JPH0711392B2 - Ceramic firing furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a ceramic firing furnace used for firing a manganese-zinc based electronic ceramic material or the like.

[Prior Art] Generally, when firing a manganese / zinc-based electronic ceramic material or the like, a large amount of air (oxygen) necessary for the oxidation reaction is required in the temperature rising process from 600 ° C to 800 ° C. Through 800
After ℃, oxygen partial pressure is 0 due to compound formation.
It must be controlled to be 1% to 0.01%.

Conventionally, a so-called tunnel-type continuous firing furnace having a furnace body having a tunnel shape has been used for firing the manganese / zinc-based electroceramic material that requires such heat treatment. This continuous firing furnace is divided into a region into which a large amount of air (oxygen) is introduced during the temperature rising process of the ceramic firing object and a region into which an atmospheric gas (nitrogen) is introduced during the firing process of the ceramic firing target. An electric heater is used as a heat source. This electric heater is installed in the furnace main body, and is continuously pushed from one end opening of the furnace main body toward the other end opening to continuously move in the furnace main body to heat a ceramic object to be fired.

[Problems to be Solved by the Invention] In the above-mentioned conventional ceramic firing furnace, since air (oxygen) is supplied during the temperature rising process from 600 ° C to 800 ° C, a large amount of heat is required to heat the air. Must be supplied by an electric heater. Further, since the above ceramic firing furnace is of a tunnel type, the internal space of the furnace body is open to the outside through the openings at both ends of the furnace body, and the temperature is 600 ° C.
Or to control the oxygen partial pressure low after 800 ℃,
Requires a large amount of nitrogen. Therefore, the conventional ceramic firing furnace has a large amount of electricity and gas used,
There was a problem that the running cost was very high.

Further, since the above-mentioned conventional ceramic firing furnace is a continuous type, it is not suitable for the production of a small amount of a wide variety of ceramic products, and moreover, since the furnace body is a tunnel type having openings at both ends, There was also the problem that it was difficult to control the atmosphere.

An object of the present invention is to provide an energy-saving ceramic firing furnace which is suitable for the production of a large amount of ceramic products in small quantities and has a low running cost.

[Means for Solving the Problem] For this reason, the present invention has a vertical furnace main body in which a ceramic object to be fired is put in and taken out from a hearth or a side wall, and is housed in the furnace main body. In the heating process of the ceramic fired object, a large amount of oxygen is introduced into the furnace body to heat the ceramic fired object, while in the firing process of the ceramic fired object, atmospheric gas is fed into the furnace body. In a firing furnace for firing the ceramic object to be fired while controlling the oxygen partial pressure, and a gas heat source for supplying a combustion gas into the furnace body to heat the ceramic object to be fired during the heating process. An electric heater heat source for heating the ceramic object to be fired in the above firing process is provided.

[Operation] The above-mentioned temperature rise and firing of the object to be fired of the ceramic are performed in the closed vertical furnace body. As the energy required for heating a large amount of air (oxygen) supplied to oxidize the material to be fired of ceramics in the temperature rising process, combustion gas whose energy cost is lower than that of electricity is used. On the other hand, in the above firing process, which consumes significantly less energy,
The object to be fired of ceramic is fired by the heat source of the electric heater whose precise temperature control is easy.

EFFECTS OF THE INVENTION According to the present invention, a ceramic object to be fired is fired in a closed furnace body, and is heated by a gas heat source having a low energy cost in a heating process requiring a large amount of energy. In the firing process, which consumes less energy, it is heated by an electric heater heat source that allows easy precise temperature control. Therefore, in the heating process, the amount of oxygen required to oxidize the material to be fired in the ceramic and the amount of heat required for heating are inexpensive. Can be quickly and uniformly supplied into the furnace body, and during the firing process,
It is possible to switch to a precise oxygen partial pressure atmosphere quickly and accurately.

Further, since the present invention is of a batch type, it can be applied to the production of various kinds of ceramic products in small quantities.

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

A longitudinal section of an embodiment of a ceramic firing furnace according to the present invention is shown in the drawing.

The ceramic firing furnace has a vertical furnace body 2 supported on a hollow support 1, and a furnace floor 3 of the furnace body 2 moves up and down with respect to a lower opening 2a of the furnace body 2. It is a floor lift type. The hearth 3 is moved up and down between an I position (a clogged position) shown by a solid line and a II position (a crawled position) shown by a dotted line in the figure by a screw jack or a hydraulic table lifter (not shown). .

In the furnace body 2, the furnace body 2 is crossed across the inner space 4.
A plurality of rows of silicon carbide-based rod-shaped electric heaters 5 are arranged at intervals above and below the furnace body 2 so as to bridge the inner walls of the furnace. In the state where the hearth 3 is raised to the position I, the box 10 in which ceramic objects to be fired (not shown) are housed on the hearth 3 and stacked in multiple stages is an electric heater. 5 are arranged between adjacent rows.
Further, a silicon rubber 13a is fixed to the bottom wall of the furnace main body 2, and when the hearth 3 is raised to the position I, the L-shaped metal fitting 13b on the hearth 3 side comes into close contact with the silicon rubber 13a, The airtightness of is maintained.

The vertical distance d, the horizontal distance L, and the length of the heating portion of the electric heater 5 vary depending on the filling amount of the ceramic material to be fired in the furnace body 2. In this embodiment, 10 electric heaters 5 having a diameter of 30 mm and a length of 1000 mm to 1800 mm are provided in the furnace body 2 in the vertical direction and 4 in the horizontal direction.
A total of 40 columns are used and these electric heaters 5 are independently controlled by 8 circuits.

The furnace main body 2 is provided with two burner ports 6 at two locations on each lower part of the pair of side walls 7 facing each other. These burner ports 6 are connected to the burner 11. A partition wall 8 is provided in the furnace body 12 so as to face the burner ports 6. Combustion gas supplied into the furnace body 2 from each of the burner ports 6 hits the partition walls 8 to form side walls 7 of the furnace body 2.
After going up to the furnace ceiling 12 in the furnace main body 2 along the passage, it passes between each row of the boxes 10 stacked in multiple stages,
The gas is discharged to the outside of the furnace main body 2 from the exhaust gas discharge port 9 provided in the. In this process, the air supplied into the furnace body 2 is heated and supplied to the ceramic object to be fired in the box 10.

The burner ports 6 may be provided in three places on each of the pair of side walls 7, that is, a total of six places, and the partition walls 8 may be arranged in a staggered manner.

In the firing process of the ceramic firing object, the burner port 6 is used.
The supply of combustion gas is stopped, and nitrogen gas is supplied into the furnace body 2 through a gas supply port (not shown).

In the above firing furnace, the energy required for heating a large amount of air (oxygen) supplied for the oxidation of the material to be fired in the ceramic in the temperature rising process from 600 ° C. to 800 ° C. Is used. On the other hand, in the above-mentioned firing process in which the energy consumption is remarkably low, the firing target of the ceramic is fired by the electric heater 5 whose precise temperature control is easy.

As a result, in the temperature rising process, the amount of oxygen required for the oxidation reaction of the material to be fired of ceramics and the amount of heat required for heating are rapidly and uniformly supplied to the furnace body at low cost. In the firing process, the oxygen atmosphere can be switched to a precise oxygen atmosphere quickly and accurately.

Further, since the temperature raising process and the firing process of the ceramic firing object are performed in a batch furnace having a closed vertical furnace body, it is possible to easily produce a large variety of ceramic products in small quantities.

The present invention can be applied not only to a hearth elevating and lowering type ceramic firing furnace, but also to a furnace having a door for taking in and out a box on the wall surface of the furnace body.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a ceramic firing furnace according to the present invention. 2 ... furnace body, 2a opening, 3 ... hearth, 5 ... electric heater, 6 ... burner port, 7 ... side wall, 8 ... bulkhead, 9 ...
Exhaust gas exhaust port, 10 …… box, 11 …… burner, 12 …… furnace ceiling.

Claims (1)

[Claims] 1. A vertical furnace body for loading and unloading a ceramic object to be fired from a hearth or a side wall,
In the process of raising the temperature of the material to be fired of the ceramic housed in the furnace body, while heating the material to be fired of the ceramic while introducing a large amount of oxygen into the body of the furnace, the process of firing the material to be fired of the ceramic In a firing furnace in which an atmosphere gas is introduced into the furnace body to control the oxygen partial pressure to fire the ceramic object to be fired, the combustion gas is supplied into the furnace body in the temperature rising process to fire the ceramic object to be fired. A ceramic firing furnace, comprising: a gas heat source for heating an object; and an electric heater heat source for heating a ceramic object to be fired in the firing process.