Control system for 3t intermediate frequency furnace

Abstract

The utility model provides a control system for a 3t intermediate frequency furnace, which belongs to the technical field of intermediate frequency furnace control, solves the problem that the production is influenced by shutdown caused by'frozen furnace 'repair of the original intermediate frequency furnace, and comprises a plurality of groups of intermediate frequency power supply cabinets, a capacitor cabinet, a furnace change switch and an intermediate frequency furnace, the medium-frequency power supply cabinets, the capacitor cabinets, the furnace change switches and the medium-frequency furnaces are sequentially connected, the medium-frequency power supply change-over switches are connected between output ends of two adjacent medium-frequency power supply cabinets, and at least one standby medium-frequency furnace is connected between two adjacent furnace change-over switches. According to the utility model, any intermediate-frequency power supply cabinet controls any intermediate-frequency furnace, and any plurality of intermediate-frequency furnaces can perform online production at the same time, so that the phenomenon of furnace freezing is avoided to the greatest extent, the normal operation is ensured, the production is not influenced, various production costs are saved, and the production efficiency is improved. And meanwhile, the safety performance of an existing intermediate frequency furnace system is greatly improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of medium frequency furnace control, and in particular relates to a control system for a 3t medium frequency furnace. Background Art

[0002] During the smelting and heating process of the 3T medium frequency furnace, when the steel in the furnace is completely melted but has not yet reached the furnace discharge temperature (the molten steel discharge temperature is 1650℃-1680℃), the medium frequency power supply cabinet will fail and the molten steel will solidify in the furnace. If the medium frequency power supply cannot be repaired within the specified time, a serious "frozen furnace" phenomenon will occur, and the longer the furnace is shut down, the more serious the "frozen furnace" phenomenon will be.

[0003] Even after the medium frequency power supply is repaired, it is still extremely dangerous to reopen the "frozen furnace" for smelting. In the on-site production process, in order to ensure safety, the furnace is often planed and rebuilt. This method requires the medium frequency power supply cabinet and the medium frequency furnace to be shut down for 72 hours, and the solidified molten steel temperature drops to about 300°C before it can be carried out. Originally, one medium frequency power supply cabinet controls one medium frequency furnace. Therefore, the repair will cause idle labor losses and increased maintenance costs. For example, an aluminum plant that was unable to complete order tasks on time due to idle labor will lose about 80,000 yuan in 5 days. Each furnace repair requires 3 people to work for two days, and the labor cost increases by 3,000 yuan. 2.2 tons of furnace building materials worth 18,920 yuan are required, and various costs total 101,920 yuan. Utility Model Content

[0004] The utility model aims to provide a control system for a 3t medium frequency furnace, so as to solve the problem that the original medium frequency furnace "frozen furnace" causes shutdown and affects production during repair.

[0005] The technical solution of the utility model is: a control system for a 3t medium frequency furnace, comprising a plurality of groups of medium frequency power supply cabinets, capacitor cabinets, furnace changer switches and medium frequency furnaces, the medium frequency power supply cabinets, capacitor cabinets, furnace changer switches and medium frequency furnaces being connected in sequence, and also comprising a medium frequency power supply conversion switch, the medium frequency power supply conversion switch being connected between the output ends of two adjacent medium frequency power supply cabinets, and at least one spare medium frequency furnace being connected between two adjacent furnace changer switches.

[0006] As a further improvement of the utility model, the medium frequency power supply cabinet and the capacitor cabinet are connected with a short-circuit busbar and a conductive busbar; two adjacent furnace changer switches are connected with a conductive busbar, and the furnace changer switch and the medium frequency furnace are connected with a flexible water-cooled cable.

[0007] As a further improvement of the present invention, the short-circuit busbar is made of high-strength alloy steel or heat-treated steel, and the conductive busbar is a conductive copper busbar.

[0008] The beneficial effects of the utility model are as follows: by adding an intermediate frequency power conversion switch between two adjacent intermediate frequency power supply cabinets, and adding a furnace changing switch between the capacitor cabinet and the intermediate frequency furnace, a plurality of spare intermediate frequency furnaces are connected in parallel between the two adjacent furnace changing switches, so that any intermediate frequency power supply cabinet can control any intermediate frequency furnace, and any plurality of intermediate frequency furnaces can be produced online at the same time, thereby solving the problem that two intermediate frequency furnaces cannot share the intermediate frequency power supply cabinet, and by switching the working mode of the intermediate frequency power supply cabinet and the intermediate frequency furnace respectively, the occurrence of the "frozen furnace" phenomenon is avoided to the greatest extent, and even if one of the intermediate frequency power supply cabinets or the intermediate frequency furnace fails, normal operation can be guaranteed without affecting production, thereby saving various production costs, and greatly improving the safety performance of the existing intermediate frequency furnace system.

[0009] The utility model has simple principle and strong operability; low transformation cost, high safety performance, small investment and quick effect; strong operability and strong replicability in the same industry application, and has an excellent promotion effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic diagram of the connection of the utility model system.

[0011] In the figure: 1- medium frequency power supply cabinet; 2- medium frequency power supply conversion switch; 3- capacitor cabinet; 4- furnace changeover switch; 5- medium frequency furnace; 6- short-circuit busbar; 7- conductive busbar; 8- flexible water-cooling cable; 9- spare medium frequency furnace. DETAILED DESCRIPTION

[0012] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0013] like Figure 1 As shown, a control system for a 3t medium frequency furnace includes multiple groups of medium frequency power supply cabinets 1, capacitor cabinets 3, furnace changer switches 4 and medium frequency furnaces 5, which are connected in sequence. The medium frequency power supply cabinets 1, capacitor cabinets 3, furnace changer switches 4 and medium frequency furnaces 5 also include a medium frequency power supply conversion switch 2, which is connected between the output ends of two adjacent medium frequency power supply cabinets 1, and at least one spare medium frequency furnace 9 is also connected between two adjacent furnace changer switches 4.

[0014] The medium frequency power supply cabinet 1 and the capacitor cabinet 3 are connected by a short-circuit busbar 6 and a conductive busbar 7; two adjacent furnace changer switches 4 are connected by a conductive busbar 7, and the furnace changer switch 4 and the medium frequency furnace 5 are connected by a flexible water-cooled cable 8.

[0015] The short-circuit busbar 6 is made of high-strength alloy steel or heat-treated steel, and the conductive busbar 7 is a conductive copper busbar.

[0016] The method of using the utility model comprises the following steps:

[0017] A: When the intermediate frequency power supply cabinet 1 is in normal state, set the intermediate frequency power supply conversion switch 2 to zero position, and then connect the furnace change switch 4 to the intermediate frequency furnace 5 to meet the demand for online production of the intermediate frequency furnace 5;

[0018] B: When one of the medium frequency power supply cabinets 1 has a fault that cannot be repaired in time, immediately remove the short-circuit busbar 6 of the faulty medium frequency power supply cabinet 1 to prevent the fault from expanding due to reverse power transmission; then place the medium frequency power supply conversion switch 2 in the position of the adjacent medium frequency power supply cabinet 1, connect the capacitor cabinet 3 of the faulty group with the adjacent medium frequency power supply cabinet 1, and supply power to the medium frequency furnace 5 of the faulty group through the adjacent medium frequency power supply cabinet 1 to enable normal operation;

[0019] C: When one of the intermediate frequency furnaces 5 fails, the furnace changing switch 4 in the faulty group is connected to the spare intermediate frequency furnace 9 to ensure the normal operation of the intermediate frequency furnace 5.

[0020] The capacitor cabinet 3 can improve the quality of electricity use and save electric energy, thereby improving the utilization rate of equipment, reducing line losses, improving the quality of electric energy, and making the power supply more stable and efficient; mechanical interlocking and electrical interlocking are set between adjacent furnace change switches 4, which can effectively prevent two medium frequency power supply cabinets 1 from supplying power to a medium frequency furnace 5 at the same time, causing a short circuit fault.

[0021] The conductive busbar 7 between the medium frequency power supply cabinet 1 and the capacitor cabinet 3 is designed as a three-section structure, which is convenient for quick disassembly. The faulty medium frequency power supply cabinet 1 can be effectively isolated in a short time, which is more convenient for disassembly and assembly than the original integral structure. The conductive busbar 7 is made of copper, which has excellent conductive properties and a conductivity much higher than other conductive materials. It is not easy to generate electric sparks during the conductive process of the conductive busbar 7, thus avoiding the occurrence of fire. At the same time, the conductive copper busbar has strong mechanical properties, good corrosion resistance, and is easy to process and shape.

[0022] The short-circuit busbar 6 is made of high-strength alloy steel or heat-treated steel, which has good strength and ductility, can meet the load requirements of the busbar clamping bolts, and has low corrosion and hydrogen embrittlement, can effectively avoid bolt deformation and breakage, thereby improving the reliability of the entire system.

[0023] The flexible water-cooled cable 8 can take away the heat inside the cable, thereby reducing the temperature of the cable, improving the safety and service life of the cable, and has the advantages of high safety, high reliability, energy saving and environmental protection, and easy installation.

[0024] Embodiment 1,

[0025] Take the example of setting three intermediate frequency power supply cabinets 1, three intermediate frequency furnaces 5 and two spare intermediate frequency furnaces 9 as an example. Figure 1As shown, when the three intermediate frequency power supply cabinets 1 are in normal state, the intermediate frequency power supply conversion switch 2 is in zero position, the two intermediate frequency power supply conversion switches 2 are disconnected from the three intermediate frequency power supply cabinets 1, the leftmost furnace changing switch 4 is placed in the position of the leftmost intermediate frequency furnace 5, the middle furnace changing switch 4 is placed in the position of the middle intermediate frequency furnace 5, and the rightmost furnace changing switch 4 is placed in the position of the rightmost intermediate frequency furnace 5. At this time, the three intermediate frequency furnaces 5 in the system are working normally.

[0026] If the leftmost intermediate frequency power supply cabinet 1 fails, it is only necessary to remove the short-circuit busbar 6 between the leftmost intermediate frequency power supply cabinet 1 and the leftmost capacitor cabinet 3, and at the same time place the leftmost intermediate frequency power supply conversion switch 2 in a position connected to the middle intermediate frequency power supply cabinet 1, so that the middle intermediate frequency power supply cabinet 1 can supply power to the leftmost intermediate frequency furnace 5, avoiding the occurrence of the "frozen furnace phenomenon" of the leftmost intermediate frequency furnace 5.

[0027] Similarly, if the middle intermediate frequency power supply cabinet 1 fails, it is only necessary to remove the short-circuit busbar 6 between the middle intermediate frequency power supply cabinet 1 and the middle capacitor cabinet 3, and at the same time place the leftmost or rightmost intermediate frequency power supply conversion switch 2 in a position connected to the left or right intermediate frequency power supply cabinet 1, so that the leftmost or rightmost intermediate frequency power supply cabinet 1 can supply power to the middle intermediate frequency furnace 5, thereby avoiding the occurrence of the "frozen furnace phenomenon" of the middle intermediate frequency furnace 5.

[0028] Similarly, if the intermediate frequency power supply cabinet 1 on the far right fails, it is only necessary to remove the short-circuit busbar 6 between the intermediate frequency power supply cabinet 1 on the far right and the capacitor cabinet 3 on the far right, and at the same time place the intermediate frequency power supply conversion switch 2 on the far right in a position connected to the intermediate frequency power supply cabinet 1 on the left, so that the intermediate frequency power supply cabinet 1 in the middle can supply power to the intermediate frequency furnace 5 on the far right, thereby avoiding the occurrence of the "frozen furnace phenomenon" of the intermediate frequency furnace 5 on the far right.

[0029] When one of the intermediate frequency furnaces 5 fails and the standby intermediate frequency furnace 9 needs to be switched to work, the leftmost furnace change switch 4 is placed on the standby intermediate frequency furnace 9 on the left, or the rightmost furnace change switch 4 is placed on the standby intermediate frequency furnace 9 on the right, so that the online production of the intermediate frequency furnace 5 and the standby intermediate frequency furnace 9 can be achieved. Special attention should be paid to the mechanical interlock and electrical interlock between adjacent furnace change switches 4 to prevent two intermediate frequency power supply cabinets 1 from simultaneously supplying power to one intermediate frequency furnace 5, resulting in a short circuit fault.

Claims

1. A control system for a 3t medium frequency furnace, characterized in that: The invention comprises a plurality of groups of medium frequency power supply cabinets (1), capacitor cabinets (3), furnace change switches (4) and medium frequency furnaces (5), wherein the medium frequency power supply cabinets (1), capacitor cabinets (3), furnace change switches (4) and medium frequency furnaces (5) are connected in sequence, and further comprises a medium frequency power supply conversion switch (2), wherein the medium frequency power supply conversion switch (2) is connected between the output ends of two adjacent medium frequency power supply cabinets (1), and at least one spare medium frequency furnace (9) is also connected between two adjacent furnace change switches (4).

2. A control system for a 3t medium frequency furnace according to claim 1, characterized in that: The intermediate frequency power supply cabinet (1) and the capacitor cabinet (3) are connected by a short-circuit busbar (6) and a conductive busbar (7); two adjacent furnace change switches (4) are connected by a conductive busbar (7); and the furnace change switch (4) and the intermediate frequency furnace (5) are connected by a flexible water-cooling cable (8).

3. A control system for a 3t medium frequency furnace according to claim 2, characterized in that: The short-circuit busbar (6) is made of high-strength alloy steel or heat-treated steel, and the conductive busbar (7) is a conductive copper busbar.

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