JPH0452217A - vacuum furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum furnace used for subjecting various materials to heat treatment such as quenching, tempering, sintering, and firing.

[Prior Art] In this type of furnace, a heater is disposed, for example, in a vacuum container near a space in which a material to be treated is placed, and the material to be treated is heated by heat from the heater.

[Problems to be Solved by the Invention] In such conventional vacuum furnaces, the temperature of the material to be processed is high in areas that are close to the heater and receive a lot of heat directly from it; There is a problem in that the temperature is relatively low in locations where a small amount of heat is received, resulting in temperature differences at various locations on the material to be treated.

The present invention was made to solve the problem (technical plan H) of the prior art described above, and in places where the material to be treated receives a small amount of heat directly from the heater, the heat reflected by the reflector is used. It is an object of the present invention to provide a vacuum furnace that can compensate for the temperature distribution of the entire material to be processed.

[Means for Solving the Problems] In order to achieve the above object, the vacuum furnace of the present invention has a heat insulating wall surrounding the periphery of the storage space in a vacuum container having a storage space for the material to be treated inside. In a vacuum furnace that is provided with a heater for heating the material to be processed that is placed in the holding space inside the heat insulating wall, the amount of heat directly received from the heater in the holding space is A reflector made of a material with a low emissivity is attached to the outer surface, inner surface, or both surfaces of the heat insulating wall in the portion facing the area where there is little radiation.

[Operation] Heat is applied to the material to be treated by the heat generated by the heater. In this case, a portion of the material to be treated that receives a large amount of direct heat from the heater is sufficiently heated by the heat. On the other hand, the portions that receive a small amount of direct heat receive not only the heat from the heater but also the heat reflected by the reflector, and these portions are also sufficiently heated. As a result, the entire material to be treated is heated to have a uniform temperature distribution.

[Example] The drawings showing the embodiments of the present application will be described below.

In FIG. 1, 1 indicates a vacuum furnace. 2 is a vacuum container,
It consists of a main body 3 and a door 4 provided at the entrance/exit of the main body 3. 5 is a heat insulating wall installed at the main body 6 and the entrance to the main body 6! #7, and the space inside thereof serves as a heat treatment chamber 8. Reference numeral 10 denotes a mounting table provided in the heat treatment chamber 8, and the space above it serves as a storage space 11 for the material to be treated. Reference numeral 12 denotes a heater disposed around the storage space 11, which is attached to a heat insulating wall. Next, 13 shown in FIG. 2 is a reflector, which is a plate made of a material with low emissivity.
For example, a polished stainless steel plate (thickness, for example, 1.60 mm) is used (another low emissivity material is molybdenum, for example), and is attached to the outer surface of the heat insulating wall 5 at 117. For example, the attached state is as shown in the figure.
This reflector 1 is sandwiched between a heat insulating wall 5 and a well-known frame 14 that supports it (it may also be attached to the door 7).
3 is attached to a heat insulating wall in a portion of the storage space 11 that faces a portion where the amount of direct heat received from the heater 12 is small, for example, a heat insulating wall on the side where the heater 12 is not provided as shown in the figure. . The attached surface may be an inner surface or both inner and outer surfaces in addition to the outer surface as in this example. Next, reference numeral 15 indicates a well-known cooling structure for a material to be treated, which will be explained below. 16 is a cooler, and 17 is a cooling fan, which is driven by a fan motor 18. 19 is a motor cover for maintaining vacuum. 20.21
22 and 23 are current plates, respectively, and dampers for upstream and downstream switching. In such a cooling structure 15, the damper 2
By operating the cooler 16 and fan 17 in the state shown in FIG. 2.23, the cooling gas circulates along the path shown by the solid arrow, and the material to be processed placed in the storage space 11 is cooled. By switching the dampers 22 and 23, the material to be processed can also be cooled by flowing the cooling gas from the bottom to the top in the holding space 11.

Next, heat treatment of a material to be treated using the above-mentioned vacuum furnace will be explained.

, the doors 4 and 7 are opened, and the material to be processed 31 is placed on the mounting table 10. The placed state is such that large objects 31 are left as they are, and small objects 31 are stacked on a shelf, for example. Next, the door 4.7 is closed, the inside of the vacuum container 2 is evacuated, the heater 12 is energized to generate heat, and the material to be processed 31 is heated mainly by radiation heat transfer from the heater 12.

In the case of the above-mentioned heating, the portion of the material to be treated 31 directly facing the heater 12 receives a large amount of heat directly from the heater 12 and is sufficiently heated. On the other hand, a portion not directly facing the heater 12, for example, the side of the door 7, receives a small amount of heat directly from the heater 12. However, on that side, the reflector 13 reflects the heat that attempts to escape to the outside of the heat insulating wall 5 to the side of the heat insulating wall 5. As a result, the temperature of the heat insulating wall 5 in that part is kept sufficiently high, and heat loss by the heat insulating wall 5 is prevented. In this way, the presence of the reflector 13 improves the temperature distribution within the effective dimensions of the heat treatment chamber 8;
The treated material 31 is heated with uniform temperature distribution throughout.

Once the material to be processed 31 has been heated to a predetermined level as described above, the power supply to the heater is stopped, cooling gas is introduced into the vacuum container 2, and the cooler 16 and fan 17 are activated as described above. The processing target material 31 is cooled.

When the cooling is finished, the door 4.7 is opened and the processed material 31 that has undergone heat treatment is taken out.

When the temperature distribution width during heating was actually measured when the reflector 13 as described above was not used and when it was used, it was found that
When not used, the temperature was 10°C, but when it was used, the temperature improved to 5.5°C.

Next, FIG. 2 shows a different embodiment of the present application, and shows an example in which a heat removal element is provided in an internal space surrounded by a heat insulating wall 5e. In the figure, reference numeral 21 denotes a transport roll for transporting the material to be processed 31e in a direction perpendicular to the plane of the paper, and is rotated by a rotation device provided outside the vacuum container 2e. There is. The roll 21 has a well-known water-cooled structure so as to be able to withstand the high heat of the space inside the heat insulating wall 5e, and is shown as an example of the above-mentioned heat extraction element. The roll 21 has an annular receiving member 22 made of graphite, for example, for receiving the material to be treated, and the other part 23 is covered with a heat insulating material and the outside is covered with a low emissivity material as described above. It is covered with a plate-shaped reflector made of material.

With such a configuration, when the material to be treated 31e is heated, the reflector prevents the roll 21, which is the heat extraction element, from removing heat from the material to be treated 31e, and as a result, the material to be treated is heated. uniform heating is possible.

It should be noted that parts that are considered to have the same or equivalent structure as those in the previous figure in terms of function are given the same reference numerals as in the previous figure with the letter e, and redundant explanations are omitted.

[Effects of the Invention] As described above, according to the present invention, the material to be treated 31 can of course be heated by the heat generated by the heater 12, and in the case of heating, the material to be treated 31 is directly heated by the heater 12. The portions receiving a large amount of heat can be sufficiently heated by the heat, while the portions receiving a small amount of heat directly can be heated by the heater 12.
In addition to the heat from the reflector 13, the heat reflected by the reflector 13 can be received, and that part can be sufficiently heated, and the entire object to be treated 31 can be heated with a uniform temperature distribution. There is.

Moreover, since the reflector 13 merely reflects heat, it can be attached to a movable part such as the door 7, giving it flexibility in its use.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application; FIG. 1 is a longitudinal sectional view of a vacuum furnace, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a longitudinal sectional view showing a different embodiment. 2...Vacuum container, 5...Insulating wall, 11. Storage space,
12... Heater, 13... Reflector. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. In a vacuum container having a storage space for a material to be treated inside, a heat insulating wall surrounding the storage space is provided,
Inside the heat insulating wall, in a vacuum furnace equipped with a heater for heating the material to be processed left in the holding space, a portion of the holding space where the amount of direct heat received from the heater is small. A vacuum furnace characterized in that a reflector made of a material with a low emissivity is attached to the outer surface, inner surface, or both surfaces of the heat insulating wall in a portion facing the wall. 2. In a vacuum container having a storage space for the material to be treated inside, a heat insulating wall surrounding the storage space is provided,
Inside the heat insulating wall, the vacuum furnace is equipped with a heater and a heat extraction element for heating the workpiece placed in the storage space, and the heat extraction element is made of a material with a low emissivity. A vacuum furnace characterized by being surrounded by a reflector to prevent heat loss.