JP4310457B2 - Heat treatment furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat treatment furnace.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a typical heat treatment furnace used for firing ceramic materials or the like is shown in FIG. The heat treatment furnace 20 includes a heat treatment furnace main body 21, and the heat treatment furnace main body 21 includes a heat treatment zone 22 that accommodates an object to be heat treated (hereinafter referred to as a workpiece), a heater (heating means) 23, a hearth 24, have. The heat treatment furnace main body 21 has an opening 21a in the lower part thereof, and the hearth 24 enters and exits the opening 21a. A heat insulating material 28 is provided inside the heat treatment furnace main body 21. The hearth 24 is made of a heat insulating material, mounts a trough 29 containing workpieces, and seals the heat treatment zone 22 when it is raised and positioned in the opening 21 a at the lower part of the heat treatment furnace body 21. The heater 23 is provided in the heat treatment zone 22 and heats the workpiece.
[0003]
Further, the heat treatment furnace 20 includes a driving unit 25 and a frame 27. The drive means 25 rotates and moves the hearth 24 up and down, is accommodated in the frame 27, and is provided in the lower part of the heat treatment furnace body 21. In addition, as the drive means 25, there exists what performs a rotational drive and a raising / lowering drive by a separate mechanism (refer patent document 1).
[0004]
In the heat treatment furnace 20 as described above, the work is heated by the heater 23 while the hearth 24 is rotated by the driving means 25. At this time, no matter how the hearth 24 is made of a heat insulating material, the radiant heat from the heat treatment zone 22 is transmitted to the space below the hearth 24 through the hearth 24. Further, the radiant heat from the heat treatment zone 22 is transmitted to the lower space of the hearth 24 through the gap between the heat treatment furnace main body 21 and the hearth 24. Since the drive means 25 provided below the hearth 24 is exposed to a high temperature due to the high-temperature radiant heat from the heat treatment zone 22, various adverse effects occur, so the high-temperature radiant heat from the heat treatment zone 22 is applied to the drive means 25. It is necessary not to be transmitted.
[0005]
Although the radiant heat is weakened if the distance from the heat source is increased, there is a limit to the distance that can be taken from the driving means 25 to the hearth 24 because of spatial restrictions. Therefore, cooling air is supplied by an air supply means (not shown) to suppress radiant heat from the heat treatment zone 22 transmitted to the drive means 25.
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 6-88682
[Problems to be solved by the invention]
However, the conventional heat treatment furnace 20 has the following problems.
1. In order to suppress the radiant heat from the hearth 24, if the cooling air is supplied directly to the lower surface of the hearth 24, the radiant heat can be efficiently suppressed, but the upper surface of the hearth 24 facing the heat treatment zone 22 is cooled. The difference with the lower surface of the hearth 24 becomes large, and the temperature gradient in the hearth 24 becomes steep. For this reason, the amount of heat released from the hearth 24 is increased, and the power supplied to the heater 23 must be increased in order to maintain the heat treatment zone at a desired temperature, which is costly.
2. When cooling air convection is generated below the hearth 24 to cool the radiant heat from the hearth 24, the amount of heat released from the hearth 24 can be suppressed, but the surface temperature of the hearth lower surface 24. When the difference from the allowable temperature transmitted to the driving means 25 is large, the amount of radiant heat corresponding to the temperature difference must be dissipated only by the convection of the cooling air, so that a large amount of cooling air is required.
[0008]
The object of the present invention is to suppress the radiant heat to the drive means to a desired temperature with a smaller amount of air even when the surface temperature of the bottom surface of the hearth is high, and to suppress the heat radiation from the hearth to a low level. An object of the present invention is to provide a heat treatment furnace that can be used.
[0009]
[Means for Solving the Problems]
The heat treatment furnace of the first invention of the present application is a heat treatment furnace main body having a heat treatment zone for containing the heat treatment object, a heating means for heating the heat treatment object, a hearth provided at a lower portion of the heat treatment furnace body, A heat treatment furnace comprising a driving means for driving the hearth, wherein a plurality of reflecting plates are provided between the hearth and the driving means in a direction substantially parallel to the hearth, and between the plurality of reflecting plates. An air supply means for supplying cooling air is provided.
[0010]
With such a configuration, the reflection plate can block the radiant heat from the hearth toward the drive means, and the heat reflection of the reflection plate suppresses the temperature drop on the bottom surface of the hearth, thereby reducing the heat radiation from the hearth. Can be suppressed.
[0011]
Further, by supplying the cooling air between the plurality of reflecting plates, the reflecting plate can be directly cooled, the flow of the cooling air layer can be secured, and the dissipation of the cooling air can be prevented. Thereby, the thermal conductivity of the cooling air layer is increased and the radiant heat from the reflecting plate can be efficiently dissipated, so that the amount of cooling air necessary for cooling the reflecting plate can be reduced.
[0012]
In addition, by adjusting the amount of cooling air to be supplied, the surface temperature of the reflector below the cooling air can be maintained at a desired temperature.
[0013]
Further, by limiting the cooling air supply path to the space between the plurality of reflectors, it is possible to suppress the scattering of dust on the sliding surface of the driving means by the cooling air.
[0014]
Further, in the heat treatment furnace according to the second aspect of the present invention, the cooling air from the air supply means is secondly applied to the reflecting plate provided at a position closest to the driving means among the plurality of reflecting plates, and to the driving means. It is preferable to be supplied between the reflector and the reflector provided at a position close to.
[0015]
With such a configuration, radiant heat can be suppressed to a desired temperature with less cooling air. Further, since the cooling air is supplied at a location close to the driving means, that is, a location far from the hearth, the hearth is not easily affected by the cooling air, and heat radiation from the hearth to the bottom of the hearth can be further suppressed. .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described.
The material and shape of the heat treatment furnace main body used in the present invention are not particularly limited as long as it has a heat treatment zone inside thereof and an opening below the heat treatment zone. Further, a heat insulating material is disposed inside the heat treatment zone, and the heat insulating material is not particularly limited, and specific examples include heat-resistant bricks and ceramic fiber boards.
[0017]
The heating means is not particularly limited as long as it can perform heat treatment at a desired temperature, but it is preferable to use an appropriate heater according to the heating temperature. For example, if heat treatment is performed at a relatively high temperature, a heater made of SiC or the like is used. If heat treatment is performed at a relatively low temperature, a heater made of iron-chromium alloy or nickel-chromium alloy is used. Use.
[0018]
Moreover, it is preferable to provide the said hearth so that the clearance gap between the said heat processing furnace main bodies may be opened as much as possible, in order to improve the sealing performance of a heat processing zone.
[0019]
Moreover, the said drive means will not be specifically limited if it can rotate and raise / lower a hearth. Specifically, there is a motor that uses a motor as a drive source and converts the rotational drive of the motor into a desired drive direction by a linear guide and transmits it to the hearth.
[0020]
The reflector is not particularly limited as long as it is provided at the lower part of the hearth and can reflect the radiant heat from the hearth, but in order to reflect the radiant heat from the hearth efficiently, the shape of the reflector is not limited. And the area is preferably substantially the same as the bottom of the hearth. The material of the reflector is preferably a metal such as stainless steel having a smooth surface and heat resistance. The number of reflectors is not particularly limited as long as it is two or more. The distance between the reflecting plate and the reflecting plate is not limited as long as it can supply cooling air, but is preferably 20 mm to 40 mm.
[0021]
The air supply means is not particularly limited in configuration and arrangement as long as it can continuously supply cooling air between the reflection plate and the reflection plate.
[0022]
Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to such examples.
[0023]
【Example】
A heat treatment furnace according to an embodiment of the present invention will be described. FIG. 1 is a schematic sectional view of a heat treatment furnace of the present invention.
[0024]
As shown in FIG. 1, the heat treatment furnace 1 of the present invention includes a heat treatment furnace body 3, a heater (heating means) 5, a hearth 7, a drive means 9, a reflector 11, an air supply means 13, It consists of a frame 18.
[0025]
More specifically, the heat treatment furnace body 3 is made of a lightweight heat insulating material, has a heat treatment zone 4, and has a hearth 7, a drive means 9, a reflector 11, and an air supply means 13. ing. A heat insulating material 17 is provided around the heat treatment zone 4. In addition, an opening 3 a through which the hearth 7 enters and exits is provided in the lower part of the heat treatment zone 4.
[0026]
The heater 5 is a bar heater made of SiC, and is provided inside the heat treatment furnace body 3 so as to surround the heat treatment zone 4.
[0027]
The hearth 7 is made of the same lightweight heat insulating material as the heat treatment furnace main body 3 and is provided at the lower part of the heat treatment furnace main body 3, and has a different diameter according to the shape of the opening 3 a provided at the lower part of the heat treatment furnace main body 3. It is shaped like two stacked cylinders. In addition, on the upper surface of the hearth 7, a mounting table 7 a for mounting the rod 15 is provided.
[0028]
The drive means 9 is provided below the hearth 7 and includes a drive mechanism 9a for rotating and raising and lowering the hearth 7, and a support 9b that supports the hearth 7 and transmits a driving force from the drive mechanism 9a. The support column 9b is made of SUS304, and has one end portion fixed to the drive mechanism 9a and the other end portion fixed to the bottom surface of the hearth 7. A plurality of support columns 9b are provided concentrically from the center of rotation of the hearth 7. In addition, the number of the support | pillars 9b is not specifically limited.
[0029]
The reflector 11 is made of SUS304, and the diameter thereof is the same as the diameter of the bottom of the hearth 7. Two reflectors 11 are provided between the hearth 7 and the driving means 9 and are fixed to the support column 9 b so as to be parallel to the hearth 7. The distance between the reflecting plate 11 and the reflecting plate 11 is 20 mm.
[0030]
The air supply means 13 includes a supply mechanism 13 a that ejects cooling air and a supply nozzle 13 b that defines the supply direction of the cooling air, and is disposed in the heat treatment furnace body 3. The supply port 13 b is provided so that cooling air can be supplied between the reflection plate 11 and the reflection plate 11. In the heat treatment furnace 1 of this embodiment, the temperature of the hearth 7 is 120 ° C., and the temperature of the driving means 9 needs to be maintained at 50 ° C. or less. At this time, the amount of cooling air supplied from the air supply means 13 is 240 m ³ per hour.
[0031]
The frame 18 is made of a general structural rolled steel and has a rectangular parallelepiped shape having a storage space inside. Further, it is located below the heat treatment furnace body 3. In addition, the drive means 9 and the air supply means 13 are accommodated inside the frame 18. Further, a cooling air discharge port 18 a is provided on an extension of the cooling air supply direction 19 sent from the air supply means 13 at a location on the frame 18.
[0032]
Here, suppression of radiant heat in the heat treatment furnace 1 of the present invention will be described.
In the heat treatment furnace 1, the radiant heat conducted from the hearth 7 toward the driving means 9 is reflected by the reflector 11 disposed on the hearth 7 side of the two reflectors 11 as suppression of radiant heat in the first stage. A part of the light is reflected toward the hearth 7.
[0033]
Next, as suppression of radiant heat in the second stage, the radiant heat is cooled by a cooling air layer flowing between the reflector 11 on the hearth 7 side and the reflector 11 on the drive means 9 side. At this time, by passing the cooling air between the two reflecting plates 11, the cooling air is prevented from being diffused unnecessarily, and the amount of cooling air to be supplied is reduced. Further, by preventing the cooling air from directly hitting the hearth 7, the hearth 7 is prevented from being cooled more than necessary.
[0034]
Furthermore, as suppression of the radiant heat in the third stage, the radiant heat that has not been dissipated by the cooling air layer is reflected toward the hearth 7 by the reflector 11 on the drive means 9 side.
[0035]
As described above, by suppressing the radiant heat from the hearth 7 over three stages, the radiant heat conducted to the driving means 9 is sufficiently suppressed.
[0036]
【The invention's effect】
If the heat treatment furnace of the present invention is used, even if the surface temperature of the hearth is high, the radiant heat to the driving means can be suppressed to a desired temperature with a smaller amount of air, and the heat radiation from the hearth is kept low. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a heat treatment furnace according to an embodiment of the present invention.
FIG. 2 is a schematic sectional view of a conventional heat treatment furnace.
[Explanation of symbols]
1 Heat treatment furnace 3 Heat treatment furnace body 5 Heater (heating means)
7 hearth 9 drive means 11 reflector 13 air supply means

Claims (2)

A heat treatment furnace main body having a heat treatment zone for containing the heat treatment object, a heating means for heating the heat treatment object, a hearth provided at a lower portion of the heat treatment furnace main body, and a driving means for driving the hearth. A heat treatment furnace,
A plurality of reflecting plates are provided between the hearth and the driving means in a direction substantially parallel to the hearth, and air supply means for supplying cooling air is provided between the plurality of reflecting plates. Heat treatment furnace. The cooling air from the air supply means is between a reflector provided at a position closest to the drive means among a plurality of reflectors and a reflector provided at a position closest to the drive means. The heat treatment furnace according to claim 1, wherein cooling air is supplied.

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