A defect safety assessment method and system for large-volume wrapped gas cylinders

Abstract

The present invention relates to a method and system for safety evaluation of defects of large-volume wrapped gas cylinders, the method comprising: obtaining working pressure and test pressure; controlling a booster pump to pressurize in steps to a working pressure stage and a test pressure stage according to the working pressure and the test pressure; the working pressure stage comprises a working pressure boosting stage and a working pressure maintaining stage; the test pressure stage comprises a test pressure boosting stage and a test pressure maintaining stage; respectively obtaining an acoustic emission signal of the working pressure stage and an acoustic emission signal of the test pressure stage; the characteristic parameters of the acoustic emission signal comprise an acoustic emission signal amplitude, a counting rate and an energy; and evaluating the safety of defects of large-volume wrapped gas cylinders according to the acoustic emission signal of the working pressure stage and the acoustic emission signal of the test pressure stage. The present invention can ensure the safe operation of gas cylinders and reduce operating costs.

Description

Technical Field

[0001] The present invention relates to the field of defect detection of wrapped gas cylinders, and in particular to a defect safety evaluation method and system for large-volume wrapped gas cylinders. Background Art

[0002] like Figure 1 As shown in the figure, the large-volume wrapped gas cylinder is composed of a seamless steel liner and a fiber wrapped layer, and is used for the transportation and storage of high-pressure hydrogen, natural gas, electronic gas, etc., with a volume greater than 2.0m 3 , is the medium storage unit in the long tube trailer. The application of large-volume wrapped gas cylinders is an important way to solve the high pressure and light weight of long tube trailers, and the transportation efficiency is improved by more than 20%.

[0003] During the use of large-volume wrapped gas cylinders, due to the long-tube trailer structure, working environment, worker operation and other reasons, it is easy to form defects such as wear, scratches, and impact on the wrapping layer. In particular, impact damage may cause internal fractures in the wrapping layer. In order to ensure the safe operation of large-volume wrapped gas cylinders, it is necessary to conduct a safety assessment on the safety of defective gas cylinders to determine whether they can continue to be used.

[0004] Large-volume wrapped gas cylinders have been used for a short time, lack of experimental research, and no scientific and reasonable evaluation methods and standards have been formed. At present, they are mainly evaluated with reference to the evaluation standards for medium and small-volume vehicle-mounted wrapped gas cylinders and respirator gas cylinders. During regular inspections, if the gas cylinders are found to have defects such as wear and scratches, the depth of the defects is measured. If the depth of the defects exceeds 1.25mm, the gas cylinders will be scrapped. If the gas cylinders are found to have impact damage, the gas cylinders will also be scrapped. Since the working environment of medium and small-volume wrapped gas cylinders is good and the value of a single gas cylinder is low, the current evaluation methods and standards can basically meet the requirements. However, for large-volume wrapped gas cylinders, the working environment is harsh and the value of a single gas cylinder is high. If the evaluation is carried out according to this evaluation method, a large number of defective gas cylinders will not pass the assessment and need to be scrapped, resulting in a waste of resources. A more scientific and reasonable evaluation method must be adopted to ensure the safe operation of gas cylinders and reduce operating costs.

[0005] like Figure 2 As shown in the figure, acoustic emission technology is a common non-destructive testing technology, which is often used to detect pressure vessels and structural parts. Acoustic emission refers to the phenomenon that solid materials break, deform, etc. under stress, release stored energy and generate elastic waves. Using the received acoustic emission signal to study materials and evaluate the integrity of the structure is called acoustic emission testing technology. Among them, the acoustic emission signal source of the winding layer is as follows Figure 3As shown in the figure, the main sources of acoustic emission in fiber-reinforced composite materials include: matrix cracking A; separation of fiber and matrix B; fiber pull-out C; fiber breakage D and fiber relaxation E. The matrix cracking, separation of fiber and matrix, fiber pull-out and fiber breakage of the winding layer of a large-volume wound gas cylinder under stress will trigger acoustic emission signals, which can be used to evaluate the safety of defects.

[0006] There are many existing studies and standards on the safety evaluation of wrapped gas cylinders based on acoustic emission technology. The current research objects are all medium and small volume gas cylinders. In addition, the current acoustic emission detection standards for wrapped gas cylinders mostly stipulate detection methods and procedures, and the regulations on defect safety evaluation are relatively vague, which cannot guide the safety evaluation of gas cylinder defects. The modal acoustic emission technology that has emerged in the past two years can realize the identification of fiber breakage signals, matrix cracking signals, and fiber and matrix separation signals, but this method is relatively complicated. In addition, due to the existence of the gas cylinder safety factor, when the gas cylinder safety factor is not enough to meet the requirements, fiber breakage and other phenomena do not occur, and this method also lacks practical significance.

[0007] Therefore, it is necessary to invent a method for evaluating defects of wrapped gas cylinders using acoustic emission technology to ensure safe operation of the gas cylinders and reduce operating costs. Summary of the invention

[0008] The purpose of the present invention is to provide a method and system for safety evaluation of defects in large-volume wrapped gas cylinders, so as to ensure safe operation of the gas cylinders and reduce operating costs.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] A defect safety assessment method for large-volume wrapped gas cylinders, comprising:

[0011] Obtain working pressure and test pressure;

[0012] According to the working pressure and the test pressure, the booster pump is controlled to step-by-step pressurize to the working pressure stage and the test pressure stage; the working pressure stage includes a working pressure boosting stage and a working pressure maintaining stage; the test pressure stage includes a test pressure boosting stage and a test pressure maintaining stage;

[0013] Acquiring the acoustic emission signal of the working pressure stage and the acoustic emission signal of the test pressure stage respectively; the characteristic parameters of the acoustic emission signal include the acoustic emission signal amplitude, counting rate and energy;

[0014] The safety of defects in large-volume wrapped gas cylinders is evaluated based on the acoustic emission signals in the working pressure stage and the acoustic emission signals in the test pressure stage.

[0015] Optionally, the safety assessment of defects of the large-volume wrapped gas cylinder according to the acoustic emission signal at the working pressure stage and the acoustic emission signal at the test pressure stage specifically includes:

[0016] The first set amplitude threshold, the first set count rate threshold and the first set energy threshold in the qualified condition are obtained through a burst test of a defective gas cylinder;

[0017] The explosion test of defective gas cylinders specifically includes:

[0018] Carry out burst tests on gas cylinders with different degrees of damage in turn to determine the critical damage state of the cylinder wrapping layer;

[0019] Collect the acoustic emission signals at the defects of the cylinder wrapping layer at the working pressure stage and the test pressure stage under the critical damage state;

[0020] Determine a first set amplitude threshold, a first set count rate threshold, and a first set energy threshold according to characteristic parameters of the acoustic emission signal at the defect in the working pressure stage and the test pressure stage under the critical damage state of the cylinder winding layer;

[0021] Determine whether the acoustic emission signal of the working pressure stage and the acoustic emission signal of the test pressure stage meet at least one of the qualified conditions to obtain a first judgment result; the qualified conditions include that the amplitude of the acoustic emission signal of the working pressure stage and the amplitude of the acoustic emission signal of the test pressure stage are both greater than a first set amplitude threshold, the count rate of the acoustic emission signal of the working pressure stage and the count rate of the acoustic emission signal of the test pressure stage are both greater than a first set count rate threshold, and the energy of the acoustic emission signal of the working pressure stage and the energy of the acoustic emission signal of the test pressure stage are both greater than a first set energy threshold;

[0022] If the first judgment result indicates yes, it is determined that the defect is unqualified and there is a safety problem;

[0023] If the first judgment result indicates no, it is determined that the defect is qualified and there is no safety problem.

[0024] A large-volume wrapped gas cylinder defect safety assessment system, applied to any of the large-volume wrapped gas cylinder defect safety assessment methods described above, the large-volume wrapped gas cylinder defect safety assessment system comprising: a booster pump, an acoustic emission sensor, a pressure sensor and an acoustic emission processing system;

[0025] The booster pump is connected to the large-volume wrapped gas cylinder; the booster pump is used to step-by-step pressurize the large-volume wrapped gas cylinder to a working pressure stage and a test pressure stage; the acoustic emission sensor is arranged at a defect of the large-volume wrapped gas cylinder; the acoustic emission sensor is used to detect the acoustic emission signal at the defect; the pressure sensor is arranged between the booster pump and the large-volume wrapped gas cylinder; the pressure sensor and the acoustic emission sensor are both connected to the acoustic emission processing system; the pressure sensor is used to detect the pressure; the acoustic emission processing system is used to process and display the acoustic emission signals at the defect in the working pressure stage and the test pressure stage so that subsequent processing can use the processing results to evaluate the safety of the gas cylinder.

[0026] Optionally, it further includes: an acoustic emission signal amplifier; the acoustic emission signal amplifier is connected to the acoustic emission sensor and the acoustic emission processing system respectively.

[0027] Optionally, it also includes: a display; the display is connected to the acoustic emission processing system; the display is used to display the working pressure, the test pressure and characteristic parameters of the acoustic emission signal; the characteristic parameters of the acoustic emission signal include amplitude, count rate and energy.

[0028] Optionally, the gain of the acoustic emission signal amplifier is 40dB.

[0029] Optionally, the frequency response range of the acoustic emission sensor is 100KHz to 400KHz.

[0030] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0031] The present invention provides a defect safety evaluation method and system for a large-volume wrapped gas cylinder, which obtains working pressure and test pressure; controls a booster pump to pressurize in steps to a working pressure stage and a test pressure stage according to the working pressure and the test pressure; the working pressure stage includes a working pressure boosting stage and a working pressure maintaining stage; the test pressure stage includes a test pressure boosting stage and a test pressure maintaining stage; respectively obtains an acoustic emission signal of the working pressure stage and an acoustic emission signal of the test pressure stage; characteristic parameters of the acoustic emission signal include acoustic emission signal amplitude, count rate and energy; evaluates the safety of defects of a large-volume wrapped gas cylinder according to the acoustic emission signal of the working pressure stage and the acoustic emission signal of the test pressure stage, realizes a scientific evaluation of the safety of defects, and can both ensure the safe operation of the gas cylinder and reduce the operating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0033] Figure 1 A schematic diagram of the structure of a large-volume wrapped gas cylinder provided by the present invention;

[0034] Figure 2 This is the principle diagram of acoustic emission detection;

[0035] Figure 3 This is the waveform diagram of the acoustic emission signal source of the winding layer;

[0036] Figure 4 A schematic diagram of the structure of a defect safety assessment system for large-volume wrapped gas cylinders provided by the present invention;

[0037] Figure 5 It is the system pressure stage diagram;

[0038] Figure 6 A flow chart for safety assessment of defects in large-volume wrapped gas cylinders provided by the present invention;

[0039] Figure 7 This is the amplitude diagram of the acoustic emission signal of gas cylinders with different degrees of damage;

[0040] Figure 8 This is the count rate diagram of acoustic emission signals of gas cylinders with different degrees of damage;

[0041] Fig. 9 This is the acoustic emission energy count rate diagram of gas cylinders with different degrees of damage;

[0042] Fig.10 This is a defect evaluation curve for large-volume wrapped gas cylinders.

[0043] Explanation of symbols:

[0044] 1-boosting pump; 2-pressure sensor; 3-acoustic emission signal amplifier; 4-acoustic emission sensor; 5-acoustic emission processing system; 6-display; 7-defect; 8-large volume wrapped gas cylinder. DETAILED DESCRIPTION

[0045] 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.

[0046] The purpose of the present invention is to provide a method and system for safety evaluation of defects in large-volume wrapped gas cylinders, so as to ensure safe operation of the gas cylinders and reduce operating costs.

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] like Figure 4 As shown, a defect safety assessment system for a large-volume wrapped gas cylinder provided by the present invention includes: a booster pump 1, an acoustic emission sensor, a pressure sensor 2 and an acoustic emission processing system 5.

[0049] The booster pump 1 is connected to the large volume wrapped gas cylinder 8; the booster pump 1 is used to step-by-step pressurize the large volume wrapped gas cylinder 8 to the working pressure stage and the test pressure stage; the acoustic emission sensor 4 is arranged at the defect 7 of the large volume wrapped gas cylinder 8; the acoustic emission sensor 4 is used to detect the acoustic emission signal at the defect 7; the acoustic emission sensor 4 is connected to the acoustic emission processing system 5; the pressure sensor 2 is arranged between the booster pump 1 and the large volume wrapped gas cylinder 8; the pressure sensor 2 is connected to the acoustic emission processing system 5; the pressure sensor 2 is used to detect the pressure. The acoustic emission processing system 5 is used to process and display the acoustic emission signals at the defect in the working pressure stage and the test pressure stage so that the subsequent processing can evaluate the safety of the gas cylinder using the processing results. In practical applications, the process of the acoustic emission processing system processing the acoustic emission signals at the defect in the working pressure stage and the test pressure stage can be processed manually or implemented using a computer program.

[0050] As an optional implementation, the defect safety assessment system for large-volume wrapped gas cylinders further includes an acoustic emission signal amplifier 3; the acoustic emission signal amplifier 3 is connected to the acoustic emission sensor 4 and the acoustic emission processing system 5 respectively.

[0051] As an optional embodiment, the large-volume wrapped gas cylinder defect safety assessment system also includes a display 6; the display 6 is connected to the acoustic emission processing system 5; the display 6 is used to display the working pressure, the test pressure, and the characteristic parameters of the acoustic emission signal; the characteristic parameters of the acoustic emission signal include amplitude, count rate and energy.

[0052] As an optional implementation, the gain of the acoustic emission signal amplifier is 40dB.

[0053] As an optional implementation, the response range of the acoustic emission sensor 4 is 100KHz to 400KHz.

[0054] like Figure 6 As shown, the present invention provides a large-volume wrapped gas cylinder defect safety assessment method, which is applied to the large-volume wrapped gas cylinder defect safety assessment system as described above, and the large-volume wrapped gas cylinder defect safety assessment method includes:

[0055] Obtain the working pressure and test pressure.

[0056] According to the working pressure and the test pressure, the booster pump is controlled to increase the pressure step by step to the working pressure stage and the test pressure stage; the working pressure stage includes a working pressure boosting stage and a working pressure maintaining stage; the test pressure stage includes a test pressure boosting stage and a test pressure maintaining stage.

[0057] The acoustic emission signal of the working pressure stage and the acoustic emission signal of the test pressure stage are respectively acquired; the characteristic parameters of the acoustic emission signal include the acoustic emission signal amplitude, counting rate and energy.

[0058] The safety of defects in large-volume wrapped gas cylinders is evaluated based on the acoustic emission signals in the working pressure stage and the acoustic emission signals in the test pressure stage.

[0059] In practical applications, the safety assessment of defects of large-volume wrapped gas cylinders based on the acoustic emission signals at the working pressure stage and the acoustic emission signals at the test pressure stage specifically includes:

[0060] The first set amplitude threshold, the first set count rate threshold and the first set energy threshold in the qualification condition are obtained through a burst test of a defective gas cylinder. The burst test of a defective gas cylinder specifically includes:

[0061] Explosion tests were carried out on gas cylinders with different degrees of damage in turn to determine the critical damage state of the cylinder wrapping layer.

[0062] Acoustic emission signals are collected at defects in the working pressure stage and the test pressure stage under the critical damage state of the cylinder winding layer.

[0063] The first set amplitude threshold, the first set count rate threshold and the first set energy threshold are determined according to the characteristic parameters of the acoustic emission signal at the defect in the working pressure stage and the test pressure stage under the critical damage state of the cylinder winding layer.

[0064] It is judged whether the acoustic emission signal of the working pressure stage and the acoustic emission signal of the test pressure stage meet at least one of the qualified conditions to obtain a first judgment result; the qualified conditions include that the amplitude of the acoustic emission signal of the working pressure stage and the amplitude of the acoustic emission signal of the test pressure stage are both greater than a first set amplitude threshold, the count rate of the acoustic emission signal of the working pressure stage and the count rate of the acoustic emission signal of the test pressure stage are both greater than a first set count rate threshold, and the energy of the acoustic emission signal of the working pressure stage and the energy of the acoustic emission signal of the test pressure stage are both greater than a first set energy threshold.

[0065] If the first judgment result indicates yes, it is determined that the defect is unqualified and there is a safety problem.

[0066] If the first judgment result indicates no, it is determined that the defect is qualified and there is no safety problem.

[0067] By conducting burst tests on large-volume wrapped gas cylinders with different degrees of damage, such as slight damage, moderate damage, etc., we can determine the Fig.10 The gas cylinder bursting pressure curve and the critical bursting pressure of the gas cylinder are shown, and the acoustic emission signals at the damaged parts are collected during the blasting process to obtain the acoustic emission signal activity curves of large-volume wrapped gas cylinders with different degrees of damage, as well as the characteristic parameters of the acoustic emission signals under the critical damage state, and the characteristic parameters in this state are used as the evaluation threshold.

[0068] The present invention provides a specific workflow for safety evaluation of defects of large-volume wrapped gas cylinders in practical applications.

[0069] (1) Figure 5 As shown, the large-volume wrapped gas cylinder 8 is pressurized step by step by the booster pump 1 to the working pressure of the gas cylinder, and the pressure is maintained at this pressure for a period of time, and then the pressure is increased to the test pressure, and the pressure is maintained at this pressure for a period of time.

[0070] (2) During the two-stage pressurization and pressure-maintaining operation of the gas cylinder, a load is applied to the defect of the large container wrapped around the gas cylinder, and the defect releases an acoustic emission signal, which is acquired by the acoustic emission sensor 4 and amplified by the acoustic emission amplifier. The signal is transmitted to the acoustic emission processing system 5.

[0071] (3) During the two-stage pressurization and pressure-maintaining process, the pressure signal is also transmitted to the acoustic emission processing system 5 through the pressure sensor 2.

[0072] (4) The acoustic emission signal and its characteristic parameters are displayed by the display system, and the signal is analyzed and studied. The safety of the defect of large container wrapped around the gas cylinder is judged by signal analysis. The method for judging the safety of the defect is as follows:

[0073] (4-1) Evaluate the acoustic emission signal amplitude of the large volume wrapped gas cylinder 8 during the pressurization stage

[0074] like Figure 7 As shown, Figure 7 (a) is the amplitude diagram of the acoustic emission signal during the detection of an undamaged gas cylinder. Figure 7 (b) is the amplitude diagram of the acoustic emission signal of the slightly damaged gas cylinder during the pressurization stage. Figure 7 (c) is the amplitude diagram of the acoustic emission signal during the detection of moderately damaged gas cylinders. Figure 7 (d) is the amplitude diagram of the acoustic emission signal during the detection of the critical damage cylinder. As the degree of damage to the cylinder varies, the amplitude of the acoustic emission signal increases in the 0 to working pressure and working pressure to test pressure boost stages. For the critical damage cylinder, there are a large number of high-amplitude signals above 80dB, while the signal amplitude of the undamaged cylinder is lower than 80dB, and there are only a few signals above 80dB for the slightly damaged and moderately damaged cylinders. Among them, the first set amplitude threshold is 80dB.

[0075] (4-2) Evaluate by the acoustic emission signal count rate of large volume wrapped gas cylinder 8 during the pressurization stage

[0076] like Figure 8 As shown, Figure 8 (a) is the acoustic emission signal count rate diagram during the detection of undamaged gas cylinders. Figure 8 (b) is the acoustic emission signal count rate diagram during the detection of slightly damaged gas cylinders. Figure 8 (c) is the acoustic emission signal count rate diagram during the detection of moderately damaged gas cylinders. Figure 8 (d) is the acoustic emission signal count rate diagram during the detection of critical damage state cylinders. With the different damage degrees of the cylinders, the acoustic emission signal count rate increases successively in the pressure-up stage from 0 to working pressure and from working pressure to test pressure, and the activity of the damaged area is significantly enhanced. For the critical damage state cylinder, the acoustic emission signal count rate in the pressure-up stage can reach 2.0×10 3 The signal counting rate of the undamaged gas cylinder is only 20 / s, while the acoustic emission signal counting rate of the slightly damaged gas cylinder is 100 / s, and the acoustic emission signal counting rate of the moderately damaged gas cylinder increases to 300 / s. The activity of the critically damaged gas cylinder is about 100 times higher than that of the undamaged gas cylinder.

[0077] (4-3) The acoustic emission signal energy of the large volume wrapped gas cylinder 8 during the pressurization stage is used to evaluate the Fig. 9 As shown, Fig. 9 (a) is the energy diagram of the acoustic emission signal during the detection of an undamaged gas cylinder. Fig. 9 (b) is the energy detection diagram of acoustic emission signal during the detection of slightly damaged gas cylinders. Fig. 9 (c) is the energy detection diagram of acoustic emission signal during the detection of moderately damaged gas cylinders. Fig. 9 (d) is the energy diagram of the acoustic emission signal during the detection of severely damaged gas cylinders. As the degree of damage to the gas cylinders varies, the energy of the acoustic emission signal increases in the pressure-up phase from 0 to working pressure and from working pressure to test pressure. The signal strength increases in turn. For a gas cylinder in a critically damaged state, the energy of the acoustic emission signal in the pressure-up phase can reach 2.0×10 6 aJ, while the signal energy of the undamaged cylinder is less than 1.0×10 5 aJ, and the signal energy of slightly damaged and moderately damaged cylinders is basically 1.0×10 5 aJ, The signal intensity of the critically damaged cylinder is about 10 times higher than that of the undamaged cylinder.

[0078] The method provided by the present invention can be seen:

[0079] (1) In the pressure rise and pressure maintenance stages from 0 to working pressure, and from working pressure to test pressure, severely damaged gas cylinders generate a large number of high-amplitude signals above 80 dB, with a count rate of 2.0×10 3 / s, the activity increased 100 times, and the signal intensity reached 2.0×10 6 electron volt, the intensity increases 10 times.

[0080] (2) The amplitude, count rate, energy and other characteristics of the acoustic emission signal of the large-volume wrapped gas cylinder 8 change significantly with the damage of the gas cylinder during the pressure increase and pressure maintenance stages from 0 to working pressure, and from working pressure to test pressure. The degree of damage to the gas cylinder is evaluated by combining the amplitude, count rate and intensity of the acoustic emission signal in the damaged area.

[0081] The system and method provided by the present invention use acoustic emission technology to install an acoustic emission sensor 4 at the defect 7 of a large-volume wrapped gas cylinder 8 to complete the safety detection of the defect 7, which can ensure the safe operation of the gas cylinder and reduce the operating cost.

[0082] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0083] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, 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 the present invention.

Claims

1. A defect safety assessment method for large-volume wrapped gas cylinders, characterized in that: include: Obtaining a working pressure and a test pressure; the test pressure is greater than the working pressure; According to the working pressure and the test pressure, the booster pump is controlled to step-by-step pressurize to the working pressure stage and the test pressure stage; the working pressure stage includes a working pressure boosting stage and a working pressure maintaining stage; the test pressure stage includes a test pressure boosting stage and a test pressure maintaining stage; Acquiring the acoustic emission signal of the working pressure stage and the acoustic emission signal of the test pressure stage respectively; the characteristic parameters of the acoustic emission signal include the acoustic emission signal amplitude, count rate and energy; Evaluate the safety of defects of large-volume wrapped gas cylinders based on the acoustic emission signals at the working pressure stage and the acoustic emission signals at the test pressure stage; The safety assessment of defects of the large-volume wrapped gas cylinder according to the acoustic emission signal at the working pressure stage and the acoustic emission signal at the test pressure stage specifically includes: Perform burst tests on gas cylinders with different degrees of damage in sequence to determine the critical damage state of the gas cylinder winding layer; collect acoustic emission signals at defects in the working pressure stage and the test pressure stage under the critical damage state of the gas cylinder winding layer; determine a first set amplitude threshold, a first set count rate threshold, and a first set energy threshold according to characteristic parameters of the acoustic emission signals at defects in the working pressure stage and the test pressure stage under the critical damage state of the gas cylinder winding layer; Determine whether the acoustic emission signal of the working pressure stage and the acoustic emission signal of the test pressure stage meet at least one qualified condition to obtain a first judgment result; the qualified condition includes that the amplitude of the acoustic emission signal of the working pressure stage and the amplitude of the acoustic emission signal of the test pressure stage are both greater than a first set amplitude threshold, the count rate of the acoustic emission signal of the working pressure stage and the count rate of the acoustic emission signal of the test pressure stage are both greater than a first set count rate threshold, and the energy of the acoustic emission signal of the working pressure stage and the energy of the acoustic emission signal of the test pressure stage are both greater than a first set energy threshold; If the first judgment result indicates yes, it is determined that the defect is unqualified and there is a safety problem; If the first judgment result indicates no, it is determined that the defect is qualified and there is no safety problem.

2. A defect safety assessment system for large-volume wrapped gas cylinders, characterized in that: Applied to the defect safety assessment method for large-volume wrapped gas cylinders as claimed in claim 1, the defect safety assessment system for large-volume wrapped gas cylinders comprises: a booster pump, an acoustic emission sensor, a pressure sensor and an acoustic emission processing system; The booster pump is connected to the large-volume wrapped gas cylinder; the booster pump is used to step-by-step pressurize the large-volume wrapped gas cylinder to the working pressure stage and the test pressure stage, and the test pressure is greater than the working pressure; the acoustic emission sensor is arranged at the defect of the large-volume wrapped gas cylinder; the acoustic emission sensor is used to detect the acoustic emission signal at the defect; the pressure sensor is arranged between the booster pump and the large-volume wrapped gas cylinder; the pressure sensor and the acoustic emission sensor are both connected to the acoustic emission processing system; the pressure sensor is used to detect the pressure; the acoustic emission processing system is used to process and display the acoustic emission signals at the defect in the working pressure stage and the test pressure stage so that subsequent processing can use the processing results to evaluate the safety of the gas cylinder; The use of the processing results to evaluate the safety of the gas cylinder specifically includes: Perform burst tests on gas cylinders with different degrees of damage in sequence to determine the critical damage state of the gas cylinder winding layer; collect acoustic emission signals at defects in the working pressure stage and the test pressure stage under the critical damage state of the gas cylinder winding layer; determine a first set amplitude threshold, a first set count rate threshold, and a first set energy threshold according to characteristic parameters of the acoustic emission signals at defects in the working pressure stage and the test pressure stage under the critical damage state of the gas cylinder winding layer; Determine whether the acoustic emission signal of the working pressure stage and the acoustic emission signal of the test pressure stage meet at least one qualified condition to obtain a first judgment result; the qualified condition includes that the amplitude of the acoustic emission signal of the working pressure stage and the amplitude of the acoustic emission signal of the test pressure stage are both greater than a first set amplitude threshold, the count rate of the acoustic emission signal of the working pressure stage and the count rate of the acoustic emission signal of the test pressure stage are both greater than a first set count rate threshold, and the energy of the acoustic emission signal of the working pressure stage and the energy of the acoustic emission signal of the test pressure stage are both greater than a first set energy threshold; If the first judgment result indicates yes, it is determined that the defect is unqualified and there is a safety problem; If the first judgment result indicates no, it is determined that the defect is qualified and there is no safety problem.

3. The defect safety assessment system for large-volume wrapped gas cylinders according to claim 2 is characterized in that: Also includes: Acoustic emission signal amplifier; the acoustic emission signal amplifier is connected to the acoustic emission sensor and the acoustic emission processing system respectively.

4. The defect safety assessment system for large-volume wrapped gas cylinders according to claim 2 is characterized in that: Also includes: monitor; The display is connected to the acoustic emission processing system; the display is used to display the working pressure, the test pressure and characteristic parameters of the acoustic emission signal; The characteristic parameters of the acoustic emission signal include amplitude, count rate and energy.

5. The defect safety assessment system for large-volume wrapped gas cylinders according to claim 3 is characterized in that: The gain of the acoustic emission signal amplifier is 40dB.

6. The defect safety assessment system for large-volume wrapped gas cylinders according to claim 2 is characterized in that: The frequency response range of the acoustic emission sensor is 100KHz to 400KHz.

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