JPS6249186A - Method of operating oxide-film forming treating furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of operating a processing furnace for producing a slimy oxide film, which uniformly forms an oxide film on the surface of electric parts such as shadow masks and motor cores, and other processing materials. It is.

[Prior Art] FIG. 2 schematically shows a mesh belt conveyance type continuous processing furnace that has been conventionally used to generate an oxide film on a shadow mask for a color television cathode ray tube. In the figure, a is the furnace main body, b is the charging throat extending from one end of the furnace, C is the extraction throat extending from the other end, and d is an endless mesh belt for conveying the processed material.

Denoted at e and e' are rolls for turning. In this case, the material to be treated is loaded on the mesh belt d, carried into the furnace body a through the charging throat b, and extracted out of the furnace through the extraction throat C.

Note that a heat source such as an electric heater is provided inside the charging throat b and the furnace body a. Further, a heat-generating gas or an oxidizing gas such as steam is supplied to the furnace body a from a gas generator f. gl; H'i Exhaust gas pipe installed at approximately the middle length of the human throat b, h is the outlet of the extraction throat C.
From the exhaust gas pipe 2, the atmospheric gas flowing from the furnace body a and the atmosphere entering from the charging port of the charging throw +-b are combined and discharged from the IJL. I'm trying to make it happen.

However, in such a conventional oxidized 1 skin production processing furnace (1
As will be described next, there is a problem in that dew condensation tends to form on the surface of the material to be treated when it is loaded, and if it is heated as it is, it will cause stains. That is, the treated material charged into the charging throat is preheated by a heater and is conveyed toward the furnace body a while gradually raising the temperature. It is necessary to heat the treated material to a temperature higher than the dew point of the atmospheric gas, but in this case, the atmospheric gas and atmosphere are discharged through the exhaust gas pipe g, so the amount of atmospheric gas and the invading atmosphere are If the balance with the amount is poor, the boundary is not defined and adjustment is extremely difficult and short, resulting in frequent condensation and defective products. Further, since the dew point of the atmospheric gas is not constant and is, for example, 35 to 60° C. for exothermic gas and about 100° C. for steam, the required length of the charging throat varies depending on the type of n1lH gas. For this reason, in the past, for example, equipment had to be manufactured exclusively for exothermic gas or equipment for steam, resulting in a problem of high equipment costs.

[Means for Solving the Problems] The present invention takes the following measures to solve the above problems. That is, in the method of operating the oxide film production processing furnace according to the present invention, a front chamber is formed at the charging port of the furnace body filled with atmospheric gas, and the dew point is lower than the temperature of the processing material charged into the front chamber. The preheating gas is filled in the front chamber to preheat the treated material in the front chamber to a temperature higher than the dew point of the atmospheric gas in the furnace body, and then the treated material is transferred to the furnace body. It is something.

[Example] The oxide film production furnace shown in Fig. 1 is of a roller hearth type, and 1 is a furnace body consisting of a heating and soaking zone 2 and a cooling zone 3, 4 is a partition door between both zones, and 5 is a This is a roller that conveys the processing material A. 6 has partition walls 7 and 8 at the charging port of the furnace body 1.
9 is a front chamber defined by partition doors 10 and 11 at the extraction port of the furnace main body 1; 12 is a charging table.

13 is an extraction table. 14 is a radiant tube burner provided in the heating and soaking zone 2, and 15 is an electric heater provided in the front chamber 6. Exothermic gas is supplied to the heating and soaking zone 2 and the cooling zone 3 of the furnace body 1 from a gas generator [16] through a pipe 17, and the furnace body is filled with the atmospheric gas. The dew point of this atmospheric gas is 40 to 4 in the case of exothermic gas with a -carbon oxide concentration of 1.5 to 2%.
In the case of steam, it is about 100°C as mentioned above. 18 is a blower for supplying air to the front chamber 6, and 19 is a blower for supplying air to the rear chamber 6.

When charging the room-temperature processing material A on the charging table 12 into the heating and soaking zone 2 of the furnace body 1, the front chamber 6 is first filled with preheating gas. This preheating gas may be any gas that is inert and has a dew point lower than the temperature (room temperature) of the treated material A before charging, and specifically, nitrogen gas, air, etc.
Of course, considering the cost, a dry atmosphere (with a dew point below the room temperature of the treated material A) is preferable, so air is supplied from the blower 18 to fill the front chamber 6. Then, the partition 7 is opened, the processing material A is charged into the front chamber 6, the partition door 7 is closed, and the processing material A is preheated by the electric heater 15.

After the material to be treated in the front chamber 6 has been preheated to a temperature higher than the dew point of the atmospheric gas in the furnace body 1, the partition door 8 is opened and the material to be treated is transferred to the heating and soaking zone 2 of the furnace body 1. . Then, the partition door 8 is closed, the partition door 7 is opened, and the material to be subsequently treated is charged into the front chamber 6 and similarly preheated, after which the partition door 8 is opened and the material is transferred to the furnace main body 1. The treated material A transferred into the furnace body 1 is further heated in an atmospheric gas in a heating and soaking zone 2 to form a desired oxide film on the surface. The reinstatement processing material A is partition B
4 is opened and transferred to the cooling zone 3, where it is cooled in an atmospheric gas;
Further, it passes through the rear chamber 9 and is extracted onto the extraction table 13.

The rear chamber 9 is provided to prevent atmospheric gas from leaking in the cooling zone 3, and air for gas replacement is supplied from the rib blower 19.

In this embodiment, an electric heater 15 is provided in the front chamber 6 for preheating the processing material A in the front chamber 6.

Such a heat source is not necessarily provided in the front chamber 6; for example, a heat source may be provided in the air supply path of the blower 18 to raise the temperature of the preheating gas and spray it onto the processing material A. . In that case, a heat exchanger (not shown) can be installed in the air supply system, and the exhaust gas from the furnace body 1 can be passed through the heat exchanger to effectively use the exhaust heat of the exhaust gas for preheating, thereby saving energy. .

[Effects of the Invention] As explained below with respect to the 1-length flow side, the present invention has the advantage of preheating the treated material to a temperature higher than the dew point of the furnace atmosphere gas in the compartmented front chamber. It is possible to reliably prevent dew condensation and easily avoid quality defects caused by stains, and also to easily respond to dew point fluctuations due to changes in the type of gas in the furnace atmosphere by simply changing the preheating temperature in the front chamber. It is possible to deal with this by having a dedicated furnace for each atmospheric gas (
However, it often has remarkable effects such as reducing equipment costs.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of an oxide film forming processing furnace illustrating an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view schematically showing a conventional oxide film forming processing furnace. Δ... Treated material, 1... Furnace body, 6... Front chamber, 7° 8... Partition door, 15... Electric ripening heater, 1
6...Gas generator, 18...Blower. Procedural amendment October 11, 1985 Michibu Uga, Commissioner of the Patent Office, 1985 Patent Application No. 189125 2, Title of invention: Method of operating an oxide film forming treatment furnace 3, Relationship with the person making the amendment Patent Name of applicant: Daido Steel Co., Ltd. 4, Agent: 5, Date of amendment order: Voluntary action: 6, Number of inventions increased by amendment: 7, Subject of amendment: Detailed explanation of the invention in the specification. 8. Contents of amendment

Claims (1)

[Claims] A front chamber is formed at the charging port of the furnace body filled with atmospheric gas, and the front chamber is filled with a preheating gas whose dew point is lower than the temperature of the processing material charged into the front chamber. 1. A method for operating a furnace for producing an oxide film, characterized in that the treated material is preheated to a temperature equal to or higher than the dew point of atmospheric gas in the furnace body, and then the treated material is transferred to the furnace body.