Characterization method and use of tobacco stem dilution rate in a dilution mechanism

Abstract

The present invention discloses a method for characterizing the dilution rate of tobacco stems in a dilution mechanism, comprising the following steps: (1) sampling a tobacco stem sample of the dilution mechanism, with a weight m; (2) measuring the projection area of ​​each tobacco stem, and calculating the projection area S of all tobacco stems; (3) calculating the surface density ρ of the tobacco stem sample s :ρ s = m / S; (4) measuring the speed v of the conveyor belt; (5) measuring the effective width w of the conveyor belt; (6) calculating the tobacco stem dilution rate. The present invention also discloses the use of the characterization method for controlling the removal of dark tobacco stems.

Description

Technical Field

[0001] The invention belongs to the technical field of tobacco processing, and in particular relates to a method for characterizing a tobacco stem dilution rate in a dilution mechanism and a method for controlling the removal of dark tobacco stems from tobacco stems. Background Art

[0002] In the tobacco stem pretreatment section of the stem making process of cigarette manufacturing, as the process continues to move backward, the content of dark tobacco stems in the incoming tobacco stems continues to increase, and the color of some dark tobacco stems tends to be black. Before the stem cutting process, the dark tobacco stem content reaches a peak, and the distribution range of dark tobacco stem content in different grades of tobacco stems is 20% to 45%. According to the processing capacity of 3000kg / h of the stem making process, the dark tobacco stem production is 600kg / h to 1350kg / h, and the dark tobacco stem content cannot be ignored.

[0003] The test results show that in addition to the significant difference in the appearance color index of dark tobacco stems, dark tobacco stems also have significant differences in quality indicators such as cell wall materials, conventional chemical components and sensory quality compared with normal appearance color tobacco stems, which has become one of the key factors affecting the quality change of finished stems and is also the bottleneck link restricting the stability of the quality of finished stems. It is also based on this that Patent ZL2015107617859 discloses a tobacco stem grouping processing method based on color discrimination, which can effectively improve the uniformity and stability of stem quality.

[0004] The color distribution in the tobacco stem formula changes from normal color to dark or even black. When using tobacco stem image processing, how to achieve the monolayer and discrete dilution state of tobacco stem particles is one of the key technical links to achieve the identification and accurate separation of dark tobacco stems. Patent ZL2015107617859 has not yet solved the key issues such as quantitative evaluation of the dilution state of tobacco stems and regulation of key parameters of the dilution mechanism, resulting in great limitations and contingency in the identification and removal of dark tobacco stems.

[0005] Image recognition technologies widely used in the cigarette manufacturing process, such as tobacco leaf foreign body removal equipment and tobacco stem foreign body removal equipment, are mostly based on the thinning mechanism (vibration trough, belt) to single-layer and discretize tobacco leaves, tobacco stems and other cigarette raw materials to improve the accuracy of image acquisition, processing and recognition, and then accurately remove foreign bodies and foreign objects in cigarette raw materials. Therefore, how to control the incoming material process flow, establish a dilution mechanism to measure the dilution state of tobacco stems, and optimize the key parameters of the dilution mechanism, have become the key common constraints for solving the purity problem in tobacco stems and tobacco leaves.

[0006] The present invention is proposed for this purpose. Summary of the invention

[0007] In order to improve the image recognition effect of dark tobacco stems and black tobacco stems in normal tobacco stems, and further improve the precise control of the tobacco stem removal process, the present invention discloses a detection and characterization method for the tobacco stem dilution rate.

[0008] The technical solution of the present invention is as follows:

[0009] The first aspect of the present invention discloses a method for characterizing the dilution rate of tobacco stems in a dilution mechanism, comprising the following steps:

[0010] (1) Sampling tobacco stem samples from the dilution mechanism, weight m;

[0011] (2) Pick out all the tobacco stems in the incoming tobacco stem sample of step (1), make the tobacco stems monolayered and discretized, measure the projection area of ​​each tobacco stem in the above tobacco stems by image method, and calculate the projection area S of all tobacco stems according to the following formula:

[0012] (3) Calculate the surface density ρ of the tobacco stem sample according to the following formula s :ρ s =m / S;

[0013] (4) Measure the speed v of the conveyor belt;

[0014] (5) Measure the effective width w of the conveyor belt;

[0015] (6) Calculate the dilution rate of the tobacco stem sample on the dilution device according to the following formula: Where Q is the real-time process flow rate of the tobacco stem sample entering the dilution mechanism, in g / s.

[0016] Preferably, step (1) of sampling the incoming tobacco stem sample of the dilution mechanism comprises: sampling the cross section on the incoming vibration groove of the dilution mechanism, each time taking no less than 100g of tobacco stem sample; preparing the sample by quartering method, the weight of the tobacco stem sample is m and m≥10.00g and the result has an accuracy of 0.01g, and the number of tobacco stem particles is ≥30.

[0017] Preferably, the method for measuring the projection area of ​​tobacco stems by the image method in step (2) is as follows: placing tobacco stem samples in a single layer and discretely on a tobacco stem image acquisition platform, and fixing the tobacco stem samples with a light, transparent pressing sheet; obtaining the projection area S of each tobacco stem i , calculate the projected area S of all tobacco stems, with the result accurate to 0.001m 2 .

[0018] Preferably, the method for measuring the speed v of the conveyor belt in step (4) is: mark the conveyor belt, record the time required for the conveyor belt to run 60 circles, and determine the speed v of the conveyor belt in combination with the length of the conveyor belt, with an accuracy of 0.01 m / s.

[0019] Preferably, the method for measuring the effective width w of the conveyor belt in step (5) is: measuring the distance w between the two side belts of the conveyor belt in the width direction, and the result has an accuracy of 0.01m.

[0020] The second aspect of the present invention discloses the use of the characterization method for controlling the removal of dark tobacco stems.

[0021] Preferably, the tobacco stem dilution rate of the dark tobacco stem removal device is The value is 5.0%~10.0%.

[0022] Beneficial effects of the present invention:

[0023] 1. The characterization method of the present invention, based on the offline detection and quantification of the surface density index of the tobacco stem material, correlates three key parameters such as the tobacco stem process flow rate, belt conveyor line speed, and bandwidth on the tobacco stem foreign matter removal equipment, and constructs a characterization method for the tobacco stem dilution rate. The method of the present invention can scientifically quantify the distribution state and weight distribution of tobacco stems in the dilution mechanism. The method of the present invention has strong technical advantages in the evaluation of the operating conditions and parameter control of foreign matter removal equipment. According to the size of the dilution rate, it can be evaluated whether the operating condition of the dilution mechanism in the foreign matter removal equipment is good, whether the key parameter settings are matched, etc., providing method support for the process maintenance of the foreign matter removal equipment. The characterization method of the present invention can be used to evaluate the tobacco stem dilution effect of different foreign matter removal equipment, and is a quantitative and scientific characterization method for judging the processing effect of tobacco stem foreign matter removal equipment. The quantitative characterization method provided for the dilution effect provides technical method support for the homogenization treatment of tobacco stem incoming materials and the consistency evaluation of the dilution effects of different foreign matter removal equipment.

[0024] 2. The method of the present invention involves few detection parameter indicators. The existing tobacco industry's stem production lines are equipped with online collection functions for the above parameters. The process of collecting or detecting the above parameter indicators is fast and efficient, and the corresponding collection or detection methods are mature, the detection results are highly representative, and the data are accurate and reliable. The parameters involved in the characterization method of the present invention can be automatically collected in the stem production line, and data acquisition is efficient and fast; at the same time, the tobacco stem surface density detection method is static tobacco stem image recognition and weighing, the detection method is mature, the data calculation is convenient, and the process is less time-consuming, so the technology of this patent is highly popularizable.

[0025] 3. The characterization method of the present invention can effectively improve the recognition and removal effect of tobacco stem foreign body removal equipment, and is particularly suitable for the recognition and removal of dark tobacco stems and black tobacco stems. In order to improve the image acquisition quality, recognition effect, and removal accuracy of black tobacco stems, the process maintenance of the material thinning mechanism can be carried out by appropriately increasing the acceleration of the conveyor belt and reducing the process flow of tobacco stems.

[0026] 4. According to the characterization method of the present invention, the tobacco stem dilution rate is an important indicator that affects the effect of foreign matter removal. The smaller the dilution rate, the smaller the image recognition error caused by tobacco stem overlap, the lower the tobacco stem foreign matter judgment process and the false rejection rate caused by the solenoid valve pulse rejection action. The overall performance is that the smaller the dilution rate, the higher the accuracy of foreign matter image recognition and the higher the foreign matter removal effect. At the same time, the smaller the dilution rate, the smaller the material processing capacity of the foreign matter removal equipment. Considering the production capacity matching of stem shreds, it is necessary to reasonably determine the control range of the dilution rate, so as to achieve the joint improvement of the processing capacity and processing effect of the foreign matter removal equipment. According to the characterization method of the present invention, the tobacco stem dilution rate The closer the value is to 0, the better the distribution of tobacco stems is, and the tobacco stem image recognition and removal are in the best state, but the processing capacity of the thinning mechanism is small. The tobacco stem thinning rate of the dark tobacco stem removal device of the present invention is The optimum range is 5.0% to 10.0%. The value is less than 5.0%, the tobacco stems are evenly distributed, and there is no obvious overlap between the tobacco stems. However, the processing capacity of the dilution mechanism is small, which does not match the capacity of the existing stem production line. When the value is greater than 10.0%, the tobacco stems begin to overlap partially, which is not conducive to the collection and recognition of tobacco stem images, accurate algorithm judgment, and accurate removal of tobacco stems by electromagnetic valve pulses. DETAILED DESCRIPTION

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

[0028] Example 1: The steps for determining the dilution rate of the tobacco stem A of the dark tobacco stem removal device for a tobacco stem sample fed by a certain dilution mechanism are as follows: the key parameter settings of the tobacco stem removal device are as follows: the process flow rate is 1500kg / h, the moisture content of the tobacco stem A is 33.5%, the conveyor belt width is 1.25m, and the conveyor belt speed is 3m / s.

[0029] (1) Take samples from the cross section of the dilution mechanism on the vibrating trough, with no less than 100g of tobacco stem sample each time; the sample obtained by sampling is prepared by the quartering method, the weight of the tobacco stem sample is m, and m≥10.00g, the result is accurate to 0.01g, and the number of tobacco stem particles is ≥30;

[0030] (2) Place the tobacco stem samples in a single layer and discretely on the tobacco stem image acquisition platform, and fix the tobacco stem samples with a light, transparent pressing sheet; obtain the projection area S of each tobacco stem i , calculate the projected area S of all tobacco stems, with the result accurate to 0.001m 2 ; Calculate the projected area S of all tobacco stem particles according to the following formula: The result is accurate to 0.001mm 2 ;

[0031] (3) Calculate the surface density ρ of the tobacco stem sample according to the following formula s :ρ s =m / S, the result is accurate to 0.01g / m 2 ;

[0032] Repeat steps (1) to (3) and conduct parallel tests five times. The test results of the five tobacco stem surface densities are shown in Table 1 below.

[0033] Table 1 Test results of tobacco stem surface density

[0034]

[0035] (4) On the stem shred production line, use a conveyor belt speed detector to detect the actual speed v of the conveyor belt when the foreign matter removal device is carrying material; and measure the width of the conveyor belt, which is 1.25m;

[0036] (5) Record the real-time process flow Q of the corresponding tobacco stem foreign matter removal equipment under this condition;

[0037] (6) Calculate the dilution rate of the tobacco stem sample on the dilution device according to the following formula: The test and analysis results of the tobacco stem dilution rate for five times are shown in Table 2 below.

[0038] Table 2 Detection and analysis results of tobacco stem dilution rate

[0039]

[0040] Under the key parameter setting conditions of the above tobacco stem foreign body removal equipment, the tobacco stem dilution rate on the belt conveyor is 4.68%. According to the requirements of the value, the processing capacity of this foreign matter removal equipment still has room for further improvement. When only considering the dilution rate indicator, the processing capacity of this foreign matter removal equipment can be increased to 1800kg / h and above, and the corresponding tobacco stem dilution rate is 5.58% and above.

[0041] Example 2: Effect of adjustment of key parameters on the dark tobacco stem removal rate of the tobacco stem foreign body removal device for incoming tobacco stem sample B when removing dark tobacco stems.

[0042] The key parameters of the dark tobacco stem removal equipment are as follows: process flow rate is 1200kg / h, moisture content of tobacco stem B is 33.5%, and conveyor belt width is 1.05m. The dark tobacco stem content in tobacco stem sample B obtained by manual sorting is 28.4%.

[0043] The tobacco stem surface density was 2267.97 g / m 2, conveyor belt width 1.05m. Thinning rate of tobacco stems on the thinning device The detection and analysis results of the tobacco stem dilution rate for five times are shown in Table 3 below.

[0044] Table 3 Detection and analysis results of tobacco stem dilution rate

[0045]

[0046] The weight of the dark tobacco stems collected after being rejected by the foreign body rejection machine of this embodiment is 530.05kg; the total amount of incoming tobacco stem sample B is 1563.4kg, and the actual rejection rate of dark tobacco stems is calculated to be 33.90%, which is higher than the 28.4% content of dark tobacco stems sorted manually. This phenomenon shows that the rejection rate is too high after the tobacco stem dilution rate is higher than 10%, which may be caused by different degrees of overlap or misrecognition in the tobacco stem image acquisition and image recognition process. Checking the dark tobacco stems rejected in this embodiment, there are a certain amount of normal color tobacco stems. This further proves that under the parameter setting conditions, the tobacco stem dilution rate is controlled to be too high, which is not conducive to the accurate removal of dark tobacco stems in the tobacco stems. At this time, the tobacco stem thinning rate can be quickly reduced by adjusting the running speed of the conveyor belt. For example, when the running speed of the conveyor belt is increased to 1.60m / s, the tobacco stem thinning rate on the thinning mechanism is reduced to 8.75%. At this time, the corresponding dark tobacco stem rejection rate is 29.11%, which is close to the dark tobacco stem content of 28.4% in manual sorting. The content of normal color tobacco stems in the rejected dark tobacco stems is small and the number of false rejections is low.

[0047] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for characterizing the dilution rate of tobacco stems in a dilution mechanism, characterized in that: The steps include: (1) Sampling the incoming tobacco stem sample of the dilution mechanism, with a weight of m; the sampling steps are: sampling the cross section on the incoming vibration groove of the dilution mechanism, with no less than 100g of tobacco stem sample each time; the sampled sample is prepared by the quartering method, the weight of the tobacco stem sample is m, and m≥10.00g, the result is accurate to 0.01g, and the number of tobacco stem particles is ≥30; (2) Pick out all the tobacco stems in the incoming tobacco stem sample of step (1), make the tobacco stems monolayered and discretized, measure the projection area of ​​each tobacco stem in the above tobacco stems by image method, and calculate the projection area S of all tobacco stems according to the following formula: The projection area method is as follows: place the tobacco stem samples in a single layer and discretely on the tobacco stem image acquisition platform, and use a light, transparent pressing sheet to fix the tobacco stem samples; obtain the projection area S of each tobacco stem i , calculate the projected area S of all tobacco stems, with the result accurate to 0.001m 2 ; (3) Calculate the surface density ρ of the tobacco stem sample according to the following formula s :ρ s =m / S; (4) Measure the speed v of the conveyor belt. The speed v of the conveyor belt is measured by making a mark on the conveyor belt, recording the time required for the conveyor belt to run 60 circles, and determining the speed v of the conveyor belt based on the length of the conveyor belt. The result has an accuracy of 0.01 m / s. (5) Measure the effective width w of the conveyor belt. The effective width w of the conveyor belt is measured by measuring the distance w between the two side belts in the width direction of the conveyor belt. The result has an accuracy of 0.01 m. (6) Calculate the dilution rate of the tobacco stem sample on the dilution device according to the following formula: Where Q is the real-time process flow rate of the tobacco stem sample entering the dilution mechanism, in g / s.

2. Use of the characterization method according to claim 1 for controlling the removal of dark tobacco stems.

3. The use according to claim 2, characterized in that: Tobacco stem thinning rate of dark stem rejection equipment The value is 5.0%~10.0%.

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