JPH0510678A - Batch type combustion furnace - Google Patents

Abstract

PURPOSE:To obtain a batch type combustion furnace constructed to temporarily and primarily burn in continuation a ceramic molded form. CONSTITUTION:A batch type combustion furnace comprises a combustion chamber 2 for burning a material to be burned by radiation transfer heat, an intermediate chamber 3 provided to be opened at the upper part of the chamber 2, a preheating chamber 4 provided to be opened at the side of the chamber 3, preheating gas supply means 6, 7 provided in the chamber 4 to supply preheating gas G1 into the chamber 2 through the chamber 3, and a drive wall 8 for opening/closing the opening of the chamber 4 by vertically moving in the chamber 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a batch-type firing furnace used for firing an article to be fired such as a ceramic molded body.

[0002]

2. Description of the Related Art Conventionally, in order to fire a ceramic molded body which is an object to be fired, first, calcination (debinding) is performed in a low temperature range of 500 to 600 ° C. and then 1300 ° C.
The main calcination (sintering) is performed in a high temperature range. When the ceramic molded body is fired, convective heat transfer is dominant in a low temperature range of 500 to 600 ° C., while radiant heat transfer is dominant in a higher temperature range than this. In order to efficiently burn the body, it is necessary to adopt the most effective heat transfer method in each temperature range.

Therefore, in a conventional batch-type firing furnace (not shown) for pre-baking, an in-furnace convection fan made of a heat-resistant alloy is installed in the firing chamber, and firing is performed by rotating the in-furnace convection fan. The ceramic compact is pre-baked while forcing the convection of the atmospheric gas in the room.

[0004]

By the way, since such a convection fan in a furnace usually withstands only a temperature range of about 600 ° C., a temporary housing containing a ceramic molded body which has been pre-baked is required. It is not possible to raise the atmospheric temperature in the firing chamber of the batch type firing furnace for firing to about 1300 ° C. and subsequently perform the main firing of the ceramic molded body. Therefore, these pre-fired ceramics compacts are taken out of the firing chamber of the batch firing furnace for pre-firing and transferred to the firing chamber of the batch firing furnace for main firing that is installed separately In the present situation, the ceramics compact is subjected to main firing by raising the ambient temperature to about 1300 ° C. by radiative heat transfer. It should be noted that it is conceivable that the ceramic molded bodies are housed in the firing chamber of the main firing batch type firing furnace and the ceramic molded bodies are fired by radiative heat transfer from the beginning. Therefore, it takes a very long time to fire the ceramic molded body, which leads to a significant decrease in productivity. Therefore, it is not generally adopted.

Therefore, in the conventional example, it is necessary not only to separately install a batch type baking furnace for pre-baking mainly for convective heat transfer and a batch type baking furnace for baking mainly for radiative heat transfer. However, it is necessary to take out, carry, and re-store the pre-fired ceramics molded body, which causes an increase in installation cost and a great deal of troublesome work.

The present invention was devised in view of such inconvenience, and an object of the present invention is to provide a batch-type firing furnace capable of continuously performing preliminary firing and main firing of a ceramic molded body.

[0007]

In order to achieve such an object, a batch type firing furnace according to the present invention has a firing chamber for firing an object to be fired by radiative heat transfer and an opening at an upper portion of the firing chamber. An intermediate chamber provided with a preheating chamber provided on the side of the intermediate chamber, and a preheating gas installed in the preheating chamber and supplying a preheating gas into the firing chamber through the intermediate chamber. It is characterized by comprising a supply means and a drive wall which moves up and down in the intermediate chamber to open and close the opening of the preheating chamber.

[0008]

According to the above construction, the firing chamber and the preheating chamber provided with the preheating gas supply means are separately provided, and the intermediate chamber is provided between them, and the intermediate chamber is moved up and down to move the preheating chamber. Since a drive wall for opening and closing the opening of the preheating chamber is provided, the preheating gas supplied from the preheating atmosphere supply means flows into the firing chamber through the intermediate chamber when the driving wall is raised and the opening of the preheating chamber is opened. While the ceramic molded body is heated by convective heat transfer, the preheating gas is no longer supplied when the drive wall descends and the opening of the preheating chamber is closed, so that the ceramic molded body by radiant heat transfer Only heating will be done.

[0009]

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

1 to 3 each show a schematic structure of a batch type firing furnace according to this embodiment. FIG. 1 is a longitudinal sectional view of a ceramics compact heated by convection heat transfer, and FIG. FIG. 3 is a vertical cross-sectional view when heating the ceramic molded body by heat, and FIG. 3 is a horizontal cross-sectional view taken along the line AA of FIG.

The batch type firing furnace according to the present embodiment is used for pre-firing and main firing of a ceramic molded body which is an object to be fired, and the batch type firing furnace is housed in the sagger 1. Of the ceramic molded body (not shown) placed by means of radiant heat transfer, an intermediate chamber 3 opened at the upper part of the firing chamber 2, and an intermediate chamber 3 It is provided with a preheating chamber 4 which is opened at a side portion. And inside the firing chamber 2,
Si for radiative heat transfer to a ceramic compact
The C heater 5 is provided at each predetermined position.

Further, in the preheating chamber 4, a preheating gas supply means for supplying the preheating gas G ₁ into the firing chamber 2 through the intermediate chamber 3 is installed, and the preheating gas supply means is provided from outside the furnace. The furnace is composed of a convection fan 6 in the furnace for stirring the supplied atmospheric gas G ₂ and an electric heater 7 for heating the atmospheric gas G ₂ to a predetermined temperature. Further, inside the intermediate chamber 3 provided by connecting the firing chamber 2 and the preheating chamber 4 in communication with each other, a drive wall 8 that opens and closes to open and close the opening of the preheating chamber 4 is provided in a suspended and supported state. The drive wall 8 is connected to an electric motor 10 installed outside the furnace via a chain 9 which is a transmission body. Here,
In the figure, reference numeral 11 is an atmosphere gas introduction pipe for introducing the atmosphere gas G ₂ into the preheating chamber 4, 12 is a solenoid valve for controlling introduction and stop of the atmosphere gas G ₂ , and 13 is a transmission belt 14. It is an electric motor that rotationally drives the convection fan 6 in the furnace.

Further, at the lower part of the baking chamber 2 for accommodating the sagger 1, there is provided an opening portion which is closed by a hearth 15. The hearth 15 is an elevating and lowering part constituted by using a screw jack or the like. It can be moved up and down by a device (neither shown). Then, at each predetermined position of the hearth 15, together with the firing gas introduction pipe 16 for introducing the firing gas G ₃ required for radiative heat transfer into the firing chamber 2, the firing supplied into the firing chamber 2 Gas G
Gas discharge pipe 1 for discharging ₃ and preheated gas G _{1 out} of the furnace
7 is attached in a penetrating state along the vertical direction.

Here, reference numeral 18 in the drawing is a baking chamber 2.
And a hearth 15 are sealed by a lower sealing mechanism, 19 is an upper sealing mechanism that keeps the intermediate chamber 3 and the drive wall 8 sealed, and the lower sealing mechanism 18 is the outer steel plate 2a of the firing chamber 2. And an elastic member 15a such as silicon attached to the hearth 15. In addition, the upper sealing mechanism 19 includes the sealing steel plate 3 attached to the intermediate chamber 3.
a and an elastic seal plate 8a arranged on the drive wall 8 are fitted to each other. In the space S formed by the elastic seal plate 8a, the supply side and discharge side solenoid valves 20, 2 are provided.
The sealing gas Gs is introduced through 1.

Next, the operation and action of the batch type firing furnace according to this embodiment will be described. The ceramic molded body housed in the bowl 1 is first calcined (removed from the binder) in a low temperature range of 500 to 600 ° C., but the drive wall 8 is raised during this calcining. The opening of the preheating chamber 4 provided on the side of the intermediate chamber 3 is open. The atmospheric gas G ₂ supplied from outside the furnace is heated to a predetermined temperature by the electric heater 7 while being stirred by the convection fan 6 inside the furnace to become the preheated gas G _1, and the opening of the preheating chamber 4 and the intermediate chamber 3 It will flow into the firing chamber 2 through and. Therefore, the ceramic molded body in the sagger 1 placed in the firing chamber 2 is heated by the preheated gas G ₁ that is forcibly supplied, that is, the heating is performed by the forced convection heat transfer. That is, the ceramic molded body is pre-baked. In addition,
At the time of this calcination, the supply side solenoid valve 20 constituting the upper sealing mechanism 19 is opened, and the space S formed by the elastic sealing plate 8a is filled with the sealing gas Gs.

Further, with respect to the ceramic compact which has been preliminarily fired in this way, it is continuously heated to 1300 ° C.
Main firing (sintering) is performed in a high temperature range of about a certain degree. The drive wall 8 at the time of the main firing is lowered inside the intermediate chamber 3, and the preheating chamber 4 provided on the side portion of the intermediate chamber 3
The opening is closed by the drive wall 8. Therefore, the intermediate chamber results preheating gas G ₁ is not supplied from the 3, convective heat transfer due to the preheating gas G ₁ for the ceramic molded body is not performed. That is, the main firing by radiative heat transfer of the ceramic molded body housed in the bowl 1 is performed by the SiC heater 5 attached to the firing chamber 2.
Will be done through. Then, the firing gas G ₃ is introduced from the firing gas introduction pipe 16 into the firing chamber 2 during the main firing, but since the opening of the preheating chamber 4 is closed by the drive wall 8, Firing gas G
It is impossible for ₃ to flow into the preheating chamber 4.
At this time, the discharge side electromagnetic valve 21 constituting the upper seal mechanism 19 is opened to reduce the pressure in the space S.

After that, the ceramic compact after the main firing is cooled, and at this time, the drive wall 8 is raised again and the opening of the preheating chamber 4 is opened. Then, the atmospheric gas G ₂ supplied from outside the furnace flows into the firing chamber 2 while being stirred by the convection fan 6 inside the furnace, and due to convective heat transfer of the ceramic molded body housed in the sagger 1 Forced cooling will be performed.

[0018]

As described above, in the batch type firing furnace according to the present invention, the preheating gas supply for supplying the preheating gas for performing the convective heat transfer and the firing chamber for heating the object to be fired by the radiative heat transfer. The preheating chamber in which the means is installed is provided separately, and an intermediate chamber is provided between them, and a drive wall for vertically moving the intermediate chamber to open and close the opening of the preheating chamber is provided. When the wall rises and the opening of the preheating chamber is opened, the preheating gas supplied from the preheating atmosphere supply means flows into the firing chamber through the intermediate chamber, and heating of the ceramic molded body by convective heat transfer is performed. Become. Further, in the state where the drive wall descends and the opening of the preheating chamber is closed, the preheating gas is not supplied, and only the ceramic molded body is heated by the radiative heat transfer. As a result, according to the present invention, it is possible to obtain an effect that the calcination and the main calcination of the ceramic molded body which is the object to be calcinated can be easily and easily continuously performed by moving the drive wall up and down.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a batch-type firing furnace when heating a ceramic molded body by convective heat transfer.

FIG. 2 is a vertical cross-sectional view showing a schematic configuration of a batch-type firing furnace when heating a ceramic molded body by radiative heat transfer.

3 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

2 Firing chamber 3 Intermediate chamber 4 Preheating chamber 6 In-furnace convection fan 7 Electric heater 8 Drive wall G ₁ Preheating gas

Claims (1)

Claims: 1. A firing chamber (2) for firing an object to be fired by radiative heat transfer, and an intermediate chamber (3) provided at an upper portion of the firing chamber (2). A preheating chamber (4) opened to the side of the intermediate chamber (3) and installed in the preheating chamber (4) and through the intermediate chamber (3) in the firing chamber (2). A preheating gas supply means (6, 7) for supplying a preheating gas (G ₁ ) to the inner wall of the intermediate chamber (3), and a drive wall (8) for vertically moving in the intermediate chamber (3) to open and close the opening of the preheating chamber (4). A batch-type firing furnace characterized by comprising: