CN216718984U - Micro-positive pressure detection device for protective atmosphere electroslag furnace - Google Patents

Abstract

The utility model provides a micro-positive pressure detection device for a protective atmosphere electroslag furnace, which is used for ensuring the required inert atmosphere in the furnace. By aiming at the original equipment: the improvement of the sealing part, the pressure testing device part and the control part establishes a device system capable of controlling and detecting the atmosphere in the furnace, and the proper opening degree of the dust exhaust valve can be controlled according to the actual pressure condition in the protective cover, so that the inert gas atmosphere in the furnace can be ensured, and the proper pressure can be ensured to avoid sealing damage and arcing between all conductive contact surfaces. The utility model has the beneficial effects that: argon gas is still filled at the flow of 200L/min before arcing, the pressure value in the furnace is monitored in the process, after the micro-positive pressure requirement of 0.4bar-0.6bar is met, the opening angle of the dust exhaust automatic valve is automatically adjusted to be small by the system, the dust exhaust valve is not completely closed, the function of discharging flue gas is still kept, meanwhile, the pressure in the furnace is also reduced, and the argon gas consumption is reduced.

Description

Micro-positive pressure detection device for protective atmosphere electroslag furnace

Technical Field

The utility model belongs to a supplementary function device of a protective atmosphere electroslag furnace, and particularly relates to a micro-positive pressure detection and control system of the protective atmosphere electroslag furnace, which is used for ensuring the smelting environment of inert gas in the electroslag furnace and improving the quality of an electroslag ingot.

Background

With the improvement of the quality requirement of special steel electroslag ingots, the protective atmosphere constant melting speed electroslag furnace gradually replaces a non-protective atmosphere common electroslag furnace. The electroslag furnace with protective atmosphere needs to be filled with inert gas (such as argon) with a certain flow rate in the furnace to remove air in the furnace, maintain the gas atmosphere in the furnace and reduce harmful oxidation reaction. The current operation mode is that a dust exhaust valve is completely opened for filling a large amount of argon in a large amount of gas filling stage, the discharged air completes gas replacement as soon as possible, and the opening angle of the valve is manually adjusted to be small after the stable smelting stage is started. The manual valve adjusted according to experience can only meet general working conditions, when the electrode or slag discharge amount is large, the adjusted opening degree cannot be ensured to be a proper angle, the opening amount of the manually adjusted valve is large, the use amount of argon is increased, and the smelting cost is increased; the pressure in the furnace is high due to the small opening amount, the sealing damage of the dust cover is caused for many times, the micro-positive pressure atmosphere in the furnace cannot be ensured, and the large-current contact element is damaged.

For example, as shown in fig. 1, in order to ensure an inert atmosphere in a furnace, the original design fully considers an electroslag furnace pull rod (3), a pull rod sliding contact part (1), an atmosphere protective cover and crystallizer seal (7), and an atmosphere protective cover and pull rod seal (2), wherein the atmosphere protective cover and crystallizer seal (7) are asbestos seals, and the atmosphere protective cover and pull rod seal (2) are high-temperature-resistant asbestos seals. However, the pressure in the furnace is higher due to the fact that the opening amount of the manual valve is too small, the sealing of the original electroslag furnace in the protective atmosphere is very easy to damage in a high-temperature dusty environment, after the electroslag furnace is damaged, gas leaks from the atmosphere protective cover and the pull rod sealing (2) and the atmosphere protective cover and the crystallizer sealing (7), leaked gas and dust containing fluoride accumulate at the position of the pull rod sliding contact part (1), the pull rod sliding contact part (1) is an electrode current conducting access point, a plurality of carbon brushes are tightly attached to the pull rod (3) under the action of a spring, the pull rod (3) is guaranteed to be still in good contact conduction in a sliding state, dust is collected between the pull rod (3) and the carbon brushes to cause poor sliding contact, arcing discharge is caused, and a large-current contact element is damaged. The original design of the oxygen content analyzer in the detection protective cover (6) has the advantages that due to the high-temperature dusty environment, a filter element is easy to block, a sensor is easy to damage, the measured value is often inaccurate or data cannot be normally detected, and the atmosphere state in the furnace is unknown; in this case, the contact surface row (5) of the conductive flange is frequently in poor contact and damaged by arcing.

Therefore, a device system capable of controlling and detecting the atmosphere in the furnace is needed, which can control the opening degree of the proper dust exhaust valve according to the actual pressure condition in the protective cover, thereby not only ensuring the inert gas atmosphere in the furnace, but also ensuring proper pressure to avoid sealing damage and arcing between all conductive contact surfaces. At present, no data introduction is specially used for a micro-positive pressure detection and control device system of a protective atmosphere electroslag furnace.

Disclosure of Invention

The utility model provides a micro-positive pressure detection device for a protective atmosphere electroslag furnace, which is used for ensuring the required inert atmosphere in the furnace.

The specific technical scheme is as follows:

the system for detecting and controlling the micro-positive pressure of the protective atmosphere electroslag furnace consists of a sealing device of the electroslag furnace, a pressure detection valve, a dust exhaust valve and an electrical control PLC module.

As shown in fig. 1, firstly, ensuring the sealing performance of the furnace platform, replacing and repairing an atmosphere protection cover and a pull rod seal (2) of the electroslag furnace (see fig. 2), and an atmosphere protection cover and a crystallizer seal (7) (see fig. 3); the lower part of an atmosphere protection cover (6) is provided with a hole, a pressure testing device (11) is additionally arranged to detect the pressure of inert gas in the furnace, the most important thing for ensuring the proper protection atmosphere of the electroslag furnace is the atmosphere at the upper part of the slag liquid level, the detection point needs to detect the protection gas atmosphere at the upper part of a molten pool as far as possible, the position 300mm above the lower edge of the protection cover is selected, and the hole, a welding flange and a matched installation are properly sealed.

The dust exhaust valve of the dust exhaust port (4) can adjust the opening amount according to different smelting stages and actual pressure conditions in the furnace. As shown in fig. 4, a dust exhaust automatic valve (14) is added in front of an original main dust exhaust manual valve (main valve) (15) on a dust exhaust pipeline, and the dust exhaust automatic valve (14) is an angle control valve; and a dust-discharging manual valve (bypass valve) (13) is arranged, the dust-discharging manual valve (bypass valve) (13) and the dust-discharging automatic valve (14) are connected in parallel, and the gas pressure in the furnace reaches the set micro-positive pressure value of 0.4-0.6 bar.

As shown in fig. 5, the pressure signal detected by the pressure testing device (11) is input into PQW 256-micro positive pressure signal (4 mA-20 mA) input address (16) of the PLC module, and after being compared with the set pressure value by the industrial personal computer, the PIW 258-dust exhaust control valve signal (4 mA-20 mA) output address (17) is output to the dust exhaust automatic valve (14) to adjust the dust exhaust opening angle; the detection data and the pressure curve in the furnace can be displayed on an industrial personal computer.

Compared with the prior device, the utility model has the beneficial effects that:

in order to ensure the atmosphere in the furnace and compensate the gas loss exhausted by the exhaust valve all the time, the original equipment fills a large amount of argon gas before the arc striking to exhaust the air in the furnace, the flow rate of the argon gas is 200L/min, and the time of the argon gas filling is 30 min; argon gas with fixed flow is filled in the smelting process, and the gas atmosphere in the furnace is ensured according to different steel types and generally between 110L/min and 130L/min. After the utility model is used, argon gas is still filled at the flow rate of 200L/min before arc striking, the pressure value in the furnace is monitored in the process, when the micro-positive pressure requirement of 0.4bar-0.6bar is met, the system automatically adjusts the opening angle of the dust exhaust automatic valve, the dust exhaust valve is not completely closed, the function of discharging flue gas is still kept, meanwhile, the pressure in the furnace is also reduced, and the argon gas consumption is reduced.

Drawings

FIG. 1 is a schematic structural view of a furnace head part of a protective atmosphere electroslag furnace;

FIG. 2 is an enlarged schematic view of the atmosphere protection shield and tie rod seal;

FIG. 3 is an enlarged schematic view of the protective cover and the mold seal;

FIG. 4 is a schematic diagram of dust discharge control of a furnace head of a protective atmosphere electroslag furnace;

fig. 5 is an electrical control schematic diagram of the PLC module group.

Reference numerals: 1-pull rod sliding contact part, 2-atmosphere protective cover and pull rod sealing, 3-pull rod, 4-dust exhaust port, 5-conductive flange contact surface row, 6-atmosphere protective cover, 7-atmosphere protective cover and crystallizer sealing, 8-crystallizer, 9-electrode, 10-steel ingot, 11-pressure testing device, 12-furnace body, 13-dust exhaust manual valve (bypass valve), 14-dust exhaust automatic valve, 15-dust exhaust manual valve (main valve), 16-PQW 256-micro positive pressure signal (4 mA-20 mA) input address, and 17-PIW 258-dust exhaust control valve signal (4 mA-20 mA) output address.

Detailed Description

Sealing part: in the original electroslag furnace, the opening amount of a manual valve is too small, so that the pressure in the furnace is higher, in a high-temperature dusty environment, gas leakage is very easy at the positions of an atmosphere protective cover and a pull rod seal 2 and the positions of the atmosphere protective cover and a crystallizer seal 7, leaked gas and dust containing fluoride are accumulated between a pull rod 3 and a carbon brush to cause poor sliding contact and arcing discharge, and a large-current contact element is damaged; the oxygen content analyzer in the originally designed atmosphere protection cover 6 is very easy to block due to a high-temperature dusty environment, a sensor is easy to damage, the measurement value is often inaccurate, or data cannot be normally detected, and the atmosphere state in the furnace is unknown. As shown in fig. 1, firstly, to ensure the sealing performance of the furnace platform, the atmosphere protection cover and the pull rod seal 6 (shown in fig. 2), the atmosphere protection cover and the crystallizer seal 7 (shown in fig. 3) of the electroslag furnace are replaced and repaired, a flange is welded at the opening of the pressure testing device 11, and a proper seal is installed in a matching way, so as to ensure the sealing performance of the electroslag furnace.

Pressure test apparatus part:

the most important point of ensuring the proper protective atmosphere of the electroslag furnace is that the atmosphere at the upper part of the slag liquid surface is detected as far as possible at the detection point, but the protective gas atmosphere at the upper part of the molten pool is detected as far as possible, and the pressure testing device 11 is damaged due to the fact that the position is too low, the position is close to the slag surface and the temperature is too high, so that in order to consider the safe and stable use of the pressure testing device 11, a preliminary test is carried out by utilizing the electroslag furnace with a slag adding port on the original atmosphere protective cover 6, the position of the slag adding port and the atmosphere protective cover 6 form an angle of 45 degrees, the height is 250mm above the lower edge of the atmosphere protective cover 6, and the pressure testing device 11 can be normally used at the position; as the diameter of the slag adding opening is larger, the opening required by the pressure testing device 11 is not necessarily too large, and the problem of the service life of the pressure testing device 11 influenced by the temperature is also considered, as shown in figure 1, after the factors are comprehensively considered, a hole is formed at a proper position of the lower edge of the atmosphere protection cover 6 which is 300mm upwards, and the pressure testing device 11 is installed.

The control part:

the exhaust valve of the dust exhaust port 4 is provided with an opening amount which is adjusted according to different smelting stages and actual pressure conditions in the furnace. As shown in fig. 4, a dust discharging automatic valve 14 is added in front of an original main dust discharging manual valve 15 on the exhaust pipeline, and a dust discharging manual valve 13 is installed; the dust exhaust automatic valve 14 is an angle control valve, and the opening angle is adjustable; the dust-discharging manual valve 13 is connected with the dust-discharging automatic valve 14 in parallel and is used for ensuring that the dust-discharging manual valve 13 can be manually operated under the condition that the dust-discharging automatic valve 14 is not good; the gas pressure in the furnace reaches the set micro-positive pressure value of 0.4bar-0.6 bar.

As shown in fig. 5, the pressure signal detected by the pressure testing device 11 is inputted to the PQW 256-micro positive pressure signal (4 mA-20 mA) input address 16 of the PLC module by using the redundant I/0 port in the original PLC system, and after the PLC is compared with the set pressure value by the industrial personal computer, the pressure signal is outputted to the dust exhaust automatic valve 14 by the PIW 258-dust exhaust control valve signal (4 mA-20 mA) output address 17 to adjust the dust exhaust opening angle; the detection data and the pressure curve in the furnace can be displayed on an industrial personal computer.

The system is formally used, the sealing condition can be detected, the micro-positive pressure is not formed when the system is found, the maintenance treatment and sealing are arranged in time, the damage of various seals and protective covers is reduced, the condition that smoke leaks from the atmosphere protective cover 6 and the sealing parts of various interfaces due to overhigh pressure in the furnace cannot be seen at present, the arcing accident is avoided, the good atmosphere in the furnace is kept, and the smelting quality is ensured.

Claims (2)

1. The micro-positive pressure detection device for the protective atmosphere electroslag furnace is characterized in that the micro-positive pressure detection and control system consists of a sealing part, a pressure testing device part and a control part;

the sealing part is used for ensuring the sealing property of the furnace platform, replacing and repairing the atmosphere protection cover of the electroslag furnace and the sealing of the pull rod for two seconds, and sealing the atmosphere protection cover and the crystallizer for four-night; adding a pressure testing device in the lower position of the atmosphere protection cover, forming a hole, welding a flange, and installing a proper seal in a matched manner;

the pressure testing device part is used for forming a hole in a proper upward position of the atmosphere protection cover and installing a pressure testing device;

the control part and an exhaust valve of the dust exhaust port can adjust the opening amount according to different smelting stages and actual pressure conditions in the furnace, the dust exhaust automatic valve is additionally arranged on an exhaust pipeline before the original main dust exhaust manual valve self-operation, and the dust exhaust manual valve is installed with a selection mark; the dust exhaust automatic valve is the angle control valve in first-generation, and the opening angle is adjustable;

according to the method, a pressure signal detected by a pressure test device is input into an PQW 256-micro positive pressure signal input address of a PLC module through a redundant I/O port in an original PLC system, and is output to an automatic dust exhaust valve through a PIW 258-dust exhaust control valve signal output address ⒄ after the PLC module is compared with a set pressure value, and the dust exhaust opening angle is adjusted; the detection data and the pressure curve in the furnace can be displayed on an industrial personal computer.

2. The micro-positive pressure detection device for a protective atmosphere electroslag furnace according to claim 1,

the pressure testing device is located at a hole forming position on the atmosphere protection cover sixteenth, and is selected to be located 300mm above the lower edge of the atmosphere protection cover sixthly;

the dust-exhausting manual valve and the dust-exhausting automatic valve are coupled in parallel, and the dust-exhausting manual valve can be used for self-absorption instead of the dust-exhausting automatic valve, so that the gas pressure in the furnace reaches the set micro-positive pressure value of 0.4-0.6 bar.

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