An ultrasonic on-line detection system for continuously winding glass steel pipe

Abstract

The application discloses an ultrasonic online detection system for continuously winding glass steel pipes, and belongs to the technical field of pipeline nondestructive detection. The system integrates a multichannel ultrasonic detection module, an ultrasonic probe, a water tank, a water storage tank, a water circulation filtering system, a water tank position adjusting mechanism, a marking machine, an electric control system and an upper computer. By adopting the multichannel ultrasonic detection module and the low-frequency large-size ultrasonic probe, combining the pulse echo technology and the dynamic parameter adjusting technology, the system is adapted to different wall thicknesses and avoids missing detection. The position adjusting mechanism, the flexible water tank and the gate tracking technology are used to adaptively compensate for the pipeline jumping and unevenness. The multi-factor coupled sound velocity calibration module is innovatively proposed to real-time correct the influence of high temperature, wall thickness and sand distribution on the sound velocity, and significantly improve the defect positioning accuracy. The system has real-time imaging, defect alarm and statistical functions, and realizes efficient and accurate online detection of internal defects of the pipeline.

Description

Technical Field

[0001] This invention relates to the field of non-destructive testing technology for pipelines, specifically to an ultrasonic online testing system for continuously wound fiberglass pipes. Background Technology

[0002] With the widespread application of industrial pipeline systems, especially in the fields of chemical, petroleum, natural gas and water supply, the requirements for pipeline quality and safety are increasing. Continuous wound fiberglass pipes, as an important type of non-metallic pressure pipeline, are widely used in many industrial fields due to their excellent corrosion resistance and high strength. However, various defects may occur in the pipeline during production and use, such as cracks, pores, inclusions, etc. If these defects are not detected and treated in time, they will seriously affect the service life and safety of the pipeline.

[0003] In the automated production process of continuously wound fiberglass reinforced plastic (FRP) pipes, achieving real-time and accurate detection of internal defects has always been a technical challenge in the industry. Currently, the commonly used offline inspection method involves removing the completed pipes from the production line for individual inspection, which suffers from significant detection lag and cannot immediately detect and locate typical defects such as delamination, bubbles, and uneven resin distribution during production, making it difficult to effectively control potential quality issues. Although ultrasonic testing technology has been maturely applied in the online inspection of metal pipes, the fundamental differences in material composition and processing characteristics between FRP pipes and metal pipes mean that directly transplanting existing technology faces several bottlenecks: First, the continuous winding process uses a spiral forward forming method, making it impossible to place inspection probes inside the pipe, rendering transmission-based ultrasonic testing technology completely unsuitable; only echo-based single-sided inspection is possible. However, the pipe is composed of glass fiber, resin, and sand, and this multiphase, non-uniform structure exhibits strong attenuation and scattering characteristics for ultrasonic waves. Especially for thick-walled pipes, conventional ultrasonic probes lack sufficient energy, making effective detection across the entire wall thickness difficult. Secondly, under production conditions, the pipe surface exhibits obvious circumferential ripples and axial undulations, accompanied by mechanical vibrations during rotation. This causes continuous fluctuations in the detection distance and coupling state, failing to meet the basic requirements of traditional ultrasonic testing for coupling stability. Furthermore, the pipe temperature on the production line typically exceeds 90℃. When using water coupling for online testing, the local temperature field constantly changes due to the cooling water, causing dynamic drift in the material's sound velocity. If fixed sound velocity parameters are used for defect location, significant measurement errors will occur. Currently, there is a lack of mature technical solutions both domestically and internationally that can simultaneously address these issues: existing metal pipe testing technologies are developed based on the premise of material uniformity, surface smoothness, and stable acoustic characteristics, which are completely unsuitable for the complex structure, severe attenuation, and complex operating conditions of FRP (fiberglass reinforced plastic) pipes; while conventional ultrasonic testing for composite materials is mostly limited to offline, static scenarios, lacking compensation mechanisms for coupling fluctuations, temperature changes, mechanical vibrations, and other factors in online production environments. This technological gap severely restricts the improvement of quality and intelligent development of continuously wound FRP pipe production processes. Therefore, there is an urgent need to develop a dedicated online ultrasonic testing system that can adapt to complex production processes, overcome multiple interference factors, and achieve accurate detection of the entire wall thickness, in order to meet the stringent quality control requirements of the modern pipeline manufacturing industry.

[0004] To address the aforementioned problems, the present invention proposes an ultrasonic online inspection system for continuously wound fiberglass pipes, which is of particular importance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an ultrasonic online inspection system for continuously wound fiberglass pipes. This system can achieve efficient and accurate online inspection of pipe defects by integrating a multi-channel ultrasonic inspection module, a low-frequency large-size ultrasonic probe, a water tank position adjustment mechanism, a water circulation filtration system, a marking machine, a sound velocity dynamic calibration module, and an electrical control system component. Specifically, the system employs high-excitation voltage low-frequency ultrasonic detection technology based on pulse echo combined with dynamic parameter adjustment technology. This overcomes ultrasonic scattering and attenuation caused by the complex pipe structure, achieving full-thickness sound beam coverage for pipes with varying wall thicknesses. The multi-probe arrangement based on multi-channel modules ensures sufficient overlap of the scanning area, effectively avoiding missed detections. Utilizing a flexible water tank, a water tank position adjustment mechanism, and gate dynamic tracking technology, the system can adaptively compensate for unevenness and rotational vibrations on the pipe surface, resolving data acquisition instability issues. The newly added dynamic sound velocity calibration module can correct the effects of pipe temperature fluctuations, wall thickness differences, and varying sand and gravel ratios on sound velocity in real time, ensuring defect location accuracy. Simultaneously, the host computer software supports various real-time imaging displays and features multi-channel defect alarms, location recording, and statistical functions, further improving detection efficiency and accuracy.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an ultrasonic online testing system for continuously wound fiberglass pipes, the system comprising the following components: a multi-channel ultrasonic testing module, an ultrasonic probe, a water tank, a water storage tank, a water circulation filtration system, a water tank position adjustment mechanism, a marking machine, an electrical control system, and a host computer;

[0007] The multi-channel ultrasonic detection module is connected to the ultrasonic probe and is used to generate a high-voltage negative square wave signal and receive the reflected ultrasonic signal. It converts the signal into an electrical signal and transmits it to the host computer after AD conversion. The multi-channel ultrasonic detection module integrates a pulse generator receiver and a high-speed data acquisition card and has multiple ultrasonic pulse generator and receiver channels.

[0008] The ultrasonic probe: adopts a low frequency and large size probe of 0.2MHz and 0.5MHz, arranged along the pipeline axis at a preset spacing to ensure that the scanning area overlaps by 20% or more, and at least 2 sets are arranged. The probe chip size d≥1.25s, where s is the distance the pipeline advances in one revolution. The probe spacing is set to an integer multiple of s and greater than the probe diameter d, and is used to generate and receive ultrasonic waves.

[0009] The water tank is fixed inside the water storage tank and is made of any one or more of the following materials: acrylic sheet with a heat resistance temperature exceeding 100℃, rubber elastomer, nylon, etc. It has a water inlet and a water outlet on one side perpendicular to the pipe axis, and the top of the two sides perpendicular to the pipe axis is designed with an arc and a hollow silicone water-blocking strip on the top of the arc surface. The bottom of the water tank has an ultrasonic probe fixing hole. After fixing the probe, it is sealed to prevent water leakage, so as to provide a water immersion detection environment.

[0010] The water storage tank is located below the water tank and has a positioning block inside. It has an ultrasonic probe wire hole at the bottom, a positioning sensor on one side, and an infrared temperature sensor on the other side to monitor the pipe surface temperature after water immersion testing. It is fixed on a two-axis electric displacement stage by a support frame to store water overflowing from the water tank and to assist in signal calibration.

[0011] The water circulation system is connected to the inlet of the water tank and the outlet of the water storage tank. It is used to circulate and filter the water during the testing process, so as to realize the recycling of water.

[0012] The water tank position adjustment mechanism includes a support frame, a two-axis electric displacement stage, an electric lifting stage, and a base. The support frame is fixedly supporting the water storage tank and the water tank and is installed on the two-axis electric displacement stage. The two-axis electric displacement stage is fixed on the electric lifting stage. Both are driven by servo motors. The electric lifting stage is equipped with an infrared proximity switch to adjust the position of the water tank to ensure the stability of the detection posture of the ultrasonic probe and the pipeline.

[0013] The marking machine is used to mark the location of defects and operates after receiving a trigger signal sent by the electronic control system.

[0014] The sound velocity dynamic calibration module communicates in real time with the infrared temperature sensor of the water storage tank and the multi-channel ultrasonic detection module. The sound velocity dynamic calibration module dynamically calculates and corrects the actual sound velocity of the FRP pipe material based on the actual pipe surface temperature collected by the infrared temperature sensor, the actual thickness transmitted by the pipe production equipment, and the preset material structure parameters. The corrected data is fed back to the multi-channel ultrasonic detection module in real time to adjust the ultrasonic signal excitation and reception parameters. At the same time, it updates the sound velocity reference value in the upper computer imaging algorithm to ensure the accuracy of defect location and size determination.

[0015] The electrical control system includes control circuits for a water circulation filtration system, a marking machine, a two-axis electric displacement table, and an electric lifting table, which are used to control the coordinated operation of each component.

[0016] The host computer is equipped with motion control software and ultrasonic testing software. The ultrasonic testing software supports three real-time imaging display modes: A, B, and C. The C-scan imaging uses the pipe's forward direction as the X-axis and the pipe's circumference direction as the Y-axis. It has real-time multi-channel defect alarm, defect location recording, and defect statistics functions, and is used for signal processing, imaging display, defect judgment, and system control.

[0017] Furthermore, the multi-channel ultrasonic testing module can dynamically adjust the amplitude and pulse width of the high-pressure negative square wave signal according to the pipe thickness, wherein the formula for adjusting the amplitude of the high-pressure negative square wave signal is: ,in The final output is the amplitude of the high-voltage negative square wave signal. The baseline amplitude is set at 200V. This value was determined through preliminary testing experiments on 100 sets of continuously wound fiberglass pipes of different specifications. At this baseline value, effective testing of pipes with a thickness of 5mm-10mm can be achieved. The amplitude adjustment coefficient, set to 0.51, is determined based on the linear fitting results of the signal attenuation law as the pipe thickness increases by 1 mm. Through signal attenuation tests on pipes with thicknesses ranging from 10 mm to 70 mm, the slope of the logarithmic relationship between attenuation and thickness was found to be 0.51. The actual thickness of the pipe to be inspected is obtained in real time from the parameter system of the pipe production equipment. The reference pipe thickness is used; the number of channels in the multi-channel ultrasonic testing module can be set according to the pipe circumference and testing efficiency requirements. The sampling rate of a single channel is not less than 100MHz. The received ultrasonic signal is transmitted to the host computer after 16-bit AD conversion, ensuring that the accuracy loss during the signal conversion process is less than 0.5%, which meets the requirements for identifying small defects inside the pipe.

[0018] Furthermore, the thermal conductivity of the water tank material must meet the following requirements. Various materials are tested and screened using a thermal conductivity tester. This thermal conductivity ensures stable ultrasonic signal propagation speed by preventing drastic fluctuations in water temperature due to changes in ambient temperature during testing. The water inlet is connected to a water source, and the water circulation and filtration system is connected to the water inlet. The water flow rate can be automatically adjusted according to the tank volume and testing rhythm. The formula for calculating the water flow rate is: ,in For water injection flow rate, The water tank volume is determined based on the pipe diameter and the number of probes. For example, when the pipe diameter is 200mm, the water tank volume is 5L. The time correction factor, with a value of 0.05, is determined based on the statistical results of water tank leakage rate in multiple water filling experiments. It can compensate for minor water leakage caused by sealing gaps in the water tank. This refers to the duration of a single test, ranging from 1 to 5 minutes, determined by the pipeline production rate. The water injection duration is set at 0.5 minutes, a fixed duration to ensure continuous testing; the radius of the top arc on both sides perpendicular to the pipe axis. , The outer diameter of the pipe to be tested is increased by 5mm to prevent friction between the pipe and the side of the water tank during pipe movement. The compression of the hollow silicone water-blocking strip can be adaptively adjusted according to the pipe's runout. , The compression coefficient, set to 1.2, was determined through real-time monitoring of pipe vibration and experimental verification of the water-blocking effect. This ensures that the water-blocking strip can still effectively seal the pipe even when it vibrates. The maximum pipe runout is measured in the range of 1mm-5mm, determined by vibration testing results from the pipe manufacturing equipment. The ultrasonic probe mounting holes at the bottom of the water tank are sealed with silicone sealing rings to prevent leakage; the sealing pressure must meet the specified requirements. The sealing performance test confirmed that this pressure can prevent water from leaking from the orifice and affecting the detection.

[0019] Furthermore, the positional accuracy of the positioning blocks inside the water storage tank must meet the following requirements. The positioning block installation position is calibrated using a coordinate measuring machine. This accuracy ensures the water tank is fixed in the center of the water storage tank, preventing probe detection position deviation due to water tank offset. The ultrasonic probe's wiring hole below is sealed with a rubber gasket to prevent leakage. The gasket's Shore hardness is 50HA-60HA, selected through sealing tests. This hardness range ensures a good seal while avoiding damage to the probe cable. The detection accuracy of the positioning sensor on one side must meet the following requirements. By calibrating the sensor's detection accuracy using a laser rangefinder, the distance between the water tank and the pipe surface can be ensured to be controlled within the optimal detection range of 2mm-5mm. When the detected distance between the water tank and the pipe surface reaches a preset value... At this time, the electric lifting platform is triggered to stop moving, with a value of 3mm, determined based on ultrasonic signal strength testing, at which distance the ultrasonic signal reflection intensity is maximum; the infrared temperature sensor on the other side has a temperature measurement range of 0°C-100°C, and a measurement accuracy of ± The sensor is calibrated using a standard temperature source to calibrate the sound velocity of the material. The calibration formula is as follows: ,in The calibrated material sound velocity, The reference speed of sound is 2300 m / s, which is the standard speed of sound for fiberglass pipes at 25°C. The sound velocity temperature correction factor, with a value of 0.0015, was obtained by fitting the sound velocity data of fiberglass pipe materials at different temperatures. The actual temperature of the pipe surface at the detection location is measured by an infrared temperature sensor. The reference temperature is used; the load-bearing capacity of the support frame under the water storage tank must be greater than 1.5 times the total weight of the water storage tank, water tank and water. This is determined through structural strength calculations to ensure that the support frame does not deform during the testing process.

[0020] Furthermore, the water circulation filtration system includes a water pump, a filter, a flow meter, and a pressure sensor, and the water pump head must meet the requirements. ,in For the water pump head, The height difference between the water tank and the storage tank, ranging from 0.5m to 1m. The pipeline resistance coefficient, taken as 0.1 m / m, is calculated based on the pipeline diameter and length. The total pipeline length is 5m-10m to ensure sufficient water circulation power; the filter's filtration accuracy is 5μm, determined by analyzing the particle size of impurities in the test water, capable of filtering out tiny impurities that affect ultrasonic signal propagation, with a filtration efficiency greater than 95%; the flow meter monitors the water circulation flow rate in real time and feeds it back to the electrical control system; when the flow rate falls below a preset threshold... At that time, based on the requirement to ensure the water quality renewal rate in the tank, the electronic control system controls the water pump to increase its speed to increase the flow rate; the pressure sensor monitors the pressure of the water circulation system in real time, and when the pressure exceeds the preset maximum value... When the system automatically alarms and stops the water pump, the water circulation filtration system is also equipped with a turbidity sensor. The turbidity threshold is set to 5 NTU. This was determined through experiments on the relationship between ultrasonic signal propagation speed and water turbidity. When the turbidity exceeds 5 NTU, the ultrasonic signal attenuation exceeds 10%, affecting the detection accuracy. When the turbidity exceeds the threshold, the system prompts to replace the filter cartridge.

[0021] Furthermore, in the water tank position adjustment mechanism, the positioning accuracy of the X-axis of the two-axis electric displacement stage along the pipe axis and the Y-axis perpendicular to the pipe axis are both... By calibrating the displacement stage using a laser interferometer, the horizontal positioning accuracy of the water tank can be ensured, with a repeatability accuracy of [missing information]. The vertical positioning accuracy of the Z-axis of the electric lifting platform is: The repeatability accuracy is The lifting speed adjustment range is 1mm / s-10mm / s to meet the needs of different detection rhythms; the rated torque of the servo motors used in the two-axis electric displacement stage and electric lifting stage must meet the requirements. ,in The rated torque of the motor. The torque required to overcome the friction of the displacement stage itself is taken as 0.5 N·m. The load factor is 0.001 N·m / N. The total load force borne by the displacement stage is set within the range of 500N-1000N to ensure sufficient motor drive capability. The detection distance range of the infrared proximity switch on the electric lifting platform is 5mm-20mm, which has been determined through experiments. This ensures accurate triggering when the pipeline moves to the detection position, with a trigger response time of less than 1ms. When the pipeline moves above the sensor, it triggers the ultrasonic detection system to start working and simultaneously sends a position signal to the electrical control system to ensure coordinated operation of all modules.

[0022] Furthermore, the marking machine adopts an erasable inkjet marking method, with a marking accuracy of [missing information]. The marking speed, determined through marking experiments, can accurately mark defect locations. The marking speed can be adaptively adjusted based on the pipeline's movement speed. The formula for calculating the marking speed is: ,in For the marking speed of the marking machine, The speed of the pipeline movement is obtained in real time from the pipeline production equipment. The speed compensation coefficient, set to 0.05, is determined based on test results of the marking machine's response delay. It compensates for the marking machine's response time and prevents marking position deviation. The marking content includes the defect size. When the host computer determines a defect, it sends a trigger signal to the marking machine through the electronic control system. The delay time of the trigger signal is less than 0.5ms. Simultaneously, the marking machine sends a marking completion signal back to the electronic control system, ensuring that each defect is accurately marked. The erasable inkjet marking uses special environmentally friendly biodegradable ink. The marking can be removed by wiping with water or a special cleaning agent, avoiding physical damage to the pipe surface and ensuring the pipe's subsequent reuse, secondary processing, or refurbishment needs. The marking machine is equipped with an ink level monitoring module. When the ink level is less than 10% of the total capacity, it sends an ink replenishment reminder signal to the electronic control system.

[0023] Furthermore, the electrical control system uses a PLC controller as the core control unit. The PLC has at least 32 digital input points, at least 16 digital output points, at least 8 analog input points, and at least 4 analog output points. The PLC's scan cycle is less than 10ms, and its program storage capacity is at least 1MB. The signal isolation of the electrical control system uses optocouplers with an isolation voltage greater than 2500VAC. The electrical control system is equipped with an emergency stop button. When the system malfunctions, pressing the emergency stop button will immediately cut off the power to all actuators, ensuring the safety of equipment and personnel. The electrical control system also has a fault self-diagnosis function, which can diagnose sensor faults, motor faults, communication faults, etc., and display the fault code and fault cause on the display screen, facilitating maintenance personnel to quickly troubleshoot the fault.

[0024] Compared with existing technologies, this ultrasonic online inspection system for continuously wound fiberglass pipes has the following advantages:

[0025] I. This invention employs high-excitation voltage low-frequency ultrasonic technology based on pulse echo, using high excitation voltage to compensate for signal loss. Combined with dynamic parameter adjustment, it can automatically match detection parameters according to the pipe wall thickness, achieving full-thickness acoustic beam coverage for pipes of different wall thicknesses. This overcomes the challenges of strong scattering and high attenuation of ultrasonic signals in continuously wound fiberglass pipes, and the difficulty in adapting to different wall thicknesses due to fixed parameters. Simultaneously, relying on a multi-channel ultrasonic detection module and multi-probe configuration ensures sufficient overlap of the scanning area. Combined with real-time imaging in A, B, and C modes, along with defect alarm and statistical functions, it effectively avoids missed detections, improving detection accuracy and defect detection capability.

[0026] Second, this invention replaces the traditional rigid coupling structure with a flexible water tank and a water tank position adjustment mechanism, so that the water tank and the pipe surface can adaptively fit together, fundamentally solving the problem of unstable detection signal caused by unstable coupling. At the same time, it integrates a water circulation filtration system to purify the coupled water quality in real time and avoid interference from sand and gravel impurities, realizing water resource recycling and adaptive water flow adjustment. Combined with gate dynamic tracking technology, it adapts to the undulations of the pipe surface, realizing efficient, stable and automated online detection of pipe defects.

[0027] Third, this invention proposes a multi-factor coupled dynamic calibration method for sound velocity. By establishing a three-dimensional calibration model of "temperature-wall thickness-sand inclusion distribution" and combining it with components such as infrared sensors, the pipe detection temperature is collected in real time, and the ultrasonic sound velocity is dynamically corrected to achieve accurate location of defects. This solves the problem that traditional sound velocity calibration methods for metal pipes cannot adapt to the sound velocity fluctuations caused by changes in temperature, wall thickness, and sand inclusion distribution in non-metallic fiberglass pipes, and fills the technical gap of "no dynamic correction of sound velocity" in existing online ultrasonic testing of large non-metallic pipes. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0029] Figure 1 This is a flowchart illustrating the operation of an online ultrasonic testing system for continuously wound fiberglass pipes.

[0030] Figure 2 This is a connection diagram of an ultrasonic online testing system for continuously wound fiberglass pipes. Detailed Implementation

[0031] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0032] Example 1

[0033] According to the system composition requirements, the assembly of the continuous winding fiberglass pipe ultrasonic online inspection system was completed. The selection and installation of each component must strictly match the inspection requirements of large-diameter thick-walled pipes to ensure system stability and inspection accuracy. The multi-channel ultrasonic inspection module integrates a pulse generator receiver and a high-speed data acquisition card, and has multiple ultrasonic pulse generator and receiver channels. Its core function is to efficiently excite ultrasonic signals and accurately receive reflected signals, providing a foundation for subsequent signal processing. This module is connected to the ultrasonic probe through a dedicated cable to ensure interference-free signal transmission. The ultrasonic probe uses a 0.5MHz low-frequency 40mm crystal diameter. The low-frequency characteristics ensure stronger penetration of ultrasonic waves in thick-walled pipes, effectively covering the 35mm full wall thickness inspection range of the pipe to be inspected. The large size design improves signal reception sensitivity. Arranged along the pipe axis at preset intervals, it can achieve a comprehensive scan of the pipe circumference and avoid missed detection in local areas.

[0034] The water tank is made of rubber with a heat resistance exceeding 100℃. This rubber material not only meets heat resistance requirements but also possesses good structural strength, maintaining shape stability during long-term testing. Its thermal conductivity meets the requirement of ≤0.5W / (m・K), effectively reducing the impact of temperature exchange between the inside and outside of the water tank on the testing environment and preventing changes in ultrasonic wave propagation speed due to water temperature fluctuations, thus ensuring testing accuracy. The water tank is fixed inside a water storage tank. A water inlet and a water outlet are installed on the side parallel to the pipe axis. The water inlet connects to a water source for initial and subsequent water replenishment, while the water outlet connects to a water circulation and filtration system for water recycling. Together, these components ensure a stable water level within the tank, providing a continuous and uniform coupling medium for ultrasonic testing. The tops of the two sides perpendicular to the pipe axis are rounded. Based on the outer diameter of the pipe to be tested (1800mm), the radius of the arc is set to 905mm. This design minimizes the gap between the pipe and the side of the water tank during pipe movement, while preventing friction between the pipe and the water tank, protecting the pipe surface and ensuring the stability of the water tank structure. A hollow silicone water-blocking strip is installed at the top of the arc surface. The water-blocking strip has good elasticity and can fit tightly against the pipe surface, effectively preventing water from overflowing during pipe movement and maintaining a dry and clean testing environment. An ultrasonic probe fixing hole is provided at the bottom of the water tank. After fixing the probe, a silicone sealing ring is used to seal it to prevent leakage, ensuring a sealing pressure ≥0.2MPa. This pressure value can completely block water from seeping from the hole, preventing leakage from affecting the working state of the ultrasonic probe and the accuracy of the test data, while also protecting the internal circuitry of the probe from water immersion damage.

[0035] A positioning block is installed inside the water storage tank, with a positioning accuracy controlled within ±0.1mm. This high-precision positioning block ensures the water tank is accurately positioned within the tank, preventing deviations in the relative position of the ultrasonic probe and the pipeline due to tank misalignment, which could affect the test results. An ultrasonic probe cable insertion hole is located at the bottom of the water storage tank, sealed with a rubber gasket with a Shore hardness of 55HA to prevent leakage. This rubber gasket combines sealing and elasticity, preventing water leakage from the storage tank through the insertion hole and tightly wrapping the probe cable after it passes through, while also preventing damage from compression. A positioning sensor is installed on one side of the water storage tank. With a detection accuracy of ±0.05mm, the high-precision positioning sensor can monitor the distance between the water tank and the pipe surface in real time, providing accurate data support for water tank position adjustment, ensuring that the ultrasonic probe maintains the optimal detection distance with the pipe surface, and guaranteeing the strength and stability of the detection signal. An infrared temperature sensor is installed on the other side, with a temperature measurement range of 0°C-100°C and a measurement accuracy of ±0.5°C. This temperature measurement range and accuracy can fully cover the temperature change range during pipe production, accurately obtaining the actual temperature of the pipe surface at the detection location, providing reliable data for material sound velocity calibration. The calibration formula is: ,in The calibrated material sound velocity, As the reference speed of sound, This is the temperature correction factor for the speed of sound. The actual temperature of the pipe surface at the detection location is measured by an infrared temperature sensor. The reference temperature is used; the water tank is fixed on the two-axis electric displacement table by a support frame. The load-bearing capacity of the support frame is more than 1.5 times the total weight of the water tank, water tank and water. The sufficient load-bearing margin can ensure that the support frame will not deform or be damaged under long-term load, ensuring the stability of the entire water tank and water tank structure and avoiding the impact of structural shaking on the detection accuracy.

[0036] The water circulation filtration system connects the inlet of the water tank and the outlet of the storage tank, forming a complete water circulation loop. It includes a water pump, filter, flow meter, pressure sensor, and turbidity sensor, each with its own function. The water pump provides power for water circulation, ensuring smooth water flow within the system. The filter has a filtration accuracy of 5μm and a filtration efficiency greater than 95%. This accuracy effectively filters impurities, debris, and other pollutants from the water, preventing impurities from adhering to the surface of the ultrasonic probe or pipes, thus avoiding interference with ultrasonic wave propagation and detection signal quality. The flow meter monitors the water circulation flow rate in real time and feeds the data back to the electrical control system, allowing the system to adjust the pump's operating status according to flow changes, ensuring stable water circulation flow and providing a uniform coupling environment for ultrasonic testing. The pressure sensor monitors the system pressure in real time, preventing excessive pressure due to pipe blockage or other reasons, thus protecting equipment safety. The turbidity sensor monitors water quality, with a turbidity threshold set at 5 NTU. When the turbidity exceeds the threshold, it promptly prompts for filter replacement, ensuring that the circulating water quality always meets the testing requirements.

[0037] The water tank position adjustment mechanism consists of a support frame, a two-axis electric displacement stage, an electric lifting stage, and a base. The positioning accuracy of the two-axis electric displacement stage on both the X and Y axes is ±0.01mm, and the repeatability is ±0.005mm. This high positioning and repeatability ensures that the water tank accurately follows the pipe movement in the horizontal direction, preventing misalignment of the detection area due to slight pipe deviation. The electric lifting stage has a Z-axis positioning accuracy of ±0.02mm, a repeatability of ±0.01mm, and a lifting speed adjustment range of 1mm / s-10mm / s. This vertical accuracy ensures that the water tank can be precisely adjusted in height to maintain the optimal distance between the ultrasonic probe and the pipe surface. The lifting speed range meets the needs of different detection rhythms, allowing for rapid position adjustment during rapid pipe production to ensure detection efficiency. An infrared proximity switch is installed on the platform, with a detection distance range of 5mm-50mm and a trigger response time of less than 1ms. This short response time ensures that the system can immediately start the detection process when the pipe moves to the detection area, avoiding missed detection opportunities. The detection distance range can accommodate slight vibrations on the pipe surface, ensuring stable sensor triggering.

[0038] The marking machine uses laser marking with a marking accuracy of ±0.1mm. High-precision laser marking ensures accurate marking at the defect location, making it easy for subsequent staff to quickly locate the defect for repair or evaluation. The marking machine is equipped with a cooling system that can cool down the machine in time during long-term operation, preventing performance degradation or damage due to excessive temperature and ensuring continuous and stable operation.

[0039] The electrical control system is centered around a PLC controller, featuring 32 digital input points, 16 digital output points, 8 analog input points, and 4 analog output points. This ample number of input / output points meets the signal acquisition and control requirements of various system components, enabling coordinated control of multiple parts such as the water circulation filtration system, marking machine, and displacement stage. The PLC scan cycle is less than 10ms, ensuring the system can quickly process signals from various sensors and issue control commands promptly, guaranteeing synchronized operation of all components and preventing delays in the detection process. With a program storage capacity of ≥1MB, the system can accommodate complex control programs, meeting diverse system requirements. The system is designed to meet testing requirements and facilitate future functional expansion. Signal isolation in the electrical control system utilizes optocouplers with an isolation voltage greater than 2500VAC. This high isolation voltage effectively blocks external interference signals from entering the system, preventing control signal errors caused by interference and ensuring stable system operation. An emergency stop button is included; pressing this button immediately cuts off power to all actuators in case of system malfunction, preventing the accident from escalating and ensuring equipment and personnel safety. The system also features self-diagnostic capabilities, capable of diagnosing sensor faults, motor faults, communication faults, etc., and displaying fault codes and causes on the screen. This function helps maintenance personnel quickly locate fault points, shorten maintenance time, and improve system utilization.

[0040] During the testing of continuously wound fiberglass tubes (outer diameter 1800mm, thickness 35mm), the sound velocity dynamic calibration module operates according to the following procedure:

[0041] 1) Triggering mechanism: When the infrared temperature sensor detects that the temperature of the detection tube surface drops from the initial 90℃ to 73℃ (fluctuation exceeding ±2℃), the system automatically triggers calibration;

[0042] 2) Data Acquisition: The host computer synchronously acquires the temperature T=73℃, the actual pipe thickness δ=35.2mm (a change of 0.57% from the reference thickness of 35mm), and the sand inclusion layer distribution coefficient k. 10 =0.03 (The sand content of this pipe is 35%, corresponding to the coefficient value determined by the experiment).

[0043] 3) Sound speed calculation: Substituting into the formula v_real=2300×(1−0.0015×(33−25))×(1−0.03×(35.2−35) / 35)=2300×0.928×0.9997≈2134m / s;

[0044] 4) Parameter application: The multi-channel ultrasonic testing module adjusts the ultrasonic signal defect gate range window (from the original 8.7μs to 9.4μs) according to v_real=2134m / s; in the A and B scanning imaging of the host computer, the sound velocity conversion coefficient in the pipeline depth direction is updated synchronously to ensure that the defect depth location error is reduced from 8.8% to within ±1%.

[0045] The host computer is equipped with motion control software and ultrasonic testing software. The motion control software enables precise control of moving components such as the two-axis electric displacement stage and electric lifting stage, ensuring they move along preset trajectories. The ultrasonic testing software supports three real-time imaging display modes: A, B, and C. A-scan imaging displays the propagation waveform of ultrasonic waves within the pipeline, helping technicians analyze the internal structure of the pipeline. B-scan imaging presents the cross-sectional image of the pipeline, while C-scan imaging shows the distribution of defects on the pipeline surface. The combination of these three imaging modes provides a comprehensive view of the pipeline inspection, facilitating accurate defect identification. The software features a real-time multi-channel defect alarm function, which immediately issues an alarm signal when a defect is detected, alerting staff to prevent defects from being missed. The defect location recording function automatically records the specific location of defects on the pipeline, including axial and circumferential coordinates, providing a basis for subsequent traceability and analysis. The defect statistics function can statistically analyze the type, quantity, and size of defects found during the inspection process, generating reports to facilitate staff evaluation of pipeline production quality and optimization of production processes.

[0046] Example 2

[0047] Based on the structural requirements, the assembly and debugging of each component of the system were completed. The multi-channel ultrasonic testing module was connected to the ultrasonic probe. This module integrates a pulse generator and receiver and a high-speed data acquisition card, and has multiple ultrasonic pulse generator and receiver channels. The ultrasonic probes selected are 0.2MHz low frequency 50mm crystal diameter and 0.5MHz low frequency 50mm crystal diameter. The penetration of the 0.2MHz probe and the better resolution of the 0.5MHz probe are used to achieve sound beam coverage of the entire 50mm wall thickness of the pipe to be tested. The probes are arranged at preset intervals along the pipe axis.

[0048] The water tank is made of acrylic sheet material with a heat resistance exceeding 100℃ and a thermal conductivity of ≤0.5W / (m・K). It is installed inside the water storage tank. The side of the water tank parallel to the pipe axis is equipped with a water inlet and a water outlet. The water inlet is connected to the water source, and the water outlet is connected to the water circulation filtration system. The top of the two sides perpendicular to the pipe axis is designed with an arc. The outer diameter of the pipe to be tested is 2200mm, and the radius of the arc is set to 1105mm. A hollow silicone water-blocking strip is installed on the top of the arc surface. The compression amount of the water-blocking strip is adaptively adjusted according to the maximum runout of the pipe using the water-blocking strip compression amount calculation formula. The fixing hole of the ultrasonic probe at the bottom of the water tank is sealed with a silicone sealing ring to ensure a sealing pressure ≥0.2MPa.

[0049] The positioning accuracy of the internal positioning block of the water storage tank is controlled within ±0.1mm. The ultrasonic probe wire hole below is sealed with a rubber sealing gasket with a Shore hardness of 50HA. A positioning sensor with a detection accuracy of ±0.05mm is installed on one side of the water storage tank, and an infrared temperature sensor with a measurement range of 0°C-100°C and a measurement accuracy of ±0.5°C is installed on the other side. The water storage tank is fixed on a two-axis electric displacement table by a support frame. The load-bearing capacity of the support frame is greater than 1.5 times the total weight of the water storage tank, water tank and water.

[0050] The water circulation filtration system consists of a water pump, filter, flow meter, pressure sensor, and turbidity sensor. It connects the water tank inlet and the water storage tank outlet. The filter has a filtration accuracy of 5μm and a filtration efficiency greater than 95%. The turbidity threshold is set to 5NTU. The positioning accuracy of the two-axis electric displacement stage of the water tank position adjustment mechanism is ±0.01mm for both the X and Y axes, and the repeatability is ±0.005mm. The positioning accuracy of the electric lifting stage is ±0.02mm for the Z axis, and the repeatability is ±0.01mm. The lifting speed is 1mm / s-10mm / s. The infrared proximity switch on the stage has a detection distance of 5mm-50mm and a trigger response time of less than 1ms.

[0051] The marking machine is a laser marking type with a marking accuracy of ±0.1mm. It is equipped with a cooling system, and the core of the electrical control system is a PLC controller with 36 digital input points, 18 digital output points, 10 analog input points, and 6 analog output points. The PLC scanning cycle is less than 10ms, the program storage capacity is ≥1MB, and it uses optocouplers for signal isolation with an isolation voltage greater than 2500VAC. It has an emergency stop button and a fault self-diagnosis function. The host computer is equipped with motion control software and ultrasonic testing software, supports A, B, and C real-time imaging display, and has real-time multi-channel defect alarm, defect location recording, and defect statistics functions.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An ultrasonic online testing system for continuously wound fiberglass pipes, characterized in that, The system comprises the following components: a multi-channel ultrasonic testing module, an ultrasonic probe, a water tank, a water storage tank, a water circulation and filtration system, a water tank position adjustment mechanism, a marking machine, a sound velocity dynamic calibration module, an electrical control system, and a host computer. The multi-channel ultrasonic testing module dynamically adjusts the amplitude and pulse width of the high-pressure negative square wave signal according to the pipe thickness, wherein the formula for adjusting the amplitude of the high-pressure negative square wave signal is: ,in The final output is the amplitude of the high-voltage negative square wave signal. As the reference amplitude, This is the amplitude adjustment factor. The actual thickness of the pipe to be inspected. The reference pipe thickness; The multi-channel ultrasonic detection module is connected to the ultrasonic probe and is used to generate a high-voltage negative square wave signal and receive the reflected ultrasonic signal. It converts the signal into an electrical signal and transmits it to the host computer after AD conversion. The multi-channel ultrasonic detection module integrates a pulse generator receiver and a high-speed data acquisition card and has multiple ultrasonic pulse generator and receiver channels. The ultrasonic probe: a large-size probe with low frequency of 0.2MHz or 0.5MHz is arranged along the pipeline axis at a preset interval; The water tank, fixed inside the water storage tank, is made of one or more of the following: acrylic sheet with a heat resistance exceeding 100℃, rubber elastomer, and nylon. A water inlet and a water outlet are located on one side perpendicular to the pipe axis. The tops of the two sides perpendicular to the pipe axis are arc-shaped, with hollow silicone water-blocking strips at the top of the arc surfaces. The bottom of the water tank has mounting holes for an ultrasonic probe; after fixing the probe, a sealing treatment is applied to prevent leakage. The thermal conductivity of the water tank material must meet certain requirements. The water inlet connects to the water source, and the water circulation filtration system connects to the inlet. The water flow rate can be automatically adjusted according to the tank volume and the detection rhythm. The formula for calculating the water flow rate is: ,in For water injection flow rate, For the volume of the water tank, This is a time correction factor. Duration of a single test This refers to the water injection duration; the radius of the top arc on both sides perpendicular to the pipe axis. , The compression amount of the hollow silicone water-blocking strip can be adaptively adjusted according to the pipe runout, given the outer diameter of the pipe to be tested. , The compression factor is 1. The maximum pipe runout; the ultrasonic probe mounting holes at the bottom of the water tank are sealed with silicone sealing rings to prevent leakage, and the sealing pressure must meet the requirements. ; The water storage tank is located below the water tank and has a positioning block inside. It has an ultrasonic probe wire hole at the bottom, a positioning sensor on one side, and an infrared temperature sensor on the other side. It is fixed to a two-axis electric displacement stage by a support frame. The water circulation filtration system connects the inlet of the water tank and the outlet of the water storage tank, and is used to circulate and filter the water during the testing process to achieve water recycling. The water tank position adjustment mechanism includes a support frame, a two-axis electric displacement table, an electric lifting table and a base. The support frame fixes and supports the water storage tank and the water tank and is installed on the two-axis electric displacement table. The two-axis electric displacement table is fixed on the electric lifting table surface. Both are driven by servo motors. The electric lifting table surface is equipped with an infrared proximity switch. The marking machine is used to mark the location of defects and operates after receiving a trigger signal sent by the electronic control system. The sound velocity dynamic calibration module communicates in real time with the infrared temperature sensor of the water storage tank and the multi-channel ultrasonic detection module. The sound velocity dynamic calibration module dynamically calculates and corrects the actual sound velocity of the FRP pipe material based on the actual pipe surface temperature collected by the infrared temperature sensor, the actual thickness transmitted by the pipe production equipment, and the preset material structure parameters. The corrected data is fed back to the multi-channel ultrasonic detection module in real time to adjust the ultrasonic signal excitation and reception parameters. At the same time, it updates the sound velocity reference value in the upper computer imaging algorithm to ensure the accuracy of defect location and size determination. The calibration method for the sound velocity dynamic calibration module includes the following steps: 1) Triggering conditions: When the infrared temperature sensor detects a pipe surface temperature fluctuation exceeding ±2℃, a pipe actual thickness change exceeding 5%, or the system continuously detects for 30 seconds without calibration, the sound velocity calibration is automatically triggered. 2) Data acquisition: The real-time pipe surface temperature T, actual pipe thickness δ, and preset fiberglass pipe sand layer distribution coefficient k10 are acquired from the infrared temperature sensor, with a value of 0.02-0.05, determined based on the pipe sand ratio experiment. 3) Sound speed calculation: The actual sound speed v_real is calculated using a two-factor correction formula, the formula is as follows: Where v0 is the reference sound velocity of the FRP pipe at 25℃ and reference thickness δ0, with a value of 2300m / s, k5 is the sound velocity temperature correction coefficient, with a value of 0.0015, and T0 is the reference temperature of 25℃; 4) Parameter update: The calculated v_real is transmitted to the multi-channel ultrasonic testing module in real time to adjust the ultrasonic defect signal gate range; at the same time, the distance-velocity conversion relationship of the A and B scan imaging of the host computer is updated, which avoids missing defects in the depth direction and ensures that the defect depth positioning accuracy deviation is ≤±1%; The electrical control system includes control circuits for a water circulation filtration system, a marking machine, a two-axis electric displacement table, and an electric lifting table, which are used to control the coordinated operation of each component. The host computer is equipped with motion control software and ultrasonic testing software. The ultrasonic testing software supports three real-time imaging display modes: A, B, and C. It has gate tracking settings, real-time multi-channel defect alarms, defect location recording, and defect statistics functions, and is used for signal processing, imaging display, defect judgment, and system control.

2. The ultrasonic online testing system for continuously wound fiberglass pipes according to claim 1, characterized in that, The positional accuracy of the positioning blocks inside the water storage tank must meet the following requirements. The lower ultrasonic probe's thread hole is sealed with a rubber gasket to prevent leakage; the gasket's Shore hardness is 50HA-60HA. The detection accuracy of the positioning sensor on one side must meet the following requirements. When the distance between the water tank and the pipe surface reaches a preset value, When triggered, the electric lifting platform stops moving; the infrared temperature sensor on the other side has a temperature measurement range of 0°C-100°C and a measurement accuracy of ± This is used to calibrate the sound velocity of materials; the calibration formula is: ,in The calibrated material sound velocity, As the reference speed of sound, This is the temperature correction factor for the speed of sound. The actual temperature of the pipe surface as measured by an infrared temperature sensor. The reference temperature is used; the load-bearing capacity of the support frame under the water storage tank must be greater than 1.5 times the total weight of the water storage tank, the water tank, and the water.

3. The ultrasonic online testing system for continuously wound fiberglass pipes according to claim 1, characterized in that, The water circulation filtration system includes a water pump, a filter, a flow meter, and a pressure sensor. The pump head must meet the following requirements. ,in For the water pump head, The height difference between the water tank and the storage tank. This is the pipeline resistance coefficient. The total pipeline length is ensured to guarantee sufficient water circulation power; the filter's filtration accuracy is 5μm, and the filtration efficiency must be greater than 95%. The flow meter monitors the water circulation flow rate in real time and feeds it back to the electrical control system. When the flow rate falls below a preset threshold... At this time, the electronic control system controls the water pump to increase its speed to increase the flow rate; the pressure sensor monitors the pressure of the water circulation system in real time, and when the pressure exceeds the preset maximum value... When the system automatically alarms and stops the water pump, the water circulation filtration system is also equipped with a turbidity sensor with a turbidity threshold set to 5 NTU. When the turbidity exceeds the threshold, the system prompts to replace the filter cartridge.

4. The ultrasonic online testing system for continuously wound fiberglass pipes according to claim 1, characterized in that, In the water tank position adjustment mechanism, the positioning accuracy of the X-axis of the two-axis electric displacement stage along the pipe axis and the Y-axis perpendicular to the pipe axis are both... The repeatability accuracy is The vertical positioning accuracy of the Z-axis of the electric lifting platform is: The repeatability accuracy is The lifting speed adjustment range is 1mm / s-10mm / s to meet the needs of different detection rhythms; the rated torque of the servo motors used in the two-axis electric displacement stage and electric lifting stage must meet the requirements. ,in The rated torque of the motor. The torque required to overcome the friction of the displacement stage itself, For load factor, The total load force borne by the displacement stage; the detection distance range of the infrared proximity switch on the electric lifting stage is 5mm-50mm, and the trigger response time is less than 1ms. When the pipeline moves above the sensor, it triggers the ultrasonic detection system to start working and sends a position signal to the electrical control system to ensure that each module works in coordination.

5. The ultrasonic online testing system for continuously wound fiberglass pipes according to claim 1, characterized in that, The marking machine uses an erasable inkjet marking method, with a marking accuracy of [missing information]. The marking speed is adaptively adjusted according to the pipeline movement speed. The formula for calculating the marking speed is: ,in For the marking speed of the marking machine, The speed of the pipe movement. The speed compensation coefficient is used. The marking content of the marking machine includes the size of the defect. When the host computer determines the defect, it sends a trigger signal to the marking machine through the electronic control system. The delay time of the trigger signal is less than 0.5ms. At the same time, the marking machine sends a marking completion signal back to the electronic control system.

6. The ultrasonic online testing system for continuously wound fiberglass pipes according to claim 1, characterized in that, The electrical control system uses a PLC controller as the core control unit. The signal isolation of the electrical control system adopts an optocoupler with an isolation voltage greater than 2500VAC. The electrical control system is equipped with an emergency stop button. When the system malfunctions, pressing the emergency stop button can immediately cut off the power supply to all actuators. The electrical control system also has a fault self-diagnosis function, which diagnoses sensor faults, motor faults, and communication faults, and displays the fault code and fault cause on the display screen.

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