Device and method for online detection of triacetin homogeneity in filter rods

Abstract

The present application relates to filter rod forming online detection technical field, specifically disclose a result reliable, strong real-time online detection filter rod in triacetin uniformity device, including for online detection production in forming filter rod optical density detection module, and processing optical density detection module provided optical density signal signal processing module, signal processing module includes converting the optical density signal of electric signal into digital signal analog-digital conversion unit, the digital signal provided by analog-digital conversion unit is separated into high-frequency and low-frequency signal data separation unit, and for calculating uniformity judgment value according to the amplitude, frequency, phase, phase shift, phase change amplitude and the time length of influence of high-frequency signal and low-frequency signal calculation unit. Also disclosed is a kind of to the online detection filter rod in triacetin uniformity method of above-mentioned device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of filter rod detection, in particular to a device and method for detecting the uniformity of triacetin or other attachments or impurities in filter rods by optical density method. BACKGROUND

[0002] Triacetin is often used as a plasticizer and curing agent in the filter rod forming process, which is added and attached to cellulose acetate to form a certain network structure between the opened filaments, so that the filter rod can achieve sufficient hardness after curing. The uniformity of triacetin added in the filaments is one of the main factors affecting the smoking resistance and quality stability of cigarettes. At present, there are few online monitoring means for the uniformity of triacetin in the tobacco processing industry. The detection is usually carried out by sampling the processed filter rod and measuring the dry and wet rod or using gas chromatography method. The sampling and processing operation of the filter rod requires high requirements, and the value of the empirical value in the calculation directly determines the effectiveness of the detection result. The accuracy and reliability of the detection result are insufficient. Moreover, this scheme can only realize the detection of a small part of the filter rod, and the risk of missing the unqualified product is large. The detection result cannot reflect the true situation of the filter rod. In addition, this detection method has a certain lag. When it is found that the triacetin added in the filter rod is not uniform, the unqualified filter rod is often mixed with qualified products, which is not easy to detect, and thus it is difficult to meet the requirements of large-scale production of filter rods in industry. SUMMARY

[0003] Therefore, it is necessary to provide a device and method for online detection of the uniformity of triacetin or other attachments or impurities in filter rods, which has reliable results and strong real-time performance.

[0004] The device for online detection of the uniformity of triacetin in filter rods comprises:

[0005] The optical density detection module for online detection of the moving forming filter rod, and the signal processing module for processing the optical density signal provided by the optical density detection module, the signal processing module comprises an analog-to-digital conversion unit for converting the optical density signal of the electrical signal into a digital signal, a data separation unit for separating the digital signal provided by the analog-to-digital conversion unit into high-frequency and low-frequency signals, and a calculation unit for calculating the uniformity judgment value according to the amplitude, frequency, phase, phase shift, phase change amplitude and time length of influence of the high-frequency signal and the low-frequency signal.

[0006] In one of the embodiments, the device for detecting the uniformity of triacetin in the filter rod in line further comprises a coding module for selecting the continuously produced filter rod and dividing it into a plurality of continuous filter rod segments to be detected, and the optical density detection module detects the uniformity of triacetin in each filter rod segment to be detected one by one, and the length of each filter rod segment is 0.05-150 mm.

[0007] In one of the embodiments, the device for detecting the uniformity of triacetin in the filter rod in line further comprises a non-conforming product processing module connected with the signal processing module, and the non-conforming product processing module comprises a rejection module for rejecting the filter rod segment with non-uniform triacetin, and when the rejection module rejects the filter rod segment with non-uniform triacetin, the coding module receives the signal sent by the signal processing module and marks the filter rod segment with non-uniform triacetin as a non-control sample segment.

[0008] In one of the embodiments, the optical density detection unit comprises a light source, a coupling light path for acting the light source on the filter rod, a converging light path for converging the light signal from the filter rod, and an ultra-high-speed spectrometer or a photoelectric element for performing spectral analysis on the light converged by the converging light path.

[0009] In one of the embodiments, the coding module controls the high-speed light source in the optical density detection unit to perform intermittent light detection on the selected filter rod in motion according to the motion speed of the filter rod, and the filter rod is divided into a plurality of continuous filter rod segments to be detected by the adjacent two light detections, and the length of each filter rod segment to be detected is 0.1-1 mm.

[0010] The application further discloses a method for detecting the uniformity of triacetin in a filter rod in line, which comprises the following steps:

[0011] S1: obtaining the optical density signal of the filter rod segment in motion by the optical density detection module;

[0012] S2: converting the optical density electrical signal into a digital signal;

[0013] S3: separating the digital signal into a high-frequency signal and a low-frequency signal;

[0014] S4: comparing the amplitude, frequency, phase and phase shift of the high-frequency signal and the low-frequency signal;

[0015] S5: obtaining the triacetin uniformity judgment value of the filter rod according to the changed amplitude and the length of the affected time.

[0016] In one of the embodiments, in step S3, the signal with a frequency greater than a predetermined reference frequency is separated into a high-frequency signal by wavelet transform or mean value method, and the rest is a low-frequency signal.

[0017] In one embodiment, the reference frequency is 800 Hz.

[0018] In one embodiment, the method further comprises, before step S1:

[0019] T1) spraying plasticizer on the tow in high speed motion;

[0020] T2) the tow after spraying is concentrated and narrowed to form a paperless filter rod;

[0021] T3) step S1 detects the uniformity of the plasticizer in the paperless filter rod.

[0022] In one embodiment, step S5 further comprises: rejecting the filter rod segment with non-uniform triacetin and marking it as a non-control sample segment.

[0023] The device and method for online detection of triacetin uniformity in filter rods according to the present application use the method of optical density measurement to measure the optical density of each segment of the filter rod in motion in real time, and through signal conversion and frequency division processing, calculate the uniformity judgment value of each segment of the filter rod. Through online segment-by-segment detection of the filter rod, on the one hand, the problem of missed detection of unqualified products is avoided, so that the detection result truly reflects the actual product, and on the other hand, the online detection of the filter rod facilitates the timely rejection of unqualified products, avoids the mixing of qualified products and unqualified products, is beneficial to workshop management, and can meet the requirements of large-scale production of filter rods in industry. The method and device of the present application can also be used to detect the uniformity of the attached matter other than triacetin in the filter rod and the impurity in the filter rod. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The flowchart of the triacetin uniformity online detection method in one embodiment of the present application;

[0025] Figure 2 The schematic diagram of the segmentation of the filter rod in one embodiment of the present application;

[0026] Figure 3 The module diagram of the triacetin uniformity online detection device in one embodiment of the present application;

[0027] Figure 4 The schematic diagram of the scene during the triacetin uniformity online detection in one embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the drawings. In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0029] The present application is directed to the difficulty of operation, the lack of accuracy and reliability of results, the risk of missing unqualified products, and the lag of detection results in the measurement of the uniformity of triacetin in conventional filter rods, but not limited to triacetin (hereinafter the same, in the present application, triacetin can refer to any substance attached to the filter rod). A device and method for measuring the uniformity of triacetin in filter rods by optical density measurement. The basis for the present application to detect the uniformity of triacetin in filter rods by optical density method is that at present, when the filter rod is processed in the workshop, the filament passes through the spraying device of the filter rod forming machine at a speed of about 10 m / s, the spraying device is full of atomized small triacetin droplets, after passing through the spraying device, a number of small droplets will be formed on the filament, then the filament is collected to form a filter rod, when light passes through the filter rod droplets, reflection and refraction phenomena will occur. In this way, when the triacetin in the filter rod is sprayed unevenly, there will be three situations: local dryness (i.e. no triacetin exists), local semi-dryness (i.e. low concentration of triacetin), and local supersaturation (i.e. high concentration of triacetin). In this way, when light passes through the filter rod, the transmission of light is larger at the place where the concentration of triacetin is too high, and the transmission of light is smaller at the dry or semi-dry parts of the filter rod. In this way, by measuring the transmission of light through the filter rod and combining the incident amount of light into the filter rod (i.e. detecting the optical density of the filter rod), it can be judged whether there is droplet convergence or local dryness in the filter rod, that is, the uniformity of triacetin sprayed on the filter rod can be judged.

[0030] Specifically, please refer to Figure 1 and Figure 4 The present embodiment provides a method 10 for online detection of the uniformity of triacetin in filter rods, which has reliable results and strong real-time performance, the method comprising the following steps:

[0031] S1: obtaining the optical density signal of the moving finished filter rod segment by the optical density detection module.

[0032] Before step S1, it further comprises:

[0033] T1) spraying the plasticizer on the high-speed moving filament.

[0034] T2) The sprayed filament is collected and narrowed to form a paperless filter rod.

[0035] T3)The filter rod is shaped by the upper and lower smoke guns, and the filter rod shaped by the upper and lower smoke guns is subjected to the plasticizer uniformity detection of step S1.

[0036] Specifically, in the embodiment, the continuously produced filter rods are selected, and the filter rods are divided into continuous filter rod segments to be detected. In the embodiment, the filter rods to be detected are divided into small segments of about 0.5 mm (as shown in the figure), that is, the method of the embodiment is to detect the optical density of the filter rod segments of 0.5 mm / segment one by one, so as to improve the detection accuracy of the filter rods and further improve the reliability of the detection results. In the embodiment, the division of the filter rods into continuous filter rod segments to be detected is realized by a rotary encoder. Figure 2

[0037] S2: Convert the optical density electrical signal into a digital signal.

[0038] S3: Separate the digital signal into a high-frequency signal and a low-frequency signal.

[0039] In step S3, the signal with a frequency greater than a predetermined reference frequency of 800 Hz is separated into a high-frequency signal by wavelet transform or mean value method, and the rest is a low-frequency signal. In other embodiments, the reference frequency can also be adjusted according to the specific situation of production, which will not be described here.

[0040] S4: Compare the amplitude, frequency, phase, and phase shift of the high and low frequency signals.

[0041] S5: Obtain the triacetin uniformity judgment value of the filter rod according to the changed amplitude and the length of time of the influence.

[0042] It should be noted that during the optical density detection of the filter rod, an optical density reference value for calculating the triacetin uniformity judgment value of the filter rod also needs to be set.

[0043] Specifically, the optical density passing through the current filter rod segment to be detected is detected, and it is judged whether it is the first detection. If not, the normal detection process is entered. When it is judged that it is the first detection, the filter rod produced by the current filter rod forming machine is selected, and the optical density of continuous M filter rod segments on the filter rod is measured. The optical density of the M filter rod segments is processed to obtain an initial optical density reference value. When it is judged that it is not the first detection, the optical density of all uniformity qualified filter rod segments before the current filter rod segment to be detected and the optical density of M filter rod segments on the filter rod produced by the current filter rod forming machine are selected, and the optical density reference value is obtained after processing.

[0044] ​It should be noted that when the device is first used to detect the filter rod after leaving the factory, the device is powered on, and the optical density of the M filter rod segments on the filter rod is detected first (none of the filter rod segments are rejected after detection), and the initial optical density reference value is obtained by calculating the filter value or the average value. When the M+1th filter rod segment is detected, the initial optical density reference value obtained from the previous M filter rod segments is taken to evaluate the triacetin uniformity of the M+1th filter rod segment.

[0045] When entering the normal detection process, at least M filter rod segments before the current filter rod segment to be detected are selected as the reference sample, the optical density of each filter rod segment passing through the reference sample is detected, and the optical density of the M filter rod segments is processed to obtain the optical density reference value. Preferably, M is any integer value between 2 and 10000. In this embodiment, the optical density of the M filter rod segments is processed to obtain the optical density reference value, which includes taking the average value or the filter value of the optical density of the M filter rod segments as the optical density reference value, that is, the average value or the filter value is used to obtain the optical density reference value.

[0046] The optical density of the current filter rod segment to be detected is compared with the optical density reference value, and the uniformity of triacetin in the current filter rod segment to be detected is determined. In this embodiment, the uniformity index U is set as [ (the optical density of the current filter rod segment to be detected - the optical density reference value) / the optical density reference value] x 100%, and the standard value of | uniformity index U | is set as 40%. When | uniformity index U | ≥ 40%, it is determined that the uniformity of triacetin in the current filter rod segment to be detected is unqualified, that is, the triacetin in the current filter rod segment to be detected is not sprayed uniformly. When | uniformity index U | < 40%, it is determined that the uniformity of triacetin in the current filter rod segment to be detected is qualified, that is, the triacetin in the current filter rod segment to be detected is sprayed uniformly. In other embodiments, according to the quality requirements of the product and the working conditions and material requirements, the fluctuation value of the uniformity index U can also be adjusted. For example, when the quality requirement of the product is high, the absolute value of the uniformity index U can be limited within 20%, and when the quality requirement of the product is wide, the absolute value of the uniformity index U can be limited within 50%. In addition, the standard value of | uniformity index U | can also be adjusted according to the actual situation. That is, in this embodiment, the triacetin uniformity judgment value of the filter rod is obtained according to the change amplitude and the time length of the influence, that is, the calculation of the uniformity index U, and the final calculation of the triacetin uniformity judgment value of the filter rod includes two cases, that is, 1 and 0. When the triacetin uniformity judgment value of the filter rod is 0, that is, | uniformity index U | is greater than the corresponding standard value, the uniformity of the filter rod is unqualified at this time. When the triacetin uniformity judgment value of the filter rod is 1, that is, | uniformity index U | is within the corresponding standard value range, the uniformity of the filter rod is qualified at this time.

[0047] Subsequently, the above first detection, normal detection and uniformity judgment processes are repeated to detect each of the to-be-detected segments one by one until all the to-be-detected segments of the filter rod are detected.

[0048] In the embodiment, the optical density measurement method for the current to-be-detected filter rod segment is the same as the optical density detection method for the M filter rod segments before the current to-be-detected filter rod segment. Specifically, the optical density detection of the filter rod segment includes:

[0049] Collecting the incident light intensity I0 before the light source passes through the filter rod segment and the transmitted light intensity I after the light source passes through the filter rod segment;

[0050] Calculating the optical density OD of the filter rod segment according to the following formula:

[0051] The optical density OD = lg (incident light intensity I0 / transmitted light intensity I).

[0052] In the embodiment, the incident light intensity I0 is determined by the light intensity signal output by the light source, and the transmitted light intensity I is determined by the light intensity signal received by the light receiving device. In order to improve the accuracy of the detection result, a coupling light path is arranged between the light source and the filter rod, and a converging light path is arranged between the filter rod and the light receiving device. In this way, the light path is constrained, the light intensity of the incident light and the transmitted light is concentrated, and the signal-to-noise ratio and the signal strength of the light signal are improved, so that the light intensity signal output by the light source can truly reflect the incident light intensity I0, and the light intensity signal received by the light receiving device can truly reflect the transmitted light intensity I. Preferably, in the embodiment, the coupling light path and the converging light path are respectively a lens or a lens combination.

[0053] Further, in the detection process of the optical density of the filter rod segment, the light source is a halogen light source or a laser; the spectrum of the light source is visible light or infrared light; the measurement of the optical density uses a photosensitive element or a spectrometer; the emission of the light source uses fiber autocollimation or a slit, and the reception of the light uses an integrating sphere, a slit or an optical fiber. Preferably, in the embodiment, the light source uses a laser, the spectrum of the light source is infrared light, the measurement of the optical density uses a super-speed spectrometer, the emission of the light source uses fiber autocollimation, and the reception of the light uses an optical fiber.

[0054] Since the purpose of the triacetin uniformity detection in the filter rod is to select unqualified products, and the optical density control value for evaluating the triacetin uniformity is for at least M filter rod segments before the current to-be-detected filter rod segment, after completing the uniformity detection of each filter rod segment on the filter rod, the optical density control value for the uniformity detection of the next filter rod segment needs to be adjusted. Therefore, step S5 further includes: rejecting the filter rod segment with non-uniform triacetin and marking it as a non-control sample segment.

[0055] The method for detecting the triacetin uniformity in the filter rod on-line is described below with reference to specific examples.

[0056] Specifically, the detection object of the embodiment is the filter rod which is not cut into segments. According to the moving speed of the filter rod and the working parameters of the optical density detection device, the length of the filter rod segment for each detection is set to 0.5 mm. When the first filter rod segment on the filter rod, i.e., the filter rod segment with a length of 0.5 mm from the first end of the filter rod, is measured, the filter rod processed by the current filter rod making machine (which may contain a filter rod segment with unqualified uniformity) is first selected to measure the optical density of the filter rod, i.e., to measure the optical densities of M continuous filter rod segments on the filter rod. The optical densities of the M filter rod segments are processed, and the average value or the filtered value thereof is taken as the optical density reference value.

[0057] To improve the accuracy of the optical density reference value, the optical densities of the filter rods with qualified uniformity (in the embodiment, the number of effective filter rod segments used to calculate the optical density reference value is 100) can be detected and the average value thereof is taken as the optical density reference value C1. After the optical density D1 of the first filter rod segment on the filter rod to be detected is measured, the optical density D1 is compared with the optical density reference value C1 obtained previously. If the calculated |uniformity index U| is greater than or equal to 40%, the first filter rod segment in the filter rod has unqualified uniformity, and the filter rod segment is rejected and marked as a non-reference sample segment. If the |uniformity index U| is between 15% and 40%, an alarm is given to prompt the staff. If the |uniformity index U| is between 15% and 40% for multiple times, the filter rod detection operation can be paused while the alarm is given. In the embodiment, the filter rod detection operation is paused if the |uniformity index U| is between 15% and 40% for more than 3 times. In this way, when the second filter rod segment on the filter rod is detected, the optical density D2 of the second filter rod segment is still compared with the optical density reference value C1 obtained by averaging.

[0058] If the |uniformity index U| calculated based on the optical density D1 of the first filter rod segment is less than 40%, the first filter rod segment in the filter rod has qualified uniformity. When the second filter rod segment on the filter rod is detected, the average value of the original optical density reference value C1 and the optical density D1 of the first filter rod segment (the average value is obtained by dividing the sum of the optical densities of 100 qualified filter rod segments processed by the filter rod making machine and the optical density of the first filter rod segment to be detected by 101, i.e., the moving average value) is taken as the new optical density reference value C2. The optical density D2 of the second filter rod segment is compared with the optical density reference value C2, and the above operations are repeated in sequence.

[0059] When it is judged that it is not the first detection, the optical density of all the uniformity qualified filter rod segments before the current filter rod segment to be detected and the optical density of the Mth filter rod segment on the filter rod processed by the current filter rod making machine are selected, and after processing, the optical density reference value is obtained. For example, if there are N uniformity qualified filter rod segments before the current filter rod segment to be detected, the average value or the filter value of the optical density of the N uniformity qualified filter rod segments and the Mth filter rod segment used for obtaining the initial optical density reference value is taken as the reference value for evaluating the uniformity of the current filter rod segment.

[0060] When the 101th filter rod segment of the current filter rod is detected, and the first 100 filter rod segments of the filter rod are all qualified filter rod segments, the optical density D101 of the 101th filter rod segment is measured, and the average value of the optical density of the 1-100th filter rod segments on the filter rod and the optical density of the Mth filter rod segment used for obtaining the initial optical density reference value is taken as the new optical density reference value C101. The optical density D101 is compared with the optical density reference value C101. If the |uniformity index U| of the 101th filter rod segment is greater than or equal to 40%, the 101th filter rod segment is rejected, the optical density of the 102th filter rod segment is measured, the optical density D102 of the 102th filter rod segment is obtained, and the optical density D102 is compared with the optical density reference value C101. If the |uniformity index U| of the 101th filter rod segment is less than 40%, the optical density of the 102th filter rod segment is measured, the optical density D102 of the 102th filter rod segment is obtained, and the average value of the optical density of the 1-101th filter rod segments and the optical density of the Mth filter rod segment used for obtaining the initial optical density reference value is taken as the new optical density reference value C102. The optical density D102 is compared with the optical density reference value C102, and the above operation is repeated until the detection of the last filter rod segment on the filter rod is completed.

[0061] Due to the influence of the filter rod making machine working condition and the filter rod segment material during the processing of the filter rod, the quality of the filter rod has slight fluctuations. If the same optical density reference value is used to calculate and judge the triacetin uniformity of different filter rod segments on the filter rod, the detection result will deviate from the actual situation of the product. In the embodiment, the optical density reference value changes with the movement of the filter rod segment during the judgment of the uniformity of each filter rod segment on the filter rod, the real-time adjustment of the optical density reference value is realized, and the optical density reference value can change with the fluctuation of the processing working condition and the material of the filter rod segment, and can more truly reflect the processing quality of the product.

[0062] Please refer to Figure 3 and Figure 4 , the application further discloses an online detection device 20 for detecting the triacetin uniformity in a filter rod, which comprises:

[0063] The coding module 210 is used to select the continuously produced filter rod and divide it into continuous filter rod segments for detection. In this embodiment, the length of each filter rod segment is 0.05-150 mm. Preferably, the filter rod to be detected is divided into small segments of 0.5 mm (as shown in Figure 2 That is, the method of this embodiment is to detect the optical density of the filter rod segments one by one, thereby improving the detection accuracy of the filter rod and further improving the reliability of the detection result. Preferably, the coding module 210 is a rotary encoder.

[0064] The optical density detection module 220 is used to detect the moving formed filter rod online. The optical density detection module 220 detects the optical density of each filter rod segment to be detected one by one, including the optical density of the current filter rod segment to be detected and the optical density of M uniformity qualified filter rod segments before the current filter rod segment to be detected. Preferably, M is an arbitrary integer value between 2 and 10000.

[0065] It should be noted that in an embodiment, the coding module 210 controls the high-speed light source in the optical density detection unit 220 to intermittently detect the selected moving filter rod. Adjacent two light detections divide the filter rod into a plurality of continuous filter rod segments to be detected, and the length of each filter rod segment to be detected is 0.1-1 mm.

[0066] The signal processing module 230 is used to process the optical density signal provided by the optical density detection module 220. The signal processing module 230 includes an analog-to-digital conversion unit for converting the optical density signal of the electrical signal into a digital signal, a data separation unit for separating the digital signal provided by the analog-to-digital conversion unit into high-frequency and low-frequency signals, and a calculation unit for calculating the uniformity judgment value according to the amplitude, frequency, phase, phase shift, phase change amplitude and time length of influence of the high-frequency signal and the low-frequency signal.

[0067] The calculation unit is also used to determine whether it is the first detection. If not, at least the optical density of M uniformity qualified filter rod segments before the current filter rod segment to be detected is selected for processing to obtain an optical density reference value. The optical density of the current filter rod segment to be detected is compared with the optical density reference value, and the uniformity of the triacetin in the current filter rod segment to be detected is judged. In this embodiment, the calculation unit takes the average value or the filtering value of the optical density of M filter rod segments as the optical density reference value, that is, the average value or the filtering value is used to obtain the optical density reference value.

[0068] In the embodiment, the computing unit selects a filter rod produced by the current filter rod making machine when determining that it is the first detection, measures the optical densities of M continuous filter rod segments on the filter rod, processes the optical densities of the M filter rod segments to obtain the optical density reference value; the computing unit selects the optical densities of all the uniformity qualified filter rod segments before the current filter rod segment to be detected and the optical densities of M filter rod segments on the filter rod processed by the current filter rod making machine when determining that it is not the first detection, processes the optical densities to obtain the optical density reference value.

[0069] In the embodiment, the uniformity index U is set as [ (the optical density of the current filter rod segment to be detected - the optical density reference value) / the optical density reference value] x 100%, the standard value of | the uniformity index U | is set as 40%, when | the uniformity index U | ≥ 40%, it is determined that the uniformity of the triacetin in the current filter rod segment to be detected is unqualified, i.e. the triacetin is not sprayed uniformly in the current filter rod segment to be detected; when | the uniformity index U | < 40%, it is determined that the uniformity of the triacetin in the current filter rod segment to be detected is qualified, i.e. the triacetin is sprayed uniformly in the current filter rod segment to be detected. In other embodiments, the fluctuation value of the uniformity index U can also be adjusted according to the quality requirements of the product, the working conditions and the material requirements, for example, when the product quality requirement is high, the absolute value of the uniformity index U can be limited within 20%, when the product quality requirement is wide, the absolute value of the uniformity index U can be limited within 50%. In addition, the standard value of | the uniformity index U | can also be adjusted according to the actual situation.

[0070] In the embodiment, the optical density detection device of the current filter rod segment to be detected and the optical density detection device of the M filter rod segments before the current filter rod segment to be detected are the same. Specifically, the optical density detection module 220 includes a light source, a coupling light path for acting the light source on the filter rod, a converging light path for converging the light signal from the filter rod and an ultra-high-speed spectrometer or a photoelectric element for performing spectral analysis on the light converged by the converging light path. The optical density detection module 220 further includes:

[0071] The signal acquisition module 221 is configured to acquire the incident light intensity I0 of the light source before passing through the filter rod segment and the transmitted light intensity I of the light source after passing through the filter rod segment.

[0072] The computing module 222 is configured to calculate the optical density OD of the filter rod segment according to the following formula:

[0073] The optical density OD = lg (incident light intensity I0 / transmitted light intensity I).

[0074] In the embodiment, the incident light intensity I0 is determined by the light intensity signal output by the light source, and the transmission light intensity I is determined by the light intensity signal received by the optical density detection module 220. In order to improve the accuracy of the detection result, a coupling light path is arranged between the light source and the filter rod, and a converging light path is arranged between the filter rod and the optical density detection module 220. In this way, the light path is constrained, the light intensity of the incident light and the transmission light is concentrated, and the signal-to-noise ratio and the signal strength of the light signal are improved, so that the light intensity signal output by the light source can truly reflect the incident light intensity I0, and the light intensity signal received by the optical density detection module 220 can truly reflect the transmission light intensity I. Preferably, in the embodiment, the coupling light path and the converging light path are respectively a lens or a lens combination.

[0075] Further, the light source is a halogen light source or a laser; the spectrum of the light source is visible light or infrared light; the optical density detection module 220 adopts a photosensitive element or a spectrometer; the emission of the light source adopts fiber autocollimation or a slit, and the reception of the light adopts an integrating sphere, a slit or an optical fiber. Preferably, in the embodiment, the light source adopts a laser, the spectrum of the light source is infrared light, the optical density detection module 220 adopts an ultra-high-speed spectrometer, the emission of the light source adopts fiber autocollimation, and the reception of the light adopts an optical fiber.

[0076] Since the purpose of the triacetin uniformity detection in the filter rod is to select unqualified products, and the optical density control value for evaluating the triacetin uniformity is for at least M segments of filter rods before the current filter rod segment to be detected, after completing the uniformity detection of the last segment of filter rod on the filter rod, the optical density control value for the uniformity detection of the next segment of filter rod needs to be adjusted. In the embodiment, the device 20 for detecting the triacetin uniformity in the filter rod online further includes an unqualified product processing module 240 connected with the signal processing module 230, and the unqualified product processing module 240 includes: an exclusion module 241 for excluding the filter rod segment with unqualified triacetin uniformity; when the exclusion module 240 excludes the filter rod segment with unqualified triacetin uniformity, the coding module 210 receives the signal sent by the signal processing module 230 and marks the filter rod segment with unqualified triacetin uniformity as a non-control sample segment.

[0077] In the embodiment, the exclusion module 241 is an exclusion valve electrically connected with the signal processing module 230, the light source is electrically connected with the optical density detection module 220, and the optical density detection module 220 is electrically connected with the signal processing module 230 to send a signal to the signal processing module 230.

[0078] During the operation of the device 20 for online detection of triacetylglycerol uniformity in filter rods, the signal processing module 230 stores the average value of the optical density of the control sample, i.e., the optical density control value. This optical density control value can be manually entered into the signal processing module 230 by the operator, or it can be the optical density processing value stored by the device after measuring the optical density of several filter rod segments. When measuring the uniformity of triacetylglycerol in a certain section of the filter rod, the light source operates and emits light to the section of the filter rod to be tested. At the same time, the light source sends the intensity of the emitted light (i.e., the incident light intensity) to the optical density detection module 220 in the form of an electrical signal. After the incident light passes through the filter rod section and is transmitted through the triacetylglycerol droplets in the filter rod section, the transmitted light is detected by the optical density detection module 220 and converted into an electrical signal. The optical density detection module 220 calculates the optical density according to the formula: optical density OD=lg(incident light intensity I0 / transmitted light intensity I) and sends the optical density signal to the signal processing module 230. The signal processing module 230 calls its stored optical density reference value and calculates the uniformity index of the current section of the filter rod to be tested according to the formula: uniformity index U=[(optical density of the current section of the filter rod to be tested - optical density reference value) / optical density reference value]x100%, and compares it with the standard value. When the uniformity index U| is ≥ 40%, the uniformity of the current filter rod segment is deemed unqualified. The signal processing module 230 controls the rejection module 241 to reject the optical density of the current filter rod segment and controls the encoding module 210 to mark the filter rod segment for subsequent rejection. If the uniformity index U| is between 15% and 40%, an alarm is triggered to alert the operator. If the uniformity index U| falls between 15% and 40% multiple times, the filter rod inspection operation can be suspended simultaneously with the alarm. In this embodiment, if the uniformity index U| falls between 15% and 40% more than three times consecutively, the filter rod inspection operation is suspended. When the uniformity index U| is < 40%, the uniformity of triacetylglycerol in the current filter rod segment is deemed qualified. The signal processing module 230 saves the optical density of the current filter rod segment and updates and saves the optical density reference value according to the optical density reference value calculation method disclosed in the aforementioned online detection method for triacetylglycerol uniformity.

[0079] It should be noted that in this embodiment, the principle for obtaining the optical density processing values ​​stored after the device first performs optical density measurements on several filter rod segments refers to the online detection method for triacetylglycerol uniformity of the present invention. That is, when it is determined to be the first detection, the signal processing module 230 collects the optical density processing values ​​of M consecutive filter rod segments on the filter rod processed by the current filter rod forming machine to obtain the optical density reference value; when it is determined to be the first detection, the optical density of all uniform qualified filter rod segments before the current filter rod segment to be tested and the optical density of M filter rod segments on the filter rod produced by the current filter rod forming machine are selected, processed, and the optical density reference value is obtained.

[0080] The device and method for detecting the uniformity of triacetin in filter rods on line according to the present application adopts the method of optical density measurement, measures the optical density of each section of the filter rod in motion in real time, and calculates the uniformity judgment value of each section of the filter rod through the conversion and frequency division processing of the signal, so that the filter rod is detected on line section by section, on the one hand, the problem of missed detection of unqualified products is avoided, so that the detection result truly reflects the actual product, on the other hand, the on-line detection of the filter rod is convenient for timely removing unqualified products, avoiding the mixing of qualified products and unqualified products, facilitating workshop management, and meeting the requirements of large-scale production of filter rods in industry.

[0081] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0082] The above-described embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as the limitation of the patent scope of the present application. It should be pointed out that, for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A device for detecting the uniformity of triacetin in a filter rod on-line, characterized in that, include: The optical density detection module (220) for online detection of formed filter rods in production, and the signal processing module (230) for processing the optical density signal provided by the optical density detection module (220), the signal processing module (230) includes an analog-to-digital converter unit for converting the optical density signal of the electrical signal into a digital signal, a data separation unit for separating the digital signal provided by the analog-to-digital converter unit into a high-frequency signal and a low-frequency signal, and a calculation unit for calculating a uniformity judgment value based on the amplitude, frequency, phase, phase shift, phase change amplitude and influence time of the high-frequency signal and the low-frequency signal; The calculation unit is also used to determine whether it is the first detection; if not, it proceeds to the normal detection process. When it is determined to be the first test, filter rods produced by the current filter rod forming machine are selected, and the optical density of M consecutive filter rod segments is measured. The optical density of the M filter rod segments is processed to obtain the initial optical density control value. When it is determined that it is not the first test, the optical density of all uniform and qualified filter rod segments before the current filter rod segment to be tested and the optical density of the M segment of filter rod produced by the current filter rod forming machine are selected, processed, and the optical density reference value is obtained. When the filter rod is tested for the first time after the equipment leaves the factory, after the equipment is turned on, the optical density of the M filter rod segments is tested first, and the initial optical density reference value is obtained by calculating the filter value or the average value. When testing the M+1 filter rod segment, the initial optical density reference value obtained from the previous M filter rod segments is used to evaluate the triacetylglycerol uniformity of the M+1 filter rod segment. When judging uniformity, compare the optical density of the current filter segment to be tested with the optical density reference value, and judge the uniformity of triacetin in the current filter segment to be tested; set the uniformity index U = [(optical density of the current filter segment to be tested - optical density reference value) / optical density reference value] x 100%. When |uniformity index U| ≥ standard value, it is judged that the triacetin spraying in the current filter segment to be tested is not uniform; when |uniformity index U| < standard value, it is judged that the triacetin spraying in the current filter segment to be tested is uniform.

2. The apparatus according to claim 1, characterized in that, It also includes an encoding module (210), which is used to select continuously produced filter rods and divide them into several continuous filter rod segments to be inspected. The optical density detection module (220) performs triacetylglycerol uniformity detection on each filter rod segment to be inspected, and the length of each filter rod segment is 0.05-150mm.

3. The apparatus according to claim 2, characterized in that, It also includes a non-conforming product processing module (240) connected to the signal processing module (230). The non-conforming product processing module includes: a rejection module for rejecting filter rod segments with non-conforming triacetylglycerol uniformity; when the rejection module rejects filter rod segments with non-conforming triacetylglycerol uniformity, the encoding module (210) receives the signal sent by the signal processing module (230) and marks the filter rod segments with non-conforming triacetylglycerol uniformity as non-control sample segments.

4. The apparatus according to claim 2, characterized in that, The optical density detection module (220) includes a light source, a coupling optical path for applying the light source to the filter rod, a converging optical path for converging the optical signal from the filter rod, and an ultra-high-speed spectrometer or optoelectronic element for performing spectral analysis on the light converged by the converging optical path.

5. The apparatus according to claim 2, characterized in that, The encoding module (210) controls the high-speed light source in the optical density detection module (220) to perform intermittent light detection on the selected moving filter rod according to the speed of the filter rod movement. Two adjacent light detections divide the filter rod into multiple continuous filter rod segments to be inspected, and the length of each filter rod segment to be inspected is 0.05-150mm.

6. A method for online detection of the uniformity of triacetin in a filter rod, characterized in that, The device for online detection of triacetylglycerol uniformity in filter rods as described in any one of claims 1-5 shall be used. Includes the following steps: S1: The optical density signal of the finished filter rod segment in motion is obtained by the optical density detection module (220); S2: Converts optical density electrical signals into digital signals; S3: Separate the digital signal into high-frequency and low-frequency signals; S4: Compare the amplitude, frequency, phase, and phase shift of high- and low-frequency signals; S5: Based on the amplitude of the change and the duration of the effect, obtain the uniformity judgment value of triacetylglycerol in the filter rod; During the optical density testing of the filter rod, it is also necessary to set optical density control values ​​for calculating the triacetylglycerol uniformity judgment value of the filter rod, including: The optical density passing through the current filter rod segment to be tested is detected, and it is determined whether this is the first test. If not, the normal testing process is initiated. When it is determined to be the first test, filter rods produced by the current filter rod forming machine are selected, and the optical density of M consecutive filter rod segments is measured. The optical density of the M filter rod segments is processed to obtain the initial optical density control value. When it is determined that it is not the first test, the optical density of all uniform and qualified filter rod segments before the current filter rod segment to be tested and the optical density of the M segment of filter rod produced by the current filter rod forming machine are selected, processed, and the optical density reference value is obtained. When the filter rod is tested for the first time after the equipment leaves the factory, after the equipment is turned on, the optical density of the M filter rod segments is tested first, and the initial optical density reference value is obtained by calculating the filter value or the average value. When testing the M+1 filter rod segment, the initial optical density reference value obtained from the previous M filter rod segments is used to evaluate the triacetylglycerol uniformity of the M+1 filter rod segment. When judging uniformity, compare the optical density of the current filter segment to be tested with the optical density reference value, and judge the uniformity of triacetin in the current filter segment to be tested; set the uniformity index U = [(optical density of the current filter segment to be tested - optical density reference value) / optical density reference value] x 100%. When |uniformity index U| ≥ standard value, it is judged that the triacetin spraying in the current filter segment to be tested is not uniform; when |uniformity index U| < standard value, it is judged that the triacetin spraying in the current filter segment to be tested is uniform.

7. The method according to claim 6, characterized in that, In step S3, signals with frequencies higher than the predetermined reference frequency are separated into high-frequency signals by wavelet transform or mean method, while the rest are low-frequency signals.

8. The method according to claim 7, characterized in that, The reference frequency is 800Hz.

9. The method according to claim 6, characterized in that, The steps preceding step S1 also include: T1) The plasticizer is sprayed onto the filament bundle moving at high speed; T2) The sprayed filament bundles are concentrated and narrowed and wrapped with filter rod forming paper; T3) The filter rod is shaped by the upper and lower smoke guns. Step S1 tests the plasticizer uniformity of the filter rod after it is shaped by the upper and lower smoke guns. Alternatively, the steps before step S1 may include: T1) The plasticizer is sprayed onto the filament bundle moving at high speed; T2) The sprayed filament bundles are concentrated and narrowed to form paperless filter rods; T3) Step S1: Perform plasticizer uniformity test on the paperless filter rod.

10. The method according to claim 6, characterized in that, Step S5 also includes: removing filter rod segments that do not meet the uniformity requirements and marking them as non-control sample segments.

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