Quantitative evaluation method for internal pressure drop stability of filter stick

Abstract

The invention discloses a quantitative evaluation method for the internal pressure drop stability of a filter stick, which comprises the following steps of: 1, acquiring batch detection data of weight, circumference and length of a single filter stick of a certain mark, and theoretically calculating the average density of the single filter stick; 2, sorting is conducted according to the average density of the filter sticks, physical indexes of the sorted filter sticks are obtained, sorted data are grouped, and the density and the pressure drop average value of each group of filter sticks are taken at intervals; 3, constructing a filter stick density-pressure drop correlation mathematical model; 4, detecting the density of the filter stick by adopting a microwave moisture density measuring instrument, and theoretically calculating the range of the average density of each section of the filter stick according to the actual slitting times of the filter stick; and 5, quantitatively evaluating the stability of the internal pressure drop of the filter stick by using the filter stick density-pressure drop related mathematical model. The method provides theoretical support for evaluating the pressure drop stability of the cut filter stick, and has important guiding significance for controlling the production process of the filter stick and stably improving the quality of cigarettes.

Description

Technical Field

[0001] The invention relates to a stability evaluation of the quality of cigarette auxiliary materials during processing, and in particular to a quantitative evaluation method for the stability of the internal pressure drop of a filter rod. Background Art

[0002] As an important part of cigarettes, the stability of filter rod pressure drop has a great influence on the draw resistance of cigarettes. Improving the stability of filter rod pressure drop can effectively control the fluctuation of cigarette draw resistance index and achieve the purpose of improving the homogenization level of cigarettes. In the actual production process of filter rods, the pressure drop is affected by many factors such as the opening roller ratio, the pre-tension roller pressure, the high-pressure nozzle, the production speed and the air opening plate. At the same time, combined with the actual production process of cigarettes, the filter rod is cut into double-length filter tips by the cutting wheel, and the cut filter tips are then sent to the offset wheel, and then the offset filter tips are sucked to the center of the drum wheel in a single row by the unifying wheel through negative pressure, and the double-length filter tips are sent to the transition wheel between the two cigarettes by the acceleration wheel, and then the double-length filter tips are cut into two filter tips of equal length by secondary cutting.

[0003] At present, most cigarette companies generally conduct pressure drop tests on 30 filter rods taken out during delivery inspection according to the requirements of "Acetate Filter Rods for Tobacco and Tobacco Products (GB / T5605-2002), and mainly determine the stability of the filter rod pressure drop by calculating the SD of the pressure drop of the 30 filter rods. However, the whole filter rod is cut several times before being connected to the cigarette, and finally forms 4 or 6 cigarettes. The uneven density distribution of the filter rod is bound to affect the stability of the draw resistance of a single cigarette. It is somewhat one-sided to only evaluate the stability of the pressure drop between filter rods.

[0004] Domestic cigarette manufacturers have begun to use the microwave method to detect filter rod density and use the numerical difference in filter rod density to evaluate the quality stability of filter rods. However, there are few reports on the use of density values ​​to convert them into pressure drops to evaluate the quality stability of filter rods. The Chinese invention patent publication number CN107084995A, published on 2017-08-22, provides a method for evaluating the uniformity of cigarette density distribution, but the provided method is not suitable for filter rods. The Chinese invention patent publication number CN112394006A, published on 2021.02.23, provides a filter rod stability evaluation method based on the filter rod cutting characteristics and the average density range of each section of the filter rod, but the provided method cannot effectively link the density range with the pressure drop stability, and the evaluation has a certain degree of independence. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a quantitative evaluation method for the internal pressure drop stability of a filter rod, so as to quantitatively evaluate the internal pressure drop stability of a filter rod with filter rod cutting characteristics, provide theoretical support for the evaluation of the pressure drop stability of the filter rod after cutting, and thus have important guiding significance for the cigarette production process control and filter rod molding design.

[0006] In order to achieve the purpose, the present invention adopts the following technical scheme:

[0007] The quantitative evaluation method of the internal pressure drop stability of a filter rod of the present invention is characterized in that it comprises the following steps:

[0008] Step 1: Select m groups of filter rods of a certain brand, each group containing n filter rods, collect the physical indicators of each filter rod in each group, including weight, circumference, length, and pressure drop, and then use formula (1) to calculate the average density ρ of the jth filter rod in the i-th group: ij :

[0009] ρ ij =M ij 4πΔ / L ij (C ij ) 2 (1)

[0010] In formula (1): M ij represents the weight of the jth filter rod in the i-th group; π represents the circumference of a circle; Δ represents the unit conversion value; L ij represents the length of the jth filter rod in the i-th group; C ij represents the circumference of the j-th filter rod in the i-th group; i∈[1,m], j∈[1,n];

[0011] Step 2, sorting the physical index of each filter rod in the m group according to its average density, and obtaining the physical index data of the sorted m×n filter rods;

[0012] Step 3: Taking h as the total number of filter rods in each group, the physical index data of the sorted m×n filter rods are divided into t=m×n / h groups of filter rods according to the total number of filter rods h, and then the average density ρ of the filter rods in the ath group is calculated using formula (2) and formula (3) respectively. a , average pressure drop P a :

[0013]

[0014] In formula (2) and formula (3), ρ' a,u represents the average density of the uth filter rod in the ath group of filter rods after sorting; p a,u It represents the average pressure drop of the uth filter rod in the ath group of filter rods after sorting;

[0015] Step 4, fitting a linear model of filter rod pressure drop-average density according to the linear relationship between the average density and pressure drop of t groups of filter rods;

[0016] Step 5, using formula (4) to calculate the density calibration coefficient k1 of the microwave moisture density detector, which is used to perform density calibration on the microwave moisture density detector;

[0017]

[0018] In formula (4), m1 represents the actual weight of any single filter rod of the brand after removing the wrapping paper; m2 represents the weight of the filter rod of the brand measured by the microwave moisture density detector;

[0019] Step 6, using formula (5) to calculate the moisture deviation value k2 of the microwave moisture density detector, which is used to calibrate the moisture of the microwave moisture density detector;

[0020] k2=m4-m3 (5)

[0021] In formula (5), m3 represents the average moisture value of the filter rod of the brand measured by the microwave moisture density detector, and m4 represents the average moisture value of the filter rod of the brand measured by the standard laboratory method;

[0022] Step 7: Perform microwave density detection on D filter rods of the brand using a microwave moisture density detector calibrated with density and moisture to obtain the original density detection result of each filter rod, wherein the original density detection result of the dth filter rod is recorded as X. d ={X d1 ,X d2 ,…,X dv ,…,X dV}, where X dv represents the density value of the d-th filter rod at the v-th detection point; V represents the total number of detection points;

[0023] Step 8: With E as the total number of detection points per section of a single filter rod, the dth filter rod of the brand is divided into R sections according to the total number of detection points E, and the average density of the rth section of the dth filter rod is calculated using formula (6): Thus, the average density of the R section of the dth filter rod is obtained.

[0024]

[0025] In formula (6): X dre represents the density value at the e-th detection point of the r-th section of the d-th filter rod; L represents the length of a single filter rod of the brand;

[0026] Step 9: Based on the average density of the R segment of the d-th filter rod, use formula (7) to calculate the average density of the r-th segment of the D-th filter rod: Thus, the average density of the R section of D filter rods is obtained.

[0027]

[0028] Step 10: Calculate the average density range of D filter rods using formula (8):

[0029]

[0030] In formula (8), Max means taking the maximum value, and Min means taking the minimum value;

[0031] Step 11: Average density range Substitute it into the linear model of pressure drop-average density to calculate the pressure drop range of D filter rods Then the stability of pressure drop in the filter rod production process is quantitatively evaluated.

[0032] An electronic device of the present invention includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the quantitative evaluation method, and the processor is configured to execute the program stored in the memory.

[0033] The present invention provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and the computer program executes the steps of the quantitative evaluation method when the computer program is executed by a processor.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. Based on the principle that the average density and pressure drop of the same brand of filter rods are linearly correlated, the present invention selects batch physical inspection data of any brand of filter rods, and constructs a mathematical model of the average density-pressure drop of the brand of filter rods through big data analysis. This model is used to quantitatively evaluate the influence of filter rod density on pressure drop, and has certain feasibility.

[0036] 2. The present invention combines the cutting characteristics of filter rods of different brands, uses the microwave moisture density detector MW 3220 to calculate the average density of each section of the filter rod after cutting, and then calculates the average density range of each section of the filter rod, which is converted into the pressure drop range through the application of relevant mathematical models, and then quantitatively evaluates the internal pressure drop stability of the filter rod, which has important guiding significance for the control of the filter rod forming process and process analysis, and has certain innovation.

[0037] 3. The present invention is applicable to the quantitative evaluation of the internal pressure drop stability of filter rods of different specifications and types based on the analysis of test data from a comprehensive test bench and a microwave density detector, and has certain applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a flow chart of the method of the present invention;

[0039] Figure 2 This is a linear model diagram of the filter rod suction resistance-pressure drop of the present invention. DETAILED DESCRIPTION

[0040] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0041] Example 1

[0042] In this embodiment, a quantitative evaluation method for the stability of the internal pressure drop of a filter rod is provided, which is based on the batch test data of the physical indicators of a single filter rod of any brand, and the correlation analysis between the average density and the pressure drop of the filter rod is performed, and then a relevant mathematical model is constructed. Combined with the cutting characteristics of the filter rod, the average density difference of each section of the filter rod after cutting is theoretically calculated, and the mathematical model of the average pressure drop-density of the filter rod is applied to quantitatively evaluate the production process of the filter rod and the stability of the internal pressure drop after balancing.

[0043] Specifically, Figure 1 As shown, the method comprises the following steps:

[0044] Step 1: Obtain information of m groups of filter rods of a certain brand (each group contains n filter rods), collect the physical indicators of each filter rod in each group, including weight, circumference, length, and pressure drop, and then use formula (1) to calculate the average density ρ of the jth filter rod in the i-th group: ij ,In the specific implementation, some abnormal data detected by the ,physical indicators of the filter rod of the comprehensive test bench are ,eliminated.

[0045] ρ ij =M ij 4πΔ / L ij (C ij ) 2 (1)

[0046] In formula (1): M ij represents the weight of the jth filter rod in the i-th group; π represents the circumference of a circle; Δ represents the unit conversion value; L ij represents the length of the jth filter rod in the i-th group; C ij Represents the circumference of the j-th filter rod in the i-th group; i∈[1,m], j∈[1,n].

[0047] Step 2: sort the physical index of each filter rod in the m groups according to its average density to obtain the sorted physical index data of m×n filter rods; in the specific implementation, the pressure drop data of a single filter rod is sorted synchronously with the density data.

[0048] Step 3: further, taking h as the total number of filter rods in each group, the physical index data of the sorted m×n filter rods are divided into t=m×n / h groups of filter rods according to the total number of filter rods h, and then the average density ρ of the filter rods in the ath group is calculated using formula (2) and formula (3) respectively. a , average pressure drop P a In the specific implementation, the minimum unit h needs to be set according to the total sample size m groups × n branches, which should be divisible by the total sample number and should not be too large or too small.

[0049]

[0050] In formula (2) and formula (3), ρ' a,u represents the average density of the uth filter rod in the ath group of filter rods after sorting; p a,u It represents the average pressure drop of the u-th filter rod in the a-th group of filter rods after sorting.

[0051] Step 4: Figure 2 As shown, according to the linear relationship between the average density and the average pressure drop of the filter rods in group t, a linear model of filter rod pressure drop-average density is fitted; in the specific implementation, the linear correlation of the filter rod pressure drop-average density model needs to be further evaluated.

[0052] Step 5, using formula (4) to calculate the density calibration coefficient k1 of the microwave moisture density detector, which is used to perform density calibration on the microwave moisture density detector;

[0053]

[0054] In formula (4), m1 represents the actual weight of any single filter rod of the brand after removing the molding paper; m2 represents the weight of the filter rod of the brand measured by the microwave moisture density detector.

[0055] Step 6, using formula (5) to calculate the moisture deviation value k2 of the microwave moisture density detector, which is used to calibrate the moisture of the microwave moisture density detector;

[0056] k2=m4-m3 (5)

[0057] In formula (5), m3 represents the average moisture value of the filter rod of the brand measured by the microwave moisture density detector, and m4 represents the average moisture value of the filter rod of the brand measured by the standard laboratory method.

[0058] Step 7: Perform microwave density detection on D filter rods of the brand using a microwave moisture density detector calibrated with density and moisture to obtain the original density detection result of each filter rod, wherein the original density detection result of the dth filter rod is recorded as X. d ={X d1 ,X d2 ,…,X dv ,…,X dV}, X dv represents the density value of the d-th filter rod at the v-th detection point; V represents the total number of detection points; in specific implementation, different parameters of the microwave density detector MW 3220 are set and adjusted according to the specifications (length, circumference) of the detection filter rod.

[0059] Step 8: With E as the total number of detection points per section of a single filter rod, the dth filter rod of the brand is divided into R sections according to the total number of detection points E, and the average density of the rth section of the dth filter rod is calculated using formula (6): Thus, the average density of the R section of the dth filter rod is obtained. In the specific implementation, the distorted density data at both ends of the filter rod are removed, the density mean calculation is not performed for the data within 5 mm of the starting and ending sections, and the filter rod is segmented according to the length of the filter rod and the actual cutting characteristics.

[0060]

[0061] In formula (6): X dre It represents the density value at the e-th detection point of the r-th section of the d-th filter rod; L represents the length of a single filter rod of the brand.

[0062] Step 9: Based on the average density of the R segment of the d-th filter rod, use formula (7) to calculate the average density of the r-th segment of the D-th filter rod: Thus, the average density of the R section of D filter rods is obtained. In a specific implementation, the average density of each section of a single filter rod is calculated first, and then the average value of the average density of each section of the filter rod is calculated according to the actual number of filter rods tested.

[0063]

[0064] Step 10: Calculate the average density range of D filter rods using formula (8):

[0065]

[0066] In formula (8), Max means taking the maximum value, and Min means taking the minimum value.

[0067] Step 11: Average density range Substitute it into the linear model of pressure drop-average density to calculate the pressure drop range of D filter rods Then the stability of the pressure drop during the production process of the D filter rods was evaluated. In the specific implementation, the stability of the pressure drop inside the filter rod was quantitatively evaluated according to the pressure drop difference of the segmented filter rods. The smaller the pressure drop range of each segment, the more stable the pressure drop inside the filter rod.

[0068] In this embodiment, an electronic device includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the above method, and the processor is configured to execute the program stored in the memory.

[0069] In this embodiment, a computer-readable storage medium stores a computer program on the computer-readable storage medium, and the computer program executes the steps of the above method when executed by a processor.

[0070] Example 2

[0071] This embodiment continues to disclose the following contents based on the embodiment 1. In theory, it is necessary to obtain the physical index test data of the filter rod batch to establish the pressure drop-density related mathematical model to improve the accuracy and reliability of the model prediction. Considering the large amount of original data, it is not convenient to fully display it in the content. For the sake of understanding, this case takes the original physical index test data of a group of 30 filter rods as an example:

[0072] Step 1: The technical standard of brand A high-transmittance acetate filter rod is "120mm×24.2mm×3150Pa×15000cu". The physical indicators of 30 filter rods are collected, including weight, circumference, length, and pressure drop, and the average density ρ of each filter rod is calculated using formula (1): j , see Table 1 for details:

[0073] ρ j =M j 4πΔ / L j (C j ) 2 (1)

[0074] In formula (1): M j represents the weight of the jth filter rod; π represents the ratio of circumference to circumference; Δ represents the unit conversion value; L j represents the length of the jth filter rod; C j Represents the circumference of the j-th filter rod; j∈[1,30].

[0075] Table 1 Calculation results of filter rod average density

[0076]

[0077]

[0078] Step 2: Sort the physical indexes of the 30 filter rods according to their average density to obtain the physical index data of the 30 sorted filter rods, as shown in Table 2.

[0079] Table 2 Physical indicators of filter rods sorted by density

[0080]

[0081]

[0082] Step 3: Further, the physical index data of the 30 filter rods after sorting are divided into 6 groups with 5 as the total number of filter rods in each group, and the average density ρ of each group of filter rods is calculated using formula (2) and formula (3) respectively. a , average pressure drop P a , see Table 3 for details.

[0083]

[0084] In formula (2) and formula (3), ρ' a,u represents the average density of the uth filter rod in the ath group of filter rods after sorting; p a,u It represents the average pressure drop of the u-th filter rod in the a-th group of filter rods after sorting.

[0085] Table 3 Filter rod density and suction resistance data after grouping

[0086] Grouping <![CDATA[Density (mg / cm 3 )]]> Absorption resistance(Pa) Group 1 161.26 3069.4 Group 2 162.52 3154.2 Group 3 163.32 3183.6 Group 4 163.78 3187.2 Group 5 164.76 3247.0 Group 6 166.47 3331.8

[0087] Step 4: According to the relationship between the average density and average pressure drop of the above six groups of filter rods, a linear model of filter rod pressure drop-average density is fitted. The regression coefficient of the model is R 2 >0.98, goodness of fit, see Figure 1 .

[0088] Step 5: Calculate the density calibration coefficient k1 of the microwave moisture density detector using formula (4) for density calibration of the microwave moisture density detector. Where m1 is 0.910 g, m2 is 0.920 g, and k1 is 0.989.

[0089]

[0090] In formula (4), m1 represents the actual weight of any single filter rod of the brand after removing the molding paper; m2 represents the weight of the filter rod of the brand measured by the microwave moisture density detector.

[0091] Step 6: Calculate the moisture deviation value k2 of the microwave moisture density detector using formula (5) for moisture calibration of the microwave moisture density detector. Wherein, m4 is 7.9%, m3 is 7.1%, and k2 is 0.8%.

[0092] k2=m4-m3 (5)

[0093] In formula (5), m3 represents the average moisture value of the filter rod of the brand measured by the microwave moisture density detector, and m4 represents the average moisture value of the filter rod of the brand measured by the standard laboratory method.

[0094] Step 7: Random sampling is performed during the filter rod production process. A microwave moisture density detector calibrated for density and moisture is used to perform microwave density detection on 30 filter rods of brand A to obtain the original density detection result of each filter rod. The detection interval is 1 mm, the detection length is set to 120 mm, and the detection diameter is set to 7.12 mm.

[0095] Step 8: Since the length of the brand A filter rod is 120 mm, it is used in 1-for-4 ways in the actual production process. The total number of detection points of each section of a single filter rod is 30. The d-th filter rod of the brand is divided into 4 sections according to the total number of detection points. The average density of the r-th section of the d-th filter rod is calculated using formula (6). Thus, the average density of each section of the dth filter rod is obtained.

[0096]

[0097] Step 9: Based on the average density of each segment of the dth filter rod, use formula (7) to calculate the average density of the rth segment of 30 filter rods: Thus, the average density of each section of 30 filter rods is obtained, and the range of the average density of each section after the filter rod is cut is calculated. See Table 4 for details.

[0098] Table 4 Average density test results of each section of filter rod

[0099]

[0100]

[0101] Step 10: From Table 4, it can be seen that the average density range of each section of the filter rod is 1.2 mg / cm 3 The average value of the average density range of each section is 0.63 mg / cm 3 According to the filter rod pressure drop-average density linear model, the theoretical calculation shows that the pressure drop range of each section of the filter rod is 58Pa and the mean value of the range is 31Pa. The internal pressure drop stability of this brand of filter rod is generally good.

[0102] The above description is only an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A quantitative evaluation method for the stability of the internal pressure drop of a filter rod, characterized in that: The steps include: Step 1: Select m groups of filter rods of a certain brand, each group containing n filter rods, collect the physical indicators of each filter rod in each group, including weight, circumference, length, and pressure drop, and then use formula (1) to calculate the average density ρ of the jth filter rod in the i-th group: ij : r ij =M ij 4pD / L ij (C ij ) 2 (1) In formula (1): M ij represents the weight of the jth filter rod in the i-th group; π represents the circumference of a circle; Δ represents the unit conversion value; L ij represents the length of the jth filter rod in the i-th group; C ij represents the circumference of the j-th filter rod in the i-th group; i∈[1,m], j∈[1,n]; Step 2, sorting the physical index of each filter rod in the m group according to its average density, and obtaining the physical index data of the sorted m×n filter rods; Step 3: Taking h as the total number of filter rods in each group, the physical index data of the sorted m×n filter rods are divided into t=m×n / h groups of filter rods according to the total number of filter rods h, and then the average density ρ of the filter rods in the ath group is calculated using formula (2) and formula (3) respectively. a , average pressure drop P a : In formula (2) and formula (3), ρ' a,u represents the average density of the uth filter rod in the ath group of filter rods after sorting; p a,u It represents the average pressure drop of the uth filter rod in the ath group of filter rods after sorting; Step 4, fitting a linear model of filter rod pressure drop-average density according to the linear relationship between the average density and pressure drop of t groups of filter rods; Step 5, using formula (4) to calculate the density calibration coefficient k1 of the microwave moisture density detector, which is used to perform density calibration on the microwave moisture density detector; In formula (4), m1 represents the actual weight of any single filter rod of the brand after removing the wrapping paper; m2 represents the weight of the filter rod of the brand measured by the microwave moisture density detector; Step 6, using formula (5) to calculate the moisture deviation value k2 of the microwave moisture density detector, which is used to calibrate the moisture of the microwave moisture density detector; k2=m4-m3 (5) In formula (5), m3 represents the average moisture value of the filter rod of the brand measured by the microwave moisture density detector, and m4 represents the average moisture value of the filter rod of the brand measured by the standard laboratory method; Step 7: Perform microwave density detection on D filter rods of the brand using a microwave moisture density detector calibrated with density and moisture to obtain the original density detection result of each filter rod, wherein the original density detection result of the dth filter rod is recorded as X. d ={X d1 ,X d2 ,…,X dv ,…,X dV }, where X dv represents the density value of the d-th filter rod at the v-th detection point; V represents the total number of detection points; Step 8: With E as the total number of detection points per section of a single filter rod, the dth filter rod of the brand is divided into R sections according to the total number of detection points E, and the average density of the rth section of the dth filter rod is calculated using formula (6): Thus, the average density of the R section of the dth filter rod is obtained. In formula (6): X dre represents the density value at the e-th detection point of the r-th section of the d-th filter rod; L represents the length of a single filter rod of the brand; Step 9: Based on the average density of the R segment of the d-th filter rod, use formula (7) to calculate the average density of the r-th segment of the D-th filter rod: Thus, the average density of the R section of D filter rods is obtained. Step 10: Calculate the average density range of D filter rods using formula (8): In formula (8), Max means taking the maximum value, and Min means taking the minimum value; Step 11: Average density range Substitute it into the linear model of pressure drop-average density to calculate the pressure drop range of D filter rods Then the stability of pressure drop in the filter rod production process is quantitatively evaluated.

2. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store a program that supports the processor to execute the quantitative evaluation method according to claim 1, and the processor is configured to execute the program stored in the memory.

3. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the quantitative evaluation method according to claim 1 are executed.

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