JPH1183342A - Heat-generating member support structure for electric furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-generating member support structure for an electric furnace, capable of exhibiting advantages such as the reduction of working hours, which heat-insulating blocks of a refractory material have intrinsically, simplifying the structure of a metal fitting for supporting a heat-generating member and making its mounting easier, and excellent in work processes and economy at the time of the construction of a furnace wall. SOLUTION: In this heat-generating member support structure for an electric furnace, the inside of an outer wall of a furnace body is lined with heat- insulating blocks 2 made of inorganic fibers of a refractory material, and a metal fitting 1 for supporting a heat-generating member, which has a heat- generating member support part at its head on one side and forms a tip end 1a on the other side, is inserted into an inner face of each heat-insulating block 2 to the depth less than the thickness of the heat-insulating block 2. Further, as another manner, a fitting metal for supporting a heat-generating member is used in which a horizontal metal plate is mounted to a bar-like part between a head 1b and a tip end 1c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heating element support structure of an electric furnace using an electric resistance heating element used for heat treatment of a metal material.

[0002]

2. Description of the Related Art Generally, a heating element of an electric furnace used for heat treatment of a metal material or the like is used for supporting a heating element disposed on an inner surface 11 of the furnace wall as shown in, for example, a front view inside the furnace wall in FIG. A ribbon-shaped electric resistance heating element 12 made of a nichrome alloy or the like is provided on a flanged insulator 10 in a zigzag manner.

[0003] There are various structures for installing a heating element.
For example, in Japanese Patent Publication No. 56-8943, first, a joint 6d is fixed to the inside of a furnace wall shell 8 with a mounting nut 6a as shown in FIG. 3 (see the front view of FIG. 3). . After that, a heat insulating material sheet having an arbitrary thickness of about 6 to 50 mm and made of inorganic refractory fiber such as ceramic fiber is sequentially laminated 7a while penetrating the joint 6d until the end is not covered. Next, the stud bolt 6 is screwed into the joint 6d and fixed. The interior of the joint 6d has an electrical insulation mechanism using an insulator, and the stud bolt 6 and the furnace wall outer shell 8 are electrically insulated. Then, further heat insulating material sheet,
Laminate 7b while penetrating stud bolts 6 until it reaches a predetermined thickness. After attaching both flanged insulators 6c to head 6b, they are fixed with bolts and nuts. After that, the electric resistance heating element 9 is installed on both the flanged insulators 6c. Here, the joint 6d may be fixed to the furnace wall outer shell 8 by other means such as welding.

On the other hand, in recent years, instead of laminating an inorganic refractory material fiber sheet on a heat insulating furnace wall, Japanese Patent Publication No. 5-799
No. 08, for example, the size is 400 mm
A heat insulating block made of inorganic refractory fibers of 400 mm x 300 mm has come to be used. The inorganic refractory fiber is one or a mixture of two or more selected from ceramic fiber, alumina fiber, mullite fiber, and zirconia fiber. This insulation block is attached directly or indirectly to the inside of the furnace wall shell. For example, Tokiko 6-3
In Japanese Patent No. 1684, a metal fitting provided in advance on a heat insulating block is connected to a metal fitting arranged inside a furnace wall outer shell and attached.

[0005]

The use of the above-mentioned heat-insulating block can save the trouble of constructing while laminating like the inorganic refractory fiber sheet, thereby speeding up the furnace wall construction work. Further, when the furnace wall is partially damaged by the operation of the electric furnace, only the heat insulating block at the damaged portion needs to be replaced, and the operation is completed quickly. Therefore, it is also advantageous in that it is used for repair.

However, the heat insulating block has a drawback that it can be applied only to a place where no heating element is installed. In order to install a heating element, it is necessary to attach a heating element support. If it is intended to mount a conventional metal fitting indirectly connected to the furnace wall as described in the above paragraph 0003, it is necessary to make a large number of through holes in the heat insulating block.
Further, after the fitting is inserted, it is necessary to close a gap formed between the fitting and the fitting with a refractory paste or the like. Therefore, the operation becomes very complicated, and the advantage of the heat-insulating block used at an angle is lost, which results in an increase in the number of steps and costs. An object of the present invention is to solve this problem and to provide a furnace wall construction method in which a heating element can be installed using a heat insulating block.

[0007]

According to a first aspect of the present invention, a heat insulating block made of inorganic refractory fiber is lined inside an outer wall of a furnace body, and one side of the heat insulating block is provided on an inner surface of the heat insulating block. A heating element supporting structure for an electric furnace, wherein a heating element supporting member having a heating element supporting portion on the head and having the other end pointed is inserted into a depth less than the thickness of the heat insulating block. The structure of the heating element support of the present invention is extremely simple. Further, it is not necessary to open a hole for the heating element support bracket in the heat insulating block. Further, since the tip of the heating element support metal does not reach the metal part of the furnace wall outer shell, it is electrically insulated and also thermally shielded from the outside. As a result, a structure in which man-hours and costs for constructing the furnace wall are greatly reduced is obtained.

A second invention is a heating element support structure of an electric furnace in which a horizontal metal plate is attached to a rod portion between a head and a point of the heating element support bracket of the first invention. During the operation of the electric furnace, the heating element supporting bracket is in a state of rising to a high temperature, and when the weight of the installed electric resistance heating element is large, the heating element supporting bracket is easily bent downward due to the weight of the heating element. In order to prevent the bending of the heating element support metal, a metal plate is mounted in a horizontal direction. The attachment of the metal plate increases the downward pressing area on the heat-insulating block supporting the heating element support fitting, thereby preventing the heating element support fitting from being bent. When the metal plate is attached, the structure becomes slightly more complicated than that of the first embodiment, but still, when constructing the furnace wall, it is only necessary to pierce the heat insulating block, which greatly increases the number of work steps. It doesn't matter.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a heat insulating block is not specified, but is described in, for example, Japanese Patent Publication No. 5-79908.
As shown in Japanese Unexamined Patent Application Publication No. H10-205, a fiber made of commercially available inorganic refractory fiber is used. The heating element support bracket is also made of commercially available stainless steel or a heat-resistant alloy, and its material is not specified. An insulator such as a flange made of ceramics is attached to the heating element support portion of one of the heads in a generally known structure. Alternatively, the electric resistance heating element may be brought into direct contact with the support metal by simply bending the head of the support metal into an L-shape without mounting the insulator. In short, the heating element support portion may be made of any shape, structure, and material according to the intended use, and it is only necessary that the electric resistance heating element can be installed. The other is a point
This is to stab the insulation block. The piercing is performed by pressing or hitting the head. The piercing depth can be fixed more stably when it is deeper, but if it exceeds the thickness of the heat insulating block, an electrical short circuit occurs with the furnace wall outer shell.

Next, in the second invention, the metal plate mounted in the horizontal direction is mounted by welding, but may be mounted by other means. Although the shape of the metal plate is not specified, it is preferable that the piercing side is pointed to facilitate piercing into the heat insulating block. The material of the metal plate is commercially available stainless steel or a heat-resistant alloy, but stainless steel is preferable from the viewpoint of economy.

[0011]

Embodiment 1 FIG. 1 is an explanatory view of a side view cross section of a first embodiment of the present invention. A heating insulator supporting bracket 1 made of a SUS304 stainless steel round bar having a diameter of 8 mm and a length of 250 mm is provided with a ceramic double flanged insulator 1c. On the other hand, inside the furnace wall shell 3 made of iron plate,
Insulation block 2 mx 300 mm wide x 300 mm thick
(Product name: Z Durablock manufactured by Toshiba Monoflux Co., Ltd.) (lining details are not shown). The tip 1a of the heating element supporting bracket 1 was pressed against the inner surface 2a of the heat insulating block 2 and pierced to a depth of 200 mm to obtain the structure of the first invention of the present invention. A ribbon-shaped nichrome wire heating element 4 was mounted on the insulator 1c and used.

Embodiment 2 FIG. 2 is an explanatory view of a cross section in plan view of a second embodiment of the present invention. A ceramic-made double-flanged insulator 1c is mounted on a head 5b of a heating element supporting member 5 made of a round bar of a heat-resistant alloy (material name: Inconel) having a diameter of 8 mm and a length of 250 mm. One metal plate 5c is mounted horizontally below the rod portion on the rod portion between the head 5b and the point 5a. The metal plate 5c is made of a thin plate of SUS310S stainless steel. Width 30mm x total length 110mm x thickness 2
mm, it has a pentagonal shape pointed toward the point 5a, and the center in the width direction is fixed to the lower side of the rod-like portion by four point welding. The heat insulating block 2 lined with the furnace wall outer shell 3 made of iron plate is the same as that of the first embodiment. The tip 5a of the heat-generating body support fitting 5 was applied to the inner surface 2a of the heat-insulating block 2, and the head 5b was hit and pierced to a depth of 200 mm to obtain the structure of the second invention of the present invention. Although the metal plate 5c was a single plate,
One side may be formed and each may be attached to the left and right of the bar. As in Example 1, a ribbon-shaped nichrome wire heating element 4 was provided on the insulator 1c for use.

Example 3 An electric furnace having an inner volume of 2 m in length, 2.5 m in width and 6 m in depth using a ribbon-shaped nichrome wire heating element having a width of 25 mm and a thickness of 2 mm, the length of one central side wall in the depth direction. 600mm
× The range of 900 mm in width was taken as the structure of Example 1, and the range of 600 mm in length × 900 mm in width of the other side center wall in the depth direction was taken as the structure of Example 2. The other portions have a laminated structure similar to that of the reference example in paragraph 0003 using a ceramic fiber sheet. In each structure, the distance between the left and right of the heating element support bracket 1 or 5 or the stud bolt 6 is 80 mm,
The distance between the upper and lower rows is 200 mm. This electric furnace was experimentally used 10 times for heat treatment at a maximum heating temperature of 1150 ° C. Although each heat treatment cycle time is longer or shorter, it is a period of about 1.5 months of test use. In the structural parts of Examples 1 and 2, there was almost no pain in the support brackets coming off, bending, falling off, and the heat insulating block, and the degree of pain due to use was less than that of the surrounding ceramic fiber sheet laminated structure. From this, it became clear that the heating element support structure of the electric furnace of the present invention can be put to practical use and is suitable for partial repair.

Example 4 The entire furnace wall of the electric furnace having the same furnace volume as in Example 3 was constructed with the structure of Example 2. The used ribbon-shaped nichrome wire heating element and its erection specification are also the same as in the third embodiment. This electric furnace was used 50 times for the heat treatment at the maximum heating temperature of 1150 ° C for about 6 months, but there was almost no detachment, bending, and falling off of the support bracket, and there was no significant pain of the heat insulation block.
It was sound. From this result, it is clear that the heating element support structure of the electric furnace of the present invention has sufficient practicality and durability.

The heating element supporting structure of the electric furnace according to the present invention exhibits advantages such as shortening of the working time inherent in the refractory heat insulating block, and the structure of the heating element supporting bracket and its attachment are simple. As a result, the present invention is effective in improving workability and cost reduction when constructing an electric furnace, improving durability when used, and improving electric insulation. Further, it is effective in facilitating and speeding up the work for partially repairing the furnace wall.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a cross section in a side view of a first embodiment of the present invention.

FIG. 2 is an explanatory view of a cross section in plan view of a second embodiment of the present invention.

FIG. 3 is a side view of a reference example of a heating element supporting structure of a conventional electric furnace having a laminated heat insulating material sheet.

FIG. 4 is an explanatory view of a front side inside a furnace wall of a general electric furnace in which an electric resistance heating element is installed.

[Explanation of symbols]

1; Heating element support bracket 1a;
b; head 1c; double flanged insulator 2; heat insulating block 2
a; inner surface 3; furnace wall outer shell 4; nichrome wire heating element 5
A heating element supporting bracket 5a; a tip 5b; a head 5
c; metal plate 6; stud bolt 6a; mounting nut 6
b; head 6c; insulator with both flanges 6d; joint 7
a; laminated heat insulating material 7b; laminated heat insulating material 8; furnace shell 9
An electric resistance heating element 10; a flanged insulator 11; a furnace wall inner surface 1
2: Electric resistance heating element

Claims (2)

[Claims] 1. A heating element support made of an inorganic refractory fiber and lined on the inside of an outer wall of a furnace body, and a heating element supporting portion on one head and a pointed end on the inner surface of the heat insulating block. A heating element support structure for an electric furnace, wherein a metal fitting is inserted into a depth less than a thickness of the heat insulating block. 2. A heating element support structure for an electric furnace according to claim 1, wherein a horizontal metal plate is attached to a rod portion between the head and the point of the heating element support bracket.