Method for replacing an oil cylinder of an intermediate vessel of an electric furnace

Abstract

The application discloses a kind of replacement methods of intermediate tank lifting oil cylinder in electric furnace, the method includes the following steps: a. using the hydraulic system of intermediate tank lifting drive device to make lifting frame rise to the highest position, and lifting frame is supported and fixed;B. disassemble the bearing seat corresponding to the trunnion of the lifting oil cylinder to be replaced, make the cylinder barrel of the lifting oil cylinder to be replaced drop to the lowest position, the piston rod of the lifting oil cylinder to be replaced is ejected from the installation hole on bow beam;C. dismount the hydraulic pipe connected with the lifting oil cylinder to be replaced, the lifting oil cylinder to be replaced is then transposed, and then use the crane to lift the lifting oil cylinder to be replaced;D. install new lifting oil cylinder and carry out exhaust;E. the intermediate tank lifting drive device after replacing lifting oil cylinder is debugged.The application only disassembles the bearing seat of the trunnion on both sides of the lifting oil cylinder to be replaced, i.e. the replacement of lifting oil cylinder can be realized, greatly simplifies the operation process, reduces the labor intensity of maintenance personnel, and improves the replacement efficiency of lifting oil cylinder.

Description

Technical Field

[0001] This invention relates to a method for replacing the lifting cylinder of an electric furnace tundish, applicable to a clamp-type non-guided tundish lifting drive device for electric furnaces. This method can effectively improve the efficiency of replacing the lifting cylinder of the electric furnace tundish and belongs to the field of metallurgical technology. Background Technology

[0002] In the electric arc furnace (EAF) steelmaking process, molten steel that has passed the EAF smelting is first poured from the ladle into the tundish, and then from the tundish into the crystallizer, where it cools and solidifies to form a cast billet. According to the EAF steelmaking process specifications, to ensure stable and normal pouring from the tundish nozzle during the pouring of molten steel into the crystallizer, automatic adjustment of the tundish slag line is required. This process relies on a tundish lifting drive device.

[0003] like Figures 1-5 As shown, the electric furnace clamp-type guideless intermediate tank lifting drive device mainly consists of a traveling frame, two lifting cylinders, and a lifting frame 7. The two lifting cylinders are a floating side lifting cylinder 1 and a fixed side lifting cylinder 2. The traveling frame is assembled from two bow-shaped beams, a low-rail traveling beam 5, and an elevated traveling beam 6. The two bow-shaped beams are a floating side bow-shaped beam 3 and a fixed side bow-shaped beam 4. All bow-shaped beams, the low-rail traveling beam 5, and the elevated traveling beam 6 are welded from steel plates, with internal reinforced partitions and external reinforcing ribs to enhance the overall structural strength. The low-rail traveling beam 5 is mounted above the casting platform 17, and the elevated traveling beam 6 is mounted above the intermediate tank platform. The upper ends of the two bow-shaped beams are fixedly connected to both ends of the elevated traveling beam 6 via flanges, and the lower ends are fixedly connected to both ends of the low-rail traveling beam 5 via flanges. Vertical mounting holes 18 are provided on both bow-shaped beams for mounting the piston rods of the floating side lifting cylinder 1 and the fixed side lifting cylinder 2, respectively.

[0004] The lifting frame 7 adopts a H-shaped frame structure, with a pre-reserved notch on the side facing the crystallizer to allow for the installation of the intermediate tank stopper rod mechanism. Each end of the middle crossbeam of the lifting frame 7 has a set of bearing bases, with two bearing bases in each set. The two sets of bearing bases have different structures: the two bearing bases at one end of the middle crossbeam are floating side bearing bases 11, and the two bearing bases at the other end are fixed side bearing bases 12. The trunnions 15 on both sides of the two lifting cylinders are rotatably connected to the two sets of bearing bases via bearing seats. The trunnions 15 on both sides of the cylinder barrel of the floating side lifting cylinder 1 are rotatably connected to the two floating side bearing bases 11 via two floating side bearing seats 13. The trunnions 15 on both sides of the cylinder barrel of the fixed side lifting cylinder 2 are rotatably connected to the two fixed side bearing bases 12 via two fixed side bearing seats 14. The piston rods of the floating side lifting cylinder 1 and the fixed side lifting cylinder 2 face downwards and are inserted into the corresponding mounting holes 18 of the floating side bow beam 3 and the fixed side bow beam 4, respectively. When the equipment is running, the floating side lifting cylinder 1 and the fixed side lifting cylinder 2 extend and retract synchronously, driving the lifting frame 7 and the intermediate tank 19 mounted on it to lift and lower as a whole, thereby completing the automatic adjustment of the slag line. The upper part of the lifting frame 7 is also equipped with an intermediate tank guard plate 8, which protects the intermediate tank 19.

[0005] In the electric arc furnace steelmaking process, if the floating side lifting cylinder 1 or the fixed side lifting cylinder 2 experiences external or internal leakage, it must be replaced. The traditional replacement method involves first disassembling the lifting frame 7 connected to the floating side lifting cylinder 1 and the fixed side lifting cylinder 2, then replacing the faulty lifting cylinder, and finally reconnecting the lifting frame 7 to the two lifting cylinders. This method requires disassembling and assembling four bearing seats, making the operation very cumbersome and the debugging task heavy. It not only increases the workload of maintenance personnel but also reduces equipment maintenance efficiency. Therefore, it is necessary to improve this method. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for replacing the lifting cylinder of an electric furnace intermediate tank, thereby simplifying the operation process, reducing the labor intensity of maintenance personnel, and improving the replacement efficiency of the lifting cylinder.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for replacing the lifting cylinder of an electric furnace intermediate tank, the method comprising the following steps: a. Use the hydraulic system of the intermediate tank lifting drive device to raise the lifting frame to the highest position, and use the support device to support and fix the lifting frame; b. Remove the bearing seats corresponding to the trunnions on both sides of the lifting cylinder to be replaced, and use the hydraulic system of the intermediate tank lifting drive device to lower the cylinder of the lifting cylinder to be replaced to the lowest position, and push the piston rod of the lifting cylinder to be replaced out of the mounting hole on the bow beam. c. Disconnect the hydraulic pipe connected to the lifting cylinder to be replaced, rotate the lifting cylinder to be replaced so that the trunnions on both sides are parallel to the opening direction of the two sets of bearing bases on the lifting frame, and then use the overhead crane to lift the lifting cylinder to be replaced away. d. Install the new lifting cylinder and bleed the air. Install the piston rod of the new lifting cylinder into the mounting hole of the corresponding bow beam, rotate the new lifting cylinder so that the trunnions on both sides are perpendicular to the opening direction of the two sets of bearing bases, connect the new lifting cylinder to the hydraulic pipe of the hydraulic system, vent the new lifting cylinder, then raise the cylinder of the new lifting cylinder to the highest position and reinstall the bearing base. e. Debug the intermediate tank lifting drive device after replacing the lifting cylinder.

[0008] The above-mentioned method for replacing the lifting cylinder of the intermediate tank of the electric furnace includes two sets of support devices, which are respectively set at the lower ends of the lifting frame. Each set of support devices includes a hydraulic jack and a top bar. The top bar is placed vertically on the pouring platform, and the hydraulic jack is placed on top of the top bar. The top bar of the hydraulic jack rests on the lower surface of the lifting frame.

[0009] The method for replacing the lifting cylinder of the electric furnace intermediate tank described above involves venting the new lifting cylinder by using the hydraulic system of the intermediate tank lifting drive device to repeatedly raise and lower the cylinder barrel of the new lifting cylinder.

[0010] The replacement method for the lifting cylinder of the electric furnace intermediate tank described above involves using a hydraulic jack and a wooden block to push the piston rod of the lifting cylinder to be replaced out of the mounting hole on the bow beam. Specifically, the wooden block is placed on the pouring platform directly below the lifting cylinder to be replaced, and the hydraulic jack is placed on top of the wooden block. By operating the hydraulic jack, the piston rod of the lifting cylinder to be replaced is pushed out of the mounting hole on the bow beam using the jack's push rod.

[0011] The replacement method for the lifting cylinder of the electric furnace intermediate tank described above involves rotating the lifting cylinder 90 degrees around its axis.

[0012] This invention allows for the replacement of the lifting cylinder of the electric furnace intermediate tank by simply disassembling and assembling the bearing seats of the trunnions on both sides of the lifting cylinder to be replaced. The relevant components of the non-faulty lifting cylinder do not need to be disassembled and assembled. Compared with the traditional replacement method, this greatly simplifies the operation process, reduces the labor intensity of maintenance personnel, and improves the replacement efficiency of the lifting cylinder. Attached Figure Description

[0013] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1 This is a 3D view of an electric furnace clamp-type, guideless intermediate tank lifting drive device (the arrows in the figure indicate the pouring direction). Figure 2 This is the main view of the electric furnace clamp-type, guideless intermediate tank lifting drive device; Figure 3 This is a left view of an electric furnace clamp-type, guideless intermediate tank lifting drive device; Figure 4 This is a schematic diagram of the walking frame structure; Figure 5 This is a schematic diagram showing the connection between the lifting cylinder and the lifting frame; Figure 6 This is a schematic diagram showing the cylinders of the two lifting cylinders raised to their highest position. Figure 7 This is a schematic diagram of the moving-side lifting cylinder barrel descending to its lowest position; Figure 8 This is a schematic diagram showing the piston rod of the floating side lifting cylinder being pushed out; Figure 9 This is a schematic diagram of a hydraulic system.

[0015] The following are the labels in the diagram: 1. Floating side lifting cylinder; 2. Fixed side lifting cylinder; 3. Floating side bow beam; 4. Fixed side bow beam; 5. Low-rail traveling beam; 6. Elevated traveling beam; 7. Lifting frame; 8. Intermediate tank guard plate; 9. Hydraulic jack; 10. Top bar; 11. Floating side bearing base; 12. Fixed side bearing base; 13. Floating side bearing seat; 14. Fixed side bearing seat; 15. Trunnion; 16. Wooden block; 17. Pouring platform; 18. Mounting hole, 19. Intermediate tank, 20. No. 1 high-pressure ball valve, 21. No. 3 high-pressure ball valve, 22. No. 1 bridge speed control circuit, 23. No. 3 hydraulic control check valve, 24. No. 2 relief valve, 25. No. 2 hydraulic control check valve, 26. No. 2 high-pressure ball valve, 27. No. 4 high-pressure ball valve, 28. No. 2 bridge speed control circuit, 29. No. 4 hydraulic control check valve, 30. Electro-hydraulic directional valve, 31. Two-position four-way directional valve, 32. No. 1 relief valve, 33. No. 1 hydraulic control check valve. Detailed Implementation

[0016] This invention addresses the shortcomings of existing technologies by providing a method for replacing the lifting cylinder of an electric furnace tundish. The method first fixes the lifting frame 7 at a high position. Then, utilizing the detachable and separate structure of the lifting cylinder (i.e., the floating side lifting cylinder 1 or the fixed side lifting cylinder 2) and the bearing seat (i.e., the floating side bearing seat 13 or the fixed side bearing seat 14), and the ability to be lifted out from between the two bearing bases (the floating side bearing base 11 or the fixed side bearing base 12) of the lifting frame 7 after turning, the electric furnace tundish lifting cylinder can be quickly replaced. This improves the safety and reliability of the electric furnace tundish lifting cylinder replacement, saves maintenance time and costs, and increases production efficiency.

[0017] This method includes the following steps: a. The hydraulic system of the intermediate tank lifting drive device is used to raise the lifting frame 7 to the highest position, and the lifting frame 7 is supported and fixed by the support device. Two sets of support devices are set up and respectively set at the lower part of both ends of the lifting frame 7. Each set of support devices includes a hydraulic jack 9 and a top bar 10. The top bar 10 is placed vertically on the pouring platform 17, and the hydraulic jack 9 is placed on the top of the top bar 10. The top bar of the hydraulic jack 9 rests on the lower surface of the lifting frame 7. b. Remove the bearing seats corresponding to the trunnions 15 on both sides of the lifting cylinder to be replaced, and use the hydraulic system of the intermediate tank lifting drive device to lower the cylinder of the lifting cylinder to be replaced to the lowest position, and push the piston rod of the lifting cylinder to be replaced out of the mounting hole on the bow beam. c. Disconnect the hydraulic pipe connected to the lifting cylinder to be replaced, rotate the lifting cylinder to be replaced so that the trunnions on both sides are parallel to the opening direction of the two sets of bearing bases on the lifting frame, and then use the overhead crane to lift the lifting cylinder to be replaced away. d. Install the new lifting cylinder and bleed the air. Install the piston rod of the new lifting cylinder into the mounting hole 18 of the corresponding bow beam, then rotate the new lifting cylinder (rotate 90 degrees around its axis) so that the trunnions 15 on both sides are perpendicular to the opening direction of the two sets of bearing bases. Connect the new lifting cylinder to the hydraulic pipe of the hydraulic system, and use the hydraulic system to make the cylinder of the new lifting cylinder rise and fall repeatedly to exhaust the air from the new lifting cylinder. Then raise the cylinder of the new lifting cylinder to the highest position and reinstall the bearing base. e. Debug the intermediate tank lifting drive device after replacing the lifting cylinder.

[0018] The replacement of the lifting cylinder in the lifting drive device of the electric furnace clamp-type non-guided intermediate tank will be used as an example for explanation.

[0019] See Figure 9The hydraulic system of the electric furnace clamp-type non-guided intermediate tank lifting drive device includes a floating side lifting cylinder 1, a fixed side lifting cylinder 2, a two-position four-way directional valve 31, a first relief valve 32, a first hydraulically controlled check valve 33, a first high-pressure ball valve 20, a third high-pressure ball valve 21, a bridge-type speed control circuit 22, a third hydraulically controlled check valve 23, a second relief valve 24, a second hydraulically controlled check valve 25, a second high-pressure ball valve 26, and a fourth high-pressure ball valve. 27. Bridge-type speed control circuit; 28. No. 4 hydraulic control check valve; 29. ​​Electro-hydraulic directional valve; 30. The P port of the electro-hydraulic directional valve 30 and the two-position four-way directional valve 31 are connected to the high-pressure oil pipe, and the T port is connected to the oil tank; the A port of the two-position four-way directional valve 31 is blocked; one end of the No. 1 high-pressure ball valve 20 is connected to the B port of the two-position four-way directional valve 31, and the other end is connected to the rod chamber of the floating side lifting cylinder 1 and the control oil port of the No. 1 hydraulic control check valve 33 through the oil pipe. Connect; one end of the second high-pressure ball valve 26 is connected to port B of the two-position four-way directional valve 31, and the other end is connected via an oil pipe to the rod chamber of the fixed-side lifting cylinder 2 and the control oil port of the second hydraulic control check valve 25; port A of the electro-hydraulic directional valve 30 is connected sequentially via the third hydraulic control check valve 23, the bridge speed control circuit 22, the third high-pressure ball valve 21, and the first hydraulic control check valve 33 to the rodless chamber of the floating-side lifting cylinder 1; the electro-hydraulic directional valve 30... Port A is also connected in sequence to the rodless chamber of the fixed-side lifting cylinder 2 via hydraulic control check valve 29, bridge speed control circuit 28, high-pressure ball valve 27, and hydraulic control check valve 25. The control ports of hydraulic control check valve 23 and hydraulic control check valve 29 are connected to port B of electro-hydraulic directional valve 30. Overflow valve 32 and overflow valve 24 are connected to the rodless chambers of the floating-side lifting cylinder 1 and the fixed-side lifting cylinder 2, respectively.

[0020] The method will now be explained in detail by taking the replacement of the floating side lifting cylinder 1 as an example (the replacement of the fixed side lifting cylinder 2 is the same).

[0021] Step 1: Preparation The hydraulic system of the intermediate tank lifting drive device is used to raise the lifting frame 7 to its highest position, and the supporting device is used to support and fix the lifting frame 7. When solenoid 1DT of the two-position four-way directional valve 31 is energized, solenoid 2DT of the electro-hydraulic directional valve 30 is de-energized and solenoid 3DT is energized. The pressure in the hydraulic line is transmitted through the two-position four-way directional valve 31, high-pressure ball valve 20, and high-pressure ball valve 26 to the rod chambers of the floating side lifting cylinder 1 and the fixed side lifting cylinder 2, respectively. At the same time, hydraulic control check valves 33 and 25 are opened. The pressure in the hydraulic line is transmitted through the electro-hydraulic directional valve 30, hydraulic control check valve 23, bridge speed control circuit 22, high-pressure ball valve 21, and hydraulic control check valve 33 to the rodless chamber of the floating side lifting cylinder 1, and through the electro-hydraulic directional valve 30, hydraulic control check valve 29, bridge speed control circuit 28, high-pressure ball valve 27, and hydraulic control check valve 25 to the rodless chamber of the fixed side lifting cylinder 2. The cross-sectional area of ​​the oil in the rodless chamber of the fixed-side lifting cylinder 2 is larger than that in the rod chamber. The cylinders of the floating-side lifting cylinder 1 and the fixed-side lifting cylinder 2 move upward. High-pressure oil from the hydraulic line enters the rodless chamber of the floating-side lifting cylinder 1 through the electro-hydraulic directional valve 30, the No. 3 hydraulic control check valve 23, the bridge speed control circuit 22, the No. 3 high-pressure ball valve 21, and the No. 1 hydraulic control check valve 33, and then enters the rodless chamber of the fixed-side lifting cylinder 2 through the electro-hydraulic directional valve 30, the No. 4 hydraulic control check valve 29, the bridge speed control circuit 28, the No. 4 high-pressure ball valve 27, and the No. 2 hydraulic control check valve 25. The high-pressure oil in the rod chamber of the floating-side lifting cylinder 1 returns to the hydraulic line through the No. 1 high-pressure ball valve 20 and the two-position four-way directional valve 31. The high-pressure oil in the rod chamber of the fixed-side lifting cylinder 2 returns to the hydraulic line through the No. 2 high-pressure ball valve 26 and the two-position four-way directional valve 31.

[0022] When the cylinders of the floating side lifting cylinder 1 and the fixed side lifting cylinder 2 move upward, they drive the floating side bearing seat 13, the fixed side bearing seat 14, and the lifting frame 7 to rise synchronously. When the lifting frame 7 reaches the highest position, the second high-pressure ball valve 26 and the fourth high-pressure ball valve 27 are closed. The lower parts of both ends of the lifting frame 7 are supported and fixed by hydraulic jacks 9 and jacks 10, respectively.

[0023] Step 2: Disassembly Disassemble the two floating side bearing seats 13 between the trunnions 15 on both sides of the floating side lifting cylinder 1 and the two floating side bearing bases 11 on the lifting frame 7, remove the components that make up the two floating side bearing seats 13, and use the hydraulic system of the intermediate tank lifting drive device to lower the cylinder of the floating side lifting cylinder 1 to the lowest position, and push the piston rod of the floating side lifting cylinder 1 out of the mounting hole 18 on the floating side bow beam 3: After disassembling the floating side bearing housing 13, the solenoid 1DT of the two-position four-way directional valve 31 is energized, and at the same time, the solenoid 2DT of the electro-hydraulic directional valve 30 is energized, while the solenoid 3DT is de-energized. High-pressure oil from the hydraulic pipeline enters the rod chamber of the floating side lifting cylinder 1 through the two-position four-way directional valve 31 and the first high-pressure ball valve 20, pushing the cylinder barrel and trunnion 15 of the floating side lifting cylinder 1 to descend, and at the same time opening the first hydraulic control check valve 33. High-pressure oil from the hydraulic pipeline opens the third hydraulic control check valve 23 and the fourth hydraulic control check valve 29 through the electro-hydraulic directional valve 30. The hydraulic oil in the rodless chamber of the floating side lifting cylinder 1 flows back to the oil tank through the first hydraulic control check valve 33, the third high-pressure ball valve 21, the bridge speed control circuit 22, the third hydraulic control check valve 23, the electro-hydraulic directional valve 30, and the return oil pipeline. The cylinder barrel of the floating side lifting cylinder 1 descends. When the cylinder of the floating side lifting cylinder 1 descends to its lowest position, another hydraulic jack 9 and a wooden block 16 are used to push the piston rod of the floating side lifting cylinder 1 out of the mounting hole 18 of the floating side bow beam 3. The specific operation method is as follows: place the wooden block 16 on the pouring platform 17 directly below the piston rod of the floating side lifting cylinder 1, place the hydraulic jack 9 on the upper part of the wooden block 16, and operate the hydraulic jack 9 to push the piston rod of the floating side lifting cylinder 1 out of the mounting hole on the bow beam using the push rod of the hydraulic jack 9.

[0024] Step 3: Turn and lift out Disconnect the hydraulic pipe connected to the floating side lifting cylinder 1, rotate the floating side lifting cylinder 1 (rotate 90 degrees around its axis) so that the trunnion of the floating side lifting cylinder 1 is parallel to the opening direction of the floating side bearing base 11 of the lifting frame 7, and then use the overhead crane inside the workshop to lift the floating side lifting cylinder 1 away. Step 4: Installation and venting of the new lifting cylinder After the new mobile side lifting cylinder 1 is hoisted into place, its piston rod is installed into the mounting hole 18 of the mobile side bow beam 3. The new mobile side lifting cylinder 1 is rotated so that its trunnion is perpendicular to the opening direction of the mobile side bearing base 11 of the lifting frame 7. The new mobile side lifting cylinder 1 is connected to the hydraulic pipe of the hydraulic system. The cylinder of the mobile side lifting cylinder 1 is repeatedly raised and lowered using the hydraulic system to vent the air from the mobile side lifting cylinder 1. Then, the cylinder of the mobile side lifting cylinder 1 is raised to the highest position and the mobile side bearing base 13 is reinstalled. After the new mobile side lifting cylinder 1 rotates, the solenoid 1DT of the two-position four-way directional valve 31 is energized, while the solenoid 2DT of the electro-hydraulic directional valve 30 is de-energized and the solenoid 3DT is energized. The pressure of the hydraulic pipeline is transmitted to the rod chamber of the mobile side lifting cylinder 1 through the two-position four-way directional valve 31 and the first high-pressure ball valve 20, and at the same time, the first hydraulic control check valve 33 is opened. The pressure of the hydraulic pipeline is transmitted to the rodless chamber of the mobile side lifting cylinder 1 through the electro-hydraulic directional valve 30, the third hydraulic control check valve 23, the bridge speed control circuit 22, the third high-pressure ball valve 21, and the first hydraulic control check valve 33. Since the cross-sectional area of ​​the oil in the rodless chamber of the mobile side lifting cylinder 1 is larger than that in the rod chamber, the cylinder of the mobile side lifting cylinder 1 rises.

[0025] When the cylinder barrel and trunnion 15 of the new moving side lifting cylinder 1 rise to the highest position, the solenoid 1DT of the two-position four-way directional valve 31 is energized, and at the same time, the solenoid 2DT of the electro-hydraulic directional valve 30 is energized and the solenoid 3DT is de-energized. The high-pressure oil from the hydraulic pipeline passes through the two-position four-way directional valve 31 and the first high-pressure ball valve 20 to open the first hydraulic control check valve 33, and enters the rod chamber of the new moving side lifting cylinder 1, pushing the cylinder barrel and trunnion 15 of the new moving side lifting cylinder 1 to descend. The hydraulic oil in the rodless chamber of the new moving side lifting cylinder 1 flows back to the oil tank through the first hydraulic control check valve 33, the third high-pressure ball valve 21, the bridge speed control circuit 22, the third hydraulic control check valve 23, the electro-hydraulic directional valve 30 and the return oil pipeline.

[0026] After the cylinder barrel and trunnion 15 of the new mobile side lifting cylinder 1 descend to the lowest position, the hydraulic system is used to raise the cylinder barrel of the mobile side lifting cylinder 1 to the highest position. This cycle is repeated many times to purge the air inside the new mobile side lifting cylinder 1. Then, the cylinder barrel and trunnion 15 of the new mobile side lifting cylinder 1 are raised to the highest position, and the two sets of mobile side bearing seats 13 are reinstalled so that the cylinder barrel of the new mobile side lifting cylinder 1 is hinged to the lifting frame 7.

[0027] Step 5: Debug the intermediate tank lifting drive device after replacing the lifting cylinder. Open high-pressure ball valve 26 (No. 2) and high-pressure ball valve 27 (No. 4), remove hydraulic jacks 9 and jacks 10 from both sides of the lifting frame 7, and then perform adjustments: Improve framework 7 down When the solenoid 1DT of the two-position four-way directional valve 31 is energized, the solenoid 2DT of the electro-hydraulic directional valve 30 is simultaneously energized, and the solenoid 3DT is de-energized. High-pressure oil from the hydraulic line enters the rod chambers of the floating-side lifting cylinder 1 and the fixed-side lifting cylinder 2 through the two-position four-way directional valve 31, the first high-pressure ball valve 20, and the second high-pressure ball valve 26, respectively. This pushes the cylinders of the floating-side lifting cylinder 1 and the fixed-side lifting cylinder 2, causing the floating-side bearing seat 13, the fixed-side bearing seat 14, and the lifting frame 7 to descend. Simultaneously, the first hydraulic control check valve 33 and the second hydraulic control check valve 25 are opened. High-pressure oil from the pressure pipeline opens hydraulic check valves 23 and 29 via electro-hydraulic directional valve 30. Hydraulic oil in the rodless chamber of the floating lifting cylinder 1 flows back to the oil tank sequentially through hydraulic check valve 33, high-pressure ball valve 21, bridge speed control circuit 22, hydraulic check valve 23, electro-hydraulic directional valve 30, and the return oil pipeline. Hydraulic oil in the rodless chamber of the fixed lifting cylinder 2 flows back to the oil tank sequentially through hydraulic check valve 25, high-pressure ball valve 27, bridge speed control circuit 28, hydraulic check valve 29, electro-hydraulic directional valve 30, and the return oil pipeline. The lifting frame 7 stops descending to its lowest position.

[0028] Improve the framework 7 When the solenoid 1DT of the two-position four-way directional valve 31 is energized, the solenoid 2DT of the electro-hydraulic directional valve 30 is de-energized and the solenoid 3DT is energized. The cylinders of the floating side lifting cylinder 1 and the fixed side lifting cylinder 2 move upward, driving the floating side bearing seat 13, the fixed side bearing seat 14, and the lifting frame 7 to rise. The lifting frame 7 stops when it reaches the highest position.

[0029] During the lifting frame 7's ascent or descent, the speeds of the new floating side lifting cylinder 1 and the fixed side lifting cylinder 2 are synchronized by fine-tuning the No. 1 bridge speed control circuit 22 or the No. 2 bridge speed control circuit 28.

[0030] After debugging, it will be delivered to the production operation staff for use.

[0031] This invention achieves cylinder replacement by using a fixed lifting frame and the hydraulic system of the intermediate tank lifting drive device to independently control the cylinder lifting of the lifting cylinder. The related components of the other lifting cylinder do not need to be disassembled, thereby simplifying the operation, reducing the workload of maintenance, and improving maintenance efficiency.

Claims

1. A method for replacing the lifting cylinder of an electric furnace intermediate tank, characterized in that, The method includes the following steps: a. The hydraulic system of the intermediate tank lifting drive device is used to raise the lifting frame (7) to the highest position, and the lifting frame (7) is supported and fixed by the support device; b. Remove the bearing seats corresponding to the trunnions (15) on both sides of the lifting cylinder to be replaced, and use the hydraulic system of the intermediate tank lifting drive device to lower the cylinder of the lifting cylinder to be replaced to the lowest position, and push the piston rod of the lifting cylinder to be replaced out of the mounting hole on the bow beam. c. Disconnect the hydraulic pipe connected to the lifting cylinder to be replaced, rotate the lifting cylinder to be replaced so that the trunnions on both sides are parallel to the opening direction of the two sets of bearing bases on the lifting frame, and then use the overhead crane to lift the lifting cylinder to be replaced away. d. Install the new lifting cylinder and bleed the air: Install the piston rod of the new lifting cylinder into the mounting hole (18) of the corresponding bow beam, rotate the new lifting cylinder so that the trunnions (15) on both sides are perpendicular to the opening direction of the two sets of bearing bases, connect the new lifting cylinder to the hydraulic pipe of the hydraulic system, vent the new lifting cylinder, and then raise the cylinder of the new lifting cylinder to the highest position and reinstall the bearing base. e. Debug the intermediate tank lifting drive device after replacing the lifting cylinder.

2. The method for replacing the lifting cylinder of an electric furnace intermediate tank according to claim 1, characterized in that, Two sets of support devices are provided, which are respectively set at the lower ends of the lifting frame (7). Each set of support devices includes a hydraulic jack (9) and a top bar (10). The top bar (10) is placed vertically on the pouring platform (17), and the hydraulic jack (9) is placed on top of the top bar (10). The top rod of the hydraulic jack (9) rests on the lower surface of the lifting frame (7).

3. A method for replacing the lifting cylinder of an electric furnace intermediate tank according to claim 1 or 2, characterized in that, The specific method for venting the new lifting cylinder is to use the hydraulic system of the intermediate tank lifting drive device to repeatedly raise and lower the cylinder barrel of the new lifting cylinder.

4. The method for replacing the lifting cylinder of an electric furnace intermediate tank according to claim 3, characterized in that, The piston rod of the lifting cylinder to be replaced is pushed out from the mounting hole on the bow beam by a hydraulic jack (9) and a wooden block (16). The specific method is as follows: place the wooden block (16) on the pouring platform (17) directly below the lifting cylinder to be replaced, place the hydraulic jack (9) on the top of the wooden block (16), and push the piston rod of the lifting cylinder to be replaced out from the mounting hole on the bow beam by operating the hydraulic jack (9).

5. The method for replacing the lifting cylinder of an electric furnace intermediate tank according to claim 4, characterized in that, The method for rotating the lifting cylinder is to rotate it 90 degrees around its axis.

Images