A method for predicting the pressure roller gap of a pressure chamber based on the permanent deformation of tobacco stems

Abstract

The application discloses a method for predicting the clearance of a pressure roller of a pressure stalk machine based on permanent deformation of tobacco stalks, which comprises the following steps: (1) measuring the equivalent thickness h0 of the tobacco stalks before pressure; (2) setting the clearance of the pressure roller as h Srg , and pressure-rolling the tobacco stalks under a certain process flow; (3) measuring the equivalent thickness h cs of the tobacco stalks after pressure-rolling; (4) calculating the permanent deformation of the tobacco stalks according to the following formula: ε cs ; (5) calculating the equivalent clearance of the pressure roller of the pressure stalk machine as h rg ; (6) calculating the difference Δh rg between the set clearance of the pressure roller and the equivalent clearance of the pressure roller; and (7) predicting whether the set clearance of the pressure roller of the pressure stalk machine is reasonable according to the value of Δh rg . The application also discloses the use of the predicting method for evaluating the pressure-rolling effect of different pressure stalk machines.

Description

Technical Field

[0001] This invention belongs to the field of tobacco processing technology, specifically relating to a method for predicting the gap of the pressing rollers of a pressing machine based on the permanent deformation of tobacco stems, which is applied to the evaluation of the pressing effect of different pressing machines. Background Technology

[0002] The pressing process for tobacco stems often employs techniques such as thin pressing, double pressing, and re-cutting to control the width distribution of the cut stems, aiming to achieve a filamentous effect with a consistent width while significantly reducing the proportion of sheet-like stems. To reduce the thickness of the pressed tobacco stems and achieve a thin pressing process, using the gap between the pressing rollers of the pressing machine as the primary means of controlling stem thickness has become a widely used process technology in improving the filamentous shape of the stems.

[0003] When compressing loose agricultural materials such as tobacco stems, rheology is often used to study the stress relaxation and creep characteristics of the materials. After the stress of the compressed material relaxes, the elastic deformation of the tobacco stem is fully restored, and the resulting permanent deformation consists of residual elastic deformation and plastic deformation. Macroscopically, this can be used to analyze and characterize the shaping effect of the compressed tobacco stem during the tobacco shredding process.

[0004] However, the actual effect of the thin-pressing process on tobacco stems is still unclear. This is evident in the significant differences in the filament shape of the tobacco stems after pressing, even with the same roller gap, between different models of pressing machines. This is a key factor restricting the homogenization of tobacco stem filament production, indicating that the setting gap of the pressing machine does not directly correlate with the permanent deformation of the tobacco stems. Furthermore, the tobacco industry has not yet established a quantitative detection method for pressing thickness or tobacco stem deformation.

[0005] This invention proposes a method for predicting the rationality of the gap setting of the pressing rollers in a tobacco stem pressing machine based on the permanent deformation of the tobacco stems. Summary of the Invention

[0006] This invention provides a method for predicting the rationality of the equivalent pressure roller gap setting based on the permanent deformation of tobacco stems. The prediction method first quantifies the magnitude of the permanent deformation of the pressed tobacco stems, as this is one of the key control indicators affecting the filamentous appearance quality of the stems. This method can predict whether the setting of the pressure roller gap in a stem pressing machine is reasonable, and if the setting is unreasonable, it provides guidance on how to set it, and on calibration or standardization of the machine model; it also allows for the evaluation of the pressing effect of different stem pressing machines. This method provides a basis for quantitatively analyzing the batch-to-batch and intra-batch stability of the pressing effect of stem pressing machines, as well as the differences in the properties of different tobacco stem raw materials, and also provides a basis for the process maintenance and parameter adjustment of stem pressing machines. This method indirectly provides a basis for improving the filamentous appearance quality of the stems, enhancing the usability of the stems, and increasing the homogenization level of the pressing effect.

[0007] The technical solution of the present invention is as follows:

[0008] The first aspect of this invention discloses a method for predicting the gap of the pressing rollers of a tobacco stem pressing machine based on the permanent deformation of the tobacco stem, comprising the following steps:

[0009] (1) Measure the equivalent thickness h0 of the tobacco stem before pressing;

[0010] (2) The gap between the pressure rollers is set to h. Srg Furthermore, the tobacco stems are compressed under a certain process flow rate;

[0011] (3) Measure the equivalent thickness h of the tobacco stem after pressing. cs ;

[0012] (4) Calculate the permanent deformation ε of the tobacco stem according to the following formula. cs ε cs =(h0-h cs ) / h0;

[0013] (5) Calculate the equivalent pressure roller gap h of the pressing machine. rg :h rg =-A*ε cs +b, where A and b are permanent deformation parameters;

[0014] (6) Calculate the difference △h between the set pressure roller gap and the equivalent pressure roller gap. rg =h Srg -h rg ;

[0015] (7) According to △h rg The value is used to predict whether the gap setting of the pressing rollers of the pressing machine is reasonable.

[0016] Preferably, the measurement steps for the equivalent thickness of the tobacco stem before pressing in step (1) are as follows: along the length of the tobacco stem, at least five measurement points are measured at equal intervals for each tobacco stem, and the average value is calculated, which is the equivalent thickness h0 of the tobacco stem before pressing; the sample requirements are as follows: at the material drop point of the conveying trough, a single sample of ≥100g tobacco stem is taken, the sample is prepared by the quartering method, the tobacco stem test sample provided for each test is ≥10.0g, and the test tobacco stem particles are ≥25.

[0017] Preferably, the measurement steps for the equivalent thickness of the tobacco stem after pressing in step (3) are as follows: a sample is taken at the outlet of the pressing machine, placed under constant temperature and humidity conditions of 22°C and 60% for more than 10 minutes, and then at least five measurement points are measured at equal intervals along the length of each tobacco stem. The average value is calculated, which is the equivalent thickness h of the tobacco stem after pressing. cs The sample requirements are as follows: a single sample of ≥100g tobacco stems should be taken, and the sample should be prepared using the quartering method. Each test sample of tobacco stems should be ≥10.0g, and the test sample should contain ≥25 tobacco stem particles.

[0018] Preferably, the values ​​of permanent deformation parameters A and b in step (5) can be obtained by linear regression modeling. In this invention, A is -2.9377 and b is 2.009.

[0019] Preferably, step (7) is based on △h rg The steps to predict whether the setting of the gap between the pressure rollers of the stalk press is reasonable are as follows:

[0020] (A) If △h rg If the absolute value is ≤0.05mm, then the gap setting of the pressing rollers of the pressing machine is reasonable;

[0021] (B) If △h rg The absolute value is: 0.05mm < Δh rg If the gap is ≤0.1mm, the setting of the pressure roller gap of the stalk pressing machine is unreasonable and needs to be reset. When resetting the pressure roller gap, use a step size of 0.1mm or less, generally 0.05mm. Adjust the pressure roller gap downwards or upwards according to the magnitude of the positive or negative deviation of the equivalent pressure roller gap, until Δh is reached. rg The absolute value is: ≤0.05mm;

[0022] (C) If △h rg The absolute value is: △h rg If the deviation is greater than 0.1mm, the pressing machine needs to be calibrated or recalibrated. The calibration or recalibration steps are as follows: using a step size greater than 0.1mm, adjust the pressing roller gap of the pressing machine downwards or upwards according to the magnitude of the positive and negative deviation of the equivalent pressing roller gap, until Δh is reached. rg The absolute value is: ≤0.05mm.

[0023] The second aspect of this invention discloses the prediction method used for evaluating the stomatization effect of different stomatizers.

[0024] Beneficial effects of this invention:

[0025] 1. The prediction method of this invention uses a measurement method that is convenient, has clear physical meaning, and provides high distinguishability of test results for obtaining the permanent deformation and equivalent thickness of tobacco stems. The measurement method of this invention can quantify the magnitude of the permanent deformation of the tobacco stem after compression, as this indicator is one of the key control indicators affecting the filamentous appearance quality of the stem.

[0026] 2. The prediction method of this invention has significant advantages in homogenizing the effect of tobacco stem pressing. The establishment of the prediction method of this invention changes the traditional process mode of measuring the effect of tobacco stem pressing by external settings of the pressing machine, and transforms it into a pressing mode guided by the permanent deformation of the tobacco stem after pressing. This transformation can more scientifically and accurately improve the homogenization level of tobacco stem pressing effect.

[0027] 3. The prediction method of the present invention can quantitatively analyze the batch-to-batch and intra-batch stability of the pressing effect of the pressing machine and the differences in the properties of different tobacco stem raw materials by calculating the permanent deformation amount and equivalent thickness of the tobacco stem. It has significant technical advantages in improving the appearance quality stability of the tobacco stem shreds after the tobacco stems are formed.

[0028] 4. The prediction method of this invention can predict whether the setting of the gap between the pressing rollers of a stem pressing machine is reasonable, and if the setting is unreasonable, it provides guidance on how to set it and how to calibrate or standardize the machine. It can also evaluate the stem pressing effect of different stem pressing machines. This provides a basis for quantitatively analyzing the batch-to-batch and intra-batch stability of the stem pressing effect and the differences in the properties of different tobacco stem raw materials; it also provides a basis for the process maintenance and parameter adjustment of the stem pressing machine. The prediction method of this invention indirectly provides a basis for improving the filamentous appearance quality of the stems, enhancing the usability of the stems, and increasing the homogenization level of the stem pressing effect.

[0029] 5. The prediction method of the present invention can construct different quantitative relationships between the permanent deformation of tobacco stems and the equivalent gap of the pressing rollers of the pressing machine according to the differences in the properties of different tobacco stem raw materials. This can be used to carry out research on different tobacco stem grouping processing technology, and continuously improve the homogenization control level of tobacco stem pressing effect and the filament processing effect of stems after forming into fibers. Detailed Implementation

[0030] To make the objectives, technical solutions, and beneficial effects of this invention clearer, detailed descriptions will be provided below in conjunction with embodiments to facilitate understanding by those skilled in the art.

[0031] Example 1: Construction of a prediction model for permanent deformation of tobacco stems after pressing of a certain brand of tobacco stems.

[0032] In the tobacco stem processing section, the moisture content of the tobacco stems before pressing is 33.5%. The gap between the pressing rollers of the pressing machine is set to 0.6mm~1.0mm, the step size is 0.1mm, and the process flow rate is 3000kg / h. The steps are as follows:

[0033] (1) The actual thickness of the incoming tobacco stems is measured using vernier calipers, i.e., the equivalent thickness h0 perpendicular to the stem core direction; along the length of the tobacco stem, the thickness of the pressed stem is measured at 5 points at equal intervals for each tobacco stem, and this thickness is marked as h. 01 h 02 h 03 h 04 h 05 The test sample size was 10.2553g, and the number of tobacco stem particles was 37. The average thickness of all five points on the tobacco stems was calculated and denoted as the equivalent thickness h0 of the tobacco stem. The results are shown in the table below.

[0034]

[0035] (2) Under constant temperature and humidity conditions (22℃, 60% humidity), for the five samples mentioned above, after pressing the tobacco stems, let them stand for more than 10 minutes, and use vernier calipers to measure the equivalent thickness h of the tobacco stems after pressing. cs Along the length of the tobacco stem, the thickness of the stem compression was measured at 5 points, and this thickness was marked as h. cs1 h cs2 h cs3 h cs4 h cs5 The test sample size was 10.1447g, and the number of tobacco stem particles was 33. The average thickness of all five points on the tobacco stems was calculated and denoted as the equivalent thickness h of the tobacco stem. cs As shown in the table above;

[0036] (3) The known equivalent thickness h0 of the incoming tobacco stem and the equivalent thickness h of the compressed tobacco stem are... cs Substitute into formula (1) to calculate the permanent deformation ε of the tobacco stem. cs ;

[0037] ε cs =(h0-h cs ) / h0 (1)

[0038] (4) If the gap between the pressure rollers of the calibrated pressing machine is h rg Its permanent deformation ε of tobacco stem cs The following relational model exists, as shown in equation (2).

[0039] h rg =-2.9377*ε cs +2.009 (2)

[0040] Example 2: Prediction of the setting of the pressure roller gap of the stalk press.

[0041] In the tobacco stem making section, the moisture content of the tobacco stems before pressing is 33.5%; the pressing machine is model B, SY115, manufactured by Kunming Shipbuilding Equipment Group Co., Ltd.; the roller gap is set to 0.8mm, and the process flow rate is 1500kg / h; the steps are as follows:

[0042] (1) The actual thickness of the incoming tobacco stems is measured using vernier calipers, i.e., the equivalent thickness h0 perpendicular to the stem core direction; along the length of the tobacco stem, the thickness of the pressed stem is measured at 5 points at equal intervals for each tobacco stem, and this thickness is marked as h. 01 h 02 h 03 h 04 h 05 The sample size was 11.5524g, and the number of tobacco stems was 42. The average thickness of the tobacco stems at 5 points was calculated, and the equivalent thickness h0 of the tobacco stems was 2.588mm.

[0043] (2) Setting gap h of pressure roller Srg The thickness was 0.8 mm. A sample was taken at outlet B of the tobacco stem pressing machine and then placed under constant temperature and humidity conditions (22℃, 60% humidity) to allow the pressed tobacco stems to stand for more than 10 minutes. The equivalent thickness h of the pressed tobacco stems was measured with vernier calipers. cs Along the length of the tobacco stem, the thickness of the stem compression was measured at 5 points, and this thickness was marked as h. cs 1. h cs 2. h cs 3. h cs 4. h cs5 The test sample size was 10.8773g, and the number of tobacco stems was 35. The average thickness of the tobacco stems at 5 points was calculated. The equivalent thickness h of the tobacco stems at the B outlet of the stem press was also calculated. Bcs It is 1.379;

[0044]

[0045] (3) The known equivalent thickness h0 of the incoming tobacco stem and the equivalent thickness h of the compressed tobacco stem are... cs Substituting into formula (1), the permanent deformation ε of the tobacco stem corresponding to the stem pressing machine B is... cs It is 0.467;

[0046] ε cs =(h0-h cs ) / h0 (1)

[0047] roller gap (mm) Permanent deformation of the tobacco stem after pressing 0.8 0.467

[0048] (4) Permanently deform the tobacco stem ε Bcs Substituting these values ​​into equation (2) in sequence, the equivalent gap of the pressing rollers of the pressing machine, h, is calculated. rg It is 0.6365mm.

[0049] h rg =-2.9377*ε cs +2.009 (2)

[0050]

[0051] (5) Calculate the difference △h between the set pressure roller gap and the equivalent pressure roller gap. rg =h Srg -h rg , △h rg It is -0.1635mm;

[0052] (6) Predict whether the setting of the pressure roller gap of the pressing machine is reasonable; because 0.1635mm>0.1mm, the pressing machine model needs to be calibrated or standardized; until the equivalent pressure roller gap difference value Δh is reached. rg A diameter of less than 0.05mm is required to meet the requirements.

[0053] Example 3: Evaluation of the effects of different stem pressing machines.

[0054] In the tobacco stem processing section, the moisture content of the tobacco stems before pressing was 33.5%; pressing machine A was model IB-F2000, manufactured by Garbuio, Germany; pressing machine B was model the same as in Example 2; the gap between the pressing rollers of both pressing machines was set to 0.8 mm, and the process flow rate was 1500 kg / h. The evaluation steps for the pressing effect of the two pressing machines are as follows:

[0055] (1) The actual thickness of the incoming tobacco stems is measured using vernier calipers, i.e., the equivalent thickness h0 perpendicular to the stem core direction; along the length of the tobacco stem, the thickness of the pressed stem is measured at 5 points at equal intervals for each tobacco stem, and this thickness is marked as h. 01 h 02 h 03 h 04 h 05 The sample size was 10.9881g, and the number of tobacco stems was 32. The average thickness of all 5 points of the tobacco stems was calculated and marked as the equivalent thickness h0 of the tobacco stems, which was 2.588mm.

[0056] (2) Take samples of the pressed tobacco stems from the outlets of pressing machine A and pressing machine B respectively, and then place them under constant temperature and humidity conditions (22℃, 60% humidity) for more than 10 minutes. Use vernier calipers to measure the equivalent thickness h of the pressed tobacco stems. cs Along the length of the tobacco stem, the thickness of the stem compression was measured at 5 points, and this thickness was marked as h. cs1 h cs2 h cs3 h cs4 h cs5 The sample weight of the tobacco stem press A was 11.3817g, with 34 tobacco stem particles; the sample weight of the tobacco stem press B was 10.8226g, with 31 tobacco stem particles. Calculate the average thickness of the tobacco stems at 5 points for all the above tests. The equivalent thickness of the tobacco stems at the outlets of the tobacco stem presses A and B is denoted as h. Acs h Bcs ;

[0057]

[0058] (3) The known equivalent thickness h0 of the incoming tobacco stem and the equivalent thickness h of the compressed tobacco stem are... Acs h Bcs Substituting into the following formula, the permanent deformation of the tobacco stems corresponding to pressing machine A and pressing machine B are respectively denoted as ε. Acs ε Bcs ;

[0059] ε cs =(h0-hcs ) / h0

[0060]

[0061] (4) Permanently deform the tobacco stem ε Acs ε Bcs Substitute the values ​​into the following formulas sequentially to calculate the equivalent values ​​of the gap between the pressure rollers of the pressing machines; the equivalent values ​​of the pressure gap for pressing machines A and B are respectively labeled as h. Arg h Brg ;

[0062] h rg =-2.9377*ε cs +2.009

[0063]

[0064] (5) Calculate the difference Δh between the set pressure roller gap and the equivalent pressure roller gap for both the stalk press A and the stalk press B. rg =h Srg -h rg ;Δh Arg and Δh Brg The values ​​are shown in the table above;

[0065] (6) Evaluate the effects of different destemming machines on destemming:

[0066] ① Δh of the stem pressing machine A Arg <0.05mm, the gap setting of the A pressure roller of the stem pressing machine is reasonable, meets the process requirements, and the stem pressing effect is good;

[0067] ② Δh of the stem pressing machine B Arg >0.1mm, the gap setting of the B pressure roller of the stalk pressing machine is unreasonable, resulting in poor stalk pressing effect; the stalk pressing gap of the B pressure roller of the stalk pressing machine needs to be reset; repeat the above steps (1)-(4) until Δh rg The gap must be less than 0.05mm to meet the requirements; after adjustment, the gap of the stem pressing machine B was reset to 0.95mm to meet the requirements.

[0068] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for predicting the gap between the pressure rollers of a tobacco stem pressing machine based on the permanent deformation of the tobacco stem, characterized in that, Includes the following steps: (1) Measure the equivalent thickness h0 of the tobacco stem before pressing; (2) When the gap between the pressure rollers is set to h Srg Furthermore, the tobacco stems are compressed under a certain process flow rate; (3) Measure the equivalent thickness h of the tobacco stem after pressing. cs ; (4) Calculate the permanent deformation of the tobacco stem according to the following formula. : ; (5) Calculate the equivalent pressure roller gap h of the stalk press. rg : Where A and b are permanent deformation parameters; the value of A is -2.9377 and the value of b is 2.009; (6) Calculate the difference Δh between the set pressure roller gap and the equivalent pressure roller gap. rg =h Srg -h rg ; (7) According to △h rg The value predicts whether the setting of the gap between the pressing rollers of the stalk pressing machine is reasonable; The steps are as follows: (A) If △h rg If the absolute value is ≤0.05mm, then the gap setting of the pressing rollers of the pressing machine is reasonable; (B) If △h rg The absolute value is: 0.05mm < Δh rg If the gap is ≤0.1mm, the gap setting of the pressing rollers of the pressing machine is unreasonable and needs to be reset. (C) If △h rg The absolute value is: △h rg If the error is greater than 0.1mm, the machine model of the stem pressing machine needs to be calibrated or standardized. Step (1) The measurement steps for the equivalent thickness of the tobacco stem before pressing are as follows: along the length of the tobacco stem, at least five measurement points are measured at equal intervals for each tobacco stem, and the average value is calculated, which is the equivalent thickness h0 of the tobacco stem before pressing; the sample requirements are as follows: at the material drop point of the conveying trough, a single sample of ≥100g tobacco stem is taken, and the sample is prepared using the quartering method. Each test sample of tobacco stem is ≥10.0g, and the test tobacco stem particles are ≥25; Step (3) The measurement steps for the equivalent thickness of the tobacco stem after pressing are as follows: take a sample at the outlet of the pressing machine, place it under constant temperature and humidity conditions of 22℃ and 60% for more than 10 minutes, and along the length of the tobacco stem, at least five measurement points are measured at equal intervals for each tobacco stem. The average value is calculated, which is the equivalent thickness h0 of the tobacco stem after pressing. cs The sample requirements are as follows: a single sample of ≥100g tobacco stems should be taken, and the sample should be prepared using the quartering method. Each test sample of tobacco stems should be ≥10.0g, and the test sample should contain ≥25 tobacco stem particles.

2. The method according to claim 1 is used to evaluate the depressing effect of different depressing machines.

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