Construction method for lifting and installing steel sleeve chimney shaped like Chinese character'pin '
By employing a reverse installation method involving ground-based segmented welding and overall modular lifting, combined with a hydraulic synchronous lifting system and computer control, the installation accuracy and safety issues of the triangular three-cylinder arrangement were resolved, achieving efficient and safe installation of the steel inner cylinder.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA CHEM ENG SECOND CONSTR
- Filing Date
- 2026-03-31
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies are insufficient to meet the installation accuracy requirements of steel inner cylinders in a triangular arrangement, resulting in problems such as cylinder collisions, poor synchronization, large welding workload, long construction period, and insufficient safety, especially in terms of poor construction flexibility in narrow spaces.
The inverted construction method, which involves ground-based segmented welding, overall modular lifting, and inverted welding at the cylinder opening, is adopted. Through a hydraulic synchronous lifting system, a computer control system, and a multi-point monitoring mode, the three cylinders are lifted in a coordinated manner. Combined with adjustable positioning fixtures and temporary rigid supports, the welding process and procedures are optimized and coordinated.
It achieves efficient and precise installation of the triangular three-cylinder structure, with synchronous deviation controlled within 2mm, reducing welding workload by 40%, reducing high-altitude work by 80%, improving construction efficiency by 60%, and ensuring construction safety and structural stability.
Smart Images
Figure CN122014049A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of chimney construction technology, specifically relating to a method for lifting and installing a triangular steel sleeve chimney. It is applicable to the inverted lifting and installation of the inner steel cylinder of an ultra-high, large-tonnage titanium-steel composite plate three-tube sleeve chimney, and is especially suitable for industrial chimney construction scenarios with limited working space inside reinforced concrete outer cylinders and high requirements for installation accuracy and construction safety. Background Technology
[0002] With the continuous upgrading of industrial environmental protection requirements in sectors such as power and chemicals, and the increasing stringency of flue gas emission treatment standards, the application of high-height, heavy-tonnage titanium-steel composite plate three-tube sleeve chimneys with steel inner cylinders is becoming increasingly widespread. These steel inner cylinders can reach heights of over 150m and weigh up to 200T per cylinder. The three inner cylinders are arranged in a triangular pattern inside a reinforced concrete outer cylinder, placing stringent requirements on installation precision and structural stability. Traditional construction methods and existing inverted lifting technologies are insufficient to meet these demands.
[0003] In existing technologies, such as the steel sleeve chimney inverted installation method disclosed in patent CN202210826578.7, although the inverted installation method reduces some high-altitude work, it still has many defects: First, it does not optimize the lifting points for the spatial characteristics of the triangular three-cylinder arrangement, making it easy for the cylinders to collide with each other during the lifting process, and large hoisting equipment cannot operate in the narrow concrete outer cylinder, resulting in poor construction flexibility; Second, the synchronous control precision of the lifting system is insufficient, using a single synchronous control unit without an independent cylinder monitoring and adjustment module, resulting in a large synchronous error and failing to meet the synchronous lifting requirements of the triangular three-cylinder arrangement; Third, it continues to use 2-3m The fixed-height cylindrical sections, without the design of adjustable standard sections that take into account the processing characteristics of titanium-steel composite plates, result in a large amount of welding work and a lengthy construction period. Fourth, the configuration of steel strands and the load-bearing calculation of the lifting platform lack scientific basis, and the tensioning of steel strands is not synchronized, making the lifting platform prone to deformation and collapse risks. Fifth, the coordination of processes is poor. The anti-corrosion and heat preservation processes need to be carried out in a concentrated manner after all the cylindrical sections are installed. The construction of the three cylinders interferes with each other and cannot achieve assembly line operation. Sixth, the high-altitude assembly welding is greatly affected by environmental factors, making it difficult to control the welding quality and prone to weld defects, which affect the safety of the cylinder structure.
[0004] Therefore, there is an urgent need to develop a construction method for lifting and installing triangular steel sleeve chimneys that is adapted to the characteristics of the triangular layout, has high synchronization, controllable construction precision, adequate safety protection, and efficient process coordination, so as to solve the shortcomings of existing technologies. Summary of the Invention
[0005] This invention overcomes the shortcomings of existing technologies and provides a construction method for lifting and installing a triangular steel sleeve chimney. By optimizing the configuration of the lifting system and the synchronous control and monitoring mode, it achieves efficient and precise installation of the triangular three-sleeve chimney, meeting the construction needs of tall and heavy titanium-steel composite plate chimneys.
[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a construction method for lifting and installing a triangular steel sleeve chimney, characterized by adopting an inverted construction method of ground segmented welding, overall modular lifting, and inverted welding of the chimney opening, with a hydraulic lifting base set on a permanent steel platform at the top of the reinforced concrete outer cylinder, and the following steps are performed in sequence: S1: Construction preparation and lifting system installation: The permanent steel platform undergoes load-bearing grading calculations and is reinforced with a steel mesh weld. After reinforcement, a load test is conducted at 1.1 times the design load. An assembly platform is built on the steel profiles at the zero-meter level of the chimney. The platform is equipped with tracks, traction equipment, and adjustable positioning clamps, with reserved maintenance and emergency access. A hydraulic synchronous lifting system is installed along the axis of each inner steel cylinder. Each inner steel cylinder is equipped with multiple through-type jacks, and each jack is equipped with multiple high-strength, low-relaxation steel strands. The pump station cluster of the hydraulic synchronous lifting system consists of an independent pump station for each jack and a central control pump station. The computer synchronous control system is connected to multiple sets of sensors. Multiple sets of verticality monitoring points are set for each inner cylinder on the permanent steel platform, the middle of the concrete outer cylinder, and the bottom assembly platform. A comprehensive safety protection system from top to middle to bottom is built synchronously. S2: Prefabrication and horizontal transportation of cylindrical sections. Prefabricated adjustable height titanium steel composite plate standard sections are installed at both ends of the standard sections with positioning structures and butt joint bevels. After welding, ultrasonic and radiographic non-destructive testing is performed. The prefabricated standard sections are horizontally transported to the assembly platform via rails and traction equipment and fixed by adjustable positioning clamps. S3: The first section is hoisted and fixed to the top section. A standard section at a fixed height is selected as the top section. After dimensional verification, surface cleaning, and grinding of the butt joint bevel, lifting lugs of the same material as the cylinder are welded to the top. The top section is then hoisted to the design elevation at a uniform speed using a lifting system. The hoisting process is paused periodically to verify verticality. The axis of the top section coincides with the design axis. Temporary rigid supports connected by anchors are installed on the inner wall of the concrete outer cylinder at the designated elevation. At the same time, an adjustable positioning device is installed on the outer side of the top section to form a double fixing structure. After fixing, the stress test is performed on the connection parts. S4: Cyclic lifting welding operation, the lower end of the steel strand of the hydraulic lifting system is double-safely connected to the upper end of the top section, the adjustable positioning device is removed while the temporary rigid support is retained, and the three cylinders are lifted in a uniform speed by the computer synchronous control system. The lifting height is the height of a single standard section module, and the synchronous deviation is controlled within the accuracy requirements. The new standard section is transported to the lower part of the lifting space and precisely assembled by the hydraulic drive assembly device. After assembly, it is fixed by a temporary positioning structure. Gas shielded welding equipment is used to perform welding in a single-sided welding and symmetrical welding method without backing plates. After the weld is inspected and qualified, the connection point of the lifting system is transferred to the upper end of the new section, the temporary positioning structure is removed, and the collaborative lifting operation steps to the inspection are repeated. S5: The auxiliary processes are carried out simultaneously. The three inner cylinders are operated in an assembly line mode. The bottom assembly platform is responsible for welding the standard sections. The middle platform of the concrete outer cylinder is responsible for anti-corrosion and heat preservation construction of the cylinder sections that have been lifted and passed the inspection. After sandblasting and rust removal on the outer wall of the cylinder, anti-corrosion coating is applied in multiple layers. The heat preservation construction uses a heat preservation layer composed of heat preservation felt, metal wire mesh, protective foil layer and fasteners. S6: Final positioning and accessory installation. After the total height of the cylinder reaches the design requirements, first comprehensively check to ensure the verticality of the cylinder and the deviation of the axis. Then, lift the inner steel cylinder to the designated position above the design elevation. Lower the inner steel cylinder to the design elevation at low speed and lock the lifting system after it is in place. Weld steel brackets to the bottom of the cylinder. The brackets are fully welded to the cylinder and the bottom rigid support. Then, weld the reinforcing rings symmetrically. After welding the brackets and reinforcing rings, perform non-destructive testing and stress testing. Dismantle the lifting system in the order of steel strand → jacks → pump station cluster → lifting load-bearing beam. When dismantling the steel strands, use a staged unloading method to complete the overall project.
[0007] In S1, the lifting load-bearing beam of the hydraulic synchronous lifting system is fully welded to the platform reinforcement structure. The computer synchronous control system automatically stops and adjusts when the deviation exceeds the standard or the load is abnormal.
[0008] The comprehensive inspection of the prefabricated standard sections in S2 includes comprehensive testing of dimensional accuracy, roundness, weld quality, and material properties. Anti-slip mats are laid on the surface of the steel transition platform at the bottom of the concrete outer cylinder.
[0009] The S3 top section is connected to the steel strands of the lifting system via special anchors. The anchors of the temporary rigid support are firmly connected to the concrete outer cylinder, and the double-fixed structure is free from loosening and deformation.
[0010] Before the three cylinders in S4 are lifted in tandem, it is confirmed that the lifting system has good synchronization and the steel strands are under uniform stress. The pairing accuracy of the hydraulic drive pairer is monitored in real time by a laser ranging device.
[0011] In S4, welding operations utilize a liftable suspended construction platform, with dedicated personnel monitoring welding temperature and weld formation and adjusting welding process parameters promptly.
[0012] The quality review of anti-corrosion and thermal insulation construction in S5 includes special tests on the thickness and adhesion of the anti-corrosion layer, as well as the thickness and fixing firmness of the thermal insulation layer.
[0013] After the inner steel cylinder of S6 is placed, a dual fixing mode of bracket welding and reinforcing ring reinforcement is adopted. During the welding process, process measures are taken to reduce the impact of welding stress on the cylinder structure.
[0014] Compared with existing technologies, the advantages of this invention are as follows: This invention achieves coordinated lifting of three triangular cylinders using a customized hydraulic synchronous lifting system, with synchronous deviation controlled within 2mm, avoiding interference between cylinders; the design of adjustable standard sections ranging from 6.0 to 10.5m significantly reduces welding workload and shortens the construction cycle by more than 40%; the adoption of a "ground welding and high-altitude inversion" construction method reduces high-altitude work by 80%, lowering operational risks; combined with a dedicated welding process for titanium-steel composite plates and a closed-loop non-destructive testing system, the weld pass rate reaches 100%, ensuring the structural safety of the cylinder; the adoption of a three-dimensional assembly line operation mode enables simultaneous assembly welding and anti-corrosion insulation processes, improving construction efficiency by more than 60%; precise platform calculation and reinforcement, and steel strand configuration enhance the load-bearing safety during construction; and the final precise placement and dual permanent fixing mode ensure the long-term operational stability of the cylinder. The construction method and supporting system of this invention are suitable for narrow working spaces inside reinforced concrete outer cylinders, do not require large hoisting equipment, have high construction flexibility, and are applicable to the construction of tall, heavy-duty triangular steel sleeve chimneys in the power and chemical industries, and have significant engineering application value. Attached Figure Description
[0015] The present invention will now be further described with reference to the accompanying drawings.
[0016] Figure 1 To improve the system's layout on the top platform; Figure 2 This is a schematic diagram of a standard section ground transportation device; Figure 3 This is a schematic diagram of the steel inner cylinder installation. Figure 4 This is a schematic diagram of the measurement of the straightness of a pair of chimneys; In the diagram, 1-100T through-type jack, 2-lifting load-bearing beam, 3-light rail, 4-flatbed car, 5-steel strand, 6-30.0m level platform, 7-steel ruler, 8-steel inner cylinder, 9-reinforced concrete outer cylinder, 10-anti-sway platform, 11-baseline plumb line. Detailed Implementation
[0017] A method for lifting and installing a triangular steel sleeve chimney involves setting up a hydraulic lifting base on a permanent steel platform at an elevation of 144m on top of the reinforced concrete outer cylinder 9. The construction employs an inverted installation method, which includes "ground-based segmented welding, overall modular lifting, and inverted welding at the chimney opening." The specific steps are as follows: S1: Construction Preparation and Lifting System Installation This step focuses on completing platform load-bearing capacity calculations, enhancing system customization configurations, and implementing layered reinforcement, laying the foundation for the safety and accuracy of subsequent construction. It is specifically divided into the following sub-steps: S1.1: Pre-construction survey and scheme verification: A comprehensive test and verification of the structural strength of the reinforced concrete outer cylinder 9 and the load-bearing capacity of the permanent steel platform at the 144m elevation were conducted. Considering the weight of a single cylinder (200T), the lifting stroke, and the spacing of the three cylinders in a triangular arrangement, software simulation was used to analyze the stress distribution, deformation, and stability of the platform during the lifting process, identifying the platform's weak points. A "graded verification" model was adopted to separately verify the platform's own load-bearing capacity, the dynamic load during the lifting equipment's operation, and the additional stress during the cylinder lifting process, ensuring that the platform's load-bearing safety factor is not less than 3.5.
[0018] S1.2: Assembly Platform Construction: An inner cylinder assembly platform is constructed at the bottom (zero-meter level) inside the reinforced concrete chimney. The platform body 4 is constructed using HW300×300 steel and integrates transportation channels, cylinder section positioning, and assembly / welding functions. Light rails 3 are laid on the platform surface, coupled with electric hoist traction equipment, forming a "transportation-positioning-assembly" assembly line operation channel. Adjustable positioning clamps are installed on the platform; these clamps are hydraulically driven and can be precisely adjusted according to the cylinder section diameter to ensure that the center deviation of the assembled cylinder sections is ≤2mm. The platform includes a maintenance passage and an emergency exit, balancing construction efficiency and safety.
[0019] S1.3: Platform Reinforcement: Based on preliminary calculations, targeted reinforcement was carried out on the 144m elevation permanent steel platform, focusing on the area where the lifting equipment is located and the platform beam joints. HW300×300 steel was used to weld and reinforce the existing platform beams, forming a grid-like load-bearing structure to ensure the platform can withstand a static load of 300T and the dynamic load during the lifting process. After reinforcement, a load test was conducted on the platform, applying a 330T load (1.1 times the design load) and continuously monitoring for 24 hours. Only after confirming that the platform showed no deformation or cracks could the next step of construction proceed.
[0020] S1.4: Installation of Hydraulic Synchronous Lifting System: On the 144m high-level permanent steel platform, corresponding to the axial position of each inner steel cylinder 8, a hydraulic synchronous lifting system is installed. This system is a customized design and specifically includes lifting load-bearing beam 2, 100T through-type jack 1 (LSD100 dedicated), pump station cluster, computer synchronous control system, and steel strand assembly. (1) Installation of Lifting Bearing Beam 2: It is formed by welding of steel profiles and is precisely positioned and installed according to the axial position of each inner cylinder. The bearing beam and the platform reinforcement structure are connected by full welding. The weld height is not less than the thickness of the steel profile. Non-destructive testing is carried out after welding. Each inner cylinder corresponds to a set of bearing beams. The three sets of bearing beams are arranged symmetrically in a triangular shape. The spacing is consistent with the design spacing of the three cylinders to avoid the problem of mutual interference between the three cylinders during the lifting process.
[0021] (2) Jack arrangement: Each inner cylinder is equipped with 4 100T through-type jacks (LSD100 dedicated), symmetrically arranged around the inner cylinder axis to form a square lifting array, ensuring uniform force on the cylinder during lifting. Before installation, the jacks are thoroughly inspected and adjusted to ensure that the hydraulic system is leak-free and the stroke accuracy meets the requirements (stroke error ≤ 0.5mm); during installation, the verticality of the jacks is adjusted to ensure that the jack axis is parallel to the inner cylinder axis, with a deviation ≤ 1mm.
[0022] (3) Pump station cluster configuration: Each jack corresponds to an independent pump station, and a central control pump station is set up to form a pump station cluster mode of "independent control + centralized management and control". This mode can realize the independent adjustment of a single jack and facilitate the correction of lifting synchronization deviation. The pump station and the jack are connected by a high-pressure oil pipe. The oil pipe is arranged to avoid the working passage and is properly protected.
[0023] (4) Computer synchronous control system debugging: Customized synchronous control software is adopted, which has three functions: "real-time monitoring, automatic adjustment and emergency shutdown". The system is connected to multiple sets of sensors to collect the lifting speed, stroke, load and verticality data of each jack in real time. The synchronization deviation is calculated by algorithm analysis. When the synchronization deviation exceeds 2mm, the system automatically adjusts the lifting speed of the corresponding jack. At the same time, an emergency shutdown button is set up so that the machine can be stopped manually or automatically in case of abnormality.
[0024] (5) Steel strand assembly installation: Each jack is equipped with 5 high-strength, low-relaxation φ17.8mm steel strands. The tensile strength of a single steel strand is ≥1860MPa, the breaking strength is ≥260kN, and the safety factor reaches 3.2. Rust removal and flaw detection are carried out before lowering the steel strands. A special guiding device is used during the lowering process to avoid friction damage. After the steel strands are threaded, each bundle is pre-tensioned with a 3T chain hoist to ensure that the force on each bundle of steel strands is consistent during lifting, and the deviation of the lifting length is ≤1mm.
[0025] S1.5: Auxiliary System Installation: The basic components of the monitoring system and safety protection system are installed simultaneously. The monitoring system sets verticality monitoring points at the 144m platform, the middle of the reinforced concrete outer cylinder (75m elevation), and the bottom assembly platform. Each inner cylinder has 4 monitoring points, using a combination of laser rangefinder and plumb line monitoring. The safety protection system sets guardrails and fall protection nets on the top platform, sets an anti-sway platform 10 in the middle, and sets a safety protection shed at the bottom to construct a comprehensive protection system.
[0026] S2: Prefabrication of cylindrical sections and horizontal ground transportation This step optimizes the prefabrication specifications and transportation plan for the cylindrical sections, achieving integrated operations of "factory prefabrication - efficient transportation - precise placement," and is specifically divided into the following sub-steps: S2.1: Adjustable Standard Section Prefabrication: Titanium-steel composite plate cylindrical sections are prefabricated in the factory, designed with adjustable heights from 6.0m to 10.5m for single-cylinder standard sections, which can be flexibly adjusted according to on-site construction progress and welding equipment capabilities. Standard section prefabrication utilizes a dedicated plate rolling machine, with rolling accuracy controlled within ±1mm, ensuring a cylindrical section roundness deviation ≤3mm. The cylindrical section butt joints are welded using submerged arc welding, with weld quality meeting the Class I weld requirements of GB / T 12469-2016 standard. After welding, non-destructive testing (ultrasonic testing + radiographic testing) is performed, and only qualified sections are shipped. Positioning pins and butt joint bevels are installed at both ends of the standard section, with a bevel angle designed at 30°±2° for easy on-site assembly and welding.
[0027] S2.2: Standard Section Factory Inspection and Packaging: Before leaving the factory, the standard section undergoes a comprehensive quality inspection, including indicators such as dimensional accuracy, roundness, weld quality, and material performance. After passing the inspection, it is packaged in a waterproof and impact-resistant manner, and protective padding is affixed to the inner wall of the section to prevent damage to the surface of the cylinder during transportation.
[0028] S2.3: On-site transportation planning: Plan the transportation route in advance, use concrete hardening treatment, and the bearing capacity shall not be less than 30T; set a transition platform at the bottom opening of the concrete outer cylinder to connect the flatbed truck 4 with the internal track. The transition platform is built with steel profiles and the surface is covered with anti-slip mats.
[0029] S2.4: On-site transportation of standard sections: The standard sections are transported to the bottom opening of the chimney using flatbed truck 4. During transportation, special clamps are used for fixation, and flexible pads are placed at the contact points between the clamps and the chimney body. The transportation speed is controlled within 5km / h. After arriving at the opening, the standard sections are horizontally transported to the designated work position on the assembly platform inside the outer cylinder using light rail tracks and electric hoist traction equipment (traction force ≥5T). After transportation to the designated position, they are fixed with adjustable positioning clamps to ensure that the axis of the standard section coincides with the positioning baseline of the assembly platform.
[0030] S3: First section hoisting and top section fixing This step optimizes the top section positioning and temporary fixing scheme, and is specifically divided into the following sub-steps: S3.1: Top Section Selection and Pre-treatment: A standard section with a height of 6.0m is selected as the top section. After being transported to the assembly platform, the dimensions are checked and the surface is cleaned again. The joint bevel is ground. A special lifting lug is welded to the top of the top section. The lifting lug is made of titanium steel composite plate of the same material as the cylinder. The welding is full welding. After the welding is completed, non-destructive testing is carried out to ensure that the load-bearing safety factor of the lifting lug is ≥4.0.
[0031] S3.2: Top Section Lifting and Positioning: Connect the steel strands of the lifting system to the lifting lugs and secure them with specialized anchors. Start the lifting system and slowly lift the top section to the design elevation of 150m, controlling the lifting speed to within 0.5m / min. Pause every 1m to check the verticality. After reaching the design elevation, adjust the position of the top section to ensure that its axis coincides with the design axis, with an axis deviation ≤2mm.
[0032] S3.3: Temporary Fixation of the Top Section: A dual fixing scheme of "temporary rigid support + adjustable positioning device" is adopted. Temporary rigid supports are installed on the inner wall of the concrete outer cylinder (at an elevation of 148m). The supports are welded from structural steel and connected to the concrete outer cylinder using chemical anchors with an insertion depth ≥150mm. Simultaneously, an adjustable positioning device is installed on the outer side of the top section, and the fit between the positioning block and the reinforced concrete outer cylinder 9 is adjusted hydraulically. After temporary fixing is completed, stress tests are conducted on the connection between the support structure and the top section to confirm there is no loosening or deformation.
[0033] S4: Cyclic lifting welding operation This step optimizes and improves the process and welding technology to achieve a closed-loop operation of "improvement-assembly-welding-inspection", which is specifically divided into the following sub-steps: S4.1: Lifting System Connection Conversion: Connect the lower end of the steel strand of the hydraulic lifting system to the upper end of the top section using a special lifting tool, and use double insurance for fixation; remove the adjustable positioning device that temporarily fixes the top section, and retain the temporary rigid support; check the synchronization of the lifting system and the stress state of the steel strand again, and start the lifting system after confirming that there are no abnormalities.
[0034] S4.2: Synchronous Lifting of the Cylindrical Units: A three-cylinder coordinated lifting mode is adopted. A computer-controlled synchronous control system links and controls the three lifting systems, maintaining a lifting speed of 0.5-1.0 m / min and a lifting height equal to the height of one standard module section. During the lifting process, the monitoring system collects relevant data in real time, controlling the synchronization deviation within 2 mm. Automatic shutdown and adjustment are triggered if deviation exceeds the limit or abnormal load occurs.
[0035] S4.3: Standard Section Positioning and Precise Assembly: After lifting to the designated height, the lifted cylinder is temporarily locked using the lifting system. The next standard section is transported to the space below the lifted section via a horizontal transport system, and its position is adjusted to ensure the axes coincide. A hydraulically driven assembly device is used for precise assembly, and a laser rangefinder is used to monitor the docking gap and roundness. The docking gap is controlled within 2-4mm, and the roundness deviation is ≤3mm. The relative positions of the three cylinders are checked simultaneously to ensure that the distance deviation between the three cylinders is ≤5mm. After assembly, temporary positioning pins are used for fixation.
[0036] S4.4: Customized Welding Operations: Adaptable welding processes are employed based on the material characteristics of the titanium-steel composite plate. (1) Welding equipment selection: Carbon dioxide gas shielded welding equipment is used, along with ERNiCrMo-3 titanium steel composite plate special welding wire, equipped with windproof device, suitable for high-altitude and enclosed space welding.
[0037] (2) Optimization of welding process parameters: The single-sided welding process without backing plate is adopted, the welding current is controlled at 180-220A, the welding voltage is controlled at 22-26V, the welding speed is controlled at 8-12cm / min, and the interpass temperature is controlled below 150℃.
[0038] (3) Welding operation implementation: A self-made suspended construction platform is used, and a 30m platform is used to set up lifting points. An electric hoist is used to drive the lifting. During welding, a symmetrical welding method is adopted. Welding starts simultaneously from four welding points evenly distributed around the circumference of the cylinder and gradually moves towards the middle. A dedicated person is assigned to monitor the welding temperature and weld formation and adjust the welding parameters in a timely manner.
[0039] S4.5: Non-destructive testing and repair of welds: After welding is completed, the weld appearance is first inspected, and then a dual inspection mode of ultrasonic testing + radiographic testing is adopted to achieve 100% inspection coverage. If weld defects are found, they are marked, ground off, re-welded, and inspected again until they pass, forming a closed-loop control.
[0040] S4.6: Lifting System Connection Conversion and Cyclic Operation: After the weld inspection is qualified, the lower connection point of the lifting system is transferred to the upper end of the newly welded standard section module, the temporary positioning pin is removed, and the steps from S4.2 to S4.5 are repeated to achieve the inverted extension of the cylinder.
[0041] The straightness measurement of chimney segments during the assembly process is crucial. Only by ensuring the straightness of adjacent segments can the straightness of the chimney be guaranteed in the end. The straightness measurement during the assembly process mainly uses the length of three or more chimney segments, that is, beyond a length of 12 meters. Using the principle of two-point alignment, the vertical distance from the outer wall of the steel chimney to two radially perpendicular reference lines 11 is measured with a steel ruler 7 to determine whether the assembled segment and the lifting segment are on a straight line.
[0042] S5: Ancillary processes are interspersed synchronously. This step adopts a three-dimensional assembly line operation mode to achieve simultaneous assembly welding, corrosion protection, and heat preservation processes, and is specifically divided into the following sub-steps: S5.1: Process Coordination Planning: Formulate a process coordination plan of "synchronous construction and layered operation". The three inner cylinders adopt the flow operation mode, using the same set of lifting system for relocation or setting up multiple sets of lifting systems with the same configuration for synchronous construction; the bottom assembly platform is responsible for the standard section assembly and welding, and the middle part (30.0m layer platform) is responsible for the anti-corrosion and heat preservation construction of the lifted cylinder section, forming a three-dimensional flow operation system.
[0043] S5.2: Corrosion Protection Construction Proceeds Simultaneously: While welding the new standard section, corrosion protection construction is carried out on the outer wall of the cylinder that has been lifted and whose welds have passed inspection. Before construction, the cylinder surface is sandblasted to remove rust, achieving a rust removal grade of Sa2.5 and a surface roughness controlled at 40-70μm. A special anti-corrosion coating for titanium-steel composite plates is used, applied in two layers: the first layer is 60-80μm thick, and the second layer is 80-100μm thick. After spraying, the coating is cured for no less than 24 hours.
[0044] S5.3: Simultaneous and Interleaved Insulation Construction: Insulation construction is carried out on the 30.0m platform 6, or it can be constructed on the ground according to site requirements, with pre-reserved joint positions. The insulation layer of the steel inner cylinder 8 and the steel flue consists of ultra-fine glass wool felt, galvanized steel wire mesh, aluminum foil, and stainless steel fastening straps or studs. The thickness of the insulation layer is adjusted according to design requirements (usually 100-150mm). During construction, ultra-fine glass wool felt, galvanized steel wire mesh, and aluminum foil are laid in sequence to ensure that the insulation layer is flat and firm.
[0045] S5.4: Process Quality Verification: After each section of anti-corrosion and insulation construction is completed, a quality verification shall be conducted to check the thickness and adhesion of the anti-corrosion layer and the thickness and fixation of the insulation layer. After the verification is qualified, a construction record shall be made to ensure that the process is traceable.
[0046] S6: Final positioning and accessory installation This step optimizes the placement and permanent fixation plan, and is divided into the following sub-steps: S6.1: Lifting the Cylinder to the Design Height: Once all standard section modules are installed and the total cylinder length reaches 150m, stop the cyclic operation and comprehensively check the cylinder's verticality, axial deviation, and weld quality to ensure all indicators meet design requirements (total height verticality deviation ≤100mm, axial deviation ≤5mm, weld non-destructive testing pass rate 100%). After passing the check, slowly lift the inner steel cylinder 8 to 100mm above the design elevation and then pause the lifting.
[0047] S6.2: Precise Positioning Adjustment: Using a "tiered adjustment and multi-point verification" method, the inner steel cylinder 8 is slowly lowered to the design elevation, with the lowering speed controlled within 0.3m / min. The lowering is paused and verified every 10mm to ensure precise positioning. After positioning is complete, a comprehensive verification is performed again to confirm that all indicators meet the requirements before locking the lifting system.
[0048] S6.3: Permanent Fixing Construction: A dual fixing method is adopted, combining corbel welding with reinforcing ring reinforcement. First, corbels are welded to the bottom of the cylinder. The corbels are made of structural steel and are fully welded to the cylinder and the bottom rigid support. After welding, non-destructive testing is performed. Then, reinforcing rings are welded using a symmetrical welding method to reduce welding stress. After permanent fixing is completed, stress testing is performed on the connection points.
[0049] S6.4: Lifting System Dismantling: After the permanent fixing inspection is passed, the lifting system shall be dismantled in the following order: "steel strand → jacks → pump station cluster → lifting load-bearing beam". When dismantling the steel strands, a staged unloading method shall be used to gradually release the prestress; protective measures shall be taken during the dismantling process to prevent equipment parts from falling; the dismantled equipment parts shall be cleaned, inspected, and stored promptly.
[0050] S6.5: Installation of Accessories and Adjustment of Anti-sway Devices: Install accessories such as the top cover plate and surge arrester. The top cover plate should be made of the same material as the cylinder and welded in place. The surge arrester should be installed according to electrical specifications to ensure proper grounding. For flue interface sections, pre-drill holes or install them later. After drilling, promptly perform anti-corrosion and insulation treatment. Install all anti-sway devices and adjust their tightness to ensure that they can limit cylinder swaying without affecting thermal expansion and contraction. After installation, conduct a sway test.
[0051] S6.6: Final Acceptance: After all construction procedures are completed, a comprehensive final acceptance shall be organized. The acceptance shall include the accuracy of the cylinder dimensions, verticality, weld quality, anti-corrosion and insulation quality, accessory installation quality, and the removal of safety protection facilities. A final acceptance report shall be issued after the acceptance is qualified before the cylinder can be put into use.
[0052] III. Construction System This invention also relates to a construction system for the above-described method, specifically designed for the characteristics of a three-cylinder lifting system in a triangular configuration, enabling multi-system collaborative operation, and specifically including: 1. High-altitude hydraulic lifting base station system: Located on a permanent steel platform at an elevation of 144m on top of the reinforced concrete outer cylinder 9, corresponding to three steel inner cylinders 8 arranged in a triangular pattern. Each inner cylinder is equipped with an independent lifting base station, and the three base stations are arranged symmetrically in a triangular pattern. Each base station includes a lifting load-bearing beam 2, four LSD100 type 100T through-hole jacks 1, a pump station cluster, and a computer synchronous control system. The lifting load-bearing beam 2 is fully welded to the platform reinforcement structure, and the weld height is not less than the thickness of the steel section. The pump station cluster adopts an "independent control + centralized management" mode. The computer synchronous control system is connected to a laser rangefinder and stress sensor, which can realize synchronous adjustment and emergency handling of the three cylinders in coordinated lifting, and has real-time monitoring, automatic adjustment, and emergency shutdown functions.
[0053] 2. Ground / Bottom Assembly Platform System: Located at the zero-meter level at the bottom of the chimney, it is constructed using HW300×300 steel and has integrated functions of transportation, rotation, assembly, and welding. The platform surface is laid with light rails and equipped with adjustable hydraulic positioning clamps and electric hoist traction equipment with a traction force of ≥5T. It has reserved maintenance passages and emergency exits and can be adapted to precise positioning of standard sections and assembly line operations.
[0054] 3. Horizontal transport system: including flexible clamp flatbed trolley 4, light rail track and electric hoist traction equipment with traction force ≥5T, connecting the bottom opening and the assembly platform to achieve stable and precise transport of standard sections.
[0055] 4. Cylinder alignment and stabilization system: including multiple layers of temporary guide wheels, adjustable positioning device and temporary rigid support. The temporary guide wheels limit the horizontal displacement of the cylinder, the adjustable positioning device achieves precise positioning, and the temporary rigid support is used for temporary fixation of the top section to ensure improved stability.
[0056] 5. Monitoring System: The system adopts a multi-point linkage monitoring mode, including a verticality monitoring module, a lifting synchronization monitoring module, and a structural stress monitoring module. Monitoring points are set at the top platform, the middle 75m elevation, and the bottom assembly platform. Laser rangefinders, plumb line monitors, and stress sensors are used to collect data in real time and transmit it to the synchronization control system.
[0057] 6. Safety Protection System: Construct a comprehensive protection system from top to middle to bottom. The top platform is equipped with guardrails, fall protection nets and load monitoring devices. The middle section is equipped with an anti-sway platform 10 and a high-altitude work protection basket. The bottom section is equipped with a safety protection shed and emergency passage. Gas detection devices are also provided to monitor the gas concentration in the work area.
[0058] 7. Welding and Corrosion Protection & Thermal Insulation Auxiliary System: Includes special welding equipment for titanium steel composite panels, self-made suspended construction platform, anti-corrosion spraying equipment and thermal insulation laying tools. The welding equipment is equipped with windproof devices and uses ERNiCrMo-3 special welding wire for titanium steel composite panels. It is suitable for single-sided welding process without backing plate and can meet the welding needs of titanium steel composite panels in enclosed spaces and at high altitudes.
[0059] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Those skilled in the art can modify or improve the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.
Claims
1. A method for lifting and installing a triangular steel sleeve chimney, characterized in that, The construction method employs ground-based segmented welding, modular lifting, and inverted welding at the cylinder opening. A hydraulic lifting base is established on a permanent steel platform at the top of the reinforced concrete outer cylinder, and the following steps are executed sequentially: S1: Construction preparation and lifting system installation: The permanent steel platform undergoes load-bearing grading calculations and is reinforced with a steel mesh weld. After reinforcement, a load test is conducted at 1.1 times the design load. An assembly platform is built on the steel profiles at the zero-meter level of the chimney. The platform is equipped with tracks, traction equipment, and adjustable positioning clamps, with reserved maintenance and emergency access. A hydraulic synchronous lifting system is installed along the axis of each inner steel cylinder. Each inner steel cylinder is equipped with multiple through-type jacks, and each jack is equipped with multiple high-strength, low-relaxation steel strands. The pump station cluster of the hydraulic synchronous lifting system consists of an independent pump station for each jack and a central control pump station. The computer synchronous control system is connected to multiple sets of sensors. Multiple sets of verticality monitoring points are set for each inner cylinder on the permanent steel platform, the middle of the concrete outer cylinder, and the bottom assembly platform. A comprehensive safety protection system from top to middle to bottom is built synchronously. S2: Prefabrication and horizontal transportation of cylindrical sections. Prefabricated adjustable height titanium steel composite plate standard sections are installed at both ends of the standard sections with positioning structures and butt joint bevels. After welding, ultrasonic and radiographic non-destructive testing is performed. The prefabricated standard sections are horizontally transported to the assembly platform via rails and traction equipment and fixed by adjustable positioning clamps. S3: The first section is hoisted and fixed to the top section. A standard section at a fixed height is selected as the top section. After dimensional verification, surface cleaning, and grinding of the butt joint bevel, lifting lugs of the same material as the cylinder are welded to the top. The top section is then hoisted to the design elevation at a uniform speed using a lifting system. The hoisting process is paused periodically to verify verticality. The axis of the top section coincides with the design axis. Temporary rigid supports connected by anchors are installed on the inner wall of the concrete outer cylinder at the designated elevation. At the same time, an adjustable positioning device is installed on the outer side of the top section to form a double fixing structure. After fixing, the stress test is performed on the connection parts. S4: Cyclic lifting welding operation, the lower end of the steel strand of the hydraulic lifting system is double-safely connected to the upper end of the top section, the adjustable positioning device is removed while the temporary rigid support is retained, and the three cylinders are lifted in a uniform speed by the computer synchronous control system. The lifting height is the height of a single standard section module, and the synchronous deviation is controlled within the accuracy requirements. The new standard section is transported to the lower part of the lifting space and precisely assembled by the hydraulic drive assembly device. After assembly, it is fixed by a temporary positioning structure. Gas shielded welding equipment is used to perform welding in a single-sided welding and symmetrical welding method without backing plates. After the weld is inspected and qualified, the connection point of the lifting system is transferred to the upper end of the new section, the temporary positioning structure is removed, and the collaborative lifting operation steps to the inspection are repeated. S5: The auxiliary processes are carried out simultaneously. The three inner cylinders are operated in an assembly line mode. The bottom assembly platform is responsible for welding the standard sections. The middle platform of the concrete outer cylinder is responsible for anti-corrosion and heat preservation construction of the cylinder sections that have been lifted and passed the inspection. After sandblasting and rust removal on the outer wall of the cylinder, anti-corrosion coating is applied in multiple layers. The heat preservation construction uses a heat preservation layer composed of heat preservation felt, metal wire mesh, protective foil layer and fasteners. S6: Final positioning and accessory installation. After the total height of the cylinder reaches the design requirements, first comprehensively check to ensure the verticality of the cylinder and the deviation of the axis. Then, lift the inner steel cylinder to the designated position above the design elevation. Lower the inner steel cylinder to the design elevation at low speed and lock the lifting system after it is in place. Weld steel brackets to the bottom of the cylinder. The brackets are fully welded to the cylinder and the bottom rigid support. Then, weld the reinforcing rings symmetrically. After welding the brackets and reinforcing rings, perform non-destructive testing and stress testing. Dismantle the lifting system in the order of steel strand → jacks → pump station cluster → lifting load-bearing beam. When dismantling the steel strands, use a staged unloading method to complete the overall project.
2. The method according to claim 1, characterized in that, In S1, the lifting load-bearing beam of the hydraulic synchronous lifting system is fully welded to the platform reinforcement structure. The computer synchronous control system automatically stops and adjusts when the deviation exceeds the standard or the load is abnormal.
3. The method according to claim 1 or 2, characterized in that, The comprehensive inspection of the prefabricated standard sections in S2 includes comprehensive testing of dimensional accuracy, roundness, weld quality, and material properties. Anti-slip mats are laid on the surface of the steel transition platform at the bottom of the concrete outer cylinder.
4. The method according to claim 3, characterized in that, The S3 top section is connected to the steel strands of the lifting system via special anchors. The anchors of the temporary rigid support are firmly connected to the concrete outer cylinder, and the double-fixed structure is free from loosening and deformation.
5. The method according to claim 1 or 3, characterized in that, Before the three cylinders in S4 are lifted in tandem, it is confirmed that the lifting system has good synchronization and the steel strands are under uniform stress. The pairing accuracy of the hydraulic drive pairer is monitored in real time by a laser ranging device.
6. The method according to claim 5, characterized in that, In S4, welding operations utilize a liftable suspended construction platform, with dedicated personnel monitoring welding temperature and weld formation and adjusting welding process parameters promptly.
7. The method according to claim 1 or 6, characterized in that, The quality review of anti-corrosion and thermal insulation construction in S5 includes special tests on the thickness and adhesion of the anti-corrosion layer, as well as the thickness and fixing firmness of the thermal insulation layer.
8. The method according to claim 7, characterized in that, After the inner steel cylinder of S6 is placed, a dual fixing mode of bracket welding and reinforcing ring reinforcement is adopted. During the welding process, process measures are taken to reduce the impact of welding stress on the cylinder structure.