Boiler inner wall crack detection method based on laser ultrasonic wave and infrared thermal imaging technology

Abstract

The invention discloses a boiler inner wall crack detection method based on a laser ultrasonic wave and infrared thermal imaging technology. The method comprises the following steps: checking detection equipment; cleaning the inner wall of the boiler; performing preliminary visual inspection on the inner wall of the boiler; laser ultrasonic detection equipment is arranged on the inner wall of the boiler; systematically performing laser ultrasonic scanning on the inner wall of the boiler; an infrared thermal imaging camera is used for scanning the inner wall of the boiler; performing infrared thermal imaging scanning; comparing and analyzing the data; and compiling a detailed detection report. According to the invention, the laser ultrasonic detection technology can detect deep micro cracks on the inner wall of the boiler with high precision, even the micro cracks can be found before the micro cracks become significant problems, and the infrared thermal imaging technology can provide visual information about crack positions and sizes by capturing thermogram differences of crack areas, so that the accuracy of the thermal imaging is improved. This technique is particularly suited for the discovery of surface cracks and for the assessment of the scope of crack impact.

Description

Technical Field

[0001] The invention relates to the field of boiler inner wall detection, and in particular to a boiler inner wall crack detection method based on laser ultrasonic and infrared thermal imaging technology. Background Art

[0002] Detection of cracks on the inner wall of a boiler is a critical maintenance task aimed at ensuring safe, reliable and efficient operation of the boiler. Since the boiler operates for a long time under high temperature and high pressure, its inner wall is often subjected to great thermal and mechanical stress, so it is easy to crack. If these cracks are not discovered and handled in time, they may cause serious equipment failures or even safety accidents.

[0003] Traditional methods for detecting cracks on the inner wall of a boiler usually rely on manual visual inspection and some basic instrumental inspections. These methods have some significant defects. Manual inspection relies on the experience and judgment of the inspectors and is easily affected by human factors, such as fatigue and distraction. In addition, it is difficult for the human eye to identify tiny cracks or internal defects. Inspection of the inner wall of a boiler, especially in narrow or high-temperature areas, can be very difficult and dangerous for inspectors.

[0004] Traditional methods are usually time-consuming and require boiler shutdown and cooling, which affects production efficiency. The accuracy and consistency of manual inspection are often limited by the inspector's skills and experience. Traditional methods usually make it difficult to accurately measure the depth and severity of cracks. Summary of the invention

[0005] The purpose of the present invention is to provide a method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology comprises the following steps:

[0008] Step S1, preparation and safety check: before starting, ensure that the boiler has been shut down and cooled to a safe temperature, check the detection equipment to ensure that it is working properly, and ensure that all operators understand the safety procedures and wear appropriate personal protective equipment;

[0009] Step S2, cleaning the boiler surface: cleaning the inner wall of the boiler to remove dust, oil stains and other impurities that affect the detection accuracy. Cleaning the boiler is essential for obtaining clear infrared images and accurate ultrasonic data;

[0010] Step S3, preliminary visual inspection: Conduct a preliminary visual inspection of the boiler inner wall to identify any obvious cracks or damage, which helps to determine the key inspection areas;

[0011] Step S4, deploying laser ultrasonic detection equipment: installing laser ultrasonic detection equipment on the inner wall of the boiler, the equipment can transmit and receive ultrasonic waves without contacting the surface, and is used to detect internal defects;

[0012] Step S5, laser ultrasonic scanning: systematically performing laser ultrasonic scanning on the inner wall of the boiler, the ultrasonic data will show the change of material density, thereby revealing cracks or other internal defects;

[0013] Step S6, deploying an infrared thermal imaging camera: using an infrared thermal imaging camera to scan the inner wall of the boiler, the camera can detect subtle changes in heat energy distribution, and cracks or damaged areas will show different thermal patterns;

[0014] Step S7, performing infrared thermal imaging scanning: after the laser ultrasonic detection, performing infrared thermal imaging scanning, focusing on the potential problem areas identified in the previous ultrasonic detection;

[0015] Step S8, data analysis: Compare and analyze the data from laser ultrasonic and infrared thermal imaging, and use software to process the data to identify and locate cracks, which can help analyze the size, shape, and possible development trend of the cracks;

[0016] Step S9, Report and Follow-up Action: Prepare a detailed inspection report, including the location, size and severity of the cracks, and formulate a corresponding repair plan or take other necessary measures based on the inspection results.

[0017] Furthermore, in step S1, the preparation and safety check are to ensure the safety of personnel and the accuracy of equipment during the detection process, the boiler is shut down and cooled to a safe temperature to prevent dangers caused by high temperature, and the equipment inspection ensures the normal operation of the detection equipment to avoid erroneous data caused by equipment failure.

[0018] Furthermore, in step S2, the boiler surface is cleaned to remove dust and impurities that may interfere with the detection signal. These impurities may affect the performance of the laser ultrasonic and infrared thermal imaging equipment, resulting in inaccurate detection results.

[0019] Furthermore, in step S3, the human eye is sensitive to large and obvious cracks, and a preliminary visual inspection can quickly identify areas that require special attention, which helps to optimize subsequent more advanced technical inspections and make them more targeted.

[0020] Furthermore, in step S4, the laser ultrasonic detection equipment detects defects inside the material by emitting ultrasonic waves and receiving their reflected waves. The ultrasonic waves generated by the laser can penetrate the material and generate reflected waves when encountering crack defects. By analyzing these reflected waves, the existence of cracks can be detected.

[0021] The formula for calculating the sound wave propagation time is as follows:

[0022] (t=\frac{d}{v})

[0023] Among them, in laser ultrasonic testing, by calculating the time t for the sound wave to propagate in the material, the distance d for the sound wave to propagate can be estimated, where v is the propagation speed of the sound wave in the material.

[0024] Furthermore, in step S5, by moving the laser ultrasonic device on the inner wall of the boiler, the entire surface can be systematically scanned, and the data collected by the device reflects the changes in the internal structure of the material, thereby revealing the location of cracks or other defects;

[0025] The formula for the law of sound wave reflection is as follows:

[0026] (\thetai=\thetar)

[0027] Among them, when the sound wave encounters a crack or interface, the incident angle thetai is equal to the reflection angle thetar, which helps to determine the path of the sound wave and thus identify the internal structure.

[0028] Furthermore, in step S6, the infrared thermal imaging camera constructs a thermal map by capturing infrared radiation on the surface of the object, and cracks or damaged areas usually display different patterns on the thermal map due to differences in heat conduction;

[0029] The Stefan-Boltzmann law is as follows:

[0030] (P=\sigma AT^4)

[0031] Among them, this formula is used to calculate the total radiation power P of the object surface, sigma is the Stefan-Boltzmann constant, A is the radiation area, and T is the absolute temperature of the object surface.

[0032] Furthermore, in step S7, after the laser ultrasonic scanning, the infrared thermal imaging scanning can provide additional information, and the scanning focuses on the slight changes in the surface temperature to help identify the heat propagation anomaly caused by the crack;

[0033] The thermal conductivity equation is as follows:

[0034] (q=-k\nabla T)

[0035] Among them, q is used to calculate the heat flow through the material, k is the thermal conductivity of the material, nabla T is the temperature gradient, and cracks will affect the heat flow path and cause changes in the temperature gradient.

[0036] Furthermore, in step S8, by comparing and analyzing the laser ultrasonic and infrared thermal imaging data, cracks can be identified more accurately, and the software can process a large amount of data to assist in identifying the specific location, size and shape of the cracks;

[0037] The data regression analysis formula is as follows:

[0038] (y=ax+b)

[0039] Among them, when processing data, linear regression can be used to analyze the relationship between data, y and x are the dependent variable and independent variable respectively, and a and b are the regression coefficients;

[0040] The error analysis formula is as follows:

[0041] (\text{error}=\text{actual value}-\text{predicted value})

[0042] Among them, the error analysis formula is used to evaluate the accuracy of the test results and calculate the difference between the actual value and the value predicted by the equipment or algorithm.

[0043] Furthermore, in step S9, the collected data and analysis results are compiled into a report, which not only indicates the location and severity of the cracks, but also provides suggestions for maintenance and preventive measures.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. The laser ultrasonic detection technology in the present invention can detect tiny cracks deep inside the boiler wall with high precision, even before they become significant problems. The sensitivity of this technology makes it particularly effective in identifying cracks at an early stage. The infrared thermal imaging technology can provide visual information about the location and size of the crack by capturing the difference in thermal images of the crack area. This technology is particularly suitable for discovering surface cracks and assessing the scope of crack impact.

[0046] 2. The present invention uses a combination of these two technologies to promptly detect and repair potential cracks, thereby greatly reducing the risk of serious failures or accidents during boiler operation. Timely repairs and maintenance help ensure the stable operation of the boiler and the safety of operators. It also allows detection without interfering with the normal operation of the boiler, thereby improving the safety of the detection process.

[0047] 3. The present invention uses these non-destructive testing technologies to perform testing without disassembling or stopping the boiler, which reduces downtime and related costs. Early detection and repair of cracks can prevent the problem from expanding, thereby saving more expensive repair costs and possible operating losses. Timely maintenance also extends the service life of the boiler, further reducing long-term maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The present invention is a schematic flow chart of a method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] See also Figure 1 , the present invention provides a technical solution:

[0051] A method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology comprises the following steps:

[0052] Step S1, preparation and safety check: before starting, ensure that the boiler has been shut down and cooled to a safe temperature, check the detection equipment to ensure that it is working properly, and ensure that all operators understand the safety procedures and wear appropriate personal protective equipment;

[0053] In this embodiment, preparation and safety checks are to ensure the safety of personnel and the accuracy of equipment during the detection process, the boiler is shut down and cooled to a safe temperature to prevent dangers caused by high temperature, and the equipment inspection ensures the normal operation of the detection equipment to avoid erroneous data caused by equipment failure.

[0054] Step S2, cleaning the boiler surface: cleaning the inner wall of the boiler to remove dust, oil stains and other impurities that affect the detection accuracy. Cleaning the boiler is essential for obtaining clear infrared images and accurate ultrasonic data;

[0055] In this embodiment, the purpose of cleaning the boiler surface is to remove dust and impurities that may interfere with the detection signal. These impurities will affect the performance of the laser ultrasonic and infrared thermal imaging equipment, resulting in inaccurate detection results.

[0056] Step S3, preliminary visual inspection: Conduct a preliminary visual inspection of the boiler inner wall to identify any obvious cracks or damage, which helps to determine the key inspection areas;

[0057] In this embodiment, the human eye is sensitive to large and obvious cracks, and the initial visual inspection can quickly identify areas that need special attention, which helps to optimize subsequent more advanced technical inspections and make them more targeted.

[0058] Step S4, deploying laser ultrasonic detection equipment: installing laser ultrasonic detection equipment on the inner wall of the boiler, the equipment can transmit and receive ultrasonic waves without contacting the surface, and is used to detect internal defects;

[0059] In this embodiment, the laser ultrasonic detection device detects defects inside the material by emitting ultrasonic waves and receiving their reflected waves. The ultrasonic waves generated by the laser can penetrate the material and generate reflected waves when encountering crack defects. By analyzing these reflected waves, the existence of cracks can be detected.

[0060] The formula for calculating the sound wave propagation time is as follows:

[0061] (t=\frac{d}{v})

[0062] Among them, in laser ultrasonic testing, by calculating the time t for the sound wave to propagate in the material, the distance d for the sound wave to propagate can be estimated, where v is the propagation speed of the sound wave in the material.

[0063] Step S5, performing laser ultrasonic scanning: systematically performing laser ultrasonic scanning on the inner wall of the boiler, the ultrasonic data will show the change of material density, thereby revealing cracks or other internal defects;

[0064] In this embodiment, by moving the laser ultrasonic device on the inner wall of the boiler, the entire surface can be systematically scanned, and the data collected by the device reflects the changes in the internal structure of the material, thereby revealing the location of cracks or other defects;

[0065] The formula for the law of sound wave reflection is as follows:

[0066] (\thetai=\thetar)

[0067] Among them, when the sound wave encounters a crack or interface, the incident angle thetai is equal to the reflection angle thetar, which helps to determine the path of the sound wave and thus identify the internal structure.

[0068] Step S6, deploying an infrared thermal imaging camera: using an infrared thermal imaging camera to scan the inner wall of the boiler, the camera can detect subtle changes in heat energy distribution, and cracks or damaged areas will show different thermal patterns;

[0069] In this embodiment, the infrared thermal imaging camera constructs a thermal map by capturing infrared radiation from the surface of an object. Cracks or damaged areas usually show different patterns on the thermal map due to differences in heat conduction.

[0070] The Stefan-Boltzmann law is as follows:

[0071] (P=\sigma AT^4)

[0072] Among them, this formula is used to calculate the total radiation power P of the object surface, sigma is the Stefan-Boltzmann constant, A is the radiation area, and T is the absolute temperature of the object surface.

[0073] Step S7, performing infrared thermal imaging scanning: after the laser ultrasonic detection, performing infrared thermal imaging scanning, focusing on the potential problem areas identified in the previous ultrasonic detection;

[0074] In this embodiment, after the laser ultrasonic scanning, the infrared thermal imaging scan can provide additional information, and the scan focuses on the small changes in surface temperature to help identify heat propagation anomalies caused by cracks;

[0075] The thermal conductivity equation is as follows:

[0076] (q=-k\nabla T)

[0077] Among them, q is used to calculate the heat flow through the material, k is the thermal conductivity of the material, nabla T is the temperature gradient, and cracks will affect the heat flow path and cause changes in the temperature gradient.

[0078] Step S8, data analysis: Compare and analyze the data from laser ultrasonic and infrared thermal imaging, and use software to process the data to identify and locate cracks, which can help analyze the size, shape, and possible development trend of the cracks;

[0079] In this embodiment, by comparing and analyzing the laser ultrasonic and infrared thermal imaging data, cracks can be identified more accurately. The software can process a large amount of data to assist in identifying the specific location, size and shape of the crack;

[0080] The data regression analysis formula is as follows:

[0081] (y=ax+b)

[0082] Among them, when processing data, linear regression can be used to analyze the relationship between data, y and x are the dependent variable and independent variable respectively, and a and b are the regression coefficients;

[0083] The error analysis formula is as follows:

[0084] (\text{error}=\text{actual value}-\text{predicted value})

[0085] Among them, the error analysis formula is used to evaluate the accuracy of the test results and calculate the difference between the actual value and the value predicted by the equipment or algorithm.

[0086] Step S9, Report and Follow-up Action: Prepare a detailed inspection report, including the location, size and severity of the cracks, and formulate a corresponding repair plan or take other necessary measures based on the inspection results;

[0087] In this embodiment, the collected data and analysis results are compiled into a report, which not only indicates the location and severity of the cracks, but also provides suggestions for repair and preventive measures.

[0088] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0089] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology, characterized in that: The following steps are involved: Step S1, preparation and safety check: before starting, ensure that the boiler has been shut down and cooled to a safe temperature, check the detection equipment to ensure that it is working properly, and ensure that all operators understand the safety procedures and wear appropriate personal protective equipment; Step S2, cleaning the boiler surface: cleaning the inner wall of the boiler to remove dust, oil stains and other impurities that affect the detection accuracy. Cleaning the boiler is essential for obtaining clear infrared images and accurate ultrasonic data; Step S3, preliminary visual inspection: Conduct a preliminary visual inspection of the boiler inner wall to identify any obvious cracks or damage, which helps to determine the key inspection areas; Step S4, deploying laser ultrasonic detection equipment: installing laser ultrasonic detection equipment on the inner wall of the boiler, the equipment can transmit and receive ultrasonic waves without contacting the surface, and is used to detect internal defects; Step S5, performing laser ultrasonic scanning: systematically performing laser ultrasonic scanning on the inner wall of the boiler, the ultrasonic data will show the change of material density, thereby revealing cracks or other internal defects; Step S6, deploying an infrared thermal imaging camera: using an infrared thermal imaging camera to scan the inner wall of the boiler, the camera can detect subtle changes in heat energy distribution, and cracks or damaged areas will show different thermal patterns; Step S7, performing infrared thermal imaging scanning: after the laser ultrasonic detection, performing infrared thermal imaging scanning, focusing on the potential problem areas identified in the previous ultrasonic detection; Step S8, data analysis: Compare and analyze the data from laser ultrasonic and infrared thermal imaging, and use software to process the data to identify and locate cracks, which can help analyze the size, shape, and possible development trend of the cracks; Step S9, Report and Follow-up Action: Prepare a detailed inspection report, including the location, size and severity of the cracks, and formulate a corresponding repair plan or take other necessary measures based on the inspection results.

2. The method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology according to claim 1 is characterized in that: In step S1, the preparation and safety check are to ensure the safety of personnel and the accuracy of equipment during the detection process, the boiler is shut down and cooled to a safe temperature to prevent dangers caused by high temperature, and the equipment inspection ensures the normal operation of the detection equipment to avoid erroneous data caused by equipment failure.

3. The method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology according to claim 1 is characterized in that: In step S2, the purpose of cleaning the boiler surface is to remove dust and impurities that may interfere with the detection signal. These impurities will affect the performance of the laser ultrasonic and infrared thermal imaging equipment, resulting in inaccurate detection results.

4. The method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology according to claim 1 is characterized in that: In step S3, the human eye is sensitive to large and obvious cracks, and the initial visual inspection can quickly identify areas that need to be focused on, which helps to optimize subsequent more advanced technical inspections and make them more targeted.

5. The method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology according to claim 1 is characterized in that: In step S4, the laser ultrasonic detection device detects defects inside the material by emitting ultrasonic waves and receiving their reflected waves. The ultrasonic waves generated by the laser can penetrate the material and generate reflected waves when encountering crack defects. By analyzing these reflected waves, the existence of cracks can be detected; The formula for calculating the sound wave propagation time is as follows: (t=\frac{d}{v}) Among them, in laser ultrasonic testing, by calculating the time t for the sound wave to propagate in the material, the distance d for the sound wave to propagate can be estimated, where v is the propagation speed of the sound wave in the material.

6. The method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology according to claim 1 is characterized in that: In step S5, by moving the laser ultrasonic device on the inner wall of the boiler, the entire surface can be systematically scanned, and the data collected by the device reflects the changes in the internal structure of the material, thereby revealing the location of cracks or other defects; The formula for the law of sound wave reflection is as follows: (\thetai=\thetar) Among them, when the sound wave encounters a crack or interface, the incident angle thetai is equal to the reflection angle thetar, which helps to determine the path of the sound wave and thus identify the internal structure.

7. The method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology according to claim 1 is characterized in that: In step S6, the infrared thermal imaging camera constructs a thermal map by capturing infrared radiation on the surface of the object. Cracks or damaged areas usually show different patterns on the thermal map due to differences in heat conduction. The Stefan-Boltzmann law is as follows: (P=\sigma AT^4) Among them, it is used to calculate the total radiation power P of the object surface, sigma is the Stefan-Boltzmann constant, A is the radiation area, and T is the absolute temperature of the object surface.

8. The method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology according to claim 1 is characterized in that: In step S7, after the laser ultrasonic scanning, the infrared thermal imaging scanning can provide additional information, and the scanning focuses on the slight changes in the surface temperature to help identify the heat propagation anomalies caused by the cracks; The thermal conductivity equation is as follows: (q=-k\nabla T) Among them, q is used to calculate the heat flow through the material, k is the thermal conductivity of the material, nabla T is the temperature gradient, and cracks will affect the heat flow path and cause changes in the temperature gradient.

9. The method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology according to claim 1 is characterized in that: In step S8, by comparing and analyzing the laser ultrasonic and infrared thermal imaging data, cracks can be identified more accurately. The software can process a large amount of data to assist in identifying the specific location, size and shape of the cracks. The data regression analysis formula is as follows: (y=ax+b) Among them, when processing data, linear regression can be used to analyze the relationship between data, y and x are the dependent variable and independent variable respectively, and a and b are the regression coefficients; The error analysis formula is as follows: (\text{error}=\text{actual value}-\text{predicted value}) Among them, the error analysis formula is used to evaluate the accuracy of the test results and calculate the difference between the actual value and the value predicted by the equipment or algorithm.

10. The method for detecting cracks on the inner wall of a boiler based on laser ultrasonic and infrared thermal imaging technology according to claim 1 is characterized in that: In step S9, the collected data and analysis results are compiled into a report, which not only indicates the location and severity of the cracks, but also provides suggestions for maintenance and preventive measures.

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