Device for converting electricity into heat and electric heater with such a device

Abstract

A device (100, 200, 1100, 2100) converts electricity into heat. A first flat winding support (110, 130, 210a, 210b, 230a, 230b, 310a, 310b, 330a, 330b, 510, 610, 630, 710, 1110, 1130, 2110, 2130) including electrically insulating material, has a first electric heating element (140, 150, 240a, 240b, 250a, 250b, 340a, 340b, 350a, 350b, 540, 640, 650, 740, 750) wound thereon. The first flat winding support with wound first electric heating element is inserted into a housing (190, 290, 1190, 2190) electrically insulated against the housing. A second flat winding support, including electrically insulating material, has a second electric heating element (140, 150, 240a, 240b, 250a, 250b, 340a, 340b, 350a, 350b, 540, 640, 650, 740, 750), which is galvanically separated from the first electric heating element, wound thereon. The second flat winding support with wound second electric heating element is inserted into the housing electrically insulated against the housing.

Claims

1. A device for converting electricity into heat, the device comprising: a housing; a first flat winding support comprised of an electrically insulating material; first electrical insulation; a first electric heating element wound on the first flat winding support, the first electrical heating element supported in a wound state on the first flat winding support, being disposed in the housing and electrically insulated relative to the housing by the first electrical insulation; a second flat winding support comprised of an electrically insulating material; second electrical insulation; further electrical insulation; a second electric heating element wound on the second flat winding support galvanically separated from the first electric heating element by the further electrical insulation, the second electric heating element being disposed in the housing and electrically insulated relative to the housing by the second insulation such that first electric heating element and the second electric heating element are electrically insulated relative to the housing, wherein the first and second flat winding supports and the first and second electric heating elements are arranged in a stack inside the housing, the first electric heating element having terminals and the second electric heating element having terminals, the first electric heating element terminals being provided separate from the second electric heating element terminals, both of the first electric heating element terminals being located at a same end of the first flat winding support, the second electric heating element terminals being located at a same end of the second flat winding support; each of the first and second electrical heating elements having a first end and an opposite second end, respective said terminals of the each electrical heating element being located at the respective first end, the each electrical heating element having a winding with a first terminal end, a wound portion and a second terminal end, the each first terminal end being arranged at the respective first end of the respective one electrical heating element, the each wound portion extending from the first end of the respective one electrical heating element to the second end of the respective one electrical heating element, the wound portion being wound around the respective flat winding support, the each second terminal end extending from the second end of the respective each electrical heating element to the first end of the respective each electrical heating element, and extending adjacent to the wound portion, respective, the second terminal end of the first electrical heating element being on a return side of the first electrical heating element, the second terminal end of the second electrical heating element being on a return side of the second electrical heating element, the return sides of the first and second electrical heating elements being on different sides of the housing.

2. A device for converting electricity into heat in accordance with claim 1, wherein the further electrical insulation has a higher dielectric strength than the first and second electrical insulation.

3. A device for converting electricity into heat in accordance with claim 1, wherein the first and second electrical insulation and the further insulation each comprises at least one insulation plate consisting of an electrically non-conductive material or, at least one web, made of an insulation mat or an insulation film and consisting of an electrically non-conductive material, arranged between respective electric heating elements arranged in the stack for insulating the first and second electric heating elements from one another.

4. A device for converting electricity into heat in accordance with claim 3, wherein the at least one insulation plate or at least one web comprises a plurality of insulation plates or webs.

5. A device for converting electricity into heat in accordance with claim 1, wherein the first electric heating element and the second electric heating element comprise a different pattern winding, possess different physical properties, possess different cross sections or consist of different materials.

6. A device for converting electricity into heat in accordance with claim 1, wherein at least one of the flat winding supports has a multipart configuration and is formed as a stack of insulation plates.

7. A device for converting electricity into heat in accordance with claim 6, further comprising: another winding support; and another electric heating element, wound on the another winding support, located between two insulation plates of the multipart flat winding support.

8. A device for converting electricity into heat in accordance with claim 7, wherein the housing has a heating side configured to heat a body; a low one of the first and second electric heating elements and the another electric heating element is of a lower heat output or is for operation with a lower operating voltage, and a high one of the first and second electric heating elements and the another heating element is of a higher heat output or is for operation with a higher operating voltage, the high one of the heating elements being arranged closer to the heating side of the housing than the low one of the heating elements.

9. A device for converting electricity into heat in accordance with claim 1, wherein: each of the first and second electric heating elements are configured to be individually electrically selectable to provide heat; the housing surrounds the stack on five sides of the stack.

10. A device for converting electricity into heat in accordance with claim 1, wherein: each of the first and second electric heating elements are configured to be individually electrically selectable to provide heat; the housing completely surrounds the stack.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 is a perspective partially opened exploded view showing a first device for converting electricity into heat;

(3) FIG. 2 is a perspective view showing the components of which the device from FIG. 1 is composed;

(4) FIG. 3a is an oblique view from the top showing a configuration variant for a wound-on winding support;

(5) FIG. 3b is a bottom view showing the upper winding support of the configuration variant from FIG. 3a;

(6) FIG. 4a is a perspective partially opened view of a second device for converting electricity into heat;

(7) FIG. 4b is a side sectional view of the device for converting electricity into heat from FIG. 4a;

(8) FIG. 4c is another perspective view of a second device for converting electricity into heat;

(9) FIG. 4d is an enlarged detail from FIG. 4a;

(10) FIG. 4e is a first enlarged detail from FIG. 4b;

(11) FIG. 4f is a second enlarged detail from FIG. 4b;

(12) FIG. 4g is an enlarged detail from FIG. 4c;

(13) FIG. 4h is a perspective exploded view of the stacked arrangement of the device for converting electricity into heat from FIG. 4a;

(14) FIG. 4j is a perspective view showing a wound-on winding support, preconfigured for use in the device for converting electricity into heat according to FIG. 4a;

(15) FIG. 5a is a perspective partially opened exploded view showing another variant of a stacked arrangement for use in a device for converting electricity into heat;

(16) FIG. 5b is a perspective view showing a wound-on winding support preconfigured for use in the variant according to FIG. 5a;

(17) FIG. 6a is a schematic view of the cross section of a first exemplary embodiment of an electric heater for heating a pipe;

(18) FIG. 6b is a schematic view of the cross section of a second exemplary embodiment of an electric heater for heating a pipe;

(19) FIG. 7 is a perspective view showing another variant of a stacked arrangement for use in a device for converting electricity into heat;

(20) FIG. 8a is a perspective view showing another variant of a stacked arrangement for use in a device for converting electricity into heat; and

(21) FIG. 8b shows a partially cut away view of the stacked arrangement from FIG. 8a.

DESCRIPTION OF PREFERRED EMBODIMENTS

(22) Referring to the drawings, not all reference numbers are shown in all figures for the sake of clarity. Identical components of the same exemplary embodiments have the same reference numbers in all figures unless indicated otherwise.

(23) FIGS. 1 and 2 show a first exemplary embodiment of a device 100 for converting electricity into heat. The device 100 has a housing 190, in the interior of which two respective winding supports 110, 130, onto which a respective electric heating element 140, 150 is wound, are embedded. The device 100 is shown in the exploded view in FIG. 1, so that the distance between the individual components in the vertical direction is shown as being exaggeratedly great in order to allow a more detailed representation of the components.

(24) Depending on how the electric heating element 140, 150 is configured, especially in terms of the selected material and the cross section, and on how the winding supports 110, 130 are wound on, especially in terms of the number of turns and the winding pitch, heating circuits with different heat outputs can thus be provided in a very simple manner, and these heating circuits permit, depending on the actuation, different operating stages, or it is also possible to provide heating circuits for use with different voltage sources, e.g., the on-board voltage network of a vehicle, on the one hand, and the normal stationary a.c. voltage network, on the other hand.

(25) While it is also possible, in principle, to use rectangular or strip-shaped winding supports 110, 130, these always have projections 111a, 111b, 112a, 112b, 131a, 131b, 132a, 132b, which locally broaden the winding support 110, 130, in both end areas 111, 112 and 131, 132 in the exemplary embodiment shown, and the broadening is greater in this exemplary embodiment in one direction due to the projections 111a, 112a, 131a, 132a than the broadening in the other direction due to the projections 111b, 112b, 131b, 132b.

(26) All projections 111a, 111b, 112a, 112b, 131a, 131b, 132a, 132b have the purpose of ensuring that the electric heating element 140, 150, with which the respective winding support 110, 130 is wound on, is spaced apart from the housing 190.

(27) The projections 111a, 112a, 131a, 132a have, moreover, the function of making possible an electrical connection of the two ends of the electrical heating elements 140, 150 configured as a heating wire on the same side of the device 100 for converting electricity into heat by establishing a contact to a terminal wire 141, 151, which is returned to the terminal side parallel to the winding direction and spaced apart from the winding by the projections 111a, 112a, 131a, 132a, from the end of the winding, which end is opposite the terminal side, as is shown in the exemplary embodiment, via a contact point 113, 133 provided on the winding support 110, 130.

(28) It is, however, also possible, as an alternative to this, to return an end section of the electric heating elements 140, 150 parallel to the winding direction and through the projections 111a, 112a, 131a, 132a spaced apart from the winding to the terminal side and to establish the connection to a terminal wire there.

(29) The other end of the electric heating elements 140, 150 is electrically connected to an additional terminal wire 142, 152 via a contact point 114, 134 provided at the terminal-side end of the winding support 110, 130. The electrical connection at a contact point 114, 134 may be established especially by welding, riveting, crimping or soldering not only in this exemplary embodiment but quite generally as well.

(30) The wound-on winding supports 110, 130 are arranged next to each other in the device 100 for converting electricity into heat and are part of a stack, which also contains, moreover, electrically insulating insulation plates 120, 121, 122, which should, however, preferably have the best possible heat conduction. The insulation plates 120, 121, 122 may consist, for example, of Micanite.

(31) The electric heating elements 140, 150 are electrically insulated from one another by the insulation plate 120 and a galvanic separation is thus guaranteed between the electric heating elements 140, 150 especially in the area of the winding supports, while the electrical insulation of the electric heating elements 140 and 150 from the housing 190 is ensured by the insulation plates 121 and 122, respectively. However, individual insulation plates 120, 121, 122 or all insulation plates 120, 121, 122 may, in principle, also be insulated from one another and from the housing 190 by embedding in an electrically insulating, but heat-conducting powder or granular material, for example, magnesium oxide. The overall arrangement is preferably compressed together in both cases. This may preferably lead to a gap-free arrangement, in which the electric heating elements are then especially also pressed into insulation supports and/or winding supports.

(32) In two different perspectives, FIGS. 3a and 3b show an embodiment variant for a wound-on winding support 510, which can be used in all exemplary embodiments as an alternative to the winding supports shown there. The winding support 510 has a multipart configuration and comprises especially an upper insulation plate 590 and a lower insulation plate 591. Additional insulation plates may optionally also be arranged between the upper insulation plate 590 and the lower insulation plate 591. The winding support 510 is consequently configured as a stack of a plurality of insulation plates 590, 591.

(33) The electrical heating element 540 is wound in this configuration on the multipart winding support 510 thus formed around this stack of insulation plates, i.e., around the upper insulation plate 590 and the lower insulation plate 591 in the exemplary embodiment shown and is connected to terminal wires 541, 542 via contact points 514, 515.

(34) The multipart configuration of the winding support 510 has especially two effects:

(35) On the one hand, it is made possible hereby that, as is shown especially clearly in FIG. 3b, the end section 543 of the electric heating element 540 is returned in an electrically insulated manner between the upper insulation plate 590 and the lower insulation plate 591.

(36) On the other hand, the length of the electric heating element 540 wound on the winding support can be increased due to a multipart, stack-like configuration of the winding support 510, which may represent an important degree of freedom for providing a desired heat output.

(37) FIGS. 4a through 4j show a second exemplary embodiment of a device 200 for converting electricity into heat. The device 200 has a housing 290, in the interior of which four winding supports 210a, 210b, 230a, 230b, on which a respective electric heating element 240a, 240b, 250a, 250b is wound in the form of a heat conductor, are embedded. The electric heating elements 240 and 240b, on the one hand, and the electric heating elements 250a and 250b, on the other hand, are connected here in series, so that two heating circuits are likewise formed.

(38) As it becomes especially clear in the enlarged details enlarged on the same scale, which are shown as FIGS. 4e and 4f, the electric heating elements 240a and 240b have different configurations compared to the electric heating elements 250a and 250b both in terms of their cross section and in terms of the winding pattern, especially the number of turns and the winding pitch, so that two heating circuits with different heat outputs are present, which permit different operating stages depending on the actuation or can also be used with different voltage sources, e.g., with the on-board voltage network of a vehicle, on the one hand, and with the normal electric a.c. voltage network, on the other hand.

(39) While the use of rectangular or strip-shaped winding supports 210a, 210b, 230a, 230b is also possible, in principle, these have respective projections 211a, 211b, 212a, 212b, 231a, 231b, 232a, 232b, which locally broaden each winding support 210a, 210b, 230a, 230b, in the exemplary embodiment shown, the broadening being symmetrical in this exemplary embodiment. It is ensured hereby, in particular, that the wound-on areas of the winding supports 210a, 210b, 230a, 230b are spaced apart from the housing 290.

(40) The possibility of providing an electrical connection of the two ends of the electric heating elements 240a, 240b and 250a, 250b on the same side of the device 200 for converting electricity into heat is made possible here by the arrangement of these heating elements in pairs, in which the respective electric heating elements 240a and 240b as well as 250a and 250b are connected in series. This can be embodied in an especially simple manner by simply using the same electric heating element or the same heating wire for both windings, as is seen especially clearly in FIGS. 4h and 4j.

(41) It is therefore especially advantageous to provide projections 214a, 214b, 234a, 234b on the end face located opposite the terminals, via which projections a connection section 240c and 250c, respectively, of the electric heating element can then be led, which can be seen especially clearly in the enlarged detail shown in FIG. 4g.

(42) The electric heating elements 240a, 240b, 250a, 250b are then contacted each via contact points 213a, 213b, 233a, 233b provided on the winding supports 210a, 210b, 230a, 230b, via which a contact is established to a terminal wire 241a, 241b, 251a, 251b.

(43) As is seen especially clearly in FIG. 4h and in the enlarged detail that is shown in FIG. 4d, the wound-on winding supports 210a, 210b, 230a, 230b are arranged in the device 200 for converting electricity into heat one on top of another and area part of a stack, which also contains, moreover, electrically insulating insulation plates 221, 222, 223, 224, 225, which should preferably have the best possible heat conduction. The insulation plates 221, 222, 223, 224, 225 may consist, for example, of Micanite.

(44) The respective electric heating elements 240a, 240b and 250a, 250b belonging to one heating circuit are electrically insulated from one another by the insulation plates 222 and 224 such that short-circuits between the respective windings are avoided. The insulation plate 223 ensures this for the electric heating elements 240b and 250a, which are arranged adjacent to one another but belong to different heating circuits, while the electrical insulation of the electric heating elements 240a and 250b from the housing 290 is ensured by the insulation plates 221 and 225. Individual insulation plates or all the insulation plates 221, 222, 223, 224, 225 may, however, also be replaced, in principle, by embedding the electric heating elements 240a, 240b, 250a, 250b in an electrically insulating, but heat-conducting power or granular material, for example, magnesium oxide, for insulation from one another and from the housing 290. The overall arrangement is preferably compressed together in both cases. This may preferably lead to a gap-free arrangement, in which the electric heating elements are then especially also pressed into the insulation support and/or the winding support.

(45) A stack configuration expanded according to this configuration principle may, of course, also have even more heating circuits.

(46) FIGS. 5a and 5b show yet another variant of the arrangement of wound-on winding supports, which can be used for devices according to the present invention.

(47) Four winding supports 310a, 310b, 330a, 330b, on which a respective electric heating element 340a, 340b, 350a, 350b is wound in the form of a heating conductor, are present here as well, and the electric heating elements 340a and 340b, on the one hand, and the electric heating elements 350a and 350b, on the other hand, are connected in series, so that two heating circuits are likewise formed, but they are arranged next to one another rather than one on top of another in this variant.

(48) Essentially rectangular or strip-shaped winding supports 310a, 310b, 330a, 330b are used in this example; an electrical insulation in the lateral direction is brought about by bar-shaped insulation strips 380.

(49) The possibility of establishing an electrical connection of both ends of the electric heating elements 340a, 340b and 350a, 350b on the same side is made possible by the arrangement of said heating elements in pairs here as well, in which arrangement the respective heating elements 340a and 340b as well as 350a and 350b are connected in series. This can takes place by the provision of projections 314a, 314b, 334a, 334b on the end face located opposite the terminals here as well, over which projections a connection section 340c and 350c of the respective electric heating element is then led.

(50) The electric heating elements 340a, 340b, 350a, 350b are then contacted again via contact points 313a, 313b, 333a, 333b provided on the winding supports 310a, 310b, 330a, 330b, at which contact points a respective contact is established to a terminal wire 341a, 341b, 351a, 351b.

(51) As is seen especially clearly in FIG. 5a, the wound-on winding supports 310a, 310b, 330a, 330b are arranged in pairs one on top of another in the device 300 for converting electricity into heat and thus form a part of the stack, which also contains, moreover, electrically insulating insulation plates 321, 322, 323, which should preferably have the best possible heat conduction. The insulation plates 321, 322, 323 may consist, for example, of Micanite.

(52) The respective electric heating elements 340a, 340b and 350a, 350b belonging to one heating circuit are insulated electrically from one another by the insulation plate 322 such that short-circuits between the respective windings are avoided. The electrical insulation of the electric heating elements 340a and 350a as well as 340b and 350b from the housing, not shown, is ensured by the insulation plates 321 and 323, respectively.

(53) FIG. 6a shows a schematic view of an electric heater 1000 for heating a pipe 1001 with an external radius R in the cross section, wherein the plane of the cross section is located at right angles to the extension direction of the pipe 1001, i.e., at right angles to the direction in which a liquid flows through the pipe 1001. A device 1100 for converting electricity into heat, which corresponds in terms of the wound-on winding support 1110, 1130 and the arrangement thereof in the housing 1190 to the exemplary embodiment shown in FIGS. 1 and 2, is used, but the electric heating elements wound on the winding supports 1110, 1130 are not shown to improve clarity. Unlike in the exemplary embodiment according to FIGS. 1 and 2, the insulation of the winding supports 1110, 1130 and of the windings of the electric heating elements, not shown, which are arranged on them, from one another and from the housing 1190 is not ensured by the use of insulation plates, but by the use of insulation powder 1120, especially magnesium oxide.

(54) Depending on how the electric heating elements, not shown, are configured, especially in terms of the selection of the material and the cross section, and on how the winding supports 1110, 1130 are wound on, especially in terms of the number of turns and the winding pitch, heating circuits with different heat outputs can thus be provided in a very simple manner, which permit different operating stages depending on the actuation, or it is also possible to provide heating circuits for use with different voltage sources, e.g., the on-board voltage network of a vehicle, on the one hand, and the normal, stationary a.c. voltage network, on the other hand.

(55) The device 1100 for converting electricity into heat was shaped to assume a U-shape, in which the arc 1101 of the U, which connects the legs 1102, 1103 of the U, follows a semicircular contour, which is adapted to the external radius R of the pipe 1001.

(56) It is seen at the same time that a respective section 1110a, 1110b, 1130a, 1130b of the wound-on winding support 1110, 1130 also extends in the area, which is formed by the legs 1102, 1103 of the U and which extends over the center of the cross section of the pipe 1001. Not only is thus the mechanical seating of the device 1100 for converting electricity into heat on the pipe 1001 to be heated improved by the legs 1102, 1103 of the U, but it is also ensured that the part of the circumference of the pipe, via which heat can be introduced, is also enlarged or maximized.

(57) The exemplary embodiment of an electric heater 2000 for heating a pipe 2001 with an external radius R, which exemplary embodiment is shown in FIG. 6b in the same perspective as the perspective in FIG. 7a, likewise has a device 2100 for converting electricity into heat with a housing 2190 and with two wound-on winding supports 2110, 2130, whose windings are not shown for the sake of clarity and which are electrically insulated from the housing 2190 and from one another by insulation powder 2120, especially magnesium oxide.

(58) The device 2100 for converting electricity into heat was shaped for this purpose such that it assumes a U-shape, in which the arc 2101 of the U, which connects the legs 2102, 2103 of the U, follows a semicircular contour, which is adapted to the external radius R of the pipe 2001, wherein a respective section 2110a, 2130a of the wound-on winding supports 2110, 2130 also extends in the area formed by the legs 2102, 2103 of the U, which area extends over the center of the cross section of the pipe 2001, which leads to the same effects as in the case of the electric heater 2000.

(59) However, the electric heater 2000 differs from the electric heater 1000 in terms of the arrangement of the wound-on winding supports 2110, 2130, which are not stacked here, but are arranged next to one another each in a half of the U. This leads to an electric heater 2000, which leads only to a smaller enlargement of the cross section of the pipe in the area being heated with it and is thus well suited precisely for use in a small available installation space in this dimension.

(60) The variant of a stacked arrangement shown in FIG. 7 arises essentially from a different arrangement of wound-on winding supports, which are very similar to the winding supports shown in FIG. 2, namely, to an arrangement one on top of another rather than next to one another.

(61) FIG. 7 shows two winding supports 610, 630, on which are wound a respective electric heating element 640, 650 in the form of a heat conductor, and which are galvanically separated from one another by an insulation plate 620. The electric heating elements 640, 650 differ from one another here especially in terms of their cross section.

(62) The two ends of the electric heating elements 640, 650 are connected electrically on the same side of the winding supports 610, 630 in this example as well, but the return is via return plates 614, 634 here, which extend on different sides of the electric heating elements 640, 650.

(63) A “sandwich-like” arrangement of the electric heating elements 740, 750 is formed in the exemplary embodiment that is shown in FIGS. 8a and 8b. The inner electric heating element 740, configured for the operation with a higher output, is wound for this purpose onto a winding support 710, which is located between two insulation plates 790, 791, which are each broader than the wound-on winding support 710 and together form the winding support for the electric heating element 750, on the one hand.

(64) 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.

APPENDIX

(65) List of Reference Designations:

(66) 100, 200, 1100, 2100 Device 110, 130, 210a, 210b, 230a, 230b, 310a, 310b, 330a, 330b, 510, 610, 630, 710, 1110, 1130, 2110, 2130 Winding support 111, 112, 131, 132 End area 111a, 111b, 112a, 112b, 131a, 131b, 132a, 132b, 211a, 211b, 212a, 212b, 214a, 214b, 231a, 231b, 232a, 232b, 234a, 234b, 314a, 314b, 334a, 334b Projection 113, 133, 213a, 213b, 233a, 233b, 514, 515 Contact point 120,121, 122, 221, 222, 223, 224, 225, 321, 322, 323, 590, 591, 620, 790, 791 Insulation plate 141, 142, 151, 152, 241a, 241b, 251a, 251b, 341a, 341b, 351a, 351b, 541, 542 Terminal wire 140, 150, 240a, 240b, 250a, 250b, 340a, 340b, 350a, 350b, 540, 640, 650, 740, 750 Electric heating element 190, 290, 1190, 2190 Housing 380 Insulation strip 543 End section 1000, 2000 Electric heater 1001, 2001 Pipe 1101, 2101 Arc of the U 1102, 1103, 2102, 2103 Leg of the U 1110a, 1110b, 1130a, 1130b, 2110a, 2130a Section 1120, 2120 Insulation powder R External radius