JP2011119132A - Electric heater, manufacturing method for the same, and furnace equipped with electric heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric heater capable of maintaining a basic shape in spite of softening during heating and easily installing, to provide a manufacturing method for the electric heater, and to provide a furnace equipped with the electric heater. <P>SOLUTION: The electric heater has a plate-shaped heating element 10 where a current passage is formed by forming slits, and insulators 20 for supporting the heating element 10. The heating element 10 is supported by the insulators 20 at a pair of width-directional ends 13, 13 located in a width direction of the slits of the heating element 10. The heating element 10 has an arc shape convexed downward between the pair of width-directional ends 13, 13. The width-directional end 13 is inserted into a groove 23 formed on the insulator 20 in an approximately vertical direction Z, and the width-directional end 13 is locked in the groove 23 of the insulator 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric heater, a method for manufacturing the electric heater, and a furnace equipped with the electric heater. More specifically, a plate-like heating element in which a current path is formed by forming a slit, and an insulator that supports the heating element, and a pair of heating elements positioned in the width direction along the slit of the heating element. The present invention relates to an electric heater supported by the insulator at a width direction end, a method for manufacturing the electric heater, 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. This electric heater supports the heating element by bending the end of the heating element and sandwiching the bent portion between the first and second divided bodies of the insulator. However, in order to prevent the pull-out in the width direction due to deformation due to heat generation, the first and second divided bodies have to be formed with projecting locking portions and pressing portions, which has complicated the structure. . In addition, the bent portion must be locked by the locking portion, and the vicinity of the bent portion must be pressed by the pressing portion, so that the operation of attaching the heating element is complicated.

  As a method for supporting a heating element, for example, Patent Documents 2 and 3 are known. The resistance heating element of Patent Document 2 has a semi-cylindrical shape that protrudes upward, supports the top of the resistance heating element, and fixes the end of the heating element to the sintering device via a connecting portion. Therefore, the structure is complicated because the influence of the deformation of the heating element is absorbed by the connecting portion.

  In the heat treatment furnace of Patent Document 3, a plurality of belt-like heating elements in which a semicircular bottom portion and a straight side portion are connected by a connecting plate are fixed to the lead portions on each side portion. It was complicated.

JP 2002-359061 A Japanese Utility Model Publication No. 62-116484 JP 2003-240442 A

  In view of such conventional circumstances, an object of the present invention is to provide an electric heater, an electric heater manufacturing method, and a furnace equipped with the electric heater that can maintain the basic shape even by softening during heat generation and that can be easily mounted. And

  In order to achieve the above object, the electric heater according to the present invention is characterized by including a plate-like heating element in which a current path is formed by forming a slit, and an insulator that supports the heating element. In the configuration in which the insulator is supported by the pair of width direction end portions positioned in the width direction along the slit, the heating element has an arc shape that protrudes downward between the pair of width direction end portions. The width direction end portion is inserted into a groove formed in the insulator in a substantially vertical direction, and the width direction end portion is locked to the insulator in the groove.

  According to the above configuration, since the heating element is formed in an arc shape that protrudes downward between the pair of widthwise end portions, even if the heating element softens due to heat generation, the weight of the heating element remains in the vertical direction. It acts on Z, and its deformation can be induced in the vertical direction, resulting in a shape like a catenary curve. Since this shape is mechanically stable, the shape of the heating element is maintained and the dropout is prevented even when softened. In addition, it is only necessary to insert the end portion in the width direction of the heating element into the groove formed in the insulator in the substantially vertical direction, and the mounting operation becomes easy.

  The locking may be performed by forming a through hole at the end in the width direction and inserting an insulator into the through hole. Further, the end in the width direction may be bent to perform the locking. By these aspects, the end portion in the width direction can be reliably locked in the groove, and the heating element can be prevented from falling off. A part of the insulator may be constituted by an insulator, and the groove may be formed in the insulator.

  Moreover, you may provide the latching | locking part which latches the bending part of the said width direction edge part in the opening part of the said groove | channel. In such a case, the heating element can be easily attached to the groove by inserting the width direction end along the longitudinal direction perpendicular to the slit.

  The end portion of the lead member may be fixed to the intermediate portion in the width direction of the end portion of the current path positioned at the end portion in the longitudinal direction orthogonal to the slit and extended to the outside through the extension portion. By extending the lead member to the outside via the extension portion, it is possible to prevent a local temperature drop of the heating element due to the lead member, and uniform heating becomes possible. In addition, the extension member can follow the movement of the heat generating member due to the heat deformation, and can prevent the heat generating member from falling off due to the uneven heat deformation. The electric heater according to any of the above can be implemented as a furnace equipped with the electric heater.

  In order to achieve the above object, the method of manufacturing an electric heater according to the present invention is characterized in that in the method of manufacturing an electric heater according to any one of the above, a plate-like heating element in which a current path is formed by forming a slit; And an insulator that supports the heating element, and is a structure that is supported by the insulator at a pair of widthwise ends located in the width direction along the slit of the heating element. A through hole is formed, and the end in the width direction is inserted into a groove formed in the insulator in a substantially vertical direction, the liquid ceramic is filled in the groove, and the liquid ceramic is cured. In the groove, the end in the width direction is locked to the insulator.

  In order to achieve the above object, another electric heater manufacturing method according to the present invention is characterized in that, in the electric heater manufacturing method according to any one of the above, a plate shape in which a current path is formed by forming a slit. A heating element, and an insulator that supports the heating element, and a structure of the heating element that is supported by the insulator at a pair of widthwise ends located in the width direction along the slit, The groove is constituted by an insulator, the width direction end portion is oriented in a substantially vertical direction and the width direction end portion is bent, and the width direction end portion is inserted into the groove and the width direction end portion is inserted into the groove. The width direction end portion is locked to the insulator.

  According to the characteristics of the electric heater, the method for manufacturing the electric heater, and the furnace provided with the electric heater according to the present invention, the basic shape can be maintained even by softening during heat generation, and the heating element can be easily attached. It became.

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

It is a longitudinal cross-sectional view of the electric heater which concerns on 1st embodiment of this invention. It is the sectional view on the AA line of FIG. (A) is a top view of the thin plate member before a curve, (b) is a partial expanded side view of the width direction edge part of a heat generating body. It is a partial expanded sectional view of the insulator vicinity. (A) is the figure equivalent to FIG. 4 of the electric heater which concerns on 2nd embodiment of this invention, (b) is the partial expanded side view of the width direction edge part of the heat generating body in (a). FIG. 5 is a view corresponding to FIG. 4 showing a modification of the second embodiment. (A) is a longitudinal cross-sectional view of the electric heater which concerns on 3rd embodiment of this invention, (b) is the elements on larger scale near the edge part of the width direction of a heat generating body. It is a figure which shows the modification of 3rd embodiment, (a) (b) is a figure equivalent to FIG. 5 which shows a 1st modification, (c) (d) is the width direction end of the heat generating body which shows another modification. It is a partial expanded sectional view of the part vicinity. FIG. 5 is a view corresponding to FIG. 4 showing another embodiment according to the present invention. (A) and (b) are the expansion front views of the lead member vicinity which shows other embodiment concerning this invention, (c) is the expansion front view of the lead member vicinity of a comparative example.

Next, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, an electric heater 1 according to the present invention is mainly installed on the ceiling of a furnace, and includes a heating element 10 that heats the inside of the furnace, and an insulator that supports the heating element 10. 20. A lead member 30 that supplies power to the heating element 10 is connected to the heating element 10. The insulator 20 is attached to the frame 2 made of steel through an attachment member 40. The frame 2 includes a channel-shaped vertical frame 3 and a horizontal frame 4 that connects the vertical frames 3 to each other. The upper opening of the vertical frame 3 is intermittently fixed by the auxiliary material 3a to prevent deformation.

  As shown in FIGS. 1 to 3, the heating element 10 is formed in a plate shape and a rectangular shape, and has a meandering current path 12 by alternately cutting a plurality of slits 11 from the width direction X. ing. A plurality of substantially circular through holes 14 are formed in the pair of width direction ends 13 and 13 in the width direction X along the slit 11 in the heating element 10 at appropriate intervals. As shown in FIG. 1, between the pair of width direction end portions 13, 13 in the heating element 10 is formed so as to form a gentle arc shape (arch shape) in the longitudinal direction Y orthogonal to the slit 11. The lower side (furnace inner side) has a convex shape. When the heat generating element 10 is softened by heat generation and thermally expanded, the weight of the heat generating element 10 acts in the vertical direction Z and has a shape like a catenary curve. This shape is mechanically stable, and even when softened, the shape of the heating element 10 is maintained and falling off is prevented.

  As shown in FIG. 3, the heating element 10 is manufactured by first forming the slit 11 in the thin plate member 10 ′ cut to an appropriate size and penetrating the pair of end portions 13 ′ and 13 ′ in the width direction X. Hole 14 is formed. Then, the thin plate member 10 ′ is formed in an arc shape along the width direction X, the end portion 13 ′ is bent at the bent portion 15 to the inside of the arc formed by the thin plate member 10 ′, and the width direction end portion 13 is formed. Form. Here, bending to the inside of the arc means that both width direction end portions 13 and 13 are oriented parallel to each other along the substantially vertical direction Z. With this configuration, even if the heating element is softened by heating, the heating element 10 is vertically supported by the width direction end portions 13 and 13, and unnecessary stress is not generated in the support portion.

  The insulator 20 generally includes a pair of insulators 21, 21 and a pair of insulators 22 that allow the pair of insulators 21, 21 to pass through the through holes 14 of the heating element 10. A groove 23 into which the width direction end 13 is inserted is formed in the vertical direction Z. The pair of insulators 21 and 21 and the soot tube 22 are made of a so-called ceramic material or silicon nitride material mainly composed of alumina, alumina silica, mullite, zircon or cordierite, and the heating element 10 and the frame 2 are connected to each other. Insulate electrically.

  As shown in FIG. 4, a recess 24 is formed in each insulator 21, and a through hole 25 through which the soot tube 22 passes is formed in the recess 24. A groove 23 is formed by the recesses 24 and 24 by making the pair of insulators 21 and 21 face each other. Further, the insulator 21 is formed with an attachment hole 26 for attaching a fixture 42 such as a bolt or a nut fixed to the channel member 41. The channel member 41 is attached to the frame 2 by attachment means such as screws or welding.

  As shown in FIGS. 1 and 2, the end portion 31 of the lead member 30 is welded to the heating element 10 at an intermediate portion between the current path end portions 12 a and 12 b positioned at the end portion in the longitudinal direction Y orthogonal to the slit 11. Fixed. The lead member 30 includes an extension portion 32 extending in the width direction X from the end portion 31, and the extension portion 32 is formed of a thin plate member substantially similar to the heating element 10. The extension 32 is disposed along the heating element 10 and is not fixed to the heating element 10. The extension portion 32 is extended to the outside through a vertical portion 33 that extends in the vertical direction Z in the vicinity of the widthwise end portion 13 of the heating element 10.

  In general, the lead member is formed of a thick member to prevent heat generation of the lead member itself, has rigidity, and has a lower temperature than that of the heating element 10. In addition, since the lead member is connected to the outside, the heat of the heating element 10 is conducted to the outside. Therefore, as shown in FIG. 10C, when the lead member 30 ′ is fixed and bent in the vicinity of the width direction end portion 13 and extended to the outside through the vertical portion 33 ′, the vertical portion 33 ′ becomes the heating element 10. The heat is transferred to the outside and locally becomes low temperature. Moreover, the movement of the heat generating element 10 in the vertical direction Z is limited by the rigidity of the lead member 30 ′. As a result, uniform heating of the heating element 10 becomes difficult, and the balance of thermal deformation in the entire heating element 10 is lost.

  On the other hand, in the present embodiment as shown in FIGS. 1 and 2, the local temperature decrease of the heating element 10 can be suppressed by forming the extension portion 32 with a thin plate member. In addition, the extension 32 is not fixed only along the heating element 10, but extends from a substantially central part of the heating element 10 to the vicinity of the end 13 in the width direction. Therefore, the lead member 30 causes thermal deformation of the heating element 10. There is no restriction on movement. Therefore, the balance of thermal deformation is maintained throughout the heating element 10, and as a result, the heating element 10 is prevented from falling off.

Here, an assembly manufacturing procedure of the electric heater 1 in the present embodiment will be described.
First, the groove 23 into which the width direction end portion 13 of the heating element 10 is inserted is formed with the pair of insulators 21 and 21 facing each other. The end 13 in the width direction of the heating element 10 is inserted into the groove 23 from below. After the insertion, the soot tube 22 is inserted into and connected to the through hole 14 of the heating element 10 and the through holes 25 and 25 of the pair of insulators 21 and 21. These connected members are fitted into a channel member 41 attached in advance to the frame 2, and the insulators 21 and 21 are fixed so as to be clamped by the channel member 41 by a fixing tool 42. As a result, the end 13 in the width direction is locked to the soot tube 22 in the groove 23, and the heating element 10 is suspended from the insulator 20.

  Next, another embodiment of the present invention will be described. In the following embodiments, the same members as those in the first embodiment are denoted by the same reference numerals, and differences from the first embodiment will be mainly described.

  In the second embodiment shown in FIGS. 5 (a) and 5 (b), instead of the through hole 14 in the first embodiment, the tip end portion of the width direction end portion 13 of the heating element 10 is substantially the same as the width direction end portion 13. A bent portion 16 that is bent vertically is formed. The bending process of the bent portion 16 may be performed after the thin plate member 10 ′ is bent in an arc shape, and the width direction end portion 13 may be formed after the bent portion 16 is formed. The insulator 20 uses first and second insulators 21a and 21b having different shapes. The second insulator 21b is provided with a protruding locking portion 27 at one end. The widthwise end 13 is inserted and positioned in the recess 24a of the first insulator 21a, and the second insulator 21b is attached to the channel member 41 by the fixture 42 so as to face the first insulator 21a. Thereby, the bending part 16 of the width direction edge part 13 is latched by the latching | locking part 27, and omission of the heat generating body 10 is prevented. In this manner, the pair of insulators 21a and 21b may be fixed to face each other, and the heating element 10 can be easily attached.

  In the first modified example of the second embodiment shown in FIG. 6A, unlike the above embodiments, the insulator 21 c is fixed to the frame 2 without using the attachment member 40. The insulator 21c is formed with a groove 23c for inserting the width direction end portion 13 and an attachment hole 28 for attaching the fixture. Moreover, in the 2nd modification shown in FIG.6 (b), while providing the attachment hole 28 in the approximate center, a pair of groove | channels 23d and 23d are formed. By this insulator 21d, it becomes possible to install a plurality of heating elements along the width direction X. In these modified examples, the bent portion 16 formed in the width direction end portion 13 inside the grooves 23c and 23d is provided by providing the engaging portions 27 separate from the insulators 21c and 21d in the openings of the grooves 21c and 21d. It is locked.

  Unlike the first and second embodiments, an electric heater 1 according to the third embodiment shown in FIG. 7 includes a ceramic board 50 as an insulator. In the ceramic board 50, a groove 51 into which the width direction end 13 of the heating element 10 is inserted is formed in the vertical direction Z. In the present embodiment, the width direction end portion 13 of the heating element 10 is inserted into the groove 51 and the liquid ceramic 52 is injected and hardened to adhere the width direction end portion 13 of the heating element 10 within the groove 51. Lock.

As shown in FIG. 7B, the liquid ceramic 52 injected into the groove 51 penetrates into the through hole 14 of the heating element 10 and is cured. In the figure, for convenience of explanation, hatching showing the entire liquid ceramics 52 is omitted.
Here, thermal deformation also occurs in the vicinity of the through hole 14 of the heating element 10. Since the liquid ceramic in the region 52x in the vicinity of the edge 14x of the through hole 14 adheres to the edge 14x, it is easily affected by the thermal deformation and easily peeled off. On the other hand, the liquid ceramic in the region 52 y around the central axis M of the through hole 14 does not come into contact with the heating element 10, and therefore is not easily affected by thermal deformation in the vicinity of the through hole 14. Therefore, even if the liquid ceramic 52 is peeled off at the edge portion 14x, the liquid ceramic 52 in the vicinity of the central axis M of the through hole 14 is in communication, so that the heating element 10 is prevented from falling off. Alternatively, the liquid ceramic 52 may be injected and cured in a state where a pin as an insulator is inserted into the through hole 14. This pin can further improve the support strength of the heating element 10.

  In the first modification of the third embodiment shown in FIGS. 8A and 8B, a part of the width direction end 13 is punched and half-bent to form a punched portion 17 and a through hole 14a. ing. Further, in the second modified example shown in FIG. 8C, the width direction end portion 13 in which the bent portion 16 is formed is inserted and locked in the groove 51 by the liquid ceramics 52 as in the second embodiment. . Furthermore, in the third modified example shown in FIG. 8D, an insulator 53 as an insulator is attached to the groove 51 of the ceramic board 50. A groove 54 is formed in the insulator 53, and the end portion 13 in the width direction is inserted into the groove 54, and the liquid ceramic 52 is cured to lock the heating element 10.

Finally, the possibilities of yet another embodiment of the present invention are listed.
For example, as shown in FIG. 9A, an insulator 21e having a groove 23e and a mounting portion 29 may be used. In such a case, after the insulator 21e is attached to the frame 2 by the fixture 42 at the attachment portion 29, the width direction end portion 13 is inserted into the groove 23e, and the above-mentioned liquid ceramics 52 is filled and cured to make the width inside the groove 23e. The direction end 13 is locked. Further, as shown in FIG. 9B, it is also possible to use a substantially rectangular insulator 21f in which a groove 23f extending in the vertical direction Z is formed. In such a case, after the insulator 21f is attached to the channel member 41 attached to the frame 2 by the fixing device 42, the width direction end portion 13 is inserted into the groove 23f, and the liquid ceramics 52 is filled and cured, whereby the inside of the groove 23f. Then, the heating element 10 is locked.

  Further, as shown in FIG. 9 (c), an insulator 53 having a groove 54 formed in the vertical direction Z is inserted and attached to the groove 51 of the ceramic board 50, and the width direction end portion 13 is attached to the groove 54. After inserting, the locking piece 55 may be attached and the bent part 16 may be locked to the locking piece 55. The locking piece 55 may be formed integrally with the insulator 53. In such a case, the end 13 in the width direction of the heating element 10 is inserted into the groove 54 along the longitudinal direction Y, and the end 13 in the width direction is locked to the locking piece 55 in the groove 53. As described above, various modifications can be made without departing from the spirit of the present invention, and the above embodiments can be combined.

  In each of the above embodiments, the end portion 31 of the lead member 30 is attached to the substantially central portion of the current path end portions 12 a and 12 b located at the end portion in the longitudinal direction Y orthogonal to the slit 11. However, the attachment of the lead member 30 is not limited to the above embodiment. For example, as shown in FIG. 10A, the end portion 31 of the lead member 30 may be fixed near the width direction end portion 13 and the extension portion 32 a may be curved along the ceramic board 50. Absent. Further, as shown in FIG. 10B, it is possible to interpose a connecting portion 34 made of, for example, a nichrome wire between the extension portion 32b of the lead member 30 and the vertical portion 33. By configuring the connecting portion 34 with a member having flexibility such as a wire made of nichrome, it is possible to follow the movement of the heat generating element 10 in the vertical direction Z.

  Moreover, in each said embodiment, the electric heater mainly installed in the ceiling of a furnace was demonstrated. However, it can be installed not only on the ceiling of the furnace but also on the wall.

  The electric heater according to the present invention can be used as a heater for heat treatment of an object to be heated such as glass, ceramic, or metal. Moreover, it is applicable also to a reaction furnace and a diffusion furnace. Furthermore, the electric heater, the manufacturing method of the electric heater, and the furnace provided with the electric heater can be applied to, for example, a semiconductor manufacturing apparatus for semiconductor wafers, a substrate processing apparatus for heating a glass substrate, and the like.

1, 1a: Electric heater, 2: Frame, 3: Vertical frame, 4: Horizontal frame,
10: heating element, 10 ': thin plate member, 11: slit, 12: current path, 12a, 12b: current path end, 13: width direction end, 13': end, 14: through hole, 15: folding Curved portion, 16: bent portion, 17: punched portion, 20: insulator, 21, 21a to g: insulator (insulator), 22: insulator tube (insulator), 23, 23a to g: groove, 24, 24a : Recessed part, 25: through hole, 26, 26a, 26b, 26f: mounting hole, 27: locking piece (insulator), 28: mounting hole, 29: mounting part, 30, 30a, 30b: lead member, 31: End part, 32, 32a, 32b: Extension part, 33: Vertical part, 34: Connection part, 40: Mounting member, 41: Channel member, 42: Fixing tool, 50, 50a: Ceramic board (insulator), 51: Groove, 52: liquid ceramic, 53, 53a, 53b: insulator (insulator), 54 54a: Groove, 55: engaging piece (insulator), 60: supporting insulators, M: central axis, X: width direction, Y: longitudinal direction, Z: vertical direction

Claims (10)

A plate-like heating element in which a current path is formed by forming a slit, and an insulator that supports the heating element,
An electric heater supported by the insulator at a pair of widthwise ends located in the width direction along the slit among the heating elements,
The heating element has an arc shape that protrudes downward between the pair of widthwise ends,
An electric heater in which the width direction end is inserted into a groove formed in the insulator in a substantially vertical direction, and the width direction end is locked to the insulator in the groove. The electric heater according to claim 1, wherein a through hole is formed in the end portion in the width direction, and the locking is performed by inserting an insulator into the through hole. The electric heater according to claim 1, wherein the end in the width direction is bent to perform the locking. The electric heater according to any one of claims 1 to 3, wherein a part of the insulator is made of an insulator, and the groove is formed in the insulator. The electric heater according to claim 3 or 4, wherein a locking portion that locks the bent portion at the end in the width direction is provided in the opening of the groove. The electric heater according to claim 5, wherein the widthwise end of the heating element is inserted into the groove along a longitudinal direction perpendicular to the slit. The end of the lead member is fixed to the intermediate portion in the width direction of the end portion of the current path located at the end portion in the longitudinal direction orthogonal to the slit, and extended to the outside through the extension portion. Electric heater as described in. It is a manufacturing method of the electric heater in any one of Claims 1-7,
A plate-like heating element in which a current path is formed by forming a slit, and an insulator that supports the heating element,
Of the heating element, a structure is supported by the insulator at a pair of width direction ends located in the width direction along the slit,
A through hole is formed at the end in the width direction,
The width direction end is inserted into a groove formed in the insulator toward a substantially vertical direction, and the groove is filled with liquid ceramics,
A method for manufacturing an electric heater, wherein the liquid ceramics are cured to lock the end in the width direction with the insulator in the groove. It is a manufacturing method of the electric heater in any one of Claims 1-7,
A plate-like heating element in which a current path is formed by forming a slit, and an insulator that supports the heating element,
Of the heating element, a structure is supported by the insulator at a pair of width direction ends located in the width direction along the slit,
The groove is constituted by an insulator,
The width direction end portion is oriented in a substantially vertical direction and the width direction end portion is bent,
A method of manufacturing an electric heater, wherein the end in the width direction is inserted into the groove, and the end in the width direction is engaged with the insulator in the groove. The furnace provided with the electric heater in any one of Claims 1-7.

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