JPH0434399Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial Application Field" This invention relates to a heat treatment furnace such as a sintering furnace or a degreasing furnace for sintering ceramics, metal powder, etc.

``Prior art'' In this type of heat treatment furnace, it is important to sufficiently remove impurity gas such as wax generated from the workpiece during sintering and degreasing from the furnace to improve the quality of the sintered product and the furnace performance. This is extremely important for maintenance management. That is,
If these gases are not sufficiently removed, they will cool down on the inner wall of the heating chamber or furnace body, liquefy or solidify, and adhere to the inner wall of the heating chamber or furnace, and during the next process, they may re-evaporate and contaminate the object to be processed. A problem arises in that the time required for evacuation becomes longer.

For this reason, a heat treatment furnace as shown in FIG. 2 has been proposed. This heat treatment furnace has a heating chamber 2 inside a furnace body 1 that can maintain a vacuum with a heat insulating material.
The inner case 3 is further provided inside the inner case 3. The workpiece 5 charged into the inner case 3 is indirectly heated by a heater 4 disposed around the inner case 3 to perform heat treatment such as sintering or degreasing. In this heat treatment furnace, heating chamber 2
There are gaps 8 and 8 between the main body of the inner case 3 and its lid 6, and between the main body of the inner case 3 and its lid 7, respectively.
9, and the carrier gas blown into the furnace body 1 through the carrier gas introduction pipe 10 is introduced into the inner case 3 through the gaps 8 and 9, as shown by the arrow in the figure. ing. Along with the carrier gas, impurity gas generated during processing is sucked through the exhaust port 12 through the exhaust pipe 11, so that the gas is directly exhausted from the inner case 3.

Note that the lid 6 of the heating chamber 2 and the lid 7 of the inner case 3 are integrated, and are connected to the furnace lid 13 of the furnace body 1 by a connecting member 14.

``Problems to be solved by the invention'' However, in the heat treatment furnace described above, although the gas near the outlet 12 is sucked, the gas diffused far from the outlet 12 cannot be sufficiently sucked. Therefore, the gas from inside the inner case 3 is not always sufficiently discharged. There was a fear that the gas that was not discharged would flow into the heating chamber 2 and the furnace body 1 through the gaps 9 and 8, which were provided as carrier gas flow paths.

This invention was made in view of the above circumstances, and the purpose is to provide a heat treatment furnace that can reliably remove impurity gas from inside the inner case.

``Means for solving the problem'' This idea has a heating chamber inside a furnace body that can maintain a vacuum, and an inner case inside the heating chamber to reduce the amount of heat generated by the material to be processed. In a heat treatment furnace configured to directly discharge gas from inside the inner case, the inner case is composed of an inner wall body and an outer wall body facing each other with a predetermined distance apart, and there is a space between them. A hollow portion is formed, and the inner wall body is provided with a number of gas flow ports that guide the gas to the hollow portion, while the gas guided to the hollow portion is discharged to the outside of the furnace body. The present invention is characterized in that a gas exhaust pipe is provided with its tip facing the hollow portion and passing through the heating chamber and the furnace body.

``Function'' In the heat treatment furnace of this invention, the hollow part of the inner case serves as a gas flow path, and impurity gases generated during processing are passed through the hollow part through the numerous flow holes provided in the inner wall. The gas is guided through the hollow part and discharged to the outside of the furnace body through a gas discharge pipe.

"Embodiment" Hereinafter, an embodiment of this invention will be described with reference to FIG. In the heat treatment furnace of this embodiment, the same components as those in the conventional heat treatment furnace described above are designated by the same reference numerals in FIG. 1 as in FIG.
A detailed explanation thereof will be omitted.

This heat treatment furnace, like the conventional heat treatment furnace,
A heating chamber 2 is disposed within a furnace body 1, and an inner case 20 is disposed inside the heating chamber 2.

This inner case 20 includes an external wall body 21,
It is composed of an inner wall body 23 fixed to the inside of the outer wall body 21 by fixing members 22...
They face each other with a predetermined distance apart, and a hollow portion 24 is formed between them. That is, this inner case 20 has a double wall structure, and a hollow portion 24 inside the double wall serves as a gas flow path. It is desirable that the distance between the outer wall body 21 and the inner wall body 23 be set in consideration of gas flow rate and flow resistance.

The outer wall 21 and the inner wall 23 are provided with an outer cover 25 and an inner cover 26, respectively, and are connected and fixed to each other by connecting members 27, 27. Then, the outer cover 25 and the inner cover 2 are connected.
6 is connected to the lid 6 of the heating chamber 2, so that by opening and closing the furnace lid 13 of the furnace body 1, the lid 6 of the heating chamber 2, the outer lid 25 of the inner case 20, and the inner The lid 26 can be opened and closed at the same time.

Further, in the inner wall body 23 and its inner cover 26, a large number of gas flow holes 28 communicating between the inside of the inner wall body 23 and the hollow portion 24 are provided on each wall surface of the inner wall body 23 and the inner cover 26. They are provided almost evenly over the entirety of 26. These gas flow ports 28...
is for guiding impurity gas generated from the object to be processed 5 during heat treatment to the hollow portion 24.

Further, a carrier gas inlet 29 is provided in the inner wall 23 of the inner case 20, and a carrier gas inlet pipe 30 is connected to this carrier gas inlet 29. Further, the external wall body 21 is provided with a gas exhaust port 31 , the tip of which faces the hollow portion 24 and which passes through the heating chamber 2 and the furnace body 1 . A tube 32 is connected. The carrier gas introduction pipe 30 is for directly introducing carrier gas into the inner case 20 (inside the inner wall body 23) from a supply source (not shown), and the gas exhaust pipe 32 is for introducing carrier gas directly into the inner case 20 (inside the inner wall body 23), and the gas exhaust pipe 32 is for introducing carrier gas directly into the inner case 20 (inside the inner wall body 23) from a supply source (not shown). The impurity gas guided into the hollow part 24 is sucked together with the carrier gas,
It is for discharging to the outside of the furnace body 1.

The configuration of this heat treatment furnace has been explained above, and now how to use it will be explained. First, the workpiece 5 is charged into the inner case 20, and the furnace lid 1 of the furnace body 1 is
3. Close the lid 6 of the heating chamber 2, the outer lid 25, and the inner lid 26 of the inner case 20, and make the inside vacuum. Then, the object to be processed 5 is heated by the heater 4 .
When the workpiece 5 is heated to about 400 to 500°C, the wax (impurities) evaporates from the workpiece 5 and the gas is dissipated into the inner case 20. At that point, the carrier gas is introduced into the gas introduction pipe 30. Therefore, the carrier gas is introduced into the inner case 20 and is driven to a vacuum evacuation device (not shown). This allows the gas, along with the carrier gas, to
As shown by the arrows in the figure, the gas is sucked into the hollow part 24 from the gas distribution port 28 and flows out.
The gas flows inside toward the gas discharge port 31, and the discharge pipe 32
is discharged outside the furnace body 1.

As mentioned above, according to this heat treatment furnace,
A flow port 28 provided throughout the inner wall body 23 allows impurity gas generated from the object 5 to be processed to flow through the flow port 28
Since the gas is sucked from ..., the gas can be discharged evenly from each position inside the inner case 20, and the gas diffused throughout the inner case 20 can be completely discharged.

Furthermore, in this heat treatment furnace, even if gas flows out from the gap between the inner wall body 23 and its inner cover 26, the gas enters the hollow part 24 and is sucked and discharged from there. To the outside of the body 21,
That is, it does not flow into the heating chamber 2 or the furnace body 1.

Further, in this heat treatment furnace, a carrier gas is not necessarily used because exhaust gas can be sufficiently uniformly exhausted. Therefore, it is possible to perform sufficient evacuation while maintaining a high degree of vacuum without introducing carrier gas.

The installation position and size of each gas flow port 28 may be changed as appropriate by taking into consideration gas flow resistance, etc. For example, the number of gas flow ports 28 may be increased as the position is farther from the gas discharge port 31. Alternatively, if the diameter of the gas flow port 28 provided near the gas discharge port 31 is made smaller than that of the gas flow port 28 provided at a farther position, more uniform discharge can be achieved.

Furthermore, in the heat treatment furnace of this invention, the gas can be sufficiently discharged without using carrier gas, so the introduction pipe 30 for introducing carrier gas may be omitted.

"Effect of the invention" As explained in detail above, according to this invention, the inner case is composed of an outer wall and an inner wall, and a hollow part is provided between them, and gas is discharged from the hollow part. Because of this structure, the impurity gas generated during heat treatment can be discharged evenly from each position within the inner case, and the gas can be completely discharged without leaking to the outside of the inner case. It has the effect of being able to do it.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a schematic configuration of a heat treatment furnace of this embodiment, and FIG. 2 is a side sectional view showing a schematic configuration of a conventional heat treatment furnace. 1...furnace body, 2...heating chamber, 5...workpiece,
20... Inner case, 21... External wall, 2
3...Inner wall body, 24...Hollow part, 28...Gas distribution port, 32...Gas exhaust pipe.

Claims (1)

[Scope of utility model registration request] A heating chamber is provided inside a furnace body that can maintain a vacuum, and an inner case is provided inside the heating chamber, so that the gas generated from the object to be processed is directly discharged from inside the inner case. In the heat treatment furnace configured as shown in FIG. A large number of gas flow ports are provided to guide the gas into the hollow part, and a gas exhaust pipe for discharging the gas led into the hollow part to the outside of the furnace body has its tip connected to the hollow part. A heat treatment furnace, characterized in that it is provided in such a way that it faces the heating chamber and passes through the heating chamber and the furnace body.