JP2007024355A - High-temperature heat treatment furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-temperature heat treatment furnace capable of improving temperature uniformity of a core pipe, and simultaneously preventing deformation of the core pipe at high temperatures. <P>SOLUTION: In this high-temperature heat treatment furnace which comprises a right cylindrical core pipe approximately horizontally mounted and composed of a heat-proof material, and a heating means storing the core pipe and heating it, and in which a furnace body inner wall is insulated by a heat insulating material, an area positioned inside of the heat treatment furnace of the core pipe is continuously supported by a heat insulating core pipe supporting base. Further a core pipe supporting member for supporting the core pipe, is mounted between the core pipe and the core pipe supporting base. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-temperature heat treatment furnace used in a high-temperature heat treatment process such as heat treatment of a thermocouple, and more particularly to a high-temperature heat treatment furnace having excellent soaking properties.

In a high-temperature heat treatment furnace, a furnace core tube made of a material such as ceramics such as alumina or a heat-resistant metal (a tubular tube used in a high-temperature heat treatment process such as heat treatment, which accommodates a member to be heat-treated inside. Although it is sometimes called a furnace shell or a process tube, it is called “furnace core tube” in this specification.) Since it softens at high temperatures, it is supported at both ends of the core tube in a conventional high-temperature heat treatment furnace. In addition, several support stands or support rods are provided near the center of the furnace core tube to prevent the furnace core tube from bending. For example, in JP-A-6-241658, in order to prevent the ceiling of the furnace shell from creeping and dropping due to a high temperature during heat treatment, the ceiling of the furnace shell is lifted and the ceiling is held in an appropriate position. A horizontal atmosphere heat treatment furnace having a plurality of independent mechanisms having a function to perform is described.
Japanese Patent Laid-Open No. 2000-58467 discloses that both sides of a process tube are held by a pair of left and right holding members made of a heat-resistant material to restrain deformation of the process tube in the radially outward direction. Describes a heat treatment furnace that prevents deformation of the process tube due to heat.
JP-A-6-241658 JP 2000-58467 A

  In conventional high-temperature heat treatment furnaces, several support bases or support rods are provided near the center of the furnace core tube, so heat escapes locally from the furnace core tube support part, resulting in uniform temperature distribution. The heat becomes worse. In other words, in the conventional mechanism that supports the vicinity of the center of the furnace core tube by the support base or the support rod, although the heat efficiency as a whole is good, the heat escapes in the vicinity of the support portion, so the axial direction of the furnace core tube There was a problem that the uniformity of temperature in the case deteriorated. Further, in the case where several support bases or support rods are provided near the center of the furnace core tube, there is a problem in that the high temperature furnace core tube sags due to gravity between the support portions.

  The present invention has been made in order to solve the problems of the prior art, and provides a high-temperature heat treatment furnace that improves the temperature uniformity of the furnace core tube and at the same time prevents deformation of the furnace core tube at high temperatures. The purpose is to provide.

In order to achieve the above object, a high-temperature heat treatment furnace of the present invention comprises a straight cylindrical furnace core tube made of a heat-resistant material, and a heating means that accommodates and heats the furnace core tube. In the high-temperature heat treatment furnace in which the furnace body wall is thermally insulated with a heat insulating material, a region located inside the heat treatment furnace of the furnace core tube is continuously supported by a heat insulating furnace core tube support.
The high temperature heat treatment furnace of the present invention is characterized in that a furnace core tube support member for supporting the furnace core tube is disposed between the furnace core tube and the furnace core tube support base.
The high-temperature heat treatment furnace of the present invention is characterized in that, in the longitudinal direction of the furnace core tube support member, the central part is formed of a material having high thermal conductivity and both ends are formed of a material having low thermal conductivity. .
In the high temperature heat treatment furnace of the present invention, a plurality of plate-like upper heat insulating materials are arranged in the longitudinal direction of the furnace core tube on the upper inner wall of the furnace body, and a U-shaped heater is attached to each plate-like upper heat insulating material. It is characterized by doing.
Further, the high temperature heat treatment furnace of the present invention is characterized in that the furnace core tube end heat insulating material supporting both ends of the furnace core tube is separated from the heat insulating material on the wall of the furnace body and spaces are provided above and below the furnace core tube end heat insulating material. And

The present invention has the following excellent effects.
(1) The temperature uniformity in the furnace of the high-temperature heat treatment furnace is compared with the conventional one by continuously supporting the region located inside the heat treatment furnace of the furnace core tube with a heat-insulating furnace core tube support. It can be improved by at least 6 times. In particular, a thermocouple manufactured using the apparatus of the present invention has high homogeneity that could not be achieved in the past. Homogeneity is the most important factor in determining the accuracy of thermocouples. With the advent of the device of the present invention, it has become possible for the first time to produce highly accurate thermocouples.
(2) Even when the apparatus of the present invention was used at 1600 ° C. for 100 hours, no distortion of the furnace core tube occurred.
(3) By placing a furnace core tube support member for supporting the furnace core tube between the furnace core tube and the furnace core tube support base, the reaction between the furnace core pipe and the furnace core tube support base can be achieved even in a high temperature state. Can be prevented.
(4) In the longitudinal direction of the furnace core tube support member, the central portion is formed of a material having high thermal conductivity and both ends are formed of a material having low thermal conductivity, so that heat from both ends of the furnace core tube is reduced. It is possible to prevent escape and lengthen the soaking part of the furnace core tube, and further improve the soaking property of the center part of the furnace core tube.
(5) A plurality of plate-like upper heat insulating materials are arranged in the longitudinal direction of the furnace core tube on the upper inner wall of the furnace body, and a U-shaped heater is attached to each plate-like upper heat insulating material, so that when a heater fails Only the upper heat insulating material supporting the heater can be taken out and the heater replacement operation can be performed.
(6) By separating the furnace core tube end heat insulating material supporting both ends of the furnace core tube from the heat insulating material on the wall of the furnace body and providing spaces above and below the furnace core tube end heat insulating material, It is possible to prevent stress on the furnace core tube due to a change in height due to expansion or compression.

  The best mode for carrying out the high-temperature heat treatment furnace according to the present invention will be described below with reference to the drawings based on the embodiments.

FIG. 1 is a side sectional view schematically showing a high temperature heat treatment furnace of the present invention, and FIG. 2 is a sectional view taken along the line α-α in FIG.
The high-temperature heat treatment furnace mainly includes a heater 1, a control thermometer 2, a furnace core tube 3, a furnace core tube support member 4 for supporting the furnace core tube, a furnace core tube support base 5, a heat insulating material 6, and an upper heat insulating material 7. The furnace core tube end heat insulating material 8 and the housing 9 are constituted.
A heat insulating material 6 is provided on the inner bottom wall and side wall portion of the housing 9, and an upper heat insulating material 7 is provided on the ceiling portion to form a furnace body wall. The heat insulating material is selected from materials that can withstand up to 1600 ° C., for example, ceramic fiber is suitable.

The heater 1 has a U-shaped shape as shown in FIG. 1 and is provided on both sides of the furnace core tube 3 as shown in FIG. 2. As the material, for example, MoSi ₂ is used.
A plurality of control thermometers 2 are provided immediately above the furnace core tube 3 with an appropriate interval in the longitudinal direction. For example, a JIS symbol “B” type thermocouple is used.

A furnace core tube 3 made of alumina is disposed inside the high temperature heat treatment furnace surrounded by the heat insulating material 6 and the upper heat insulating material 7. In the present embodiment, the furnace core tube 3 is made of alumina. However, the present invention is not limited to this, and needless to say, the furnace core tube 3 may be formed of ceramics or a heat-resistant metal.
The furnace core tube 3 made of alumina is supported by a furnace core tube support 5 via an alumina core tube support member 4 made of alumina. First, the furnace core tube support member 4 serves to prevent the furnace core tube 3 and the furnace core tube support 5 from reacting in a high temperature state in preparation for replacement of the furnace core tube 3. Any material that does not easily react with atmospheric gas in a high temperature atmosphere may be used, and the material is not limited to alumina.
Second, the furnace core tube support member 4 is formed by forming a central portion of a material having a high thermal conductivity and both ends of a material having a low thermal conductivity in the longitudinal direction thereof. Heat escape from both end portions can be prevented to lengthen the soaking portions at both ends of the furnace core tube, and further improvement in the soaking capability in the longitudinal direction of the center portion of the furnace core tube can be achieved.
In this case, for example, silicon carbide (SiC) or aluminum nitride (AlN) is used as the material having a high thermal conductivity at the center of the furnace core tube support member 4, and titanium is used as a material having a low thermal conductivity at both ends. Aluminum acid (Al ₂ O ₃ .TiO ₂ ) is desirable, but it is not particularly limited to these.
Moreover, the cross-sectional shape of the furnace core tube support member 4 may be a circular shape or a square shape in addition to the semicircular shape shown in FIG. When the furnace core tube support member 4 having a circular cross section is used, a uniform high temperature region is formed around the furnace core tube, so that it is possible to improve the heat uniformity of the furnace core tube.

The furnace core tube support 5 is formed of a material that has good heat insulation and is difficult to deform in a high temperature range. In FIG. 2, a indicates the height from the heat insulating material 6 at the lower part of the furnace core tube support 5, and b indicates the thickness of the furnace core tube support 5. By making a sufficiently larger than b, the temperature distribution in the vertical direction of the furnace core tube 3 can be improved.
In the present embodiment, the furnace core tube support 5 has a semicircular shape whose upper end is along the outer surface of the furnace core tube support member 4, and its lower portion is a groove in the lower heat insulating material 6. Is fitted.

  In order to cope with changes in the height a of the furnace core tube support 5 due to thermal expansion and compression of the furnace core tube support 5, the furnace tube end heat insulating material 8 that supports both ends of the furnace core 3 is a furnace body. Separate from the side insulation 6. As shown in FIG. 1, by providing a space above and below the furnace core tube end heat insulating material 8, stress on the furnace core tube 3 due to a change in the height a of the furnace core tube support 5 can be prevented.

  As shown in FIG. 1, a plurality of plate-like upper heat insulating materials 7 are arranged in a horizontal row on the upper portion of the furnace wall to form a ceiling of the furnace wall. As shown in FIG. 2, each plate-like upper heat insulating material 7 has a side surface processed into a staircase shape, and the U-shaped heater 1 is connected to the furnace core tube 3 for each plate-like upper heat insulating material 7. Two are supported so as to be sandwiched from both sides. When the heater 1 fails, only the plate-like upper heat insulating material 7 that supports the failed heater 1 can be taken out, and the heater replacement work can be made more efficient.

The apparatus shown in FIGS. 1 and 2 was fabricated and operated at temperatures up to 1600 ° C. Further, as an example of data indicating temperature uniformity, a temperature distribution in the furnace at 1100 ° C. was measured.
FIG. 3 is a diagram comparing the temperature distribution in the furnace core tube between the high-temperature heat treatment furnace of the present invention and a conventional heat treatment furnace. A dotted line A represents the temperature distribution of the conventional heat treatment furnace, and a solid line B represents the present invention. The high-temperature heat treatment furnace temperature distribution is shown. In a conventional high-temperature heat treatment furnace having a local support, the temperature uniformity at 1100 ° C. is ± 6 ° C. in the range of the center of the furnace core tube ± 50 cm, but in a high-temperature heat treatment furnace produced using the present invention, 1100 The temperature uniformity at ° C. became ± 1 ° C. or less in the range of the center of the furnace core tube ± 50 cm.
Further, as a result of use at 1600 ° C. for 100 hours, no distortion occurred in the furnace core tube.

  The thermocouple produced using the high-temperature heat treatment furnace of the present invention has high homogeneity that could not be achieved conventionally. Homogeneity is the most important factor in determining the accuracy of thermocouples, and with the advent of the device of the present invention, it has become possible to produce thermocouples with high accuracy for the first time.

It is side surface sectional drawing which shows schematically the high temperature heat processing furnace which concerns on embodiment of this invention. It is the alpha-alpha sectional view taken on the line of FIG. It is the figure which compared the temperature distribution in the furnace core pipe of the high temperature heat processing furnace which concerns on embodiment of this invention, and the conventional heat processing furnace.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heater 2 Thermometer for control 3 Furnace core tube 4 Furnace core tube support member for furnace core tube support 5 Furnace core tube support stand 6 Heat insulating material 7 Upper heat insulating material 8 Furnace core tube end heat insulating material 9 Case

Claims (5)

  A high-temperature heat treatment furnace provided with a straight cylindrical furnace core tube made of a heat-resistant material and a heating means for accommodating and heating the furnace core pipe, the wall of the furnace body being thermally insulated with a heat insulating material. A high-temperature heat treatment furnace characterized in that a region located inside the heat treatment furnace of the furnace core tube is continuously supported by a heat insulating furnace core tube support.   2. The high-temperature heat treatment furnace according to claim 1, wherein a furnace core tube support member for supporting the furnace core tube is disposed between the furnace core tube and the furnace core tube support.   3. A high-temperature heat treatment furnace according to claim 1, wherein, in the longitudinal direction of the furnace core tube support member, a central portion is formed of a material having high thermal conductivity and both end portions are formed of a material having low thermal conductivity. .   A plurality of plate-like upper heat insulating materials are arranged in the longitudinal direction of the furnace core tube on the upper inner wall of the furnace body, and a U-shaped heater is attached to each plate-like upper heat insulating material. The high-temperature heat treatment furnace according to claim 3. The furnace core tube end heat insulating material that supports both ends of the furnace core tube is separated from the heat insulating material on the wall of the furnace body, and spaces are provided above and below the furnace core tube end heat insulating material. The high-temperature heat treatment furnace according to any one of the above.

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