Telescopic type maze isolation nitrogen interlocking control system operation method for hot galvanizing vertical annealing furnace

Abstract

The invention discloses a telescopic type maze isolation nitrogen interlocking control system for a hot galvanizing vertical annealing furnace. The annealing furnace is partitioned. Zones are separated through partitions. Gaps are reserved between the partitions to allow a steel strip to pass through. A telescopic isolation device is arranged between the gaps. Signal interlocking control is builtbetween the isolation device and an interlocking protection control module as well as a signal acquisition module. When one zone of the annealing furnace sends an abnormal signal, the isolation deviceacts to close the gaps, thus the abnormal zone is isolated, and the normal zones keep positive pressure. The telescopic type maze isolation nitrogen interlocking control system has the beneficial effects that through the structure of zone isolation and the telescopic type isolation device, segmented sealing is achieved, in-furnace pressure of all other zones can be kept in time, and thus fault loss is lowered to the minimum.

Description

technical field [0001] The invention belongs to production equipment in steel mills, and in particular relates to an operation method for a nitrogen interlock control system of a hot-dip galvanizing vertical annealing furnace, and protection equipment for protecting the furnace temperature of the annealing furnace and the plate temperature under high-temperature conditions. Background technique [0002] The vertical annealing furnace uses radiant tubes for radiant heating under the protection of nitrogen and hydrogen protective gas. The leakage of the sealed annealing furnace body is particularly serious. After a leak occurs in a certain section of the annealing furnace, timely and effective measures to maintain pressure cannot be adopted or measures must be taken. When a large amount of cold air enters the furnace, which causes negative pressure in the annealing furnace, the accident magnifies, damages important equipment and sensors in the annealing furnace, and causes imme...

AI Technical Summary

Problems solved by technology

[0006] Annealing furnace rollers are subject to uneven thermal expansion and contraction deformation, resulting in bending or irregular deformation, and permanent damage such as tungsten carbide material falling off the roller surface

[0007] The radiant tubes of the annealing furnace are deformed and cracked by heat expansion and contraction. As an important heating equipment inside the annealing furnace, if the gas leaks, it will cause an explosion accident in the annealing furnace. The number of radiant tubes in the annealing furnace is generally more than 100, and inspection or replacement needs to be stopped. Gas, dismantle and connect the gas supply pipeline, the construction volume is large, and the replacement and detection time is long

[0008] What is more serious is that the steel strip in the annealing furnace is rapidly oxidized under high temperature conditions, producing a large amount of oxide scale, which is concentrated on the upper surface of the strip steel and adheres to the surface of the rollers, and generates relative friction with the running strip steel, causing the furnace rolls to The tungsten carbide coating on the surface falls off, and the unprotected tungsten carbide coating directly scratches the substrate of the roll surface, and the roughness of the roll surface is damaged. As long as it occurs once, the damage caused by not being found in time or not being shut down in time will increase over time. Extended and enlarged, the iron oxide scale in the annealing furnace falls to the bottom of the furnace after being produced, which is mainly related to the process design of the vertical annealing furnace. The furnace rollers are arranged up and down, and the strip steel is vertically arranged in the furnace. The length of the strip steel is generally 400 More than one meter, a large number of oxide scales are concentrated on the bottom of the furnace. With the operation of the rollers and the strip, they are concentrated in the segmented area and piled up at the junction of the preheating section, heating section, slow cooling section, rapid cooling section and horizontal turning section. Severe belt breakage accidents

[0009] A large amount of iron scale produced in the annealing furnace affects the accuracy of the detection element, and a large amount of iron oxide dust adheres to the detection element in the furnace. Instruments such as gas analyzers and gas analyzers have a greater impact. If problems arise, these instruments and meters need to be checked again. The inspection and replacement cycle is long and cleaning is difficult.

The oxide scale will cause insulation drop to the exposed electric heater, short-circuit trip accident, and cannot be put into use. It is necessary to clean the oxide scale between the electric heaters

A large amount of oxidized iron scale adheres to the inner wall of the furnace. It is difficult to clean under the unfavorable conditions of small internal space and a height of more than 30 meters. The safety risk in the cleaning process is relatively large.

A large amount of iron oxide belt produced in the annealing furnace enters the zinc pot and adheres to the strip steel, which will cause damage to subsequent production equipment, such as rubber squeeze rollers, skin pass mill work rolls, tension leveler roll systems, and roller coaters. Scratches or indentations occur on the surface of coating rollers, etc., resulting in periodic product defects

The damaged rollers need to be replaced directly, and the old rollers are re-grinded and cut

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