JP2011124048A - Electric heater, and furnace equipped with electric heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric heater capable of stabilizing a heating element by rationally absorbing thermal deformation while supporting both side ends of the heating element, and to provide a furnace equipped with the electric heater. <P>SOLUTION: The electric heater is provided with a platy heating element 10 forming a current path by forming a slit, and a supporting body 20 supporting the heating element 10. The current path positioned at the middle part of a pair of width-direction end parts 13, 13 located in a width direction W along the slit is provided with a through-hole. The heating element 10 is supported by the support body 30 penetrating the through-hole at least with movement in a thickness direction Y and a width direction W regulated. The pair of width-direction end parts 13, 13 are regulated from movement in the thickness direction Y of the heating element 10 and allowed for movement in the width direction W, respectively, by an end-part through-hole or a support body 40 penetrating the slit. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric heater and a furnace equipped with the electric heater. More specifically, the present invention relates to an electric heater including a plate-like heating element in which a current path is formed by forming a slit, and a support body that supports the heating element, and a furnace including the electric heater.

  Conventionally, as an electric heater as described above, for example, the one described in Patent Document 1 is known. In this electric heater, the upper end of the heating element is fixed to the support, and the heating element is suspended and supported in a movable state without fixing the lower end. Thereby, thermal deformation of expansion / contraction due to heat generation / cooling of the heating element can be induced to the lower end portion, which is excellent in that the heating element is prevented from falling off. However, since the lower end is not fixed, there is a concern that the support of the heating element becomes insufficient.

JP-A-2005-150101

  In view of the conventional situation, the present invention provides an electric heater capable of rationally absorbing thermal deformation and stabilizing the heating element while supporting both ends of the heating element, and a furnace equipped with the electric heater. For the purpose.

  In order to achieve the above object, the electric heater according to the present invention is characterized in that a plate-shaped heating element in which a current path is formed by forming a slit and a support that supports the heating element are provided. A through hole is provided in a current path located in the middle of a pair of width direction ends located in the width direction along the slit, and the heating element is at least in the thickness direction by the support that passes through the through hole. The movement in the width direction is restricted and supported, and the pair of width direction end portions are restricted in movement in the thickness direction of the heating element by the support body that penetrates the end through hole or the slit, and the width. The movement in the direction is allowed.

  According to the said structure, a heat generating body is supported by the intermediate part of a width direction, and a pair of width direction edge part with a support body. Here, since the support body located in the intermediate part of the width direction restricts the movement of the heat generating body in the thickness direction and the width direction, the heat generating body can be stably supported around the support body. In addition, the support located at the end in the width direction allows movement of the heat generating element in the width direction, so that thermal deformation can be dispersed in the width direction. Therefore, even if thermal deformation occurs, the heating element can be stably supported. In addition, the said end part through-hole is good to form in the elongate hole along the said width direction.

  The support may include a pin that is fixed to a fixing member via a lever and protrudes from the fixing member toward the heating element. In such a case, the pin is preferably composed of a bolt and a nut. As a result, the heating element can be easily assembled.

  The heating element may be supported so that the width direction is the same as the vertical direction. The electric heater according to any of the above can be implemented as a furnace equipped with the electric heater.

  According to the characteristics of the electric heater and the furnace provided with the electric heater according to the present invention, it is possible to rationally absorb the heat deformation and stabilize the heating element while supporting both ends of the heating element.

  Other objects, configurations, and effects of the present invention will become apparent from the following embodiments of the present invention.

It is a schematic front view of the electric heater which concerns on 1st embodiment of this invention. It is a schematic side view of an electric heater. It is a schematic sectional drawing of the furnace which concerns on 1st embodiment of this invention. It is a partial expanded front view of a heat generating body. It is the elements on larger scale near the center support body. It is the elements on larger scale near the edge part support body. It is a schematic front view of the electric heater in 2nd embodiment of this invention. It is a schematic sectional drawing of the furnace which concerns on 2nd embodiment of this invention. FIG. 7 is a view corresponding to FIG. 6 in the second embodiment of the present invention. It is a partial expanded sectional view of the furnace which concerns on other embodiment of this invention.

Next, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the electric heater 1 according to the first embodiment of the present invention generally includes a plate-like heating element 10 and a support 20 that supports the heating element 10. The support 20 includes a center support (first support) 30 that supports the heating element 10 at its intermediate portion 10m, and an end support that supports the vicinity of the pair of widthwise ends 13 and 13 of the heating element 10, respectively. Body (second support) 40, 40. Each of these supports 30 and 40 is fixed to a metal inner member 50 as a fixing member.

  For example, as schematically shown in FIG. 3, the electric heater 1 is installed on a wall portion of the furnace 100, for example, and constitutes a heating unit 110. In the heating unit 110, for example, the heating element 10 and the inner member 50 are arranged concentrically, and are stacked in a plurality of stages in the vertical direction Z to constitute a heating device of the furnace 100. In this example, the inner member 50 constitutes a part of the wall portion of the furnace 100, and an object to be heat-treated is put into the heating space S that is inside the furnace covered with the heating element 10.

  As shown in FIGS. 1 and 4, the heating element 10 is made of a thin plate member made of a conductive material such as Fe—Cr—Al or nickel chrome alloy. The heating element 10 is configured to have a meandering current path 12 by alternately cutting a plurality of slits 11 in the vertical direction Z from the width direction W.

  The meandering current path 12 includes a linear portion 12 a located between a pair of width direction end portions 13 and 13 located at both ends (upper and lower ends) in the width direction W along the slit 11, and a width direction end portion 13. And a substantially rectangular communication part 12b for communicating adjacent linear parts 12a. A substantially circular through-hole 14 is formed in the center 10n in the width direction W of the linear portion 12a so as to penetrate a center support 30 described later. Moreover, the edge part through-hole 15 which penetrates the edge part support body 40 mentioned later is formed in one corner | angular part of the communication part 12b. The end through hole 15 is a long hole along the width direction W. In addition, although illustration is abbreviate | omitted, the heat generating body 10 is connected to the external temperature control apparatus via the lead member.

  Here, the heating element 10 expands and contracts due to its own heat generation and cooling, and its deformation stress mainly acts in the vertical direction Z due to its own weight. Further, the heating element 10 extends in the vertical direction Z by repeated expansion and contraction due to aging. Therefore, by providing the long-hole end through hole 15 in the width direction end portion 13, thermal deformation acting in the vertical direction Z is allowed by the inner diameter. Thereby, even if thermal deformation occurs, the heating element 10 can be stably supported.

  As shown in FIG. 5, the center support 30 generally includes a pin 31 that fixes the heating element 10 at its center 10 n and a pair of first insulators 34 and 34 that face each other with the inner member 50 interposed therebetween. The pin 31 includes a metal bolt 32 and a plurality of nuts 33, and is attached to the inner member 50 via first insulators 34 and 34.

  The bolt 32 penetrates the through hole 51 of the inner member 50 from the outside of the inner member 50 and protrudes toward the heating element 10, and penetrates the through hole 14 of the heating element 10. The center 10n in the width direction W of the heating element 10 is sandwiched between nuts 33 and 33 and fixed to the bolt 32. Thereby, the movement of the heating element 10 due to thermal deformation in the thickness direction Y and the width direction W is restricted, and the heating element 10 can be stably supported by the central support 30. Further, the thermal deformation of the heating element 10 is dispersed in the width direction W.

  As shown in FIGS. 1 and 5, the first insulator 34 has a substantially disk shape, for example, ceramics, silicon carbide, silicon nitride mainly composed of alumina, alumina silica, mullite, zircon, or cordierite. It is comprised with insulating materials, such as. In the center of the first insulator 34, a through hole 34a through which the bolt 32 is passed is formed. A projecting portion 34 b is formed at the center of the first insulator 34. The protrusion 34 b has substantially the same diameter as the through hole 51 of the inner member 50 and is formed so as to be able to fit into the through hole 51. The protrusion 34b positions the first insulator 34 with respect to the inner member 50, and the through hole 34a of the first insulator 34 and the through hole 51 of the inner member 50 are located concentrically.

  The first insulator 34 is fixed to the inner member 50 by a bolt 32 and a nut 33. Here, the through hole 34 a of the first insulator 34 is formed with a smaller diameter than the through hole 51 of the inner member 50. Therefore, the bolt 32 that fixes and supports the heating element 10 does not come into contact with the inner member 50, and insulation is ensured by the first insulator 34 and the through holes 34 a and 51.

  As shown in FIGS. 1, 2, and 6, the end support 40 is generally a substantially disc-shaped first insulator that sandwiches the pin 41 that penetrates the width direction end 13 of the heating element 10 and the inner member 50. 44 and a second insulator 45 that restricts the movement of the heating element 10 in the thickness direction Y. Here, the pin 41 and the first insulator 44 have the same configuration as the pin 31 and the first insulator 34 of the central support 30.

  The second insulator 45 has a substantially disk shape and is made of an insulating material similar to that of the first insulator 34 described above. In the center of the second insulator 45, a through hole 44a through which the bolt 42 is passed is formed. Further, an arc-shaped convex portion 45 b is formed on one side of the second insulator 45. The second insulator 45 is fixed to the bolt 42 by a nut 43 with the convex portion 45 b facing each other with the heating element 10 interposed therebetween. A gap 46 is formed between the second insulators 45. Since the end 13 in the width direction is allowed to move in the thickness direction Y by the gap 46, the dispersed thermal deformation is prevented from being unexpectedly deformed by the end support 40. In addition, since movement in the thickness direction Y beyond the gap 46 is restricted, disconnection of the heating element 10 due to contact between the heat-deformed heating element 10 and the inner member 50 is also prevented.

Next, a second embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the same members as those in the first embodiment.
As shown in FIG. 7, the electric heater 1 </ b> A according to the second embodiment is different from the first embodiment in that the end support 60 is passed through the end of the slit 11. It is not necessary to form the end through-hole 15 in the width direction end 13, and the heating element 10 can be easily manufactured.

  As shown in FIG. 8, the furnace 100 </ b> A including the electric heater 1 </ b> A according to the present embodiment is provided with a heat insulating member 52 such as a ceramic board on the furnace wall 101 side of the inner member 50, and the furnace wall 101 of the heat insulating member 52. A heat shield 53 is provided at the intermediate portion on the side. The heat insulating member 52 is provided with a second heat insulating member 52 a that suppresses heat transfer to the flange portion 59. The heat shield 53 is composed of three thin plates 54 made of a metal material such as stainless steel, and spacers 55 made of ceramic paper or ceramic cloth are provided at both ends of the thin plate 54. Thereby, the space 56 is formed between the thin plates 54, and the heat insulation of the heating space S is improved.

  In addition, the structure of the heat insulation member 52 and the heat shield 53 is not restricted to an aspect as shown in FIG. For example, as shown in FIG. 10A, it is possible to improve the heat insulation property by providing a heat insulating material 55 a such as ceramic paper or ceramic cloth between the thin plates 54. Further, as shown in FIG. 5B, a heat insulating member 52 ′ such as a ceramic board integrally formed on the furnace wall 101 side of the inner member 50 may be provided without providing the heat shield 53.

  As shown in FIG. 9, the end support 60 is generally composed of a pin 61 and a second insulator 65. The pin 61 has the same configuration as the pins 31 and 41 of the first embodiment. In the present embodiment, the pin 61 is fixed to the inner member 50 by a bolt 62 and a nut 63. In the present embodiment, unlike the first embodiment, insulation is not secured at the fixed portion to the inner member 50, but insulation is secured at the fixed portion of the heating element 10 by the second insulator 65.

  The second insulator 65 has a substantially disc shape and is made of an insulating material similar to that of each insulator of the first embodiment. A through hole 65a through which the bolt 62 passes is formed in the center of the second insulator 65, and a convex portion 65b is formed on one side of the second insulator 65. The convex portion 65 b is formed substantially equal to the width of the slit 11 and is inserted into the slit 11. Since the slit 11 allows thermal deformation in the width direction W, the heating element 10 can be stably supported even if thermal deformation occurs. Moreover, since the frictional resistance between the metal heating element 10 and the second insulator 65 made of a ceramic material or the like is small, thermal deformation in the width direction W is performed smoothly.

  The second insulator 65 is fixed to the bolt 62 by a nut 63 with the convex portion 65b facing the heating element 10A. Thereby, the convex part 65b is interposed between the slit 11 and the bolt 62 of the heating element 10, and insulation of the heating element 10 is ensured. Further, by making the second insulator 65 face each other via the slit 11, a gap 66 that allows movement in the thickness direction Y of the width direction end portion 13 is formed. Thereby, the unexpected deformation | transformation by the edge part support body 60 is prevented. Further, since movement in the thickness direction Y beyond the gap 66 is restricted by the second insulator 65, disconnection of the heating element 10 due to contact between the heat-deformed heating element 10 and the inner member 50 is also prevented.

Finally, the possibilities of yet another embodiment of the present invention will be described.
In each of the embodiments described above, the through hole 14 through which the central support 30 passes is formed in each linear portion 12a of the current path 12 located in the middle between the pair of width direction end portions 13 and 13. However, it is not necessary to form the through holes 14 in all of the linear portions 12a, and they may be provided at appropriate places in consideration of the expansion coefficient of the heating element 10 and the like.

  Moreover, the through-hole 14 was formed in the substantially circular shape in the approximate center of each linear part 12a. However, the position, number and shape of the through holes 14 are not limited to this. For example, a plurality of intermediate portions 10m of the heating element 10 may be provided. Moreover, it is good also as an elliptical through-hole along the width direction W or orthogonal. Furthermore, for example, linear portions 12a having through holes 14 and linear portions having no through holes may be alternately provided. That is, if the through hole 14 and the central support 30 can substantially fix and support the heating element 10 so as not to buckle due to thermal deformation, the intermediate portion of each current path is fixed. I don't need it.

  In each of the above embodiments, the width direction end portion 13 of the heating element 10 is formed in a substantially rectangular shape. However, the shape of the width direction end portion 13 is not limited to this, and may be formed in, for example, a semi-elliptical shape or a semi-circular shape.

  In each of the embodiments described above, a reflective layer may be formed on the surface of the inner member 50 on the heating space S side by gloss polishing treatment, sticking of a noble metal foil such as platinum or gold, or the like. Thereby, the radiant heat from the heat generating body 10 can be reflected to the heating space S, and heating efficiency can be improved.

  In each of the above embodiments, the heating element 10 is supported so that the width direction W of the heating element 10 is oriented in the vertical direction Z. However, the support of the heating element 10 is not limited to this, and the width direction W may be oriented in the horizontal direction, and the width direction W may be oriented so as to be inclined with respect to the vertical direction Z. Similarly, in addition to the case where the electric heater 1 is installed on the wall portion of the furnace 100, the present invention can be applied to a ceiling or a floor. Further, the heating element 10 was formed to be substantially flat so that the width direction W thereof was substantially parallel to the vertical direction Z. However, the shape of the heating element 10 is not limited to the above embodiment, and for example, it may be formed in a gentle arc shape protruding toward the heating space S side.

  Moreover, the 2nd support body in each said embodiment can also be implemented in combination.

  The electric heater according to the present invention and a furnace equipped with the electric heater can be used as a heater and a furnace for heat treatment for heating an object requiring heat treatment such as glass, ceramic, metal, and wafer.

1: electric heater, 10: heating element, 10m: middle part, 10n: center, 11: slit, 12: current path, 12a: linear part, 12b: communication part, 13: end in width direction, 14: through hole 15: end through hole, 20: support, 30: center support (first support), 31: pin, 32: bolt, 33: nut, 34: first insulator, 34a: through hole, 34b: Projection, 40: end support (second support), 41: pin, 42: bolt, 43: nut, 44: first insulator, 44a: through-hole, 44b: protrusion, 45: second insulator, 45a: through hole, 45b: convex portion, 46: gap, 50: inner member (fixing member), 51: through hole, 52, 52a: heat insulating member, 53: heat shield, 54: thin plate, 55: spacer, 55a : Heat insulating material, 56: space, 59: flange portion, 60: end support ( 2 support), 61: pin, 62: bolt, 63: nut, 65: second insulator, 65a: through hole, 65b: convex portion, 66: gap, 100: furnace, 101: furnace wall, 101a: outer member 101b: heat insulating member, S: heating space, W: width direction, Y: thickness direction, Z: vertical direction

Claims (6)

An electric heater comprising a plate-like heating element that forms a current path by forming a slit, and a support that supports the heating element,
A through hole is provided in the current path located in the middle of the pair of width direction ends located in the width direction along the slit,
The heating element is supported by the support that passes through the through hole, with movement restricted at least in the thickness direction and the width direction being supported,
The pair of width direction end portions is an electric heater in which movement in the thickness direction of the heating element is restricted and movement in the width direction is allowed by the support that passes through the end portion through holes or the slits. The electric heater according to claim 1, wherein the end through hole is a long hole along the width direction. The electric heater according to claim 1, wherein the support has a pin that is fixed to a fixing member via an insulator and protrudes from the fixing member toward the heating element. The electric heater according to claim 3, wherein the pin includes a bolt and a nut. The electric heater according to any one of claims 1 to 4, wherein the heating element is supported such that the width direction is the same as the vertical direction. The furnace using the electric heater in any one of Claims 1-5.

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