JP2001194073A - Electric furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electric furnace for high temperature heating wherein the number of lead wires to be connected in the outside of the furnace is reduced, so the working efficiency can be raised, and also the number of holes for leading out terminals to be formed in a refractory board is reduced, so the heating efficiency can be improved. SOLUTION: A plurality of heaters are connected in series successively by connecting handles 14 of neighboring heaters 16 through connecting members 18. A plurality of non-penetrated channels 26 having openings to the inside on both ends of a cylindrical refractory board 22, and a plurality of through channels 28 connecting the inside and the outside are formed. The connection parts of the handles 14 of the heaters 16 are fit to the non-penetrated channels 26 to arrange a series of heater part within the refractory board 22. The handles 14 on both ends of the heaters 16 connected in series are fit to the channels 28 and the handles 14 are exposed to the outside of the board 22. Thus an electric furnace comprising a cylindrical refractory board 22, a heater part and handles 14 on both ends thereof is constructed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an electric furnace for high-temperature heating.

[0002]

2. Description of the Related Art A conventional electric furnace is shown in FIGS. The electric furnace 40 includes a tubular refractory board 44 in which a cylindrical space 42 is formed, and a heater 50 including a heater portion 46 and terminals 48 at both ends thereof. Fireproof board 4
In the space 42 of FIG. 4, a spiral heater 46 is disposed in contact with the wall surface of the fireproof board 44, and terminals 48 at both ends thereof are provided.
Are exposed to the outside of the refractory board 44. The terminals 48 at both ends are connected via a lead wire or a power supply (not shown).

The heater portion 46 is generally made of molybdenum disilicide (MoSiO ₂ ) as a main material, and when its temperature becomes high, its surface is covered with an oxide film such as silica (SiO ₂ ). Oxidation at high temperatures is prevented. On the other hand, the main material of the refractory board 44 generally comprises alumina and silica. The silica on the surface of the heater section 46 softens and dissolves at a high temperature of about 1500 ° C. or more, so that the contact portion between the heater section 46 and the refractory board 44 is fixed by the dissolved silica. Since the main material of the heater portion 46 and the main material of the refractory board 44 have different coefficients of thermal expansion, there is a problem that the heater portions 46 that are stuck to each other during cooling are pulled by the refractory board 44 and are broken. For this reason, the electric furnace shown in FIGS. 4 and 5 cannot be used as an electric furnace for heating to a high temperature of, for example, 1500 ° C. or more.

As an electric furnace for heating to a high temperature of 1500 ° C. or more, the one shown in FIGS. 6 and 7 is used. The electric furnace 60 mainly includes a tubular inner refractory board 64 having a cylindrical space 62 formed therein, a tubular outer refractory board 66 provided outside the inner refractory board 64, and an inner refractory board 64. And an end face refractory member 68 and a lower refractory member 70 provided above and below the outer refractory board 66,
A furnace core tube 72 provided in the inside of the furnace 2 and accommodating an object to be heated (not shown) therein;
And an opening / closing member 76 on the lower side of the furnace core tube 72, and a number of heaters 78 (FIG. 8) for heating the inside of the furnace core tube 72. Although FIGS. 6 and 7 show two fire-resistant boards, the inner fire-resistant board 64 and the outer fire-resistant board 66 outside the board, they may be combined into one fireproof board.

[0005] The heater 78 includes a pair of handle portions 80 each having a tip as a connection terminal, and a heater portion 82 connecting the pair of handle portions 80. The heater section 82 is mainly made of molybdenum disilicide (MoSiO ₂ ), and has a surface coated with silica (SiO ₂ ) at a high temperature. Heater 7
8, the cross-sectional area of the handle 80 is set to be at least three times larger than the cross-sectional area of the heater 82, and the resistance of the handle 80
Is sufficiently reduced, so that even if the temperature of the heater 82 rises to about 1500 ° C. or more, the
The temperature is set so that the temperature does not rise above ℃.

The handle portion 80 of each heater 78 penetrates through the inner fire-resistant board 64 and the outer fire-resistant board 66, and has a free end exposed outside the outer fire-resistant board 66. The handle portions 80 exposed to the outside of the outer refractory board 66 are sequentially connected by lead wires (not shown). On the other hand, the heater portion 82 is arranged outside the furnace core tube 72 in the space 62 and is set so as not to contact any of the inner refractory board 64 and the furnace core tube 72. In this way, by preventing the heater section 82 from contacting the inner refractory board 64 and the furnace core tube 72, the breakage of the heater section 82 can be prevented.
It is possible to heat the object to be heated at a high temperature of 0 ° C. or higher.

[0007]

As shown in FIGS. 6 and 7, in an electric furnace 60 in which a heater 78 is not in contact with an inner refractory board 64 or the like, two terminals are provided for each heater 78. The handle portion 80 is exposed outside the outer fire-resistant board 66, and the handle portions 80 must be connected to each other by a lead wire, and the connection work requires a large number of man-hours. . Further, when the inner refractory board 64 and the outer refractory board 66 are combined in a vertical direction in multiple stages to produce an electric furnace that is long in the longitudinal direction, there is a problem that the work of connecting lead wires becomes more difficult. Furthermore, since the periphery of the outer surface of the electric furnace 60 is covered with a lead wire through which a high-voltage current flows, there is a danger that work near the electric furnace involves danger and the working efficiency at the time of using the electric furnace is poor. In addition, since the fireproof boards 64 and 66 are formed with a large number of holes for drawing the handle 80 from the inside to the outside, heat leaks from the holes to the outside, resulting in poor thermal efficiency.

[0008] The present invention has been made in view of the above points, and by preventing the connection between the terminals of the heater from being exposed to the outside of the refractory board, the operation of connecting the terminals can be facilitated, and the electric furnace can be used. An object of the present invention is to provide an electric furnace in which the number of lead wires on the outside is greatly reduced to improve work efficiency in use, and the number of holes formed in a fireproof board is reduced to improve thermal efficiency. It is.

[0009]

To achieve the above object, an electric furnace according to the present invention comprises an electric furnace having a tubular refractory board, and a plurality of heaters each comprising a heater portion and handle portions at both ends thereof. A series of heaters are connected in series by sequentially connecting the handle portions of adjacent heaters, and a plurality of non-through grooves having both ends opened to the inside on the end face of the tubular fireproof board, and the inside and outside are connected. A plurality of through-grooves to be formed, and a connecting portion between the handle portions of the heater is fitted into the non-through-groove to arrange a series of heater portions inside the refractory board. The part is fitted into the through groove so that the handle is exposed to the outside of the fireproof board.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the electric furnace according to the present invention, FIG. 2 is a perspective view showing an assembled state of the electric furnace shown in FIG. 1, and FIG. 3 is a structural view showing a state in which many heaters are connected. is there. The electric furnace 10 of the present invention is the same as the conventional example shown in FIGS. 6 and 7 in that a large number of heaters 16 each including a heater section 12 and a handle section 14 at both ends thereof are used. However, in the electric furnace 10 of the present invention, the handle portions 14 of the adjacent heaters 16 are connected in order, and a large number of heaters 16 are connected in series. As shown in FIG. 3, the pattern portions 14 of the heater 16 are connected to each other by welding the pattern portion 14 of one heater 16 and the pattern portion 14 of the other heater 16 via a conductive connecting member 18. Fixed by. By repeating the fixing of the handle portions 14 sequentially, one heater in which a number of heater portions 12 are connected in series can be obtained. One in which a number of these heater sections 12 are connected in series
In each of the heaters, both ends serve as a terminal handle 20, and the length of the terminal handle 20 is set to be longer than the length of the handle 14.

The refractory board 22 of the electric furnace 10 has a cylindrical shape with a space formed therein.
A plurality of U-shaped non-through grooves 26 and an even number of through grooves 28 connecting the inside and the outside of the cylindrical shape are formed on the upper surface 24 which is the end face in the axial direction. Both ends of the U-shaped non-through groove 26 communicate with the inner space side. That is,
The non-penetrating groove 26 is set so as not to communicate with the outer outer surface of the fireproof board 22. U-shaped non-through groove 26
The shape is set so that a portion where the handle 14 of the one heater 16 and the handle 14 of the other heater 16 are fixed by the connecting member 18 can be fitted. Further, the through groove 28 is set in a shape that allows the terminal handle portion 20 to be fitted.

As shown in FIG. 2, a plurality of non-through grooves 26 formed on the upper surface 24 of the fireproof board 22 are provided with a pair of handle portions 1.
4 are fixed by the connecting member 18 sequentially, and the terminal handle 20 is fitted into the through groove 28. In a state where the portions where the pair of handle portions 14 are fixed by the connecting members 18 are fitted into the non-through grooves 26, the series of heater portions 12 are arranged inside the tubular fireproof board 22. Moreover, the heater unit 1
Reference numeral 2 denotes a furnace core tube which does not contact the refractory board 22 and is provided inside the refractory board 22 (the furnace core tube 7 shown in FIGS. 6 and 7).
(Corresponding to 2) is set so as not to contact with.
The length of the free end of the terminal handle portion 20 is set so as to be exposed outside the fireproof board 22.

A portion where the pair of handles 14 and the connecting member 14 are fixed is fitted into the non-through groove 26 and the terminal handle 2
After fitting the “0” into the through groove 28, the end face refractory member 30 is placed on the upper surface 24 of the refractory board 22, and the refractory board 24 and the end face refractory member 30 are fixed. Thereby, the non-penetrating groove 2
6 and the upper surface of the through groove 28 are covered with the end face fireproof member 30, and the non-through groove 26 communicates only with the internal space of the fireproof board 22 and does not communicate with the outside of the fireproof board 22. As a result, although a large number of heater portions 12 are provided inside the fireproof board 22, two terminal handle portions 20 project outside the fireproof board 22. FIG. 1 shows a state in which two terminal handle portions 20 are provided for approximately 180 degrees, but 360 terminal portions include four terminal handle portions 20.

In the above embodiment, one of the heaters 1
The handle 14 of the sixth heater 16 and the handle 14 of the other heater 16 are fixed via the connecting member 18. However, the handle 14 is directly connected in a U-shape without the connecting member 18, and further, The non-penetrating groove 26 formed on the upper surface 24 of the refractory board 22 may be formed in a V shape.

[0015]

As described above, according to the electric furnace of the present invention, adjacent terminals of a large number of heaters are connected in series, and the connected portions of the adjacent heaters are accommodated within the thickness of the fireproof board. It is also not exposed to the outside. Thereby, the number of terminals protruding to the outside of the fireproof board can be significantly reduced, and the work of connecting each terminal exposed to the outside of the fireproof board with a lead wire can be significantly reduced. This facilitates the work of connecting the lead wires even when manufacturing a multi-stage electric furnace that is long in the vertical direction. Further, since the number of lead wires connected outside the electric furnace is greatly reduced, the danger of work during operation of the electric furnace can be reduced, and work efficiency can be improved. In addition, the number of holes for drawing out the terminals formed on the refractory board can be reduced, thereby improving the conventional poor thermal efficiency.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of an electric furnace according to the present invention.

2 is an essential perspective view showing an assembled state of the electric furnace of FIG. 1;

FIG. 3 is a configuration diagram showing a state where a number of heaters are connected.

FIG. 4 is a longitudinal sectional view showing an example of a conventional electric furnace.

FIG. 5 is a plan view of FIG. 4;

FIG. 6 is a longitudinal sectional view showing an example of another conventional electric furnace.

FIG. 7 is a horizontal partial sectional view of FIG. 6;

8 is a front view of the heater used in FIGS. 6 and 7. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electric furnace 12 Heater part 14 Handle part 16 Heater 18 Connecting member 20 Terminal handle part 22 Fireproof board 24 Top surface 26 Non-through groove 28 Through groove 30 End face fireproof member

Claims (3)

[Claims] In an electric furnace having a tubular refractory board and a large number of heaters each comprising a heater portion and handle portions at both ends thereof, a plurality of heater portions are connected by sequentially connecting the handle portions of adjacent heaters. A series of connections, a plurality of non-through grooves opening both ends on the inner side and a plurality of through grooves connecting the inside and the outside are formed on the end face of the tubular refractory board, and the connection points between the handle parts of the heater are formed. Are fitted in the non-penetrating groove, a series of heaters are arranged inside the fireproof board, and the handle portions at both ends of the heaters connected in series are fitted in the through groove, and the handle portions of the fireproof board are connected. An electric furnace characterized by being exposed to the outside. 2. The electric furnace according to claim 1, wherein an end face refractory member is brought into contact with an end face of the refractory board so as to cover the upper surfaces of the non-through groove and the through groove. 3. The electric furnace according to claim 1, wherein the handle portions of the heater are connected to each other via a conductive connecting member.