A method, device and system for detecting the tightness of a plastic bottle

Abstract

The present application relates to the technical field of mechanism sealing test, in particular to a plastic bottle sealing performance detection method, device and system, the method comprises: obtaining the delay degree of the actual pressure of the plastic bottle reaching the target pressure in the plastic bottle pressurization process, combining the plastic bottle pressure fluctuation in the pressurization process, the delay degree and the plastic bottle pressure fluctuation reflect the sealing performance of the plastic bottle in the pressurization process, so as to obtain the plastic bottle pressure abnormality degree in the pressurization process; determine the plastic bottle pressure drop feature in the plastic bottle pressure maintaining process, the plastic bottle pressure drop feature reflects the sealing performance of the plastic bottle in the pressure maintaining process, finally, the plastic bottle pressure abnormality degree and the plastic bottle pressure drop feature are comprehensively determined, the characteristics of the pressurization process and the pressure maintaining process are comprehensively determined, the plastic bottle sealing performance index is obtained, the accuracy and reliability of the plastic bottle sealing performance detection result can be significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanism sealing testing, and in particular to a method, device and system for detecting the sealing of a plastic bottle. Background Art

[0002] The sealing performance of plastic bottles, a core performance indicator, is directly related to product quality and safety. Existing methods typically use air pressure testing to determine the sealing performance of plastic bottles. This method uses the difference between the pressure measured during the test and the target pressure to determine the sealing performance. However, this single-indicator-based method can lead to inaccurate and unreliable results. Summary of the Invention

[0003] In order to solve the technical problem of poor reliability of existing plastic bottle sealing detection methods, the present invention aims to provide a plastic bottle sealing detection method, device and system. The technical solutions adopted are as follows:

[0004] In a first aspect of the present invention, a method for detecting the sealing property of a plastic bottle is provided, comprising:

[0005] Obtain the delay between the actual pressure of the plastic bottle reaching the target pressure during the pressurization process of the plastic bottle;

[0006] Determine the pressure fluctuation of the plastic bottle during the pressurization process, and obtain the abnormality of the pressure of the plastic bottle during the pressurization process in combination with the delay degree;

[0007] determining a pressure drop characteristic of the plastic bottle during the pressure-maintaining process, wherein the pressure drop characteristic of the plastic bottle represents a decrease in the pressure of the plastic bottle during the pressure-maintaining process;

[0008] A sealing performance index of the plastic bottle is obtained according to the abnormal degree of the plastic bottle pressure and the pressure drop characteristics of the plastic bottle.

[0009] In an exemplary embodiment, the plastic bottle sealing detection method further includes:

[0010] Obtaining a total pressure change curve of a plurality of plastic bottles, wherein the total pressure change curve is composed of the pressure change curves of the plastic bottles during the pressurization process and the pressure holding process;

[0011] Determine the similarity between the total pressure change curve of a target plastic bottle and the total pressure change curves of each reference plastic bottle, and obtain a similarity mean corresponding to the target plastic bottle; the target plastic bottle is a plastic bottle to be tested; the reference plastic bottles are each plastic bottle other than the target plastic bottle; the plurality of plastic bottles includes the target plastic bottle and the reference plastic bottles;

[0012] The plastic bottle sealing performance index and the similarity mean of the target plastic bottle are fused to obtain a final plastic bottle sealing performance index of the target plastic bottle.

[0013] In an exemplary embodiment, after obtaining the similarity mean, the plastic bottle sealing detection method further includes:

[0014] Determine a reference duration difference and a total duration difference of the target plastic bottle, wherein the reference duration difference is the difference between the reference duration of the target plastic bottle and the standard reference duration, and the total duration difference is the difference between the total duration of the target plastic bottle and the standard total duration; the reference duration is the pressurization duration when a reference pressure appears, and the reference pressure is the pressure value closest to the target pressure that appears for the first time during the pressurization process; and the total duration is the duration of the total pressure change curve;

[0015] Based on the reference duration difference and the total duration difference of the target plastic bottle, a correction coefficient of the target plastic bottle is obtained, and the correction coefficient is used to correct the similarity mean corresponding to the target plastic bottle.

[0016] In an exemplary embodiment, the process of obtaining the standard reference duration and the standard total duration includes:

[0017] Obtaining a key feature vector of each reference plastic bottle, wherein the key feature vector is composed of a reference duration and a total duration of the reference plastic bottle;

[0018] Cluster the reference plastic bottles according to the key feature vectors of each reference plastic bottle to obtain the cluster with the largest number of reference plastic bottles;

[0019] The average value of the reference durations of the reference plastic bottles in the cluster is used as the standard reference duration, and the average value of the total durations of the reference plastic bottles in the cluster is used as the standard total duration;

[0020] The correction coefficient of the target plastic bottle is obtained based on the reference time difference and the total time difference of the target plastic bottle, including:

[0021] A correction coefficient of the target plastic bottle is obtained based on the reference time difference and the total time difference of the target plastic bottle, as well as the proportion of the number of reference plastic bottles in the cluster; the correction coefficient is proportional to the proportion of the number of reference plastic bottles, and inversely proportional to the reference time difference and the total time difference.

[0022] In an exemplary embodiment, the process of obtaining the delay degree includes:

[0023] Obtaining a reference pressure and a reference duration of the plastic bottle during the pressurization process, wherein the reference pressure is a pressure value closest to the target pressure that appears for the first time during the pressurization process, and the reference duration is the pressurization duration when the reference pressure appears;

[0024] The degree of delay is obtained based on the pressure difference and the duration difference; the degree of delay is proportional to both the pressure difference and the duration difference, the pressure difference being the difference between the target pressure and the reference pressure, and the duration difference being the difference between the reference duration and the theoretical duration.

[0025] In an exemplary embodiment, the process of obtaining the pressure fluctuation of the plastic bottle includes:

[0026] Determine the average value of each fluctuation amplitude in the pressure change curve of the plastic bottle during the pressurization process to obtain a fluctuation amplitude feature, wherein the fluctuation amplitude is the pressure difference between adjacent peaks and troughs;

[0027] Determine the average value of the difference between any two fluctuation durations in the pressure change curve of the plastic bottle during the pressurization process to obtain a fluctuation duration difference feature, where the fluctuation duration is the time interval between adjacent peaks and troughs;

[0028] The maximum value of all the fluctuation durations is determined to obtain the maximum fluctuation duration.

[0029] In an exemplary embodiment, the process of obtaining the abnormal pressure level of the plastic bottle includes:

[0030] The abnormal degree of the plastic bottle pressure is obtained according to the delay degree, fluctuation amplitude characteristics, fluctuation duration difference characteristics and maximum fluctuation duration; the abnormal degree of the plastic bottle pressure is proportional to the delay degree and fluctuation amplitude characteristics, and inversely proportional to the fluctuation duration difference characteristics and maximum fluctuation duration.

[0031] In an exemplary embodiment, the pressure drop characteristic of the plastic bottle includes a pressure drop speed characteristic, and a process of acquiring the pressure drop speed characteristic includes:

[0032] Determine the decreasing rate of each pressure value in the pressure change curve of the plastic bottle during the pressure holding process, and determine the average decreasing rate, the maximum decreasing rate, and the time when the maximum decreasing rate occurs;

[0033] The pressure drop rate characteristic is obtained according to the average drop rate, the maximum drop rate and the occurrence time of the maximum drop rate. The pressure drop rate characteristic is proportional to the average drop rate and the maximum drop rate, and inversely proportional to the occurrence time.

[0034] In a second aspect of the present invention, a plastic bottle sealing detection device is provided, comprising a computer-readable storage medium storing a computer program, which implements the steps of the above-mentioned plastic bottle sealing detection method when executed by a processor.

[0035] In a third aspect of the present invention, a plastic bottle sealing detection system is provided, comprising: a memory and a processor; the memory is connected to the processor; the memory is used to store program instructions; and the processor is used to implement the above-mentioned plastic bottle sealing detection method when the program instructions are executed.

[0036] The present invention has the following beneficial effects: the present invention sequentially performs a pressurizing process and a pressure-holding process on a plastic bottle, and during the pressurizing process, obtains the degree of delay for the actual pressure of the plastic bottle to reach the target pressure and the pressure fluctuation of the plastic bottle, the degree of delay and the pressure fluctuation of the plastic bottle reflect the sealing performance of the plastic bottle during the pressurizing process, thereby obtaining the degree of abnormal pressure of the plastic bottle during the pressurizing process, and then during the pressure-holding process, determines the pressure drop characteristics of the plastic bottle during the pressure-holding process, the pressure drop characteristics of the plastic bottle reflect the sealing performance of the plastic bottle during the pressure-holding process, and then comprehensively obtains the characteristics of the pressurizing process and the pressure-holding process to obtain the plastic bottle sealing performance index, which can significantly improve the accuracy and reliability of the plastic bottle sealing test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a flowchart of the steps of a method for detecting the sealing property of a plastic bottle provided by one embodiment of the present invention;

[0038] Figure 2 is a flowchart of obtaining the delay degree provided by one embodiment of the present invention;

[0039] Figure 3 is a flow chart for obtaining a pressure drop rate characteristic provided by one embodiment of the present invention;

[0040] Figure 4 A flowchart of the steps included in a method for detecting the sealing performance of a plastic bottle provided by one embodiment of the present invention;

[0041] Figure 5 is a flowchart of similarity mean correction provided by one embodiment of the present invention;

[0042] Figure 6 This is a flowchart for obtaining the standard reference duration and the standard total duration provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] To further illustrate the technical means and effects employed by the present invention to achieve its intended objectives, the following detailed description of the specific embodiments, structures, features, and effects of the present invention is provided in conjunction with the accompanying drawings and preferred embodiments. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this invention pertains. The data and information collected in this application were obtained with full consent and authorization.

[0045] The present embodiment provides a method for detecting the sealing properties of plastic bottles to perform sealing tests on plastic bottles. The method for detecting the sealing properties of plastic bottles provided in the present embodiment is suitable for performing sealing tests on plastic bottles using an air pressure method. During the preliminary preparation process, it is first necessary to clean the bottle body and the bottle cap to remove oil and dust, and ensure that there is no liquid residue or impurities in the bottle to avoid affecting the sealing effect; use a sealing adapter that matches the bottle mouth (such as a threaded or compression type) to ensure that the bottle mouth is tightly connected to the inflation device to avoid external leakage; then, confirm that the air pressure detection device such as the pressure controller, pressure sensor, inflation valve, and deflation valve are functioning properly, and calibrate the pressure sensor to monitor the dynamic changes in pressure in the plastic bottle in real time through the pressure sensor.

[0046] Parameter setting: Determine the target pressure, inflation rate, and pressure holding time based on the volume of the plastic bottle to be tested. For example, for small bottles below 500 ml, the target pressure is usually set to 0.4-0.6 MPa. In this embodiment, it is set to 0.5 MPa. When the volume of the plastic bottle is small, a too fast inflation rate can easily lead to pressure overshoot or even bottle rupture. Therefore, the inflation rate is set to 0.03 MPa / s and the pressure holding time is 60 seconds; the pressure relief rate is set to 0.1 MPa / s to avoid rapid pressure relief causing residual air pressure in the bottle to affect the judgment.

[0047] The air pressure testing process primarily consists of a pressurization phase and a pressure-maintaining phase. The pressurization phase involves first opening the inflation valve and filling the plastic bottle to the target pressure at a set inflation rate. During inflation, pressure changes are recorded at a preset sampling frequency. This sampling frequency depends on the bottle's volume and inflation rate. Small bottles (e.g., under 500 mL) experience a short inflation time (typically within a few seconds) and a rapid pressure rise, requiring a higher sampling frequency (e.g., 0.1-0.5 seconds / sample) to capture peak pressure fluctuations during the rapid inflation phase. Large bottles (e.g., over 1 L) experience a longer inflation time and relatively gradual pressure changes, requiring a lower sampling frequency (e.g., 0.5-1 second / sample). During the pressurization process, the real-time pressure data is used to generate a pressure sequence for the bottle, which is then plotted as a pressure curve.

[0048] After the internal pressure of the plastic bottle reaches the target pressure, the inflation valve is closed, and the pressure holding process begins. The pressure data of the plastic bottle during the pressure holding time is recorded. To capture micro-leakage signals, the sampling frequency can be 2 times / second. During the pressure holding process, the real-time pressure data is obtained to obtain the pressure sequence of the plastic bottle during the pressure holding process, and then a pressure change curve of the plastic bottle during the pressure holding process is plotted.

[0049] In addition, after the pressure holding process is completed, the pressure relief valve is slowly opened to release the pressure on the plastic bottle at a set rate until the pressure drops to the ambient pressure. At the same time, the pressure changes during the pressure relief process can also be recorded.

[0050] When the sealing performance of a plastic bottle is normal, the pressure inside the bottle exhibits distinct characteristics at different stages. First, during the inflation phase (i.e., the pressurization process), the pressure inside the bottle rises linearly or approximately linearly over time, with a steady increase in pressure and no significant fluctuations or stagnation. During the pressure-holding process, there is no gas leakage, and the pressure inside the bottle remains stable or decreases very slowly. During the pressure relief process, the pressure drops rapidly to ambient pressure. In actual testing, the plastic bottle under test may have sealing issues, resulting in the recorded pressure changes differing from the theoretical values. Therefore, this embodiment determines the sealing performance of the plastic bottle based on the pressure changes during the pressurization and pressure-holding processes.

[0051] like Figure 1 As shown, this embodiment provides a method for detecting the sealing property of a plastic bottle, comprising the following steps:

[0052] Step 1: Obtain the delay between the actual pressure of the plastic bottle and the target pressure during the pressurization process of the plastic bottle;

[0053] Step 2: Determine the pressure fluctuation of the plastic bottle during the pressurization process, and combine it with the delay degree to obtain the abnormal degree of the pressure of the plastic bottle during the pressurization process;

[0054] Step 3: Determine the pressure drop characteristics of the plastic bottle during the pressure holding process;

[0055] Step 4: Obtain the sealing performance index of the plastic bottle according to the abnormal degree of the plastic bottle pressure and the pressure drop characteristics of the plastic bottle.

[0056] The specific implementation process of each step is described below in conjunction with the accompanying drawings.

[0057] Step 1: Obtain the delay between the actual pressure of the plastic bottle and the target pressure during the pressurization process of the plastic bottle.

[0058] When there is a sealing problem with the plastic bottle, air leakage will occur during the pressurization process. The air leakage and inflation will form a dynamic equilibrium process, resulting in a longer time to reach the target pressure. This dynamic process of air leakage and inflation will be reflected on the pressure change curve as a small sawtooth fluctuation in the curve. Moreover, when there is a big problem with the sealing of the plastic bottle, that is, when the air leakage is serious, the internal pressure of the plastic bottle may not reach the target pressure, or it may drop rapidly after reaching the target pressure. Therefore, during the pressurization process of the plastic bottle, if there is no sealing problem with the plastic bottle, the actual pressure of the plastic bottle will reach the target pressure at a predetermined speed. However, if there is a sealing problem with the plastic bottle, there will be a certain time delay for the actual pressure of the plastic bottle to reach the target pressure, and the worse the sealing is, the higher the degree of delay. Therefore, the degree of delay in the actual pressure of the plastic bottle reaching the target pressure during the pressurization process of the plastic bottle is obtained, and the degree of delay can characterize the sealing of the plastic bottle during the pressurization process. In an exemplary embodiment, as Figure 2 As shown, a specific process of obtaining the delay degree is given as follows:

[0059] Step 1-1: Obtain a reference pressure and a reference duration of the plastic bottle during a pressurization process.

[0060] During the pressurization process, the pressure inside the plastic bottle gradually rises. If the bottle is leak-proof, the actual pressure will reach the target pressure. If the leak is not severe (i.e., the leak is not serious), the pressure inside the bottle will reach the target pressure, but the time to reach the target pressure will be delayed. If the leak is severe (i.e., the leak is serious), the pressure inside the bottle may not reach the target pressure, or may drop rapidly after reaching the target pressure. Furthermore, during the period close to the target pressure, the dynamic process of leaking and filling will cause pressure fluctuations.

[0061] Therefore, the pressure sequence of the plastic bottle during the pressurization process is obtained, and then the difference between the target pressure and each pressure value in the pressure sequence of the plastic bottle during the pressurization process is calculated, so as to obtain a difference sequence by time sequence. The smaller the difference in the difference sequence, the smaller the gap from the target pressure. If the difference sequence is a monotonically decreasing sequence, the minimum value in the difference sequence is obtained. It can be understood that the plastic bottle pressure corresponding to the minimum value is the pressure value closest to the target pressure that appears for the first time, and this pressure value is recorded as the reference pressure. When the plastic bottle does not have a sealing problem, or the sealing problem of the plastic bottle is not very serious, the reference pressure is equal to the target pressure; when the sealing problem of the plastic bottle is very serious and the plastic bottle cannot reach the target pressure, the reference pressure is less than the target pressure. Therefore, the reference pressure is less than or equal to the target pressure.

[0062] If the difference sequence is not a monotonically decreasing sequence, and it increases after reaching a minimum value, then the first minimum value in the time series of the difference sequence is obtained. This minimum value indicates that the difference between the plastic bottle pressure and the target pressure is the smallest. It can be understood that the plastic bottle pressure corresponding to this minimum value is the first pressure value closest to the target pressure, and this pressure value is recorded as the reference pressure. Therefore, if the difference sequence is not a monotonically decreasing sequence, it means that the sealing problem of the plastic bottle is very serious, and the pressure of the plastic bottle quickly drops after reaching or approaching the target pressure. Therefore, the reference pressure is less than or equal to the target pressure. In summary, the obtained reference pressure is less than or equal to the target pressure.

[0063] The time when the reference pressure appears is obtained, and the time interval between the time when the reference pressure appears and the time when the pressurization starts is obtained as the pressurization duration corresponding to the reference pressure, and the pressurization duration is defined as the reference duration.

[0064] Step 1-2: Obtain the degree of delay based on the pressure difference and duration difference.

[0065] Obtain the difference between the target pressure and the reference pressure, that is, calculate the difference between the target pressure and the reference pressure, and define it as the pressure difference. Since the reference pressure is less than or equal to the target pressure, the pressure difference is greater than or equal to 0. A larger pressure difference indicates a greater delay in the pressure inside the plastic bottle reaching the target pressure, a more severe delay in the actual pressure of the plastic bottle reaching the target pressure, and a more serious sealing problem in the plastic bottle.

[0066] Since the target pressure and the inflation rate during the pressurization process are predetermined before the pressurization test, the ratio of the target pressure to the inflation rate can be calculated to obtain the theoretical time required for the pressure inside the plastic bottle to reach the target pressure, defined as the theoretical duration. It should be understood that if the plastic bottle does not have a sealing issue, the pressure in the plastic bottle will normally increase to the target duration, and the reference duration of the plastic bottle will equal the theoretical duration. If the plastic bottle does have a sealing issue, the pressure inside the plastic bottle will increase more slowly than normal, and the pressure in the plastic bottle will reach the reference pressure more slowly, resulting in the reference duration being greater than the theoretical duration. Therefore, the reference duration is greater than or equal to the theoretical duration. The difference between the reference duration and the theoretical duration is calculated, defined as the duration difference, and this duration difference is greater than or equal to 0. The greater the duration difference, the greater the delay in the pressure inside the plastic bottle reaching the target pressure, and the more severe the delay in the actual pressure of the plastic bottle reaching the target pressure.

[0067] Therefore, the degree of delay is obtained based on the pressure difference and the time difference, and the degree of delay is proportional to both the pressure difference and the time difference. In an exemplary embodiment, a specific quantitative method of the degree of delay is given as follows:

[0068] ;

[0069] in, For the degree of delay, is the pressure difference, The difference in duration. represents a normalization function. In this embodiment, the normalization involved can adopt the following method: hyperbolic tangent function (tanh).

[0070] By taking the average value of the two normalized differences to fuse the pressure difference and the duration difference, the impact of the two differences on the delay degree can be comprehensively considered to obtain the delay degree.

[0071] Step 2: Determine the pressure fluctuation of the plastic bottle during the pressurization process, and combine it with the delay degree to obtain the abnormal degree of the plastic bottle pressure during the pressurization process.

[0072] During the pressurization process, if the plastic bottle has no sealing issues, the pressure of the plastic bottle will change relatively smoothly during the pressurization process. However, if the plastic bottle has a sealing issue, the pressure of the plastic bottle will fluctuate during the pressurization process. The more serious the sealing issue, the more significant the pressure fluctuation during the pressurization process. Therefore, the pressure fluctuation of the plastic bottle is obtained. In an exemplary embodiment, the pressure fluctuation of the plastic bottle includes three parts: fluctuation amplitude characteristics, fluctuation duration difference characteristics, and maximum fluctuation duration.

[0073] The acquisition process of the fluctuation amplitude feature includes: determining each peak and trough in the plastic bottle pressure change curve of the pressurization process, acquiring the pressure difference between adjacent peaks and troughs, i.e., the difference between the pressure value corresponding to the peak and the pressure value corresponding to the trough, as a fluctuation amplitude, traversing all peaks and troughs in the plastic bottle pressure change curve of the pressurization process to obtain multiple fluctuation amplitudes. Then, the average of the obtained multiple fluctuation amplitudes is calculated as the fluctuation amplitude feature of the pressurization process. The fluctuation amplitude feature is used to represent the plastic bottle pressure change amplitude of the pressurization process. The smaller the plastic bottle pressure change amplitude, the closer the air leakage amount and the air charging amount to the balance, the more gentle the fluctuation, and the more slight the air leakage degree. The larger the plastic bottle pressure change amplitude, the more intense the pressure fluctuation, and the more serious the air leakage degree. It should be understood that when there are almost no peaks or troughs in the plastic bottle pressure change curve of the pressurization process, i.e., the pressure change is very smooth, the obtained fluctuation amplitude is very small, and the fluctuation amplitude feature is very small. Therefore, the fluctuation amplitude feature can represent the severity of the sealing problem of the plastic bottle. In addition, in special cases, if the plastic bottle pressure change curve of the pressurization process is an absolutely monotonically increasing curve, there are no peaks and troughs, and the fluctuation amplitude feature is 0.

[0074] The acquisition process of the fluctuation amplitude feature includes: determining each peak and trough in the plastic bottle pressure change curve of the pressurization process, acquiring the pressure difference between adjacent peaks and troughs, i.e., the difference between the pressure value corresponding to the peak and the pressure value corresponding to the trough, as a fluctuation amplitude, traversing all peaks and troughs in the plastic bottle pressure change curve of the pressurization process to obtain multiple fluctuation amplitudes. Then, the average of the obtained multiple fluctuation amplitudes is calculated as the fluctuation amplitude feature of the pressurization process. The fluctuation amplitude feature is used to represent the plastic bottle pressure change amplitude of the pressurization process. The smaller the plastic bottle pressure change amplitude, the closer the air leakage amount and the air charging amount to the balance, the more gentle the fluctuation, and the more slight the air leakage degree. The larger the plastic bottle pressure change amplitude, the more intense the pressure fluctuation, and the more serious the air leakage degree. It should be understood that when there are almost no peaks or troughs in the plastic bottle pressure change curve of the pressurization process, i.e., the pressure change is very smooth, the obtained fluctuation amplitude is very small, and the fluctuation amplitude feature is very small. Therefore, the fluctuation amplitude feature can represent the severity of the sealing problem of the plastic bottle. In addition, in special cases, if the plastic bottle pressure change curve of the pressurization process is an absolutely monotonically increasing curve, there are no peaks and troughs, and the fluctuation amplitude feature is 0.

[0075] Then, according to the pressure fluctuation and delay degree of the plastic bottle during the pressurization process, the abnormality degree of the plastic bottle pressure during the pressurization process is obtained. Specifically: according to the respectively obtained delay degree, fluctuation amplitude characteristic, fluctuation duration difference characteristic and maximum fluctuation duration, the abnormality degree of the plastic bottle pressure is obtained. Among them, the higher the delay degree, the higher the abnormality degree of the plastic bottle pressure; the higher the fluctuation amplitude characteristic, the higher the abnormality degree of the plastic bottle pressure; the smaller the fluctuation duration difference characteristic, the higher the abnormality degree of the plastic bottle pressure; the smaller the maximum fluctuation duration, the more abnormal the plastic bottle pressure change. Therefore, the abnormality degree of the plastic bottle pressure is proportional to the delay degree and the fluctuation amplitude characteristic, and inversely proportional to the fluctuation duration difference characteristic and the maximum fluctuation duration. In an exemplary embodiment, a specific quantitative method for the abnormality degree of the plastic bottle pressure is given as follows:

[0076] ;

[0077] in, Indicates the abnormal degree of pressure in the plastic bottle, b indicates the fluctuation amplitude characteristic, Indicates the difference characteristics of fluctuation duration, Indicates the maximum fluctuation duration, Represents an exponential function with the natural constant e as the base. Abnormal degree of pressure in plastic bottles It reflects the abnormal pressure of the plastic bottle during the pressurization process. In order to accurately determine the sealing performance of the plastic bottle, it is necessary to further analyze the pressure changes during the pressure maintenance process of the plastic bottle.

[0078] Step 3: Determine the pressure drop characteristics of the plastic bottle during the pressure holding process.

[0079] During the pressure-maintaining process, no more gas will be injected into the plastic bottle. Under normal circumstances, the pressure inside the plastic bottle should always remain stable or decrease at an extremely slow rate. However, when there is a sealing problem with the plastic bottle, there will be a certain amount of gas leakage, and the pressure inside the plastic bottle will continue to decrease. The speed of the pressure drop is related to the severity of the sealing problem. The worse the sealing, the greater the leakage, and the faster the pressure drop. Therefore, the pressure drop characteristics of the plastic bottle during the pressure-maintaining process are obtained, and the pressure drop characteristics of the plastic bottle characterize the pressure drop of the plastic bottle during the pressure-maintaining process. It should be understood that if there is gas leakage during the pressure-maintaining stage, it may be that the plastic bottle has poor sealing and begins to leak when inflation stops, or it may be that some tiny holes slowly expand and break through the critical size after a period of time at the beginning of the pressure-maintaining stage, causing gas leakage.

[0080] In an exemplary embodiment, the pressure drop characteristic of the plastic bottle consists of two parts: the pressure drop speed characteristic and the pressure difference between the beginning and end of the pressure holding process. The pressure drop speed characteristic characterizes the speed of the pressure drop of the plastic bottle during the pressure holding process. Figure 3As shown, a specific process for obtaining the pressure drop rate characteristic is provided as follows:

[0081] Step 3-1: Determine the decreasing rate of each pressure value in the pressure change curve of the plastic bottle during the pressure holding process, and determine the average decreasing rate, the maximum decreasing rate, and the time when the maximum decreasing rate occurs.

[0082] The rate of decrease of each pressure value in the pressure change curve of the plastic bottle during the pressure-maintaining process is obtained. In this embodiment, the slope of each pressure value in the pressure change curve of the plastic bottle during the pressure-maintaining process is obtained. When the plastic bottle has no sealing problem, the pressure values ​​in the pressure change curve of the plastic bottle during the pressure-maintaining process always remain stable or decrease at an extremely slow rate. When the plastic bottle has a sealing problem, the pressure values ​​in the pressure change curve of the plastic bottle during the pressure-maintaining process continue to decrease. Therefore, the slope of each pressure value in the pressure change curve of the plastic bottle during the pressure-maintaining process is less than or equal to 0. In this embodiment, the absolute value of the slope of each pressure value is taken as the rate of decrease of each pressure value. Then, the larger the absolute value of the slope of each pressure value, the greater the rate of decrease of each pressure value.

[0083] Calculate the average value of the decrease rate of each pressure value in the pressure change curve of the plastic bottle during the pressure holding process as the average value of the decrease rate of the plastic bottle pressure during the pressure holding process. The larger the average value of the decrease rate, the faster the gas leakage rate in the plastic bottle and the more obvious the pressure decrease rate feature; obtain the maximum value of the decrease rate of each pressure value in the pressure change curve of the plastic bottle during the pressure holding process as the maximum decrease rate of the plastic bottle pressure during the pressure holding process. The occurrence of the maximum decrease rate can be understood as the sudden and greater leakage of gas due to the slow expansion of some tiny holes that break through the critical size after a period of time at the beginning of the pressure holding stage. The larger the maximum decrease rate, the faster the gas leakage rate in the plastic bottle and the more obvious the pressure decrease rate feature; obtain the occurrence time of the maximum decrease rate, and then obtain the time interval between the start time of the pressure holding process and the occurrence time of the maximum decrease rate as the occurrence time of the maximum decrease rate. The earlier the occurrence time, that is, the shorter the duration of the occurrence time, the faster the gas leakage rate in the plastic bottle and the more obvious the pressure decrease rate feature.

[0084] Step 3-2: Obtain the pressure drop rate characteristics based on the average drop rate, the maximum drop rate, and the time when the maximum drop rate occurs.

[0085] The pressure drop rate characteristic is obtained based on the average drop rate, the maximum drop rate, and the time when the maximum drop rate occurs. The pressure drop rate characteristic is proportional to the average drop rate and the maximum drop rate, and inversely proportional to the time when the maximum drop rate occurs. In an exemplary embodiment, a specific quantitative method for the pressure drop rate characteristic is given as follows:

[0086] ;

[0087] in, Indicates the pressure drop rate characteristics, represents the average value of the descent rate, Indicates the maximum descent rate, Indicates the duration of the maximum rate of decrease.

[0088] At the end of the pressure-holding process, the pressure of the remaining gas in the plastic bottle is related to the gas leakage rate, that is, it is related to the sealing performance of the plastic bottle. When the gas leaks quickly, it may leak out during the pressure-holding process, and the pressure in the plastic bottle drops to the ambient pressure; when the gas leaks slowly or there is no leakage, more gas will remain in the plastic bottle at the end of the pressure-holding process, and the pressure will still be at a high level. Therefore, the pressure difference at the beginning and end of the pressure-holding process is obtained, which is the difference between the two pressure values ​​at the beginning and end of the pressure-holding process. Specifically, the difference between the first pressure value and the last pressure value in the pressure change curve of the plastic bottle during the pressure-holding process is obtained as the pressure difference at the beginning and end of the pressure-holding process. The smaller the pressure difference at the beginning and end of the pressure-holding process, the less gas leaked during the pressure-holding process, and the better the sealing performance of the plastic bottle. In an exemplary embodiment, in order to facilitate subsequent processing, the pressure difference at the beginning and end of the pressure-holding process is normalized.

[0089] Step 4: Obtain the sealing performance index of the plastic bottle according to the abnormal degree of the plastic bottle pressure and the pressure drop characteristics of the plastic bottle.

[0090] The degree of abnormal pressure in a plastic bottle is an indicator obtained during the pressurization process that can characterize the sealing performance of the plastic bottle. The characteristic of the pressure drop in the plastic bottle is an indicator obtained during the pressure-maintaining process that can characterize the sealing performance of the plastic bottle. Combining these two indicators yields a plastic bottle sealing performance index. The higher the degree of abnormal pressure in the plastic bottle, the worse the sealing performance of the plastic bottle and the lower the sealing performance index of the plastic bottle. The higher the characteristic of the pressure drop in the plastic bottle, the worse the sealing performance of the plastic bottle and the lower the sealing performance index of the plastic bottle. In an exemplary embodiment, a specific method for quantifying the sealing performance index of the plastic bottle is given as follows:

[0091] ;

[0092] in, It is the sealing performance index of plastic bottles. It is the normalized pressure difference between the beginning and end of the pressure holding process. The higher the sealing performance index of the plastic bottle, the better the sealing performance of the plastic bottle.

[0093] When using the air pressure method to detect the sealing performance of a plastic bottle, if only a single plastic bottle is detected, the sealing performance of the plastic bottle can be misjudged due to gas escaping from the connection between the inflation device and the plastic bottle caused by a loose sealing ring or improper installation, or other interference such as gas leakage at the connection of the pressure sensor. In an exemplary embodiment, to solve the problem of misjudgment of the sealing performance of the plastic bottle caused by pressure abnormalities caused by other factors unrelated to the sealing performance of the plastic bottle, such as Figure 4 As shown in FIG. 1, the plastic bottle sealing performance detection method provided by the present embodiment further includes the following steps:

[0094] Step 5: Obtain the total pressure change curve of the plurality of plastic bottles.

[0095] The plurality of plastic bottles are plastic bottles of the same batch, which are usually produced by the same mold, raw materials and process, and theoretically have consistent sealing performance. In addition, the inflation device needs to be reinstalled every time the bottle is replaced, which can reduce the impact of accidental leakage caused by loose connections and poor contact of the pressure sensor. Therefore, the same detection needs to be performed on a plurality of plastic bottles of the same batch, and the sealing performance is determined according to the pressure change characteristics of the plastic bottles.

[0096] The total pressure change curve of each plastic bottle is obtained by connecting the pressure change curve of the plastic bottle during the pressurization process and the pressure change curve of the plastic bottle during the pressure maintaining process in time sequence.

[0097] Step 6: Determine the similarity between the total pressure change curve of the target plastic bottle and the total pressure change curve of each reference plastic bottle, and obtain the average similarity corresponding to the target plastic bottle.

[0098] For ease of illustration, the target plastic bottle is set as the plastic bottle to be tested, i.e., the plastic bottle to be tested is the object of sealing performance detection. Each plastic bottle other than the target plastic bottle is set as each reference plastic bottle. The plurality of plastic bottles obtained in step 5 include the target plastic bottle and each reference plastic bottle.

[0099] Obtain the similarity between the total pressure change curve of the target plastic bottle and the total pressure change curves of each reference plastic bottle. Since the time to reach the target pressure is not exactly the same for different plastic bottles, and the pressure change amplitude and pressure drop rate during the pressure holding process are not exactly the same, the lengths of the total pressure change curves of different plastic bottles may be different. In order to obtain the similarity, in an exemplary embodiment, for any reference plastic bottle, obtain the DTW (Dynamic Time Warping) distance between the total pressure change curve of the target plastic bottle and the total pressure change curve of the reference plastic bottle, and then perform negative correlation normalization on the DTW distance. The result obtained is the similarity between the total pressure change curve of the target plastic bottle and the total pressure change curve of the reference plastic bottle. The negative correlation normalization method is The similarities between the target bottle's overall pressure curve and the pressure curves of each reference bottle are then calculated. The average of these similarities is used as the mean similarity value for the target bottle. The larger the mean similarity value, the more similar the target bottle's pressure changes are to those of all other bottles.

[0100] In an exemplary embodiment, in order to ensure that the mean similarity value of the target plastic bottle is more consistent with the actual situation, after obtaining the mean similarity value of the target plastic bottle, as shown in FIG. Figure 5 As shown, the plastic bottle sealing detection method also includes the following process of correcting the similarity mean of the target plastic bottle:

[0101] Step 6-1: Determine the reference duration difference and total duration difference of the target plastic bottle.

[0102] Determine the reference duration of the target plastic bottle during the pressurization process and the total duration of the target plastic bottle, where the total duration of the target plastic bottle is the duration of the total pressure change curve of the target plastic bottle.

[0103] Obtain the target plastic bottle's reference duration difference. This is the difference between the target plastic bottle's reference duration and the standard reference duration, i.e., the absolute value of the difference. Obtain the target plastic bottle's total duration difference. This is the difference between the target plastic bottle's total duration and the standard total duration, i.e., the absolute value of the difference. The greater the difference between the target plastic bottle's reference duration difference and the total duration difference, the more abnormal the target plastic bottle's pressure fluctuations.

[0104] In an exemplary embodiment, Figure 6 As shown, the process of obtaining the standard reference duration and the standard total duration is given below, including:

[0105] Step 6-1-1: Obtain the key feature vectors of each reference plastic bottle.

[0106] For any reference plastic bottle, the reference duration and total duration of the reference plastic bottle are combined into a two-dimensional array, and the two-dimensional array is used as the key feature vector of the reference plastic bottle. In this way, the key feature vector of each reference plastic bottle is obtained.

[0107] Step 6-1-2: Cluster the reference plastic bottles according to the key feature vectors of each reference plastic bottle to obtain the cluster with the largest number of reference plastic bottles.

[0108] According to the key feature vectors of each reference plastic bottle, the reference plastic bottles are clustered to obtain the cluster with the largest number of reference plastic bottles. In an exemplary embodiment, the Euclidean distance of the key feature vectors of every two reference plastic bottles is obtained, and then the reference plastic bottles are clustered using the K-means clustering algorithm based on the Euclidean distance. The K value in the K-means clustering algorithm can be obtained by the elbow method. K clusters are obtained by the K-means clustering algorithm. Each cluster contains a number of reference plastic bottles, so as to obtain the number of reference plastic bottles contained in each cluster, obtain the cluster containing the largest number of reference plastic bottles, that is, obtain the cluster with the largest number of reference plastic bottles. The cluster with the largest number of reference plastic bottles can characterize the most common feature of the reference plastic bottles and can be used as a standard. Therefore, each reference plastic bottle in the cluster with the largest number of reference plastic bottles is recorded as a standard reference plastic bottle, and the number of standard reference plastic bottles is determined. The total number of reference plastic bottles is obtained, and the ratio of the number of standard reference plastic bottles to the total number of reference plastic bottles is calculated as the proportion of the number of standard reference plastic bottles, that is, the proportion of the number of reference plastic bottles in the cluster with the largest number of reference plastic bottles.

[0109] Step 6-1-3: The average value of the reference durations of the reference plastic bottles in the cluster is used as the standard reference duration, and the average value of the total durations of the reference plastic bottles in the cluster is used as the standard total duration.

[0110] Calculate the average reference duration of each reference plastic bottle in the cluster with the largest number of reference plastic bottles, that is, calculate the average reference duration of each standard reference plastic bottle, and use it as the standard reference duration. Calculate the average total duration of each reference plastic bottle in the cluster with the largest number of reference plastic bottles, that is, calculate the average total duration of each standard reference plastic bottle, and use it as the standard total duration.

[0111] Step 6-2: Based on the reference time difference and the total time difference of the target plastic bottle, obtain a correction coefficient of the target plastic bottle.

[0112] According to the reference time difference and total time difference of the target plastic bottle, as well as the proportion of the number of standard reference plastic bottles, the correction coefficient of the target plastic bottle is obtained. The correction coefficient is used to make a positive correction to the similarity mean corresponding to the target plastic bottle. Since the smaller the reference time difference and total time difference of the target plastic bottle, the smaller the difference between the pressure change characteristics of the target plastic bottle and the standard pressure change characteristics, the more similar the pressure change characteristics of the target plastic bottle are to all other plastic bottles in the same batch, and the larger the correction coefficient; the proportion of the number of standard reference plastic bottles represents the credibility of the standard reference plastic bottle, the larger the proportion of the number of standard reference plastic bottles, the higher its credibility, and the larger the correction coefficient. Therefore, the correction coefficient is proportional to the proportion of the number of standard reference plastic bottles, and inversely proportional to the reference time difference and the total time difference. In an exemplary embodiment, a specific quantitative method for the correction coefficient of the target plastic bottle is given as follows:

[0113] ;

[0114] in, represents the correction factor, Indicates the proportion of standard reference plastic bottles, Indicates the reference duration difference, Indicates the total duration difference.

[0115] Finally, the obtained correction coefficient is multiplied by the mean similarity value corresponding to the target plastic bottle, and the result obtained is the corrected mean similarity value of the target plastic bottle.

[0116] Step 7: The plastic bottle sealing performance index and the similarity mean of the target plastic bottle are integrated to obtain the final plastic bottle sealing performance index of the target plastic bottle.

[0117] The product of the target plastic bottle's sealing performance index and the corrected similarity mean is calculated to obtain the final plastic bottle sealing performance index of the target plastic bottle. A higher final plastic bottle sealing performance index value indicates better sealing performance of the target plastic bottle, while a lower final plastic bottle sealing performance index value indicates worse sealing performance of the target plastic bottle.

[0118] In one exemplary embodiment, a threshold is preset to determine whether the target plastic bottle's sealing performance meets the requirements. This threshold ranges from 0 to 1, with the specific value set based on actual judgment needs. The more stringent the judgment, the higher the threshold can be set. This embodiment uses 0.8 as an example. If the target plastic bottle's final sealing performance index is greater than or equal to 0.8, the target plastic bottle's sealing performance meets the requirements. Otherwise, the target plastic bottle's sealing performance fails.

[0119] In an exemplary embodiment, this embodiment also provides a plastic bottle sealing detection device, including: a computer-readable storage medium, the computer-readable storage medium storing a computer program, and the computer program, when executed by a processor, implements the steps in the above-mentioned plastic bottle sealing detection method embodiment.

[0120] In an exemplary embodiment, this embodiment also provides a plastic bottle sealing detection system, including: a memory and a processor; the memory is connected to the processor, and the memory is used to store program instructions; the processor is used to implement the steps in the above-mentioned plastic bottle sealing detection method embodiment when the program instructions are executed.

[0121] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0122] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A method for detecting the sealing property of a plastic bottle, characterized in that: include: Obtain the delay between the actual pressure of the plastic bottle reaching the target pressure during the pressurization process of the plastic bottle; Determine the pressure fluctuation of the plastic bottle during the pressurization process, and obtain the abnormality of the pressure of the plastic bottle during the pressurization process in combination with the delay degree; determining a pressure drop characteristic of the plastic bottle during the pressure-maintaining process, wherein the pressure drop characteristic of the plastic bottle represents a decrease in the pressure of the plastic bottle during the pressure-maintaining process; Obtaining a sealing performance index of the plastic bottle according to the abnormal pressure degree of the plastic bottle and the pressure drop characteristics of the plastic bottle; The plastic bottle sealing detection method further comprises: Obtaining a total pressure change curve of a plurality of plastic bottles, wherein the total pressure change curve is composed of the pressure change curves of the plastic bottles during the pressurization process and the pressure holding process; Determine the similarity between the total pressure change curve of a target plastic bottle and the total pressure change curves of each reference plastic bottle, and obtain a similarity mean corresponding to the target plastic bottle; the target plastic bottle is a plastic bottle to be tested; the reference plastic bottles are each plastic bottle other than the target plastic bottle; the plurality of plastic bottles includes the target plastic bottle and the reference plastic bottles; Fusion of the plastic bottle sealing performance index and the similarity mean of the target plastic bottle to obtain a final plastic bottle sealing performance index of the target plastic bottle; After obtaining the similarity mean, the plastic bottle sealing detection method further includes: Determine a reference duration difference and a total duration difference of the target plastic bottle, wherein the reference duration difference is the difference between the reference duration of the target plastic bottle and the standard reference duration, and the total duration difference is the difference between the total duration of the target plastic bottle and the standard total duration; the reference duration is the pressurization duration when a reference pressure appears, and the reference pressure is the pressure value closest to the target pressure that appears for the first time during the pressurization process; and the total duration is the duration of the total pressure change curve; Based on the reference duration difference and the total duration difference of the target plastic bottle, a correction coefficient of the target plastic bottle is obtained, and the correction coefficient is used to correct the similarity mean corresponding to the target plastic bottle.

2. A method for detecting the sealing property of a plastic bottle as claimed in claim 1, characterized in that: The process of obtaining the standard reference duration and the standard total duration includes: Obtaining a key feature vector of each reference plastic bottle, wherein the key feature vector is composed of a reference duration and a total duration of the reference plastic bottle; Cluster the reference plastic bottles according to the key feature vectors of each reference plastic bottle to obtain the cluster with the largest number of reference plastic bottles; The average value of the reference durations of the reference plastic bottles in the cluster is used as the standard reference duration, and the average value of the total durations of the reference plastic bottles in the cluster is used as the standard total duration; The correction coefficient of the target plastic bottle is obtained based on the reference time difference and the total time difference of the target plastic bottle, including: A correction coefficient of the target plastic bottle is obtained based on the reference time difference and the total time difference of the target plastic bottle, as well as the proportion of the number of reference plastic bottles in the cluster; the correction coefficient is proportional to the proportion of the number of reference plastic bottles, and inversely proportional to the reference time difference and the total time difference.

3. A method for detecting the sealing property of a plastic bottle as claimed in claim 1, characterized in that: The process of obtaining the delay degree includes: Obtaining a reference pressure and a reference duration of the plastic bottle during the pressurization process, wherein the reference pressure is a pressure value closest to the target pressure that appears for the first time during the pressurization process, and the reference duration is the pressurization duration when the reference pressure appears; The degree of delay is obtained based on the pressure difference and the duration difference; the degree of delay is proportional to both the pressure difference and the duration difference, the pressure difference being the difference between the target pressure and the reference pressure, and the duration difference being the difference between the reference duration and the theoretical duration.

4. A method for detecting the sealing property of a plastic bottle as claimed in claim 1, characterized in that: The process of obtaining the pressure fluctuation of the plastic bottle includes: Determine the average value of each fluctuation amplitude in the pressure change curve of the plastic bottle during the pressurization process to obtain a fluctuation amplitude feature, wherein the fluctuation amplitude is the pressure difference between adjacent peaks and troughs; Determine the average value of the difference between any two fluctuation durations in the pressure change curve of the plastic bottle during the pressurization process to obtain a fluctuation duration difference feature, where the fluctuation duration is the time interval between adjacent peaks and troughs; The maximum value of all the fluctuation durations is determined to obtain the maximum fluctuation duration.

5. A method for detecting the sealing property of a plastic bottle as claimed in claim 4, characterized in that: The process of obtaining the abnormal pressure level of the plastic bottle includes: The abnormal degree of the plastic bottle pressure is obtained according to the delay degree, fluctuation amplitude characteristics, fluctuation duration difference characteristics and maximum fluctuation duration; the abnormal degree of the plastic bottle pressure is proportional to the delay degree and fluctuation amplitude characteristics, and inversely proportional to the fluctuation duration difference characteristics and maximum fluctuation duration.

6. A method for detecting the sealing property of a plastic bottle as claimed in claim 1, characterized in that: The pressure drop characteristic of the plastic bottle includes a pressure drop speed characteristic, and the process of obtaining the pressure drop speed characteristic includes: Determine the decreasing rate of each pressure value in the pressure change curve of the plastic bottle during the pressure holding process, and determine the average decreasing rate, the maximum decreasing rate, and the time when the maximum decreasing rate occurs; The pressure drop rate characteristic is obtained according to the average drop rate, the maximum drop rate and the occurrence time of the maximum drop rate. The pressure drop rate characteristic is proportional to the average drop rate and the maximum drop rate, and inversely proportional to the occurrence time.

7. A plastic bottle sealing detection device, characterized in that: The invention comprises a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps in the method for detecting the sealing property of a plastic bottle according to any one of claims 1 to 6.

8. A plastic bottle sealing detection system, comprising: Memory and processor; The memory is connected to the processor; The memory is used to store program instructions; The processor is configured to implement the plastic bottle sealing detection method according to any one of claims 1 to 6 when the program instructions are executed.

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