JPH08136141A - Heat treatment furnace - Google Patents

Abstract

PURPOSE: To provide a heat treatment furnace in which degreasing process can be carried out over an entire environment of a ceramic formed product within a short period of time without using any large amount of atmospheric gas and which can be used during a degreasing treatment and a burning time. CONSTITUTION: A first heat treatment furnace is comprised of a tool material 3 which is arranged within a heating chamber 2 after a ceramic formed produced S to be degreased is installed within the furnace and this tool material 3 is made by porous raw material having aeration characteristic. In addition, a second heat treatment furnace is constructed such that gas supplying pipes 4 for supplying atmospheric gas G are installed at a ceiling side in the heating chamber 2 and in turn a gas discharging pipe 6 is opened at a floor surface of the heating chamber 2 and then an opening of the gas discharging pipe 6 is closed by the tool material 3 made by porous raw material having aeration characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment furnace used for degreasing ceramic molded products.

[0002]

2. Description of the Related Art Conventionally, when a ceramic molded product, which is a chip component such as a monolithic ceramic capacitor or a deformed component such as a transformer core, is manufactured, it is subjected to a firing treatment, and prior to the firing treatment. In general, a degreasing treatment is generally performed in advance to remove the binder required during molding from the ceramic molded product. That is, when firing treatment is performed without degreasing treatment, the ceramic molded product is cracked, peeled, or deformed due to the remaining binder, and the product function is lost. Therefore, in order to avoid such an inconvenience, it is necessary to sufficiently degrease the ceramic molded product.

By the way, when degreasing ceramic molded products, it is common to use a batch type heat treatment furnace suitable for high-mix low-volume production or a continuous heat treatment furnace such as a pusher type suitable for mass production. Although not shown, in these heat treatment furnaces, the box that is the tool material on which the ceramic molded product to be degreased is placed is placed in the heating chamber, and the atmosphere gas is strictly controlled. Meanwhile, the degreasing treatment is to be performed at a temperature of 400 to 500 ° C. for 20 hours or more.
The degreasing treatment for such a long time is
This is because the binder is sufficiently released from the ceramic molded product, and a large amount of atmospheric gas is supplied to the released binder.

[0004]

However, in the above-described conventional heat treatment furnace, the following disadvantages have occurred. That is, first, it is difficult to circulate the atmospheric gas supplied into the heating chamber in a state where it is in sufficient contact with the ceramic molded product placed on the box, and in particular, the binder from the contact part of the ceramic molded product with the box is difficult. It was difficult to release the satisfactorily.
Then, many defects will occur in the contact portion of the ceramic molded product where the binder is not sufficiently discharged, which causes a quality problem.

Further, when the processing amount of the ceramic molded article which is degreased using this heat treatment furnace is increased, it is necessary to further increase the supply amount of the atmospheric gas, and the furnace containing the released binder is required. As a result of the increase in the total amount of exhaust gas discharged to the outside, the exhaust gas treatment also requires a great deal of labor and cost. Furthermore, the binder discharged from the ceramic molded product may contaminate the heating chamber, and the binder remaining in the heating chamber may adversely affect the atmosphere gas during the firing process. The furnace cannot be used during the firing process of the ceramic molding.

The present invention was devised in view of these inconveniences, and can easily perform degreasing treatment over the entire circumference of a ceramic molded article in a short time without using a large amount of atmospheric gas. The present invention aims to provide a heat treatment furnace that can be used for both degreasing treatment and firing treatment.

[0007]

In order to achieve such an object, the first heat treatment furnace according to the present invention is placed in a heating chamber after a ceramic molded article to be degreased is placed. A tool material is provided, and the tool material is characterized by being manufactured using a porous material having air permeability. In the second heat treatment furnace, a gas supply pipe for supplying an atmospheric gas is installed on the ceiling side in the heating chamber, while a gas discharge pipe is opened on the floor surface in the heating chamber. It is characterized in that the opening of the gas discharge pipe is closed with a tool material made of a quality material.

[0008]

According to the first structure, since the tool material made of the air permeable porous material is used, the atmospheric gas can flow inside the tool material. Atmosphere gas also spreads and makes sufficient contact with the contact portion of the molded product with the tool material. Therefore, as a result of sufficient contact while the atmospheric gas flows around the entire circumference of the ceramic molded product, it is not necessary to increase the supply amount of the atmospheric gas so much even if the processing amount is increased. Can be prevented. Further, when the second configuration is adopted, the binder discharged from the ceramic molded product passes through the tool material and then flows into the gas discharge pipe, so that the discharged binder diffuses into the heating chamber. Does not occur, and contamination of the heating chamber by the binder does not occur.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing a simplified cross-sectional structure of a heat treatment furnace according to this embodiment. The heat treatment furnace shown in FIG. 1 may be either a batch type or a continuous type.

The heat treatment furnace according to this embodiment comprises a furnace body 1 made of a heat insulating material having a predetermined thickness, and a heating chamber 2 surrounded by the furnace body 1, and should be degreased. Ceramic molded products such as chip parts and odd-shaped parts S
It is equipped with a box 3 which is a tool material placed in the heating chamber 2 after being placed. The box 3 in this case is made of a porous material having air permeability, for example, a ceramic having a large apparent porosity of about 50 to 90%, and has a flat plate shape with a predetermined thickness. ing. It is needless to say that the box 3 may have a box shape with only the upper side opened.

On the other hand, on the ceiling side in the heating chamber 2 in which the box 3 is housed, between the gas supply pipe 4 for supplying the atmospheric gas G suitable for degreasing the ceramic molded product S and the side wall of the furnace body 1. The electric heaters 5 installed in the heating chamber 2 are arranged so as to intersect with each other, and a gas discharge pipe 6 is opened on the floor surface in the heating chamber 2. The opening of the gas discharge pipe 6 is formed in a tapered shape in a side view with the heating chamber 2 side expanded, and the middle portion of the gas discharge pipe 6 drawn out of the furnace is for cleaning the exhaust gas. An exhaust gas purification device 7 having a general structure is attached. Furthermore, the box 3 made of a porous material having air permeability is placed on the opening of the gas exhaust pipe 6 on the floor in the heating chamber 2. The opening is closed by the box 3.

Next, the operation and action of the heat treatment furnace according to this embodiment will be described.

First, in the present embodiment, the gas supply pipe 4
The fresh atmospheric gas G supplied from the electric heater 5 and heated by the electric heater 5 flows from the upper side to the lower side in the heating chamber 2, and the flowing atmospheric gas G has a breathability. After passing through the inside of 3, the gas flows into the opening of the gas discharge pipe 6. Therefore, with respect to the ceramic molded product S placed on the box 3, the atmospheric gas G is spread over the entire circumference including the contact portion where the ceramic molded product S is in contact with the box 3. ,
Each of the ceramic molded products S is in sufficient contact with the atmospheric gas G.

Therefore, the binder is released from the ceramic molded product S that has been subjected to the degreasing treatment by coming into contact with the ambient gas G, and the released binder is gas together with the ambient gas G passing through the box 3. Discharge pipe 6
It flows into. Therefore, the binder released at this time cannot diffuse into the heating chamber 2 and remain there, and the binder in the exhaust gas flowing through the gas exhaust pipe 6 is removed by the exhaust gas purifying device 7. I will end up.
Then, the inventors of the present invention conducted an experiment and found that the time required for degreasing the ceramic molded product S when using the heat treatment furnace including the box 3 having the above-mentioned configuration was about half that of the conventional example, Further, it has been confirmed that the degreased state is uniform in the entire periphery of the ceramic molded product S.

[0016]

As described above, according to the heat treatment furnace of the present invention, the atmospheric gas circulates inside the tool material,
As a result of the atmospheric gas reaching the parts of the ceramic molded product that come into contact with the tool material, sufficient contact is made while the atmospheric gas flows around the entire circumference of the ceramic molded product. The effect that the time required for the treatment can be greatly shortened and the degreased state can be made uniform in the entire circumference of the ceramic molded product can be obtained. Further, it is possible to prevent the occurrence of defects in the ceramic molded product, and it is possible to realize stable product characteristics.

Further, there is also an advantage that it is not necessary to supply a large amount of atmospheric gas in the degreasing process of the ceramic molded product, and the labor and cost required for the exhaust gas process can be reduced. The binder released from the ceramic molded article does not diffuse into the heating chamber, and the heating chamber is not contaminated by the binder. Therefore, the heat treatment furnace according to the present invention is used in both the degreasing process and the firing process. The effect of being able to do is obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a simplified cross-sectional structure of a heat treatment furnace according to the present embodiment.

[Explanation of symbols]

 2 Heating chamber 3 Box (tool material) 4 Gas supply pipe 6 Gas discharge pipe S Ceramic molded product G Atmosphere gas

Claims (2)

[Claims] 1. A ceramic molded product (S) to be degreased.
Is equipped with a tool material (3) placed in the heating chamber (2), and the tool material (3) is made of a porous material having air permeability. A heat treatment furnace characterized by being present. 2. A gas supply pipe (4) for supplying an atmospheric gas (G) is installed on the ceiling side in the heating chamber (2),
A gas discharge pipe (6) is opened on the floor in the heating chamber (2), and the opening of the gas discharge pipe (6) is closed by a tool material (3). Item 2. A heat treatment furnace according to item 1.