Method for quick replacement of air heat exchanger under steel loading machine concrete platform

Abstract

This invention relates to the field of heat exchanger replacement technology, and more particularly to a method for quickly replacing an air heat exchanger under the concrete platform of a steel loading machine. The technical solution includes: laying out and positioning the concrete platform at the bottom of the steel loading machine based on the pre- and post-demolition civil engineering boundary lines; partially cutting away the area between the two lines to form a lifting hole surrounded by the cut concrete; fabricating a movable steel platform adapted to the size of the lifting hole; embedding the steel platform into the lifting hole; vertically lifting the steel platform out after removing the steel loading machine casing to expose the vertical lifting channel; disassembling the connecting elbow of the air heat exchanger; using an overhead crane to vertically lift the old air heat exchanger out through the vertical lifting channel; vertically lifting the new air heat exchanger to the installation position and reinstalling the connecting elbow; re-embedding the steel platform and reinstalling the casing. This invention achieves vertical lifting replacement of the air heat exchanger without dismantling related equipment, effectively shortening the downtime.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger replacement technology, and in particular to a method for rapid replacement of an air heat exchanger under a concrete platform of a steel loading machine. Background Technology

[0002] Hot rolling furnaces are the core energy-consuming equipment in the hot rolling process, accounting for 40%-63% of the total energy consumption. Air heat exchangers, as key waste heat recovery devices in the furnace, play a crucial role in recovering waste heat from high-temperature flue gas (600-1100℃) to preheat combustion air, significantly contributing to reduced fuel consumption, improved thermal efficiency, and stable production operation. However, air heat exchangers operate under harsh conditions of high temperature, alternating thermal stress, and flue gas corrosion, commonly experiencing problems such as decreased heat exchange efficiency, damaged tube walls, and deteriorated safety performance. This makes them unsuitable for meeting increasingly stringent energy-saving and environmental protection requirements and the demands of continuous production. Therefore, periodic replacement of heat exchangers has become an essential part of production line equipment maintenance.

[0003] In existing technology, the air heat exchanger is located directly below the concrete platform of the steel loading machine, and its replacement is carried out using a horizontal reverse transport method. This method first requires a complete shutdown, isolation, and safety replacement of the heating furnace and related media piping system. Then, the flange connections and main pipeline connections of related equipment such as gas heat exchangers and steam heat exchangers located around the air heat exchanger are removed sequentially. Next, the cast refractory material above the gas heat exchanger is broken and cleaned. Finally, the air heat exchanger to be replaced is lifted to a certain height using a chain hoist, and channel steel is laid at its bottom. It is then moved horizontally to the crane's lifting range using chain hoisting before hoisting. The entire installation process is the reverse of the disassembly steps.

[0004] However, in existing replacement methods, due to the dense arrangement of gas heat exchangers, steam heat exchangers, and various media pipelines around the air heat exchanger, the traditional horizontal transport method requires the prior removal of the aforementioned related equipment to make room for the removal of the air heat exchanger. This process is cumbersome and the connection between each operation is poor. In addition, the working space under the concrete platform of the steel loading machine is extremely narrow and the ambient temperature is high, which seriously restricts the maintenance efficiency. As a result, the downtime cycle for a single air heat exchanger replacement operation is generally as long as about 20 days. The resulting long-term production line shutdown has a significant impact on the company's production rhythm and economic benefits. Therefore, this application proposes a method for rapid replacement of air heat exchangers under the concrete platform of the steel loading machine. Summary of the Invention

[0005] The purpose of this invention is to address the problems in the prior art where the replacement of air heat exchangers involves cumbersome and complex procedures, numerous steps in the overall construction process, and high requirements for seamless connections. This invention proposes a method for the rapid replacement of air heat exchangers under the concrete platform of a steel loading machine.

[0006] The technical solution of the present invention: A method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine, the method comprising the following steps: S1. Based on the civil engineering boundary lines before and after demolition, the concrete platform at the bottom of the steel loading machine is laid out and positioned. The area between the civil engineering boundary lines before and after demolition is partially cut off to form a hoisting hole surrounded by the cut concrete. The hoisting hole extends to the top of the air heat exchanger. A movable steel platform adapted to the size of the hoisting hole is made. The movable steel platform is used to be embedded in the hoisting hole to form a daily walking passage and can be lifted away to form a vertical hoisting passage when the air heat exchanger is replaced. S2. The movable steel platform is embedded and installed in the hoisting hole; S3. Remove the outer casing of the steel loading machine and vertically lift the movable steel platform, which is embedded in the lifting hole, to expose the vertical lifting channel; S4. Disconnect the connecting elbow between the air heat exchanger and the main pipeline, release the external pipeline constraints of the air heat exchanger, and use an overhead crane to vertically lift the old air heat exchanger out as a whole through the vertical hoisting channel. S5. Using an overhead crane, the new air heat exchanger is vertically hoisted to the installation position through the vertical hoisting channel, and the connecting elbow is reinstalled. S6. Reinstall the movable steel platform into the lifting hole and reinstall the steel loading machine housing.

[0007] Optionally, the movable steel platform includes a frame body, supporting beams, cover plates, guardrails, and lifting lugs. The frame body and the supporting beams form a rigid skeleton. The cover plates are laid on top of the frame body, the guardrails are located on the outside of the frame body, and the lifting lugs are located on both sides of the frame body.

[0008] Optionally, the dimensions of the movable steel platform are the same as the dimensions of the hoisting hole, and the movable steel platform is embedded in the hoisting hole, with the top surface of the cover plate flush with the top surface of the surrounding uncut concrete platform.

[0009] Optionally, the frame body and the supporting crossbeam are formed by processing and welding H-beams, and the lifting lugs are welded to both sides of the frame body for connecting the overhead crane hook.

[0010] Optionally, the cover plate is a 6mm thick patterned steel plate, which is fully welded to the top of the frame body.

[0011] Optionally, in step S1, a concrete wire cutting machine is used to cut the area of ​​the concrete platform located between the pre-demolition civil engineering boundary line and the post-demolition civil engineering boundary line into sections, and the waste is removed.

[0012] Optionally, in step S4, before disassembling the connecting elbow, the fastening bolts of the connecting elbow between the air heat exchanger and the main pipeline are removed, and the disassembled connecting elbow is lifted out and placed in place.

[0013] Optionally, in step S4, after the connecting elbow is completely removed and there are no external pipeline constraints, the old air heat exchanger is vertically lifted out by the overhead crane through the lifting hole.

[0014] Optionally, in step S5, when reinstalling the connecting elbow, the flange sealing surface and gasket of the connecting elbow are inspected to confirm that there is no damage or misalignment.

[0015] Optionally, in step S6, after the movable steel platform is reinstalled into the hoisting hole, the energy medium is restored, a leak test is performed on all connection parts of the air heat exchanger, and the equipment is put into no-load test run.

[0016] Compared with the prior art, this application includes at least one of the following beneficial technical effects: This invention creates a lifting hole by partially cutting away the concrete platform at the bottom of the steel loading machine and configuring a movable steel platform of suitable size as a removable temporary sealing component. This allows the air heat exchanger to be vertically lifted in and out of its installation position directly by an overhead crane without the need to dismantle surrounding related equipment such as gas heat exchangers and steam heat exchangers. The equipment replacement downtime cycle is reduced from the traditional 20 days to less than 6 days, effectively reducing production line downtime losses.

[0017] Furthermore, by utilizing the dual-purpose configuration of the movable steel platform, it can be embedded in the hoisting hole during non-maintenance periods as a daily walking passage, and can be hoisted away as a whole during maintenance periods to form a vertical hoisting passage. This eliminates the high-risk and intensive operation links such as manual high-altitude refractory material removal, open flame cutting, and chain hoisting and horizontal movement in traditional methods, effectively reducing the safety risks of operation in confined spaces and high-temperature environments.

[0018] Finally, the movable steel platform and the concrete cutting opening are fitted together with the same size, and the top surface of the cover plate is flush with the top surface of the surrounding concrete platform, which ensures the flatness of the passage and the safety of passage during daily operation of the equipment. The frame body and the supporting beam are welded with H-beams, and the cover plate is fully welded with patterned steel plates, which has high structural rigidity and strong load-bearing capacity, and can meet the various load-bearing requirements of steel loading machines and personnel walking. It is suitable for the replacement of air heat exchangers under the concrete platform of similar steel loading machines and can be promoted and applied in the field of metallurgical maintenance. Attached Figure Description

[0019] Figure 1 A schematic diagram of the overall structure of a method for quickly replacing an air heat exchanger under a concrete platform of a steel loading machine; Figure 2 A plan view of a movable steel platform for a method of quickly replacing the air heat exchanger under the concrete platform of a steel loading machine. Figure 3 A schematic diagram of a movable steel platform structure for a method of quickly replacing the air heat exchanger under the concrete platform of a steel loading machine. Figure 4 A schematic diagram of the equipment after concrete removal, illustrating a method for quickly replacing an air heat exchanger under the concrete platform of a steel loading machine. Figure 5 This is a flowchart of a method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine.

[0020] Attached reference numerals: 1. Frame body; 2. Supporting beam; 3. Cover plate; 4. Guardrail; 5. Lifting lug; 6. Concrete after cutting; 7. Air heat exchanger; 8. Lifting hole; 9. Civil engineering boundary line before demolition; 10. Civil engineering boundary line after demolition. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0022] Example 1 like Figures 1-5 As shown, the present invention proposes a method for rapid replacement of an air heat exchanger under a concrete platform of a steel loading machine, the method comprising the following steps: S1. Based on the civil engineering boundary line 9 before demolition and the civil engineering boundary line 10 after demolition, the concrete platform at the bottom of the steel loading machine is laid out and positioned. The area between the civil engineering boundary line 9 before demolition and the civil engineering boundary line 10 after demolition of the concrete platform is partially cut off to form a hoisting hole 8 surrounded by the cut concrete 6. The hoisting hole 8 extends to the top of the air heat exchanger 7. A movable steel platform with the size of the hoisting hole 8 is made. The movable steel platform is used to be embedded in the hoisting hole 8 to form a daily walking passage, and can be lifted away when the air heat exchanger 7 is replaced to form a vertical hoisting passage. S2. Install the movable steel platform into the lifting hole 8; S3. Remove the outer casing of the steel loading machine and vertically lift the movable steel platform embedded in the lifting hole 8 to expose the vertical lifting channel; S4. Disassemble the connecting elbow between the air heat exchanger 7 and the main pipeline, release the external pipeline constraints of the air heat exchanger 7, and use an overhead crane to lift the old air heat exchanger 7 vertically out through the vertical hoisting channel. S5. Use an overhead crane to vertically hoist the new air heat exchanger 7 to the installation position through the vertical hoisting channel, and then reinstall the connecting elbow. S6. Reinstall the movable steel platform into the lifting hole 8, and reinstall the steel machine casing. The following is a detailed explanation of the quick replacement method for the heat exchanger: In this embodiment, a lifting hole 8 is formed on the concrete platform at the bottom of the steel loading machine by partially cutting out a predetermined area, allowing the air heat exchanger 7 to pass vertically through. A movable steel platform is then configured so that the movable steel platform can be used as a walking passage in normal conditions, and as a removable temporary cover 3 when replacing the air heat exchanger 7. This provides a vertically penetrating lifting path for the air heat exchanger 7 without relying on the removal of surrounding related equipment, thus enabling its vertical lifting and replacement.

[0023] The rapid heat exchanger replacement method first pre-treats the concrete platform at the bottom of the steel loading machine. Based on the pre-demolition civil engineering boundary line 9 and the post-demolition civil engineering boundary line 10, the concrete area between them is cut away, creating a lifting hole 8 defined by the cut concrete 6. This lifting hole 8 is vertically aligned with the air heat exchanger 7, forming a vertical passageway through the concrete platform. Simultaneously, a movable steel platform with dimensions matching the lifting hole 8 is pre-fabricated. This platform, when embedded in the lifting hole 8, forms a complete walking support plane with the surrounding concrete platform.

[0024] After completing the aforementioned basic modifications, a movable steel platform is embedded in the hoisting hole 8, allowing construction personnel to safely pass through the concrete platform without affecting the daily operation of the steel loading machine. When it is necessary to replace the air heat exchanger 7, the outer casing of the steel loading machine is first removed to remove the obstruction of the hoisting path. Then, the movable steel platform is vertically lifted off the hoisting hole 8, fully exposing the pre-formed vertical through-passage, which serves as the entry and exit path for the vertical hoisting of the air heat exchanger 7. At this point, there are no obstructions above the air heat exchanger 7. Construction personnel only need to disassemble the connecting elbow between the air heat exchanger 7 and the main pipeline to remove its external pipeline constraints. The plant's overhead crane can then pass through this vertical hoisting channel to lift the old air heat exchanger 7 directly vertically upward from its installation position. Similarly, the new air heat exchanger 7 is also vertically lifted into the installation position by the overhead crane through the same vertical hoisting channel. After placement, the connecting elbow is reinstalled to restore the pipeline connection. Finally, the movable steel platform is reinstalled into the lifting hole 8 and returned to the outer shell of the steel loading machine, restoring the concrete platform and the steel loading machine to their complete structure. This method, through a combination of partial cutting to form a channel and temporary sealing with a removable platform, changes the replacement path of the air heat exchanger 7 from the traditional horizontal transport to vertical lifting, thus eliminating the need to dismantle adjacent equipment such as the gas heat exchanger and steam heat exchanger, significantly simplifying the core replacement process.

[0025] Example 2 like Figures 1-5 As shown, based on Embodiment 1, the rapid heat exchanger replacement method further includes a frame body 1, a supporting beam 2, a cover plate 3, a guardrail 4, and lifting lugs 5. The frame body 1 and the supporting beam 2 form a rigid skeleton. The cover plate 3 is laid on top of the frame body 1, the guardrail 4 is set on the outside of the frame body 1, and the lifting lugs 5 are set on both sides of the frame body 1. The size of the movable steel platform is consistent with the size of the lifting hole 8, and the movable steel platform is embedded in the lifting hole 8. The top surface of the cover plate 3 is flush with the top surface of the surrounding uncut concrete platform. The frame body 1 and the supporting beam 2 are formed by processing and welding H-beams. The lifting lugs 5 are welded to both sides of the frame body 1 for connecting the overhead crane hook. The cover plate 3 is a 6mm thick checkered steel plate, which is fully laid and welded on top of the frame body 1.

[0026] In step S1, a concrete wire cutting machine is used to cut the area of ​​the concrete platform between the pre-demolition civil engineering boundary line 9 and the post-demolition civil engineering boundary line 10 into sections, and the waste is removed; in step S4, before disassembling the connecting elbow, the fastening bolts of the connecting elbow between the air heat exchanger 7 and the main pipeline are removed, and the disassembled connecting elbow is lifted out and placed in place; in step S4, after the connecting elbow is completely removed and there is no external pipeline constraint, the old air heat exchanger 7 is lifted vertically out by an overhead crane through the lifting hole 8.

[0027] In this embodiment, in step S5, when reinstalling the connecting elbow, the flange sealing surface and gasket of the connecting elbow are checked to confirm that there is no damage or misalignment; in step S6, after the movable steel platform is reinstalled into the lifting hole 8, the energy medium is restored, a leak test is performed on all connection parts of the air heat exchanger 7, and the equipment is put into no-load test run. The following is a detailed description of the quick replacement method for the heat exchanger: In this embodiment, at the level of concrete platform modification, the pre-demolition civil engineering boundary line 9 and the post-demolition civil engineering boundary line 10 serve as the starting and ending boundaries of the excavation area, respectively, defining the specific scope of the partial excavation of the concrete platform. After the excavation operation, a lifting hole 8, formed by the cut concrete 6, is created in the original concrete platform within this area. The planar position of the lifting hole 8 is directly opposite the air heat exchanger 7 below, and its through-section size is larger than the horizontal projection size of the air heat exchanger 7 to ensure that the air heat exchanger 7 can pass through vertically without interference.

[0028] In terms of the structural configuration of the movable steel platform, the frame body 1 serves as the main load-bearing skeleton of the entire steel platform. Its outline dimensions on the plane are consistent with the opening dimensions of the hoisting hole 8. It is used to bear the vertical load borne by the platform and transfer it to the surrounding uncut concrete platform. The supporting beam 2 serves as an internal reinforcing member of the frame body 1. It is horizontally connected between the opposite sides of the frame body 1, dividing the internal space of the frame body 1 into several grid areas, which enhances the overall rigidity of the platform and distributes the load evenly. The cover plate 3 is fully laid and fixed above the frame body 1 and the supporting beam 2. Its top surface is flush with the top surface of the surrounding uncut concrete platform. When the steel platform is installed in the hoisting hole 8, the cover plate 3 and the surrounding concrete platform together form a continuous and flat walking support surface, which allows the steel loading machine and operators to pass normally. When the steel platform is hoisted away, the cover plate 3 is removed along with the frame body 1, and the hoisting hole 8 is fully opened. The guardrail 4 is installed around the outer perimeter of the frame body 1. Its height meets the safety protection specifications for industrial sites. When the movable steel platform is lifted away and placed in the storage location, the guardrail 4 provides safety protection for the exposed edges of openings, preventing personnel or objects from falling from the platform edges. The lifting lugs 5 are symmetrically arranged on opposite sides of the frame body 1, serving as connection nodes between the overhead crane hook and the steel platform. The symmetrical arrangement of the lifting lugs 5 on both sides ensures that the steel platform is subjected to balanced forces and maintains a stable posture during vertical lifting.

[0029] The frame body 1 and the supporting beams 2 are formed by welding HN700*300*13*24 H-beams to create a rigid skeleton, providing structural strength and load-bearing capacity. The cover plate 3 covers the upper surface of the skeleton, enabling both walking and sealing functions. The lifting lugs 5 serve as lifting force nodes, allowing the entire steel platform to be quickly lifted into or out of the lifting hole 8 by the overhead crane as a whole. The guardrails 4 provide fall protection around the opening after the platform is lifted out. When the steel platform is installed in the lifting hole 8, this combined structure acts as a removable filler for the concrete platform, achieving complete closure of the platform surface. When the steel platform is lifted out as a whole, the lifting hole 8 forms a vertical passage for the air heat exchanger 7, thus structurally ensuring that the air heat exchanger 7 can be directly and vertically lifted in and out by the overhead crane without any horizontal handling operations.

[0030] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A method for quickly replacing an air heat exchanger under a concrete platform of a steel loading machine, characterized in that, Includes the following steps: S1. Based on the civil engineering boundary line (9) before demolition and the civil engineering boundary line (10) after demolition, the concrete platform at the bottom of the steel loading machine is laid out and positioned. The area between the civil engineering boundary line (9) before demolition and the civil engineering boundary line (10) after demolition of the concrete platform is partially cut off to form a hoisting hole (8) surrounded by the cut concrete (6). The hoisting hole (8) extends to the top of the air heat exchanger (7). A movable steel platform with the size of the hoisting hole (8) is made. The movable steel platform is used to be embedded in the hoisting hole (8) to form a daily walking passage, and can be lifted away when the air heat exchanger (7) is replaced to form a vertical hoisting passage. S2. The movable steel platform is installed in the hoisting hole (8); S3. Remove the outer shell of the steel loading machine and vertically lift the movable steel platform embedded in the lifting hole (8) to expose the vertical lifting channel; S4. Disassemble the connecting elbow of the air heat exchanger (7) to the main pipeline, release the external pipeline constraints of the air heat exchanger (7), and use an overhead crane to lift the old air heat exchanger (7) vertically out through the vertical hoisting channel. S5. Using an overhead crane, the new air heat exchanger (7) is vertically hoisted to the installation position through the vertical hoisting channel, and the connecting elbow is reinstalled. S6. Reinstall the movable steel platform into the hoisting hole (8) and reinstall the steel loading machine shell.

2. The method for rapid replacement of the air heat exchanger under the concrete platform of a steel loading machine according to claim 1, characterized in that, The movable steel platform includes a frame body (1), a supporting beam (2), a cover plate (3), a guardrail (4), and lifting lugs (5). The frame body (1) and the supporting beam (2) form a rigid skeleton. The cover plate (3) is laid on top of the frame body (1). The guardrail (4) is set on the outside of the frame body (1). The lifting lugs (5) are set on both sides of the frame body (1).

3. The method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine according to claim 2, characterized in that, The dimensions of the movable steel platform are the same as those of the hoisting hole (8), and the movable steel platform is embedded in the hoisting hole (8). The top surface of the cover plate (3) is flush with the top surface of the surrounding uncut concrete platform.

4. The method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine according to claim 2, characterized in that, The frame body (1) and the supporting beam (2) are formed by welding H-beams. The lifting lugs (5) are welded to both sides of the frame body (1) and are used to connect the crane hook.

5. A method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine according to claim 2, characterized in that, The cover plate (3) is a 6mm thick patterned steel plate, which is fully welded on the top of the frame body (1).

6. A method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine according to claim 1, characterized in that, In step S1, a concrete wire cutting machine is used to cut the area of ​​the concrete platform between the pre-demolition civil engineering edge line (9) and the post-demolition civil engineering edge line (10) into sections, and the waste is removed.

7. A method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine according to claim 1, characterized in that, In step S4, before disassembling the connecting elbow, the fastening bolts of the air heat exchanger (7) and the connecting elbow of the main pipeline are removed, and the disassembled connecting elbow is lifted out and placed in place.

8. A method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine according to claim 1, characterized in that, In step S4, after the connecting elbow is completely removed and there are no external pipeline constraints, the old air heat exchanger (7) is vertically lifted out by the overhead crane through the hoisting hole (8).

9. A method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine according to claim 1, characterized in that, In step S5, when reinstalling the connecting elbow, check the flange sealing surface and gasket of the connecting elbow to confirm that there is no damage or misalignment.

10. A method for quickly replacing the air heat exchanger under the concrete platform of a steel loading machine according to claim 1, characterized in that, In step S6, after the movable steel platform is reinstalled into the hoisting hole (8), the energy medium is restored, a leak test is performed on all connection parts of the air heat exchanger (7), and the equipment is put into no-load test run.

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