Infrared ultrasonic bag integrity leak detector and leak detection method

Abstract

An infrared ultrasonic leak detection method for bag integrity, using an infrared ultrasonic bag integrity leak detector, includes the following steps: S1, suspending the bag to be tested in the test chamber and closing the switch door; filling the bag to be tested with test gas through the first gas path system to a first calibrated pressure, and evacuating the test chamber to a second calibrated pressure through the second gas path system; S2, waiting for the first calibration time, detecting the concentration of test gas in the test chamber through a gas concentration sensor, and determining that the bag to be tested has leaked if the concentration exceeds the calibrated concentration; S3, activating the ultrasonic sensor to scan the surface of the bag to be tested to identify the ultrasonic peak; activating the infrared thermal imaging unit to acquire a thermal image of the surface of the bag to be tested; determining the location of the leak point by combining the ultrasonic peak and the thermal image; S4, filling the test chamber with air through the second gas path system to restore normal pressure, and venting the test gas from the bag to be tested through the first gas path system; opening the switch door and removing the bag to be tested.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and in particular to an infrared ultrasonic bag integrity leak detector and leak detection method. Background Technology

[0002] In single-use biopharmaceutical processes, flexible containers such as single-use storage bags and bioreactors are widely used due to their advantages, including no need for cleaning, low risk of cross-contamination, and flexible switching. However, if these flexible bags leak, it will directly lead to the scrapping of high-value products such as biological agents and instruments, or even the recall of the entire batch. Therefore, the integrity testing of the bags is crucial.

[0003] In existing technologies, commonly used methods for leak detection based on bag integrity mainly include the following: 1. Pressure attenuation method: A certain pressure of gas is filled into the bag, and the pressure drop is monitored. If the pressure drop exceeds the set threshold, it is judged as a leak. However, this method has several problems: (1) The bag film material itself may have a slight "breathing effect" under pressure, which will mask the leak signal and result in insufficient sensitivity. (2) It is easily affected by temperature. For example, the molecular kinetic energy of the gas is converted into internal energy at the moment of inflation, and the temperature inside the bag may rise first and then fall. If the sensor sampling interval is short, it is easy to misjudge the temperature drop as the pressure drop. When there is a 3°C day-night temperature difference in the workshop, it can cause a 2mbar fluctuation, which is equivalent to a 5μm leak signal, thus generating false alarms. It is necessary to extend the stabilization time or add a temperature compensation algorithm. (3) This method can only determine whether the bag is leaking, but cannot locate the leak point.

[0004] 2. Mass extraction method: First, the bag is evacuated, and then the mass of gas leaking from the bag is measured using a precision instrument. The time consumed by this method increases linearly with the bag volume. For large-capacity (e.g., over 200 liters) 3D bags, the pressure needs to be evacuated to ≤1 mbar before stabilization, resulting in a test cycle time of 8-15 minutes, compared to the 3-5 minutes of the pressure decay method, severely impacting production efficiency. Furthermore, this method also cannot pinpoint the leak point.

[0005] 3. Traditional probabilistic methods, such as the dyeing method, involve immersing the bag in methylene blue after vacuuming the outside and observing whether the dye penetrates; or the microbiological method, which involves filling the bag with culture medium and culturing it for several days to observe whether microorganisms invade. These methods directly contaminate or damage the bag itself during the testing process, therefore they are generally only suitable for batch validation or installation qualification (IQ / OQ), and cannot be used for routine, non-destructive re-inspection before product release or customer use. Furthermore, the results of these methods have poor repeatability and traceability, making automation and data-driven management difficult. Summary of the Invention

[0006] In view of this, it is necessary to provide an infrared ultrasonic bag integrity leak detector and leak detection method, which aims to improve detection efficiency and accuracy while achieving precise location of the leak point.

[0007] An infrared ultrasonic bag integrity leak detector, comprising: A sealed test chamber includes a switchable door, and the test chamber is equipped with a suspension device for suspending and fixing the bag to be tested; The first gas path system is detachably connected to the test bag and is used to fill or discharge test gas into the test bag. The second gas path system is connected to the test chamber and is used to evacuate or restore normal pressure inside the test chamber. The sensing system includes a gas concentration sensor disposed in the test chamber, and a plurality of ultrasonic sensors and infrared thermal imaging units disposed in multiple directions on the inner wall of the test chamber. The control system is electrically connected to the first gas path system, the second gas path system, and the sensing system, and is used to control the leak detection process and process the detection data.

[0008] Furthermore, the first gas path system includes: Test gas source; A first air inlet pipe is connected to the test gas source and is used to fill the test bag with test gas. A first air inlet valve is provided on the first air inlet pipe. The first exhaust pipe is used to discharge the test gas inside the test bag. The first exhaust pipe is equipped with a first vacuum pump and a first exhaust valve. The first merging pipeline combines the first intake pipeline and the first exhaust pipeline and connects to the bag to be tested. The first merging pipeline is connected to a first pressure sensor.

[0009] Furthermore, the test gas is nitrogen, the gas concentration sensor is a nitrogen sensor, and the nitrogen sensor is connected to a nitrogen transmitter.

[0010] Furthermore, the nitrogen sensor is located at the top of the test chamber.

[0011] Furthermore, the second gas path system includes: The second exhaust pipe is used to extract air from the test chamber. The second exhaust pipe is equipped with a second vacuum pump and a second exhaust valve. The second air intake pipe is connected to the external environment and is used to fill the test chamber with air to restore normal pressure. The second air intake pipe is equipped with a second air intake valve. The second merging pipe merges the second intake pipe and the second exhaust pipe and connects to the test chamber. The second merging pipe is connected to a second pressure sensor.

[0012] Furthermore, the ultrasonic sensor and the infrared thermal imaging unit correspond one-to-one in each direction. The ultrasonic sensor is an array of ultrasonic probes, and each array of ultrasonic probes is arranged in a ring around an infrared thermal imaging unit.

[0013] Furthermore, the test cavity is roughly rectangular, and each set of array-type ultrasonic probes and infrared thermal imaging units are distributed on the six inner surfaces of the test cavity: top, bottom, front, back, left, and right.

[0014] An infrared ultrasonic leak detection method for bag integrity, using an infrared ultrasonic leak detector as described in any one of claims 1-6, includes the following steps: Step S1: Suspend the bag to be tested in the test chamber and close the switch door; fill the bag to be tested with test gas to the first calibration pressure through the first gas path system, and evacuate the inside of the test chamber to the second calibration pressure through the second gas path system; Step S2: Wait for the first calibration time, and use the gas concentration sensor to detect the concentration of the test gas in the test chamber. If the concentration exceeds the calibration value, it is determined that the bag under test has leaked, and proceed to step S3; otherwise, it is determined that the bag under test is qualified, and proceed to step S4. Step S3: Activate the ultrasonic sensor to scan the surface of the bag to be tested and identify the ultrasonic peak value; activate the infrared thermal imaging unit to acquire a thermal image of the surface of the bag to be tested; determine the location of the leak point by combining the ultrasonic peak value and the thermal image; Step S4: Fill the test chamber with air through the second air path system to restore normal pressure, and discharge the test gas in the test bag through the first air path system; open the switch door and take out the test bag.

[0015] Furthermore, in step S3, all the ultrasonic sensors operate sequentially, and after each ultrasonic sensor stops operating, the next ultrasonic sensor is started after a second calibration interval.

[0016] Furthermore, in step S3, the specific steps of the comprehensive determination include: The scanning signal of the ultrasonic sensor is mapped onto the two-dimensional image acquired by the infrared thermal imaging unit; Mark the location where the ultrasonic peak value meets the calibrated loudness, and mark the location in the thermal imaging where the temperature difference meets the calibrated temperature difference and the abnormal area meets the calibrated area. If the same location is marked in both ultrasonic detection and infrared thermal imaging detection, then the location is determined to be the leak point. Use thermal imaging to pinpoint the leak point.

[0017] The infrared ultrasonic bag integrity leak detector and leak detection method provided by this invention have at least the following beneficial effects: 1. The system employs dual-channel detection using infrared thermal imaging and ultrasonic detection. Through data fusion analysis, it can not only determine whether the bag is leaking, but also accurately locate the leak point, providing strong traceability and direct evidence for subsequent maintenance and quality analysis.

[0018] 2. The leakage situation of the bag is determined by the change in the concentration of the test gas caused by the leakage and the acoustic / thermal imaging signal. The detection results are not sensitive to the temperature fluctuation of the test environment alone, avoiding false alarms caused by the breathing effect and adiabatic expansion of traditional methods. Moreover, it does not require long-term voltage stabilization or complex temperature compensation algorithms, thus improving the reliability and efficiency of detection.

[0019] 3. It can acquire judgment data through sensors in a shorter time, resulting in a shorter overall detection cycle and improved production efficiency.

[0020] 4. The bag is suspended inside the test chamber, and the test process does not contact the inside of the bag, so it will not cause contamination or damage to the bag; the same set of equipment can be adapted to various sizes of bags by adjusting the test parameters, making it highly versatile.

[0021] 5. The entire testing process, including inflation, vacuuming, data acquisition, analysis and result determination, can be completed automatically through program control, which reduces the technical threshold and human error for operators, ensures the consistency of test results, and is easy to integrate into a digital production management system. Attached Figure Description

[0022] Figure 1 This is a perspective view of the housing in the infrared ultrasonic bag integrity leak detector of the first embodiment of the present invention.

[0023] Figure 2 This is a three-dimensional view of the test chamber in the infrared ultrasonic bag integrity leak detector of the first embodiment of the present invention.

[0024] Figure 3 This is a perspective view of the gas path system and gas concentration sensor in the infrared ultrasonic bag integrity leak detector of the first embodiment of the present invention.

[0025] Figure 4 This is a gas path diagram of the gas path system in the infrared ultrasonic bag integrity leak detector of the first embodiment of the present invention.

[0026] Figure 5 This is a flowchart of the infrared ultrasonic bag integrity leak detection method according to the second embodiment of the present invention.

[0027] The parts represented by the numbers in the attached diagram are as follows: 1-Shell; 10-Bag to be tested; 11-Door; 12-Control panel; 13-Feet; 14-Test chamber; 15-Component chamber; 16-Hook; 21-First inlet pipe; 22-First exhaust pipe; 23-First merging pipe; 24-First inlet valve; 25-First vacuum pump; 26-First exhaust valve; 27-First pressure sensor; 31-Second inlet pipe; 32-Second exhaust pipe; 33-Second merging pipe; 34-Second vacuum pump; 35-Second exhaust valve; 36-Second inlet valve; 37-Second pressure sensor; 41-Ultrasonic sensor; 42-Infrared thermal imaging unit; 43-Nitrogen sensor; 44-Nitrogen transmitter. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The technical solutions involved in the present invention are not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1 Please see Figures 1 to 4 The first embodiment of the present invention provides an infrared ultrasonic bag integrity leak detector, which includes a housing 1, a first air path system, a second air path system, a sensing system and a control system.

[0030] like Figure 1 and Figure 2 As shown, the housing 1 is generally rectangular, with an openable and closable door 11 (such as a hinged door or a sliding sealed door) on one side. The outer wall of the housing 1 is provided with a control panel 12 for operation by the operator, and the bottom of the housing 1 is provided with a support leg 13. The internal space of the housing 1 is divided into at least a test chamber 14 and a component chamber 15.

[0031] The test chamber 14 is a sealed box. The switch door 11 is connected to the test chamber 14 so that the operator can put in and take out the bag 10 to be tested. The connection position (such as the door frame) between the test chamber 14 and the switch door 11 is usually equipped with a sealing strip to ensure the sealing performance of the test chamber 14. The component cavity 15 is used to install and accommodate other components of the leak detector, so that the equipment is neat and beautiful and easy to repair and maintain.

[0032] The test chamber 14 is equipped with a suspension device for suspending and fixing the bag 10 to be tested. In a preferred embodiment, the suspension device is a hook 16 disposed on the inner wall of the test chamber 14. The bag 10 to be tested is hung on the hook 16 by its own suspension ring or lug, so that the bag 10 to be tested is suspended in the air, avoiding contact with the inner wall of the chamber and ensuring that the sensor can scan in all directions. The test chamber 14 is preferably rectangular, and its six inner surfaces (top, bottom, front, back, left, and right) provide a flat mounting surface for installing the sensor probe. It is understood that the shape of the test chamber 14 is not limited to this, and it can also be a cylinder or other polyhedron.

[0033] like Figure 3 and Figure 4 As shown, the first gas path system is detachably connected to the filling / venting port of the test bag 10 via a quick-plug interface, and is used to fill or discharge test gas into the test bag 10. Specifically, the first gas path system mainly includes a test gas source (not shown), a first inlet pipe 21, a first exhaust pipe 22, and a first merging pipe 23.

[0034] In this embodiment, the test gas is nitrogen, and the test gas source is an external component, typically a high-pressure nitrogen cylinder with a pump switch or a laboratory nitrogen pipeline. Nitrogen was chosen as the test gas because of its stable chemical properties, moderate cost, and ease of detection by a gas concentration sensor. In other embodiments, inert gases such as helium or argon can also be used.

[0035] The first air inlet pipe 21 is connected to the test gas source and is used to fill the test bag 10 with test gas; the first air inlet pipe 21 is provided with a first air inlet valve 24.

[0036] The first exhaust pipe 22 is connected to the external environment or a waste gas recovery device and is used to discharge the test gas in the test bag 10 after the test is completed. The first exhaust pipe 22 is provided with a first vacuum pump 25 and a first exhaust valve 26 in sequence. The first vacuum pump 25 is used to actively evacuate the gas in the bag and accelerate the discharge speed.

[0037] The first merging pipe 23 is used to merge the first intake pipe 21 and the first exhaust pipe 22, and connect them to the test bag 10 through a main interface; a first pressure sensor 27 is installed on the first merging pipe 23 to monitor the gas pressure in the test bag 10 in real time, so as to determine the end point of the test gas inflation and exhaust.

[0038] The second gas path system is connected to the test chamber 14 and is used to evacuate the sealed test chamber 14 and to fill the test chamber 14 with air after the test to restore normal pressure. Specifically, the second gas path system mainly includes a second intake pipe 31, a second exhaust pipe 32, and a second merging pipe 33.

[0039] The second exhaust pipe 32 is connected to the external environment or a waste gas recovery device to extract air from the test chamber 14; a second vacuum pump 34 and a second exhaust valve 35 are sequentially provided on the second exhaust pipe 32.

[0040] The second air intake pipe 31 is connected to the external environment directly or through external components such as a fan (not shown) to fill the test chamber 14 with air after the test to restore normal pressure; the second air intake pipe 31 is provided with a second air intake valve 36.

[0041] The second merging pipe 33 is used to merge the second intake pipe 31 and the second exhaust pipe 32, and connect them to the test chamber 14 through a main interface; a second pressure sensor 37 is installed on the second merging pipe 33 to monitor the gas pressure in the test chamber 14 in real time, so as to determine the end point of air inflation and the end point of air exhaust.

[0042] In this embodiment, the first intake valve 24, the first exhaust valve 26, the second intake valve 36, and the second exhaust valve 35 are all solenoid valves to achieve high-speed and sensitive on / off control.

[0043] The sensing system includes a gas concentration sensor disposed in the test chamber 14, and a plurality of ultrasonic sensors 41 and infrared thermal imaging units 42 disposed in multiple directions on the inner wall of the test chamber 14.

[0044] like Figure 3 As shown, the gas concentration sensor is used to detect changes in the concentration of the test gas within the test chamber 14 to determine whether there is a leak of the test gas in the test bag 10 after the test chamber 14 is evacuated. When nitrogen is used as the test gas, the gas concentration sensor is a nitrogen sensor 43, which is connected to a nitrogen transmitter 44 to convert the sensor signal into a standard electrical signal for transmission to the control system. The nitrogen sensor 43 is preferably installed on the upper part of the test chamber 14, such as on the top wall of the test chamber 14 in this embodiment. Since nitrogen is slightly less dense than air, if the bag leaks, the leaked nitrogen will naturally rise in the chamber due to buoyancy. Placing the nitrogen sensor 43 on the upper part of the test chamber 14 allows for earlier and more sensitive detection of the increased concentration of the leaking gas, thereby improving the response speed and reliability of the leak detection.

[0045] like Figure 2As shown, the array-type ultrasonic probe and the infrared thermal imaging unit 42 are respectively distributed on the upper, lower, front, rear, left and right inner surfaces of the test cavity 14 to achieve omnidirectional coverage scanning of the bag 10 to be tested.

[0046] The ultrasonic sensor 41 is used to scan the surface of the bag 10 under test to identify ultrasonic peaks. When the bag 10 under test has a through-hole defect larger than micrometers, driven by the internal and external pressure difference (usually tens of Pascals or more), the leaked test gas will be ejected at high speed at the leak, forming a turbulent jet with a Reynolds number Re > 2000. This turbulent shear layer will excite the generation of broadband sound waves, of which the 20kHz to 100kHz frequency band belongs to airborne ultrasound. The ultrasonic signal generated by the leak has a higher sound signal intensity than the ambient background noise at close range, thus providing the prerequisite for the ultrasonic sensor 41 to scan and detect the leak point as a point sound source.

[0047] In this embodiment, the ultrasonic sensor 41 employs a ring-shaped array ultrasonic probe (center frequency 40kHz, -6dB bandwidth 10kHz). Based on theoretical calculations and experimental measurements, for a leak with a diameter of 0.1mm, the probe can receive an ultrasonic signal of approximately 58dB SPL (relative to 20μPa) at a detection distance of 10cm. This signal strength is more than 15dB higher than the ambient background noise, thus enabling clear identification and location.

[0048] The infrared thermal imaging unit 42 is used to acquire thermal images of the surface of the bag 10 under test. According to the Joule-Thomson effect, when high-speed gas expands adiabatically from inside the bag through a leak into the low-pressure environment of the cavity, the gas temperature will instantly drop by 0.3℃-2℃. For gases at room temperature, this effect will create a localized low-temperature region outside the leak, i.e., a "cold spot." Conversely, if the bag stores a high-temperature (e.g., 60℃) or low-temperature (e.g., 4℃) medium, the leaked gas or medium itself will form a thermal conduction bypass, creating a hot spot or cold spot relative to the background around the leak.

[0049] In this embodiment, a long-wave infrared thermal imager with 320×256 pixels and NETD (noise equivalent temperature difference) ≤30 mK is used. At a working distance of approximately 30 cm, its spatial resolution is 0.5 mm. The temperature gradient at the leak point and the background temperature difference satisfy the following relationship: ΔT = (P·n·C p ) / (2πλr)·exp(-r 2 / 4αt) In the formula, ΔT is the temperature difference between the leak point and the background, P is the mass flow rate, n is the Joule-Thomson coefficient of the test gas, and C pThe specific heat capacity at constant pressure of the gas is used for testing, where λ is the thermal conductivity of air, α is the thermal diffusivity of air, r is the distance from the observation point to the leak point, and t is the leak time.

[0050] According to theoretical calculations and experimental measurements, under typical experimental conditions of a leak diameter of 1 μm and an internal pressure of 0.2 MPa, a temperature difference of about 0.8°C can be generated at the leak, which is sufficient to be captured by an infrared thermal imager.

[0051] Furthermore, the ultrasonic sensor 41 and the infrared thermal imaging unit 42 are in one-to-one correspondence in each direction, that is, each ring-shaped array ultrasonic probe is arranged around an infrared thermal imaging unit 42, so that the signal center of each ring-shaped array ultrasonic probe coincides with the infrared thermal imaging unit 42 in the same direction. Therefore, in subsequent data processing, ultrasonic signals and infrared thermal imaging signals in the same area and direction can be easily correlated and fused.

[0052] The control system (not shown in the figure) is typically a PLC or industrial computer, electrically connected to all valves, vacuum pumps, and pressure sensors in the first and second gas path systems, as well as all sensors and transmitters in the sensing system. The control system has a pre-set leak detection scheme and algorithm (including parameters such as calibration pressure, calibration duration, and detection threshold), capable of automatically executing the entire leak detection process. This includes sequentially controlling the start and stop of each valve and vacuum pump, collecting and processing pressure and concentration data, triggering and analyzing ultrasonic and infrared signals, and finally outputting a test conclusion indicating whether a leak exists (i.e., whether the bag 10 under test is qualified) and the coordinates of the leak location.

[0053] Example 2 Please see Figure 5 The second embodiment of the present invention provides an infrared ultrasonic leak detection method for bag integrity, comprising the following steps: Step S1, Test preparation: Suspend the bag to be tested 10 in the test chamber 14 and close the switch door 11; fill the bag to be tested 10 with test gas through the first gas path system to the first calibration pressure, and evacuate the inside of the test chamber 14 to the second calibration pressure through the second gas path system; Specifically, in this embodiment, step S1 includes the following sub-steps: S11. The operator connects the bag to be tested 10 (such as a disposable biological storage bag) to the first combined pipeline 23 interface of the first gas path system through its port, and suspends it on the hook 16 inside the test chamber 14. Close the switch door 11 to seal the chamber and start the test program.

[0054] S12. The control system automatically closes the second inlet valve 36, the second exhaust valve 35, and the first exhaust valve 26, and opens the first inlet valve 24. Nitrogen gas is introduced into the test bag 10 through the first inlet pipe 21. The first pressure sensor 27 monitors the pressure inside the test bag 10 in real time. When the preset first calibration pressure is reached, the first inlet valve 24 and the pump switch of the external test gas source are closed.

[0055] Specifically, the first calibration pressure can be set according to the type of test gas, bag specifications and material, usually in the range of 50-150 kPa, and preferably 100 kPa in this embodiment.

[0056] S13. The control system automatically opens the second exhaust valve 35 and starts the second vacuum pump 34 to evacuate the inside of the test chamber 14. The second pressure sensor 37 monitors the pressure inside the test chamber 14, and when the preset second calibration pressure is reached, it closes the second exhaust valve 35 and the second vacuum pump 34.

[0057] Specifically, the second calibration pressure can be set in the range of -5kPa to -50kPa, and in this embodiment, -10kPa is preferred.

[0058] Furthermore, in step S12, after the first pressure sensor 27 detects that the pressure inside the bag 10 under test has reached the first calibrated pressure and turns off the pump switch, the pressure is stabilized for a period of time (e.g., 30s) before the first air inlet valve 24 or the second air inlet valve 36 is turned off; in step S13, after the second pressure sensor 37 detects that the pressure inside the bag 10 under test has reached the second calibrated pressure and turns off the second vacuum pump 34, the pressure is stabilized for a period of time (e.g., 30s) before the second air inlet valve 36 is turned off, so as to ensure that the gas in the bag and cavity is fully expanded and stabilized, and to avoid false alarms.

[0059] Step S1 establishes a significant pressure difference between the bag to be tested 10 and the test chamber 14, causing gas to leak from the bag into the chamber when a leak is present.

[0060] Step S2, Leakage Determination: After waiting for the first calibration time, the gas concentration in the test chamber 14 is detected by the gas concentration sensor. If the concentration exceeds the calibration concentration, the bag to be tested 10 is determined to have leaked, and the process proceeds to step S3; otherwise, the bag to be tested 10 is determined to be qualified, and the process proceeds to step S4. Specifically, in this embodiment, step S2 includes the following sub-steps: S21. The control system waits for a preset first calibration time (e.g., 5 minutes). During this period, if there is a leak in the bag, nitrogen will leak into the test chamber 14 through the leak, causing the concentration of the test gas in the test chamber 14 to increase.

[0061] S22. The control system reads the nitrogen concentration values ​​measured by the nitrogen sensor 43 and the nitrogen transmitter 44, and determines whether the bag 10 under test has leaked. If the detected nitrogen concentration does not exceed the preset calibration concentration, the bag 10 under test is deemed qualified, and the process jumps directly to step S4 for completion. If the nitrogen concentration exceeds the calibration concentration, the bag is deemed to have leaked, and the process proceeds to step S3 for leak location.

[0062] Specifically, since the bag material itself may also have gas leakage, the calibration concentration should be set through multiple measurements for different materials and processes, representing the maximum allowable background leakage rate.

[0063] Step S3, Leakage point location: Activate the ultrasonic sensor 41 to scan the surface of the bag 10 to be tested and identify the ultrasonic peak value; activate the infrared thermal imaging unit 42 to acquire the thermal image of the surface of the bag 10 to be tested; determine the location of the leak point by combining the ultrasonic peak value and the thermal image. Specifically, in this embodiment, step S3 includes the following sub-steps: S31. The control system automatically starts the ultrasonic sensor 41 to scan the surface of the bag and identify the ultrasonic peak value.

[0064] Furthermore, all the ultrasonic sensors 41 operate sequentially. After each ultrasonic sensor 41 stops operating, the next ultrasonic sensor 41 is activated after a second calibration interval, to avoid signal cross-interference caused by multiple probes emitting ultrasonic waves simultaneously. In this embodiment, following the order of the bag 10 under test from top to bottom to front to back to left to right, one array ultrasonic probe is controlled to emit ultrasonic waves and collect data for 20ms before stopping. After another 20ms interval, the next probe is activated.

[0065] S32, The control system automatically starts all infrared thermal imaging units 42 in all directions to start working simultaneously and collect thermal images of the surface of the bag 10 to be tested.

[0066] S33. The control system fuses the data collected by the two sensors to comprehensively determine the location of the leak.

[0067] Specifically, in this embodiment, step S33 includes the following sub-steps: S331. The scanning signal (usually a one-dimensional scan line or point cloud data) of the ultrasonic sensor 41 is mapped and registered onto the two-dimensional image acquired by the infrared thermal imaging unit 42. Since the ultrasonic sensor 41 and the infrared thermal imaging unit 42 in this embodiment correspond one-to-one in each direction, and the signal center of each ring-shaped array ultrasonic probe coincides with the infrared thermal imaging unit 42 in the same direction, there is no need to perform complex processing on the ultrasonic signal and the infrared thermal image signal.

[0068] S332. Mark the location where the ultrasonic peak value meets the calibrated loudness, and mark the location in the thermal imaging where the temperature difference meets the calibrated temperature difference and the abnormal area meets the calibrated area. If the same location is marked in both ultrasonic detection and infrared thermal imaging detection, then the location is determined to be the leak point. Specifically, in this embodiment, a score of 1 is awarded for locations where the ultrasonic peak exceeds the background noise by 15 dB, and another score is awarded for locations in the thermal imaging image where the temperature difference is greater than 0.4℃ and the abnormal area is less than or equal to 3 pixels. A score of 2 indicates a leak. This dual-channel ultrasonic-infrared scoring method provides accurate positioning and effectively avoids false alarms caused by environmental noise and other errors.

[0069] S333. Take a thermal imaging image to pinpoint the leak point. In this embodiment, the positioning accuracy can reach ±0.5mm.

[0070] Step S4: End the test: Fill the test chamber 14 with air through the second air circuit system to restore normal pressure, and discharge the test gas in the test bag 10 through the first air circuit system; open the switch door 11 and take out the test bag 10.

[0071] Specifically, in this embodiment, step S4 includes the following sub-steps: S41. The control system automatically opens the second air intake valve 36 (and any external components such as a fan) to fill the test chamber 14 with air. When the second pressure sensor 37 shows that the pressure inside the test chamber 14 has returned to normal pressure, the second air intake valve 36 is closed.

[0072] S42. The control system automatically opens the first exhaust valve 26 and the first vacuum pump 25 to extract nitrogen gas from the bag 10 to be tested. When the first pressure sensor 27 shows that the bag is under negative pressure, it indicates that the gas has been basically emptied, and the first exhaust valve 26 and the first vacuum pump 25 are closed.

[0073] S43. The operator opens the switch door 11 of the test chamber 14, takes out the bag to be tested 10, and the entire leak test process is completed.

[0074] In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0076] In the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

Claims

1. An infrared ultrasonic bag integrity leak detector, characterized in that, include: A sealed test chamber includes a switchable door, and the test chamber is equipped with a suspension device for suspending and fixing the bag to be tested; The first gas path system is detachably connected to the test bag and is used to fill or discharge test gas into the test bag. The second gas path system is connected to the test chamber and is used to evacuate or restore normal pressure inside the test chamber. The sensing system includes a gas concentration sensor disposed in the test chamber, and a plurality of ultrasonic sensors and infrared thermal imaging units disposed in multiple directions on the inner wall of the test chamber. The control system is electrically connected to the first gas path system, the second gas path system, and the sensing system, and is used to control the leak detection process and process the detection data.

2. The infrared ultrasonic bag integrity leak detector according to claim 1, characterized in that, The first air path system includes: Test gas source; A first air inlet pipe is connected to the test gas source and is used to fill the test bag with test gas. A first air inlet valve is provided on the first air inlet pipe. The first exhaust pipe is used to discharge the test gas inside the test bag. The first exhaust pipe is equipped with a first vacuum pump and a first exhaust valve. The first merging pipeline combines the first intake pipeline and the first exhaust pipeline and connects to the bag to be tested. The first merging pipeline is connected to a first pressure sensor.

3. The infrared ultrasonic bag integrity leak detector according to claim 1, characterized in that: The test gas is nitrogen, the gas concentration sensor is a nitrogen sensor, and the nitrogen sensor is connected to a nitrogen transmitter.

4. The infrared ultrasonic bag integrity leak detector according to claim 3, characterized in that: The nitrogen sensor is located at the top of the test chamber.

5. The infrared ultrasonic bag integrity leak detector according to claim 1, characterized in that, The second air path system includes: The second exhaust pipe is used to extract air from the test chamber. The second exhaust pipe is equipped with a second vacuum pump and a second exhaust valve. The second air intake pipe is connected to the external environment and is used to fill the test chamber with air to restore normal pressure. The second air intake pipe is equipped with a second air intake valve. The second merging pipe merges the second intake pipe and the second exhaust pipe and connects to the test chamber. The second merging pipe is connected to a second pressure sensor.

6. The infrared ultrasonic bag integrity leak detector according to claim 1, characterized in that: The ultrasonic sensor and the infrared thermal imaging unit are in one-to-one correspondence in each direction. The ultrasonic sensor is an array of ultrasonic probes, and each of the array of ultrasonic probes is arranged in a ring around an infrared thermal imaging unit.

7. The infrared ultrasonic bag integrity leak detector according to claim 6, characterized in that: The test cavity is roughly rectangular, and each set of array-type ultrasonic probes and infrared thermal imaging units are distributed on the six inner surfaces of the test cavity: top, bottom, front, back, left, and right.

8. A method for detecting leaks in an infrared ultrasonic bag, characterized in that, Using the infrared ultrasonic bag integrity leak detector as described in any one of claims 1-7, the procedure includes the following steps: Step S1: Suspend the bag to be tested in the test chamber and close the switch door; fill the bag to be tested with test gas to the first calibration pressure through the first gas path system, and evacuate the inside of the test chamber to the second calibration pressure through the second gas path system; Step S2: Wait for the first calibration time, and use the gas concentration sensor to detect the concentration of the test gas in the test chamber. If the concentration exceeds the calibration value, it is determined that the bag under test has leaked, and proceed to step S3; otherwise, it is determined that the bag under test is qualified, and proceed to step S4. Step S3: Activate the ultrasonic sensor to scan the surface of the bag to be tested and identify the ultrasonic peak value; activate the infrared thermal imaging unit to acquire a thermal image of the surface of the bag to be tested; determine the location of the leak point by combining the ultrasonic peak value and the thermal image; Step S4: Fill the test chamber with air through the second air path system to restore normal pressure, and discharge the test gas in the test bag through the first air path system; open the switch door and take out the test bag.

9. The infrared ultrasonic bag integrity leak detection method according to claim 8, characterized in that: In step S3, all the ultrasonic sensors work sequentially. After each ultrasonic sensor stops working, the next ultrasonic sensor is started after a second calibration interval.

10. The infrared ultrasonic bag integrity leak detection method according to claim 8, characterized in that, In step S3, the specific steps of the comprehensive determination include: The scanning signal of the ultrasonic sensor is mapped onto the two-dimensional image acquired by the infrared thermal imaging unit; Mark the location where the ultrasonic peak value meets the calibrated loudness, and mark the location in the thermal imaging where the temperature difference meets the calibrated temperature difference and the abnormal area meets the calibrated area. If the same location is marked in both ultrasonic detection and infrared thermal imaging detection, then the location is determined to be the leak point. Use thermal imaging to pinpoint the leak point.

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