JPH08219649A - Gas sealing device for movable hearth type furnace - Google Patents

Abstract

PURPOSE: To prevent the overheat, evaporation, ignition of sealing liquid or the precipitation of carbon by a high-temperature atmosphere gas in a furnace. CONSTITUTION: A gas sealing device for a movable hearth type furnace comprises a sealing plates 8, 9 so fixed to be suspended at the home position 1a and the movable hearth 4 of a furnace body 1 and sealing liquid 14 filled in a liquid tank 13 and dipped with the lower ends of both the plates 8, 9 therein, wherein nitrogen gas is supplied from the position 1a of the body 1 so as to store the nitrogen gas in a gap between both the plates 8 and 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas sealing device between a movable floor part and a stationary part in a movable hearth type furnace such as a rotary hearth type furnace, a walking hearth furnace or a movable hearth movable batch furnace. Is.

[0002]

2. Description of the Related Art In a movable hearth type furnace such as a rotary hearth type furnace in which a material to be heated is moved in the furnace, or a furnace body is movable for carrying in and out, a movable floor part and a stationary bed are fixed. Conventionally, a liquid-sealing type gas sealing device is provided in order to prevent the atmospheric gas in the furnace from leaking out from the gap between the parts and the outside air from entering. As is well known, this is achieved by fixing seal plates to the movable floor portion and the stationary portion in a skirt-like manner, and water or flame-retardant in a gutter-shaped liquid tank provided along the floor movable direction. The oil is stored and the lower ends of both seal plates are immersed in this liquid to perform gas sealing without impeding the movement of the movable floor.

[0003]

In the movable hearth type furnace described above, when the temperature inside the furnace is high, the atmospheric gas in the furnace reaches the seal liquid surface through the gap between the seal plates, and the temperature of the seal liquid is high. It will be heated to. For this reason, the sealing liquid may evaporate in a short time, or if oil is used, it may catch fire and become dangerous. Further, when the inside of the furnace is a carburizing atmosphere gas at a high temperature, the temperature of the atmosphere gas is lowered at the seal portion, and a large amount of carbon is caused to be broken out, which causes a malfunction.

[0004]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and seal plates are fixed to the stationary portion and the movable floor portion of the furnace body so as to face each other with a gap therebetween. A gas sealing device for a movable hearth type furnace in which the lower ends of both sealing plates are immersed in a liquid tank filled with sealing liquid,
It is characterized in that the nitrogen gas is supplied from the stationary portion side of the furnace body so that the nitrogen gas stays in the gap between the both seal plates.

[0005]

With the retention of nitrogen gas, it becomes difficult for the high temperature atmosphere gas in the furnace to reach the level of the sealing liquid, so that the carbon is prevented from protruding and the sealing liquid is prevented from overheating.

[0006]

Embodiments of the present invention will be described below with reference to the drawings for a rotary hearth furnace. FIG. 1 shows a vertical cross section of this rotary hearth type furnace. In the figure, 1 is a cylindrical furnace body supported by a machine frame 2 and 3 is a device for heating objects installed on one side of the furnace body 1. The inlet / outlet port 4 is a movable floor supported by a rotary shaft 5 at the center of the furnace body 1 so as to rotate in a horizontal plane, H is an object to be heated placed on the movable floor 4, and 6 is a heat source. Is a radiant tube heater, and 7 is a fan for stirring the atmosphere in the furnace.

As shown in FIG. 2 and FIG. 3, sealing plates 8 and 9 are attached to the peripheral portion of the movable floor 4 and the stationary portion 1a of the furnace body 1 facing the peripheral portion by bolts 10 and 11, respectively. It is fixed in a hanging shape. And inside the machine casing 2, shelves 12
And the liquid tank 13 is arranged on the shelf 12. The liquid tank 13 is formed in an annular shape having substantially the same diameter as the outer diameter of the movable floor 4, and a seal liquid 14 made of flame-retardant oil is stored in the liquid tank 13. The lower ends of both seal plates 8 and 9 are contained in the seal liquid 14. Is soaking.

Reference numeral 15 is a water cooling jacket formed so as to surround the liquid tank 13, and the water supply port 1 is provided in the water cooling jacket 15.
6. Cooling water is taken in and out from the drain port 17, respectively, and the liquid tank 13
The seal liquid 14 therein is cooled. In addition, the sealing liquid 14
Is supplied from the tank 18 through a strainer 19, a cooler 20, a pump 21 and a check valve 22, and the seal liquid 14 overflowing from the liquid tank 13 naturally flows through the return pipe 28 into the tank 18 to be directly cooled. It is like this. Reference numerals 23 and 24 denote covers made of stainless foil fixed to both side plates of the liquid tank 13. The upper ends of the covers 23 and 24 are elastically brought into contact with the outer side surfaces of both seal plates 8 and 9. The sealing liquid 14 is dustproof and flameproof by covering the upper part of the liquid tank 13 with the cover.

Therefore, an air supply port 25 is opened in the seal plate 9 on the stationary portion 1a side, a hose 27 is branched from an air supply pipe 26 connected to a nitrogen gas supply source, and both seal plates 8 are passed through the hose 27. , 9 is supplied with nitrogen gas.
The air supply pipe 26 is provided so as to surround the entire circumference of the furnace body 1, a plurality of hoses 27 are provided in the air supply pipe 26 at equal intervals, and a plurality of air supply ports are formed in the seal plate 9 at regular intervals. Two
Nitrogen gas is supplied between the seal plates 8 and 9 more uniformly than the number 5. In this way, the nitrogen gas supplied between the seal plates 8 and 9 is sealed by the seal liquid 14 in the lower part and is retained in the upper part because there is a high temperature atmosphere gas having a lower specific gravity. .

[0010]

As described above, the gas sealing device of the present invention is
Retaining nitrogen gas in the gap between the seal plates prevents the high-temperature furnace atmosphere gas from reaching the seal liquid directly, preventing the seal liquid from overheating and causing an accident due to its evaporation or ignition. It has a beneficial effect such as the prevention of carbon protrusion and the like.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a rotary hearth type furnace showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged view of a main part of FIG.

[Explanation of symbols]

 1 Furnace Body 1a Stationary Part 4 Movable Floor 8, 9 Seal Plate 13 Liquid Tank 14 Seal Liquid 15 Water Cooling Jacket 25 Air Supply Port 26 Air Supply Pipe 27 Hose

Claims (1)

[Claims] 1. Sealing plates are fixed to the stationary portion and the movable floor portion of the furnace body so as to face each other with a gap, and the lower ends of both sealing plates are placed in a liquid tank filled with the sealing liquid. A gas sealing device for a movable hearth furnace which is immersed, wherein the nitrogen gas is supplied from the stationary portion side of the furnace body so that the nitrogen gas stays in the gap between the sealing plates. Gas seal device for floor furnace.