JPH10153387A - Operating method for atmosphere circulation type continuous heat treatment furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance thermal efficiency by employing a down flow system for jetting the atmosphere downward through a porous plate and feeding a part of the atmosphere circulated to a specified unit band of a furnace to the unit band side on the side for loading a material to be treated thereby forming a gas flow in the furnace from the final unit band to the starting unit band. SOLUTION: A planar deflector member 41 is set, while inclining toward the side for loading a material to be treated on the bottom of a furnace located directly under the ceiling fan 4 in a unit band 40c. Consequently, a part of the atmosphere blown downward through a porous plate 7 impinges against the deflector member 41 to form a flow directed toward a unit band adjacent to the.loading side. In the unit band 40c, a material is heat treated by blowing the atmosphere at a specified temperature and migrates from the final unit band to the starting unit band and transfers the heat of the atmosphere from the material extracting side to the loading side thus balancing the heat. According to the arrangement, total fuel consumption of the facility can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating an atmosphere circulation type continuous heat treatment furnace applied to heat treatment of glass products.

[0002]

2. Description of the Related Art Conventionally, an atmosphere circulation type continuous heat treatment furnace for glass products or the like has a structure as disclosed in Japanese Patent Publication No. 2-27589. That is, as shown in FIG. 4, the heating zone 10, the soaking zone 20, the slow cooling zone 30, and the cooling zone 40 are constituted, and the processing materials are divided into belts 10, 20, 30, and 40 by a conveyor chain or a mesh belt V. It is conveyed and, during that, is subjected to a heat treatment according to a heat curve shown in FIG. In addition, each of the bands 10, 2
0, 30, and 40 are a plurality of unit bands 10a, 1
0b ..., 20a, 20b ..., 30a, 30b ... and 4
0a, 40b...

Each of the unit zones 10a, 10b,..., 20a, 20b... Of the temperature-raising zone 10 and the soaking zone 20 is, as shown in FIG. Baffle 3 and ceiling fan (circulation fan) 4
And a radiant tube burner 5 as heating means. The heating means 5 is not limited to a radiant tube burner, but may be an electric heater, a direct fire burner, or the like.

[0004] Then, the radiant tube burner 5 is burned and the ceiling fan 4 is rotated to circulate the furnace atmosphere through a circulation path 6 formed between the furnace wall 2 and the partition wall 3 as shown by an arrow. The atmosphere inside the furnace heated by the radiant tube burner 5 and heated to a predetermined temperature is sucked and agitated by the ceiling fan 4 and sprayed downward from the perforated plate 7 to be conveyed by a conveyor chain or a mesh belt V (shown in FIG. Is heat-treated.

The unit zones 30a, 3a of the slow cooling zone 30
As shown in FIG. 7, reference numerals 0b... Denote the air supply duct 31 for introducing the atmosphere above the partition wall 3 and the exhaust duct for discharging the atmosphere in the furnace, in addition to the configuration of the unit zones of the warming zone 10 and the soaking zone 20. The furnace circulating atmosphere temperature is adjusted to a predetermined temperature by adjusting the combustion amount of the radiant tube burner 5, the amount of air introduced from the air supply duct 31, and the amount of exhaust of the furnace atmosphere from the exhaust duct 32. I do.

The unit bands 40a, 40 of the cooling zone 40
b are unit bands 30 of the slow cooling zone 30 as shown in FIG.
As apparent from comparison with a, 30b,..., the only difference is that there is no radiant tube burner 5 and the furnace body 1 does not have a heat insulating structure.

Then, each unit band 10a, 10b...
0a, 20b ..., 30a, 30b ..., 40a, 40b ...
The ambient temperature is independently controlled by a thermocouple (not shown) provided in each unit zone, and is maintained in a state where furnace air does not flow in or out between adjacent unit zones. That is, in the slow cooling and the cooling, the temperature control is performed while maintaining the supply amount and the exhaust amount of the cooling air in the unit band substantially the same.

[0008]

As described above, in the system in which the temperature in each unit zone is completely independently controlled, there is no flow of furnace gas, and the high-temperature furnace gas in the solitary zone 20 has a heat source in the heating zone 10. And the thermal efficiency is poor. Therefore, the present inventors examined whether the thermal efficiency could be improved by moving the furnace gas from the unit zone on the end side of the furnace toward the unit zone on the start side. As a result of the study, as shown in FIG. 9, when the furnace air flow rate is a predetermined amount, for example, 60 m ³ / min in FIG. 9, the total required calorific value of the furnace can be minimized, and about 20% of the calorific value is smaller than the conventional method. It has been found that the thermal efficiency can be improved accordingly. FIG. 9 is obtained by simulating the heat balance using the furnace air flow rate as a variable. Accordingly, an object of the present invention is to provide a method of operating a conventional atmosphere circulation type continuous heat treatment furnace which has good thermal efficiency by adding a simple structure to a conventional atmosphere circulation type continuous heat treatment furnace.

[0009]

In order to achieve the above object, a method for operating an atmosphere circulation type continuous heat treatment furnace according to the present invention has a temperature rising zone, a soaking zone, a slow cooling zone, and a cooling zone. In an atmosphere circulation type continuous heat treatment furnace having a plurality of unit zones forming an atmosphere circulation path by a ceiling fan and a furnace inner partition in a zone, a down flow system in which atmosphere circulation is jetted downward from a perforated plate, and A part of the circulating atmosphere flows into a predetermined unit zone into an adjacent unit zone on the side where the processing material is charged, so that a furnace gas flow from the last unit zone to the start unit zone is formed in the furnace. Further, a part of the circulation atmosphere may be caused to flow into the adjacent unit zone by providing a drift member at least in the hearth portion of the final unit zone. Furthermore, a part of the circulating atmosphere may be caused to flow into the adjacent unit zone side on the processing material charging side by providing a drift plate below the perforated plate of at least the final unit zone. By inclining the perforated plate, a part of the circulating atmosphere may be caused to flow into the adjacent unit zone side on the processing material charging side.

[0010]

Next, an embodiment of the present invention will be described. The atmosphere circulation type continuous heat treatment furnace to which the present invention is applied is basically the same as that of the above-described conventional structure, so that the overall configuration diagram is omitted. However, a part of the circulating atmosphere in a predetermined unit zone of the furnace, for example, in the last unit zone of the cooling zone 40 is caused to flow into the adjacent unit zone on the side where the processing material is charged, and the furnace gas is entirely moved from the last unit zone to the starting unit zone. It flows to the unit band. Then, the temperature of the circulating atmosphere blown to the processing material in each unit zone is controlled to a predetermined temperature by a thermocouple or the like as in the related art.

As a first embodiment of this drift forming means, as shown in FIG. 1, the unit zone 40c is inclined at the furnace bottom located just below the ceiling fan 4 with respect to the processing material charging side. A plate-shaped drift member 41 is provided. A part of the atmosphere blown downward from the perforated plate 7 by the installation of the drift member 41 collides with the drift member 41 and forms a flow to the adjacent unit zone 40b on the charging side.

FIG. 2 shows a second embodiment, in which a perforated plate 7 is provided.
Drift member 4 comprising a plurality of guide plates rotatable below
1A is provided to allow a part of the atmosphere blown downward from the perforated plate 7 to flow toward the adjacent unit zone 40b. FIG. 3 shows FIG.
In this embodiment, the perforated plate 7 is inclined such that the processing material extraction side is low and the charging side is high so that the perforated plate 7 itself functions as the drift member 41B.
Since the distance between the perforated plate 7 and the furnace bottom is smaller on the right side than on the left side, when the atmosphere blows out from the perforated plate 7, the right side has a higher pressure than the left side.
It will flow to the 0b side.

It is a matter of course that the drift members 41, 41A and 41B may be installed in other unit zones depending on the length of the heat treatment furnace and the like. Further, the furnace air flow rate for obtaining the minimum total required heat amount also differs depending on the heat treatment furnace, so that the furnace air flow rate corresponding to the applicable heat treatment furnace is used.

[0014]

As is apparent from the above description, according to the present invention, in each unit zone, an atmosphere at a predetermined temperature is blown to the processing material to heat-treat the processing material, while the atmosphere in the furnace is the final unit. Move from the band to the start unit band,
In other words, there is an effect that the amount of heat of the atmosphere on the processing material extraction side is moved to the charging side to perform the heat balance, and the fuel consumption of the entire facility can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a cooling zone for carrying out the operation method of the present invention.

FIG. 2 is a sectional view of a cooling zone showing another embodiment for carrying out the operation method of the present invention.

FIG. 3 is a sectional view of a cooling zone showing another embodiment for carrying out the operation method of the present invention.

FIG. 4 is a schematic plan view of a conventional atmosphere circulation type continuous heat treatment furnace.

FIG. 5 is a heat curve of the atmosphere circulation type continuous heat treatment furnace of FIG.

FIG. 6 is an enlarged cross-sectional view of a warming zone and a tropical zone of FIG.

FIG. 7 is an enlarged sectional view of the slow cooling zone of FIG.

FIG. 8 is an enlarged sectional view of the cooling zone of FIG. 4;

FIG. 9 is a graph showing the relationship between the furnace air flow rate and the total required heat amount in FIG.

[Explanation of symbols]

1 furnace main body, 2 furnace wall, 3 partition wall (baffle), 4 ceiling fan, 5 heating means, 6 circulation circuit, 7 perforated plate, 1
0 to warming zone, 20 to soaking zone, 30 to slow cooling zone, 40 to cooling zone, 10a, 10b ..., 20a, 20b ..., 30a, 3
0b ..., 40a, 40b ... ~ unit band, 31 ~ air supply duct, 32 ~ exhaust duct, 41, 41A, 41B ~ drift member, V ~ conveyor chain.

Claims (4)

[Claims] An atmosphere circulation type continuous heat treatment having a temperature rising zone, a soaking zone, a slow cooling zone, and a cooling zone, and having a plurality of unit zones in each zone forming an atmosphere circulation path by a ceiling fan and a furnace inner partition. In the furnace, a down flow method in which the atmosphere circulation is ejected downward from the perforated plate, and a part of the circulating atmosphere is caused to flow into a predetermined unit zone of the furnace into an adjacent unit zone on the side where the processing material is charged, and the inside of the furnace is Forming a furnace gas flow from a final unit zone to a starting unit zone. 2. The continuous atmosphere circulating system according to claim 1, wherein a part of the circulating atmosphere is caused to flow into the adjacent unit zone by providing a drift member at least in the hearth portion of the final unit zone. Operating method of heat treatment furnace. 3. The method according to claim 1, wherein a part of the circulating atmosphere is caused to flow into the adjacent unit zone on the charging side of the processing material by providing a drift member at least below the perforated plate of the final unit zone. Operating method of continuous circulation heat treatment furnace of atmosphere circulation type. 4. The atmosphere circulation according to claim 1, wherein at least a part of the circulation atmosphere is caused to flow into the adjacent unit zone on the side where the processing material is charged by inclining at least the perforated plate of the final unit zone. Operating method of continuous heat treatment furnace.