JPH06136406A - Baking method and device for vacuum furnace - Google Patents

Abstract

PURPOSE:To sufficiently bake the inner peripheral surface of a water cooled furnace shell and to effectively remove the deposits therefrom by discharging the cooling water of the water cooled furnace shell, then energizing heaters disposed between the water cooled furnace shell and the heat insulating material of a treatment chamber within the shell. CONSTITUTION:The treatment chamber 22 enclosed by the heat insulating material 21 is formed within the water cooled furnace shell 11 of a vacuum furnace. Moldings, etc., are disposed on a placing table 26 in the treatment chamber 22 and are subjected to a treatment, such as sintering, in a vacuum by the heaters 23 to 25 for treatment. An automatic valve 31 is operated by a controller 61 to discharge the cooling water from the hollow part 14 of the water cooled furnace shell 11 after the end of the treatment. The sheathed heaters 41 for baking mounted between the water cooled furnace shell 11 and the heat insulating material 21 are then energized via a power source 51. As a result, the inner peripheral surface of the water cooled furnace shell 11 is sufficiently baked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum furnace baking method and apparatus. For example, a vacuum furnace is used when a metal powder is kneaded together with a binder or the like to be molded and the molded product is sintered. The vacuum furnace generally has a processing chamber surrounded by a heat insulating material formed in a furnace shell, and a processing heater is mounted in the processing chamber.

By the way, when the vacuum furnace is repeatedly operated, scattered binders and fragments of the constituent materials in the furnace adhere to the inner and outer peripheral surfaces of the heat insulating material, and further to the inner peripheral surface of the furnace shell, and gradually. accumulate. If these deposits are left as they are, the deposits absorb moisture in the air and disturb the vacuum atmosphere in the furnace, and the deposits are conversely scattered to the treated product to color the treated product. Become. Therefore, in the operation of the vacuum furnace, the inside of the furnace is baked, for example, periodically to remove the above deposits. The present invention relates to an improvement of a baking method and apparatus for a vacuum furnace, which is provided with a water-cooled furnace shell, among vacuum furnaces.

[0003]

2. Description of the Related Art Conventionally, as a baking method for a vacuum furnace, generally, a door of a heat insulating material forming a processing chamber is opened, and a carrier gas is ventilated into the furnace while a processing heater attached to the processing chamber is used. Baking inside is done. However, in such a conventional method, even if the inner peripheral surface of the heat insulating material forming the processing chamber can be baked and the outer peripheral surface of the heat insulating material can also be baked to some extent, the vacuum furnace is a water-cooled furnace. If the shell has a shell, there is a drawback that the inner peripheral surface of the water-cooled furnace shell cannot be baked.

[0004]

The problem to be solved by the present invention is that the conventional method cannot bake the inner peripheral surface of the water-cooled furnace shell.

[0005]

DISCLOSURE OF THE INVENTION The present invention is, however, a method of baking a vacuum furnace in which a treatment chamber surrounded by a heat insulating material is formed in a water-cooled furnace shell, which is connected to the water-cooled furnace shell. A method for baking a vacuum furnace, comprising operating a valve to discharge cooling water from the water-cooled furnace shell, and then activating a baking heater mounted between the water-cooled furnace shell and a heat insulating material. A baking apparatus for a vacuum furnace in which a processing chamber surrounded by a heat insulating material is formed in a water-cooled furnace shell,
An automatic valve connected to the water-cooled furnace shell, a baking heater mounted between the water-cooled furnace shell and a heat insulating material, and a controller connected to the power source of the automatic valve and the baking heater. A baking apparatus for a vacuum furnace, wherein the baking heater is energized after the automatic valve is operated to discharge the cooling water of the water-cooled furnace shell according to a signal emitted from the control apparatus. Pertaining to.

The object of the present invention is a vacuum furnace equipped with a water-cooled furnace shell. The furnace shell has a double structure, and cooling water is passed through a hollow portion between the outer furnace shell and the inner furnace shell. A processing chamber surrounded by a heat insulating material is formed in the water-cooled furnace shell, and a processing heater is attached to the processing chamber. Atmosphere gas and carrier gas supply system and vacuum pump exhaust system are connected to the water-cooled furnace shell, and the processing chamber is equipped with rollers and a mounting table for supporting the processed product and the processed product. Needless to say

The water-cooled furnace shell is connected with a valve for supplying and discharging cooling water, or a valve dedicated to supply and a valve dedicated to discharge, and preferably between the water-cooled furnace shell and the heat insulating material. A baking heater is provided on the inner peripheral surface of the water-cooled furnace shell.
For example, a plurality of sheathed heaters are attached.

When baking the inside of the furnace, the door of the heat insulating material forming the processing chamber is generally opened and the processing heater is energized while the carrier gas is being ventilated into the furnace as in the conventional method. In addition to this, the valve is operated to discharge the cooling water in the water-cooled furnace shell, and then the baking heater is energized.

The operation of the valve and the energization of the baking heater can be performed manually, but the valve is an automatic valve, and the power sources of the automatic valve and the baking heater are connected to a control device to control them. It is preferable to automatically control the operation and the bias.

[0010]

The inner peripheral surface and the outer peripheral surface of the heat insulating material forming the processing chamber are baked by the processing heater attached to the processing chamber. The baking of the inner peripheral surface of the water-cooled furnace shell and the auxiliary baking of the outer peripheral surface of the heat insulating material are performed by a baking heater mounted between the water cooled furnace shell and the heat insulating material. Since the baking heater is urged after the cooling water of the water-cooled furnace shell is discharged in advance, the inner peripheral surface of the water-cooled furnace shell can be sufficiently baked by the baking heater.

[0011]

1 is a vertical sectional view schematically showing an embodiment of the present invention. The water-cooled furnace shell 11 has a double structure, and cooling water is passed through a hollow portion 14 between the outer furnace shell 12 and the inner furnace shell 13. A processing chamber 22 surrounded by a heat insulating material 21 is formed in the chamber closed by the water-cooled furnace shell 11, and the processing chamber 22 has processing heaters 23, 24,
25 is attached and a mounting table 26 is also provided.

An automatic valve 31 for supplying and discharging cooling water is connected to the water-cooled furnace shell 11, and the water-cooled furnace shell 1
A plurality of sheathed heaters 41, which are mutually connected as a baking heater, are welded to the inner peripheral surface of 1, that is, the inner peripheral surface of the inner furnace shell 13. The power source 51 for the automatic valve 31 and the sheath heater 41 is connected to the control device 61. After switching the automatic valve 31 to discharge the cooling water in the hollow portion 14 in response to a signal issued from the control device 61, the power source 51 and the sheath heater 41 are connected to energize the sheath heater 41, and the inner furnace shell 13 Baking the inner surface of the.

FIG. 2 is a partially omitted vertical sectional view schematically showing another embodiment of the present invention. Although the other structure which is not described is the same as that of FIG. 1, in this embodiment, an automatic valve 32 dedicated to supplying cooling water and an automatic valve 33 dedicated to discharging cooling water are connected to the water-cooled furnace shell 15. And automatic valve 3
2, 33 and the power source 52 of the sheath heater 42 are the control device 6
It is connected to 2. The automatic valve 32 is closed and the automatic valve 33 is opened to discharge the cooling water in the hollow portion 18 by the signal issued from the control device 62, and then the power source 52 and the sheath heater 42 are connected to energize the sheath heater 42. ,
The inner peripheral surface of the inner furnace shell 17 is baked.

[0014]

As is apparent from the above, the present invention described above has an effect that the inner peripheral surface of the water-cooled furnace shell can be sufficiently baked.

[Brief description of drawings]

FIG. 1 is a vertical sectional view schematically showing an embodiment of the present invention.

FIG. 2 is a partially omitted vertical sectional view schematically showing another embodiment of the present invention.

[Explanation of symbols]

11, 15 ... Water-cooled furnace shell, 21 ... Insulation material, 22 ...
..Processing chambers, 23, 24, 25 ... Processing heaters, 2
6 ... Mounting table, 31, 32, 33 ... Automatic valve,
41, 42 ... Sheath heater, 51, 52 ... Power supply, 61, 62 ... Control device

Claims (2)

[Claims] 1. A method of baking a vacuum furnace in which a treatment chamber surrounded by a heat insulating material is formed in a water-cooled furnace shell, wherein a valve connected to the water-cooled furnace shell is operated to operate the valve. A method for baking a vacuum furnace, comprising activating a baking heater mounted between the water-cooled furnace shell and a heat insulating material after discharging the cooling water. 2. A baking apparatus for a vacuum furnace in which a processing chamber surrounded by a heat insulating material is formed in the water cooling furnace shell, the automatic valve being connected to the water cooling furnace shell, the water cooling furnace shell and the heat insulating material. And a control device connected to the automatic valve and the power source of the baking heater, and the automatic valve is operated by a signal emitted from the control device. A baking apparatus for a vacuum furnace, wherein the baking heater is energized after the cooling water of the water-cooled furnace shell is discharged.