Acoustic emission online monitoring device and method for crack propagation of high-temperature pressure-bearing equipment

Abstract

The invention discloses an acoustic emission online monitoring device and method for crack propagation of high-temperature pressure-bearing equipment, and relates to the field of crack monitoring. The device comprises a waveguide rod, an acoustic emission sensor and a signal analysis module, one end of the waveguide rod is connected with the pressure-bearing equipment, and the other end of the waveguide rod is connected with the detection end of the acoustic emission sensor; the tolerable temperature of the pressure-bearing equipment is greater than a temperature threshold value; the signal output end of the acoustic emission sensor is connected with the signal input end of the signal analysis module; the waveguide rod transmits an acoustic emission signal generated by a to-be-monitored area on the pressure-bearing equipment to the acoustic emission sensor; the acoustic emission sensor converts a detected acoustic emission signal into a voltage signal; and the signal analysis module extracts acoustic emission characteristic parameters from the voltage signals, analyzes the acoustic emission characteristic parameters by adopting a trend method, and determines whether crack propagation occurs in the to-be-monitored area or not. According to the invention, extended cracks in key areas of the high-temperature pressure-bearing equipment can be monitored in real time.

Description

Technical Field

[0001] The present application relates to the field of crack monitoring, and in particular to an acoustic emission online monitoring device and method for crack propagation in high-temperature pressure-bearing equipment. Background Art

[0002] With the development of industry, high-temperature pressure equipment is increasingly used, such as hydrogenation reactors and heat exchangers in the chemical industry, and superheaters and reheater pipes of boilers in power plants in the power industry. In order to reduce heat loss, an insulation layer is generally installed on the outside of high-temperature pressure equipment. Cracks, as one of the most dangerous defects of pressure equipment, are the focus of high-temperature pressure equipment inspection. At present, the inspection of high-temperature pressure equipment is mainly carried out after the insulation layer is removed in the shutdown state. For some special cracks, such as creep type IV cracks that often appear in P91 steel welded joints, the time from generation to fracture is very fast and may occur within the inspection cycle. Therefore, it is of great significance to monitor the key areas of high-temperature pressure equipment (mainly areas prone to cracks, such as welds, elbows, tees, etc.) and promptly detect the initiation and expansion of cracks to ensure equipment safety.

[0003] At present, infrared technology is mainly used for online monitoring of cracks in high-temperature pressure-bearing equipment, but this technology is mainly suitable for the stage where penetrating cracks appear in the equipment and leakage occurs. The existing acoustic emission technology is mainly used for the detection of pressure-bearing equipment at normal temperature. On the one hand, the operating temperature of ordinary acoustic emission sensors is generally lower than 80°C, which is not suitable for high temperatures above 300°C; although high-temperature sensors can withstand high temperatures above 300°C, their sensitivity is lower than that of ordinary sensors, and their long-term stability is poor. They are only suitable for detection, not for long-term monitoring. On the other hand, the existing signal analysis and evaluation methods are mainly suitable for detection. During acoustic emission detection, the detection equipment needs to be loaded. The crack extension signal can be extracted by analyzing the signal characteristics of the sound pressure, pressure holding and pressure reduction stages. The detection process collects fewer signals, and it can ensure that there is less noise during the detection period or the noise source is known and stable. However, during monitoring, there is no loading and the noise source may change, which brings challenges to the extraction and identification of crack extension signals. Summary of the invention

[0004] The purpose of this application is to provide an acoustic emission online monitoring device and method for crack propagation in high-temperature pressure-bearing equipment, which can monitor the propagation of cracks in key areas of high-temperature pressure-bearing equipment in real time.

[0005] To achieve the above objectives, this application provides the following solutions.

[0006] In the first aspect, the present application provides an acoustic emission online monitoring device for crack extension in high-temperature pressure-bearing equipment, comprising: a waveguide rod, an acoustic emission sensor and a signal analysis module; one end of the waveguide rod is connected to the pressure-bearing equipment, and the other end of the waveguide rod is connected to the detection end of the acoustic emission sensor; the pressure-bearing equipment has a tolerance temperature greater than a temperature threshold; the signal output end of the acoustic emission sensor is connected to the signal input end of the signal analysis module; the waveguide rod is used to transmit the acoustic emission signal generated in the area to be monitored on the pressure-bearing equipment to the acoustic emission sensor; the acoustic emission sensor is used to convert the detected acoustic emission signal into a voltage signal; the signal analysis module is used to extract acoustic emission characteristic parameters from the voltage signal, and use a trend method to analyze the acoustic emission characteristic parameters to determine whether crack extension occurs in the area to be monitored.

[0007] Optionally, when the acoustic emission characteristic parameters include amplitude and energy, the signal analysis module adopts a trend method to analyze the acoustic emission characteristic parameters to determine whether crack extension occurs in the monitored area, specifically including: forming a strip chart of amplitude with time as the horizontal axis and amplitude as the vertical axis, and forming a strip chart of energy with time as the horizontal axis and energy as the vertical axis; if an amplitude change signal appears on the amplitude strip chart, and the amplitude change signal appears again after a first preset time interval, it is preliminarily determined that crack extension occurs in the monitored area; the amplitude change signal refers to a plurality of signals with amplitudes greater than or equal to an amplitude threshold that appear within a second preset time interval; the first preset time interval is greater than the second preset time interval; after preliminarily determining that crack extension occurs in the monitored area, if an energy change signal appears on the energy strip chart, and the energy change signal appears again after the first preset time interval, it is finally determined that crack extension occurs in the monitored area; the energy change signal refers to a plurality of energy mutation signals that appear within the second preset time interval.

[0008] Optionally, the waveguide rod is a cylindrical steel rod, and the diameter of the waveguide rod is greater than or equal to 10 mm; one end of the waveguide rod is processed with a groove, and the groove is connected to the pressure-bearing equipment by welding, and the distance from the welding position of the groove and the pressure-bearing equipment to the monitoring part in the monitored area on the pressure-bearing equipment is less than 2m; the other end of the waveguide rod is connected to the acoustic emission sensor by welding or threading.

[0009] Optionally, the acoustic emission online monitoring device for crack extension in high-temperature pressure-bearing equipment further includes: a ferromagnetic metal platform and a magnetic clamp; the other end of the waveguide rod is connected to the ferromagnetic metal platform, and the acoustic emission sensor is fixed on the ferromagnetic metal platform by the magnetic clamp.

[0010] Optionally, the acoustic emission online monitoring device for crack extension in high-temperature pressure-bearing equipment also includes: a preamplifier; the signal output end of the acoustic emission sensor is connected to the signal input end of the preamplifier, and the signal output end of the preamplifier is connected to the signal input end of the signal analysis module; the preamplifier is used to amplify the voltage signal and transmit it to the signal analysis module.

[0011] Optionally, the signal analysis module includes: a filter and an analysis unit; the filter is used to filter the voltage signal; the low-pass attenuation rate of the filter is greater than or equal to 120dB; the analysis unit is used to extract acoustic emission characteristic parameters from the filtered voltage signal, and use a trend method to analyze the acoustic emission characteristic parameters to determine whether crack expansion occurs in the monitored area.

[0012] Optionally, the acoustic emission online monitoring device for crack extension in high-temperature pressure-bearing equipment also includes: a signal display module; the signal display module is used to display the voltage signal and acoustic emission characteristic parameters in a list or graphical form, and display the determination result of the signal analysis module on whether crack extension has occurred in the monitored area.

[0013] In the second aspect, the present application provides an acoustic emission online monitoring method for crack extension in high-temperature pressure-bearing equipment, comprising: after the acoustic emission signal generated in the monitored area on the pressure-bearing equipment is propagated over a preset distance, the acoustic emission signal is detected by an acoustic emission sensor, and the detected acoustic emission signal is converted into a voltage signal; acoustic emission characteristic parameters are extracted from the voltage signal; and the acoustic emission characteristic parameters are analyzed using a trend method to determine whether crack extension occurs in the monitored area.

[0014] Optionally, when the acoustic emission characteristic parameters include amplitude and energy, a trend method is used to analyze the acoustic emission characteristic parameters to determine whether crack extension occurs in the monitored area, specifically including: taking time as the horizontal axis and amplitude as the vertical axis to form a strip diagram of amplitude, and taking time as the horizontal axis and energy as the vertical axis to form a strip diagram of energy; if an amplitude change signal appears on the amplitude strip diagram, and the amplitude change signal appears again after a first preset time interval, it is preliminarily determined that crack extension occurs in the monitored area; the amplitude change signal refers to a plurality of signals with amplitudes greater than or equal to an amplitude threshold that appear within a second preset time interval; the first preset time interval is greater than the second preset time interval; after preliminarily determining that crack extension occurs in the monitored area, if an energy change signal appears on the energy strip diagram, and the energy change signal appears again after the first preset time interval, it is finally determined that crack extension occurs in the monitored area; the energy change signal refers to a plurality of energy mutation signals that appear within the second preset time interval.

[0015] Optionally, a trend method is used to analyze the acoustic emission characteristic parameters to determine whether crack extension occurs in the monitored area, and then the method further includes: displaying the voltage signal and the acoustic emission characteristic parameters in a list or graphic form, and displaying the determination result of whether crack extension occurs in the monitored area.

[0016] According to the specific embodiments provided in this application, this application has the following technical effects.

[0017] The present application provides an acoustic emission online monitoring device and method for crack extension in high-temperature pressure equipment. A waveguide rod transmits the acoustic emission signal generated in the monitored area of ​​the high-temperature pressure equipment to the acoustic emission sensor. The heat dissipation of the waveguide rod can reduce the temperature of the high-temperature pressure equipment transmitted to the acoustic emission sensor, thereby solving the problem that the acoustic emission sensor cannot withstand high temperature for a long time. The signal analysis module uses a trend method to analyze the acoustic emission characteristic parameters to determine whether crack extension occurs in the monitored area, thereby realizing online monitoring of crack extension in high-temperature pressure equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic structural diagram of an acoustic emission online monitoring device for crack propagation in high-temperature pressure-bearing equipment provided in one embodiment of the present application.

[0020] Figure 2 A schematic diagram of defining simplified waveform parameters of a burst-type standard acoustic emission signal provided in another embodiment of the present application.

[0021] Figure 3 A schematic diagram of the definition of an acoustic emission impact signal provided in another embodiment of the present application.

[0022] Figure 4 A schematic diagram of the acoustic emission signal amplitude variation trend when the pressure-bearing equipment is in a stable operating state and has no crack expansion provided in one embodiment of the present application.

[0023] Figure 5 A schematic diagram of the change trend of the acoustic emission signal amplitude when the operating state of the pressure-bearing equipment changes and there is no crack extension provided in one embodiment of the present application.

[0024] Figure 6 A schematic diagram of the change trend of the acoustic emission signal amplitude when the operating state of the pressure-bearing equipment remains unchanged and cracks are expanding is provided in another embodiment of the present application.

[0025] Figure 7 A schematic flow chart of an acoustic emission online monitoring method for crack propagation in high-temperature pressure-bearing equipment provided in one embodiment of the present application.

[0026] Figure numerals: waveguide rod-1, ferromagnetic metal platform-2, acoustic emission sensor-3, magnetic clamp-4, preamplifier-5, signal analysis module-6, signal display module-7, weld-8, high-temperature pipeline-9, insulation layer-10. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0029] In an exemplary embodiment, Figure 1 As shown, an acoustic emission online monitoring device for crack extension of high-temperature pressure-bearing equipment is provided, comprising: a waveguide rod 1, an acoustic emission sensor 3 and a signal analysis module 6. One end of the waveguide rod 1 is connected to the pressure-bearing equipment, and the other end of the waveguide rod 1 is connected to the detection end of the acoustic emission sensor 3; the tolerance temperature of the pressure-bearing equipment is greater than the temperature threshold. The signal output end of the acoustic emission sensor 3 is connected to the signal input end of the signal analysis module 6. The waveguide rod 1 is used to transmit the acoustic emission signal generated in the area to be monitored on the pressure-bearing equipment to the acoustic emission sensor 3; the acoustic emission sensor 3 is used to convert the detected acoustic emission signal into a voltage signal; the signal analysis module 6 is used to extract the acoustic emission characteristic parameters from the voltage signal, and use the trend method to analyze the acoustic emission characteristic parameters to determine whether crack extension occurs in the area to be monitored.

[0030] The device of the present application can monitor key areas of high-temperature pressure-bearing equipment in real time, detect expanding cracks in time, and avoid leakage and the accidents caused by it.

[0031] As an optional embodiment, the waveguide rod 1 is a cylindrical steel rod, and the diameter of the waveguide rod 1 is greater than or equal to 10 mm. A groove is processed at one end of the waveguide rod 1, and the groove is connected to the pressure-bearing equipment by welding. The distance from the welding position of the groove and the pressure-bearing equipment to the area to be monitored on the pressure-bearing equipment is less than 2 m. The other end of the waveguide rod 1 is connected to the acoustic emission sensor 3 by welding or threading.

[0032] The material of the waveguide rod 1 can be different from that of the monitored structure, but its high temperature strength, oxidation resistance, and thermal fatigue resistance must not be lower than the performance of the material of the monitored structure. When the waveguide rod 1 reaches a certain length, the heat transfer temperature reaching the acoustic emission sensor 3 can be reduced to room temperature.

[0033] The diameter of the waveguide rod 1 is not less than 10 mm, which can effectively prevent the distortion of the acoustic emission signal. The waveguide rod 1 is connected to the area to be monitored by welding, and the welding method can ensure the integrity of the acoustic emission signal and will not cause excessive attenuation of the acoustic emission signal.

[0034] As an optional implementation, the acoustic emission online monitoring device for crack propagation of high-temperature pressure-bearing equipment further includes: a ferromagnetic metal platform 2 and a magnetic clamp 4. The other end of the waveguide rod 1 is connected to the ferromagnetic metal platform 2, and the acoustic emission sensor 3 is fixed on the ferromagnetic metal platform 2 through the magnetic clamp 4.

[0035] As an optional embodiment, the acoustic emission online monitoring device for crack extension of high-temperature pressure-bearing equipment further includes: a preamplifier 5. The signal output end of the acoustic emission sensor 3 is connected to the signal input end of the preamplifier 5, and the signal output end of the preamplifier 5 is connected to the signal input end of the signal analysis module 6. The preamplifier 5 is used to amplify the voltage signal and transmit it to the signal analysis module 6.

[0036] As an optional embodiment, the acoustic emission online monitoring device for crack extension of high-temperature pressure-bearing equipment further includes: a signal display module 7. The signal display module 7 is used to display the voltage signal and the acoustic emission characteristic parameters in a list or graphical form, and to display the determination result of the signal analysis module 6 as to whether crack extension occurs in the monitored area.

[0037] As an optional implementation, the signal analysis module 6 includes: a filter and an analysis unit. The filter is used to filter the voltage signal; the low-pass attenuation rate of the filter is greater than or equal to 120 dB. The analysis unit is used to extract acoustic emission characteristic parameters from the filtered voltage signal, and use a trend method to analyze the acoustic emission characteristic parameters to determine whether crack expansion occurs in the monitored area.

[0038] As another optional implementation, the signal analysis module 6 can also record the arrival time of the voltage signal, which can also be used as the time when the acoustic emission signal arrives at the acoustic emission sensor 3. The time when the acoustic emission signal arrives at the acoustic emission sensor 3 can also be displayed on the signal display module 7. In addition to amplitude and energy, the acoustic emission characteristic parameters extracted by the signal analysis module 6 can also include centroid frequency, main frequency, ring count, duration, rise time and RMS (Root Mean Square, effective value). By combining the acoustic emission characteristic parameters listed above, it is possible to further determine that crack extension has occurred, thereby improving the accuracy of the crack extension determination result.

[0039] The acoustic emission signal processing and analysis methods are as follows: (1) definition of acoustic emission waveform characteristic parameters, (2) list display and analysis method of acoustic emission signal parameters, and (3) single parameter analysis method of acoustic emission signals.

[0040] (1) Definition of characteristic parameters of acoustic emission waveform.

[0041] Figure 2 Simplify the definition of waveform parameters for burst standard acoustic emission signals. Figure 2 The following parameters are available: hit (event) count, ring count, energy, amplitude, duration and rise time.

[0042] For continuous acoustic emission signals, only the ring count and energy parameters in the above model are applicable. In order to more accurately describe the characteristics of continuous acoustic emission signals, the following two parameters are introduced: average signal level and effective value voltage.

[0043] The amplitude of the acoustic emission signal is usually expressed in dBae. The amplitude of the acoustic emission sensor outputting a 1μV voltage signal is defined as 0dB. The dBae amplitude of the acoustic emission signal with a voltage signal amplitude of Vae can be calculated by the following formula: dBae=20lg(Vae / 1μV).

[0044] Table 1 lists the output voltage amplitudes of acoustic emission sensors corresponding to commonly used integer amplitudes dBae.

[0045] Table 1 Sensor output voltage amplitude corresponding to commonly used integer amplitude dBae

[0046] For the actual acoustic emission signal, due to the geometric effect of the sample or the component being tested, the waveform of the acoustic emission signal is as follows: Figure 3 Therefore, for each AE channel, a series of waveform envelopes are classified into one hit or divided into different hit signals by introducing the hit definition time (HDT) of the AE signal. Figure 3 As shown in the waveform, when the HDT set by the instrument is greater than the time interval T between two wave packets passing the threshold, the two wave packets are classified as one acoustic emission impact signal; but if the HDT set by the instrument is less than the time interval T between two wave packets passing the threshold, the two wave packets are classified as two acoustic emission impact signals.

[0047] Table 2 lists the meaning and use of common acoustic emission signal characteristic parameters. The accumulation of these parameters can be defined as a function of time or test parameters (such as pressure, temperature, etc.), such as total event counts, total ring counts, and total energy counts. These parameters can also be defined as functions that change with time or test parameters, such as acoustic emission event count rate, acoustic emission ring count rate, and acoustic emission signal energy rate. Any two combinations of these parameters can also be used for correlation analysis, such as acoustic emission event-amplitude distribution, acoustic emission event energy-duration correlation diagram, etc.

[0048] Table 2 Acoustic emission signal parameters

[0049] (2) Tabulation display and analysis method of acoustic emission signal parameters.

[0050] List display is to arrange and directly display each AE signal parameter in time sequence, including signal arrival time, various AE signal parameters, external variables, coordinates of AE sources, etc. Table 3 is a list of parameter data of crack propagation AE signals collected during the pressure vessel pressurization process. When performing sensitivity measurement and simulation source positioning accuracy test on the AE system before AE detection, directly observe the data list. Data list display and analysis are also often used for accurate analysis of the intensity of AE sources.

[0051] Table 3 Parameter data list of crack propagation acoustic emission signals collected during the pressure vessel pressurization process

[0052] (3) Single parameter analysis method of acoustic emission signals.

[0053] Since early acoustic emission instruments could only obtain a few parameters such as counts, energy or amplitude, the early analysis and evaluation of acoustic emission signals usually adopted single parameter analysis methods. The most commonly used single parameter analysis methods are count analysis method, energy analysis method and amplitude analysis method.

[0054] ① Counting method.

[0055] The counting method is a common method for processing acoustic emission pulse signals. The currently used counting methods include the acoustic emission impact (or event) count rate and the ringing count rate and their total counts. There is also a counting method that weights the amplitude, called the "weighted ringing" counting method. An acoustic emission event is a single burst signal generated by a local change in the material. The acoustic emission count (ringing count) is the number of times the acoustic emission signal exceeds a certain set threshold. The number of times the signal exceeds the threshold per unit time is the count rate. The acoustic emission count rate depends on the response frequency of the sensor, the damping characteristics of the transducer, the damping characteristics of the structure and the threshold level. For an acoustic emission event, the acoustic emission count detected by the transducer is for: ; In the formula, is the center frequency of the transducer’s response, is the wave attenuation coefficient, is the peak voltage, The disadvantage of the counting method is that it is easily affected by factors such as sample geometry, sensor characteristics and connection method, threshold voltage, amplifier and filter working conditions, etc.

[0056] ②Energy analysis method.

[0057] Since the counting method has the above-mentioned disadvantages in measuring acoustic emission signals, especially for continuous acoustic emission signals, the energy of acoustic emission signals is usually measured to analyze continuous acoustic emission signals. At present, the energy measurement of acoustic emission signals is one of the main methods for quantitatively measuring acoustic emission signals. The energy of acoustic emission signals is proportional to Figure 2 The area of ​​the acoustic emission waveform is usually expressed in terms of the root mean square voltage ( ) or RMS voltage ( ) To measure the energy of the acoustic emission signal. However, most acoustic emission instruments currently use digital circuits, so the area of ​​the acoustic emission signal waveform can also be directly measured. For burst acoustic emission signals, the energy of each impact can be measured.

[0058] The mean square voltage and the root mean square voltage of a signal are defined as follows: ; ; In the formula, is the average time, is the signal voltage that changes with time. According to the theory in electronics, we can get The change over time is the energy change rate of the acoustic emission signal. Time has come Total energy in a moment It can be expressed by the following formula: .

[0059] The measurement of the energy of the acoustic emission signal can be directly related to the important physical parameters of the material (such as the mechanical energy of the emission impact, the strain rate or the deformation mechanism, etc.) without the need to establish a model of the acoustic emission signal. Energy measurement also solves the problem of measuring small-amplitude continuous acoustic emission signals. In addition, measuring the root mean square voltage or mean square voltage of the signal also has many advantages. First, and It is not very sensitive to small changes in the electronic system gain and transducer coupling, and does not depend on any threshold voltage, unlike counting technology, which is closely related to the threshold value. and It is directly related to the energy of the continuous acoustic emission signal, but for counting technology, there is no such simple relationship. and Corrections for different strain rates or different sample volumes can be easily made.

[0060] ③Amplitude analysis method.

[0061] Signal peak amplitude and amplitude distribution is a processing method that can reflect more information about the AE source. The signal amplitude is directly related to the strength of the AE source in the material, and the amplitude distribution is related to the deformation mechanism of the material. The measurement of the AE signal amplitude is also affected by factors such as the response frequency of the transducer, the damping characteristics of the transducer, the damping characteristics of the structure, and the threshold voltage level. By applying a logarithmic amplifier, accurate peak amplitude measurements can be performed on both large and small AE signals.

[0062] For the amplitude, impact and count of the acoustic emission signal, the empirical formula is obtained: ; In the formula, Indicates the accumulated ring count of the acoustic emission signal; Indicates the total number of acoustic emission signal impacts; Indicates the response frequency of the transducer; represents the fall time of the acoustic emission impact; Represents the slope parameter of the amplitude distribution.

[0063] The device of the present application is used as follows: the acoustic emission sensor 3, the preamplifier 5, the signal analysis module 6 and the signal display module 7 are connected in sequence, and the power is turned on, the signal analysis module 6 is turned on, and the acquisition parameters are set. The low-pass attenuation rate of the filter is not less than 120dB. The entire acoustic emission online monitoring device is debugged. After all parts are connected normally, background noise is collected. The threshold value is set to: maximum background noise intensity -5dB~-10dB, and monitoring begins.

[0064] The purpose of collecting background noise is that not only crack propagation will generate acoustic emission signals, but also gas flow, electronic noise, friction, etc. These signals that are not related to damage are generally called noise signals. The main purpose of collecting background noise is to check the noise level when the equipment is operating normally.

[0065] Figure 1 It is shown that the pressure-bearing equipment is a high-temperature pipeline 9, and an insulation layer 10 is arranged on the outside of the high-temperature pipeline 9. If the area to be monitored is a weld 8, and crack expansion occurs at the weld 8, the principle of the device of the present application is: crack expansion will generate stress waves, i.e., acoustic emission signals; a part of the acoustic emission signal generated by crack expansion propagates along the high-temperature pipeline 9 and the waveguide rod 1 to the ferromagnetic metal platform of the waveguide rod 1, and is detected by the acoustic emission sensor 3; the acoustic emission sensor 3 converts the detected acoustic emission signal into a voltage signal, and transmits it to the preamplifier 5; the preamplifier 5 amplifies the voltage signal and transmits it to the signal acquisition and analysis module; the signal acquisition and analysis module processes and analyzes the signal, and displays the processing and analysis results on the signal display module 7. By analyzing and displaying the results, it can be determined whether there is crack expansion in the monitored results.

[0066] As an optional implementation method, the trend method is used to analyze the monitored data, that is, by observing the change trend of the characteristic parameters of the acoustic emission signal over a period of time, it is analyzed whether there is a crack extension signal. If no crack extension occurs during the entire monitoring process, and the operating state of the pressure-bearing equipment does not change, its acoustic emission characteristic parameters such as amplitude, energy, center of mass frequency, main frequency, etc. will be displayed as a strip with a certain width over time, such as Figure 4 When the operating state changes, such as when the air flow rate changes, the change trend of the characteristic parameters of the acoustic emission signal will appear in a new trend, such as Figure 5 When cracks expand, high-amplitude signals will appear intermittently above the strip graph, such as Figure 6 As shown, the time interval between signal occurrences gradually shortens.

[0067] Therefore, when the acoustic emission characteristic parameters include amplitude and energy, the signal analysis module 6 adopts the trend method to analyze the acoustic emission characteristic parameters to determine whether there is crack expansion in the monitored area, specifically including: taking time as the horizontal axis and amplitude as the vertical axis to form a strip diagram of amplitude, and taking time as the horizontal axis and energy as the vertical axis to form a strip diagram of energy; if an amplitude change signal appears on the amplitude strip diagram, and the amplitude change signal appears again after a first preset time interval, it is preliminarily determined that crack expansion has occurred in the monitored area; the amplitude change signal refers to a plurality of signals with amplitudes greater than or equal to the amplitude threshold that appear within a second preset time interval; the first preset time interval is greater than the second preset time interval; after preliminarily determining that there is crack expansion in the monitored area, if an energy change signal appears on the energy strip diagram, and the energy change signal appears again after the first preset time interval, it is finally determined that there is crack expansion in the monitored area; the energy change signal refers to a plurality of energy mutation signals that appear within the second preset time interval.

[0068] Exemplarily, the first preset time interval is 5 hours to several days, the second preset time interval is 5 minutes, and the amplitude threshold is 75 dB. That is, when a crack is expanding, multiple signals with an amplitude not less than 75 dB will appear above the amplitude strip chart within 5 minutes, and such signals will appear again after an interval of 5 hours to several days.

[0069] The present application solves the problem that acoustic emission sensors cannot withstand high temperatures for a long time; proposes a signal analysis method (trend method) based on the trend change of acoustic emission special parameters; and can realize online monitoring of crack propagation in high-temperature pressure-bearing equipment.

[0070] Based on the same inventive concept, the embodiment of the present application also provides an acoustic emission online monitoring method for crack extension of high-temperature pressure-bearing equipment applied to the above-mentioned acoustic emission online monitoring device for crack extension of high-temperature pressure-bearing equipment. The implementation scheme for solving the problem provided by this method is similar to the implementation scheme recorded in the above-mentioned device, so the specific limitations in one or more embodiments of the acoustic emission online monitoring method for crack extension of high-temperature pressure-bearing equipment provided below can be referred to the limitations of the acoustic emission online monitoring device for crack extension of high-temperature pressure-bearing equipment above, and will not be repeated here.

[0071] In an exemplary embodiment, Figure 7 As shown, a method for online acoustic emission monitoring of crack propagation in high-temperature pressure-bearing equipment is provided, comprising the following steps 101 to 103.

[0072] Step 101: After the acoustic emission signal generated in the area to be monitored on the pressure-bearing equipment is propagated over a preset distance, the acoustic emission signal is detected by an acoustic emission sensor, and the detected acoustic emission signal is converted into a voltage signal.

[0073] Step 102: extracting acoustic emission characteristic parameters from the voltage signal.

[0074] Step 103: Analyze the acoustic emission characteristic parameters using the trend method to determine whether crack propagation occurs in the monitored area.

[0075] In another exemplary embodiment of the present application, when the acoustic emission characteristic parameters include amplitude and energy, the above step 103 can be replaced by the following steps 201 to 203.

[0076] Step 201: With time as the horizontal axis and amplitude as the vertical axis, a strip chart of amplitude is formed, and with time as the horizontal axis and energy as the vertical axis, a strip chart of energy is formed.

[0077] Step 202: If an amplitude change signal appears on the amplitude strip chart, and the amplitude change signal appears again after the first preset time interval, it is preliminarily determined that crack expansion has occurred in the monitored area; the amplitude change signal refers to a plurality of signals with amplitudes greater than or equal to the amplitude threshold appearing within the second preset time interval; the first preset time interval is greater than the second preset time interval.

[0078] Step 203: After preliminarily determining that crack extension has occurred in the monitored area, if an energy change signal appears on the energy strip diagram and the energy change signal appears again after the first preset time interval, it is finally determined that crack extension has occurred in the monitored area; the energy change signal refers to multiple energy mutation signals that appear within the second preset time interval.

[0079] In another exemplary embodiment of the present application, after the above step 103, the method may further include: displaying the voltage signal and the acoustic emission characteristic parameters in a list or graphical form, respectively, and displaying the determination result of whether crack extension occurs in the monitored area.

[0080] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An acoustic emission online monitoring device for crack propagation in high-temperature pressure-bearing equipment, characterized in that: The acoustic emission online monitoring device for crack propagation of high-temperature pressure-bearing equipment comprises: a waveguide rod, an acoustic emission sensor and a signal analysis module; One end of the waveguide rod is connected to the pressure-bearing device, and the other end of the waveguide rod is connected to the detection end of the acoustic emission sensor; the pressure-bearing device has a tolerance temperature greater than a temperature threshold; The signal output terminal of the acoustic emission sensor is connected to the signal input terminal of the signal analysis module; The waveguide rod is used to transmit the acoustic emission signal generated in the area to be monitored on the pressure-bearing equipment to the acoustic emission sensor; The acoustic emission sensor is used to convert the detected acoustic emission signal into a voltage signal; The signal analysis module is used to extract acoustic emission characteristic parameters from the voltage signal, and analyze the acoustic emission characteristic parameters using a trend method to determine whether crack propagation occurs in the area to be monitored.

2. The acoustic emission online monitoring device for crack propagation of high-temperature pressure-bearing equipment according to claim 1 is characterized in that: When the acoustic emission characteristic parameters include amplitude and energy, the signal analysis module adopts a trend method to analyze the acoustic emission characteristic parameters to determine whether crack propagation occurs in the monitored area, specifically including: With time as the horizontal axis and amplitude as the vertical axis, a strip chart of amplitude is formed, and with time as the horizontal axis and energy as the vertical axis, a strip chart of energy is formed; If an amplitude change signal appears on the amplitude strip chart, and the amplitude change signal appears again after the first preset time interval, it is preliminarily determined that crack expansion occurs in the monitored area; the amplitude change signal refers to the occurrence of multiple signals with amplitudes greater than or equal to the amplitude threshold within the second preset time interval; the first preset time interval is greater than the second preset time interval; After preliminarily determining that crack extension has occurred in the monitored area, if an energy change signal appears on the energy strip diagram and the energy change signal appears again after the first preset time interval, it is finally determined that crack extension has occurred in the monitored area; the energy change signal refers to multiple energy mutation signals that appear within the second preset time interval.

3. The acoustic emission online monitoring device for crack propagation of high-temperature pressure-bearing equipment according to claim 1 is characterized in that: The waveguide rod is a cylindrical steel rod, and the diameter of the waveguide rod is greater than or equal to 10 mm; One end of the waveguide rod is processed with a groove, and the groove is connected to the pressure-bearing equipment by welding. The distance from the welding position of the groove and the pressure-bearing equipment to the area to be monitored on the pressure-bearing equipment is less than 2m; The other end of the waveguide rod is connected to the acoustic emission sensor through welding or threading.

4. The acoustic emission online monitoring device for crack propagation in high-temperature pressure-bearing equipment according to claim 1 is characterized in that: The acoustic emission online monitoring device for crack propagation of high-temperature pressure-bearing equipment also includes: a ferromagnetic metal platform and a magnetic clamp; The other end of the waveguide rod is connected to the ferromagnetic metal platform, and the acoustic emission sensor is fixed on the ferromagnetic metal platform through a magnetic clamp.

5. The acoustic emission online monitoring device for crack propagation in high-temperature pressure-bearing equipment according to claim 1, characterized in that: The acoustic emission online monitoring device for crack extension of high-temperature pressure-bearing equipment further comprises: a preamplifier; The signal output end of the acoustic emission sensor is connected to the signal input end of the preamplifier, and the signal output end of the preamplifier is connected to the signal input end of the signal analysis module; The preamplifier is used to amplify the voltage signal and transmit it to the signal analysis module.

6. The acoustic emission online monitoring device for crack propagation in high-temperature pressure-bearing equipment according to claim 1, characterized in that: The signal analysis module includes: a filter and an analysis unit; The filter is used to filter the voltage signal; the low-pass attenuation rate of the filter is greater than or equal to 120dB; The analysis unit is used to extract acoustic emission characteristic parameters from the filtered voltage signal, and analyze the acoustic emission characteristic parameters using a trend method to determine whether crack propagation occurs in the area to be monitored.

7. The acoustic emission online monitoring device for crack propagation in high-temperature pressure-bearing equipment according to claim 1 is characterized in that: The acoustic emission online monitoring device for crack propagation of high-temperature pressure-bearing equipment further includes: a signal display module; The signal display module is used to display the voltage signal and the acoustic emission characteristic parameters in a list or graphic form, and to display the determination result of the signal analysis module as to whether crack propagation occurs in the monitored area.

8. An acoustic emission online monitoring method for crack propagation in high-temperature pressure-bearing equipment, characterized in that: The acoustic emission online monitoring method for crack propagation of high-temperature pressure-bearing equipment comprises: After the acoustic emission signal generated in the monitored area on the pressure-bearing equipment is propagated over a preset distance, the acoustic emission signal is detected by an acoustic emission sensor, and the detected acoustic emission signal is converted into a voltage signal; Extracting acoustic emission characteristic parameters from the voltage signal; The trend method is used to analyze the characteristic parameters of acoustic emission to determine whether crack propagation occurs in the monitored area.

9. The acoustic emission online monitoring method for crack propagation in high-temperature pressure-bearing equipment according to claim 8, characterized in that: When the acoustic emission characteristic parameters include amplitude and energy, the trend method is used to analyze the acoustic emission characteristic parameters to determine whether crack propagation occurs in the monitored area, specifically including: With time as the horizontal axis and amplitude as the vertical axis, a strip chart of amplitude is formed, and with time as the horizontal axis and energy as the vertical axis, a strip chart of energy is formed; If an amplitude change signal appears on the amplitude strip chart, and the amplitude change signal appears again after the first preset time interval, it is preliminarily determined that crack expansion occurs in the monitored area; the amplitude change signal refers to the occurrence of multiple signals with amplitudes greater than or equal to the amplitude threshold within the second preset time interval; the first preset time interval is greater than the second preset time interval; After preliminarily determining that crack extension has occurred in the monitored area, if an energy change signal appears on the energy strip diagram and the energy change signal appears again after the first preset time interval, it is finally determined that crack extension has occurred in the monitored area; the energy change signal refers to multiple energy mutation signals that appear within the second preset time interval.

10. The acoustic emission online monitoring method for crack propagation in high-temperature pressure-bearing equipment according to claim 8, characterized in that: The trend method is used to analyze the characteristic parameters of acoustic emission to determine whether crack propagation occurs in the monitored area, and then it also includes: The voltage signal and the acoustic emission characteristic parameters are displayed in a list or graphic form, and the determination result of whether crack propagation occurs in the monitored area is displayed.

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