A stem compression quality evaluation method

Abstract

The present application relates to a kind of stem pressing quality evaluation methods, first take the tobacco stem of different sizes before stem pressing, rotate tobacco stem and measure tobacco stem diameter at node, calculate the width and thickness of tobacco stem before stem pressing;Then collect the front and cross-sectional photographs of tobacco stem after stem pressing, calculate the average width and thickness of tobacco stem after stem pressing after image processing;Further obtain the original size ratio of tobacco stem before stem pressing and the deformation size ratio of tobacco stem after stem pressing, further calculate to obtain the deformation characteristic index of stem pressing in different diameter interval and total stem pressing deformation characteristic index, compared with the standard value of stem pressing deformation characteristic index under corresponding parameters, obtain the stem pressing quality characterization evaluation coefficient, to quantitatively characterize the stem pressing quality in different diameter interval and overall stem pressing quality, provide technical guidance for stem pressing process parameter optimization.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of tobacco stem processing, and particularly relates to a method for evaluating the quality of pressed stems. BACKGROUND

[0002] Tobacco stem is one of important raw materials for cigarette processing. Well-processed stem can improve the filling capacity of finished cigarette, improve the burning property of cigarette, reduce the amount of tar, and further stabilize the sensory quality. Stem cutting is a key process for stem processing, and stem pressing is required before stem cutting. If the quality of pressed stems is poor, the forming effect of cut stems after cutting is poor, the filling property and whole stem rate are low, the breakage is further increased, and the quality of cut stems cannot meet the process requirements. Pressed stem refers to tobacco stem after being pressed by a stem press. The quality of pressed stems is mainly reflected by the deformation degree of pressed stems, which is mainly affected by the thickness of pressed stems, the uniformity of stress of tobacco stems during pressing, and the moisture and temperature of tobacco stems before pressing.

[0003] At present, cigarette manufacturers mainly measure the thickness of pressed stems, and indirectly reflect the quality of pressed stems by counting the deviation of the thickness of pressed stems or comparing the difference between the measured value and the standard value. For example, a method for detecting the thickness of pressed stems is disclosed in patent CN201010602313.6, which reflects the processing quality of the stem press and further evaluates the quality of tobacco stems. However, the method for evaluating the quality of pressed stems by the thickness of pressed stems does not consider the change of the width of tobacco stems in addition to the change of the thickness of tobacco stems during pressing. The method for evaluating the quality of pressed stems by the thickness of pressed stems is one-sided, and the thickness of pressed stems at different measuring points is inconsistent, and the measurement result also has a large deviation. Obviously, the method cannot objectively reflect the actual situation of pressed stems.

[0004] Therefore, it is of great significance to develop a method for accurately evaluating the quality of pressed stems. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, the present application aims to provide a method for evaluating the quality of pressed stems. The method calculates the deformation characteristic index of pressed stems after pressing, reflects the deformation characteristics of the size of tobacco stems after pressing by using the deformation characteristic index of pressed stems, and obtains a quality characterization evaluation coefficient of pressed stems by comparing with the standard reference value of the deformation characteristic index, and then quantitatively evaluates the quality of pressed stems.

[0006] Since tobacco stems are often circular, oval, or flat in cross-section, during the actual stem compression process, as the stem thickness changes longitudinally, the width of the compressed stems also changes laterally. Furthermore, the thinner the original stems, the thinner the thickness of the compressed stems, while the wider the original stems, the wider the width of the compressed stems. Consequently, both the width and thickness of the tobacco stems undergo significant deformation at the moment of compression. Therefore, the inventors of this application realized that both stem width and thickness are the most direct deformation characteristic parameters during the stem compression process, and that using only stem thickness to evaluate compressed stem quality is one-sided. This led to the creation of the present invention.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for evaluating stem compression quality comprises the following steps:

[0009] (1) taking tobacco stems of different sizes and dividing the tobacco stems into multiple diameter intervals according to their diameters;

[0010] (2) Count the tobacco stem contents in different diameter ranges;

[0011] (3) obtaining the width and thickness of the tobacco stems before stem compression;

[0012] (4) obtaining the width and thickness of the tobacco stems after the tobacco stems are compressed;

[0013] (5) Calculate the original stem size ratio K before stem compression in different diameter intervals according to the following formula r0 and the ratio of tobacco stem deformation size after stem compression K r1 ;

[0014]

[0015] Where W0 is the width of the tobacco stem before pressing, T0 is the thickness of the tobacco stem before pressing, W1 is the width of the tobacco stem after pressing, T1 is the thickness of the tobacco stem after pressing, m is the number of tobacco stems in different diameter ranges, and r is the diameter range;

[0016] (6) According to the original size ratio of the tobacco stem before pressing and the deformation size ratio of the tobacco stem after pressing, the deformation characteristic index K of the pressed stem in different diameter ranges is calculated. r , and then according to the tobacco stem content in different diameter intervals, the total stem deformation characteristic index K is obtained; wherein the stem deformation characteristic index K r It is used to characterize the compression quality of the stem in different diameter ranges, and the total compression deformation characteristic index K is used to characterize the overall compression quality; K r and K are calculated using the following formulas:

[0017]

[0018]

[0019] K = (S - S ) / S r1 is the size ratio of the compressed tobacco stem, K r0 is the size ratio of the original tobacco stem, P r is the content of tobacco stem in different diameter intervals, n is the number of diameter intervals;

[0020] (7) The total compression deformation characteristic index of the tobacco stem meeting the process standard is taken as the standard reference value K 标 of the total compression deformation characteristic index of the tobacco stem, and the compression quality characterization evaluation coefficient k is calculated according to the ratio of the total compression deformation characteristic index of the tobacco stem to the standard reference value K 标 .

[0021] As a preferred embodiment of the present application, the number of tobacco stems in step (1) is greater than or equal to 100, the diameter of the tobacco stem is greater than or equal to 2.5 mm, and the length of the tobacco stem is greater than or equal to 10.0 mm.

[0022] As a preferred embodiment of the present application, the method for obtaining the width and thickness of the tobacco stem before compression in step (3) is as follows: the tobacco stem is divided into multiple nodes along the length direction of the tobacco stem, and the diameters of the tobacco stem corresponding to each node are measured multiple times, the average of the maximum values of the diameters of the measured nodes is taken as the width of the tobacco stem before compression, and the average of the minimum values of the diameters of the measured nodes is taken as the thickness of the tobacco stem before compression.

[0023] The selection position of the node is not limited, and as a preferred embodiment of the present application, the node is at 1 / 4, 1 / 2 or 3 / 4 of the length direction of the tobacco stem, so as to avoid inaccurate results caused by concentrated measurement in a local area.

[0024] As a preferred embodiment of the present application, the diameters of the tobacco stem corresponding to each node are measured by rotating the tobacco stem for one revolution, so as to ensure the accuracy of the measurement results.

[0025] As a preferred embodiment of the present application, the method for obtaining the width and thickness of the tobacco stem after compression in step (4) is as follows:

[0026] S1. The tobacco stem is compressed, and the front view and cross-sectional view of the tobacco stem after compression are obtained;

[0027] S2. The image of the tobacco stem after compression is processed to obtain the front area S 正面 and the cross-sectional area S 截面 of the tobacco stem after compression;

[0028] S3. The length L of the tobacco stem after compression is measured, and the width and thickness of the tobacco stem after compression are calculated according to the following formula:

[0029] W1=S 正面 / L;T1=S 截面 / W1

[0030] In the formula, W1 is the width of the pressed tobacco stem, S 正面 is the front area of the pressed tobacco stem, L is the length of the pressed tobacco stem; T1 is the thickness of the pressed tobacco stem, S 截面 is the cross-sectional area of the pressed tobacco stem.

[0031] The moisture and temperature of the tobacco stem raw material before pressing affect the pressing quality, in order to further ensure the accuracy of the evaluation results, as a preferred embodiment of the present application, S1 washes and moisturizes the tobacco stem before pressing to ensure that the moisture content of the tobacco stem before pressing is 26-30% and the temperature is 30±2℃.

[0032] As a preferred embodiment of the present application, when S1 presses the tobacco stem, the gap between the pressing rollers of the pressing machine used is (0.9-1.2)±0.1 mm, so as to ensure that the standard reference value of the deformation characteristic index of the pressed tobacco stem under different pressing parameters can be obtained, thereby providing a standard reference basis for selecting appropriate pressing processing parameters for tobacco stems of different sizes.

[0033] As a preferred embodiment of the present application, the image processing of S2 includes tobacco stem contour extraction, threshold processing, pixel extraction, and pixel and geometric value data conversion, and the processing software can be Matlab, Image-J, Photoshop, etc.

[0034] As a preferred embodiment of the present application, the method for measuring the length of the pressed tobacco stem in S3 is as follows: the pressed tobacco stem is divided into multiple nodes along the width direction of the pressed tobacco stem, the length of the tobacco stem at each node is measured multiple times, and the average value is taken as the length of the pressed tobacco stem.

[0035] The present application first takes tobacco stems of different sizes before pressing, rotates the tobacco stems and measures the diameter of the tobacco stems at nodes, calculates the average width and thickness of the tobacco stems before pressing, then collects the front and cross-sectional photos of the pressed tobacco stems, processes the images and calculates the average width and thickness of the pressed tobacco stems, further obtains the original size ratio of the tobacco stems before pressing and the deformation size ratio of the pressed tobacco stems, further calculates the deformation characteristic index of the pressed tobacco stems in different diameter intervals and the total deformation characteristic index of the pressed tobacco stems, and compares the deformation characteristic index of the pressed tobacco stems under the corresponding parameters with the standard value of the deformation characteristic index under the corresponding parameters, so as to obtain the evaluation coefficient of the quality of the pressed tobacco stems, thereby quantitatively characterizing the pressing quality of different diameter intervals and the overall pressing quality, and providing technical guidance for the optimization of pressing process parameters.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] (1) The application provides a tobacco stem crushing quality evaluation method, which is easy to understand, simple to operate, convenient to calculate, accurate and reliable in measurement results.

[0038] (2) The tobacco stem crushing deformation characteristic index defined in the application can reflect the change amount of the size deformation characteristic of the tobacco stem after crushing, and the tobacco stem crushing quality characterization evaluation coefficient is obtained by comparing the tobacco stem crushing deformation characteristic index under the corresponding parameters with the standard value of the tobacco stem crushing deformation characteristic index, so as to quantitatively characterize and evaluate the tobacco stem crushing quality and objectively reflect the real situation of the deformation quality before and after crushing.

[0039] (3) According to the tobacco stem crushing deformation characteristic index, the standard reference value of the tobacco stem crushing deformation characteristic index of tobacco stems of different sizes under different tobacco stem crushing parameters can be established, which not only characterizes and evaluates the tobacco stem crushing quality, but also provides technical guidance for optimizing the tobacco stem crushing process parameters and controlling the production process. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 It is a flowchart of a tobacco stem crushing quality evaluation method.

[0041] Figure 2 It is a schematic diagram of a measurement point.

[0042] Figure 3 It is a comparison diagram of the appearance deformation of the tobacco stem before and after crushing in the second batch of tobacco stems in Example 1.

[0043] Figure 4 It is a schematic diagram of the tobacco stem after crushing in the second batch of tobacco stems in Example 1 before and after image processing.

[0044] Figure 5 It is a diagram of the change of the tobacco stem crushing quality characterization evaluation coefficient with the production batch in Example 1.

[0045] Figure 6 It is a comparison diagram of the appearance deformation of the tobacco stem before and after crushing when the crushing roller parameter is 1.0±0.1 mm in Example 2. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the application more clear and understandable, the application will be further described in detail below with reference to the examples. It should be understood that the specific examples described herein are only used to explain the application and do not limit the application.

[0047] Example 1

[0048] A tobacco stem crushing quality evaluation method, comprising the following steps:

[0049] (1) Randomly select tobacco stems with diameter ≥2.5mm and length ≥10.0mm from a production line of Hubei Zhongyan Cigarette Factory for five times, and take 100 stems each time. Then, according to the diameter of the tobacco stems, use a vibration sorting sieve to divide the tobacco stems into five diameter intervals, i.e. 2.5-3.5mm, 3.5-4.5mm, 4.5-5.5mm, 5.5-6.5mm, and >6.5mm;

[0050] (2) Calculate the content P of tobacco stems in different diameter intervals (i.e. the percentage of the number of tobacco stems in different diameter intervals in the total number of tobacco stems), and mark them; r

[0051] (3) Take 1 / 4, 1 / 2, and 3 / 4 of the length of the tobacco stem as the measurement nodes (as shown in Figure 2 ), rotate the tobacco stem, and measure the diameter of the tobacco stem at each node using a digital vernier caliper. Take the average of the maximum diameter of each measurement node as the average width W0 of the tobacco stem before pressing, and take the average of the minimum diameter of each measurement node as the average thickness T0 of the tobacco stem before pressing;

[0052] (4) Place the tobacco stems in each diameter interval in a controllable washing tank in turn for washing and moisture recovery. The washing cycle water temperature is (45-60)±3℃, the washing time is 5-10s, the circulating water flow rate is 0.4-0.8m / s, then the tobacco stems are balanced for 2h in an environment with a temperature of 30±2℃ and a humidity of 70±5% for moisture recovery, so that the moisture content of the tobacco stems before pressing is 26-30%, and the temperature is 30±2℃;

[0053] (5) Set the gap between the pressing rollers of the tobacco stem pressing machine to 1.0±0.1mm, then divide the tobacco stem samples in each diameter interval taken in the five times into five batches in turn for continuous roller pressing. Then, lay the pressed tobacco stems on a detection platform, use a CCD camera to obtain digital photos of the front and cross section of the pressed tobacco stems, and save and transmit them to a computer; wherein, the comparison of the appearance deformation before and after pressing of the second batch is shown in Figure 3 , and Figure 4 shows the schematic diagram of the front of the pressed tobacco stems of the second batch before and after image processing;

[0054] (6) Use image processing and measurement software (Matlab) to extract the outline of the pressed tobacco stems, perform threshold processing, pixel extraction, and pixel and geometric value data conversion on the collected pressed tobacco stem pictures, to obtain the front area S 正面 and cross-sectional area S 截面 of the pressed tobacco stems;

[0055] (7) Take 1 / 4, 1 / 2, and 3 / 4 of the width of the pressed tobacco stem as the measurement nodes (as shown in Figure 2 ​), the length of the tobacco stem corresponding to each node is measured multiple times, and the average value is taken as the length of the tobacco stem after pressing L; and the width W1 and the thickness T1 of the tobacco stem after pressing are calculated according to the following formula:

[0056] W1=S 正面 / L;T1=S 截面 / W1

[0057] In the formula, W1 is the width of the tobacco stem after pressing, S 正面 is the front area of the tobacco stem after pressing, and L is the length of the tobacco stem after pressing; T1 is the thickness of the tobacco stem after pressing, and S 截面 is the cross-sectional area of the tobacco stem after pressing.

[0058] (8) According to the width and thickness of the tobacco stem before and after pressing, the original size ratio K r0 of the tobacco stem before pressing and the deformation size ratio K r1 of the tobacco stem after pressing in different diameter intervals are calculated respectively.

[0059]

[0060] In the formula, W0 is the average width of the tobacco stem before pressing, T0 is the average thickness of the tobacco stem before pressing, W1 is the width of the tobacco stem after pressing, T1 is the thickness of the tobacco stem after pressing, m is the number of tobacco stems in different diameter intervals, and r is the diameter interval.

[0061] (9) According to the original size ratio of the tobacco stem before pressing and the deformation size ratio of the tobacco stem after pressing, the deformation characteristic index K r of the tobacco stem in different diameter intervals is calculated, and then the total deformation characteristic index K of the tobacco stem is obtained according to the content P r of the tobacco stem in different diameter intervals; wherein the deformation characteristic index K r of the tobacco stem is used to represent the quality of the tobacco stem in different diameter intervals, and the total deformation characteristic index K of the tobacco stem is used to represent the overall quality of the tobacco stem; K r and K are calculated according to the following formula respectively:

[0062]

[0063]

[0064] In the formula, K r1 is the deformation size ratio of the tobacco stem after pressing, K r0 is the original size ratio of the tobacco stem before pressing, P r is the content of the tobacco stem in different diameter intervals, and n is the number of diameter intervals.

[0065] The calculation results are shown in Tables 1-5 as follows,

[0066] Table 1 Related statistical data of the first batch of tobacco stems after pressing in continuous production

[0067]

[0068] Table 2: Relevant statistical data of continuously produced tobacco stems after stem pressing of the second batch

[0069]

[0070] Table 3: Relevant statistical data of continuously produced tobacco stems after stem pressing of the third batch

[0071]

[0072] Table 4: Relevant statistical data of continuously produced tobacco stems after stem pressing of the fourth batch

[0073]

[0074] Table 5: Relevant statistical data of continuously produced tobacco stems after stem pressing of the fifth batch

[0075]

[0076] As can be seen from Tables 1-5, with the increase of the diameter range of the tobacco stems, the stem pressing deformation characteristic index K first increases and then decreases, and the difference between the stem pressing deformation characteristic indexes K of adjacent size ranges decreases until it is negative, which is because, with the increase of the size of the tobacco stems, the tissue structure of the tobacco stems is more compact, the back permeability is not good, and the tobacco stems have a significant rebound phenomenon after stem pressing, the stem pressing effect is poor, and the difference in the stem pressing deformation characteristic index is small; the above calculation results are consistent with the actual situation, thereby indicating that the total stem pressing deformation characteristic index K defined in the present application can better evaluate the stem pressing quality and objectively reflect the true situation of the deformation quality before and after stem pressing; and the stem pressing deformation characteristic indexes K of different diameter ranges can represent the stem pressing quality in different diameter ranges, thereby providing a theoretical basis for the grouping processing of the tobacco stems. r r

[0077] (10) five times of tobacco stems of different sizes meeting the process standards are selected, 100 stems are taken each time, and are well marked; before each time of rolling, the stem pressing machine is adjusted to the best running state under the corresponding parameters, the stem pressing deformation characteristic index standard reference value K and the total stem pressing deformation characteristic index standard reference value K are measured and calculated under different diameter ranges according to the method of steps (1)-(9), and then the stem pressing quality representation evaluation coefficient k is obtained by comparing the total stem pressing deformation characteristic index of the five batches of continuously produced tobacco stems in actual production with the standard reference value, k=K / K r标 标 标 , the results are recorded in Tables 6-7, Figure 4 which shows the change of the stem pressing quality representation evaluation coefficient k with the production batch.

[0078] ​​​​Table 6 Standard reference value of deformation characteristic index of different sizes of the first batch of compressed stems

[0079]

[0080] Table 7 Evaluation coefficient of compressed stem quality

[0081]

[0082] As can be seen from Table 7, the total deformation characteristic index of the compressed stems of the five batches produced in succession gradually decreases, and the standard reference value K of the total deformation characteristic index of the compressed stems corresponding to the batches also gradually decreases. 标 There is no significant difference, and the evaluation coefficient k of the compressed stem quality also gradually decreases with the increase of the production batches (for example, Figure 5 ); this is mainly because in actual production, as the production batches are continuously produced, the working state of the compressed stem equipment is not as stable as that in the early maintenance period, and as the production is continuously carried out, the compression roller is gradually fouled, the pressure between the compression rollers is uneven, thereby indirectly affecting the quality of the compressed stems, leading to the gradual deterioration of the quality of the compressed stems. The above experimental measurement results are consistent with the actual production situation. Therefore, the greater the evaluation coefficient of the compressed stem quality is, the better the compression effect is, the closer the standard reference value of the deformation characteristic index is, and the more stable the incoming material processing or equipment working state is, and vice versa.

[0083] In addition, in actual application, the size of the evaluation coefficient of the compressed stem quality can be combined to quantitatively characterize the quality of the compressed stems. When the evaluation coefficient of the compressed stem quality is between 0.9 and 1, it is considered to be excellent, between 0.8 and 0.9, it is considered to be good, between 0.7 and 0.8, it is considered to be medium, and when k<0.7, it is considered to be poor. In this embodiment, as the production is continuously carried out, the evaluation coefficient of the compressed stem quality decreases when the production reaches the fourth batch and the fifth batch, and the grade of the compressed stems gradually decreases. At this time, it should be checked whether the working state of the equipment and the related process operation parameters are normal in time, abnormal signs of the quality of the compressed stems are found in time, the corresponding reason finding is carried out synchronously, and solving measures are taken. The equipment point inspection can also be carried out after three batches of continuous production to ensure the steady operation of the subsequent production quality.

[0084] Example 2

[0085] A compressed stem quality evaluation method, comprising the following steps:

[0086] (1) Randomly select four portions of tobacco stems with a diameter range of 4.5±0.1 mm before compression of a production line of Hubei Zhongyan Cigarette Factory, each portion having 100 tobacco stems, and mark them well;

[0087] (2) Take 1 / 4, 1 / 2, 3 / 4 of the length direction of the tobacco stem as the measurement node, rotate the tobacco stem and measure the diameter of each node corresponding to the tobacco stem by using the digital vernier caliper, take the average of the maximum value of each measurement node diameter as the average width of the tobacco stem before pressing W0, and take the average of the minimum value of each measurement node diameter as the average thickness of the tobacco stem before pressing T0;

[0088] (3) Place four tobacco stems in the controllable washing tank in turn to wash and rehydrate the tobacco stems, wherein the tobacco stem washing circulating water temperature is (45-60) ± 3℃, the tobacco stem washing time is 5-10s, the circulating water flow speed is 0.4-0.8m / s, then rehydrate the tobacco stems in an environment with a temperature of 30±2℃ and a humidity of 70±5% for 2h, so that the moisture content of the tobacco stems before pressing is 26-30%, and the temperature is 30±2℃;

[0089] (4) After maintaining and debugging the tobacco stem pressing main machine equipment to the best running state, press the four tobacco stems under the conditions that the pressing roller gap parameters are 0.9mm, 1.0mm, 1.1mm and 1.2mm, and the gap error is ±0.1mm; after pressing, respectively lay the tobacco stems on the detection loading platform, use the CCD camera to obtain the digital photos of the front and cross section of the pressed tobacco stems, and save and transmit to the computer; wherein, Figure 6 Fig. 2 shows the contrast diagram of the appearance deformation of the tobacco stem before and after pressing when the pressing roller parameter is 1.0±0.1mm;

[0090] (5) Use image processing and measurement software to process the collected pressed tobacco stem images to obtain the front area S 正面 and the cross section area S 截面 of the pressed tobacco stem;

[0091] (6) Take 1 / 4, 1 / 2, 3 / 4 of the width direction of the pressed tobacco stem as the measurement node, measure the length of the tobacco stem corresponding to each node multiple times, and take the average value as the length L of the pressed tobacco stem; and calculate the width and thickness of the pressed tobacco stem according to the following formula:

[0092] W1=S 正面 / L; T1=S 截面 / W1

[0093] In the formula, W1 is the width of the pressed tobacco stem, S 正面 is the front area of the pressed tobacco stem, and L is the length of the pressed tobacco stem; T1 is the thickness of the pressed tobacco stem, and S 截面 is the cross section area of the pressed tobacco stem.

[0094] (7) According to the width and thickness of the tobacco stem before and after pressing, calculate the original size ratio standard value K r0标 of the tobacco stem before pressing and the deformation size ratio standard value K r1标 of the pressed tobacco stem under different pressing parameters, respectively.

[0095]

[0096] In the formula, W0 is the average width of the tobacco stem before pressing, T0 is the average thickness of the tobacco stem before pressing, W1 is the width of the tobacco stem after pressing, T1 is the thickness of the tobacco stem after pressing, m is the number of tobacco stems per portion, and r is the diameter interval.

[0097] (8) According to the original size ratio standard value of the tobacco stem before pressing and the deformation size ratio standard value of the tobacco stem after pressing, the corresponding deformation characteristic index standard reference value K of the tobacco stem under different pressing parameters is calculated. r标 r标 The following formula is used for calculation:

[0098]

[0099] In the formula, K is the deformation size ratio standard value of the tobacco stem after pressing, and K is the original size ratio standard value of the tobacco stem before pressing. r1标 r0

[0100] The calculation results are shown in Table 8,

[0101] Table 8 Deformation characteristic index standard reference value of the tobacco stem under different pressing parameters

[0102]

[0103] Table 8 shows the deformation characteristic index standard reference value of the tobacco stem with a diameter range of 4.0±0.5 mm under four different pressing parameters. It can be seen that as the pressing roller gap increases, the standard reference value gradually decreases and the numerical value has obvious difference. In the actual production process, different formula raw materials require different processing parameters, and the pressing parameters naturally need to be adjusted. Therefore, according to the calculation of the deformation characteristic index standard reference value, the deformation characteristic index standard reference value of the tobacco stem of different sizes under different pressing roller gaps can be established, which provides a standard reference basis for the deformation characteristic change of the tobacco stem under different processing parameters, and further accurately calculates the pressing quality characterization evaluation coefficient, thereby supporting the pressing quality characterization evaluation under different pressing roller parameters.

[0104] The above describes the preferred embodiments of the present application, but the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, and these simple modifications all belong to the protection scope of the present application.

[0105] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present application will not further describe various possible combinations.​​​

[0106] Furthermore, the various embodiments can also be combined, if not in contradiction, as long as they do not deviate from the spirit of the present application, which should be considered as disclosed.

Claims

1. A method for evaluating stem compression quality, characterized in that: The following steps are involved: (1) taking tobacco stems of different sizes and dividing the tobacco stems into n diameter intervals according to their diameters; (2) Calculate the tobacco stem content in different diameter ranges; (3) obtaining the width and thickness of the tobacco stems before stem compression; (4) obtaining the width and thickness of the tobacco stems after the tobacco stems are compressed; (5) Calculate the original stem size ratio K before stem compression in different diameter intervals according to the following formula r0 and the ratio of tobacco stem deformation size after stem compression K r1 ; Where W0 is the width of the tobacco stem before pressing, T0 is the thickness of the tobacco stem before pressing, W1 is the width of the tobacco stem after pressing, T1 is the thickness of the tobacco stem after pressing, m is the number of tobacco stems in different diameter ranges, and r is the diameter range; (6) According to the original size ratio of the tobacco stem before pressing and the deformation size ratio of the tobacco stem after pressing, the deformation characteristic index K of the pressed stem in different diameter ranges is calculated. r , and then according to the tobacco stem content in the different diameter ranges, the total pressed stem deformation characteristic index K is obtained; K r and K are calculated using the following formulas: Where K r1 is the ratio of the tobacco stem deformation size after stem compression, K r0 is the original size ratio of tobacco stems before pressing, P r is the tobacco stem content in different diameter intervals, and n is the number of diameter intervals; (7) The total stem deformation characteristic index of tobacco stems that meet the process standards is used as the standard reference value K of the total stem deformation characteristic index. 标 , and the stem quality evaluation coefficient k is calculated based on the ratio of the total stem deformation characteristic index in actual production to the standard reference value of the total stem deformation characteristic index; the stem quality evaluation coefficient is used to quantitatively evaluate the quality of the stem, k = K / K 标 ; in, The method for obtaining the tobacco stem width and the tobacco stem thickness before stem compression in step (3) is as follows: dividing the tobacco stem into a plurality of nodes along the length direction of the tobacco stem, measuring the tobacco stem diameter corresponding to each node multiple times, and taking the average value of the maximum diameters of each measured node as the tobacco stem width before stem compression, and taking the average value of the minimum diameters of each measured node as the tobacco stem thickness before stem compression; The method for obtaining the width and thickness of the tobacco stems after the tobacco stems are compressed in step (4) is as follows: S1. Compressing the tobacco stems and obtaining front and cross-sectional photographs of the tobacco stems after the compression; wherein the tobacco stems are washed and moisturized before the compression; S2. Perform image processing on the photograph of the pressed tobacco stems to obtain the frontal area S of the pressed tobacco stems. 正面 and cross-sectional area S 截面 ; S3. Measure the stem length L after pressing, and calculate the stem width and thickness after pressing according to the following formula: W1=S 正面 / L;T1=S 截面 / W1 Where W1 is the width of the tobacco stem after pressing, S 正面 is the frontal area of ​​the tobacco stem after pressing, L is the length of the tobacco stem after pressing; T1 is the thickness of the tobacco stem after pressing, S 截面 is the cross-sectional area of ​​the tobacco stem after compression.

2. A method for evaluating stem compression quality according to claim 1, characterized in that: The number of tobacco stems in step (1) is ≥100, the diameter of the tobacco stems is ≥2.5 mm, and the length of the tobacco stems is ≥10.0 mm.

3. The method for evaluating stem compression quality according to claim 1, wherein: The nodes are located at 1 / 4, 1 / 2 and 3 / 4 of the length of the tobacco stem.

4. The method for evaluating stem compression quality according to claim 1, wherein: The tobacco stem diameter corresponding to each node is measured by rotating the tobacco stem for one circle.

5. The method for evaluating stem compression quality according to claim 1, wherein: When S1 performs the above-mentioned stem pressing, the gap between the rollers of the stem pressing machine used is (0.9~1.2)±0.1mm.

6. A method for evaluating stem compression quality according to claim 1, characterized in that: The image processing described in S2 includes tobacco stem contour extraction, threshold processing, pixel extraction, and pixel and geometric value data conversion.

7. The method for evaluating stem compression quality according to claim 1, wherein: The method for measuring the length of the compressed tobacco stems in S3 is: dividing the compressed tobacco stems into multiple nodes along the width direction of the compressed tobacco stems, measuring the length of the tobacco stems corresponding to each node multiple times, and taking the average value as the length of the compressed tobacco stems.

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