JPH0526580A - Continuous baking furnace - Google Patents

Abstract

PURPOSE:To obtain a continuous baking furnace capable of discharging binder gas to the outside of the furnace without disturbing temperature distribution in the furnace. CONSTITUTION:The title furnace is provided with a low temperature zone 1, in which binder included in forms 7 not baked yet is evaporated, a middle temperature zone 2, in which the forms 7 not baked yet are preheated, and a high temperature zone 3, in which the forms 7 not baked yet are baked. The title furnace is added with a discharging gas removing mechanism 5, introducing heating air 57 from the upper part of the furnace of the low temperature zone 1 and discharging it through the floor 12 of the furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous firing furnace used when firing an unfired ceramic.

[0002]

2. Description of the Related Art In order to prevent defective firing due to absorption of a binder gas generated in a low temperature zone, a ventilation fan is used in a conventional continuous firing furnace to forcibly discharge the gas from the low temperature zone.

[0003]

However, the conventional continuous firing furnace has the following drawbacks. It is necessary to adjust the capacity of the ventilation fan according to the amount of binder gas generated, and along with this, an air flow according to the ventilation capacity is generated in the furnace, and the temperature distribution in each temperature zone is disturbed. An object of the present invention is to provide a continuous firing furnace capable of discharging the binder gas outside the furnace without disturbing the temperature distribution inside the furnace.

[0004]

[Means for Solving the Problems] In order to solve the above problems,
The present invention is directed to a low temperature zone located near an inlet for evaporating a binder contained in a body to be fired, and a medium temperature zone located behind the low temperature zone for preheating a body to be fired that has passed through the low temperature zone. And a continuous firing furnace that is located behind the intermediate temperature zone and has a high temperature zone for firing the article to be fired that has passed through the intermediate temperature zone, in which heated air is introduced from the furnace upper part of the low temperature zone A structure with an exhaust gas removal mechanism for exhausting from the section was adopted.

[0005]

Function: The binder contained in the article to be fired evaporates in the low temperature zone, and the binder gas accumulates in the furnace in the low temperature zone. The exhaust gas removal mechanism introduces heated air from the upper part of the furnace in the low temperature zone,
Exhaust from the hearth (Damplow method). Therefore, the binder gas is forcibly discharged to the outside of the furnace without generating a lateral air flow inside the furnace.

[0006]

EFFECTS OF THE INVENTION Introducing heated air from the upper part of the furnace in the low temperature zone,
Since the gas is exhausted from the furnace floor, the air current does not flow in the lateral direction of the furnace, and the binder gas can be discharged to the outside of the furnace without disturbing the temperature distribution in the furnace.

[0007]

EXAMPLE An example of the present invention will be described below with reference to FIGS. As shown in FIGS. 1 and 4, continuous firing furnace A
Includes a low temperature zone 1, a medium temperature zone 2, a high temperature zone 3, and a cooling zone 4,
Exhaust gas removing mechanism 5 for forcibly discharging the binder gas 10,
And a hot air discharge mechanism 6. Further, in this continuous firing furnace A (total length: several tens of meters), the furnace wall is made of a refractory material, and the base plate (or dolly) 110 made of a heat-resistant material is movably arranged on the hearth rail 100 and is not yet mounted. The fired compact 7 is placed.
The green body 7 carried in through the inlet 130 on the left side of the drawing moves in the furnace by the pusher method and is carried out as a product through the outlet 140 on the right side of the drawing.

The low temperature zone 1 is located in the vicinity of the inlet 130, and the temperature distribution is set by the electric heater 11 such that the front portion has room temperature and the rear portion has 500 ° C. Moreover, when the green body 7 passes through the low temperature zone 1, the organic binder described later evaporates. The middle temperature zone 2 is located at the rear part of the low temperature zone 1, and the front part is 600 ° C. and the rear part is 1 degree by the electric heater 21.
The temperature distribution is set to be 300 ° C. The unsintered compact 7 that has passed through the low temperature zone 1 is preheated in the middle temperature zone 2 so as to be easily sintered. The high temperature zone 3 is located at the rear part of the middle temperature zone 2, and the temperature distribution is set by the electric heater 31 so that the front part becomes 1300 ° C. and the rear part becomes 1600 ° C. The green compact 7 that has passed through the low temperature zone 1 is the high temperature zone 3
Is baked in. The cooling zone 4 is air-cooled, and the high temperature zone 3
The product passed through is cooled to room temperature.

The exhaust gas removing mechanism 5 is, as shown in FIG.
Three exhaust pipes 51 (stainless steel having an inner diameter of 46 mm and an outer diameter of 50 mm) communicating with the openings 120 formed on the side of the hearth rail 100 of the hearth portion 12 of the low temperature zone 1, and the pipe 5
1, an aspirator 53 with an air amount adjusting valve 52 (stainless steel having an inner diameter of 4 mm and an outer diameter of 5 mm), and a compressor 55 for supplying air 54 to the aspirator 53.
And a heated air introduction part for introducing heated air 57 from the furnace upper part 13 by arranging the heat receiving pipe 56 along the outer wall of the furnace from the high temperature zone 3 to the medium temperature zone 2. The air amount adjusting valve 52 is a control device 8 to which the outputs of the water vapor sensor 81 and the carbon dioxide sensor 82 are input.
The opening degree is controlled so that the amount of water vapor and the concentration of carbon dioxide in the low temperature zone 1 do not exceed 80% and 2%, respectively.

As shown in FIG. 3, the hot air exhaust mechanism 6 includes four exhaust heat pipes 61 (having an inner diameter of 46 mm and an outer diameter of 50 mm) arranged at the upper part of the furnace in the high temperature zone 3 (partially medium temperature zone 2). (Stainless steel), air amount adjusting valve 6 attached to the pipe 61
2 and an aspirator 63 (stainless steel having an inner diameter of 4 mm and an outer diameter of 5 mm) and a compressor (not shown) that supplies air to the aspirator 63, and the alkaline glass gas containing air is 0.5 m ³ / min to 1. Discharge to the outside of the furnace at a rate of 5 m ³ / min. The air amount adjusting valve 62 is electrically connected to the control device 8 to which the outputs of the temperature sensors 83 and 84 are input, and the opening degree is operated so that the front and rear temperatures do not change significantly.

The green compact 7 is made of 90% by weight of alumina,
A ceramic material composed of 3.3% by weight of silicon, 3% by weight of calcium oxide and 3% by weight of magnesium oxide, and 3 to 5% by weight of cellulose and paraffin 3 as an organic binder.
-5% by weight and 0.5% by weight of water are contained to form a predetermined shape.

Next, the function and effect of the continuous firing furnace A will be described. (A) Since the binder gas 10 in the low temperature zone 1 is efficiently discharged to the outside of the furnace, the product is free from cracks and distortion. (A) Exhaust from the hearth 12 of the low temperature zone 1 and introduce heated air 57 from the furnace upper part 13 of the low temperature zone 1 to generate the binder gas 1
Since 0 is discharged to the outside of the furnace, the temperature distribution of the low temperature zone 1, the middle temperature zone 2 and the high temperature zone 3 is not disturbed. (C) By changing the opening degree of the air amount adjusting valve 52, the discharge amount of the binder gas 10 can be varied over a wide range. (D) Due to the hot air discharge mechanism 6, the alkaline glass gas generated during firing is discharged in a short time, the product is not contaminated with the alkaline glass gas, and the electric heaters 11, 21, 31 and the furnace inner wall are not damaged. Since the amount of alkaline glass gas containing air discharged by the hot air discharge mechanism 6 is small (the amount of alkaline glass gas generated is small), the air flow flowing toward the high temperature zone 3 is extremely small, and Does not significantly disturb the temperature distribution of. (E) In the conventional continuous furnace, since the ventilation fan is arranged in the exhaust duct, it takes time and effort to clean the carbon and unburned resin adhering to the inside of the duct. In the continuous firing furnace A of this embodiment, no ventilation fan is provided in the exhaust duct 50, so that cleaning the duct does not take time. (F) Since the air is heated by utilizing the exhaust heat of the high temperature zone 3 and the medium temperature zone 2, it is not necessary to separately prepare energy for heating.

[Brief description of drawings]

FIG. 1 is a structural diagram of a continuous firing furnace that is an embodiment of the present invention.

FIG. 2 is a structural explanatory view of an exhaust gas removing mechanism (a part) in the continuous firing furnace.

FIG. 3 Hot air discharge mechanism in the continuous firing furnace (part)
It is a structure explanatory view of.

FIG. 4 is a sectional view of a low temperature zone of the continuous firing furnace.

[Explanation of symbols]

 A Continuous firing furnace 1 Low temperature zone 2 Medium temperature zone 3 High temperature zone 5 Exhaust gas removal mechanism 7 Unsintered compact (sintered compact) 12 Hearth 13 Upper furnace 57 Heated air 130 Inlet

Claims (1)

Claim: What is claimed is: 1. A low temperature zone located near the inlet for evaporating the binder contained in the article to be fired, and a low temperature zone located behind the low temperature zone and passed through the low temperature zone. In a continuous firing furnace provided with a medium temperature zone for preheating a molded body, and a high temperature zone located behind the medium temperature zone for burning the molded body that has passed through the medium temperature zone, from the furnace upper part of the low temperature zone A continuous firing furnace, characterized by adding an exhaust gas removal mechanism for introducing heated air and exhausting it from the hearth.