Electric cartridge type heater and method for manufacturing same

Abstract

An electric cartridge type heater (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000) has at least one the tubular metallic jacket (101, 201, 301, 401, 501, 601, 701, 801, 901, 1001), at least one electric resistance wire (102, 202, 302, 402, 502, 602, 702, 802, 902, 1002) arranged in the interior space of the tubular metallic jacket with two ends for electrically contacting the electric resistance wire, wherein the at least one electric resistance wire is electrically isolated from the tubular metallic jacket by an electrically insulating material (103, 203, 303, 403, 503, 603, 703, 903) arranged in the interior space of the tubular metallic jacket (101, 201, 301, 401, 501, 601, 701, 801, 901, 1001). The electric resistance wire is self-supporting. A method is also provided for manufacturing such an electric cartridge type heater.

Claims

1. An electric cartridge type heater comprising: a tubular metallic jacket; a self-supported resistance wire arranged in an interior of the tubular metallic jacket and having contact ends electrically contacting the resistance wire, the self-supported resistance wire comprising a resistance wire configuration, said resistance wire configuration being maintained via the self-supported resistance wire without additional mechanical stress provided from any other components of the electric cartridge type heater; and an electrically insulating material arranged in the interior of the tubular metallic jacket, wherein the resistance wire is electrically insulated from the first tubular metallic jacket by the electrically insulating material.

2. An electric cartridge type heater in accordance with claim 1, further comprising a positioning element provided in the interior of the tubular metallic jacket for a defined fixation of a position of the resistance wire, wherein the resistance wire generates heat when an electrical current passes through the resistance wire, wherein the resistance wire configuration is maintained during removal of the self-supported resistance wire from an interior of the tubular metallic jacket.

3. An electric cartridge type heater in accordance with claim 1, further comprising another tubular metallic jacket arranged concentrically to the tubular metallic jacket in the interior space thereof, so that the self-supporting resistance wire is arranged between the tubular metallic jacket and the another tubular metallic jacket.

4. An electric cartridge type heater in accordance with claim 3, wherein the another tubular metallic jacket has an interior space.

5. An electric cartridge type heater in accordance with claim 3, further comprising additional electrically insulating material having a thermal conductivity that is lower than that of the electrically insulating material between the self-supporting resistance wire and the another tubular metallic jacket, the additional electrically insulating material being arranged between the tubular metallic jacket and the self-supporting resistance wire.

6. An electric cartridge type heater in accordance with claim 1, further comprising a spacer which makes it possible to arrange the resistance wire reproducibly in the tubular metallic jacket.

7. An electric cartridge type heater in accordance with claim 1, wherein the resistance wire has a section leading away from a connection-side end face of the electric cartridge type heater and another section connected with the section in an electrically conducting manner and leading back to the connection-side end face, wherein the section and the another section of the resistance wire are designed such that they are coiled one around the other.

8. An electric cartridge type heater in accordance with claim 1, wherein the resistance wire extends in a coiled form and contact ends, electrically contacting the resistance wire, or a section of an electric connection means extend in the space enclosed by the coils to a connection-side end face of the electric cartridge type heater.

9. An electric cartridge type heater in accordance with claim 1, wherein a pitch of the resistance wire in the area formed with a smallest pitch corresponds at most to 3 times a diameter of the resistance wire.

10. An electric cartridge type heater in accordance with claim 1, wherein the self-supporting resistance wire extends in a meandering pattern.

11. An electric cartridge type heater in accordance with claim 1, wherein the contact ends electrically contacting the resistance wire point in the same direction.

12. An electric cartridge type heater in accordance with claim 1, wherein the electric cartridge type heater is compacted by a reduction of a cross section.

13. An electric cartridge type heater in accordance with claim 1, wherein a cross section of the self-supporting resistance wire has a shorter extension in a radial direction than in an axial direction.

14. An electric cartridge type heater in accordance with claim 1, further comprising: another tubular metallic jacket, the another tubular metallic jacket being arranged concentrically to the tubular metallic jacket, within the three-dimensional curve defined by the self-supporting resistance wire, so that the another metallic jacket is surrounded by at least one section of the self-supporting resistance wire when viewed in any radial direction of the another metallic jacket, wherein an arrangement comprising at least the tubular metallic jacket, the another tubular metallic jacket and the self-supporting resistance wire is arranged on a contoured mandrel and pressed radially, so that at least the diameter of the interior space of the another tubular metallic jacket varies over the extension thereof.

15. A method for manufacturing an electric cartridge type heater, the method comprising the steps of: providing a tubular metallic jacket; deforming a self-supporting resistance wire, so that the resistance wire describes a preset curve in space, which curve is arranged in an interior space of the tubular metallic jacket, in a fixed position; arranging the deformed self-supporting resistance wire in the interior space of the tubular metallic jacket, wherein a shape of the deformed self-supporting resistance wire is maintained with no mechanical stress provided by any further components of the electric cartridge type heater; and embedding the deformed self-supporting resistance wire in an electrically insulating material, so that an electric contact is prevented between sections of the preset curve in space, which curve is described by the deformed self-supporting resistance wire, and a remainder of the deformed self-supporting resistance wire and the tubular metallic jacket, wherein the shape of the deformed self-supporting resistance does not change when the deformed self-supporting resistance wire is inserted in the interior space of the tubular metallic jacket.

16. A method in accordance with claim 15, wherein the self-supporting resistance wire is coiled on a mandrel to deform the self-supporting resistance wire such that the self-support resistance wire comprises a plurality of coils, wherein a distance between each coil and an adjacent coil is maintained by the deformed self-supporting resistance wire without any mechanical stress from any further components of the electric cartridge type heater.

17. A method in accordance with claim 15, wherein a cross section of the self-supporting resistance wire is changed by pressing to reduce directions that correspond to a radial direction of the metallic jacket, after inserting the self-supporting heat resistance wire into the tubular metallic jacket, and after the deformation of the self-supporting resistance wire into the preset curve and before the deformed self-supporting resistance wire is arranged in the interior space of the tubular metallic jacket, wherein the resistance wire generates heat when an electrical current passes through the resistance wire.

18. A method in accordance with claim 15, wherein further comprising: providing another tubular metallic jacket; arranging the another tubular metallic jacket concentrically to the tubular metallic jacket further, within the three-dimensional curve described by the self-supporting resistance wire, so that the another metallic jacket is surrounded by at least one section of the self-supporting resistance wire when viewed in any radial direction of the another metallic jacket.

19. A method in accordance with claim 18, wherein an arrangement comprising at least the tubular metallic jacket, the another tubular metallic jacket and the self-supporting resistance wire is arranged on a contoured mandrel and pressed radially, so that at least the diameter of the interior space of the another tubular metallic jacket varies over the extension thereof.

20. An electric cartridge type heater comprising: a tubular metallic jacket; a self-supported resistance wire arranged in an interior of the tubular metallic jacket and having contact ends electrically contacting the resistance wire, the resistance wire comprising a plurality of coils, wherein a shape of the resistance wire and a distance between each of the coils are maintained exclusively via an internal stress of the resistance wire, whereby the shape of the resistance wire and the distance between each of the coils are maintained without additional supporting elements and a mechanical tension; and an electrically insulating material arranged in the interior of the tubular metallic jacket, wherein the resistance wire is electrically insulated from the tubular metallic jacket by the electrically insulating material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1a is sectional view showing a first exemplary embodiment of an electric cartridge type heater with the metallic jacket cut open and with the electrically insulating material partially removed;

(2) FIG. 1b is a perspective view showing a resistance wire assembly unit of the exemplary embodiment from FIG. 1a;

(3) FIG. 1c is a perspective view showing a variant of the resistance wire assembly unit, which can be used in the exemplary embodiment from FIG. 1a;

(4) FIG. 2a is sectional view showing a second exemplary embodiment of an electric cartridge type heater with the metallic jacket cut open and with the electrically insulating material partially removed;

(5) FIG. 2b is a perspective view showing the resistance wire assembly unit of the exemplary embodiment from FIG. 2a;

(6) FIG. 3a is sectional view showing a third exemplary embodiment of an electric cartridge type heater with the metallic jacket cut open and with the electrically insulating material partially removed;

(7) FIG. 3b is a perspective view showing the resistance wire assembly unit according to the exemplary embodiment from FIG. 3a;

(8) FIG. 4a is sectional view showing a fourth exemplary embodiment of an electric cartridge type heater with the metallic jacket cut open and with the electrically insulating material partially removed;

(9) FIG. 4b is a perspective view showing the resistance wire assembly unit according to the exemplary embodiment from FIG. 4a;

(10) FIG. 5a is sectional view showing a fifth exemplary embodiment of an electric cartridge type heater with the metallic jacket cut open and with the electrically insulating material partially removed;

(11) FIG. 5b is a perspective view the resistance wire assembly unit according to the exemplary embodiment shown in FIG. 5a;

(12) FIG. 5c is a perspective view a variant of the resistance wire assembly unit according to the exemplary embodiment shown in FIG. 5a;

(13) FIG. 6a is sectional view showing a sixth exemplary embodiment of an electric cartridge type heater with the metallic jacket cut open and with the electrically insulating material partially removed;

(14) FIG. 6b is a perspective view the resistance wire assembly unit according to the exemplary embodiment shown in FIG. 6a;

(15) FIG. 7a is sectional view showing a seventh exemplary embodiment of an electric cartridge type heater, viewed in the cross section along the direction in which the electric cartridge type heater extends;

(16) FIG. 7b is sectional view showing the exemplary embodiment from FIG. 7a after an additional pressing step;

(17) FIG. 7c is sectional view showing the exemplary embodiment from FIG. 7a after an alternative additional pressing step;

(18) FIG. 8 is an exploded perspective view of an eighth exemplary embodiment of an electric cartridge type heater;

(19) FIG. 9a is sectional view showing a ninth exemplary embodiment of an electric cartridge type heater, viewed in the cross section along the direction in which the electric cartridge type heater extends;

(20) FIG. 9b is a perspective view showing the resistance wire assembly unit according to the exemplary embodiment shown in FIG. 9a;

(21) FIG. 10a is sectional view showing an assembly unit of an electric cartridge type heater before a compaction step;

(22) FIG. 10b is sectional view showing the assembly unit of an electric cartridge type heater from FIG. 10a after a compaction step, which leads to a conical contouring of the interior space; and

(23) FIG. 10c is sectional view showing a variant of the compaction according to FIG. 10b, which leads to a stepped contouring of the interior space.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(24) Referring to the drawings in particular, identical components of identical exemplary embodiments are designated by identical reference numbers in all figures. The features illustrated on the basis of individual embodiments can be applied to all other embodiments unless they are in direct conflict with one another.

(25) FIG. 1a shows an electric cartridge type heater 100 with a first tubular metallic jacket 101 and with a self-supporting electric resistance wire (heat conductor) 102 arranged in the interior tubular space of the first tubular metallic jacket 101 with two ends 102a, 102b for electrically contacting the self-supporting electric resistance wire 102. The self-supporting electric resistance wire 102 is electrically insulated from the first tubular metallic jacket 101 by an electrically insulating material 103, e.g., magnesium oxide, arranged in the interior space of the first tubular metallic jacket 101. The two ends 102a, 102b of the at least one self-supporting electric resistance wire 102 are received in connecting bolts 112a, 112b and are pressed to same. The connecting bolts 112a, 112b are led out of the first tubular metallic jacket 101 on the same side of said metallic jacket, namely, on the end face 105 thereof. A bottom 106, which closes the metallic jacket 101 on the connection-side end face 105, is located opposite that side.

(26) As is best recognized in the view of the resistance wire assembly unit 110 in FIG. 1b, the self-supporting resistance wire 102 extends in a coiled form and the end 102a of the resistance wire 102 extends in the space enclosed by the coils 104 in the direction of the connection-side end face 105 of the electric cartridge type heater 100. The electric resistance wire 102 shown in FIG. 1b is self-supporting, i.e., it only needs to be inserted into the interior space defined by the tubular jacket surface 101 for installation in the electric cartridge type heater 100.

(27) The possibility shown in FIG. 1c is pointed out, in particular, according to which the connecting bolt 112a can be designed in the resistance wire assembly unit 110 such that the contact is established at the end 102a of the resistance wire 102 in the space enclosed by the coils 104, so that a section of the connecting bolt 112a extends in this space. It is possible as a result to reduce the resistance of the electric return.

(28) The embodiment of the electric cartridge type heater 200 according to FIGS. 2a and 2b differs from the embodiment according to FIGS. 1a and 1b in that the resistance wire assembly unit 210 shown in FIG. 2b also has two positioning elements 207, 208, which guarantees the reproducible arrangement of the resistance wire assembly unit 210 in the metallic jacket 201. Further, a locally different heat output is achieved due to the variation of the coil pitches.

(29) An embodiment of the electric cartridge type heater 300 according to FIGS. 3a and 3b differs from the embodiment according to FIGS. 2a and 2b only in that the resistance wire assembly unit 310 shown in FIG. 3b has a positioning element 307, which is arranged at a spacer 309, which extends through the self-supporting resistance wire 302 and is designed as a rigid carrier. This makes it possible to improve the reproducibility of the assembly, not only in respect to the radial position of the self-supporting resistance wire 302, but also in respect to the longitudinal position of said resistance wire, i.e., the question of how far the self-supporting resistance wire 302 is to be pushed into the first tubular metallic jacket 301.

(30) The embodiment of the electric cartridge type heater 400 according to FIGS. 4a and 4b differs from the embodiment according to FIGS. 3a and 3b only in that the spacer 409 has a hole 411, through which the end 402a of the self-supporting resistance wire 402 extends in the space enclosed by the coils 404 to the connection-side end face 405 of the electric cartridge type heater, so that an undesired contact of the end 402a with another part of the self-supporting electric resistance wire 402 is prevented from occurring with certainty.

(31) The embodiment of the electric cartridge type heater 500 according to FIGS. 5a and 5b differs from the embodiment according to FIGS. 1a and 1b only in that, as can be best recognized in FIG. 5b, the ends 502a and 502b of the self-supporting resistance wire 502 are soldered to connection wires 512a, 512b and that the self-supporting resistance wire 502 has a section 502c leading away from the connection-side end face 505 of the electric cartridge type heater 500 and a section 502d, which is connected with that section in an electrically conducting manner and leads back to the connection-side end face 505, and these sections of the self-supporting resistance wire 502 are coiled one around the other, i.e., they have a bifilarly coiled design.

(32) FIG. 5c shows a variant of the resistance wire assembly unit according to the exemplary embodiment shown in FIG. 5a, in which a further change was brought about in the cross section of the resistance wire 502 after the deformation of the self-supporting resistance wire 502 into the resistance wire assembly unit shown in FIG. 5b. This is possible, for example, by a rod or a mandrel being pushed into the interior of the resistance wire coils, whose diameter essentially corresponds to the coil diameter, and by subsequently performing a radial pressing. The cross section of the resistance wire 502 is transformed hereby from a round to an oval shape, as a result of which a more compact structural shape becomes possible, in particular.

(33) The embodiment of the electric cartridge type heater 600 according to FIGS. 6a and 6b differs from the embodiment according to FIGS. 1a and 1b only in that the resistance wire assembly unit 610 shown in FIG. 6b has a meandering self-supporting electric resistance wire 602.

(34) The electric cartridge type heater 700 according to FIG. 7a differs from the electric cartridge type heater 500 according to FIG. 5a above all in that a second, inner tubular metallic jacket 713 is provided, which is arranged concentrically to the first tubular metallic jacket 701 in the interior of the bifilarly coiled self-supporting resistance wire 702, so that a hollow cartridge is formed. Another difference is that a layer 714 consisting of electrically insulating material having a thermal conductivity that is worse than that of the filling material 703, which material contributes to the heat being dissipated preferably in the direction of the interior space 715 of the second, inner tubular metallic jacket 713, is arranged between the first, outer tubular metallic jacket 701 and the bifilarly coiled self-supporting resistance wire 702.

(35) The embodiments of the electric cartridge type heater 700 shown in FIGS. 7b and 7c are obtained by radial pressing over the entire length of the cartridge type heater 700 (as is shown in FIG. 7b) or over a part of the length of the cartridge type heater (as is shown in FIG. 7c). It becomes clear especially when comparing the respective detail views A, B and C belonging to the figures with one another that a deformation of the self-supporting resistance wire 702 is also possible in this step as an alternative or in addition to a deformation of the self-supporting resistance wire 702 before they are inserted into the first, outer tubular metallic jacket 701.

(36) The exemplary embodiment of an electric cartridge type heater 800 shown in FIG. 8 as an exploded view differs from the embodiments shown in FIGS. 7a through 7c only in that no layer 714 is provided. Possible procedures in manufacturing the electric cartridge type heater 800 can easily become clear on the basis of FIG. 8. For example, the self-supporting electric resistance wire 802, which is preformed as a bifilar coil here, can be pushed over the second, inner tubular metallic jacket 813, the end-face end disk 806 can then be connected with the second tubular metallic jacket 813, and the assembly unit thus obtained can be pushed into the first, outer tubular metallic jacket 801. When filling with electric insulating material having good thermal conductivity, e.g., MgO powder, not shown in FIG. 8, the connection-side end face 805 can then be pushed over and fastened, and the entire arrangement can then be compacted radially.

(37) However, it is also possible, as an alternative, to start with the connection of the outer metallic jacket 801 and the end-face end disk 806 and to push subsequently in the self-supporting electric resistance wire 802 preformed as a bifilar coil here. The inner tubular metallic jacket 813 is then pushed into the interior space of the self-supporting electric resistance wire 802, the space between the outer tubular metallic jacket 801 and the inner tubular metallic jacket 813 is filled with electric insulating material having good thermal conductivity, e.g., MgO powder, not shown in FIG. 8, the connection-side end face 805 is pushed over and fastened, and the entire arrangement is finally optionally compacted radially.

(38) The embodiment of an electric cartridge type heater 900 shown in FIGS. 9a and 9b is a variant of the embodiment according to FIG. 1a, in which areas 902e and 902f of the self-supporting electric resistance wire are provided, which have different coil diameters. It is achieved hereby, in particular, that the middle positioning element, which has a step, is fixed.

(39) FIGS. 10a through 10c are intended to illustrate a possible procedure for producing an electric cartridge type heater 1000, more precisely a hollow cartridge, whose interior space 1020 has a contour. This procedure is carried out by pressing on a mandrel 1030, which has, on the one hand, the negative of the desired shape, e.g., on a conical mandrel 1030, as is shown in FIG. 10b, or on a stepped mandrel 1030, as is shown in FIG. 10c.

(40) While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.