Airtightness detection method and device

Abstract

The invention discloses an air tightness detection method, which comprises the following steps: placing a test product in a sealing chamber of an air tightness detection tool, and indirectly detecting the sealing performance of the test product according to the gas pressure in the air tightness detection tool; specifically, if a large leakage point exists on a test product, the internal space of the test product is communicated with a sealing chamber of the airtightness detection tool, and then the difference value between the first detection pressure after the test gas is filled according to a section of gas filling condition and the first detection pressure after the test gas is filled under the same condition of a qualified product is large. Therefore, rapid and accurate judgment of a large leakage point can be realized through the first detection pressure; when leakage judgment is carried out, judgment is carried out according to the gas leakage amount of the test product filled with the test gas under the same two-section inflation condition, and the airtightness of the test product can be detected more accurately. The invention further discloses an air tightness detection device.

Description

Technical Field

[0001] The present invention belongs to the technical field of airtight detection, and specifically relates to an airtight detection method and device. Background Art

[0002] In the modern industrial system, for products with the nature of airtight containers, airtight detection is an important part of product quality control. It is widely used in fields such as automobile manufacturing, electronic equipment, petrochemical industry, aerospace industry, and medical devices. By effective detection, it ensures that the airtight performance of products meets the usage requirements to avoid economic losses and safety hazards caused by air leakage and liquid leakage. According to the detection requirements of different products, conventional detection methods include the bubble method, the smear method, the pressure change method, the flow method, the chemical gas tracer method, the ultrasonic method, etc.; among them, the bubble method and the smear method have low detection accuracy, long detection cycles, and cannot achieve automation; while the chemical gas tracer method and the ultrasonic method have higher accuracy but relatively high usage costs; so currently, the pressure change method and the flow method are generally commonly used for airtight detection methods.

[0003] The outer shell of disposable blood perfusion devices for three types of medical devices, as a container for loading adsorption particles and filling liquid, plays a role in isolating bacteria and blocking dust, avoiding internal adsorption particles and filling liquid from being contaminated. During the product life cycle, good sealing performance should be ensured, and the outer shell should be intact without leakage, so as to maintain the safety and reliability during the treatment and use of patients. Summary of the Invention

[0004] Existing conventional airtight detection methods for medical devices or biomedical-related injection molded products generally adopt the pressure change method, which can achieve high-precision airtight detection for simple cavity airtight containers. However, the applicant has found that for products with porous structure media as internal fillers, such as blood adsorption products for blood purification treatment, hollow fiber membrane purification products, or membrane filtration separation products used in fields such as water treatment, biopharmaceuticals, and food fermentation, when test gas is filled into the product, the detection results of the pressure change method are inaccurate; through the research of the applicant, it is found that due to the characteristics of large specific surface area and strong adsorption performance of the porous structure filler, the filler will absorb a part of the test gas, resulting in an extended overall product detection cycle and a significant decrease in detection accuracy.

[0005] In view of this, in order to solve the deficiencies of the existing technology, the purpose of the present invention is to provide an airtight detection method and device.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: An airtight detection method includes the following steps: Step 1: Loading the product: Load the test product into the sealed chamber of the airtight detection tooling and make the airtight detection tooling airtight; Step 2: Primary inflation: Fill the airtight detection tooling with test gas at the first set flow rate and for the first set time to a first set pressure, and detect the first detection pressure inside the airtight detection tooling. Step 3: Large leak point judgment: Determine whether there is a large leak point in the test product based on the detected first detection pressure. If so, it indicates that there is a large leak point in the test product, the airtight detection of the test product is unqualified, the detection ends, and step 8 is executed. If not, it indicates that there is no large leak point in the test product, and step 4 is executed. Step 4: Secondary inflation: After depressurizing and exhausting the airtight detection tooling, fill the airtight detection tooling with test gas at a second set pressure until the gas inside the airtight detection tooling stabilizes and then stop inflation. Step 5: Pressure holding and balancing: Hold the pressure of the airtight detection tooling to balance it so that the pressure inside the airtight detection tooling reaches a balanced and stable state. Step 6: Leakage measurement: Measure the pressure change of the airtight detection tooling and use an airtight instrument to read the gas leakage amount. Step 7: Leakage judgment: Determine whether there is leakage in the test product based on the gas leakage amount. If so, it is determined that the airtight detection of the test product is unqualified. If not, it is determined that the airtight detection of the test product is qualified. Step 8: Unload the product: After depressurizing and exhausting the airtight detection tooling, open the airtight detection tooling and take out the test product.

[0007] Furthermore, in step 2, the inflation time into the airtight detection tooling is controlled within 2 - 8 seconds, and the first set pressure is controlled within 200 - 350 KPa.

[0008] Furthermore, the method for determining whether there is a large leak point in the test product based on the first detection pressure value is as follows: Determine whether the maximum value of the first detection pressure is less than the preset first detection pressure threshold. If so, it indicates that there is a large leak point in the test product. If not, it indicates that there is no large leak point in the test product. The first detection pressure threshold is set based on the first detection pressure measured for qualified products under the same primary inflation conditions; or, Take the ratio of the first detection pressure to the set test pressure as the pressure conversion ratio, and determine whether the pressure conversion ratio is less than the preset first pressure conversion ratio threshold. If so, it indicates that there is a large leak point in the test product. If not, it indicates that there is no large leak point in the test product. The first pressure conversion ratio threshold is set based on the ratio between the detected pressure and the set test pressure measured for qualified products under the same primary inflation conditions.

[0009] Furthermore, in step 4, the inflation time into the airtight detection tooling for the test gas is controlled within 20 - 30 seconds, and the second set pressure is controlled within 250 - 300 KPa.

[0010] Further, in the fifth step, the pressure holding and balancing time is controlled within 60 - 90 seconds; in the sixth step, the time for gas leakage is controlled within 15 - 20 seconds.

[0011] Further, in the seventh step, the method for judging whether the test product has leakage according to the gas leakage amount is as follows: judge whether the gas leakage amount is greater than a preset leakage determination value: if so, it is determined that the airtightness detection of the test product is unqualified; if not, it is determined that the airtightness detection of the test product is qualified; the leakage determination value is set according to the gas leakage amount measured under the same two - stage inflation conditions for qualified products.

[0012] The present invention also provides an airtightness detection device applicable to the above - mentioned airtightness detection method, including an airtightness detection tooling and an air circuit system. The air circuit system is connected to the airtightness detection tooling and is used to fill the airtightness detection tooling with test gas. The airtightness detection tooling has a sealed chamber for accommodating the test product, and the shape of the sealed chamber is the same as that of the test product, so that an inflation sandwich layer is formed between the sealed chamber and the test product when the test product is placed.

[0013] Further, the air circuit system includes a compressed air system, a pressure regulating valve group, an airtightness detector and a filter group connected in series in sequence. The air outlet of the filter group is connected to the air inlet of the airtightness detection tooling.

[0014] Further, the pressure regulating valve group includes a total test gas pressure regulating valve and an independent station pressure regulating valve connected in series. The air inlet of the total test gas pressure regulating valve is connected to the compressed air system, and the air outlet of the independent station pressure regulating valve is connected to the airtightness detector.

[0015] Further, the filter group includes a sterile filter and an impurity filter connected in series. The air inlet of the sterile filter is connected to the airtightness detector, and the air outlet of the impurity filter is connected to the air inlet of the airtightness detection tooling.

[0016] Further, the airtightness detection tooling includes a upper tooling and a lower tooling that cooperate with each other. A mold locking device is provided between the upper tooling and the lower tooling. The mold locking device is used to tightly press - fit the upper tooling and the lower tooling and form a sealed chamber for placing the test product between the upper tooling and the lower tooling.

[0017] Further, the test product is placed in the sealed chamber in the horizontal direction of the axis; the connection position of the air circuit system and the airtightness detection tooling is located at the upper part of the airtightness detection tooling.

[0018] The beneficial effects of the present invention are as follows: The airtight detection method of the present invention indirectly detects the sealing performance of a test product by placing the test product in the sealed chamber of an airtight detection tooling and according to the gas pressure in the airtight detection tooling. Specifically, if there is a large leak point on the test product, it will cause the internal space of the test product to communicate with the sealed chamber of the airtight detection tooling, resulting in an increase in the space in the airtight detection tooling that can store gas. Consequently, the difference between the first detection pressure after filling the test gas under a certain inflation condition and the first detection pressure after filling the test gas for a qualified product under the same condition will be relatively large. In this way, the large leak point can be quickly and accurately judged through the first detection pressure. When judging a minor leak, it is judged according to the gas leakage amount of the test product after filling the test gas under the same second-stage inflation condition, enabling a more precise detection of the airtightness of the test product. This detection method must be combined with two-stage inflation testing to obtain reliable test results. If only the one-stage inflation testing method is used, unqualified products with minor leaks cannot be identified; if only the pressure-holding testing method of two-stage inflation is adopted, unqualified products with large leak points cannot be identified. In summary, the airtight detection method of the present invention indirectly detects the sealing performance of a test product by placing the test product in the sealed chamber of an airtight detection tooling and according to the gas pressure in the airtight detection tooling, which can avoid the interference of porous materials that can absorb gas in the test product on gas pressure detection, thereby effectively improving the sealing detection accuracy of the test product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the objectives, technical solutions, and beneficial effects of the present invention clearer, the following drawings are provided for illustration: Figure 1 It is a flowchart of the airtight detection method of the present invention; Figure 2 It is a schematic diagram of the airtight detection device of the present invention; Figure 3 It is a schematic connection diagram of the gas circuit system; Figure 4 It is a schematic structural diagram of a product airtight detection tooling; Figure 5 It is a schematic structural diagram of another product airtight detection tooling.

[0020] Description of the reference numerals: 10 - airtight detection tooling; 11 - upper tooling; 12 - lower tooling; 12 - sealed inner cavity; 20 - gas circuit system; 21 - compressed air system; 22 - pressure regulating valve group; 221 - total test gas pressure regulating valve; 222 - independent station pressure regulating valve; 23 - airtightness detector; 24 - filter group; 241 - sterile filter; 242 - impurity filter; 30 - test workpiece; 40 - cylinder. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited do not limit the present invention.

[0022] As Figure 1 shown, the airtight detection method of this embodiment includes the following steps.

[0023] Step 1: Loading the product: Load the test product into the sealed chamber of the airtight detection tooling and seal the airtight detection tooling.

[0024] Step 2: First-stage inflation: Inflate the airtight detection tooling with a test gas at a first set flow rate and a first set time to a first set pressure, and detect the first detection pressure inside the airtight detection tooling. Specifically, the inflation time into the airtight detection tooling is controlled within 2 - 8 seconds, and the first set pressure is controlled within 200 - 350 KPa. The first set flow rate can be set according to the remaining volume of the sealed chamber of the airtight detection tooling after removing the test product. Specifically, if the remaining volume is large, the first set flow rate should be increased; if the remaining volume is small, the first set flow rate can be appropriately decreased; the inflation time can also be adjusted adaptively; thus, to ensure that there is sufficient air pressure in the sealed chamber of the airtight detection tooling after the first-stage inflation, so as to improve the accuracy of large leak point detection and judgment.

[0025] Step 3: Large leak point judgment: Judge whether the test product has a large leak point according to the detected first detection pressure: If so, it indicates that the test product has a large leak point, the airtight detection of the test product is unqualified, the detection ends, and step 8 is executed; if not, it indicates that the test product has no large leak point, and step 4 is executed.

[0026] In some embodiments, when judging the large leak point, it can be directly judged according to the first detection pressure. That is, the method for judging whether the test product has a large leak point according to the first detection pressure value is: Judge whether the maximum value of the first detection pressure is less than the preset first detection pressure threshold: If so, it indicates that the test product has a large leak point; if not, it indicates that the test product has no large leak point; the first detection pressure threshold is set according to the first detection pressure measured under the same first-stage inflation conditions for qualified products.

[0027] Due to certain errors in products of different batches, etc., the fluctuation range of the first detection pressure is relatively large. If the first detection pressure is directly used to judge large leak points, there may be a problem of insufficient judgment accuracy. Therefore, in a preferred embodiment, when judging large leak points, the first detection pressure can be converted by a geometric ratio to narrow the fluctuation value range. That is, the method for judging whether there is a large leak point in the test product according to the first detection pressure value is: taking the ratio of the first detection pressure to the set test pressure as the pressure conversion ratio, and judging whether the pressure conversion ratio is less than the preset first pressure conversion ratio threshold: if so, it indicates that there is a large leak point in the test product; if not, it indicates that there is no large leak point in the test product. Specifically, the set test pressure is the preset fixed pressure value for the geometric ratio conversion of the first detection pressure, and the first pressure conversion ratio threshold is set according to the ratio between the detection pressure measured under the same inflation conditions for qualified products and the set test pressure.

[0028] Step Four: Secondary Inflation: After relieving the pressure and exhausting the air from the airtight detection tooling, fill the airtight detection tooling with test gas at the second set pressure until the gas in the airtight detection tooling is stable and then stop inflation. Specifically, the time for filling the test gas into the airtight detection tooling is controlled within 20 - 30 seconds, and the second set pressure is controlled within 100 - 350 KPa.

[0029] Step Five: Pressure Holding and Balancing: Perform pressure holding and balancing on the airtight detection tooling to make the pressure inside the airtight detection tooling reach a balanced and stable state; specifically, the pressure holding and balancing time is controlled within 60 - 90 seconds.

[0030] Step Six: Leakage Measurement: Measure the pressure change of the airtight detection tooling and read the gas leakage amount using an airtight instrument; specifically, the time for measuring the gas leakage amount is controlled within 15 - 20 seconds.

[0031] The gas leakage amount mentioned here is actually the pressure change value read by the airtight instrument.

[0032] Step Seven: Leakage Judgment: Judge whether there is leakage in the test product according to the gas leakage amount: if so, it is determined that the airtight detection of the test product is unqualified; if not, it is determined that the airtight detection of the test product is qualified.

[0033] In this embodiment, the method for judging whether there is leakage in the test product according to the gas leakage amount is: judging whether the gas leakage amount is greater than the preset leakage judgment value: if so, it is determined that the airtight detection of the test product is unqualified; if not, it is determined that the airtight detection of the test product is qualified; the leakage judgment value is set according to the gas leakage amount measured for qualified products under the same secondary inflation conditions. Qualified products are products selected through a more stringent test under higher pressure test conditions according to the test methods specified in the industry standard.

[0034] Step Eight: Unload the product: After releasing the pressure and exhausting the air from the airtight detection tooling, open the airtight detection tooling and take out the test product.

[0035] The method of the present invention is used for test comparison with the conventional pressure change method. The conventional pressure change method - the internal pressure method is a common method for detecting the pressure change or leakage by filling pressurized gas or liquid into the container or system to be tested; for example, in YY T 0464-2019 "Disposable Blood Perfusion Device", the detection method for the product sealing performance is to fill the perfusion device with pressurized air (about 50 kPa) to empty it, seal one end and pressurize the other end to 100 kPa, immerse it in water at 23°C ± 2°C, and observe for 10 minutes to confirm whether there is leakage. However, considering that the operation of the industry standard method is complex and time-consuming and cannot meet the requirements of the normal production cycle, the initial detection method is to fill the sealed workpiece with high-pressure gas (2-3 times the industry standard pressure, and obvious pressure change is formed in a short time through a higher pressure to determine the unqualified workpiece) to the target pressure, close the gas source after the pressure is stable, and monitor the pressure drop value within a period of time. If the final pressure drop exceeds the allowable threshold of the qualified workpiece, it is determined as unqualified. Under the condition of keeping the parameters such as the test pressure and the pressure holding time the same, the samples are divided into two groups, and the detection results of the internal pressure method and the airtight detection method of the present invention are compared, as shown in Table 1. It can be seen that for some slightly leaking products, the internal pressure method cannot detect them, while the method of the present invention can identify them. The leakage detection sensitivity of the method of the present invention is higher than that of the internal pressure method, and the detection reliability is better, which can effectively eliminate the influence of the internal filler of the container on the test medium.

[0036] Table 1 Comparison of airtight detection results between the method of the present invention and the internal pressure method Next, the specific implementation manner of the airtight detection device applicable to the above airtight detection method of this embodiment will be described in detail.

[0037] As Figure 2 and Figure 3 shown, the airtight detection device of this embodiment includes an airtight detection tooling 10 and a gas path system 20. The gas path system 20 is connected to the airtight detection tooling 10 and is used to fill the airtight detection tooling 10 with test gas. The airtight detection tooling 10 has a sealed chamber for accommodating the test product 30. The sealed chamber is of conformable design and has the same shape as the outer shape of the test product 30, so that an inflation sandwich layer is formed between the sealed chamber and the test product 30 when the test product 30 is placed in it. Since the external inflation method is used for testing, in order to save the inflation time and improve the test accuracy, the thickness of the inflation sandwich layer should be relatively small, which can be 0-5 cm, more preferably 0.1-1 cm.

[0038] Specifically, the gas path system 20 of this embodiment includes a compressed air system 21, a pressure regulating valve group 22, an airtightness detector 23, and a filter group 24 connected in series in sequence. The air outlet of the filter group 24 is connected to the air inlet of the airtightness detection tooling 10. The pressure regulating valve group 22 may include one or more than two pressure regulating valves. The filter group 24 may include one or more than two filters.

[0039] In this embodiment, the pressure regulating valve group 22 includes a total test gas pressure regulating valve 221 and an independent station pressure regulating valve 222 connected in series. The air inlet of the total test gas pressure regulating valve 221 is connected to the compressed air system 21, and the air outlet of the independent station pressure regulating valve 222 is connected to the airtightness detector 23. The total test gas pressure regulating valve 221 controls the gas pressure entering the main pipeline of the equipment test to avoid excessive pressure leading to leakage and pipe explosion (the pressure resistance of the test pipeline and the gas pressure of the compressed air system jointly determine). The series-connected independent pressure regulating valve 222 is to ensure that the gas pressures of each branch pipeline of the main pipeline are basically the same, ensuring the same test conditions for each independent station.

[0040] In this embodiment, the filter group 24 includes a sterile filter 241 and an impurity filter 242 connected in series. The air inlet of the sterile filter 241 is connected to the airtightness detector 23, and the air outlet of the impurity filter 242 is connected to the air inlet of the airtightness detection tooling 10. The sterile filter 241 is provided to ensure that the test gas entering the inner cavity of the tooling and contacting the product is clean and pollution-free, avoiding excessive microorganisms on the product surface; the series-connected impurity filter 242 is to avoid the possible outflow of the internal filler of the product when the product leaks and deflates and is sucked back into the airtight instrument, causing a malfunction.

[0041] The airtightness detection tooling 10 of this embodiment includes a cooperating upper tooling 11 and a lower tooling 12. A mold locking device (not shown in the figure) is provided between the upper tooling 11 and the lower tooling 12. The mold locking device is used to tightly press and fit the upper tooling 11 and the lower tooling 12, and form a sealed chamber 13 for placing the test product 30 between the upper tooling 11 and the lower tooling 12.

[0042] In this embodiment, as Figure 4 , the test product 30 is a blood adsorption and purification product, and its interior may contain liquid. If the air inlet of the airtightness detection tooling 10 is set at the lower part of the tooling, when the airtightness detection tooling 10 exhausts and deflates internally, the liquid inside the leaking test product 30 will be sucked back and flow into the lower part of the tooling and enter the airtightness detector 30 through the air inlet and the gas path pipeline, resulting in sensor failure. Therefore, the air inlet of the airtightness detection tooling 10 is set at the upper half of the tooling. In this embodiment, the connection position where the gas path system 20 is connected to the airtightness detection tooling 10 is located at the upper part of the airtightness detection tooling 10. Specifically, the air inlet of the airtightness detection tooling 10 is set on the upper tooling 11.

[0043] In this embodiment, the test product 30 can be placed in the sealed chamber 13 in the vertically axial direction or in the horizontally axial direction. However, since the test product 30 is shaped like a dumbbell, and the upper tooling 11 moves relative to the lower tooling 12 in the vertical direction under the driving action of the cylinder 40 to open or close the airtight detection tooling 10. Therefore, if the test product 30 is placed in the vertically axial direction, the sealed inner cavity 13 must be designed according to the maximum outer diameter of the test product 30. Considering the need for placing the part, the sealed inner cavity 13 must be a cylinder with the maximum outer diameter of the test product 30 as the diameter, resulting in a relatively large volume of the sealed inner cavity 13. At the same time, it will also lead to a relatively large size of the airtight detection tooling 10, and a relatively large volume of the sealed inner cavity 13 excluding the test product 30, resulting in a lower detection accuracy. Therefore, in this embodiment, the test product 30 is placed in the inner cavity in the horizontally axial direction. In this way, the sealed inner cavity 13 can be designed to be shaped like the test product 30. At this time, the volume of the sealed inner cavity 13 is only one-third of that when placed in the vertically axial direction, greatly reducing the detection volume, effectively improving the detection accuracy, and at the same time, the operation convenience of placing the test product 30 in the horizontally axial direction is better than that of placing the test product 30 in the vertically axial direction.

[0044] In another embodiment, as Figure 5 , the test product 30 is a hollow fiber membrane filter product, such as a hemodialyzer, a plasma separator, a dialysate filter, a water treatment filter, an air purification filter, or a biomass solution membrane separator. For such hollow fiber membrane products, using the external air inflation and pressure maintenance of the present invention can avoid the adverse effects of air inflation on the internal fibers compared with the traditional method of inflating and bubbling inside the fiber membrane, such as possible changes in fiber distribution resulting in changes in hydrodynamic characteristics. When the test product 30 has a high requirement for a sterile environment, the filter group 24 includes a sterile filter 241 and an impurity filter 242 connected in series; when the test product 30 has no sterile requirement, only the impurity filter 242 needs to be provided.

[0045] The above-described embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Claims

1. An airtightness detection method, characterized in that: The steps include: Step 1: Loading the product: Load the test product into the sealed chamber of the airtight testing tooling and make the airtight testing tooling airtight; Step 2: One-stage inflation: filling the airtightness testing tool with a test gas of a first set pressure according to a first set flow rate and a first set time, and detecting a first test pressure in the airtightness testing tool; Step 3: Determine whether the test product has a large leak: Determine whether the test product has a large leak based on the first test pressure obtained during the test: If yes, it indicates that the test product has a large leak, the airtightness test of the test product fails, the test ends, and the step eight is executed; if no, it indicates that the test product has no large leak, and the step four is executed; Step 4: Second stage inflation: After the airtightness testing tool is depressurized and exhausted, the test gas of the second set pressure is filled into the airtightness testing tool until the gas in the airtightness testing tool is stable and then the inflation is stopped; Step 5: Pressure balance: Perform pressure balance on the airtightness testing tooling to make the pressure inside the airtightness testing tooling reach a balanced and stable state; Step 6: Leakage measurement: Measure the pressure change of the airtight detection tooling and read the gas leakage using the airtight instrument; Step 7: Leakage judgment: judge whether the test product has leakage according to the gas leakage amount: if yes, the airtightness test of the test product is judged to be unqualified; if no, the airtightness test of the test product is judged to be qualified; Step 8: Unload the product: After venting the airtightness test tooling, open the airtightness test tooling and take out the test product.

2. The airtightness detection method according to claim 1, characterized in that: In the step 2, the time for inflating the airtight testing tool is controlled within 2-8 seconds, and the first set pressure is controlled within 200-350 KPa.

3. The airtightness detection method according to claim 1, characterized in that: The method for judging whether there is a large leak in the test product according to the first detection pressure value is: Determine whether the maximum value of the first detection pressure is less than the preset first detection pressure threshold: if so, it indicates that the test product has a large leak; if not, it indicates that the test product has no large leak; the first detection pressure threshold is set according to the first detection pressure measured by the qualified product under the same inflation condition; or, The ratio of the first detection pressure to the set test pressure is taken as the pressure conversion ratio, and it is determined whether the pressure conversion ratio is less than the preset first pressure conversion ratio threshold: if so, it indicates that there is a large leak in the test product; if not, it indicates that there is no large leak in the test product; the first pressure conversion ratio threshold is set according to the ratio between the detection pressure measured by the qualified product under the same inflation conditions and the set test pressure.

4. The airtightness detection method according to claim 1, characterized in that: In the step 4, the time for filling the airtightness detection tool with the test gas is controlled within 20-30 seconds, and the second set pressure is controlled within 100-350 KPa.

5. The airtightness detection method according to claim 1, characterized in that: In the step 5, the pressure balance time is controlled within 60-90 seconds; in the step 6, the gas leakage time is controlled within 15-20 seconds.

6. The airtightness detection method according to claim 1, characterized in that: In step seven, the method for judging whether the test product has a leak based on the gas leakage volume is as follows: judging whether the gas leakage volume is greater than a preset leakage judgment value: if so, judging that the airtightness test of the test product fails; if not, judging that the airtightness test of the test product passes; the leakage judgment value is set according to the gas leakage volume measured by the qualified product under the same two-stage inflation conditions.

7. An airtightness detection device suitable for the airtightness detection method according to claims 1 to 6, characterized in that: It includes an airtight testing tool and an air circuit system, wherein the air circuit system is connected to the airtight testing tool and is used to fill the airtight testing tool with test gas. The airtight testing tool has a sealed chamber for accommodating a test product, and the sealed chamber has the same appearance as the test product, so that an inflatable interlayer is formed between the sealed chamber and the test product after the test product is placed.

8. The airtightness detection device according to claim 7, characterized in that: The air circuit system comprises a compressed air system, a pressure regulating valve group, an air tightness tester and a filter group which are sequentially connected in series, and the air outlet of the filter group is connected to the air inlet of the air tightness test tool.

9. The airtightness detection device according to any one of claims 7 to 10, characterized in that: The airtight testing tooling includes an upper tooling and a lower tooling that cooperate with each other. A mold locker is provided between the upper tooling and the lower tooling. The mold locker is used to press the upper tooling and the lower tooling together in a sealed manner, and to form a sealed chamber between the upper tooling and the lower tooling for placing the test product.

10. The airtight detection device according to claim 11, characterized in that: The test product is placed in the sealed chamber in an axially horizontal direction; the connection position between the air path system and the airtight testing tool is located at the upper part of the airtight testing tool.

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