JPH04270884A - Roller hearth continuous furnace - Google Patents

Abstract

PURPOSE:To provide a roller hearth continuous furnace capable of baking and cooling in the ways stabilized atmosphere without being affected by the fluctuation of the flame of a gas burner and the like. CONSTITUTION:The temperature reducing section 9 of a roller hearth continuous furnace is provided with an atmosphere regulating gas supplying means 12 and a furnace pressure detecting means 13 while the temperature rising section 7 of the same furnace is provided with a forced exhausting means 14. When a pressure in the furnace is fluctuated due to the fluctuation of the flame of a gas burner 10 in the temperature retaining section 8 of the same furnace and the like, the forced exhausting means 14 controls the discharging amount of gas in the furnace from the temperature rising section 7 whereby the flow of gas in the furnace is stabilized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous roller hearth furnace used for firing ceramic products and industrial functional ceramic products.

0002

[Prior Art] Electrically heated single furnaces have traditionally been used to fire ceramic products and industrial functional ceramic products that require firing in a non-oxidizing atmosphere. In order to improve economic efficiency, the use of continuous furnaces such as gas-heated roller hearth furnaces has recently been considered.

For this reason, for example, in a continuous roller hearth furnace for firing ceramics that requires atmosphere firing, a method is adopted in which a gas burner is fired in a reducing atmosphere in the firing section, thereby maintaining the firing section in the furnace in a reducing atmosphere. ing. However, even slight fluctuations in the flame of the gas burner can cause fluctuations in the pressure inside the furnace and the boundary position between the reducing atmosphere and the oxidizing atmosphere, so it is necessary to perform the firing and quenching processes, which have a large effect on color development, in a stable atmosphere. In such a case, there is a drawback that the quality of the fired product tends to vary.

0004

[Problems to be Solved by the Invention] The present invention was completed in order to solve the above-mentioned conventional drawbacks and to provide a gas-heated roller hearth continuous furnace that can always proceed with the cooling process in a stable atmosphere. It is what was done.

[0005]

[Means for Solving the Problems] The present invention, which has been made to solve the above-mentioned problems, is a tunnel-like furnace equipped with a large number of rollers sealed from the outside air. It is divided into a holding part and a temperature lowering part, and the temperature lowering part is provided with an atmosphere adjustment gas supply means and a furnace pressure detection means,
Furthermore, the temperature raising section is characterized by being provided with forced exhaust means for sucking the furnace gas in accordance with the furnace pressure detected by the furnace pressure detection means.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in more detail below with reference to illustrated embodiments. In FIG. 1, 1 is a tunnel-shaped furnace body with an inlet 2 at the left end and an outlet 3 at the right end.
Inside, a large number of rollers 4 are provided at a constant pitch over the entire length. As shown in FIG. 2, these rollers 4 are supported at both ends by support rollers 5, 5, and are continuously driven at a constant speed by a sprocket 6 provided at one end, and the product to be fired W placed on the upper surface thereof is driven continuously at a constant speed by a sprocket 6 provided at one end. is continuously moved from the inlet 2 to the outlet 3.

The interior of the furnace body 1 is divided into a temperature increasing section 7, a temperature maintaining section 8, and a temperature decreasing section 9 in order from the inlet side to the outlet side. The temperature raising part 7 is a part which does not have a heating means and preheats the product W to be fired by the retained heat of the combustion gas flowing from the adjacent temperature holding part 8. The temperature holding section 8 includes a large number of gas burners 10, and is a part that fires the product W to be fired based on a temperature curve determined in advance in accordance with the product W to be fired. The temperature lowering section 9 also does not have a heating means and is a section that cools the product W to be fired to around room temperature. Since the roller hearth continuous furnace of the present invention is a furnace in which the temperature dropping section 9 must be strictly maintained in a special atmosphere, a partition wall 11 is installed on the furnace wall between the temperature dropping section 9 and the temperature maintaining section 8 as shown in the figure. It is preferable to provide it in a protruding manner.

The temperature lowering section 9 is provided with an atmosphere adjusting gas supply means 12 for supplying an atmosphere adjusting gas such as an inert gas or an oxygen gas. At least the temperature decreasing section 9
The inside of the temperature decreasing section 9 can be maintained in a non-oxidizing atmosphere, or the inside of the temperature decreasing section 9 can be maintained in a strongly oxidizing atmosphere by supplying oxygen gas. Further, in the temperature decreasing section 9, a furnace pressure detection means 13 capable of detecting minute fluctuations in the furnace pressure is provided.
is installed, and detects the furnace internal pressure down to a level of, for example, 0.1 mm of water column.

On the other hand, in the part near the inlet 2 of the heating section 7,
A forced exhaust means 14 is provided for sucking in the furnace gas. The forced exhaust means 14 includes a blower 15 and a suction hole 17 connected to the suction side of the blower 15 via a valve 16 for controlling flow rate. In the present invention, the forced exhaust means 14 controls the furnace pressure detected by the furnace pressure detection means 13 described above. It is designed to suck out internal gas. That is, when an increase in the furnace pressure in the temperature lowering section 9 is detected by the furnace pressure detection means 13, the rotation speed of the blower 15 of the forced exhaust means 14 is increased by the controller 22 to increase the suction amount of the furnace gas, Conversely, when the furnace pressure in the temperature lowering section 9 decreases, the rotational speed of the blower 15 is reduced to reduce the suction amount of the furnace gas. In this embodiment, the displacement is continuously controlled by controlling the rotation speed of the blower 15 using an inverter. In addition, the temperature rising section 7
An air inlet 18 with a flow rate control valve 17 is formed in the ceiling of the chamber, and the temperature can be controlled by blowing air in with a blower 19.

As shown in FIG. 2, in order to prevent outside air from entering the furnace through the gap between the roller 4 and the furnace body 1, shielding covers 20 are provided on both sides of the roller 4 at least in required parts. At the same time, a heat-resistant seal 21 is provided around the shaft portion of the roller 4 to isolate the inside of the furnace from outside air.

[0011]

[Function] The continuous roller hearth furnace of the present invention configured as described above can be used to produce fired products such as ceramic products and industrial functional ceramic products that need to be fired in a non-oxidizing atmosphere or a strongly oxidizing atmosphere. is placed on the roller 4 from the inlet 2, and the baked product W is moved at a constant speed in the order of the temperature raising section 7, temperature holding section 8, and temperature lowering section 9 by the rotation of the roller 4,
The steps of preheating, firing, and cooling are the same as in the conventional method.

However, in the present invention, the required portions of the rollers 4 are sealed from the outside air, and an atmosphere adjusting gas supply means 12 is provided in the temperature lowering section 9 to supply inert gas or oxygen gas into the furnace. Therefore, at least the temperature decreasing section 9
The inside of the chamber is filled with an atmosphere adjusting gas, so that the cooling process can proceed in a predetermined atmosphere. Moreover, the temperature lowering section 9 is provided with a furnace pressure detection means 13, and the temperature raising section 7 is equipped with a forced exhaust means 14 for sucking the furnace gas according to the furnace pressure detected by the furnace pressure detection means 13. For example, if the pressure inside the furnace changes due to a change in the flame of the gas burner 10 in the temperature holding section 8, and the flow condition of the atmosphere in the temperature cooling section 9 changes as a result of this, the forced Since the exhaust means 14 immediately controls the exhaust amount of the furnace gas from the temperature raising section 7, the gas flow inside the furnace from the temperature lowering section 9 toward the temperature raising section 7 is always kept stable. Therefore, according to the continuous roller hearth furnace of the present invention, the cooling process can always proceed in a strictly controlled atmosphere without being affected by disturbances.

[0013]

[Effects of the Invention] As explained above, the roller hearth continuous furnace of the present invention can always proceed with the cooling process in a stable atmosphere, thereby producing ceramic products and industrial functional ceramic products of stable quality. In addition, it is possible to economically fire a large amount of products to be fired, so it can greatly contribute to the development of industry by eliminating the problems of the conventional method.

[Brief explanation of the drawing]

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

FIG. 2 is a vertical cross-sectional view of FIG. 1;

[Explanation of symbols]

1 Furnace body 4 Roller 7 Temperature rising section 8 Temperature holding part 9 Temperature-falling section 12 Atmosphere adjustment gas supply means 13　Furnace pressure detection means 14 Forced exhaust means

Claims (1)

[Claims] 1. The inside of a tunnel-shaped furnace body 1 equipped with a large number of rollers 4 sealed from the outside air is divided from the inlet side into a temperature raising section 7, a temperature holding section 8, and a temperature lowering section 9. An atmosphere adjusting gas supply means 12 and a furnace pressure detection means 13 are provided in the temperature raising section 7.
3. A roller hearth continuous furnace characterized in that a forced exhaust means 14 is provided for sucking gas in the furnace according to the furnace internal pressure detected by the furnace pressure detected by the roller hearth furnace.