A pressure-bearing equipment thermal insulation layer undismounting type pulse eddy current thickness measuring system and method

Abstract

The application provides a pressure-bearing equipment thermal insulation layer undismounting type pulse eddy current thickness measurement system and method, and relates to the technical field of nondestructive testing. The system comprises a probe module and a control analysis module. The probe module emits a detection pulse to the pressure-bearing equipment and receives a secondary magnetic field signal. The control analysis module extracts a quantitative space fluctuation parameter of the decay slope at the initial stage of the off period of the secondary magnetic field signal in the preceding detection period, feeds forward and scales the set pulse width of the current detection period according to the parameter; extracts the late residual amplitude at the tail end of the preceding detection period, maps the decay slope at the initial stage of the off period to a space penetration compensation coefficient, and dynamically sets the source end excitation peak value of the reverse demagnetization level by using the product of the two; and injects the reverse demagnetization level with the excitation peak value before applying the current detection pulse. The application can dynamically compensate the energy penetration dissipation caused by the space fluctuation and block the residual eddy current head-tail aliasing interference, and improve the accuracy of the equipment wall thickness inversion calculation.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, and in particular to a pulse eddy current thickness measurement system and method for non-removable insulation layers of pressure equipment. Background Technology

[0002] Pressure equipment is widely used in industrial production, and its exterior is usually covered with a thermal insulation layer. To monitor the safe operation of pressure equipment, it is necessary to periodically measure the wall thickness of its metal body. Pulse eddy current thickness measurement technology can penetrate non-ferromagnetic insulating materials, obtaining the wall thickness value of pressure equipment without damaging the thermal insulation layer.

[0003] In actual testing operations, the probe needs to continuously move and scan along the relatively rough surface of the insulation layer. The vertical spatial distance between the bottom surface of the probe and the outer surface of the pressure-bearing equipment will dynamically fluctuate accordingly. This increase in the physical lift-off gap will cause the excitation magnetic energy of the positive detection pulse to be dissipated through penetration, and will also cause the secondary magnetic field signal induced by the pressure-bearing equipment to be physically attenuated when it is transmitted upwards and back.

[0004] When performing high-frequency continuous scanning on thick-walled metal components, the induced eddy currents generated deep within the metal during the initial detection cycle have a long resistance dissipation time. When the spatial lift-off distance changes abruptly, the forward excitation magnetic energy and the reverse demagnetization magnetic energy are simultaneously lost. The physical strength of the reverse magnetic field decreases after crossing the thickened air layer, making it difficult to effectively counteract the deep-seated eddy currents. The uncounteracted residual eddy currents will overlap with the secondary magnetic field of the current detection cycle, causing a shift in the induced voltage baseline upon which the thickness inversion algorithm depends. Summary of the Invention

[0005] The purpose of this invention is to provide a non-removable pulsed eddy current thickness measurement system and method for insulation layers of pressure equipment, in order to solve the problems of magnetic energy penetration dissipation caused by dynamic fluctuations in spatial lift-off distance when the probe continuously scans along the surface of the insulation layer, and the offset of the thickness inversion baseline caused by the overlap of the head and tail of the residual eddy currents in the deep metal layer.

[0006] In a first aspect, the present invention provides a non-removable pulse eddy current thickness measurement system for the insulation layer of pressure equipment, comprising:

[0007] The probe module transmits detection pulses to the pressure equipment body and receives the secondary magnetic field signal generated by the pressure equipment body.

[0008] The control and analysis module is connected to the probe module to compensate for the secondary magnetic field signal and invert the wall thickness value.

[0009] The control and analysis module extracts the initial attenuation slope of the secondary magnetic field signal during the previous detection cycle, uses the initial attenuation slope to quantify the spatial lift-off fluctuation parameter, and feeds forward to scale the set pulse width of the detection pulse in the current detection cycle based on the spatial lift-off fluctuation parameter.

[0010] The control analysis module extracts the late residual amplitude at the end of the pre-detection cycle and maps the initial attenuation slope of the shutdown to a space penetration compensation coefficient.

[0011] The control analysis module performs a product operation using the spatial penetration compensation coefficient and the late residual amplitude to dynamically adjust the source-end excitation peak value of the reverse demagnetization level;

[0012] Before applying the detection pulse in the current detection cycle, the control and analysis module injects the reverse demagnetization level with the source end excitation peak value into the probe module.

[0013] Optionally, the control and analysis module has a built-in surface temperature detector; the surface temperature detector acquires real-time thermal values ​​at the contact position.

[0014] The control and analysis module retrieves the built-in temperature drift curve and performs differential offset correction on the induced voltage baseline of the secondary magnetic field signal by comparing it with the real-time thermistor value.

[0015] Optionally, the control analysis module extracts the logarithmic decay characteristics of the secondary magnetic field signal after differential offset correction;

[0016] The control analysis module substitutes the logarithmic decay characteristic into the metal material gain model to calculate the magnetic loss compensation coefficient, and multiplies the magnetic loss compensation coefficient with the initial thickness measurement data to output the final wall thickness value.

[0017] Optionally, a flexible, adhesive buffer layer is fixedly connected to the bottom side of the probe module;

[0018] The flexible bonding buffer layer is configured to be compressible to absorb mechanical vibrations and maintain a physical and consistent contact between the magnetic sensing element encapsulated inside the probe module and the surface of the object being measured.

[0019] Optionally, the system may also include an external visual early warning terminal;

[0020] The visualization early warning terminal receives multiple continuously generated wall thickness values ​​and stitches them together on a time axis to draw the outline of the thinning trend evolution of the pressure equipment body;

[0021] When multiple consecutive wall thickness values ​​drop to the set warning thickness threshold, the visual warning terminal triggers an audible and visual alarm and locks the three-dimensional spatial coordinates of the abnormal location.

[0022] Optionally, the control analysis module is specifically configured to extract the attenuation slope of the secondary magnetic field signal during the initial turn-off phase within the pre-detection period.

[0023] Within the aforementioned pre-detection period, starting from the point where the falling edge of the detection pulse is cut off, continuous data sampling points are extracted and a preset time is extended forward to construct an initial feature observation window.

[0024] The least squares fitting operation is performed on the multiple continuous data sampling points collected within the initial feature observation window, and the absolute value of the slope of the fitted line is extracted as the initial attenuation slope of the shutdown, which characterizes the current physical lift fluctuation trend.

[0025] Optionally, the control analysis module is specifically configured to: scale the set pulse width of the detection pulse in the current detection period based on the spatial lift-off fluctuation parameter feedforward.

[0026] Calculate the deviation between the initial attenuation slope during the shutdown and the calibrated bonding slope;

[0027] When the difference deviation indicates that the lift-off gap increases, the set pulse width of the detection pulse in the current detection cycle is extended according to the direct proportional mapping rule.

[0028] Optionally, the timing of the acquisition of the late residual amplitude is set at the end of the previous detection cycle and within the rest interval before entering the current detection cycle;

[0029] The control analysis module has a built-in spatial coupling mapping operator, which is used to monotonically map the initial attenuation slope of the shutdown to the spatial penetration compensation coefficient. The larger the initial attenuation slope of the shutdown indicates the lift-off distance, the higher the corresponding value of the spatial penetration compensation coefficient.

[0030] Optionally, the control analysis module is specifically configured to dynamically tune the source-end excitation peak value of the reverse demagnetization level by performing a product operation between the spatial penetration compensation coefficient and the late residual amplitude.

[0031] Multiply the late residual amplitude by the set damping constant to output the base demagnetizing voltage;

[0032] The final source-end excitation peak value is obtained by multiplying the basic demagnetization voltage by the space penetration compensation coefficient.

[0033] As the spatial lift-off distance increases, the peak value of the source end excitation increases synchronously, so that the reverse magnetic field energy after crossing the thickened air layer still has enough physical strength to evacuate the deep-seated eddies.

[0034] Secondly, the present invention provides a non-removable pulse eddy current thickness measurement method for insulation layers of pressure equipment, applied to the non-removable pulse eddy current thickness measurement system for insulation layers of pressure equipment as described in any one of the first aspects, comprising:

[0035] The probe module transmits detection pulses to the pressure-bearing equipment body and receives the secondary magnetic field signal induced by the pressure-bearing equipment body.

[0036] The control and analysis module compensates for the secondary magnetic field signal and inverts to obtain the wall thickness value;

[0037] The control and analysis module extracts the initial attenuation slope of the secondary magnetic field signal during the previous detection cycle, uses the initial attenuation slope to quantify the spatial lift-off fluctuation parameter, and feeds forward to scale the set pulse width of the detection pulse in the current detection cycle based on the spatial lift-off fluctuation parameter.

[0038] The control analysis module extracts the late residual amplitude at the end of the pre-detection cycle and maps the initial attenuation slope of the shutdown to a space penetration compensation coefficient.

[0039] The control analysis module performs a product operation using the spatial penetration compensation coefficient and the late residual amplitude to dynamically adjust the source-end excitation peak value of the reverse demagnetization level;

[0040] Before applying the detection pulse in the current detection cycle, the control and analysis module injects the reverse demagnetization level with the source end excitation peak value into the probe module.

[0041] The present invention has achieved the following beneficial effects:

[0042] This invention quantifies the spatial lift-off fluctuation parameter by extracting the attenuation slope of the secondary magnetic field signal at the initial turn-off stage within the pre-detection cycle. Based on this, it scales the set pulse width of the detection pulse in the current detection cycle using feedforward, and compensates for the penetration dissipation caused by the sudden increase in the physical medium air gap using additional injected positive electromagnetic energy. Simultaneously, this invention extracts the late residual amplitude at the end of the pre-detection cycle and, combined with the spatial penetration compensation coefficient derived from the attenuation slope at the initial turn-off stage, dynamically adjusts the source-end excitation peak of the reverse demagnetization level, allowing the reverse demagnetization energy to adaptively adjust to the fluctuations of the physical lift-off gap. This compensation mechanism offsets the weakening effect of the increased spatial gap on the reverse demagnetization intensity, uses a reverse magnetic field of matched strength to counteract deep-seated eddy currents, blocks the initial and final aliasing of residual eddy currents with the current induced signal, maintains the stability of the voltage baseline upon which the thickness inversion calculation depends, and improves the accuracy and data stability of the equipment wall thickness measurement results.

[0043] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a modular structure diagram of a non-removable pulse eddy current thickness measurement system for the insulation layer of pressure equipment in an embodiment of the present invention;

[0047] Figure 2 This is the main flowchart of a non-removable pulse eddy current thickness measurement method for the insulation layer of pressure equipment in an embodiment of the present invention;

[0048] Figure 3 This is a flowchart of the control logic for setting the pulse width based on the feedforward scaling of the spatial lift-off fluctuation parameter in an embodiment of the present invention.

[0049] Figure 4 This is a flowchart illustrating the calculation of the source-end excitation peak value for dynamically adjusting the reverse demagnetization level in an embodiment of the present invention.

[0050] Figure 5 This is a flowchart of the process of performing differential offset correction and inversion to obtain wall thickness values ​​in an embodiment of the present invention;

[0051] Figure 6 The control flowchart for establishing an early warning management mechanism for the visual early warning terminal in this embodiment of the invention is shown. Detailed Implementation

[0052] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0053] This application discloses a non-removable pulsed eddy current thickness measurement system and method for the insulation layer of pressure equipment. In industrial production scenarios, the exterior of pressure equipment is typically covered with a thermal insulation layer. This thermal insulation layer is usually composed of a non-conductive, non-ferromagnetic medium, and its outer surface is wrapped with a metal protective skin. The non-removable pulsed eddy current thickness measurement system for the insulation layer of pressure equipment is configured to obtain the wall thickness value of the internal pressure equipment body without damaging the aforementioned thermal insulation layer and metal protective skin.

[0054] Specifically, such as Figure 1 As shown, the non-removable pulsed eddy current thickness measurement system for the insulation layer of the pressure-bearing equipment includes a probe module and a control and analysis module. The probe module emits detection pulses to the pressure-bearing equipment body and receives the secondary magnetic field signal induced by the pressure-bearing equipment body. The control and analysis module is connected to the probe module, compensates for the secondary magnetic field signal, and inverts to obtain the wall thickness value.

[0055] Understandably, the control and analysis module incorporates a pulse generation circuit, and the probe module includes an excitation transmitting coil and a magnetic sensing element. During the detection operation, the control and analysis module, based on the set reference frequency and duty cycle parameters, controls the pulse generation circuit to output a square wave signal. After amplification, this signal forms a detection pulse, which is then injected into the excitation transmitting coil of the probe module. The detection pulse excites a primary alternating magnetic field in the space below the probe module. This primary alternating magnetic field penetrates the thermal insulation layer and the outer protective skin, transmitting to the interior of the pressure-bearing equipment body and exciting an induced eddy current field. When the control and analysis module cuts off the detection pulse, the primary alternating magnetic field collapses. The induced eddy current field inside the metal attenuates and diffuses due to resistance dissipation, radiating a secondary magnetic field signal. The magnetic sensing element inside the probe module picks up this secondary magnetic field signal, converts it into an analog induced voltage sequence, and after analog-to-digital conversion, supplies it to the control and analysis module for subsequent compensation and inversion algorithms.

[0056] During continuous scanning along the outer edge of the insulation layer of the pressure vessel, the vertical spatial distance between the bottom surface of the probe module and the outer surface of the pressure vessel exhibits dynamic fluctuations. Increased lift-off distance leads to penetration dissipation of the excitation magnetic energy of the detection pulse, and simultaneously causes attenuation of the secondary magnetic field signal during transmission. To quantify and compensate for this spatial lift-off fluctuation effect, the system performs the following steps:

[0057] Step S1: The control analysis module extracts the attenuation slope of the secondary magnetic field signal during the initial turn-off period within the pre-detection cycle, and uses the attenuation slope during the initial turn-off period to quantize the spatial extraction fluctuation parameter.

[0058] Furthermore, the control and analysis module divides the detection signal sequence into a pre-detection period and a current detection period on the time axis. The specific execution method for extracting the initial attenuation slope of the secondary magnetic field signal within the pre-detection period is as follows: starting from the cutoff point of the falling edge of the detection pulse within the pre-detection period, a preset time is extended backward to extract continuous data sampling points to construct an initial feature observation window; a least-squares fitting operation is performed on multiple continuous data sampling points collected within the initial feature observation window, and the absolute value of the slope of the fitted line is extracted as the initial attenuation slope representing the current physical lift-off fluctuation trend. The preset time extension is not an open variable subjectively specified by the software; its lower physical boundary is controlled by the self-inductance of the excitation winding inside the probe. Matching resistor with bleed The hardware first-order damped time constant is constructed. The underlying timer limits the sampling delay span to greater than or equal to... During the dead time period, the self-induced residual oscillation of the coil's back electromotive force has decayed below the hardware quantization noise floor when the analog-to-digital converter starts capturing. Simultaneously, the upper time-domain closure limit of the initial characteristic observation window is set before the critical characteristic time at which the alternating magnetic field diffuses to the skin surface of the measured metal and reflects off. Critical characteristic time Follow the formula ,in This is the minimum safe wall thickness value for the pressure vessel body, used to ensure that the observation window closes before electromagnetic waves reach the bottom wall. The absolute magnetic permeability of the material used to construct the pressure equipment. This represents the electrical conductivity of the material used in the pressure-bearing equipment. A preset time interval is added to avoid hardware-damped oscillations caused by coil inductance during pulse turn-off. After the preset time interval expires, within the constructed initial characteristic observation window, the induced eddy currents have not yet reached the metal bottom wall boundary, and the attenuation rate of the secondary magnetic field signal is mainly controlled by the spatial divergence of the magnetic circuit. The control analysis module performs a logarithmic transformation on the voltage sampling amplitude sequence within the observation window, using the sampling timestamp as the independent variable and the logarithmic voltage value as the dependent variable, to calculate a linear regression equation, and the absolute value of its slope is used as the attenuation slope at the initial turn-off stage.

[0059] Step S2: The control analysis module feeds forward and scales the set pulse width of the detection pulse in the current detection cycle according to the spatial lift-off fluctuation parameter.

[0060] Specifically, such as Figure 3 As shown, the control logic for scaling the set pulse width of the detection pulse in the current detection cycle based on the spatial lift-off fluctuation parameter feedforward includes: calculating the difference deviation between the initial attenuation slope and the calibrated fitting slope; when the difference deviation indicates that the spatial lift-off gap is increasing, extending the set pulse width of the detection pulse in the current detection cycle according to the direct proportional mapping rule.

[0061] Extract the initial attenuation slope of the current pre-detection cycle. Calculate its absolute value and the calibration bonding slope obtained when the probe is in zero-gap contact with a standard uncovered test block. The difference is used to construct a dimensionless difference deviation. The system presets a mechanical anti-shake dead zone threshold. The range of engineering values ​​is set at to Between these layers, high-frequency micro-vibrations caused by the rough surface of the insulation layer are shielded on the hardware side. When The system determines that the sliding is smooth and maintains the initially set detection pulse width. No changes will be made. The pulse width time increment is calculated by activating the first-order algebraic feedforward equation to represent the actual physical air gap dislocation and expansion. . Within the formula The electromagnetic gain coefficient of the transmitting excitation circuit is determined by the physical properties of the equivalent inductance of the probe's main winding, and is pre-calibrated within the calibration range. to The timer then reconstructs the drive duty cycle for the next detection cycle and outputs the extended target pulse width. Furthermore, the reference frequency The engineering value range is set to 2Hz to 30Hz; the initially set detection pulse width The corresponding drive duty cycle is limited to 40% to 50%.

[0062] The calibration bonding slope is a reference constant obtained by the probe module when it is bonded to the metal test block. The difference deviation characterizes the increment of the probe's current lift-off gap relative to the calibration state. When the difference deviation indicates that the spatial lift-off gap is increasing, the control analysis module calculates the pulse width time increment according to the mapping rule and adds this time increment to the duty cycle parameter, extending the conduction state of the power drive circuit, so that the probe module radiates increased electromagnetic energy to compensate for spatial physical transmission dissipation.

[0063] In the inspection of thick-walled metal components, the eddy currents excited deep within the metal during the previous detection cycle may not have fully dissipated before the start of the current detection cycle. These stagnant eddy currents can alias with the secondary magnetic field of the current detection cycle, causing a shift in the voltage baseline upon which thickness inversion depends.

[0064] Step S3: The control analysis module extracts the late residual amplitude at the end of the pre-detection cycle and maps the initial attenuation slope of the shutdown to a space penetration compensation coefficient.

[0065] Furthermore, the timing of the acquisition of the late residual amplitude is set within the rest interval at the end of the preceding detection cycle and before entering the current detection cycle. During this interval, the transmitter circuit of the probe module is disconnected. The control and analysis module intercepts the noise floor voltage sequence output by the receiving channel during this timing gap and calculates its average value as the late residual amplitude. The specific interception window for the noise floor voltage sequence is set to 50 to 100 consecutive sampling clock cycles before the rising edge of the detection pulse in the current detection cycle. Simultaneously, the control and analysis module incorporates a spatial coupling mapping operator. The control and analysis module uses this spatial coupling mapping operator to monotonically map the initial attenuation slope of the shutdown to the spatial penetration compensation coefficient. The larger the initial attenuation slope indicates the lift-off distance, the higher the corresponding spatial penetration compensation coefficient value, thus reserving a compensation margin for spatial attenuation.

[0066] Given that the effective transmission magnetic flux of a high-frequency alternating magnetic field exhibits a typical nonlinear drop with increasing physical distance when traversing non-ferromagnetic media such as air, an exponential compensation function based on the natural logarithm is employed internally in the spatial coupling mapping operator to reversely approximate this spatial dissipation phenomenon. In the formula, The base of the natural logarithm; the left side of the expression This is the generated spatial penetration compensation coefficient, an exponential constant. Characterizing the divergence curvature of magnetic flux, where The difference deviation mentioned above is used for static calibration based on the diameter of the probe housing chassis and the receiving solid angle of the magnetic sensing element. For conventional testing environments such as aluminum silicate industrial insulation cotton, the value is fixed in the range of 1.2 to 1.8.

[0067] In step S4, the control analysis module performs a product operation using the spatial penetration compensation coefficient and the late residual amplitude to dynamically adjust the source-end excitation peak value of the reverse demagnetization level.

[0068] Specifically, such as Figure 4 As shown, the step of dynamically tuning the source-end excitation peak value of the reverse demagnetization level by performing a product operation using the spatial penetration compensation coefficient and the late residual amplitude includes: multiplying the late residual amplitude by a set damping constant to output a base demagnetization voltage; and multiplying the base demagnetization voltage by the spatial penetration compensation coefficient to obtain the final source-end excitation peak value. The set damping constant is determined based on probe parameters and material conductivity parameters.

[0069] The damping constant is physically quantified to determine the impedance matching rate of the hardwired circuit at the emitter end against the deep metal charge diffusion trail. To ensure voltage dimension closure, the control analysis module invokes the relational equations. The dimensionless set damping constant is calculated. This constant maps the degree of coupling between the inherent time constant of the hardware loop and the system's detection frequency. (Within the equation) and The self-inductance and equivalent DC internal resistance of the probe excitation winding are mapped respectively. This corresponds to the current reference detection frequency of the system. The self-inductance of the probe excitation winding is also relevant. The value ranges from 2.0mH to 5.0mH, and the equivalent DC internal resistance is... The resistance is limited to 5Ω to 15Ω, and the aforementioned discharge matching resistor is 100Ω to 300Ω.

[0070] During the tuning phase, the hardware floating-point multiplier performs scalar multiplication within a preset clock cycle. ,in The preset voltage gain coefficient, The damping constant is the one calculated above. The spatial penetration compensation coefficient mapped in the previous text is used to calculate the source-end excitation peak value. In the formula This corresponds to the average value of the late residual amplitude truncated at the end of the corresponding timing sequence. Further, the voltage gain coefficient... The inherent power amplification factor of the probe's reverse drive hardware circuit is mapped, and its value is statically set by the operational amplifier feedback resistor network in the reverse demagnetization excitation circuit. To match the demagnetization energy requirements of different wall thicknesses and prevent drive overload, The engineering calibration value range is defined as between 2.0 and 5.0.

[0071] Step S5: Before applying the detection pulse in the current detection cycle, the control and analysis module injects the reverse demagnetization level with the source end excitation peak value into the probe module.

[0072] The control and analysis module injects the reverse demagnetizing level into the probe module by changing the output polarity of the drive circuit, thus establishing a reverse magnetic field. This reverse magnetic field excites a canceling current with the opposite polarity to the residual eddy current inside the metal. The two currents are vectored together, restoring the local electromagnetic state to the noise floor reference plane.

[0073] The heat transfer from pressure equipment can cause temperature drift in the parameters of the probe module and receiving circuit, resulting in a shift in the baseline of the induced voltage.

[0074] The control and analysis module has a built-in surface temperature detector; the surface temperature detector acquires real-time thermistor values ​​at the contact position; the control and analysis module retrieves the built-in temperature drift curve and performs differential offset correction on the induced voltage baseline of the secondary magnetic field signal by comparing the real-time thermistor values.

[0075] The surface temperature detector is positioned on the contact surface of the probe module. The control and analysis module uses the real-time thermistor value as the independent variable and retrieves the bias compensation voltage parameter from the temperature drift curve. Before feature inversion, the bias compensation voltage parameter is algebraically added to and subtracted from the discrete sampling points of the secondary magnetic field signal.

[0076] The temperature drift relationship curve is analyzed as a first-order linear difference algebraic expression. In the formula, The bias compensation voltage parameter, the real-time thermistor value is denoted as The ambient temperature reference during the instrument's overall assembly and calibration is recorded as: Thermosensitive correction coefficient The calibration physical range is defined as 0.5mV / ℃ to 1.2mV / ℃, comprehensively incorporating two core disturbance variables: the temperature rise and resistance expansion of the pure copper sensing winding and the junction temperature drift of the semiconductor in the pre-amplifier signal conditioning amplifier. If the original discrete induced voltage sequence output from the high-speed analog-to-digital converter is expressed as... The control analysis module's digital signal control chain will subtract the bias level point by point, outputting the purified effective sequence. ,in This is the sequence index of discrete voltage sampling points.

[0077] After completing the compensation and decoupling of the above physical parameters, the system performs wall thickness calculation, such as... Figure 5 As shown.

[0078] The control and analysis module extracts the logarithmic attenuation characteristics of the secondary magnetic field signal after differential offset correction; the control and analysis module substitutes the logarithmic attenuation characteristics into the metal material gain model to calculate the magnetic loss compensation coefficient, and multiplies the magnetic loss compensation coefficient with the initial thickness measurement data to output the final wall thickness value.

[0079] The control and analysis module extracts the late-stage long-tail segment of the signal's time-domain waveform. The starting point of this segment is defined as the time node where the amplitude of the secondary magnetic field signal decays to 5% of the peak voltage, and the ending point is the time node where the signal approaches the system's underlying quantization noise threshold. Within this segment, logarithmic operations are performed on the discrete voltage sampling amplitudes, and the slope of the decay line is calculated using linear regression, which is then determined as the logarithmic decay characteristic. Since there are physical differences in the conductivity and permeability of different grades of metal materials, the control and analysis module substitutes this logarithmic decay characteristic into the metal material gain model to calculate the magnetic loss compensation coefficient, which characterizes the differences in electromagnetic dissipation of the materials. Subsequently, this coefficient is multiplied by the initial thickness calculation data derived from the electromagnetic diffusion equation, and the final wall thickness value after material parameter calibration is output.

[0080] After the signal enters the late long-tail stage, the high-frequency skin effect basically dissipates, and its logarithmic decay characteristic absolute value... It is primarily inversely proportional to the square of the physical wall thickness of the pressure-bearing equipment. Based on the one-dimensional low-frequency electromagnetic wave diffusion law and its analytical solution characteristics, the control analysis module first calculates the initial thickness measurement data: In the formula, For initial thickness measurement data, constants These are the probe spatial geometric topology coefficients after dimensional correction. The permeability of free space, and The relative magnetic permeability and electrical conductivity of the standard carbon steel test block are used to determine the specific index. Values S / m, The value is 300, corresponding to the material designation 20# carbon inspection steel. Due to the introduction of square root calculations, this formula can accurately describe the geometric relationship between the diffusion time and thickness of electromagnetic energy deep within the metal in a physical sense. To address the nonlinear distortion of materials caused by microscopic lattice phase transitions due to different furnace numbers or long-term service in industrial settings, the metal material gain model, compared to the computationally expensive three-dimensional partial differential matrix solution, constructs a second-order parabolic polynomial. To extract the magnetic loss compensation coefficient required for correction. In the formula, the above... Represents the absolute value of the logarithmic decay characteristic. Fitting weight parameters. Based on actual measurements of an offline aging pipe sample library with real-world thickness gradients and different aging phase transformation types, least squares regression was used to extract and solidify the data in a ROM. For the aforementioned 20# carbon steel, a typical set of fitting weight parameters is as follows: The control analysis module uses final adjustment commands. Calculate the final wall thickness, where This is the final wall thickness value.

[0081] In terms of the mechanical structure fit during continuous scanning, the surface of the insulation layer has overlapping seams and protrusions such as rivets.

[0082] The probe module is fixedly connected to a flexible bonding buffer layer on its bottom side; the flexible bonding buffer layer is configured to be deformable under pressure to absorb mechanical vibration and maintain the physical continuity of contact between the magnetic sensing element encapsulated inside the probe module and the surface of the object being measured.

[0083] The flexible, bonded buffer layer utilizes micro-foamed, closed-cell polyurethane elastomer with a Shore C hardness rating between 15 and 25, naturally uncompressed with a thickness constrained between 5 and 8 millimeters. Under the conventional preload applied during continuous scanning, the buffer layer maintains a steady-state compression ratio of 30% to 40%. When the probe glides over areas of abrupt height change, such as surface overlaps, this combination of mechanical parameters can transiently provide a linear elastic restoring force of approximately 2 to 3 Newtons per millimeter, forcibly limiting the dynamic elevation fluctuations of the probe chassis within a preset tolerance range of 0.5 millimeters. Furthermore, the minute fluctuation in the electromagnetic attenuation slope corresponding to this 0.5-millimeter physical deformation limit is precisely calculated and included in the mechanical anti-shake dead zone threshold set at the bottom layer of the control and analysis module. Within.

[0084] The flexible, adhesive buffer layer is made of a foamed polymer elastic material. When the probe module encounters a protruding obstacle, the directly stressed area of ​​the flexible, adhesive buffer layer experiences localized physical yielding and elastic indentation, absorbing the mechanical impact energy. When sliding past the obstacle and entering the recessed area, the pre-compressed buffer material expands in the opposite direction to fill the physical gap. This mechanical structure effectively reduces magnetic field distortion caused by the probe's transient bounce.

[0085] To provide a clear view of pipeline measurement data and establish an early warning management mechanism, such as Figure 6 As shown:

[0086] The system also includes an external visualization early warning terminal; the visualization early warning terminal receives multiple continuously generated wall thickness values ​​and stitches them together on a time axis to draw the thinning trend evolution outline of the pressure equipment body; when multiple consecutive wall thickness values ​​drop to a set early warning thickness threshold, the visualization early warning terminal triggers an audible and visual alarm operation and locks the three-dimensional spatial coordinates of the abnormal location.

[0087] The probe module is externally rigidly mounted with a follow-up photoelectric ranging encoder wheel. The early warning terminal does not rely on uniform sampling along a single time axis; instead, it directly analyzes the physical displacement of the orthogonal pulses of the encoder wheel via hardware interrupts. It then uses cubic spline interpolation to resample the discrete inversion data in the time domain into a standard thickness measurement sequence with a fixed physical spacing. Internally, the system reconstructs the decision condition for triggering the audible and visual alarm to be depth equal to... A discrete displacement first-in-first-out (FIFO) sliding window numerical comparator (with engineering values ​​ranging from 3 to 5). It only comparators that are continuously pushed onto the stack within the sliding window. The wall thickness inversion results for adjacent spatial domains all show a value less than the preset target warning thickness. The system only determines a macroscopic thinning corrosion defect when the Boolean limit is exceeded. At the moment the alarm is triggered, the digital bus extracts the total accumulated pulse mileage and substitutes it into a pre-set pipeline space rotation matrix, unfolding and inversely solving the one-dimensional trajectory into a reference cylindrical coordinate system attached to the pressure equipment. Three-dimensional spatial anchor vector. Where, The radial coordinates (i.e. the radius of the pressure equipment body) represent the cylindrical coordinate system of the pressure equipment. Represents the circumferential angle coordinates. Represents the axial position coordinates. The rotation matrix is ​​constructed based on the constraint condition of the probe scanning along the pipeline axis in a straight line, and is set... and It is a preset constant based on the starting point position. The axis coordinates are directly mapped to the cumulative physical displacement of the encoder feedback.

[0088] The visual early warning terminal receives wall thickness values ​​and coordinate data transmitted from displacement sensors via a communication bus. It then uses an interpolation algorithm to stitch together and plot the wall thickness evolution profile curve in a two-dimensional coordinate system. The terminal is equipped with an early warning thickness threshold representing thickness tolerance. When the system determines that the wall thickness values ​​at multiple consecutive adjacent sampling points are all below this threshold, the terminal triggers an external audible and visual alarm. Simultaneously, the terminal retrieves the timestamp of the alarm and fuses it with spatial positioning data to pinpoint the three-dimensional spatial coordinates of the abnormal thinning location. This coordinates are then stored in the defect database, providing location guidance for subsequent targeted stripping and pipe section repair.

[0089] Based on the same system architecture and control flow logic, this application also discloses a non-removable pulse eddy current thickness measurement method for the insulation layer of pressure equipment, applied to the non-removable pulse eddy current thickness measurement system for the insulation layer of pressure equipment described in the above system embodiments. The method specifically includes (e.g.) Figure 2 (as shown)

[0090] The probe module transmits detection pulses to the pressure-bearing equipment body and receives the secondary magnetic field signal induced by the pressure-bearing equipment body.

[0091] The control and analysis module compensates for the secondary magnetic field signal and inverts to obtain the wall thickness value;

[0092] The control and analysis module extracts the initial attenuation slope of the secondary magnetic field signal during the previous detection cycle, uses the initial attenuation slope to quantify the spatial lift-off fluctuation parameter, and feeds forward to scale the set pulse width of the detection pulse in the current detection cycle based on the spatial lift-off fluctuation parameter.

[0093] The control analysis module extracts the late residual amplitude at the end of the pre-detection cycle and maps the initial attenuation slope of the shutdown to a space penetration compensation coefficient.

[0094] The control analysis module performs a product operation using the spatial penetration compensation coefficient and the late residual amplitude to dynamically adjust the source-end excitation peak value of the reverse demagnetization level;

[0095] Before applying the detection pulse in the current detection cycle, the control and analysis module injects the reverse demagnetization level with the source end excitation peak value into the probe module.

[0096] In its implementation, this method follows a timeline for electromagnetic thickness measurement control. The control and analysis module locks the pulse cutoff point of the preceding detection cycle, extends it forward to avoid the damped oscillation interval, and then intercepts data sampling points to calculate the initial attenuation slope. It then calculates the deviation from the calibrated fit slope. When the air gap distance increases, the pulse conduction time of the current detection cycle is extended according to the mapping rule. During the quiet interval, the system calculates the late residual amplitude and multiplies it with the monotonically mapped spatial penetration compensation coefficient and the set damping constant to obtain the source-end excitation peak value weighted by spatial transmission loss. The system injects a reverse demagnetizing level into the transmitting array by changing the conduction polarity, generating a reverse magnetic field to eliminate residual eddy current energy. Subsequently, the control and analysis module performs differential offset correction using real-time thermistor values ​​obtained from the surface temperature detector, extracts the logarithmic attenuation characteristics, and substitutes them into the metal material gain model, finally outputting the wall thickness value after material compensation. The external visualization and early warning terminal draws the outline of the thinning trend based on continuous wall thickness values, and executes an audible and visual alarm and locks the corresponding three-dimensional spatial coordinates when the data index falls below the early warning thickness threshold.

[0097] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A pulse eddy current thickness measurement system for the insulation layer of pressure-bearing equipment without removal, characterized in that, include: The probe module transmits detection pulses to the pressure equipment body and receives the secondary magnetic field signal generated by the pressure equipment body. The control and analysis module is connected to the probe module to compensate for the secondary magnetic field signal and invert the wall thickness value. The control and analysis module extracts the initial attenuation slope of the secondary magnetic field signal during the previous detection cycle, uses the initial attenuation slope to quantify the spatial lift-off fluctuation parameter, and feeds forward to scale the set pulse width of the detection pulse in the current detection cycle based on the spatial lift-off fluctuation parameter. The control analysis module extracts the late residual amplitude at the end of the pre-detection cycle and maps the initial attenuation slope of the shutdown to a space penetration compensation coefficient. The control analysis module performs a product operation using the spatial penetration compensation coefficient and the late residual amplitude to dynamically adjust the source-end excitation peak value of the reverse demagnetization level; Before applying the detection pulse in the current detection cycle, the control and analysis module injects the reverse demagnetization level with the source end excitation peak value into the probe module.

2. The non-removable pulse eddy current thickness measurement system for insulation layers of pressure-bearing equipment according to claim 1, characterized in that, The control and analysis module has a built-in surface temperature detector; the surface temperature detector acquires real-time thermal values ​​at the contact position. The control and analysis module retrieves the built-in temperature drift curve and performs differential offset correction on the induced voltage baseline of the secondary magnetic field signal by comparing it with the real-time thermistor value.

3. The non-removable pulse eddy current thickness measurement system for insulation layers of pressure-bearing equipment according to claim 2, characterized in that, The control analysis module extracts the logarithmic decay characteristics of the secondary magnetic field signal after differential offset correction; The control analysis module substitutes the logarithmic decay characteristic into the metal material gain model to calculate the magnetic loss compensation coefficient, and multiplies the magnetic loss compensation coefficient with the initial thickness measurement data to output the final wall thickness value.

4. The non-removable pulse eddy current thickness measurement system for insulation layers of pressure-bearing equipment according to claim 1, characterized in that, The probe module is fixedly connected to a flexible, adhesive buffer layer on its bottom side. The flexible bonding buffer layer is configured to be compressible to absorb mechanical vibrations and maintain a physical and consistent contact between the magnetic sensing element encapsulated inside the probe module and the surface of the object being measured.

5. The non-removable pulse eddy current thickness measurement system for insulation layers of pressure-bearing equipment according to claim 1, characterized in that, The system also includes an external visual early warning terminal; The visualization early warning terminal receives multiple continuously generated wall thickness values ​​and stitches them together on a time axis to draw the outline of the thinning trend evolution of the pressure equipment body; When multiple consecutive wall thickness values ​​drop to the set warning thickness threshold, the visual warning terminal triggers an audible and visual alarm and locks the three-dimensional spatial coordinates of the abnormal location.

6. The non-removable pulse eddy current thickness measurement system for insulation layers of pressure-bearing equipment according to claim 1, characterized in that, The control and analysis module is specifically configured to extract the attenuation slope of the secondary magnetic field signal during the initial turn-off phase within the pre-detection period. Within the aforementioned pre-detection period, starting from the point where the falling edge of the detection pulse is cut off, continuous data sampling points are extracted and a preset time is extended forward to construct an initial feature observation window. The least squares fitting operation is performed on the multiple continuous data sampling points collected within the initial feature observation window, and the absolute value of the slope of the fitted line is extracted as the initial attenuation slope of the shutdown, which characterizes the current physical lift fluctuation trend.

7. The non-removable pulse eddy current thickness measurement system for insulation layers of pressure-bearing equipment according to claim 1, characterized in that, The control analysis module is specifically configured to: scale the set pulse width of the detection pulse in the current detection period based on the spatial lift-off fluctuation parameter feedforward. Calculate the deviation between the initial attenuation slope during the shutdown and the calibrated bonding slope; When the difference deviation indicates that the lift-off gap increases, the set pulse width of the detection pulse in the current detection cycle is extended according to the direct proportional mapping rule.

8. The non-removable pulse eddy current thickness measurement system for insulation layers of pressure-bearing equipment according to claim 1, characterized in that, The timing of the acquisition of the late residual amplitude is set at the end of the previous detection cycle and within the rest interval before entering the current detection cycle; The control analysis module has a built-in spatial coupling mapping operator, which is used to monotonically map the initial attenuation slope of the shutdown to the spatial penetration compensation coefficient. The larger the initial attenuation slope of the shutdown indicates the lift-off distance, the higher the corresponding value of the spatial penetration compensation coefficient.

9. The non-removable pulse eddy current thickness measurement system for insulation layers of pressure-bearing equipment according to claim 8, characterized in that, The control and analysis module is specifically configured to dynamically tune the source-end excitation peak value by performing a product operation between the spatial penetration compensation coefficient and the late residual amplitude to dynamically adjust the reverse demagnetization level. Multiply the late residual amplitude by the set damping constant to output the base demagnetizing voltage; The final source-end excitation peak value is obtained by multiplying the basic demagnetization voltage by the space penetration compensation coefficient. As the spatial lift-off distance increases, the peak value of the source end excitation increases synchronously, so that the reverse magnetic field energy after crossing the thickened air layer still has enough physical strength to evacuate the deep-seated eddies.

10. A non-removable pulse eddy current thickness measurement method for insulation layers of pressure-bearing equipment, applied to the non-removable pulse eddy current thickness measurement system for insulation layers of pressure-bearing equipment according to any one of claims 1 to 9, characterized in that, include: The probe module transmits detection pulses to the pressure-bearing equipment body and receives the secondary magnetic field signal induced by the pressure-bearing equipment body. The control and analysis module compensates for the secondary magnetic field signal and inverts to obtain the wall thickness value; The control and analysis module extracts the initial attenuation slope of the secondary magnetic field signal during the previous detection cycle, uses the initial attenuation slope to quantify the spatial lift-off fluctuation parameter, and feeds forward to scale the set pulse width of the detection pulse in the current detection cycle based on the spatial lift-off fluctuation parameter. The control analysis module extracts the late residual amplitude at the end of the pre-detection cycle and maps the initial attenuation slope of the shutdown to a space penetration compensation coefficient. The control analysis module performs a product operation using the spatial penetration compensation coefficient and the late residual amplitude to dynamically adjust the source-end excitation peak value of the reverse demagnetization level; Before applying the detection pulse in the current detection cycle, the control and analysis module injects the reverse demagnetization level with the source end excitation peak value into the probe module.

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