Air pipe fault detection method and system

Abstract

The invention discloses an air duct fault detection method and system, and the method comprises the following steps: S1, installing a plurality of infrared thermal imagers at the outer side of a to-be-detected air duct pipeline, and the method has the beneficial effects that the heat distribution condition of the to-be-detected air duct pipeline is detected through the infrared thermal imagers, thereby facilitating the obtaining of a heat distribution image of the to-be-detected air duct pipeline, and improving the detection precision of the to-be-detected air duct pipeline; according to the method, the abnormal areas are detected, the positions of the air leakage points are identified, the air leakage amount is evaluated through the temperature changes of the positions of the air leakage points, all the air leakage points can be rapidly detected, and rapid air leakage detection work of the to-be-detected air pipeline is completed; by detecting the noise of the to-be-detected air pipeline, the vibration conditions of the pipe and the connecting parts thereof are detected after the to-be-detected air pipeline is installed, and a vibration source is searched, so that the noise of the to-be-detected air pipeline is quickly detected.

Description

Technical Field

[0001] The present invention relates to the technical field of air duct fault detection, and in particular to an air duct fault detection method and system. Background Art

[0002] The air duct is a piping system used for air transportation and distribution, usually used in air conditioning systems or ventilation and exhaust systems as a channel for air supply, return air, fresh air introduction and exhaust. The following is a detailed explanation of the air duct: 1. Classification: Classification by cross-sectional shape: Circular air duct: The resistance is the smallest, but the height dimension is the largest, and the production is relatively complex, so it is not common in actual applications; Rectangular air duct: More commonly used, relatively simple to produce, easy to install and maintain; Oblate air duct: A shape between circular and rectangular, with specific application scenarios; Classification by material: Metal air duct: Made of various metal materials, such as galvanized iron, stainless steel, etc., with good strength and durability; Composite air duct: Made of a variety of inorganic or organic materials, mostly lightweight, porous, and high thermal resistance materials, such as Durkd uct duct; polymer duct: made of polymer material, with specific physical and chemical properties, suitable for specific occasions. During the manufacturing process of the duct, sealant needs to be applied to the gaps such as the bite seam, rivet seam, flange flanging, etc. to ensure its sealing and prevent air leakage. Duct fault detection is a series of inspection, testing and diagnostic activities for the duct system, aiming to identify and solve potential problems in the duct system, but the existing duct fault detection is not comprehensive enough, the determination of duct faults is not fast enough, the duct noise is difficult to detect, and it is difficult to quickly identify the location and point of the leak when there is air leakage. Summary of the invention

[0003] The purpose of the present invention is to provide a duct fault detection method and system to solve the problems raised in the above background technology that the existing duct fault detection is not comprehensive enough, the determination of duct faults is not fast enough, the duct noise is difficult to detect, and the location and leakage point of air leakage are difficult to quickly identify.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for detecting air duct faults, comprising the following steps:

[0005] S1. Install multiple infrared thermal imagers on the outside of the air duct to be tested;

[0006] S2. Install a hot air blower on the air duct to be tested, input hot air into the air duct to be tested, and detect the air leakage of the air duct;

[0007] S3. While introducing hot air, use an infrared thermal imager to detect the heat distribution of the air duct to be tested and identify the air leakage point;

[0008] S4, performing three-dimensional laser scanning on the inside and outside of the air duct to be tested to obtain a three-dimensional scanning model of the air duct to be tested;

[0009] S5. Perform fault detection on the air duct to be tested by comparing the original design drawing with the original three-dimensional image model;

[0010] S6. Detect the air flow of the air duct to be tested, and detect the air flow resistance;

[0011] S7, performing fault detection on the connecting elbow connection of the air duct to be tested;

[0012] S8. Detect the noise of the air duct to be tested;

[0013] S9. Summarize the results of each fault detection and complete the duct fault detection work.

[0014] Preferably, the step S2 of installing a hot air blower on the air duct to be tested, inputting hot air into the air duct to be tested, and detecting and processing the air leakage of the air duct specifically includes the following steps:

[0015] S21, sending hot air to the air duct to be tested, and when the pressure in the air duct to be tested is stable, obtaining a preset hot air flow rate, and obtaining the air duct leakage value of the air duct to be tested according to the actual hot air flow rate;

[0016] S22, extracting hot air from the air duct to be measured, and when the pressure in the air duct to be measured is stable, obtaining the preset hot air extraction flow rate, and obtaining the air duct leakage value of the air duct to be measured according to the actual hot air extraction flow rate;

[0017] S23, recording the air leakage conditions of the unidirectional and reverse airflow conveying pipelines of the air duct to be tested.

[0018] Preferably, in S3, while hot air is introduced, the heat distribution of the air duct to be tested is detected by using an infrared thermal imager, and the air leakage point is identified and processed, which specifically includes the following steps:

[0019] S31, using an infrared thermal imager to scan the air duct to be tested and obtain a thermal distribution image;

[0020] S32, detecting abnormal areas in the thermal distribution image, and identifying the position of the air leakage point through the abnormal areas in the thermal distribution image;

[0021] S33, evaluating the air leakage amount by combining the temperature change of the air leakage point position in the thermal distribution image with the obtained air leakage value.

[0022] Preferably, the step of performing three-dimensional laser scanning on the inside and outside of the air duct to be measured in S4 to obtain a three-dimensional scanning model of the air duct to be measured specifically includes the following steps:

[0023] S41, fixing the position of the air duct to be measured, so that the relative position between the three-dimensional scanner and the air duct to be measured is stable;

[0024] S42, using a three-dimensional scanner to perform a three-dimensional scan on the air duct to be tested, and using the scanner to perform a comprehensive scan on the outside and inside of the air duct;

[0025] S43, pre-processing the scanned data to obtain a three-dimensional scan model of the air duct to be tested.

[0026] Preferably, the step of performing fault detection on the air duct to be tested by comparing the original design drawing with the original three-dimensional image model in S5 specifically comprises the following steps:

[0027] S51. Compare with the original design drawing or standard size to check whether the outlet pipe is deformed;

[0028] S52. Infer whether the surface has signs of cracks, peeling, or color fading by observing indirect information such as surface texture and color changes;

[0029] S53, simulating the flow of fluid in the air duct in the three-dimensional model, and detecting potential leakage points by observing the flow trajectory and velocity changes of the fluid in the model;

[0030] S54. Observe the surface details of the 3D model to assess the severity of corrosion;

[0031] S55. Identify potential blocking points by observing the fluid channels and obstacle locations in the three-dimensional model.

[0032] Preferably, the step of detecting the airflow flowability of the air duct to be tested and detecting the airflow resistance in S6 specifically includes the following steps:

[0033] S61. Set different wind speed and wind pressure conditions in the air duct and measure the air flow resistance;

[0034] S62, setting different wind speed conditions by adjusting the speed of the ventilator or the opening of the control valve, and measuring the airflow resistance after stabilizing the airflow under each wind speed condition;

[0035] S63. By adjusting the parameters of the air outlet area and the opening degree, different wind pressure conditions are set. Under each wind pressure condition, the airflow needs to be stabilized before measurement.

[0036] S64. During the measurement process, the airflow resistance data under each wind speed and wind pressure condition is recorded, and the airflow resistance is tested and processed.

[0037] Preferably, the fault detection of the connecting elbow connection of the air duct to be tested in S7 specifically includes the following steps: when detecting the elbow connection of the metal air duct, the uniformity and flatness of the weld, weld cracks, pores, and incomplete welding are detected.

[0038] Preferably, the detection of the noise of the air duct to be measured in S8 specifically includes the following steps:

[0039] S81. Set up a noise detection instrument and set up measurement points at the air inlet, air outlet and connection of the air duct to be tested;

[0040] S82. Measure the noise level under different wind speeds and working conditions and record the data;

[0041] S83, analyzing the spectrum characteristics;

[0042] S84. Use vibration sensors to measure the vibration of the air duct and its connecting parts, analyze whether the vibration data exceeds the standard, and find and process the vibration source.

[0043] Preferably, the preprocessing in S43 includes removing noise, filling holes, and splicing data from different perspectives;

[0044] The analysis of the frequency spectrum characteristics in S83 specifically includes the following steps: using a spectrum analyzer to analyze the frequency spectrum characteristics of the noise, determining the main frequency components of the noise, and judging the cause of the noise through spectrum analysis.

[0045] A duct fault detection system comprises an infrared detection module for an duct to be tested, an air leakage detection module, a 3D model building module for the duct to be tested, a 3D image module comparison module, an air flow resistance detection module, a bend connection fault detection module, and a noise detection module, wherein the output end of the infrared detection module for the duct to be tested is communicatively connected to the input end of the air leakage detection module, the output end of the air leakage detection module is communicatively connected to the input end of the 3D model building module for the duct to be tested, the output end of the 3D model building module for the duct to be tested is communicatively connected to the input end of the 3D image module comparison module, the 3D image module comparison module is bidirectionally connected to the air flow resistance detection module, the air flow resistance detection module is bidirectionally connected to the bend connection fault detection module, and the bend connection fault detection module is bidirectionally connected to the noise detection module;

[0046] The infrared detection module for the air duct to be tested is used to introduce hot air into the air duct to be tested, and detect the position of the air leakage point in the thermal distribution image;

[0047] The air leakage detection module is used to record the temperature change of the air leakage point position in the thermal distribution image and evaluate the air leakage amount;

[0048] The module for establishing the three-dimensional model of the air duct to be measured is used to scan and establish the three-dimensional model of the air duct to be measured;

[0049] The three-dimensional image module comparison module performs comparison processing by comparing the original design drawing with the original three-dimensional image model;

[0050] The airflow resistance detection module records the airflow resistance data of the air duct to be tested under each wind speed and wind pressure condition;

[0051] The elbow joint fault detection module detects weld uniformity, flatness, weld cracks, pores, and incomplete welding;

[0052] The noise detection module is used to detect the vibration data of the vibration noise and to detect and process the vibration source of the air duct to be tested.

[0053] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows: the thermal distribution of the air duct to be measured is detected by an infrared thermal imager, so that the thermal distribution image of the air duct to be measured is obtained conveniently, the abnormal area is detected, the position of the air leakage point is identified, and the air leakage amount is evaluated by the temperature change of the air leakage point position, so that each air leakage point can be detected quickly to complete the rapid air leakage detection of the air duct to be measured; by detecting the noise of the air duct to be measured, the vibration of the pipe and its connecting parts are detected after the air duct to be measured is installed, and the vibration source is found to quickly detect the noise of the air duct to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the drawings required for the implementation methods or the prior art descriptions are briefly introduced below. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0056] Figure 1 It is a schematic diagram of the steps of the method of the present invention. DETAILED DESCRIPTION

[0057] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices consistent with some aspects of the present disclosure as detailed in the appended claims.

[0058] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. 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.

[0059] See also Figure 1 As shown, a method for detecting air duct faults according to an embodiment of the present invention comprises the following steps:

[0060] S1. Install multiple infrared thermal imagers on the outside of the air duct to be tested;

[0061] S2. Install a hot air blower on the air duct to be tested, input hot air into the air duct to be tested, and detect the air leakage of the air duct;

[0062] S3. While introducing hot air, the thermal distribution of the air duct to be tested is detected by using an infrared thermal imager, and the air leakage point is identified and processed. The thermal distribution of the air duct to be tested is detected by the infrared thermal imager, which facilitates the acquisition of the thermal distribution image of the air duct to be tested, detects the abnormal area, identifies the position of the air leakage point, and evaluates the air leakage volume through the temperature change of the air leakage point position. It can quickly detect each air leakage point and complete the rapid air leakage detection work of the air duct to be tested;

[0063] S4, performing three-dimensional laser scanning on the inside and outside of the air duct to be tested to obtain a three-dimensional scanning model of the air duct to be tested;

[0064] S5. Perform fault detection on the air duct to be tested by comparing the original design drawing with the original three-dimensional image model;

[0065] S6. Detect the air flow of the air duct to be tested, and detect the air flow resistance;

[0066] S7. Perform fault detection on the elbow joints of the air duct to be tested. As an important part of the ventilation system, the stability and reliability of the elbow joints of the air duct are directly related to the normal operation of the entire system. Once a fault occurs at the joint, such as looseness, cracks or rust, it may cause air leakage, thereby affecting the ventilation efficiency and effect of the system. Potential problems should be discovered and repaired in time to ensure the stable operation of the system.

[0067] S8, detecting the noise of the air duct to be measured, detecting the vibration of the pipe and its connecting parts after installing the air duct to be measured, finding the vibration source, and thus quickly detecting the noise of the air duct to be measured;

[0068] S9. Summarize the results of each fault detection and complete the duct fault detection work.

[0069] Among them, in S2, installing a hot air blower on the air duct to be tested, inputting hot air into the air duct to be tested, and detecting and processing the air leakage of the air duct specifically includes the following steps:

[0070] S21, sending hot air to the air duct to be tested, and when the pressure in the air duct to be tested is stable, obtaining a preset hot air flow rate, and obtaining the air duct leakage value of the air duct to be tested according to the actual hot air flow rate;

[0071] S22, extracting hot air from the air duct to be measured, and when the pressure in the air duct to be measured is stable, obtaining the preset hot air extraction flow rate, and obtaining the air duct leakage value of the air duct to be measured according to the actual hot air extraction flow rate;

[0072] S23, recording the air leakage conditions of the unidirectional and reverse airflow conveying pipelines of the air duct to be tested.

[0073] Among them, in S3, while hot air is introduced, the heat distribution of the air duct to be tested is detected by using an infrared thermal imager, and the air leakage point is identified and processed, which specifically includes the following steps:

[0074] S31, using an infrared thermal imager to scan the air duct to be tested and obtain a thermal distribution image;

[0075] S32, detecting abnormal areas in the thermal distribution image, and identifying the position of the air leakage point through the abnormal areas in the thermal distribution image;

[0076] S33. The leakage volume is evaluated and processed by combining the temperature change of the leakage point in the thermal distribution image with the obtained leakage value, and the thermal distribution of the air duct to be tested is detected by an infrared thermal imager, so as to facilitate the acquisition of the thermal distribution image of the air duct to be tested, detect the abnormal area, identify the position of the leakage point, and evaluate the leakage volume by the temperature change of the leakage point. Each leakage point can be detected quickly, and the rapid leakage detection of the air duct to be tested can be completed.

[0077] Among them, in S4, the inside and outside of the air duct to be measured are subjected to three-dimensional laser scanning processing to obtain a three-dimensional scanning model of the air duct to be measured, which specifically includes the following steps:

[0078] S41, fixing the position of the air duct to be measured, so that the relative position between the three-dimensional scanner and the air duct to be measured is stable;

[0079] S42, using a three-dimensional scanner to perform a three-dimensional scan on the air duct to be tested, and using the scanner to perform a comprehensive scan on the outside and inside of the air duct;

[0080] S43, pre-processing the scanned data to obtain a three-dimensional scan model of the air duct to be tested.

[0081] Among them, the process of performing fault detection on the air duct to be tested by comparing the original design drawing with the original three-dimensional image model in S5 specifically includes the following steps:

[0082] S51. Compare with the original design drawing or standard size to check whether the outlet pipe is deformed;

[0083] S52. Infer whether the surface has signs of cracks, peeling, or color fading by observing indirect information such as surface texture and color changes;

[0084] S53, simulating the flow of fluid in the air duct in the three-dimensional model, and detecting potential leakage points by observing the flow trajectory and velocity changes of the fluid in the model;

[0085] S54. Observe the surface details of the 3D model to assess the severity of corrosion;

[0086] S55. Identify potential blocking points by observing the fluid channels and obstacle locations in the three-dimensional model.

[0087] Among them, the detection of the air flow performance of the air duct to be tested in S6 and the detection and processing of the air flow resistance specifically include the following steps:

[0088] S61. Set different wind speed and wind pressure conditions in the air duct and measure the air flow resistance;

[0089] S62, setting different wind speed conditions by adjusting the speed of the ventilator or the opening of the control valve, and measuring the airflow resistance after stabilizing the airflow under each wind speed condition;

[0090] S63. By adjusting the parameters of the air outlet area and the opening degree, different wind pressure conditions are set. Under each wind pressure condition, the airflow needs to be stabilized before measurement.

[0091] S64, during the measurement process, record the airflow resistance data under each wind speed and wind pressure condition, and perform detection processing on the airflow resistance;

[0092] Including static pressure, dynamic pressure and total pressure parameters. Excessive airflow resistance may increase the system fan load, affecting the efficiency and energy consumption of the overall system. Check the smoothness of the inner wall of the air duct. If the surface is too rough, it will increase the airflow resistance and reduce the ventilation efficiency.

[0093] Among them, the fault detection of the connecting elbow joints of the air duct to be tested in S7 specifically includes the following steps: when detecting the elbow joints of the metal air duct, the uniformity and flatness of the weld, weld cracks, pores, and incomplete welding are detected. The quality of the weld directly affects the strength and sealing of the air duct. The air duct is an important part of the ventilation system, and the stability and reliability of its connecting elbow joints are directly related to the normal operation of the entire system. Once a fault occurs in the connection, such as looseness, cracks or rust, it may cause air leakage, which in turn affects the ventilation efficiency and effect of the system. Potential problems should be discovered and repaired in a timely manner to ensure the stable operation of the system.

[0094] The detection of the noise of the air duct to be tested in S8 specifically includes the following steps:

[0095] S81. Set up a noise detection instrument and set up measurement points at the air inlet, air outlet and connection of the air duct to be tested;

[0096] S82. Measure the noise level under different wind speeds and working conditions and record the data;

[0097] S83, analyzing the spectrum characteristics;

[0098] S84. Use a vibration sensor to measure the vibration of the air duct and its connecting parts, analyze whether the vibration data exceeds the standard, find and process the vibration source, detect the noise of the air duct to be tested, detect the vibration of the pipe and its connecting parts after installing the air duct to be tested, find the vibration source, and quickly detect the noise of the air duct to be tested.

[0099] Among them, the preprocessing in S43 includes removing noise, filling holes, and splicing data from different perspectives;

[0100] The analysis of the frequency spectrum characteristics in S83 specifically includes the following steps: using a spectrum analyzer to analyze the frequency spectrum characteristics of the noise, determining the main frequency components of the noise, and judging the cause of the noise through spectrum analysis.

[0101] A duct fault detection system includes an infrared detection module for an duct to be tested, an air leakage detection module, a 3D model building module for the duct to be tested, a 3D image module comparison module, an air flow resistance detection module, a bend connection fault detection module, and a noise detection module. The output end of the infrared detection module for the duct to be tested is communicatively connected to the input end of the air leakage detection module, the output end of the air leakage detection module is communicatively connected to the input end of the 3D model building module for the duct to be tested, the output end of the 3D model building module for the duct to be tested is communicatively connected to the input end of the 3D image module comparison module, the 3D image module comparison module is bidirectionally connected to the air flow resistance detection module, the air flow resistance detection module is bidirectionally connected to the bend connection fault detection module, and the bend connection fault detection module is bidirectionally connected to the noise detection module.

[0102] The infrared detection module of the air duct to be tested is used to introduce hot air into the air duct to be tested, and detect the position of the air leakage point in the thermal distribution image;

[0103] The air leakage detection module is used to record the temperature change of the air leakage point in the thermal distribution image and evaluate the air leakage amount;

[0104] The module for establishing the three-dimensional model of the air duct to be tested is used to scan and establish the three-dimensional model of the air duct to be tested;

[0105] The three-dimensional image module comparison module performs comparison processing by comparing the original design drawing with the original three-dimensional image model;

[0106] The airflow resistance detection module records the airflow resistance data of the air duct to be tested under each wind speed and wind pressure condition;

[0107] The fault detection module for elbow joints detects weld uniformity, flatness, weld cracks, pores, and incomplete welding.

[0108] The noise detection module is used to detect the vibration data of vibration noise and to detect and process the vibration source of the air duct to be tested.

[0109] A method for detecting air duct faults comprises the following steps:

[0110] S1. Install multiple infrared thermal imagers on the outside of the air duct to be tested;

[0111] S2. Install a hot air blower on the air duct to be tested, and send hot air to the air duct to be tested. When the pressure in the air duct to be tested is stable, obtain the preset hot air supply flow rate, and obtain the air duct leakage value of the air duct to be tested according to the actual hot air supply flow rate. Extract hot air from the air duct to be tested. When the pressure in the air duct to be tested is stable, obtain the preset hot air extraction flow rate, and obtain the air duct leakage value of the air duct to be tested according to the actual hot air extraction flow rate, and record the air leakage of the unidirectional and reverse airflow of the air duct to be tested;

[0112] S3. Use an infrared thermal imager to scan the air duct to be tested, obtain a thermal distribution image, detect abnormal areas in the thermal distribution image, identify the position of the air leakage point through the abnormal area in the thermal distribution image, and evaluate the air leakage amount through the temperature change of the air leakage point position in the thermal distribution image combined with the obtained air leakage value;

[0113] S4, fix the position of the air duct to be tested, stabilize the relative position between the three-dimensional scanner and the air duct to be tested, perform three-dimensional scanning on the air duct to be tested by the three-dimensional scanner, use the scanner to perform a comprehensive scan of the outside and inside of the air duct, pre-process the scanned data to obtain a three-dimensional scanning model of the air duct to be tested, and the pre-processing includes removing noise, filling holes, and splicing data from different perspectives;

[0114] S5. Compare the original design drawing or standard size to check whether the outlet pipe is deformed. Infer whether there are signs of cracks, peeling, and color fading on the surface by observing indirect information such as surface texture and color changes. Simulate the flow of fluid in the air duct in the 3D model. Detect potential leakage points by observing the flow trajectory and velocity changes of the fluid in the model. Observe the surface details of the 3D model to evaluate the severity of rust. Identify potential blockage points by observing the fluid channels and obstacle locations in the 3D model.

[0115] S6. Set different wind speed and wind pressure conditions in the air duct to measure the airflow resistance. Set different wind speed conditions by adjusting the speed of the fan or the opening of the control valve. Under each wind speed condition, after the airflow is stabilized, measure the airflow resistance. Set different wind pressure conditions by adjusting the parameters of the air outlet area and the opening degree. Under each wind pressure condition, it is also necessary to stabilize the airflow before measuring. During the measurement process, record the airflow resistance data under each wind speed and wind pressure condition, and perform detection and processing on the airflow resistance.

[0116] S7. When inspecting the bend joints of metal ducts, inspect the uniformity and flatness of the welds, weld cracks, pores, and incomplete welding;

[0117] S8. Set up noise detection equipment, set up measuring points at the air inlet, air outlet and connection of the air duct to be tested, measure the noise level under different wind speeds and working conditions, and record the data. Use a spectrum analyzer to analyze the spectrum characteristics of the noise, determine the main frequency components of the noise, and judge the cause of the noise through spectrum analysis. Use a vibration sensor to measure the vibration of the air duct and its connecting parts, analyze whether the vibration data exceeds the standard, and find and deal with the vibration source;

[0118] S9. Summarize the results of each fault detection and complete the duct fault detection work.

[0119] 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.

[0120] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are intended to be exemplary only, and the true scope of the present disclosure is indicated by the following claims.

Claims

1. A method for detecting air duct faults, characterized in that: The following steps are involved: S1. Install multiple infrared thermal imagers on the outside of the air duct to be tested; S2. Install a hot air blower on the air duct to be tested, input hot air into the air duct to be tested, and detect the air leakage of the air duct; S3. While introducing hot air, use an infrared thermal imager to detect the heat distribution of the air duct to be tested and identify the air leakage point; S4, performing three-dimensional laser scanning on the inside and outside of the air duct to be tested to obtain a three-dimensional scanning model of the air duct to be tested; S5. Perform fault detection on the air duct to be tested by comparing the original design drawing with the original three-dimensional image model; S6. Detect the air flow of the air duct to be tested, and detect the air flow resistance; S7, performing fault detection on the connecting elbow connection of the air duct to be tested; S8. Detect the noise of the air duct to be tested; S9. Summarize the results of each fault detection and complete the duct fault detection work.

2. A method for detecting air duct faults according to claim 1, characterized in that: The step S2 of installing a hot air blower on the air duct to be tested, inputting hot air into the air duct to be tested, and detecting and processing the air leakage of the air duct specifically includes the following steps: S21, sending hot air to the air duct to be tested, and when the pressure in the air duct to be tested is stable, obtaining a preset hot air flow rate, and obtaining the air duct leakage value of the air duct to be tested according to the actual hot air flow rate; S22, extracting hot air from the air duct to be measured, and when the pressure in the air duct to be measured is stable, obtaining the preset hot air extraction flow rate, and obtaining the air duct leakage value of the air duct to be measured according to the actual hot air extraction flow rate; S23, recording the air leakage conditions of the unidirectional and reverse airflow conveying pipelines of the air duct to be tested.

3. A method for detecting air duct faults according to claim 2, characterized in that: In S3, while hot air is introduced, the heat distribution of the air duct to be tested is detected by using an infrared thermal imager, and the air leakage point is identified and processed, which specifically includes the following steps: S31, using an infrared thermal imager to scan the air duct to be tested and obtain a thermal distribution image; S32, detecting abnormal areas in the thermal distribution image, and identifying the position of the air leakage point through the abnormal areas in the thermal distribution image; S33, evaluating the air leakage amount by combining the temperature change of the air leakage point position in the thermal distribution image with the obtained air leakage value.

4. A method for detecting air duct faults according to claim 3, characterized in that: The step S4 of performing three-dimensional laser scanning on the inside and outside of the air duct to be measured to obtain a three-dimensional scanning model of the air duct to be measured specifically includes the following steps: S41, fixing the position of the air duct to be measured, so that the relative position between the three-dimensional scanner and the air duct to be measured is stable; S42, using a three-dimensional scanner to perform a three-dimensional scan on the air duct to be tested, and using the scanner to perform a comprehensive scan on the outside and inside of the air duct; S43, pre-processing the scanned data to obtain a three-dimensional scan model of the air duct to be tested.

5. A method for detecting air duct faults according to claim 4, characterized in that: The fault detection process of the air duct to be tested by comparing the original design drawing with the original three-dimensional image model in S5 specifically includes the following steps: S51. Compare with the original design drawing or standard size to check whether the outlet pipe is deformed; S52. Infer whether the surface has signs of cracks, peeling, or color fading by observing indirect information such as surface texture and color changes; S53, simulating the flow of fluid in the air duct in the three-dimensional model, and detecting potential leakage points by observing the flow trajectory and velocity changes of the fluid in the model; S54. Observe the surface details of the 3D model to assess the severity of corrosion; S55. Identify potential blocking points by observing the fluid channels and obstacle locations in the three-dimensional model.

6. A method for detecting air duct faults according to claim 5, characterized in that: The step S6 of detecting the air flow of the air duct to be tested and detecting the air flow resistance specifically includes the following steps: S61. Set different wind speed and wind pressure conditions in the air duct and measure the air flow resistance; S62, setting different wind speed conditions by adjusting the speed of the ventilator or the opening of the control valve, and measuring the airflow resistance after stabilizing the airflow under each wind speed condition; S63. By adjusting the parameters of the air outlet area and the opening degree, different wind pressure conditions are set. Under each wind pressure condition, the airflow needs to be stabilized before measurement. S64. During the measurement process, the airflow resistance data under each wind speed and wind pressure condition is recorded, and the airflow resistance is tested and processed.

7. A method for detecting air duct faults according to claim 6, characterized in that: The fault detection of the connecting elbow connection of the air duct to be tested in S7 specifically includes the following steps: when detecting the elbow connection of the metal air duct, the uniformity and flatness of the weld, weld cracks, pores, and incomplete welding are detected.

8. A method for detecting air duct faults according to claim 7, characterized in that: The detection of the noise of the air duct to be measured in S8 specifically includes the following steps: S81. Set up a noise detection instrument and set up measurement points at the air inlet, air outlet and connection of the air duct to be tested; S82. Measure the noise level under different wind speeds and working conditions and record the data; S83, analyzing the spectrum characteristics; S84. Use vibration sensors to measure the vibration of the air duct and its connecting parts, analyze whether the vibration data exceeds the standard, and find and process the vibration source.

9. A method for detecting air duct faults according to claim 8, characterized in that: The preprocessing in S43 includes removing noise, filling holes, and splicing data from different perspectives; The analysis of the frequency spectrum characteristics in S83 specifically includes the following steps: using a spectrum analyzer to analyze the frequency spectrum characteristics of the noise, determining the main frequency components of the noise, and judging the cause of the noise through spectrum analysis.

10. A duct fault detection system, characterized in that: It includes an infrared detection module for the air duct to be tested, an air leakage detection module, a three-dimensional model building module for the air duct to be tested, a three-dimensional image module comparison module, an air flow resistance detection module, a bend connection fault detection module, and a noise detection module. The output end of the infrared detection module for the air duct to be tested is communicatively connected to the input end of the air leakage detection module, the output end of the air leakage detection module is communicatively connected to the input end of the three-dimensional model building module for the air duct to be tested, the output end of the three-dimensional model building module for the air duct to be tested is communicatively connected to the input end of the three-dimensional image module comparison module, the three-dimensional image module comparison module is bidirectionally connected to the air flow resistance detection module, the air flow resistance detection module is bidirectionally connected to the bend connection fault detection module, and the bend connection fault detection module is bidirectionally connected to the noise detection module; The infrared detection module for the air duct to be tested is used to introduce hot air into the air duct to be tested, and detect the position of the air leakage point in the thermal distribution image; The air leakage detection module is used to record the temperature change of the air leakage point position in the thermal distribution image and evaluate the air leakage amount; The module for establishing the three-dimensional model of the air duct to be measured is used to scan and establish the three-dimensional model of the air duct to be measured; The three-dimensional image module comparison module performs comparison processing by comparing the original design drawing with the original three-dimensional image model; The airflow resistance detection module records the airflow resistance data of the air duct to be tested under each wind speed and wind pressure condition; The elbow joint fault detection module detects weld uniformity, flatness, weld cracks, pores, and incomplete welding; The noise detection module is used to detect the vibration data of the vibration noise and to detect and process the vibration source of the air duct to be tested.

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