Early leakage detection method and apparatus configured to implement same
An early leak detection method that applies a pressure differential to the test object and compares it with a reference extreme value solves the problems of speed, accuracy and repeatability of leak detection in industrial environments, enabling early detection of leaks and shortening test time.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-23
- Publication Date
- 2026-03-27
AI Technical Summary
In industrial environments, existing leak detection methods struggle to achieve rapid, accurate, and repeatable sealing control under complex conditions, especially on assembly lines or production lines, where environmental parameters and disturbances affect the real-time tracking and repeatability of pressure changes.
An early leak detection method is adopted. By applying a pressure difference to the test object, measuring relevant physical quantities, and comparing them with the preset first and second reference extreme values, the presence or absence of a leak can be determined in advance, thus shortening the test cycle time.
This technology enables early detection of leaks before the test cycle ends, reducing test time by 10% to 70%, improving detection accuracy and repeatability, and ensuring continuous operation of the production line.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of leak detection methods for the containment control of objects, in particular to leak detection methods based on pressure differential. The present application also relates to leak detection devices configured to implement the above-mentioned methods.
[0002] The present application also relates to a filtering method for leak test cycles of a type of object, for building a database able to determine at least one reference value related to the leak test of said type of object, in particular for the early leak detection method of the present application. BACKGROUND
[0003] Various systems and methods for detecting leaks are known, such as the tracer gas method, the soap bubble method, etc. In the present application, the present application more specifically relates to leak detection based on pressure differential (or variation thereof).
[0004] When leak detection is performed using the pressure differential method, the test object whose containment level is to be controlled is subjected to a controlled pressure differential. In particular, this means that a pressure variation (positive or negative) is generated in a specific internal volume of the object (direct method) or in a closed volume surrounding the object (indirect method), for example with respect to the outside of the object.
[0005] After a preset time period, the pressure variation in the specific volume is measured over a preset time period, in order to determine whether the object has a leak, and sometimes to quantify the degree of leak of the test object.
[0006] In fact, a leak causes a pressure variation over a specific time period, and in particular the pressure variation per unit of time can be associated with the degree of leak, for example through the following mathematical relationship: where F is the leak rate, usually expressed in standard cubic centimetres per minute (or scc / min); ΔΡ is the pressure variation measured in the relevant (or specific) volume, expressed in Pascals (Pa); Δt is the time period over which the pressure variation ΔΡ is measured (expressed in seconds); V is the relevant volume to be considered (for example the internal volume of the object), usually expressed in cubic centimetres (cm 3 ); k is a multiplicative constant (expressed in Pa -1 ). It should be noted that the leak rate can be expressed in other ways, for example in the form of mass flow. Therefore, the formula relating the leak rate to a certain physical quantity can have various forms depending on the measurement method used and the physical quantity studied.
[0007] Therefore, it is possible to determine whether the object, or any of its sub-components, has a leak and to determine its containment level (or degree of leak), regardless of the type of object.
[0008] The test object can be an electronic device, a package, a container, etc. The tolerance requirements for the level of tightness (or degree of leakage) can therefore vary greatly depending on the test object itself, its volume, shape and / or function.
[0009] However, when testing the tightness of an object, environmental parameters and / or temporary disturbances of various kinds can make it difficult to track the pressure variations in real time and / or limit the repeatability of such measurements.
[0010] This problem is particularly acute when detecting leaks in an industrial environment, such as a factory, since the temperature and / or pressure in such an environment can vary spatially and / or temporally depending on the operation of the test object or the operation in the vicinity of the leak detection device.
[0011] In addition, the detection device can be designed to test the tightness of objects on an assembly or production line. In this case, it is necessary to have a tightness control that is as fast, accurate and repeatable as possible so as not to disturb (or slow down) the assembly or production line. SUMMARY
[0012] The present invention aims to provide, with the aid of a leak detection device, a new method for early detection of leaks in an object, in order to solve at least one of the problems mentioned above, the method comprising the following steps: - applying a pressure differential to at least one part of the test object or to a closed space surrounding the test object, the pressure differential being respectively relative to the outside of the test object or to at least one part of the test object; - measuring, during a test cycle of predetermined duration, a physical quantity related to the degree of leakage in at least one part of the test object or in a closed space surrounding the test object; - comparing the measured value of the physical quantity with a first reference extreme value; - determining whether the test object has a leak or not, as a function of the comparison between the measured value and the first reference extreme value; - interrupting the test cycle if it is determined that the test object has a leak.
[0013] The method according to the invention thus makes it possible to determine, in advance (i.e. before the end of the full duration of the test cycle), whether the test object has a leak or not, or whether the degree of leakage is above a predetermined threshold. According to experimental observations, the duration of the test cycle can be reduced by between 10% and 70% using the method according to the invention.
[0014] According to one possible feature, the method comprises the following step: - comparing the measured value of the physical quantity with a second reference extreme value; - Based on the comparison result between the measured value and the second reference extreme value, determine whether the test object has no leakage; - If it is determined that there is no leakage in the test object, then the test loop is interrupted.
[0015] Setting a second reference extreme value can frame the measured value, wherein the first reference extreme value is used to determine in advance whether the object has a leak, and the second reference extreme value is used to determine in advance whether the object has no leak. Therefore, a shorter average test time can be obtained to determine whether the object has a leak or whether it meets the sealing requirements defined above for the type of object under consideration.
[0016] According to another possible feature, a first reference extreme value and a second reference extreme value define a reference value interval, wherein the measured value is compared with the reference interval, and once the measured value exceeds the reference interval, it can be determined whether the object has a leak; as long as the measured value is within the boundary of the reference interval, the leak test continues until the test cycle is completed.
[0017] According to another possible characteristic, the first reference extremum R MAX R is defined by the following formula: MAX =R L +M C +k1×I D ; Among them, R L M is the leakage threshold. C I is a measure of the central tendency of the compensation values. D is the dispersion index, and k1 is a positive real constant.
[0018] According to another possible characteristic, the second reference extremum R MIN R is defined by the following formula: MIN =R L +M C -k2×I D ; Among them, R L M is the leakage threshold. C I is a measure of the central tendency of the compensation values. D is the dispersion index, and k2 is a positive real constant.
[0019] It should be noted that the leakage threshold R L Corresponding to a set (or preset) leakage value, this leakage value is used to determine whether the object is sealed or leaking. In a typical test cycle scenario (i.e., without using early leak detection methods), after a preset time period, and without considering instantaneous phenomena that might affect the measurement results, the change in physical quantity measured per unit time will (directly or indirectly) correspond to and determine the degree of leakage of the test object, and is subsequently compared with the leakage threshold R. LThe objects are compared to determine whether they are sealed.
[0020] It should also be noted that the measured value of the physical quantity is, for example, determined as the degree of leakage or leakage rate, in units such as Pascals per second (Pa / s). However, this measurement value may be subject to offsets, for example, due to the influence of environmental parameters (temperature, humidity, season, etc.), which may vary within a day or a year. Therefore, when determining the first reference extreme value and / or the second reference extreme value, these environmental parameters must be considered and compensated for in order to determine as accurately as possible whether the test object has a leak, whether its leakage degree is higher than a preset threshold, and / or conversely, whether the test object can be considered sealed (or at least the leakage degree is lower than the preset value or leakage threshold).
[0021] According to another possible feature, the central tendency measure and dispersion index are determined based on multiple tests on objects of the same kind as the test object (i.e., the same or similar objects).
[0022] Advantageously, the measures of central tendency and the index of dispersion are empirical values, based on a large number of identical or structurally similar objects, and / or on the performance of these objects in leak detection methods. This design aims to determine the measures of central tendency and the index of dispersion as accurately as possible, ensuring that the method of the present invention can determine in advance with high precision and accuracy whether the test object is leaking or not.
[0023] According to another possible characteristic, the measure of central tendency is the arithmetic mean or median, while the measure of dispersion is the standard deviation or interquartile range, respectively.
[0024] Depending on the distribution of the possible measured values of the physical quantity, the measure of central tendency is the arithmetic mean or median, while the measure of dispersion is the standard deviation or interquartile range, respectively.
[0025] Specifically, when the distribution of the measured values of the physical quantity is normally distributed, that is, the statistical distribution of the values conforms to a normal distribution, the measure of central tendency is the arithmetic mean, and the measure of dispersion is the standard deviation. Conversely, if the distribution of the measured values of the physical quantity is not normally distributed, the measure of central tendency is the median, and the measure of dispersion is the interquartile range.
[0026] According to another possible characteristic, the constants k1 and k2 are equal to each other, and the constants k1 and k2 are between 1 and 5, preferably equal to 3.
[0027] The values of constants k1 and k2 set the confidence level for determining whether an object has a leak or is sealed. Generally, higher values of k1 and k2 result in more accurate methods, but at the cost of reducing test cycle time. It should be noted that higher values of k1 and k2 mean that transient phenomena (such as airflow, human intervention, etc.) are considered or have less impact on the early determination results, but again, this sacrifices the time reduction effect of the method.
[0028] According to another possible feature, if the measured value of the physical quantity at the start of the test is substantially equal to one of the last few measured values of the previous test cycle (preferably the last measured value of the previous test cycle, wherein the selected measured value must be sufficient to represent the measured value at the end of the test cycle), then the comparison of the measured value with one or more extreme values is interrupted, and the test cycle continues until completion, at which point the degree of leakage is determined and compared with a preset threshold.
[0029] In industrial environments, such as production lines, various unexpected situations may occur during testing, resulting in the same object being tested twice. In such cases, it is necessary to discontinue early leak detection methods and allow the test cycle to complete completely to determine whether the test object has a leak, or whether the degree of leakage exceeds a preset threshold (or the leak threshold R). L This is especially true because the test object is already in a stable state, and its measured value can no longer be effectively compared with the reference extreme value.
[0030] According to another possible feature, the method includes the following steps: - Calculate a function based on two different measurements of the physical quantity; - Compare the calculated function with the first reference extremum; - Based on the comparison result between the calculation function and the first reference extreme value, either continue to execute the early leak detection method or complete the test cycle, accompanied by, for example, an alarm indicating a fault.
[0031] Based on two measurements of the physical quantity, either continuous or discontinuous but distinct, a function is calculated and compared with a reference function to determine whether the test cycle (and leakage testing of the object) is proceeding normally and without any faults that could cause the early leakage detection method to fail. Advantageously, the calculated function is related to or indicates a parameter of the curve shape of the physical quantity, i.e., related to the time evolution of the measured value of the physical quantity.
[0032] Otherwise, discontinue the early leak detection method and complete the test cycle, while issuing an alarm indicating a malfunction so that the operator responsible for monitoring the leak detection method is aware that the object needs to be inspected and may be retested later (otherwise, the object may be deemed not to meet the preset sealing requirements).
[0033] Based on another possible feature, the calculated function is compared with the second reference extremum function; if the comparison result of the calculated function and the second reference extremum function is true, the early leakage detection method continues to be executed; otherwise, the test cycle is completed, and for example, an alarm indicating a fault is triggered.
[0034] Setting first and second reference extreme values can define an interval within which the calculated function is considered accurate or normal, and there are no faults that would cause the leak test to fail.
[0035] According to another possible characteristic, the first reference extremum function is calculated by the following formula: F MAX =F m +k3×I F ; Among them, F m To calculate the measure of central tendency of the function, I F k3 is a positive real constant and represents the dispersion index relative to the computation function.
[0036] According to another possible characteristic, the second reference extremum function is calculated by the following formula: F MIN =F m -k4×I F ; Among them, F m To calculate the measure of central tendency of the function, I F k4 is a positive real constant and is a measure of the dispersion relative to the computational function.
[0037] As described above, the central tendency measure of the calculated function is either the arithmetic mean or the median (for the function), while the dispersion measure of the calculated function is either the standard deviation or the interquartile range. The choice of the type of central tendency measure and the type of dispersion measure advantageously depends on the distribution type of the calculated function (normal or non-normal).
[0038] Furthermore, the constants k3 and k4 are advantageously equal to each other; for example, their values are at least 2, preferably at least 3, 4, or 5, depending on the desired level of precision or accuracy. It should be noted that the higher the values of k3 and k4, the less transient phenomena (such as airflow, human intervention, etc.) are taken into account or have an impact on the early determination results, but this will sacrifice the time reduction effect brought about by the method.
[0039] According to another possible feature, the calculation function is the difference and / or ratio between two measured values of the physical quantity.
[0040] Advantageously, based on two measurements of the physical quantity, which may be continuous or discontinuous but distinct, the calculated function is related to the derivative of the curve or the time evolution of the physical quantity's measurements.
[0041] This invention also relates to a method for screening leakage test cycles for a specific type of test object, used to construct a database capable of determining at least one reference value related to leakage testing of that type of object, particularly for the early leakage detection method of this invention described above. A test cycle includes measuring a physical quantity related to the degree of leakage at least one part of the test object or within an enclosed space surrounding the test object. The screening method includes at least the following steps: - The difference between the measured values of physical quantities at the beginning and end of a test cycle is called the total difference; - Compare the total difference with a reference total difference, and then optionally determine whether the test period can be included in the database to determine at least one reference value.
[0042] By calculating the difference between the physical quantity measurements at the beginning and end of a test cycle, the screening method described in this invention can quickly eliminate all abnormal leakage test cycles, thereby avoiding the generation of a database that does not conform to the normal and / or average test conditions of the object.
[0043] It should be noted that the start and end of the test period refer to the representative values of the physical quantities measured at the beginning and end of the test; these values can be values measured at a specific point in time (e.g., after their stability and representativeness have been empirically determined), or they can be the average of the first and last measurements.
[0044] Based on one possible characteristic of the screening method, the reference value for the total difference is a measure of central tendency calculated from the testing period of the database.
[0045] Advantageously, the central tendency measure and dispersion index are empirical values, based on a large number of identical or structurally similar objects, and / or on the performance of these objects in the leak detection method. The aim of this design is to determine the central tendency measure and dispersion index as accurately as possible, ensuring that the screening method can generate a database that effectively filters test cycles and obtains reference values to ensure the proper functioning of the aforementioned early leak detection method.
[0046] According to another possible feature of the screening method, the dispersion index is a reference value for the total difference, calculated from the testing period of the database.
[0047] According to another possible feature of the screening method, the comparison of the total difference over the test period is achieved by verifying whether the total difference is within the interval defined by the calculated central tendency measure and dispersion index.
[0048] According to another possible feature of the screening method, the central tendency measure of the total difference is the arithmetic mean or the median, while the relevant dispersion measure corresponds to the standard deviation or the interquartile range, respectively.
[0049] Depending on the distribution type of the possible measured values (normal or non-normal) and the total difference, the central tendency measure of the total difference is the arithmetic mean or median, while the corresponding dispersion measures are the standard deviation or interquartile range, respectively.
[0050] According to another possible feature of the screening method, the method further includes the following steps: - Calculate at least two differences between consecutive different measurements of a physical quantity within a test period; these are called intermediate differences. - Compare each of the intermediate differences with a corresponding reference value, wherein each reference value corresponds one-to-one with each intermediate difference; Optionally, it can then be determined whether the test period can be included in the database for the purpose of determining at least one reference value.
[0051] Advantageously, by accumulating multiple judgment criteria, it is possible to accurately assess the relevance of the test cycle included in the database.
[0052] According to another possible feature of the screening method, the reference value for the intermediate difference is a measure of central tendency calculated from the testing period of the database.
[0053] According to another possible feature of the screening method, the dispersion index for each intermediate difference reference value is calculated from the test period of the database.
[0054] According to another possible feature of the screening method, the comparison of intermediate differences in the test period is achieved by verifying whether each intermediate difference is within the interval defined by the corresponding calculated central tendency measure and dispersion index.
[0055] According to another possible feature of the screening method, the central tendency measure of each intermediate difference is the arithmetic mean or median, while the relevant dispersion measure corresponds to the standard deviation or interquartile range, respectively.
[0056] Depending on the distribution type of the possible measurements of the intermediate differences (normal or non-normal), the central tendency measure for each intermediate difference is the arithmetic mean or the median, while the corresponding dispersion measures are the standard deviation or the interquartile range, respectively.
[0057] According to another possible feature of the screening method, the method further includes the following steps: - Compare the physical quantity measurement value at the beginning of the current test cycle with the physical quantity measurement value at the end of the previous test cycle, wherein the test cycle is a continuous test cycle; - Determine whether the current test period can be included in the database to determine at least one reference value; wherein, if the two sets of measurements are substantially equal, the test period is not included in the database.
[0058] Advantageously, by examining multiple parameters, the relevance of test cycle entries into the database can be determined, with the aim of avoiding duplicate testing of the same object. In this scenario, it is necessary to avoid entering the same object into the database for two test cycles, thereby ensuring the relevance of the constructed database.
[0059] According to another possible feature of the screening method, the comparison of physical quantity measurements between two consecutive test cycles is achieved based on a central tendency measure and a dispersion index associated with each measurement.
[0060] According to another possible feature of the screening method, the measure of central tendency used for the comparison is the arithmetic mean or median, while the measure of dispersion associated with the comparison of measurements between two consecutive test periods is the standard deviation or interquartile range.
[0061] The present invention also relates to a leak detection device configured to perform the above-described early leak detection method.
[0062] The present invention also relates to an electronic device, such as a computer, or a leak detection device, configured to perform the above-described leak test cycle screening method. Attached Figure Description
[0063] The invention will be better understood through the following description of specific embodiments, and its other objects, details, features, and advantages will become clearer. The embodiments are merely illustrative and not restrictive; relevant descriptions are based on the accompanying drawings, which are described below (in the drawings): Figure 1 , denoted as [ Figure 1 [This is a highly simplified schematic diagram of the leak detection device described in this invention;] Figure 2 , denoted as [ Figure 2 ], to show the passage Figure 1 A graph illustrating pressure changes during leak detection using the device shown. Figure 3 , denoted as [ Figure 3 [The following is a flowchart illustrating the leakage detection method of the present invention;] Figure 4 , denoted as [ Figure 4 ]. Detailed Implementation
[0064] [ Figure 1 This is a highly simplified schematic diagram of a leak detection device 1 used to test the sealing performance of an object 10. The test object can be any object whose sealing performance needs to be tested: packaging, heat exchangers, mobile phones, automotive power batteries, etc.
[0065] Therefore, the device 1 includes: - A pressurization or vacuum system 5 is used to control the characteristic volume relative to the test object 10, that is, the characteristic volume can be the internal volume of the test object (direct method) or the enclosed volume around the object (indirect method). - A first pressure sensor 7 is configured to measure pressure changes in the characteristic volume, and the sensor 7 is capable of detecting the airtightness of the test object 10; - A second pressure sensor 17, optionally configured to measure the pressure applied to the characteristic volume by the pressurization or vacuum system 5; - A tracheal connector 11, such as a pipe or hose, is configured to connect the pressurization system 5 to the test object 10 and the reference 13; - Electronic unit 15, such as electronic circuit, is connected to each of the pressure sensors 7, 17 and is configured to acquire pressure values measured by the sensors 7, 17.
[0066] Advantageously, the pressurization or vacuum system 5 includes a pressure (or depressurization) source 51, which may be a supply source for, for example, a pump, compressor, compressed air or compressed gas.
[0067] The first pressure sensor 7 is preferably a differential pressure sensor, while the second pressure sensor 17 is advantageously an absolute pressure sensor. In an embodiment not shown, the first pressure sensor 7 is an absolute pressure sensor, and the leak detection device does not include a reference element 13.
[0068] Will be through [ Figure 1 The leakage detection performed on object 10 by the device 1 shown is considered as one test cycle C. L The testing cycle consists of four main steps, as detailed below. Figure 2 As shown: Filling step I: Compressed air (or any gas, preferably an inert gas, such as nitrogen) is filled into the characteristic volume of the test object to increase the pressure to the target pressure value P1; Stabilization Step II: After the characteristic volume of the test object is under pressure, it needs to be restored to a state of thermal and mechanical equilibrium. This usually takes a preset time, also known as the stabilization time, in order to reduce the interference of transient phenomena on leakage measurement. Test Step III: At the end of this step, obtain the measured value of the pressure change in the characteristic volume over time, and then determine the degree of leakage of the test object; Emptying step IV: Restore the pressure characteristic volume of the test object to ambient pressure.
[0069] It should be noted that leak detection can also be performed in a vacuum environment (or low-pressure conditions). That is, step I is no longer about increasing the pressure, but about reducing the pressure within the characteristic volume of the test object to a preset value. Steps II and III remain unchanged, while step IV involves increasing the pressure within the test object to a pressure value that matches the ambient pressure. Therefore, in pressure-based and vacuum-based leak detection procedures, step I (filling) and step IV (emptying) can be considered as "inverted" relationships.
[0070] This invention is a differential pressure-based early leakage detection method based on device 1, which has significant advantages, especially in terms of the test cycle C. L In the stabilization step II and / or testing step III (described in detail below). One of the objectives of this invention is to shorten the testing cycle time and achieve leak detection as quickly as possible, thereby determining as early and accurately as possible whether the test object has a leak.
[0071] The method described in this invention is specifically as follows: Figure 3 As shown, it includes the following steps: S1 connection: Connect the test object 10 to the leakage detection device 1; S2 Pressure Regulation and Differential Pressure Establishment: Change the pressure inside at least a part of the test object or in the enclosed space around the test object 10, and establish a differential pressure between a part of the test object 10 and the outside of the object, or between the enclosed space around the test object 10 and at least a part of the test object; S3 Physical quantity measurement: Measure the degree of leakage F within at least a portion of the test object 10 or in an enclosed space surrounding the test object 10. u The relevant physical quantity R; S4 Numerical Comparison: Compare the measured value of the physical quantity R with the first reference extreme value R. MAX and / or the second reference extreme value R MIN Compare; S5 Leakage Detection: Based on the measured physical quantity value R and the first reference extreme value R MAX The comparison results determine whether test object 10 has a leak F. u ; and / or based on the measured value of the physical quantity and the second reference extreme value R MINThe comparison results determine whether the test object has no leakage; S6 Test Interruption: If the test object is determined to have a leak or not (i.e., the object can be considered to be sealed properly), the test cycle is interrupted.
[0072] It should be noted that the physical quantity mentioned can be pressure, flow rate, or pressure that changes over time (especially pressure change per unit time).
[0073] According to an embodiment of the invention (not shown), the time-varying physical quantities are measured by an adapted leak detection device, such as device 1, which is configured to measure these physical quantities, including, for example, a pressure sensor, a flow meter, etc.
[0074] First reference extreme value R MAX With the second reference extreme value R MIN Jointly define the reference value interval I R Wherein, the measured value R of the physical quantity is compared with the reference value interval I. R Comparison: Once the measured value R exceeds the reference value range I R This allows us to determine whether the test object has a leak; if the measured value R is within the reference range I... R Boundary R MAX With R MIN During this period, the leak test continues until the end of the test cycle.
[0075] Therefore, the first reference extremum R MAX With the second reference extreme value R MIN The parameters used to define the measured value R are defined by the following formulas: First reference extreme value R MAX :R MAX =R L +M C +k1×I D ; Among them, R L M is the leakage threshold. C I is a measure of the central tendency of the compensation values. D The dispersion index is k1, which is a positive real constant. Second reference extreme value R MIN :R MIN =R L +M C -k2×I D ; Among them, R L M is the leakage threshold. C I is a measure of the central tendency of the compensation values. D is the dispersion index, and k2 is a positive real constant.
[0076] Specifically, the leakage threshold R L This is a leakage threshold level (predetermined based on the desired level of sealing), meaning that the test object 10 is considered to have a leak when this threshold is reached. In other words, if the leakage level of the test object exceeds the preset leakage threshold R... L If the leakage level of the test object is below the preset leakage threshold R, then the test object is determined to have a leak; otherwise, the leakage level of the test object is below the preset leakage threshold R. L If the test object is found to be leak-free (or, the seal is deemed to be in good condition), then the test object is determined to be leak-free (or, the seal is deemed to be in good condition).
[0077] The measured value of the physical quantity R can be defined as the degree of nonconformity or leakage rate. For example, the unit is Pa / s, but this measurement value may be offset. For example, due to the influence of environmental parameters (temperature, humidity, etc.), this offset may change within a day; or it may simply be because the (changed) pressure has not yet stabilized.
[0078] Therefore, when setting the first reference extreme value R MAX and / or the second reference extreme value R MIN At that time, this offset needs to be taken into account and compensated by the value M. C Compensation is applied to determine, as accurately as possible, whether the test object exhibits leakage, i.e., whether the leakage level exceeds a preset threshold R. L Or conversely, determine whether the test object can be considered to be sealed properly, i.e., at least the leakage level is below the preset leakage threshold R. L .
[0079] It should be noted that, in relation to the degree of leakage F u The measurement step S3 of the relevant physical quantity R can be repeated multiple times, for example, periodically, as long as the physical quantity R is at the first reference extreme value R. MAX With the second reference extreme value R MIN This applies when the measured value R is insufficient to determine whether the test object is properly sealed or if there is a leak. Therefore, each measured value R in measurement step S3 needs to be considered. i Determine the first reference extreme value R respectively MAXi With the second reference extreme value R MINi .
[0080] In this way, for example through empirical methods, it is possible to determine the optimal value for each measurement R. i Determine the first reference extreme value R MAXi With the second reference extreme value R MINi The component parameters, namely the central tendency measure M that determines the compensation value. Ci and the associated dispersion index I Di .
[0081] To complete this determination process, multiple sealing tests must be performed on objects similar to or identical to the test object (where "similar object" refers to objects that behave similarly or identically to the test object in the leakage detection method) throughout a complete test cycle to obtain the most probable value of the measurement at a specific time point, and then determine the central tendency measure M of the compensation value. C And the dispersion index I associated with the measurement step S3 at a specific time point. D .
[0082] It should be noted that the central tendency measure M C The measured value can be the arithmetic mean or the median, while the associated dispersion index I... D These correspond to the standard deviation or interquartile range, respectively.
[0083] In fact, when establishing the measured value R in measurement step S3 i When accessing the database, if the measured value R i If the statistical distribution of the compensation value is normal (i.e., the distribution is normal), then the central tendency measure M of the compensation value is... C It is the arithmetic mean, and the dispersion index I D The standard deviation is denoted as .
[0084] However, if the measured value R i If the statistical distribution of the compensation value is non-normal, then the central tendency measure M is... C It is the median, and the dispersion index I D It is the interquartile range.
[0085] Meanwhile, the constants k1 and k2 are advantageously equal to each other, and the values of the constants k1 and k2 range from 1 to 5, preferably 3.
[0086] First reference extreme value R MAX With the second reference extreme value R MIN A numerical interval can be defined as a confidence interval (i.e., the range of the confidence interval is determined by the values of constants k1 and k2), within which the probability that the measured value R is the true value meets a preset percentage. Therefore, when constants k1 and k2 are equal to 3, the probability that the measured value R is true and reliable is 99.73%; while when constants k1 and k2 are equal to 4, the probability that the measured value R is true and reliable is 99.993%.
[0087] In method 100, such as Figure 4 In the illustrated implementation variant, the method further includes step S7: placing the test object, i.e., period C i The physical quantity value R measured in the initial stage of the test is compared with the previous test object, i.e., the period C. i-1 The physical quantity value R measured at the end of the test is compared, where the period C i With period Ci-1 It consists of two consecutive cycles.
[0088] Step S7 uses a schematic diagram of two consecutive cycles in [ Figure 5 The text specifically illustrates that if the period C... i The measured physical quantity value R and period C i-1 If the measured physical quantity values R are basically equal, that is, the difference between the two values is less than 10%, preferably less than 5%, then the comparison of measurement values based on one or more extreme values is interrupted, i.e., step S1, and the long test cycle C is completed. L After a specific (or preset) time period, determine the leakage level of the test object and compare it with a preset threshold.
[0089] Therefore, the early leak detection method 100 was discontinued, and the test cycle C was completed. L To determine whether the test object has a leak, or whether the degree of leakage exceeds a preset threshold R. L It should be noted that step S7 is advantageously performed during test cycle C. L Complete it as early as possible to maximize time savings if the test subject fails.
[0090] In another embodiment of the early leak detection of the present invention, the method includes at least: Step S8 (Function Calculation Step): Calculate the function F between two different measured values of the physical quantity R; Step S9 (Function Comparison Step): Compare the calculated function F with at least one reference function F associated with function F. MIN and / or F MAX Compare them.
[0091] Implementation variants of this method 100'' are illustrated in the flowchart [ Figure 6 This is specifically shown in [ ]; therefore, except for [ Figure 5 In addition to the steps of method 100' shown, this variant also includes steps S8 and S9.
[0092] The calculated function F(R) i ,R i-1 For example, consider two measured values R of the physical quantity R. i R i-1 The difference between the two measurements, which may be continuous or discontinuous, but are distinct. Advantageously, the function F(R) i ,R i-1 The derivative of the curve of the physical quantity R or its trend over time is proportional to the measured value of the physical quantity R. For example, the function F(R) i ,R i-1 ) can be k(R) i -R i-1 The form is ), where k is the multiplication constant.
[0093] The calculation step S8 of function F can be based on the same measurement data of physical quantity R, as long as physical quantity R has been measured at least twice (i.e., step S3 has been performed once); or, additional measurements of physical quantity R can be performed, i.e., additional measurements in parallel can be used to determine whether test object 10 has a leak (according to steps S4 and S5).
[0094] The calculated function F(R) is processed through step S9. i ,R i-1 ) and the first reference extremum function F MAX and / or the second reference extremum function F MIN Compare them.
[0095] It should be noted that the first reference extremum function is calculated using the following formula: F MAX =F m +k3×I F ; Among them, F m To calculate the measure of central tendency of the function, I F k3 is a positive real constant and represents the dispersion index relative to the computation function.
[0096] Meanwhile, the second reference extremum function is calculated by the following formula: F MIN =F m -k4×I F ; Among them, F m To calculate the measure of central tendency of the function, I F k4 is a positive real constant and is a measure of the dispersion relative to the computational function.
[0097] As mentioned above, the central tendency measure F of the calculation function is... m It can be the arithmetic mean or the median, and the dispersion index I of the calculation function. F These correspond to the standard deviation or interquartile range, respectively. The central tendency measure F of the calculation function is then used. m and dispersion index I F The choice of type depends on the distribution type of the calculation function (normal or non-normal).
[0098] Furthermore, the constants k3 and k4 are advantageously equal, and their values are, for example, at least 2; and preferably at least 3, depending on the expected accuracy requirements.
[0099] According to the calculation function F(R) i ,R i-1 ) and the first reference extremum function F MAX and / or the second reference extremum function F MINBased on the comparison results, either continue with the early leak detection method 100'', or complete the test cycle C. L And, for example, issue indicative alarms to operators.
[0100] Specifically, if the function F(R) is calculated i ,R i-1 ) is in the reference range [F MIN ;F MAX If the value is within the range of ], it is considered that there is no abnormal situation that would cause the leak test to fail, and the leak detection method continues to be executed; however, if the calculation function F(R) is within the range of ], it is considered that there is no abnormal situation that would cause the leak test to fail, and the leak detection method continues to be executed; i ,R i-1 ) Exceeds the reference range [F MIN ;F MAX If the result is positive, it indicates that an abnormal situation has occurred during the leak test, and a long test cycle C needs to be performed on the test object. L To ensure the accuracy of leak testing.
[0101] It should be noted that steps S3 to S5, S7 and / or S8 and S9 can be implemented simultaneously or sequentially, depending on the environmental conditions of the leak test and / or the environmental conditions of the test object.
[0102] The present invention also relates to a filtering method 200 for a leakage test cycle for a test object type, which, by constructing a database, can determine at least one reference value related to leakage testing of the object type.
[0103] Specifically, the filtering method 200 can construct a database BDD to determine (or calculate) various reference extreme values R for different types of measurement data for the physical quantity R. MAX R MIN and / or reference extreme value function F MAX F MIN This provides support for the optimized implementation of the aforementioned early leak detection methods 100, 100', and 100''.
[0104] The method 200 includes at least the following steps: Select / Study E1: For test cycle C L Make a selection / research; Determine E2: Calculate the total difference Δ T The total difference Δ T For test cycle C L The measured value of the physical quantity R at the initial moment. ini The measured value of the physical quantity R at the end of the period fin The difference between them; Compare E3: Calculate the total difference Δ T Total difference Δ from reference TrefComparison, and preference is given to the first reference extreme value Δ. Tref1 Second reference extreme value Δ Tref2 Compare; Judgment Step: Determine the test period C L Whether it can be included in the database for determining at least one reference value.
[0105] It should be noted that the test cycle C L The start and end times refer to the representative values of the physical quantity R at the beginning and end of the test; these representative values can be measurements at a specific point in time (e.g., after its stability and representativeness have been determined through experience), or they can be the average of the first and last measurements.
[0106] Specifically, based on the test period C in the database BDD L The following parameters were calculated: Reference total difference Δ Tref This parameter is a measure of central tendency; Dispersion index I Δ This indicator is for the reference total difference Δ Tref The calculated dispersion parameter.
[0107] The central tendency measure Δ Tref It can be the arithmetic mean or the median, and the corresponding dispersion index I Δ These are the standard deviation or interquartile range, respectively (depending on the distribution type of the total difference).
[0108] Therefore, the comparison is advantageously used to verify: the total difference Δ over the test period T The central tendency measure ΔTref and the dispersion index I are calculated. Δ Within the commonly defined interval, i.e., Δ Tref1 =Δ Tref -k e ×I Δ ≤Δ T ≤Δ Tref +k e ×I Δ =Δ Tref2 , where k e The constant k is a positive real constant. e The value of is between 1 and 5, with 1 being the preferred value.
[0109] Therefore, if the total difference Δ over the testing period T If the test period C falls within the aforementioned defined range, then the test period C is... L(i.e., the set of all measurement points) will be incorporated into the database BDD to evaluate some reference values of the database and / or provide data support for early leak detection decision-making methods 100, 100', or 100'' for specific objects or object types.
[0110] Otherwise, test cycle C L The measured values of the physical quantity R and its related quantities will not be included in the construction process of the database BDD, and will be tested in another test cycle through filtering method 200, for example, selecting a recorded test cycle.
[0111] [ Figure 8 [This shows] Figure 7 The first implementation variant of the filtering method shown; Figure 8 The filtering method 200' shown in [ Figure 7 Based on method 200 shown, the following steps are further included: Determine E4: During test cycle C L Within, calculate at least two consecutive and distinct sets of measurements R for the physical quantity R. i With R i-1 The difference Δ between i1 and Δ i2 (This is called the intermediate difference); Compare E5: The at least two sets of intermediate differences Δ i1 and Δ i2 Each intermediate difference Δ i1 Δ i2 At least one corresponding reference value Δ ref1 and Δ ref2 Compare them.
[0112] It should be noted that steps E4 and E5 can be repeatedly performed on the measured value of the physical quantity R in a sliding manner to verify the test cycle C. L There are no interfering factors that would prevent it from being included in the database BDD.
[0113] Specifically, based on the test period C in the database BDD L The following parameters were calculated: Intermediate differences Δ i1 Δ i2 The corresponding reference value Δ ref1 Δ ref2 The reference values are each a measure of central tendency; Dispersion index I i1 I i2 The indicators mentioned are for each intermediate difference Δ i1 Δ i2 The corresponding reference value Δ ref1 Δref2 The calculated dispersion parameter.
[0114] Intermediate differences Δ i1 or Δ i2 Corresponding measure of central tendency (reference value Δ) ref1 or Δ ref2 The value can be the arithmetic mean or the median, and the corresponding dispersion index I... i1 and I i2 These are the standard deviation or interquartile range, respectively.
[0115] Specifically, the comparison E5 is advantageously used to verify: test cycle C L The median difference Δ i1 and Δ i2 They are respectively located in the corresponding central tendency measures (Δ) obtained by calculation. ref1 Δ ref2 ), and the dispersion index of the association (I) i1 I i2 ) and positive real constants (k) i1 k i2 Within the interval jointly defined by Δ ref1 -k i1 ×I i1 ≤Δ i1 ≤Δ ref1 +I i1 , and Δ ref2 -k i2 ×I i2 ≤Δ i2 ≤Δ ref2 +I i2 ; Where, k i1 k i2 All are positive real constants.
[0116] Therefore, if each intermediate difference Δ i1 Δ i2 If the test period C falls within the aforementioned defined range, then the test period C is... L (i.e., the set of all measurement points) will be incorporated into the database BDD to evaluate some reference values of the database, optimize the filtering methods (200, 200'), and / or provide data support for early leak detection decision methods 100, 100' or 100'' for specific objects or object types.
[0117] Meanwhile, the constant k i1 With k i2 They are advantageously equal, with values ranging from 1 to 5, preferably equal to 1.
[0118] The filtering method 200' may also include the following additional steps: Compare E6: Change the test cycle C i The measured value of the physical quantity R at the initial moment. ini Compared with the previous test cycle C i-1 The measured value of the physical quantity R at the end of the period fin The comparison is made, wherein the test period C is... i With C i-1 For continuous testing cycles; Decision E7: Determine the test cycle C i Whether it can be included in the database BDD for determining at least one reference value.
[0119] If the measured values are substantially equal, then the test period C i The database BDD will not be included.
[0120] Specifically, it can also be based on a central tendency measure M C And a dispersion index I associated with each of the aforementioned measures of central tendency. D Execute the continuous test cycle C i With C i-1 Step E6: Comparison of measured values of physical quantity R between the two quantities.
[0121] A measure of central tendency M used for comparing measurements over two consecutive test weeks. C , which can be the arithmetic mean or the median; and the associated dispersion index I D Then it can be the standard deviation or the interquartile range.
[0122] Specifically, each measured value R can be analyzed in the following ways. ini and R fin Limit the range: M C -k×I D ≤R ini ≤M C +k×I D ; M C -k×I D ≤R fin ≤M C +k×I D ; Where k is a positive real constant (e.g., between 1 and 5, preferably equal to 1); M C and I D The parameters are still calculated based on the test cycles recorded in the database BDD, and are defined as described above.
[0123] By comparing the measured value R ini With R finThe interval is defined to determine whether there is any overlap between the two; if there is overlap, the test period C is determined. i The database BDD will not be included; if there is no overlap, then the test period C... i They will be incorporated into the database BDD to evaluate some reference values of the database BDD, optimize the filtering methods (200, 200'), and / or provide data support for early leakage detection decision methods 100, 100', or 100'' for specific objects or object types.
[0124] Steps E2 and E3, E4 and E5, and E6 can be executed sequentially or simultaneously; however, the test cycle C for analysis / testing using the filtering method (200, 200') of this invention is... L In order to be included in the database BDD, the comparison criteria of steps E3, E5 and / or E7 must be met.
[0125] It should be noted that the present invention also relates to an electronic device, such as a leak detection device 1 or a computer, which is configured to perform the filtering methods 200, 200' of the leak test cycle as described above.
Claims
1. An early leakage detection method (10; 100';) for a test object (10) based on a leakage detection device (1); 100''), the method (100; 100'; (100'') includes the following steps: - Application step (S2): Apply a pressure difference within at least a portion of the test object (10) or in a cavity surrounding the test object, the pressure difference being relative to the outside of the test object (10) or relative to at least a portion of the test object (10); - Measurement Step (S3): During a test cycle of a preset duration (C) L Within the test object (10), the degree of leakage (F) is measured in at least a portion of the test object or in the cavity surrounding the test object. u The related physical quantity (R); - Comparison step (S4): Compare the measured value of the physical quantity (R) with the first reference extreme value (R). MAX R MIN ) for comparison; - Determination step (S5): Based on the measured value and the first reference extreme value (R) MAX R MIN The comparison results are used to determine whether the test object (10) has a leak; - Interruption step (S6): If it is determined that the test object (10) has a leak, then the test cycle (C) is interrupted. L ).
2. The method (100; 100'; 100'') according to claim 1, characterized in that, The method (100; 100'; 100'') further includes the following steps: - Comparison step (S4): Compare the measured value of the physical quantity (R) with the second reference extreme value (R). MAX R MIN ) for comparison; - Determination step (S5): Based on the measured value of the physical quantity (R) and the second reference extreme value (R... MAX R MIN The comparison results are used to determine whether the test object (10) has no leakage; - Interruption step (S6): If it is determined that the test object (10) does not have a leak, then the test cycle (C) is interrupted. L ).
3. The method (100; 100'; 100'') according to claim 1 or 2, characterized in that, First reference extreme value and second reference extreme value (R MAX R MIN Together they define a reference value range (I) R ); wherein, by comparing the measured value of the physical quantity (R) with the reference value range (I) R The measurement (R) is compared with the reference value range (I) once the measured value (R) exceeds the reference value range (I). R ), and it can be determined whether the test object (10) has a leak; and as long as the measured value (R) is within the reference value range (I R Leakage testing continues between the boundaries of the test cycle (C) until the specified test period (C). L )Finish.
4. The method (100; 100'; 100'') according to any one of the preceding claims, characterized in that, The first reference extreme value (R) MAX R is defined by the following formula: MAX =R L +M C +k1×I D ; Among them, R L M is the leakage threshold. C I is a measure of the central tendency of the compensation values. D is the dispersion index, and k1 is a positive real constant.
5. The method (100; 100'; 100'') according to claim 2 or 3, characterized in that, The second reference extreme value (R) MIN R is defined by the following formula: MIN =R L +M C -k2×I D ; Among them, R L M is the leakage threshold. C I is a measure of the central tendency of the compensation values. D is the dispersion index, and k2 is a positive real constant.
6. The method (100; 100'; 100'') according to claims 4 and / or 5, characterized in that, The measure of central tendency (M) C ) and dispersion index (I D The value of ) is determined based on multiple tests performed on multiple objects of the same type as the test object (10).
7. The method according to claim 6 (100; 100'; 100''), characterized in that, The measure of central tendency (M) C The arithmetic mean or median is used, while the dispersion index (I) is used for other purposes. D These correspond to the standard deviation or interquartile range, respectively.
8. The method (100'; 100'') according to any one of the preceding claims, characterized in that, If the test period (C) i The physical quantity at the initial moment (R) ini ) Measurement value and the previous test cycle (C i-1 The last measurement (R) fin If the values are substantially equal, then the measurement comparison step based on one or more reference extreme values is interrupted, and the test cycle (C) is continued. L Once the degree of leakage is determined, it is compared with a preset threshold (R). L (Compare) 9. The method (100'') according to any one of the preceding claims, characterized in that, The method (100'') further includes the following steps: - Calculation steps: Based on two different measurements of a physical quantity (R i R i-1 ) Calculate function (F); - Comparison step: Compare the calculated function F(R) i , R i-1 ) and the first reference extremum function (F MAX F MIN ) for comparison; - Based on the calculation function F(R) i , R i-1 ) and the first reference extremum function (F MAX F MIN The comparison results indicate that either the early leak detection method (100'') will continue, or the test cycle (C) will be completed. L ).
10. The method (100; 100'; 100'') according to the preceding claims, characterized in that, It also includes the calculated function F(R) i , R i-1 ) and (F MAX F MIN The steps of comparison; based on the calculated function F(R) i , R i-1 ) and the second reference extremum function (F MAX F MIN The comparison results indicate that either the early leak detection method (100; 100'; 100'') will continue, or the test cycle (C) will be completed. L ).
11. The method (100'') according to claim 10, characterized in that: - The first reference extremum function is calculated using the following formula: F MAX =F m +k3×I F ; Among them, F m To calculate the measure of central tendency of the function, I F k3 is a positive real constant and represents the dispersion index relative to the computation function.
12. The method (100'') according to the preceding claim, characterized in that: - The second reference extremum function is calculated using the following formula: F MIN =F m -k4×I F ; Among them, F m To calculate the measure of central tendency of the function, I F k is the dispersion index of the calculation function, and k4 is a positive real constant.
13. The method (100'') according to any one of claims 10 to 12, characterized in that, The calculation function F(R) i , R i-1 ) is the difference and / or ratio between two measured values of a physical quantity (R).
14. A differential pressure leak detection device (1) configured to perform an early leak detection method (100; 100'; 100'') according to any one of the preceding claims.