JPH0776677B2 - Clean heating furnace - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heating furnace intended for use in those requiring cleanliness of furnace gas, such as firing of New Ceramics and manufacturing of cathode ray tubes.

[Prior art and its problems] Conventionally, in addition to dust that flows from the outside into the heating furnace, the heat insulating material that constitutes the furnace wall, such as ceramic wool and rock wool, expands and contracts with heating and cooling. There was a lot of pollution due to scattered dust or dust generated by oxidation of metal parts such as conveyor chains in the furnace. However, in the case of firing New Ceramics or the like used for a sensor or heating a Braun tube, there is a problem that even a small amount of dust adheres to a heated object to cause a defective product, resulting in poor yield.

[Means for Solving the Problems] The present invention is intended to solve the above problems. A furnace wall is constructed from a wool-like heat insulating material such as ceramic wool and rock wool, and a radiant tube burner or an electric furnace is installed in the furnace. A heating furnace equipped with a heat source such as a heating element, which is equipped with an electric dust collector in which the gas in the furnace circulates, and which collects wool-like floating dust scattered from the furnace wall by the electric dust collector It is a heating furnace.

Next, one embodiment of the present invention will be described for a continuous furnace.

FIG. 1 shows a cross-sectional view of the heating zone of this coupled furnace. In the figure, 1 is a furnace body constructed by a furnace wall made of wool-like heat insulating material such as lamic wool and rock wool, 2 is a circulation fan provided at the ceiling of the furnace body, and 3 is a furnace gas below the circulation fan. Baffle plates for forming ventilation passages, 4, 4 are radiant tube burners arranged in the gap between the outer side and the side wall of the baffle plate, 5 are for supporting the object 6 to be heated by a tray, mesh belt 7 The transfer apparatus moved is shown.

An electric dust collector 18 is provided on the side wall of the furnace body 1. That is, openings 8 and 9 are opened at the upper and lower positions of the side wall, and a U-shaped circulation path 10 that connects the openings 8 and 9 is formed outside the furnace by a heat insulating material, and an electrode is provided in a vertical portion of the circulation path 10. A conductive wire (11) is hung from the insulator (12), and a dust pot (13) is provided below it. Reference numerals 14 and 15 are manual shutters that can open and close the openings 8 and 9. A hose 17 of a vacuum suction device 16 is connected to the dust port 13.

The electrostatic precipitator 18 is provided not only in the heating zone of the continuous furnace but also in the soaking zone and the cooling zone as shown in FIG.

In the clean heating furnace configured as described above, the gas inside the furnace is circulated by the rotation of the circulation fan 2 as shown by the broken line arrow in FIG. The heating object 6 is heated to a desired temperature. Then, as shown in the temperature-time schedule in FIG. 3, soaking and cooling are performed by moving the soaking zone and the cooling zone. A part of the gas in the furnace is circulated 10 from the opening 8.
It flows into the furnace, flows down through the circulation path, and returns into the furnace through the opening 9. At that time, due to the voltage of 1 to 20,000 volts applied to the electrode wire 11, the suspended dust in the gas in the furnace is charged and can be collected in the dust pot 13. For this reason, the inside of the furnace can be maintained in a clean atmosphere without floating substances.

The dust accumulated in the dust pot 13 is sucked up by the vacuum suction device 16 and discharged as necessary. Manual shutter at that time
Keeping 14,15 closed prevents dust from re-scattering in the furnace.

In this embodiment, the gas in the furnace is circulated in the circulation path 10 by the wind pressure of the circulation fan 2. However, a small fan for circulation may be provided separately, or in the circulation path 10. Alternatively, a small heater may be provided to circulate the in-furnace gas due to its draft effect.

[Effects of the Invention] As described above with reference to the embodiments, the clean heating furnace of the present invention ensures that the dust that is scattered from the wool-like heat insulating material such as the ceramic wool that constitutes the furnace wall is dispersed by the electrostatic precipitator. The dust can be prevented from adhering to the object to be heated as much as possible because it can be collected in the furnace and the inside of the furnace can be kept clean. It is useful for improving the yield of heat treatment.

[Brief description of drawings]

The drawings show one embodiment of the clean heating furnace of the present invention. FIG. 1 is a transverse sectional view, FIG. 2 is a plan view, and FIG. 3 is a diagram showing a temperature-time schedule. 4 ... Radiant tube burner, 5 ... Transfer device, 6
…… Heated object, 8, 9 …… Opening, 10 …… Circulation path, 11 …… Electrode wire, 14, 15 …… Shatter, 18 …… Electrostatic precipitator.

Claims (1)

[Claims] 1. A heating furnace in which a furnace wall is constructed from a wool-like heat insulating material such as ceramic wool and rock wool, and a heat source such as a radiant tube burner or an electric heating element is provided in the furnace, in which furnace gas is circulated. Attach an electric dust collector to
A clean heating furnace characterized in that wool-like floating dust scattered from the furnace wall is collected by the electrostatic precipitator.