JPH07117340B2 - High temperature furnace - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high temperature furnace used for heating an object to be heated to a high temperature.

(Prior Art) Conventionally, a fan is provided inside the high-temperature furnace, and a prime mover for driving the fan is provided outside the furnace. The fan and the prime mover are connected by a rotation shaft to rotate the fan. Known high temperature furnace (Japanese Patent Laid-Open No. 57-
(See Japanese Patent No. 143425). However, when the temperature inside the furnace rises to around 1000 ° C, the required strength of the fan decreases. For this reason, the fan with the above configuration reduces the rotation speed to 1/2 to 1/4 to cope with this.

However, recent high-temperature furnaces require high-temperature treatment close to 2000 ° C. For example, to sinter ceramics,
A furnace with a furnace temperature of over 2000 ° C is used. And in such a furnace, in order to equalize the temperature inside the furnace and diffuse the gas generated in the furnace or the gas generated from the ceramic itself, it exerts a strong rotating force instead of low speed rotation as in the past. There is a demand for an in-furnace fan. Since the temperature inside the furnace is extremely high, a ceramic fan such as carbon, SiC, Si ₃ N ₄ or a composite material thereof must be used as the in-furnace fan.

Since the above-mentioned furnace has extremely high temperature as described above, its heat is transmitted through the shaft for rotating the fan, and is transferred to the outside of the furnace by its heat conduction, so that various equipment parts outside the furnace on the shaft become extremely high temperature. There is a problem to do. When the temperature of the shaft outside the furnace becomes high as described above, there is a problem that, for example, a bearing provided outside the furnace for supporting the shaft is abnormally heated. In order to solve the above problem, it has been considered to reduce the diameter of the shaft to reduce the heat conduction, but doing so causes a problem that the strength of the shaft is reduced. It is also possible to water-cool the shaft in the vicinity of the furnace wall, but water-cooling causes a problem that the temperature inside the furnace is locally lowered, which adversely affects the product.

(Problems to be Solved by the Invention) Except for the above-mentioned problems of the prior art, the present invention maintains the strength of the shaft at a high level and allows the shaft to be removed outside the furnace without exerting a thermal adverse effect on the inside of the high temperature furnace. It aims to provide a high temperature furnace that can significantly reduce the influence of high temperature of the furnace on the equipment located.

The configuration of the present invention is as follows.

(Means for Solving the Problems) The high temperature furnace of the present invention is provided inside the jacket, and inside the high temperature furnace, a fan for high temperature furnace using a ceramic as an impeller is provided, and In a high temperature furnace in which a fan driving prime mover is provided outside and the fan and the prime mover are connected by a rotating shaft to rotate the fan, when the fan is outside the high temperature furnace, Around the shaft that connects the prime mover, a temperature gradient zone with a large axial space is created between the fan side of the shaft and the prime mover side, and the shaft has heat transfer resistance. It is formed in a hollow shape in order to increase the size. In addition, inside the high temperature furnace prepared inside the jacket,
The impeller is equipped with a high temperature furnace fan that uses ceramics, and a prime mover for driving the fan is provided outside the jacket.The fan and the prime mover are connected by a rotation shaft to rotate the fan. In a high temperature furnace that is located outside the high temperature furnace, in the axial direction for causing a large temperature difference between the fan side and the prime mover side of the shaft around the shaft that connects the fan and the prime mover. A temperature gradient zone having a large space is provided, and a part of the shaft is made of a material having a low thermal conductivity so as to have a large heat radiation area and is hollow.

(Operation) The operation of the prime mover causes the high temperature furnace fan to rotate via the rotating shaft, so that the temperature inside the furnace is soaked or the gas generated in the furnace is diffused. Further, in that state, high heat in the furnace is transferred to the outside of the jacket through the shaft, but the shaft has a large temperature gradient in the axial direction for causing a large temperature difference between the fan side and the prime mover side. Since it is arranged in the zone and is formed in a hollow shape, the temperature of the shaft is greatly reduced as it moves away from the high temperature furnace.

(Example) Hereinafter, drawings showing an example of the present application will be described. Reference numeral 1 denotes a jacket, which has a water cooling structure, for example. Reference numeral 2 denotes a high temperature furnace provided inside the jacket 1, which is formed of a heat insulating material. 3 is a heater, and 4 is a high temperature furnace fan rotatably provided in the high temperature furnace 2. Reference numeral 5 indicates an object to be heated. Reference numeral 6 denotes a motor exemplified as a prime mover, which is connected to the jacket 1 via a mounting frame 7. Reference numeral 8 indicates a rotating shaft, one end of which is connected to the fan 4 in the furnace, and the other end of which is a connector 9
Are connected to the rotating shaft of the motor 6 via the. Also, in the jacket 1, on the motor 6 side of the furnace wall of the high temperature furnace 2 of FIG. 1, a large axial space is created to cause a large temperature difference between the fan side of the shaft 8 and the prime mover side. A temperature gradient zone is formed with. The shaft 8
Is configured by connecting a fan side shaft 10 connected to the fan 4 and a joint shaft 11 connected to the motor 6 with a connecting tool 12. The impeller of the fan 4 is made of ceramic such as graphite. The shaft 8 is formed to have an outer diameter of 40 mm and a length of 800 mm, for example, and the fan side shaft 10 is made of graphite and the joint shaft 11 is formed.
Is made of a material with strong strength and low thermal conductivity, such as heat-resistant steel and stainless steel such as SUS304, and is hollow (outer diameter 40 mm, inner diameter 20 mm). A bearing 13 provided in the jacket 1 is provided to support the intermediate portion of the rotating shaft 8.

In the case of the above configuration, the object to be heated 5 is heated by causing the heater 3 to generate heat. At the same time, the motor 6
Thus, by rotating the fan 4 via the shaft 8, the temperature in the high temperature furnace 2 can be made uniform, and the gas generated in the furnace can be uniformly diffused.

In the above case, since the joint shaft having high strength is used in the above structure, the rotation speed of the motor can be increased to rotate the fan at a high speed.

In the above state, the portion of the shaft 8 connected to the fan 4 is heated to a high temperature by the high heat in the high temperature furnace 2. The heat is transmitted to the outside of the furnace through the shaft 8. In this case, there is a temperature gradient zone having a large axial space around the shaft 8 for cooling, and the shaft 10,1
Shaft 8 because 1 is made of the above materials
The temperature distribution in each part of is like (a),
Although the temperature does not drop much near the furnace wall of the high-temperature furnace, the temperature at the bearing 13 portion is as low as 200 ° C. or lower. The bearing 13 is preferably set to about 300 ° C. or lower, and considering the grease used therein, it is preferably set to about 200 ° C. or lower. On the other hand, the structure described above can sufficiently satisfy the requirements. Incidentally, when the joint shaft 11 is formed of a solid material similar to the above, the temperature distribution is as shown in (b), and the shaft 8
When the entire length is formed of a solid ceramic material, the temperature distribution becomes as shown in (c), and the temperature at the bearing 13 portion becomes extremely high in all cases. On the other hand, the structure described above has the effect of being able to sufficiently lower the temperature of the bearing 13 as described above.

Next, the entire length of the rotating shaft 8 may be formed of a ceramic hollow material (for example, outer diameter 40 mm, inner diameter 20 mm).
When the shaft 8 is formed in this way, the temperature distribution becomes as shown in (d). Also in this example, as is apparent from the figure, the temperature of the portion of the shaft 8 outside the furnace can be made sufficiently low, and the temperature of the portion of the bearing 13 can be adapted to the above conditions.

Next, in the structure shown in FIG. 1, not only the connecting shaft 11 but also the fan-side shaft 10 may be made hollow with the above materials.

When the shaft 8 is hollow as described above, the hollow shaft is used to feed an atmospheric gas such as N ₂ gas from the motor side into the jacket 1 in a state of passing through the bearing portion, The bearing temperature can be lowered. Further, in order to lower the bearing temperature, the mounting frame 7 may have a hermetically sealed structure, and a cooling atmosphere gas may be injected into the mounting frame 7 and sent into the jacket 1 through the bearing 13.

Furthermore, a cover for covering the motor 6 can be attached to the jacket 1 or the attachment frame 7 in a closed structure, or the motor 6 can be attached inside the jacket 1. With such a structure, even if there is a gap in the motor 6 due to the structure or a gap in the mounting of the motor 6, the sealability with the outside air is maintained. It is possible to maintain the atmosphere.

(Effect of the Invention) As described above, in the present invention, the inside of the high temperature furnace 2 is
High temperature furnace fan 4 that uses ceramics for the impeller
And the fan 4 has a jacket 1
Shaft 8 connected to a prime mover 6 outside the
Since one end of is connected, the fan 4 can be rotated in the high temperature furnace 2 and can be used for soaking the temperature in the furnace or for diffusing gas generated in the furnace.

Moreover, in the present invention, the shaft 8 connecting the fan 4 in the high temperature furnace 2 and the prime mover 6 arranged outside the jacket 1 causes a large temperature difference between the fan side and the prime mover side. Is arranged in a temperature gradient zone having a large space in the axial direction, and by making the shaft 8 hollow, the heat transfer amount of the shaft 8 is reduced without significantly reducing the section modulus (without reducing the strength). From the above, the temperature of the shaft 8, which is heated to the high temperature side by receiving the high heat in the furnace, can be greatly reduced as it moves away from the temperature furnace 2. As a result,
Even if a bearing 13 is provided between the fan 4 and the prime mover 6, that bearing is also provided.
There is little risk of abnormal heating of 13 via shaft 8,
It has features that enable extremely safe long-term operation.

Further, in the present invention, the shaft 8 connecting the fan 4 in the high temperature furnace 2 and the prime mover 6 arranged outside the jacket 1 is cooled in the temperature gradient zone having a large space in the axial direction as described above. Therefore, there is little risk of locally lowering the temperature in the furnace, there is no fear of adversely affecting the inside of the furnace, and there is an effect that a good quality heat treatment can be applied to the product.

Moreover, in the present invention, the shaft 8 that connects the fan 4 in the high temperature furnace 2 and the prime mover 6 arranged outside the jacket 1 is connected by a hollow shaft 11 made of a material having a low thermal conductivity. In that case, there is also an effect that more of the above effects can be expected on the assumption that sufficient strength can be obtained.

[Brief description of drawings]

The drawings show embodiments of the present application, and FIG. 1 is a diagram schematically showing a vertical cross section of a high temperature furnace and also showing temperature distribution of a rotating shaft. 2 …… High temperature furnace, 4 …… High temperature furnace fan, 8 …… Rotating shaft, 11 …… Joint shaft.

Claims (2)

[Claims] 1. A high temperature furnace using ceramics as an impeller is provided inside the high temperature furnace provided inside the jacket, and a prime mover for driving the fan is provided outside the jacket. In a high-temperature furnace in which the fan and the prime mover are connected by a rotating shaft to rotate the fan, when the fan is outside the high-temperature furnace, the shaft of the shaft is connected around the shaft connecting the fan and the prime mover. A temperature gradient zone having a large space in the axial direction for creating a large temperature difference between the fan side and the prime mover side is provided, and the shaft there is formed in a hollow shape to increase heat transfer resistance. A high-temperature furnace characterized by being present. 2. A high-temperature furnace fan using ceramics for an impeller is provided inside the high-temperature furnace provided inside the jacket, and a prime mover for driving the fan is provided outside the jacket. In a high-temperature furnace in which the fan and the prime mover are connected by a rotating shaft to rotate the fan, when the fan is outside the high-temperature furnace, the shaft of the shaft is connected around the shaft connecting the fan and the prime mover. In addition to providing a temperature gradient zone with a large space in the axial direction to create a large temperature difference between the fan side and the prime mover side, part of the above shaft is a material with low thermal conductivity and has a large heat dissipation area. A high-temperature furnace characterized in that it is formed in a hollow shape.