Massive concrete temperature control system with liftable rotary cooling pipe and temperature control method thereof

Abstract

The application discloses a large-volume concrete temperature control system with liftable and rotatable cooling pipes, which comprises an outer pipe, an outer pipe upper side pipe connected to the upper end of the outer pipe, an inner pipe coaxially arranged in the inner pipe upper side pipe, a water supply pool connected to the inner pipe through a water inlet pipe, a lifting driving mechanism connected to the outer pipe, a control system connected to the lifting driving mechanism, and a water return pipe through which the outer pipe upper side pipe passes through a water return pool. The application further discloses a control method of the large-volume concrete temperature control system with liftable and rotatable cooling pipes. The application solves the problems of rigid cooling area, difficult pipe pulling and non-recyclable materials in the existing large-volume concrete temperature control technology.

Description

Technical Field

[0001] This invention belongs to the field of building engineering temperature control technology, and relates to a temperature control system for large-volume concrete with liftable and rotatable cooling pipes. This invention also relates to a temperature control method for the temperature control system of large-volume concrete with liftable and rotatable cooling pipes. Background Technology

[0002] According to the "Standard for Construction of Mass Concrete" GB50496-2018, the minimum geometric dimension of mass concrete should not be less than 1 meter. During the pouring and curing process of mass concrete structures (such as bridge abutments, dams, and nuclear power plant foundations), the cement hydration reaction releases enormous amounts of heat. Due to the low thermal conductivity of concrete, internal heat is difficult to dissipate, while surface heat dissipation is faster, resulting in a significant temperature difference between the inside and outside of the structure. When the thermal tensile stress generated by this temperature difference exceeds the tensile strength of the concrete at the same age, through-cracks will occur, seriously threatening the safety and durability of the structure.

[0003] In existing technologies, the mainstream temperature control methods mainly include: pre-embedded cooling water pipe method: serpentine or coiled metal / plastic pipes are pre-embedded inside the concrete, and cold water is circulated to dissipate heat. However, this method results in a fixed position for the cooling pipes, which cannot cope with the phenomenon of "thermal center drift" during concrete pouring; moreover, the pipes are embedded in one go, resulting in resource waste and leaving heterogeneous defects inside the structure. Summary of the Invention

[0004] The purpose of this invention is to provide an intelligent temperature control system for large-volume concrete based on nested, liftable, and rotating cooling pipes, which solves the problems of rigid cooling zones, difficulty in removing pipes, and non-recyclable materials in existing large-volume concrete temperature control technologies.

[0005] Another objective of this invention is to provide a control method for a large-volume concrete temperature control system with a liftable and rotating cooling pipe.

[0006] The first technical solution adopted in this invention is a large-volume concrete temperature control system with a liftable and rotatable cooling pipe, including an outer pipe, an upper conduit connected to the upper end of the outer pipe, an inner pipe coaxially arranged inside the upper conduit of the outer pipe, the inner pipe connected to a water supply tank through an inlet pipe, a lifting drive mechanism connected to the outside of the outer pipe, the lifting drive mechanism connected to a control system, and the upper conduit of the outer pipe passing through a return water tank through a return water pipe.

[0007] The first technical solution of this invention is further characterized by: The upper end of the inner tube is connected to the water inlet pipe via a quick-connect fitting.

[0008] The outer tube is coaxially sleeved outside the inner tube, forming an annular cooling channel between the outer tube and the inner tube.

[0009] The lifting drive mechanism includes a motor, which is connected to a threaded rod via a flexible coupling. The threaded rod, acting as a worm, forms a worm gear reduction pair with the turbine. The turbine is coaxially connected to a drive gear, which is mounted on the inner ring of a ball bearing via a rotating shaft. The outer ring of the ball bearing is embedded in a bearing housing.

[0010] The bottom of the inner tube is equipped with a support device.

[0011] The outer wall of the outer tube is provided with a continuous helical external thread that meshes with the driving gear.

[0012] The upper conduit of the outer pipe extends vertically above the top of the outer pipe. One end of the upper conduit of the outer pipe is connected to the upper end of the outer pipe, and the other end of the upper conduit of the outer pipe is connected to the return water pipe through a quick connector. The return water pipe is connected to the return water tank.

[0013] The control system includes a control unit, which is connected to a motor, a servo motor, a concrete internal monitoring unit, a near-surface monitoring unit, a water flow monitoring sensor, and a wireless communication module.

[0014] The second technical solution adopted in this invention is a control method for a large-volume concrete temperature control system with a liftable and rotating cooling pipe, the specific steps of which are as follows: Step 1: The system is started and a cooling circuit is established; Step 2: Establish monitoring network initialization and baseline temperature; Step 3: Calculate the real-time temperature field and the temperature difference between inside and outside; Step 4: Temperature Anomaly Judgment and Early Warning Control; Step 5: Determine the location of the thermal center and the target elevation; Step 6: Adjust the height of the outer tube using the lifting drive mechanism to achieve overlap and coverage between the cooling section and the high-temperature zone; Step 7: Check the temperature tensile stress of the concrete and implement graded cooling protection based on the check results; Step 8: Determine the completion of concrete curing and shut down the system.

[0015] The second technical solution of the present invention is further characterized by: The specific process of step 1 is as follows: After the concrete is poured, the control unit issues a pump start command, and the adjustable water pump draws cooling water from the water supply tank, which is sent into the inner pipe through the inlet pipe and quick connector. The cooling water flows from top to bottom through the bottom of the inner pipe and then enters the annular cooling channel between the inner and outer pipes. It flows from bottom to top, and after absorbing the heat of hydration of the concrete, it flows into the upper guide tube of the outer pipe through the top of the outer pipe, and then returns to the return water tank through the return water pipe in sequence, forming a closed cooling loop with inner inlet and outer outlet and annular heat exchange. The specific process of step 2 is as follows: The concrete internal monitoring unit is pre-embedded at different elevations and cross-sections, and the near-surface monitoring unit is arranged 30-50 mm away from the outer surface of the component. The water flow monitoring sensor is installed on the inlet pipe, return pipe and the upper conduit of the outer pipe. After the system is running normally, the concrete internal monitoring unit and the near-surface monitoring unit collect the concrete internal temperature and near-surface temperature at a preset sampling period. The water flow monitoring sensor collects the cooling water flow rate and water temperature simultaneously. All data is uploaded to the control unit through the wireless communication module to establish the baseline of the initial temperature field distribution and the internal and external temperature difference ΔT. The specific process of step 3 is as follows: During the heat release process of concrete hydration, the control unit continuously receives data from the internal monitoring unit and the near-surface monitoring unit, performs paired calculations on the internal and near-surface temperatures at the same elevation, and calculates the internal and external temperature difference ΔT = T in real time. 内 T 表 And identify the current highest temperature point and the elevation range where the maximum ΔT is located; The specific process of step 4 is as follows: When the internal and external temperature difference ΔT at any monitoring elevation reaches the warning threshold, the control unit determines that there is an abnormal temperature trend in the area and enters the warning-level control mode. In this mode, the control unit increases the operating frequency of the adjustable water pump based on the real-time data of the water flow monitoring sensor. The specific process of step 5 is as follows: When the internal and external temperature difference ΔT continues to increase and reaches the intervention level threshold, the control unit determines the elevation range of the internal thermal center of the concrete based on the temperature distribution of the internal monitoring units at different elevations. The control unit converts the thermal center elevation into the axial displacement required by the outer pipe and generates the corresponding target lifting position parameters as the control command to drive the subsequent action of the support lifting device. The specific process of step 6 is as follows: The control unit sends start / stop and speed commands to the servo motor in the support lifting device. The servo motor drives the threaded rod to rotate via the flexible coupling, which in turn drives the turbine to rotate. The drive gear, which is coaxially connected to the turbine, rotates accordingly. The drive gear meshes with the continuous helical external thread on the outer wall of the outer tube, and the outer tube moves up and down in the vertical direction. After the outer tube completes the lifting and stabilizes at the elevation of the thermal center, the control unit locks the position of the servo motor and applies a frequency command to the adjustable water pump, so that the cooling water circulates in the annular channel formed by the inner and outer tubes. The specific process of step 7 is as follows: Based on real-time temperature data from the internal monitoring unit and the near-surface monitoring unit, the control unit calculates the tensile stress at the corresponding temperature and compares it with the design value of the concrete tensile strength. When the calculated stress approaches the preset safety threshold, the system automatically enters the graded cooling protection mode: gradually reducing the operating frequency of the adjustable water pump and the cooling water circulation flow rate. The specific process of step 8 is as follows: When the control unit determines that the highest internal temperature of the concrete is close to the ambient temperature, the internal and external temperature difference ΔT at each monitoring elevation meets the relevant specifications and design requirements, and the concrete has reached the predetermined curing time, it outputs a shutdown command to stop the cooling water circulation loop.

[0016] The beneficial effects of this invention are as follows: 1. Automatic lifting and dynamic targeted cooling: The system uses a servo motor to drive a worm gear mechanism to automatically lift and lower the outer tube, ensuring that the cooling water always flows through the area with the highest temperature. This greatly improves heat exchange efficiency, effectively reduces peak and valley temperatures, and lowers the risk of temperature cracks.

[0017] 2. Simplified structure and high reliability: The outer tube's own thread is used as the transmission component, eliminating the need for additional push rods or hydraulic cylinders. The structure is compact, and the thread on the outer wall of the outer tube can also play a certain "scraping" role during the lifting process. Combined with the anti-stick coating, it can prevent the tube from being stuck by concrete.

[0018] 3. Flexible layout and strong adaptability: The cooling pipe assembly consists of inner and outer nested pipes, with the support fixed inside the template. The inlet and outlet water pipes can flexibly bypass obstacles through standard pipe fittings such as tees and elbows, adapting to large-volume concrete structures with different cross-sectional shapes (rectangular, round-ended, etc.) and sizes, and the layout scheme is flexible and diverse.

[0019] 4. Green construction and reusable: The inner and outer pipes are designed as pull-out structures. After curing, the pipes can be recycled by rotating or directly pulling them out, reducing project costs and leaving no foreign matter inside the concrete. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the large-volume concrete temperature control system with liftable and rotating cooling pipes of the present invention. Figure 2 This is a partial enlarged view of the cooling pipe assembly in the large-volume concrete temperature control system of the present invention, which features a liftable and rotating cooling pipe. Figure 3 This is a schematic diagram of the outer pipe thread and gear drive structure in the large-volume concrete temperature control system of the liftable and rotating cooling pipe of the present invention. Figure 4 This is a schematic diagram of the guide and limit mechanism in the large-volume concrete temperature control system of the liftable and rotating cooling pipe of the present invention. Figure 5 This is a schematic diagram of the contact between the ball screw pair and the outer tube in the large-volume concrete temperature control system of the liftable and rotating cooling pipe of the present invention. Figure 6 This is a diagram showing the longitudinal arrangement of sensors in the large-volume concrete temperature control system with a liftable and rotating cooling pipe according to the present invention. Figure 7 This is a diagram showing the arrangement of sensors on the cross-section of a concrete bridge pier in the large-volume concrete temperature control system with a liftable and rotating cooling pipe according to the present invention.

[0021] In the diagram, 1. Upper guide tube of outer pipe, 2. Inner pipe, 3. Outer pipe, 4. Support, 5. Support lifting device, 6. Limiting device, 7. Guide rail, 8. Threaded rod, 9. Servo motor, 10. Turbine, 11. Support platform, 12. Nut, 13. Screw, 14. Ball screw nut, 15. Ball, 16. Waterproof plug, 17. Quick connector, 18. Inlet pipe, 19. Ball bearing, 20. Bearing housing, 21. Drive gear, 22. Flexible coupling, 23. Motor, 24. Return pipe, 25. Water storage tank, 26. Return water tank, 27. Cooling tank, 28. Water flow monitoring sensor, 29. Adjustable water pump, 30. Water supply tank, 31. Support device, 32. Concrete internal monitoring unit, 33. Near-surface monitoring unit, 34. Wireless communication module, 35. Control unit, 36. Water pressure sensor, 37. Annular channel between inner / outer pipes. Detailed Implementation

[0022] The following detailed description is provided in conjunction with specific implementation methods.

[0023] This invention is based on an intelligent temperature control system for large-volume concrete with nested, liftable, and rotating cooling pipes, aiming to achieve dynamic, precise, and intelligent control of the heat of hydration in large-volume concrete.

[0024] Example 1 The cooling pipe assembly of this invention adopts an innovative structure of inner and outer nesting, dynamic and static separation, and adjustable water return, effectively solving the technical problems of traditional cooling pipes such as easy clogging in large-volume concrete, fixed cooling area, and inability to dynamically control. Figure 1 As shown, the cooling pipe assembly includes an inner pipe 2, an outer pipe 3, and an upper guide pipe 1 on the outer pipe. The three work together to form a closed-loop cooling path of "inner inlet and outer outlet, annular flow, and dynamic return".

[0025] Example 2 like Figure 2As shown, the inner pipe 2 is made of PE-RT (heat-resistant polyethylene) or 304 stainless steel, with an outer diameter of 50 mm, a wall thickness of 3 mm, and a length customized according to the pier height (usually 10–30 m). The inner pipe 2 is vertically installed inside the concrete, serving as a cooling water inlet pipe. The upper end of the inner pipe 2 is connected to the inlet pipe 18 via a quick-connect fitting 17, while the lower end is either closed or equipped with a diffuser nozzle. It remains stationary throughout the concrete pouring and curing process. The upper and middle parts of the inner pipe 2 are fixed to the support 4 via a support platform 11. The support platform 11 is a rectangular plate structure with openings. The inner pipe 2 passes through the openings and is securely connected using a conventional pipe clamp structure similar to that used for building drainage pipes (this connection method is existing technology), ensuring that the inner pipe 2 does not shift or deform during construction.

[0026] The inner pipe 2 is installed before the concrete is poured and is fixed by the U-shaped clamps on the support platform 11 to ensure that it remains stationary throughout the curing period.

[0027] Example 3 The outer tube 3 is coaxially sleeved outside the inner tube 2, forming an annular cooling channel between them. The outer tube 3 is a liftable cooling section with a smooth inner wall to reduce water flow resistance. The outer wall of the outer tube 3 has a continuous spiral external thread for meshing with the drive gear 21 to achieve axial lifting. The middle part of the outer tube 3 passes through another opening in the support platform 11. The inner ring of the ball screw nut 14 forms a rolling fit with the outer tube 3 through multiple balls 15, and its outer ring is fixedly connected to the bottom of the support platform 11 by the screw 13 and nut 12. With the help of the rolling of the balls 15, the outer tube 3 can move vertically up and down. Furthermore, the outer surface of the outer tube 3 is coated with a polytetrafluoroethylene (PTFE) coating, which significantly reduces the coefficient of friction and adhesion between it and the concrete, ensuring that the structure will not jam or crack due to the initial setting of the concrete when the outer tube 3 is raised or lowered.

[0028] Example 4 The upper conduit 1 of the outer pipe extends above the top of the outer pipe 3. One end of the upper conduit 1 of the outer pipe is connected to the upper end of the outer pipe 3, and the other end of the upper conduit 1 of the outer pipe is connected to the return water pipe 24 through the quick connector 17, and then leads to the return water pool 26, forming a complete return water path.

[0029] The connector of the upper conduit 1 of the outer pipe is provided with an external thread, which can be screwed into the corresponding internal thread on the support platform 11 for mechanical fixation. A waterproof plug 16 and a water pressure sensor 32 are installed near the connector of the upper conduit 1 of the outer pipe to monitor the sealing status and internal water pressure at the interface, preventing grout from seeping into the pipe during concrete pouring. Similarly, the connection between the return pipe 24 and the upper conduit 1 of the outer pipe is also provided with a quick connector 17, a waterproof plug 16, and a water pressure sensor 32. The quick connector 17 adopts a flange connection, which facilitates quick installation and disassembly on site and ensures reliable sealing.

[0030] The support frame 4 is a steel structure bearing frame welded together. It is preferably made of Q235 or equivalent structural steel plates and sections. The frame is arranged symmetrically on both sides and is fixedly installed on the pier construction formwork. It is used to provide rigid support and installation base for the cooling pipe assembly and its lifting drive mechanism.

[0031] The inlet pipe 18 and the return pipe 24 are composed of multiple pipe sections spliced ​​together. The splicing points are connected with standard pipe fittings such as tees and elbows, which allows the pipeline to flexibly bypass the support 4 and other obstacles, adapting to complex construction site layouts.

[0032] During operation, cooling water is pressurized from the water supply tank 30 by the adjustable water pump 29, and then enters the stationary inner pipe 2 through the inlet pipe 18 and quick connector 17. It then flows into the annular channel between the inner pipe 2 and the outer pipe 3, absorbs the heat of concrete hydration, and flows from the top of the outer pipe 3 into the upper guide pipe 1, before returning to the return water tank 26 via the return water pipe 24, completing one cooling cycle. When the data collected by the concrete internal monitoring unit 32 and the near-surface monitoring unit 33 is uploaded to the control unit 35 via the wireless communication module 34, the control unit 35 calculates the internal and external temperature difference ΔT at the same elevation in real time. When ΔT ≥ 25℃ (intervention threshold), the control unit 35 determines that there is a temperature anomaly in that depth area and immediately outputs a control command. The drive motor 23 drives the drive gear 21 to rotate. The drive gear 21 meshes with the threaded outer wall of the outer pipe 3, driving the outer pipe 3 to rise and fall to the elevation corresponding to the high-temperature area, ensuring that the high-temperature area is always within the effective coverage of the annular cooling channel, achieving dynamic and precise control of the cooling position.

[0033] The cooling water flow path is as follows: water supply tank 30 → adjustable water pump 29 → inlet pipe 18 → inner pipe 2 → annular channel 37 between inner and outer pipes → top of outer pipe 3 → upper conduit 1 of outer pipe (after the flowing water enters the inner pipe 2 through the inlet pipe 18, it smoothly enters the upper conduit 1 of the outer pipe and the outer pipe 3. The outer pipe 3 is driven to move up and down in the concrete by the drive gear 21, so as to realize the movement of cooling water in the concrete and thus achieve local cooling) → return pipe 24 → return water tank 26, forming a closed loop of "inner inlet and outer outlet, annular heat exchange".

[0034] Example 5 The control system of this invention adopts a technical architecture of multi-source heterogeneous sensor network + edge intelligent decision-making + closed-loop dynamic control to achieve high-precision perception, real-time analysis and active intervention of temperature field and stress field of large-volume concrete, effectively preventing the generation of temperature cracks.

[0035] The control system includes a sensor network, a wireless communication module 34, and a control unit 35. The control unit 35 uses a Siemens S7-1200 PLC controller and is equipped with a 7-inch touch screen human-machine interface.

[0036] The sensor network consists of the following three types of units: Concrete internal monitoring unit 32: Utilizing a composite encapsulation of vibrating wire strain gauges and PT100 platinum resistance thermometers, the PT100 platinum resistance thermometers monitor temperature. These units are arranged along the pier height at key locations: 0.5 m from the pier bottom, 1 / 3 of the pier height, 1 / 2 of the pier height, and 1.0 m from the pier top, with a vertical spacing of no more than 1.2 m. In the plane, they are symmetrically arranged in four quadrants according to a rectangular cross-section or a rounded cross-section, with no fewer than two measuring points per layer, also symmetrically arranged. All internal monitoring units are embedded within the concrete at a distance of no less than 100 mm from the outer surface and rigidly fixed by dedicated reinforcing bars, maintaining a minimum clear distance of 50 mm from the vertical main reinforcement bars to avoid structural stress interference and temperature conduction distortion, ensuring the authenticity and representativeness of the monitoring data.

[0037] Near-surface monitoring unit 33: Employs a WZP-P type patch-type PT100 platinum resistance temperature sensor (or equivalent), with a temperature measurement range of -50℃ to +200℃ and accuracy class A. It is positioned at a depth of 30 mm to 50 mm from the outer surface of the concrete (not exposed), and encased in a flexible protective sleeve (such as silicone rubber or polyurethane). This unit monitors the true surface temperature, which is minimally affected by instantaneous disturbances such as wind and sunlight. It is paired with the concrete interior monitoring unit 32 at the same elevation to calculate the internal and external temperature difference (ΔT) in real time, providing crucial information for crack risk assessment.

[0038] The water flow monitoring sensor 28 is a combination of an external clamp-on ultrasonic flow meter and a PT100 platinum resistance temperature sensor (e.g., FLEXIM FLUXUS F721 or equivalent). The sensor is non-invasively installed on the inlet pipe 18, return pipe 24, and the upper conduit 1 of the outer pipe. It provides flow measurement accuracy of ±0.5%, supports bidirectional flow detection, and features an anti-clogging structure. It is used for real-time monitoring of cooling water velocity, flow rate, and temperature. The sensor has a compressive strength greater than 5 MPa, ensuring accurate acquisition of hydraulic parameters and normal operation even under complex hydraulic conditions, providing data support for cooling performance evaluation and pump control.

[0039] All data collected by the sensors is uploaded to the control unit 35 in real time via the wireless communication module 34. The wireless transmission protocol of the wireless communication module 34 can be flexibly configured according to the communication conditions at the engineering site, achieving low-power and highly reliable data transmission.

[0040] As the core of the system, the control unit 35 receives and integrates multi-source data from the concrete interior monitoring unit 32, the near-surface monitoring unit 33, and the water flow monitoring sensor 28, and calculates the following key indicators in real time: The highest internal temperature of concrete; the temperature difference between the inside and outside at the same elevation (ΔT = T) 内部 T表层 ); The temperature tensile stress value caused by temperature deformation (calculated based on the concrete elastic modulus, creep, and constraint condition model). When the monitoring data meets any of the following preset conditions, the control unit 35 automatically triggers the graded control strategy: Warning level: When ΔT ≥ 22℃: issue a warning, start low-flow cooling (water pump frequency 30 Hz) to maintain basic heat dissipation; Intervention level: When ΔT ≥ 25℃: The automatic control servo motor 9 raises and lowers the outer tube 3 to the high temperature area and increases the water pump frequency to 50 Hz to enhance local cooling. The control unit 35 automatically controls the drive motor 23 to operate and accurately raises and lowers the outer tube 3 to the corresponding elevation of the high temperature area through the bracket lifting device 5. At the same time, the adjustable water pump 29 is adjusted to increase the cooling water flow and implement fixed-point enhanced cooling. Emergency Level: When the calculated temperature tensile stress value approaches 70% of the design value of concrete tensile strength, the system starts a graded cooling program, that is, gradually reducing the cooling intensity and controlling the cooling rate (≤2℃ / d) to avoid secondary temperature cracks caused by excessively rapid cooling.

[0041] In addition, all monitoring data and control records are uploaded to the remote monitoring platform through the wireless communication module 34, supporting cloud storage, visualization and historical backtracking, realizing digital and intelligent management of the entire process of temperature control for large-volume concrete.

[0042] The water system provides controllable, circulating cooling water to the interior of the bridge pier concrete, enabling active regulation of the hydration heat temperature rise and ensuring that the internal and external temperature difference and cooling rate meet the requirements of the "Standard for Construction of Mass Concrete" (GB 50496-2018). This system specifically includes: The water supply tank 30 is used to store the cooled water after cooling treatment, serving as the main cooling water source; the adjustable water pump 29 pressurizes the cooling water and delivers it to the inner pipe 2 through the water inlet pipe 18 to form a cooling circuit.

[0043] The return water tank 26 is used to collect the high-temperature return water flowing out from the upper conduit 1 of the outer pipe. The return water is at a high temperature and needs to be cooled before it can be recycled in order to avoid the accumulation of heat in the system and the resulting decrease in cooling efficiency.

[0044] The water storage tank 25 serves as a backup cooling water source, storing pre-cooled low-temperature water. It is activated in emergency situations such as failure of the main water supply system, excessively high return water temperature, or a rapid increase in the internal temperature of the bridge pier, ensuring uninterrupted cooling and improving system reliability and emergency response capabilities.

[0045] Cooling pool 27 is located between return water pool 26 and supply water pool 30 to cool the high-temperature return water. Cooling pool 27 can adopt natural heat dissipation, forced air cooling or mechanical refrigeration. Preferably, a simple forced air cooling structure with an industrial fan and spray device installed above the return water pool is adopted. By enhancing air convection and evaporative heat dissipation, the temperature of the return water is effectively reduced to near the ambient wet-bulb temperature to meet the circulating cooling requirements.

[0046] The adjustable water pump 29 is installed outside the water supply tank 30 and is driven by a variable frequency drive. It can dynamically adjust the water supply pressure and flow rate according to the cooling demand, so as to achieve energy saving and precise temperature control.

[0047] Water inlet pipe 18 and water return pipe 24: Water inlet pipe 18 connects the outlet of adjustable water pump 29 and the inlet of inner pipe 2, and is used to transport cooling water to the inside of the bridge pier; Water return pipe 24 connects the outlet of upper conduit 1 of outer pipe and the inlet of return pool 26, and is used to recover high-temperature return water.

[0048] Water flow monitoring sensor 28: Installed on the inlet pipe 18 and / or return pipe 24, it is used to monitor the flow rate, flow rate and water temperature of cooling water in real time, and to provide hydraulic parameters for control.

[0049] The quick-connector 17 is located at the connection between the inlet pipe 18 and the inner pipe 2, and the return pipe 24 and the upper conduit 1 of the outer pipe, to facilitate the installation, disassembly and maintenance of the cooling pipe assembly, while ensuring a tight seal.

[0050] Waterproof plug 16 is installed at the opening where the cooling pipe passes through the concrete formwork to prevent cement slurry from seeping into the pipe during the pouring process and to ensure unobstructed pipeline flow.

[0051] like Figure 3 As shown, the support lifting device 5 is installed on the upper part of the support 4 and mainly consists of two parts: a drive device and a guiding synchronization mechanism. The drive device comprises a motor 23, a servo motor 9, a flexible coupling 22, a threaded rod 8, a worm gear 10, a drive gear 21, a ball bearing 19, and a bearing housing 20. The motor 23 is connected to the threaded rod 8 via the flexible coupling 22. The threaded rod 8, acting as a worm, forms a worm gear reduction pair with the worm gear 10. The worm gear 10 is coaxially and fixedly connected to the drive gear 21. The drive gear 21 is mounted on the inner ring of the ball bearing 19 via a rotating shaft. The outer ring of the ball bearing 19 is embedded in the bearing housing 20, which is rigidly fixed to the support 4, thus providing high-rigidity, low-friction rotational support for the drive gear 21. During operation, the motor 23 starts and drives the threaded rod 8 to rotate via the flexible coupling 22, which in turn drives the turbine 10 and the drive gear 21 to rotate synchronously. Since the drive gear 21 is precisely engaged with the continuous spiral external thread on the outer wall of the outer tube 3, and the outer tube 3 is constrained by the limiting device and cannot rotate, the outer tube 3 is forced to rise and fall along the axial direction, thereby realizing the dynamic adjustment of the cooling area.

[0052] Example 6 like Figure 4 , 5 As shown, the guiding synchronization mechanism includes a guide rail 7, a limiting device 6, a screw 13, a ball screw nut 14, and balls 15. The screw 13 is vertically fixed to the bracket 4, and its surface is provided with precision ball screw threads. The ball screw nut 14 is an integral rotating component; its inner ring rolls with the screw 13 through the balls 15, and its outer ring is rigidly connected to the bracket platform 11. When the drive gear 21 drives the outer tube 3 to rise and fall, the ball screw nut 14 rotates synchronously through mechanical linkage (such as a synchronous drive shaft or a shared drive source). Since the screw 13 is fixed, the ball screw nut 14 converts the rotational motion into linear motion, driving the bracket platform 11 to rise and fall synchronously along the guide rail 7. Meanwhile, the limiting device 6 is a U-shaped steel clamp with a hole on the lower side. The limiting device 6 is detachably fixed to the side wall of the support platform 11 through the hole by at least two sets of standard bolt pairs. The limiting device 6 cooperates with the guide rail 7 to limit the lateral swing and circumferential rotation of the outer tube 3 and the support platform 11, ensuring that the entire lifting process is smooth and without shaking, and ensuring the positional accuracy of the sensors (such as the concrete internal monitoring unit 32 and the near-surface monitoring unit 33) and the connection reliability of the quick connector 17.

[0053] Thin-walled 304 stainless steel tubing (80 mm outer diameter, 2 mm wall thickness) is used, with continuous helical external threads (10 mm pitch, 60° thread angle) machined on its outer wall for meshing with the drive gear 21. The outer tube 3 is a liftable cooling section, with its inner wall polished to reduce water flow resistance. The outer surface of the outer tube 3 is coated with a 30 μm thick polytetrafluoroethylene (PTFE) coating, formed by a spraying + 280℃ high-temperature sintering process to create a dense and smooth film, effectively preventing the concrete from adhering to the outer tube during the initial setting stage and ensuring smooth lifting.

[0054] The upper conduit 1 of the outer tube is made of pressure-resistant flexible hose (such as stainless steel braided hose), and its length is not less than 1.25 times the maximum lifting stroke of the outer tube 3 (for example, if the maximum lifting height is 2 m, then the conduit length is ≥2.5 m) to accommodate the displacement changes during the lifting process of the outer tube. The conduit joint is provided with external threads, which can be screwed into the opening with internal threads on the support platform 11 for mechanical fixation. A waterproof plug (16) and a water pressure sensor are installed near the interface to monitor the sealing status and internal pressure.

[0055] The support frame and lifting drive device include support frame 4, support frame lifting device 5, and guide limit mechanism 6.

[0056] The support frame 4 is welded from symmetrically arranged Q235 steel plates and fixed to the inside of the pier construction formwork. A support platform 11 is located on the upper part of the support frame 4. The platform is a rectangular steel plate with multiple openings, through which the inner tube 2 and outer tube 3 pass. Anti-tipping counterweights (with a single-sided weight ≥ 50 kg) are welded to the outer bottom of the support frame 4 to enhance overall stability.

[0057] The support lifting device 5 is installed on the upper part of the support 4 and includes a servo motor 9 (rated power 500 W), a flexible coupling 22, a threaded rod 8 (i.e., a worm gear), a turbine 10, a drive gear 21, ball bearings 19, and a bearing housing 20. The servo motor 9 is connected to the threaded rod 8 via the flexible coupling 22. The threaded rod 8 and the turbine 10 form a worm gear reduction pair (reduction ratio 1:10). The turbine 10 is coaxially connected to the drive gear 21 (60 teeth, module 2, tooth surface hardness HRC58 or higher). The drive gear 21 is mounted on the inner ring of a pair of angular contact ball bearings 19 via a rotating shaft. The outer ring of the bearings is embedded in the bearing housing 20, which is rigidly fixed to the support 4. The drive gear 21 precisely meshes with the external thread of the outer tube 3.

[0058] The guide and limit mechanism 6 includes a guide rail 7 and a slider, as well as a ball screw pair (screw 13, ball screw nut 14, and balls 15). The screw 13 is vertically fixed to the bracket 4; the ball screw nut 14 is rigidly connected to the bracket platform 11, and its inner ring makes rolling contact with the screw 13 through the balls 15. When the outer tube 3 is raised or lowered, the ball screw nut 14 is rotated through synchronous transmission, driving the bracket platform 11 to rise and fall synchronously, ensuring a stable connection between the sensor and the pipeline. The ball screw has a precision grade of C5, and its movement is smooth and without wobbling.

[0059] During operation, the servo motor 9 starts and drives the drive gear 21 to rotate after being reduced by a worm gear. Since the outer tube 3 is constrained by the guide limit mechanism and cannot rotate, the outer tube 3 moves smoothly up and down along the axial direction under the meshing action of the gear and thread, with a stroke of 0-2.5 m and a positioning accuracy of ±1 mm.

[0060] like Figure 6 , 7 As shown, the intelligent sensing and control system includes: a concrete internal monitoring unit 32, a near-surface monitoring unit 33, a water flow monitoring sensor 28, a wireless communication module 34, and a control unit 35.

[0061] Concrete internal monitoring unit 32: Employing a vibrating wire strain gauge integrated with a PT100 platinum resistance thermometer, it is deployed along the pier height at points 0.5 m from the pier bottom, 1 / 3H, 1 / 2H, and 1.0 m from the pier top, with a vertical spacing ≤1.2 m; symmetrically arranged in four quadrants, with ≥2 measuring points per layer. The sensor is embedded at a depth ≥100 mm and fixed by reinforcing bars, at a distance ≥50 mm from the main reinforcement.

[0062] Near-surface monitoring unit 33: Located at a depth of 30–50 mm from the concrete surface, encased in a flexible silicone rubber protective sleeve, and paired with an internal unit at the same elevation, used to calculate the temperature difference between the inside and outside.

[0063] Water flow monitoring sensor 28: Installed on the inlet pipe 18, return pipe 24 and upper conduit 1 of the outer pipe, it adopts a combination of electromagnetic flow meter (accuracy ±0.5%) and PT100 temperature sensor, and has pressure resistance ≥1.0 MPa, anti-clogging structure and anti-bubble algorithm.

[0064] The wireless communication module 34 adopts an industrial-grade 5G / NB-IoT dual-mode communication module to upload sensor data to the control unit 35 and the remote cloud platform in real time.

[0065] The control unit 35 uses a Siemens S7-1200 PLC controller and is equipped with a 7-inch touchscreen human-machine interface. The system calculates in real time: the highest internal temperature of the concrete; and the temperature difference between the inside and outside at the same elevation (ΔT = T). 内 T 表 Temperature tensile stress (based on concrete elastic modulus and constraint model).

[0066] When the stress is ≥ 0.7f tk (Design value of concrete tensile strength): Start the graded cooling program and control the cooling rate to ≤ 2℃ / d.

[0067] The water system includes: a water supply tank 30, a return water tank 26, a cooling tank 27, and a water storage tank 25.

[0068] Water supply tank 30: volume 50 m³, equipped with two adjustable water pumps 29 (single flow rate 50 m³ / h, head 30 m). Return water tank 26: 60 m³ volume, for collecting returned water; Cooling pool 27: A closed cooling tower is used to cool the return water to ≤20℃ before returning it to the water supply pool 30; Water storage tank 25: with a volume of 30 m³, is used as an emergency backup. Pipeline connection: The inlet pipe 18 and the return pipe 24 are spliced ​​from multiple sections of PE pipe, and bypass the support 4 through tees and elbows. The interface adopts quick connector 17.

[0069] The system installation and operation process is as follows: Installation steps: Install bracket 4 inside the template and add assembly weights; pass inner tube 2 through the hole in bracket platform 11, fix it with U-shaped clamps, and connect the upper end to water inlet pipe 18; sleeve outer tube 3 outside inner tube 2, and connect the top of outer tube upper conduit 1; install bracket lifting device 5, and adjust the drive gear 21 to fully mesh with the outer tube thread; deploy sensor network and connect wireless communication module 34; connect water system and conduct sealing and water flow tests.

[0070] Operation process: After concrete pouring, the system starts automatically, and the sensor collects data once per minute; the control unit 35 analyzes the data to determine whether the cooling position needs to be adjusted; if intervention is required, the servo motor 9 drives the outer pipe 3 to rise and fall to the target elevation; temperature and stress are continuously monitored, and cooling parameters are dynamically optimized; after the curing period, the control unit 35 determines that the internal temperature of the concrete and the temperature difference between the inside and outside meet the design and specification requirements, and then closes the adjustable water pump 29 and related valves to stop the cooling circuit from running. Then, the connection between the inlet pipe 18 and the return pipe 24 and the cooling pipe assembly is disconnected through the quick connector 17. If necessary, the cooling water in the pipeline is appropriately discharged or diverted; then, the fixed connection between the support 4 and the formwork is released, and the inner pipe 2, outer pipe 3 and support device 31 are pulled out of the concrete structure as a whole using the support lifting device 5 or external lifting equipment, so as to realize the recycling and reuse of the cooling pipe assembly.

[0071] The temperature control method of the large-volume concrete temperature control system with liftable and rotating cooling pipe of the present invention is as follows: Step 1, System startup and cooling loop establishment: After the concrete is poured, the power supply to the control unit 35, adjustable water pump 29, motor 23, servo motor 9, and wireless communication module 34 is turned on to complete the system self-test and communication debugging. The control unit 35 issues a pump start command, and the adjustable water pump 29 draws cooling water from the water supply tank 30, which is then sent into the inner pipe 2 through the inlet pipe 18 and quick connector 17. The cooling water flows from top to bottom through the bottom of the inner pipe 2 and then enters the annular cooling channel between the inner pipe 2 and the outer pipe 3. It flows from bottom to top, and after absorbing the heat of hydration of the concrete, it flows into the upper guide tube 1 of the outer pipe through the top of the outer pipe 3, and then returns to the return water tank 26 through the return water pipe 24, forming a closed cooling loop of "inner inlet and outer outlet, annular heat exchange".

[0072] Step 2, Monitoring network initialization and baseline temperature establishment: The internal concrete monitoring unit 32 is pre-embedded at different elevations and cross-sectional locations, while the near-surface monitoring unit 33 is arranged 30–50 mm from the outer surface of the component. The water flow monitoring sensor 28 is installed on the inlet pipe 18, the return pipe 24, and the upper conduit 1 of the outer pipe. After the system is in normal operation, the internal monitoring unit 32 and the near-surface monitoring unit 33 collect the internal and near-surface temperatures of the concrete at a preset sampling period. The water flow monitoring sensor 28 simultaneously collects the cooling water flow rate and water temperature. All data is uploaded to the control unit 35 via the wireless communication module 34 to establish the initial temperature field distribution and the baseline of the internal and external temperature difference ΔT.

[0073] Step 3, Real-time temperature field and internal / external temperature difference calculation: During the heat release process of concrete hydration, the control unit 35 continuously receives data from the concrete internal monitoring unit 32 and the near-surface monitoring unit 33, performs paired calculations on the internal temperature and near-surface temperature at the same elevation, and calculates the internal and external temperature difference ΔT = T in real time. 内 T 表 It identifies the current highest temperature point and the elevation range where the maximum ΔT occurs. Simultaneously, it evaluates the heat exchange effect of the current cooling circuit by combining the instantaneous flow rate and inlet / outlet water temperature feedback from the water flow monitoring sensor 28.

[0074] The specific process for evaluating the heat exchange effect is as follows: The control unit 35 first uses the real-time flow rate q and inlet / outlet water temperature T fed back by the water flow monitoring sensor 28. 进、 T 出 Calculate the actual heat exchange power Q of the current cooling circuit using the following formula. 实 : Q 实 =ρ c p q (T 出 T 进 ) in: ρ: The density of cooling water (kg / m³) is approximately 1000 kg / m³. c p The specific heat capacity of the cooling water (J / kg·℃) is approximately 4200 J / kg·℃. q: Circulating flow rate (m³ / h) is the core variable for pump frequency control. Simultaneously calculate the heat transfer efficiency coefficient. :

[0075] In the formula T 内，max The internal monitoring temperature is the highest temperature point currently observed. Control unit 35, based on... Value and The heat exchange effect level is determined by a comprehensive assessment of the changing trend: when and When the temperature continues to drop, the heat exchange effect is considered good, and the current pump frequency should be maintained; when Furthermore, if the real-time flow rate is lower than the design flow rate, it is determined to be insufficient flow, and the pump operating frequency is automatically increased; when When the flow rate has reached the design value, it is determined that the cooling pipe position is deviated from the thermal center, triggering the external pipe lifting and repositioning process; when the temperature difference between the inlet and outlet water is less than 1℃, it is determined that the heat exchange has failed, and the control unit 35 issues a fault warning and prompts manual inspection.

[0076] Step 4, Temperature Anomaly Judgment and Early Warning Control: When the internal and external temperature difference ΔT at any monitoring elevation reaches the warning threshold (e.g., ΔT ≥ 22 ℃), the control unit 35 determines that there is an abnormal temperature trend in the area and enters the warning-level control mode. In this mode, the control unit 35 automatically increases the operating frequency of the adjustable water pump 29 based on the real-time data from the water flow monitoring sensor 28 to achieve the optimal circulation flow rate, effectively enhancing the overall heat dissipation capacity, while maintaining the external pipe 3 at the current height to provide basic cooling for the area.

[0077] The operating frequency of the water pump is gradually increased according to a preset step size. When one of the two stopping conditions is met, the control unit 35 stops increasing the frequency and triggers the corresponding subsequent processing logic: Condition 1 (Temperature Difference Decline): Frequency increase will stop when the internal and external temperature difference falls below the warning threshold and meets the hysteresis condition. The determination formula is as follows:

[0078] In the formula: ΔT is the warning level threshold (°C), which is 22°C in this embodiment; δ is the hysteresis, which is recommended to be 2°C to prevent frequent start-stop.

[0079] Condition 2 (Flow rate reaches the upper limit): When the circulating flow rate Q reaches the rated maximum flow rate Q max Stop frequency increase when it reaches 90%, the determination formula is:

[0080] Where: Q is the real-time circulating flow rate (m³ / h) detected by the water flow monitoring sensor 28; Q max This is the rated maximum flow rate (m³ / h) of the adjustable water pump 29. This condition is the upper limit for pump protection to prevent overload damage to the equipment.

[0081] Step 5: Locating the thermal center and determining the target elevation: When the internal and external temperature difference ΔT continues to increase and reaches the intervention threshold (e.g., ΔT ≥ 25 ℃), or the temperature tensile stress calculated from the temperature field... When the concrete tensile strength is close to 70%-80% of the design value, the control unit 35 determines the elevation range of the internal thermal center of the concrete based on the temperature distribution of the internal monitoring unit 32 at different elevations.

[0082] Step 1: Calculate the elevation point of the thermal center. The control unit 35 reads the real-time temperature value T from all n internal monitoring units 32 arranged along the pouring height direction. i and its corresponding elevation z i (i=1,2,…,n), using the temperature value of each monitoring point as a weight, the weighted average elevation z of the thermal center is calculated according to the following formula:

[0083] In the formula: z 热中心 The weighted average elevation (m) of the thermal center; z i T represents the elevation (m) of the i-th monitoring unit. i Let be the real-time temperature (°C) of the i-th monitoring unit; n is the total number of internal monitoring units.

[0084] Step 2: Determine the initial thermal center elevation range. Using the thermal center z as the center and considering the effective cooling coverage length L of outer pipe 3, determine the range radius r. The calculation formula is:

[0085] In this embodiment, the effective cooling coverage length L of the outer pipe 3 is 2.0 m, corresponding to a radius r = 1.0 m. The elevation interval of the thermal center is [z 热中心 -r, z 热中心 +r).

[0086] The elevation range obtained after the above two steps of screening is the final thermal center elevation range.

[0087] Temperature tensile stress The formula is as follows:

[0088] Where: E: Elastic modulus of concrete α: Coefficient of linear expansion (approximately 1 × 10⁻⁶) -5 / ℃) ΔT: Temperature difference between inside and outside R: Constraint coefficient (0~1, depending on the degree of boundary constraint; in this embodiment, R is 0.75) The control unit 35 converts the thermal center elevation into the axial displacement required by the outer tube 3, generates the corresponding target lifting position parameters, and uses them as control commands to drive the subsequent action of the support lifting device 5.

[0089] Control unit 35 converts the center elevation of this section into the target axial displacement ΔL of the outer tube 3:

[0090] The formula for calculating the target's elevation / reclining position parameter L is:

[0091] In the formula: z 热中心 The elevation of the center of the thermal center interval (m); z 当前 The elevation (m) of the current position of outer pipe 3; its value is determined by the real-time elevation z of the lower end face of outer pipe 3. 底端 It is obtained by converting with the effective cooling coverage length L, that is

[0092] Z 底端 Displacement data can be obtained in real time through a displacement sensor installed on the lifting device 5. 初始 The initial installation position (m) of the outer tube 3 is given. Based on this, the control unit 35 drives the lifting device 5 to precisely align the effective cooling section of the outer tube 3 with the elevation range of the thermal center, thereby achieving directional cooling.

[0093] Step 6, Action of the support lifting device and adjustment of the outer tube 3: The control unit 35 sends start / stop and speed commands to the servo motor 9 in the support lifting device 5. The servo motor 9 drives the threaded rod 8 (worm gear) to rotate via the flexible coupling 22, which in turn drives the meshing turbine 10 to rotate. The drive gear 21, coaxially connected to the turbine 10, rotates accordingly. The drive gear 21 precisely meshes with the continuous helical external thread 31 on the outer wall of the outer tube 3. Under the constraint of the guide rail 7 and the limiting device 6, the rotational motion of the gear is converted into the axial lifting motion of the outer tube 3. At the same time, through the ball screw pair composed of the screw 13, the ball screw nut 14, and the ball 15, the support platform 11 is driven to lift synchronously, ensuring that the inner tube 2, the outer tube 3, and the relevant connecting parts remain coaxial and stable. The outer tube 3 is finally positioned at the elevation corresponding to the thermal center, achieving overlapping coverage of the cooling section and the high-temperature zone.

[0094] Step 7, targeted enhanced cooling and flow rate coordinated control, specifically: Once the outer pipe 3 has completed its ascent and descent and stabilized at the elevation of the thermal center, the control unit 35 locks the position of the servo motor 9 and applies a higher operating frequency command to the adjustable water pump 29. This causes the cooling water to circulate at a higher flow rate within the annular channel formed by the inner pipe 2 and the outer pipe 3, rapidly reducing the peak temperature at the thermal center through targeted enhanced heat exchange. During this process, the control unit 35 dynamically adjusts the water pump output based on the real-time flow rate and inlet / outlet water temperature feedback from the water flow monitoring sensor 28, ensuring that the cooling intensity and cooling rate remain within a safe and controllable range.

[0095] The term "fixed-point reinforcement" has two meanings: First, "fixed-point" means that the outer pipe 3 has been raised or lowered to the thermal center elevation and locked in position, and the cooling section precisely covers the high-temperature area and no longer moves; second, "reinforcement" means that on the basis of fixed-point, the water pump operating frequency is increased to a higher level than the warning level, increasing the circulation flow and heat exchange intensity, so as to achieve concentrated high-flow cooling for the high-temperature concentrated area, which is different from the global frequency increase heat dissipation strategy of the warning level.

[0096] The dynamic adjustment of the water pump output adopts a PID closed-loop control strategy: the control unit 35 uses the inlet and outlet water temperature difference ΔT_water (the difference between the inlet and outlet water temperatures, which is collected in real time by the water flow monitoring sensor 28) as the feedback signal, and the target cooling rate v_target (℃ / h) as the control target, and dynamically adjusts the operating frequency f of the water pump 29 according to the following formula:

[0097] In the formula: f0 is the reference frequency (Hz); e(t) = v 目标 -v 实际 For cooling rate deviation (°C / h); K n K i K l These are the proportional, integral, and derivative coefficients, determined through commissioning. When the outlet water temperature continues to rise, the control unit 35 automatically increases the water pump frequency; when the cooling rate exceeds the upper limit, it automatically reduces the frequency to prevent excessive temperature gradients from causing cracks.

[0098] Step 8, temperature tensile stress check and graded cooling protection, specifically: Based on real-time temperature data from the internal monitoring unit 32 and the near-surface monitoring unit 33, the control unit 35 calculates the corresponding temperature tensile stress by combining the concrete's elastic modulus, constraint conditions, and creep characteristics, and compares it with the design value of the concrete's tensile strength. When the temperature tensile stress approaches a preset safety threshold (e.g., 0.7 times the design value of the concrete's tensile strength), the system automatically enters a graded cooling protection mode: gradually reducing the operating frequency of the adjustable water pump 29 and the cooling water circulation flow rate, and if necessary, slowing down the lifting and lowering rhythm of the outer pipe 3 or maintaining its current position, so that the overall cooling rate is controlled within the specified upper limit (e.g., ≤ 2 ℃ / d), avoiding secondary temperature cracks caused by excessively rapid cooling.

[0099] Formula for temperature tensile stress:

[0100] In the formula: E is the elastic modulus of concrete (MPa), which is 30000 MPa for C30 concrete; α is the coefficient of linear expansion, which is taken as 1×10⁻⁶. -5ΔT is the temperature difference (°C) inside and outside the calculation point, obtained from real-time monitoring data; R is the constraint coefficient (0~1), which is taken according to the elevation location. R=0.75 is taken within 1 / 3 of the pier height from the bottom constraint surface, R=0.50 is taken in the middle, and R=0.30 is taken in the top free section; φ is the concrete creep coefficient, which is taken from 1.5 to 2.0, reflecting the relaxation effect of creep on temperature stress.

[0101] The graded cooling protection mode adopts a three-level stepped frequency reduction strategy, as follows: Level 1, when σ t ≥0.7f t At the first stage, the water pump operating frequency drops to 80% of the current value, and the target cooling rate is controlled at ≤2℃ / d; in the second stage, when σ t ≥0.85f t At this time, the water pump frequency is further reduced to 60% of the current value, the outer pipe 3 stops rising and falling and maintains its current position, and the target cooling rate is controlled at ≤1℃ / d; in the third gear, when σ t ≥0.95f t At this time, the water pump frequency drops to the lowest maintenance level, and the control unit 35 simultaneously issues an over-limit warning, with the target cooling rate controlled at ≤0.5℃ / d. The frequency reduction cutoff condition is: when the temperature tensile stress drops back to σ... t <0.7f t When the temperature difference between the inside and outside is on a continuous downward trend, the system determines that the risk has been eliminated and resumes normal control mode.

[0102] Step 9: Maintenance completion determination and system shutdown When the control unit 35 determines that the highest internal temperature of the concrete is close to the ambient temperature, the internal and external temperature difference ΔT at each monitoring elevation meets the relevant specifications and design requirements, and the concrete has reached the predetermined curing time (e.g., 14–28 days), it outputs a shutdown command, sequentially shutting down the adjustable water pump 29 and related electrical equipment, thus stopping the cooling water circulation loop. After this, the cooling water in the inlet pipe 18, return pipe 24, and cooling pipe assembly can be appropriately discharged or diverted as needed for construction, facilitating subsequent equipment recovery and construction operations.

[0103] The aforementioned "relevant specifications and design requirements" specifically refer to the following quantitative shutdown judgment conditions. When all three of the following conditions are met, the control unit 35 outputs a shutdown command: Condition 1, the difference between the highest internal temperature of the concrete and the ambient temperature ΔT ≤ 5℃; Condition 2, according to the "Standard for Construction of Mass Concrete" GB 50496-2018, the internal and external temperature differences at each monitoring elevation all meet ΔT ≤ 25℃; Condition 3, according to the "Code for Construction of Concrete Structures" GB 50666-2011, the concrete age is not less than 14 days. Step 10: The entire cooling pipe assembly is pulled out and recycled. After the cooling circuit stops operating and the necessary diversion treatment is completed, the connection between the inlet pipe 18 and the inner pipe 2, and the connection between the return pipe 24 and the upper guide tube 1 of the outer pipe are released through quick-connect coupling 17, and the fixation between the support 4 and the pier formwork is released. Then, using the support lifting device 5 or external lifting equipment, the inner pipe 2, the outer pipe 3, and the support device 31 (located at the bottom of the outer pipe 3) are pulled out of the concrete structure as a whole, and the residual cooling water in the pipes is taken out of the structure, realizing the recycling and reuse of the cooling pipe assembly, avoiding the formation of permanent foreign objects inside the concrete, and improving the integrity and durability of the structure.

Claims

1. A large-volume concrete temperature control system with liftable and rotatable cooling pipes, characterized in that: It includes an outer pipe (3), the upper end of the outer pipe (3) is connected to an upper outer pipe conduit (1), an inner pipe (2) is coaxially arranged inside the upper outer pipe conduit (1), the inner pipe (2) is connected to the water supply tank (30) through the water inlet pipe (18), the outer pipe (3) is connected to a lifting drive mechanism, the lifting drive mechanism is connected to the control system, and the upper outer pipe conduit (1) passes through the return water tank (26) through the return water pipe (24).

2. The large-volume concrete temperature control system with liftable and rotatable cooling pipes according to claim 1, characterized in that: The upper end of the inner tube (2) is connected to the water inlet pipe (18) via a quick connector (17).

3. The large-volume concrete temperature control system with liftable and rotatable cooling pipes according to claim 2, characterized in that: The outer tube (3) is coaxially sleeved outside the inner tube (2), and an annular cooling channel is formed between the outer tube (3) and the inner tube (2).

4. The large-volume concrete temperature control system with liftable and rotating cooling pipes according to claim 3, characterized in that: The lifting drive mechanism includes a motor (23), which is connected to a threaded rod (8) via a flexible coupling (22). The threaded rod (8) serves as a worm and forms a worm gear reduction pair with the turbine (10). The turbine (10) is coaxially connected to a drive gear (21), which is mounted on the inner ring of a ball bearing (19) via a rotating shaft. The outer ring of the ball bearing (19) is embedded in a bearing housing (20).

5. The large-volume concrete temperature control system with liftable and rotating cooling pipes according to claim 4, characterized in that: The bottom of the inner tube (3) is provided with a support device (31).

6. The large-volume concrete temperature control system with liftable and rotatable cooling pipes according to claim 4, characterized in that: The outer wall of the outer tube (3) is provided with a continuous spiral external thread that meshes with the drive gear (21).

7. The large-volume concrete temperature control system with liftable and rotatable cooling pipes according to claim 4, characterized in that: The upper conduit (1) of the outer tube extends vertically above the top of the outer tube (3). One end of the upper conduit (1) of the outer tube is connected to the upper end of the outer tube (3), and the other end of the upper conduit (1) of the outer tube is connected to the return water pipe (24) through a quick connector (17). The return water pipe (24) is connected to the return water pool (26).

8. The large-volume concrete temperature control system with liftable and rotatable cooling pipes according to claim 7, characterized in that: The control system includes a control unit (35), which is connected to a motor (23), a servo motor (9), a concrete internal monitoring unit (32), a near-surface monitoring unit (33), a water flow monitoring sensor (28), and a wireless communication module (34).

9. A control method for a large-volume concrete temperature control system with liftable and rotating cooling pipes, characterized in that: The specific steps are as follows: Step 1: The system is started and a cooling circuit is established; Step 2: Establish monitoring network initialization and baseline temperature; Step 3: Calculate the real-time temperature field and the temperature difference between inside and outside; Step 4: Temperature Anomaly Judgment and Early Warning Control; Step 5: Determine the location of the thermal center and the target elevation; Step 6: Adjust the height of the outer tube (3) by using the lifting drive mechanism to achieve overlap and coverage between the cooling section and the high-temperature zone; Step 7: Check the temperature tensile stress of the concrete and implement graded cooling protection based on the check results; Step 8: Determine the completion of concrete curing and shut down the system.

10. The control method for the temperature control system of large-volume concrete with liftable and rotating cooling pipes according to claim 9, characterized in that: The specific process of step 1 is as follows: After the concrete is poured, the control unit (35) issues a pump start command, and the adjustable water pump (29) draws cooling water from the water supply tank (30), and sends it into the inner pipe (2) through the water inlet pipe (18) and quick connector (17). The cooling water flows from top to bottom through the bottom of the inner pipe (2) and enters the annular cooling channel between the inner pipe (2) and the outer pipe (3). It flows from bottom to top, and after absorbing the heat of concrete hydration, it flows into the upper guide pipe (1) of the outer pipe through the top of the outer pipe (3), and then returns to the return water tank (26) through the return water pipe (24) in sequence, forming an inner inlet and outer outlet, annular heat exchange closed cooling circuit; The specific process of step 2 is as follows: The concrete internal monitoring unit (32) is embedded at different elevations and cross-sectional positions, the near-surface monitoring unit (33) is arranged at a distance of 30-50 mm from the outer surface of the component, and the water flow monitoring sensor (28) is installed on the inlet pipe (18), the return pipe (24) and the upper conduit (1) of the outer pipe. After the system is running normally, the concrete internal monitoring unit (32) and the near-surface monitoring unit (33) collect the concrete internal temperature and near-surface temperature at a preset sampling period. The water flow monitoring sensor (28) collects the cooling water flow rate and water temperature simultaneously. All data are uploaded to the control unit (35) through the wireless communication module (34) to establish the baseline of the initial temperature field distribution and the internal and external temperature difference ΔT. The specific process of step 3 is as follows: During the heat release process of concrete hydration, the control unit (35) continuously receives data from the concrete internal monitoring unit (32) and the near-surface monitoring unit (33), performs paired calculations on the internal temperature and near-surface temperature at the same elevation, and calculates the internal and external temperature difference ΔT = T in real time. 内 T 表 And identify the current highest temperature point and the elevation range where the maximum ΔT is located; The specific process of step 4 is as follows: When the internal and external temperature difference ΔT at any monitoring elevation reaches the warning threshold, the control unit (35) determines that there is an abnormal temperature trend in the area and enters the warning level control mode. In this mode, the control unit (35) increases the operating frequency of the adjustable water pump (29) based on the real-time data of the water flow monitoring sensor (28). The specific process of step 5 is as follows: When the temperature difference between the inside and outside ΔT continues to increase and reaches the intervention level threshold, the control unit (35) determines the elevation range of the internal thermal center of the concrete based on the temperature distribution of the internal monitoring unit (32) at different elevations. The control unit (35) converts the thermal center elevation into the axial displacement required by the outer pipe (3) and generates the corresponding target lifting position parameters as the control command for the subsequent driving of the support lifting device (5). The specific process of step 6 is as follows: The control unit (35) issues start / stop and speed commands to the servo motor (9) in the support lifting device (5). The servo motor (9) drives the threaded rod (8) to rotate via the flexible coupling (22), which in turn drives the turbine (10) to rotate. The drive gear (21) coaxially connected to the turbine (10) rotates accordingly. The drive gear (21) meshes with the continuous spiral external thread on the outer wall of the outer tube (3), and the outer tube (3) moves up and down in the vertical direction. When the outer tube (3) completes the lifting and stabilizing at the elevation of the thermal center, the control unit (35) locks the position of the servo motor (9) and applies a frequency command to the adjustable water pump (29) so that the cooling water circulates in the annular channel formed by the inner tube (2) and the outer tube (3). The specific process of step 7 is as follows: The control unit (35) calculates the tensile stress at the corresponding temperature based on the real-time temperature data of the internal monitoring unit (32) and the near-surface monitoring unit (33), and compares it with the design value of the tensile strength of concrete. When the calculated stress approaches the preset safety threshold, the system automatically enters the graded cooling protection mode: gradually reducing the operating frequency of the adjustable water pump (29) and the cooling water circulation flow rate. The specific process of step 8 is as follows: When the control unit (35) determines that the highest internal temperature of the concrete reaches the ambient temperature, the internal and external temperature difference ΔT at each monitoring elevation meets the preset requirements, and the concrete age reaches the predetermined curing time, it outputs a shutdown command to stop the cooling water circulation loop.

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