leg and a second leg, the connecting wire including first and second connecting wires connected to the first leg.

17. The Electrical heating device according to claim 16, wherein the connecting wire includes a third connecting wire and a fourth connecting wire, the third and fourth connecting wires connected to the second leg.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

(2) In the drawings:

(3) FIG. 1a: a first embodiment for an electrical heating device,

(4) FIG. 1b: a first enlarged detail of a section in the image plane through the embodiment from FIG. 1a,

(5) FIG. 1c: a second enlarged detail of a section in the image plane through the embodiment from FIG. 1a,

(6) FIG. 1d: the electrical heating device from FIG. 1a in one possible use configuration,

(7) FIG. 1e: a cross section through a contact area of the electrical heating device from FIG. 1a in the direction perpendicular to its running direction,

(8) FIG. 2a: a second embodiment for an electrical heating device,

(9) FIG. 2b: a first enlarged detail of a cross-section in the image plane through the embodiment from FIG. 2a,

(10) FIG. 2c: a second enlarged detail of a cross-section in the image plane through the embodiment from FIG. 2a,

(11) FIG. 2d: is a perspective view of the arrangement of electrical heating element and connecting wires of the electrical heating device from FIG. 2a,

(12) FIG. 2e: is a perspective view of a variant of the arrangement from FIG. 2d;

(13) FIG. 3a: a cross section through a first example for an insulating body of an electrical heating device,

(14) FIG. 3b: a cross section through a second example for an insulating body of an electrical heating device,

(15) FIG. 3c: a cross section through a third example for an insulating body of an electrical heating device,

(16) FIG. 3d: a cross section through a fourth example for an insulating body of an electrical heating device according to the invention,

(17) FIG. 3e: a cross section through a fifth example for an insulating body of an electrical heating device according to the invention,

(18) FIG. 4a: is a perspective view of a first example for a contact area between the electrical heating element and connecting wire,

(19) FIG. 4b: is a perspective view of a second example for a contact area between the electrical heating element and connecting wire,

(20) FIG. 4c: is a perspective view of a third example for a contact area between the electrical heating element and connecting wire,

(21) FIG. 4d: is a perspective view of a fourth example for a contact area between the electrical heating element and connecting wire, and

(22) FIG. 4e: is a perspective view of a fifth example for a contact area between the electrical heating element and connecting wire.

DETAILED DESCRIPTION OF THE INVENTION

(23) FIG. 1a shows an embodiment for an electrical heating device 100 in the form of a coiled tube cartridge, which, as shown in FIG. 1d, can be bent and/or coiled, e.g., into a desired shape for an application and has an unheated area that is marked with u in all figures in which it is visible, and also with two-sided connections 110, 111. As can be seen especially in the section view of FIG. 1b, the electrical heating device 100 has a tube-shaped metal sleeve 120, in whose interior an insulating body 130 is arranged that is passed through by a tunnel-like opening 140.

(24) Within the tunnel-like opening 140 there is an electrical heating element 141 that overlaps, at its end shown in FIG. 1b and at its other end that can be arranged, for example, at the same distance from the connection 111 as the end shown in FIG. 1b from the connection 110, in a contact area K with one section of a connecting wire 145 and is connected to this wire, for example, welded. Here, in the contact area K, at least one of the connected conductors, that is, the electrical heating element 141 and/or the connecting wire 145, is flattened, as can be seen particularly well in the cross-sectional view of FIG. 1e.

(25) Other possible constructions of the cross sections of the electrical heating element 141 and connecting wire 145 can be seen, for example, in FIGS. 3a to 3e, where connecting wires 315, 316, 325, 326, 335, 336, 345, 346, 355, 356 and heating elements 311, 312, 321, 322, 331, 332, 341, 342, 351, 352 arranged in insulating bodies 310, 320, 330, 340, 350 each with two tunnel-like openings 317, 318, 327, 328, 337, 338, 347, 348, 357, 358 are shown.

(26) The empty volumes remaining in the tunnel-like opening 140 can be filled with insulating material, e.g., MgO powder.

(27) As an example, in the insulating body 130 in the contact area K, two opposing windows 131, 132 are shown. If such windows are present, it is possible to produce at least one of the electrical contacts between electrical heating element 141 and connecting wire 145 only after inserting these components from different sides into the tunnel-like opening 140, even if this is not to be a press-fit contact, bust instead should be a welded, soldered, or crimped connection.

(28) As shown in FIG. 1c, a supply line 190 is led with electrical conductor 191 into the interior of the connection 110 filled with magnesium oxide 192. The electrical conductor 191 is then connected to the connecting wire 145 with a crimping element 193.

(29) The contact area and the connection 111 are built analogously on the right side of the electrical heating device 100 shown in FIGS. 1a to 1e.

(30) FIGS. 2a to 2e show a second embodiment of an electrical heating device 200, with tube-like metal sleeve 220 with base 221, insulating body 230 arranged in the interior of the tube-like metal sleeve 220 with these tunnel-like openings 240, 260 passing from one end side to the other end side, a U-shaped electrical heating element 241 and connecting wires 245a, 245b, 246a, 246b in which there is a connection 210 to a supply line 290 only on one side.

(31) As can be seen especially well in the diagrams 2d and the variant of the diagram 2e, which differ only by the shape of the arc-shaped end section 241a, 241b of the electrical heating element, in this embodiment both the electrical heating element 241 and also the connecting wires 245a, 245b, 246a, 246b are each made from a flat wire material, whose cross section is constant. Here, the electrical heating element 241 is preferably made from a heating conductor material, e.g., a nickel-copper alloy, a nickel-chromium alloy, or a suitable ternary alloy, while the connecting wires 245a, 245b, 246a, 246b are preferably made from materials with good electrical conductivity properties, e.g., Cu or Ni, in order to reduce the power output in the area of the connecting wires 245a, 245b, 246a, 246b.

(32) As can be seen especially well in FIGS. 2d and 2e, the two connecting wires 245a, 245b and 246a, 246b are respectively connected to an end section of the heating element 241, of which the connecting wires 245a and 246a respectively contact the heating element 241 on the end side and the other connecting wires 245b and 246b overlaps the heating element 241 in the contact area K. This arrangement makes it especially simple to produce a defined contact with good electrical conductivity properties.

(33) It can also be seen, especially in connection with FIG. 2c, that in one section in the interior of the tube-like metal sleeve 220, two connecting wires 245a, 245b and 246a, 246b run parallel to each other and in electrical contact with each other, in order to form an unheated zone, in which the cross section is increased and thus the drop in heating power is low.

(34) In FIGS. 3a and 3b, arrangements of heating elements 311, 312, 321, 322 and connecting wires 315, 316, 325, 326 overlapping the heating elements 311, 312, 321, 322 in some sections in the tunnel-like openings 317, 318, 327, 328 of insulating bodies 310, 320 are shown. While this can guarantee a good linear contact, there is still a certain problem for reliable and safe processing, which results from the fact that two round conductor sections of heating elements 311, 312, 321, 322 and connecting wires 315, 316, 325, 326 must be positioned in a circular hole and an electrical contact must be produced between them, because slippage of the relative position of the conductor sections is easily possible. In addition, the interior 313, 314, 323, 324 of the tunnel-like openings 317, 318, 327, 328 is not used optimally.

(35) These problems are avoided in the embodiments of FIGS. 3c to 3e, where similar connecting wires 335, 336, 345, 346, 355, 356 and heating elements 331, 332, 341, 342, 351, 352 arranged in insulating bodies 330, 340, 350 each with two tunnel-like openings 337, 338, 347, 348, 357, 358 in the cross section through a contact area K are shown.

(36) Therefore, because in the contact area at least one of the conductors, that is, a connecting wire 335, 336, 345, 346, 355, 356 and/or a heating element 331, 332, 341, 342, 351, 352 is flattened on its side facing the conductor, with which the contact is created, that is, the heating element 331, 332, 341, 342, 351, 352 or the connecting wire 335, 336, 345, 346, 355, 356, the positioning and accordingly also the subsequent contacting is much more precise and better reproducible. In addition, by adapting the cross section of the tunnel-like openings 337, 338, 347, 348, 357, 358, on one hand, these can be better used, and, on the other hand, the insertion position can be defined exactly.

(37) As shown in FIGS. 4a to 4e, the contact area between the electrical heating elements 411, 421, 431, 441, 451 made from a heating conductor material and connecting wires 415, 425, 426, 435, 445, 446, 455, 456, 457 with good electrical conductivity properties can have different constructions. The simplest option associated with the lowest consumption of material is shown in FIG. 4a, in which an overlap of flattened sections of electrical heating element 411 and connecting wire 415 is easily produced. In contrast to the other embodiments of FIGS. 4b to 4d, however, here it can still occur that there is no flat contact due to tilting during insertion.

(38) This can be avoided in that a second connecting wire 426, 446 preferably adapted with respect to its cross section to the cross section of the electrical heating element 421, 441 is used, which is brought into end-side contact with the electrical heating element 421, 441. The variant shown in FIG. 4b leads to unheated sections of the electrical heating device that come especially close to the ideal but is associated with higher consumption of materials than the variant of FIG. 4d. Another option consists in continuing the heating element 431 also in the unheated area u, but there in electrical contact with the connecting wire 435 with good electrical conductivity properties.

(39) If an even larger cross section is needed in the unheated area u, there is also the possibility, as shown in FIG. 4e, to provide, in addition to a connecting wire 456 that is adapted with respect to its cross section to the cross section of the electrical heating element 451 and that is brought into end-side contact with the electrical heating element 451 and that is selectively made from the material of the electrical heating element 451 or from a material with good electrical conductivity properties, such as, e.g., copper, also additional connecting wires 455, 457 that are arranged above and below, overlapping the electrical heating element 451 and the connecting wire 456 and made from a material with good electrical conductivity properties.

(40) It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

(41) TABLE-US-00001 List of reference symbols 100, 200 Electrical heating device 110, 111, 210 Connection 120, 220 Tube-shaped metal sleeve 130, 230, 310, 320, 330, Insulating body 340, 350 131, 132 Window 140, 240, 260, 317, 318, 327, 328 Tunnel-like opening 337, 338, 347, 348, 357, 358 141, 241, 311, 321, 331, 341, Electrical heating element 351, 411, 421, 431, 441, 451 145, 245a, 245b, 246a, 246b, 315, Connecting wire 316, 325, 326, 335, 336, 345, 346, 355, 356, 415, 425, 426, 435, 445, 446, 455, 456, 457 190, 290 Supply line 191 Electrical conductor 192 Magnesium oxide 193 Crimped element 221 Base K Contact area u Unheated area A, B Detail