A method for evaluating the permanent deformation effect of tobacco stems

Abstract

The present invention discloses a method for evaluating the permanent deformation effect of tobacco stems, comprising the following steps: (1) measuring the equivalent thickness h0 of the tobacco stems before pressing; (2) measuring the equivalent thickness h0 of the tobacco stems before pressing; rg The tobacco stems are pressed at a certain process flow rate; (3) the equivalent thickness h of the tobacco stems after pressing is measured. cs (4) Calculate the deformation of the tobacco stem ε according to the following formula jcs :ε jcs =(h0-h cs ) / h0; (5) Calculate the equivalent deformation ε of the tobacco stem according to the following formula dcs :ε dcs =(2.009-h rg ) / 2.9377; (6) Calculate ε jcs With ε dcs The difference △ε cs =ε jcs -ε dcs ; (7) According to △ε cs The value of is used to evaluate the permanent deformation effect of tobacco stems.

Description

Technical Field

[0001] The invention belongs to the technical field of tobacco processing, and in particular provides a method for quantitatively detecting the deformation amount of tobacco stems. Background Art

[0002] Indicators such as the shape of cut stems, such as their thread-like shape and appearance color, not only affect the appearance quality of finished tobacco, but are also key control factors affecting the blending effect of cut stems, the draw resistance, hardness, ventilation rate and other indicators of finished cigarettes. How to improve the thread-like effect of cut stems, and thus improve the appearance of cut stems and the blending effect of cut stems, is one of the common bottleneck problems faced by the cut stem making process, and is also one of the important issues that restrict the use value and usage ratio of cut stems in the formula.

[0003] The stem pressing process for cut tobacco stems often employs thinning, double pressing, and multiple cutting techniques to control the width distribution of the cut tobacco stems, achieving a consistent, stringy appearance while significantly reducing the proportion of flaky stems. To reduce stem thickness and achieve thinning, the gap between the rollers in the stem press is used as the primary means of controlling stem thickness. This has become a widely used process for improving the stringiness of cut tobacco stems.

[0004] When compressing loose agricultural materials such as tobacco stems, rheology is often used to study the material's stress relaxation and creep properties. After the compressed material's stress relaxes, the stems' elastic deformation fully recovers, resulting in permanent deformation composed of residual elastic deformation and plastic deformation. This can be used to analyze and characterize the post-compression shaping of tobacco stems during the stem-cutting process at a macroscopic level.

[0005] At present, there is no unified standard in the industry for how to characterize the filamentous morphology and shredding effect of tobacco stems after shredding. The reason is that the tobacco industry has not yet established a quantitative detection method for the thickness of pressed stems or the deformation of tobacco stems. In particular, when carrying out maintenance work on the thinning process, it is often manifested that different types of stem presses, under the same roller gap processing conditions, have significant differences in filamentous indicators such as the width of the tobacco stems after shredding. There is a lack of standardized and quantifiable means to evaluate and analyze the effect of the stem thinning process.

[0006] The present invention has been proposed to solve the above-mentioned problems. Summary of the Invention

[0007] The present invention provides a quantitative detection method for the deformation of tobacco stems, and evaluates the permanent deformation effect of tobacco stems based on the quantitative detection results of the deformation of tobacco stems. The evaluation method of the present invention provides a basis for quantitatively analyzing the inter-batch and intra-batch stability of the stem pressing effect of a stem press and the differences in the properties of different tobacco stem raw materials, and also provides a basis for process maintenance and parameter adjustment of the stem press. The evaluation method of the present invention indirectly provides a basis for improving the filamentous appearance quality of shredded stems, enhancing the use value of shredded stems and the homogenization level of the stem pressing effect. The evaluation method of the present invention can predict the permanent deformation effect of tobacco stems after pressing, because this indicator is one of the key control indicators that affect the filamentous appearance quality of shredded stems. At the same time, the measurement method selected by the present invention obtains the permanent deformation of tobacco stems and the equivalent thickness of tobacco stems, which is convenient, has clear physical meaning, and has a high degree of differentiation in measurement results.

[0008] The technical solutions of the present invention are as follows:

[0009] The present invention provides a method for evaluating the permanent deformation effect of tobacco stems, comprising the following steps:

[0010] (1) Measure the equivalent thickness h0 of the tobacco stem before pressing;

[0011] (2) When the gap between the rollers is h rg And the tobacco stems are pressed under a certain process flow rate;

[0012] (3) Measure the equivalent thickness h of the tobacco stem after pressing cs ;

[0013] (4) Calculate the stem deformation ε according to the following formula jcs :ε jcs =(h0-h cs ) / h0;

[0014] (5) Calculate the equivalent deformation ε of the tobacco stem according to the following formula dcs :ε dcs =(2.009-h rg ) / 2.9377;

[0015] (6) Calculation of ε jcs With ε dcs The difference △ε cs =ε jcs -ε dcs ;

[0016] (7) According to △ε cs The value of is used to evaluate the permanent deformation effect of tobacco stems.

[0017] Preferably, the step (1) of measuring the equivalent thickness of the tobacco stems before stem pressing is as follows: measuring at least five measuring points at equal intervals along the length of each tobacco stem, and solving the average value, which is the equivalent thickness h0 of the tobacco stems before stem pressing.

[0018] Preferably, the measurement sample requirements for the tobacco stems before pressing in step (1) are as follows: at the material delivery trough, a single sampling of ≥100g of tobacco stem sample is performed, the sample is prepared by the quartering method, the tobacco stem test sample for each test is ≥10.0g, and the test tobacco stem particles are ≥25.

[0019] Preferably, the step (3) of measuring the equivalent thickness of the tobacco stems after pressing is as follows: sampling at the outlet of the stem press, placing the sample at a constant temperature and humidity of 22°C and 60% humidity for more than 10 minutes, and then measuring at least five points at equal intervals along the length of each tobacco stem, and solving the average value, which is the equivalent thickness h of the tobacco stems after pressing. cs .

[0020] Preferably, the measurement sample requirements of the tobacco stems after stem pressing in step (3) are as follows: sampling is performed at the outlet of the stem press, a single sampling of ≥100 g of tobacco stem sample is performed, the sample is prepared by the quartering method, the tobacco stem test sample for each test is ≥10.0 g, and the test tobacco stem particles are ≥25.

[0021] Preferably, Δε cs The closer the value is to 0, the better the permanent deformation effect of the tobacco stems; that is, the better the shaping effect of the tobacco stems after pressing. cs The value of is based on 0.055; cs The value of is less than 0.055, indicating that the permanent deformation effect of tobacco stems is good; △ε cs The value of is greater than 0.055, indicating that the permanent deformation effect of tobacco stems is poor. In order to improve the silky effect of the stems, it is necessary to carry out maintenance on the stem pressing effect of the stem press.

[0022] Beneficial effects of the present invention:

[0023] 1. The present invention's method for determining tobacco stem permanent deformation and equivalent stem thickness is characterized by convenience, clear physical meaning, and high discriminability. This evaluation method can predict the permanent deformation of pressed tobacco stems, a key indicator of the quality of the stem's silky appearance.

[0024] 2. The evaluation and measurement method of the present invention offers significant advantages in achieving homogenized stem compression. The development of this prediction method shifts the traditional process model from measuring stem compression performance based on external settings within the stem press to one guided by the permanent deformation of the tobacco stems after compression. This allows for a more scientific and precise improvement in the homogenization of tobacco stem compression.

[0025] 3. The evaluation method of the present invention can quantitatively analyze the inter-batch and intra-batch stability of the stem pressing effect of the stem pressing machine and the differences in the properties of different tobacco stem raw materials. It has significant technical advantages in improving the stability of the appearance quality of the cut stems after the stems are pressed into shreds.

[0026] 4. The evaluation method of this invention can predict whether the setting of the roller gap in a stem press is appropriate, providing guidance for the calibration or standardization of the stem press model. It can also evaluate the stem pressing performance of different stem presses, providing a basis for process maintenance and parameter adjustment. This evaluation method indirectly provides a basis for improving the appearance quality of shredded stems, enhancing the usability of shredded stems, and achieving a homogenized stem pressing effect. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and beneficial effects of the present invention clearer, a detailed description will be given below with reference to embodiments to facilitate understanding by technicians.

[0028] Example 1: Evaluation of the permanent deformation of tobacco stems of a certain brand Z after stem compression.

[0029] In the tobacco stem cutting process, the moisture content of the tobacco stems before pressing was 33.5%. The stem pressing machine was SY115, manufactured by Kunming Ship Equipment Group Co., Ltd. The roller gap was set to 0.8 mm, and the process flow rate was 1500 kg / h. The steps were as follows:

[0030] (1) Use a vernier caliper to measure the actual thickness of the incoming tobacco stems, i.e., the equivalent thickness h0 perpendicular to the stem core. Measure the pressed stem thickness at five points along the length of each tobacco stem at equal intervals, and mark them as h 01 、h 02 、h 03 、h 04 、h 05 The test sample weight is 10.1335 g, and the number of tobacco stem particles is 32. The average thickness of all the above 5 points of the tobacco stem is solved, and the equivalent thickness of the tobacco stem h0 is 2.588 mm.

[0031] (2) The rollers are set to a gap of 0.8 mm to compress the stems; samples are taken at the exit of the stem press and left to stand for more than 10 minutes under constant temperature and humidity conditions (22°C, 60% humidity). The equivalent thickness of the tobacco stems after compression is measured with a vernier caliper. cs Measure the thickness of the pressed stem at 5 points along the length of the tobacco stem and mark it as h cs1 、h cs2 、h cs3 、h cs4 、h cs5 , solve the average value; the equivalent thickness of tobacco stems at the outlet of the stem press h cs is 1.379;

[0032]

[0033] (3) The known equivalent thickness of incoming tobacco stem h0 and the equivalent thickness of pressed tobacco stem h cs Substituting into formula (1) to calculate, the obtained tobacco stem deformation εjcs is 0.467;

[0034] ε jcs =(h0-h cs ) / h0; (1)

[0035] (4) Calculate the equivalent deformation ε of the tobacco stem according to the following formula dcs It is 0.412.

[0036] ε dcs =(2.009-h rg ) / 2.9377 (2)

[0037] (5) Calculation of ε jcs With ε dcs The difference △ε cs =ε jcs -ε dcs , which is 0.055

[0038] (6)△ε cs It is 0.055, indicating that the tobacco stem permanent deformation effect of this embodiment is better.

[0039] Example 2: Evaluation of the permanent deformation of tobacco stems of a certain brand Y after stem compression.

[0040] In the tobacco stem shred production section, the moisture content of the tobacco stems before pressing is 31.5%. The roller gap is set to 0.8 mm, and the process flow rate is 1500 kg / h. The steps are as follows:

[0041] (1) Use a vernier caliper to measure the actual thickness of the incoming tobacco stems, i.e., the equivalent thickness h0 perpendicular to the stem core. Measure the pressed stem thickness at five points along the length of each tobacco stem at equal intervals, and mark them as h 01 、h 02 、h 03 、h 04 、h 05 The test sample weight is 10.2337 g, and the number of tobacco stem particles is 36. The average thickness of all the above tobacco stems at 5 points is solved, and the equivalent thickness of the tobacco stem h0 is 2.612 mm.

[0042] (2) The rollers are set to a gap of 0.8 mm to compress the stems; samples are taken at the exit of the stem press and left to stand for more than 10 minutes under constant temperature and humidity conditions (22°C, 60% humidity). The equivalent thickness of the tobacco stems after compression is measured with a vernier caliper. cs Measure the thickness of the pressed stem at 5 points along the length of the tobacco stem and mark it as h cs1 、h cs2 、h cs3 、h cs4 、h cs5, solve the average value; the equivalent thickness of tobacco stems at the outlet of the stem press h cs is 1.815;

[0043]

[0044] (3) The known equivalent thickness of incoming tobacco stem h0 and the equivalent thickness of pressed tobacco stem h cs Substituting into formula (1) to calculate, the obtained tobacco stem deformation ε jcs is 0.305;

[0045] ε jcs =(h0-h cs ) / h0; (1)

[0046] (4) Calculate the equivalent deformation ε of the tobacco stem according to the following formula dcs It is 0.412.

[0047] ε dcs =(2.009-h rg ) / 2.9377 (2)

[0048] (5) Calculation of ε jcs With ε dcs The difference △ε cs =ε jcs -ε dcs , which is 0.106

[0049] (6)△ε cs It is 0.106, which is greater than 0.05. After the tobacco stems are shredded, the width of the stems is larger, the difference in the shredded effect is obvious, and the number of flaky stems is significantly increased. In order to improve the shredded effect of the stems, it is necessary to carry out maintenance on the pressing effect of the stem press.

[0050] Example 3: Difference Δε cs Greater maintenance approach.

[0051] The parameters of the incoming tobacco stems and the stem pressing equipment are the same as those in Example 2. Only the stem pressing gap of the stem pressing machine is controlled, and the effect of the difference Δε is mainly introduced. cs control steps.

[0052] (1) Calibration of the stem pressing gap of the stem pressing machine, the default value is 0.8mm;

[0053] Under normal production conditions, tin bars with a diameter of 2.3mm and a length of 50mm are placed in the left, middle, and right positions of the vibrating trough in front of the stem press, mixed with tobacco stems. Three tin bars are placed in each position. After the tin bars are sorted out, the thickness of the tin bars is measured with a micrometer, and the average value of the thickness of the tin bars is calculated as h. rgb , retain three valid data.

[0054]

[0055] (2) Determine the control accuracy of the stem pressing machine's stem pressing gap; according to the technical requirement of control accuracy ±0.05mm, the average value of the tin bar thickness in step (1) h rgb Significantly greater than h rg The preset value is 0.8mm, and the difference is greater than 0.2mm, which exceeds the technical requirements for the control accuracy of the stem press.

[0056] (3) After the stem pressing gap of the stem pressing machine is calibrated, the steps of Example (2) are repeated to obtain the equivalent thickness h of the tobacco stem at the outlet of the stem pressing machine. cs is 1.499, and the corresponding stem deformation ε jcs is 0.426; tobacco stem deformation ε jcs Equivalent deformation of tobacco stem corresponding to 0.8mm stem gap ε dcs Compared with the value of 0.412, the difference is 0.014, which is much smaller than 0.055; it is significantly reduced.

[0057] This example further demonstrates that the method for evaluating the permanent deformation effect of tobacco stems of the present invention is an effective means for evaluating whether a stem pressing machine and its operating conditions are good.

[0058] Example 4 compares the changes in the shape of the stems before and after maintenance of the stem pressing gap of the stem pressing machine.

[0059] The parameters of the incoming tobacco stems and the stem pressing equipment are the same as those in Example 2 and Example 3. That is, the tobacco stems with different degrees of permanent deformation are compared to see the difference in the filamentous effect after shredding.

[0060] According to the image detection method of the tobacco stem thread-like effect of patents CN108871187B and CN103162626B, the thread-like effect of tobacco stems before and after the maintenance of the tobacco stem gap was detected. The detection results are shown in the following table.

[0061]

[0062] The above data show that different pressing gaps have a significant impact on the width, length, and curl of the tobacco stems after being shredded. Under the condition of not maintaining the pressing gap, the tobacco stem gap of the pressing machine is the same as 0.8mm, and the shape of the tobacco stems is obviously different. The reason is essentially the deformation of the tobacco stems ε jcs The significant difference in the width of the stems is the main influencing factor leading to the difference in the width of the stems.

[0063] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the invention as claimed.

Claims

1. A method for evaluating the permanent deformation effect of tobacco stems, characterized in that: The steps include: (1) Measure the equivalent thickness h0 of the tobacco stem before pressing; (2) When the gap between the rollers is h rg And the tobacco stems are pressed under a certain process flow rate; (3) Measure the equivalent thickness h of the tobacco stem after pressing cs ; (4) Calculate the stem deformation ε according to the following formula jcs :ε jcs =(h0-h cs ) / h0; (5) Calculate the equivalent deformation ε of the tobacco stem according to the following formula dcs :ε dcs =(2.009-h rg ) / 2.9377; (6) Calculation of ε jcs With ε dcs The difference △ε cs =ε jcs -ε dcs ; (7) According to △ε cs The value of is used to evaluate the permanent deformation effect of tobacco stems; cs The closer the value is to 0, the better the permanent deformation effect of the tobacco stem.

2. The prediction method according to claim 1, characterized in that Step (1) The steps for measuring the equivalent thickness of the tobacco stems before stem pressing are as follows: along the length direction of the tobacco stems, each tobacco stem is measured at no less than five measuring points at equal intervals, and the average value is solved, which is the equivalent thickness h0 of the tobacco stems before stem pressing.

3. The prediction method according to claim 1 or 2, characterized in that: The measurement sample requirements for the tobacco stems before pressing in step (1) are as follows: at the place where the conveyor vibration trough drops materials, a single sampling of ≥100g of tobacco stem samples is carried out, the sample is prepared by the quartering method, the tobacco stem test sample for each test is ≥10.0g, and the test tobacco stem particles are ≥25.

4. The prediction method according to claim 1, wherein: Step (3) of measuring the equivalent thickness of the pressed tobacco stems is as follows: sampling at the outlet of the press, placing the sample at a constant temperature and humidity of 22°C and 60% humidity for more than 10 minutes, measuring at least five points at equal intervals along the length of each tobacco stem, and calculating the average value, which is the equivalent thickness h of the pressed tobacco stems. cs .

5. The prediction method according to claim 1 or 4, characterized in that: The measurement sample requirements for the tobacco stems after stem pressing in step (3) are as follows: sampling at the outlet of the stem press, a single sampling of ≥100g of tobacco stem sample, sample preparation using the quartering method, a tobacco stem test sample for each test of ≥10.0g, and ≥25 test tobacco stem particles.

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