Method for automatically adjusting the discharge frequency of an electronic belt scale feed bin

Abstract

The application discloses a kind of methods for automatically adjusting and controlling the discharge frequency of electronic belt scale feed storage tank, comprising: (1) calculating the filling redundancy time T3 of limit tube = limit tube discharge time T2-limit tube filling time T1;(2) the belt running distance in limit tube filling time is calculated as B2=S1×T1, S1 is the linear speed of belt conveyor;The ratio M of the belt running distance of the belt conveyor of the discharge port of storage tank and the length of discharge port belt is calculated as B2 / B1, B1 is the length of discharge port belt of storage tank;(3) the redundancy S2 of storage tank discharge in unit filling time is calculated as P1 / T1, P1 is the set frequency of storage tank bottom belt discharge;(4) the redundancy P2 of storage tank discharge is calculated as S2×T3;(5) the best discharge frequency P3 of storage tank is calculated as P1-P2×|(1-M)|, and the control program automatically executes the best discharge frequency.The application can adjust the discharge frequency of electronic belt scale feed storage tank, avoid the phenomenon of fast and slow feeding speed, frequent start and stop of electronic belt scale feeding end equipment or large instantaneous flow fluctuation of material, etc.

Description

Technical Field

[0001] This invention belongs to the field of cigarette manufacturing technology, specifically, it relates to a method for automatically adjusting the frequency of the feed end storage tank motor to match the process flow of a control-type electronic belt scale. Background Technology

[0002] Electronic belt scales (hereinafter referred to as electronic belt scales) are used in various processes on cigarette manufacturing lines, including feeding, flavoring, and tobacco blending. These scales ensure stable material flow at a set rate. The feeding of the electronic belt scales is handled by storage tanks, and the discharge rate of these tanks determines whether the electronic belt scales can achieve stable flow control. During production, operators adjust the tanks based on experience and the amount of material stored. To prevent flow fluctuations due to insufficient supply, operators often set the tank discharge frequency relatively high, which can lead to frequent start-ups and shutdowns of related equipment at the feed end of the electronic belt scale, and even blockages at the tank discharge port or the feed inlet of the electronic belt scale. Therefore, automatically and accurately adjusting the tank discharge frequency would effectively reduce equipment start-ups and shutdowns and prevent blockages. Currently, there are no reports in the domestic tobacco industry regarding methods for automatically adjusting the tank discharge frequency; therefore, it is necessary to adopt new methods to solve the problem of matching the electronic belt scale's feeding performance.

[0003] See Figure 1 As shown, the material feeding method of the electronic belt scale is as follows: the material in the storage tank 2 falls from the discharge port 3, and the material is conveyed to the electronic belt scale feeding belt 5 via the discharge port belt 4. The material then falls naturally into the electronic belt scale limiting tube 10 via the upper feed bin 6. If the photoelectric tube 8 in the feed bin detects the material for a certain period of time, it will issue a material blockage alarm. The material feeding amount in the electronic belt scale limiting tube is controlled by the signals of the high material level photoelectric tube 9 and the low material level photoelectric tube 11. When the material level reaches the high material level photoelectric tube 9, the equipment at the feeding end will temporarily stop running. When the material level is lower than the low material level photoelectric tube 11, the equipment at the feeding end will resume running. After the material falls onto the surface 13 of the electronic belt scale, it moves with the running direction of the belt. After being shaped and pressed by the shaping roller 14, the material runs to the belt scale discharge port 15 to enter the next process.

[0004] CN115303818A discloses a flow control system for preventing material blockage in a wire-making line. The system uses a controller to adjust the conveyor belt speed, and a material monitoring device performs a second monitoring of the material in the metering tube. Based on the second monitoring result, the controller adjusts the conveyor belt to prevent blockage caused by a large influx of material into the metering tube's funnel-shaped inlet and delayed discharge. However, this method lacks the ability to coordinate the discharge speed of the storage tank with the flow rate requirements of the electronic belt scale.

[0005] The paper "Analysis and Control of Operational Stability and Metering Reliability of Electronic Belt Scales" (Sun Lu et al., Metrology Science and Technology, 2018, No. 2) improved the control method of material level control in the limiting tube of electronic belt scales by replacing photocells with gratings, improving the structure of the baffles on both sides of the electronic belt scale, and using wedge-shaped baffles to eliminate the squeezing phenomenon. Ultimately, under the operating condition of a set flow rate of 2000 kg / h, the actual material flow fluctuation range was improved from ±10 kg / h to ±4 kg / h. Although this study achieved accurate detection of the material height in the storage tank and alleviated the material squeezing problem on the belt scale, it failed to achieve accurate control of the discharge speed from the storage tank.

[0006] CN110663330A discloses a crop fertilization device that adjusts the discharge rate by controlling the opening and closing frequency. It uses a gear transmission principle to control the movement of a moving rod and achieves baffle position control, thereby regulating the discharge rate. This invention controls the material quantity by adjusting the size of the discharge port and does not involve the field of electronic belt scale feed flow control.

[0007] The article "The Influence of Discharge Speed ​​on Tobacco Structure and Cigarette Quality" (Tian Qiusheng et al., Science & Technology Information, 2011, No. 27) tested and analyzed the effects of different discharge speeds of the tobacco storage cabinet on cigarette quality. The results showed that excessively fast or slow discharge speeds easily lead to a decrease in tobacco quality. Within the experimental range, the tobacco quality was best when the discharge speed of the storage cabinet was 19.6 m / h. This study determined the optimal discharge speed for the tobacco storage cabinet and did not address the issue of feed flow control using electronic belt scales.

[0008] The article "Research on Tank Discharge Speed ​​Based on Grating Control" (Lai Lin et al., Automation Application, No. 10, 2018) compares traditional tank discharge control methods with the MINI ARRARY grating detection system, which monitors material height changes in real time during tank discharge and adjusts the tank bottom belt frequency accordingly to ensure stable material flow throughout the production process. While this research considers the material quantity in the tank and controls the discharge frequency based on grating detection results, it is limited to tank discharge control and does not correlate with the flow rate of the electronic belt scale.

[0009] "Application of Minimum Load in Electronic Belt Scale Control" (Zhuo Yue, Master's Thesis, Xiamen University, June 2009) introduces a "minimum load" concept to control the initial stage of production, based on the improved PLC control program of the blending zone. This method pre-loads each electronic belt scale with a minimum load to address the severe shortage of blending materials at the beginning of tobacco blending (i.e., the initial material stage). The core of this research is solving the material defect problem at the initial material stage of the belt scale, falling within the research field of material blending accuracy.

[0010] CN219602526U discloses a material feeding and shaping device and a material distribution and guiding device for a tobacco flavoring machine. To address the problem of unstable material flow into the flavoring machine and the breakage of tobacco shreds due to large drop heights, a material feeding and shaping unit was designed and installed connecting the electronic belt scale and the feeding belt conveyor. This unit uses feeding rollers to evenly distribute and shape the tobacco shreds, ensuring they are uniformly and evenly distributed within the belt conveyor for transport. While this research solves the problem of flow stability in the belt scale's feed hopper, it does not further investigate the flow rate of the feeding end equipment. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to overcome the above-mentioned deficiencies and provide a method for automatically adjusting the discharge frequency of the feeding tank of an electronic belt scale.

[0012] The control elements and related variables involved in this invention include: the set flow rate L (kg / h) of the electronic belt scale; the filling time T1 (seconds) of the electronic belt scale limit tube; the discharge time T2 (seconds) of the electronic belt scale limit tube; the filling redundancy time T3 (seconds) of the electronic belt scale limit tube; the belt length B1 (meters) at the discharge port of the storage tank; the belt running distance B2 (meters) at the discharge port of the storage tank; the belt linear speed S1 (meters / second) at the discharge port of the storage tank; and the discharge redundancy S2 (times / second) of the storage tank within a unit filling time. 2 The ratio M of the belt running distance to the belt length at the discharge port of the storage tank; the set discharge frequency P1 (times / second); the storage tank redundancy P2 (times / second); the optimal discharge frequency of the storage tank is P3 (times / second). The method for controlling the discharge frequency of the storage tank is as follows:

[0013] 1. Given that the set flow rate L (kg / h) of the electronic belt scale is larger, the material supply will be greater.

[0014] 2. Calculate the filling time T1 of the electronic belt scale limit tube based on the signal time of the high and low material level detection phototubes. T1 = closing time of the high material level detection phototube (phototube signal is 1) - opening time of the low material level phototube (phototube signal is 0).

[0015] 3. Calculate the discharge time T2 of the electronic belt scale limit tube based on the signal time of the high and low material level detection phototubes. T2 = the time when the low material level phototube is switched off (phototube signal is 0) - the time when the high material level detection phototube is switched off (phototube signal is 0).

[0016] 4. The waiting time for feeding through the limit tube of the electronic belt scale is the filling redundancy time T3 of the limit tube of the electronic belt scale, where T3 = T2 - T1;

[0017] 5. Given that the length of the conveyor belt at the discharge port of the storage tank is B1 (meters) and the linear speed of the conveyor belt is S1 (meters / second), first calculate the distance the conveyor belt travels during the filling time of the electronic belt scale's limiting tube as B2 (meters), B2 = S1 × T1. Then calculate the ratio M of the distance the conveyor belt travels at the discharge port of the storage tank to the length of the discharge port belt, M = B2 / B1.

[0018] 6. Given the set discharge frequency P1 (times / second) of the bottom belt conveyor of the storage tank, since a larger filling time T1 of the electronic belt scale's limiting tube indicates a relatively slower discharge frequency, and vice versa, calculate the storage tank discharge redundancy S2 (times / second) per unit filling time of the limiting tube. 2 S2 = P1 / T1;

[0019] 7. Calculate the storage tank discharge redundancy P2 based on the unit time discharge redundancy S2 and the electronic belt scale limit tube filling redundancy time T3. P2 = S2 × T3.

[0020] 8. Finally, based on the storage tank discharge redundancy P2, the storage tank bottom belt discharge setting frequency P1, and the ratio M of the belt running distance of the storage tank discharge port belt conveyor to the length of the discharge port belt, the optimal discharge frequency P3 of the storage tank is calculated, P3 = P1 - P2 × |(1-M)| (where |(1-M)| represents the absolute value of the logarithmic value (1-M),) and the control program automatically executes the optimal discharge frequency.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention can accurately adjust the discharge frequency of the electronic belt scale's feeding tank, avoiding frequent start-ups and shutdowns of the electronic belt scale's feeding end equipment or large fluctuations in the instantaneous flow rate of materials caused by varying feeding speeds. Attached Figure Description

[0023] Figure 1 Layout diagram of a controlled electronic belt scale feeding device. Detailed Implementation

[0024] Example 1

[0025] During the tobacco flavoring production process in the factory, it was found that the filling time of the electronic belt scale's limiting tube was significantly longer than the discharging time. This slow feeding speed caused large fluctuations in the instantaneous flow rate of the material. The method used accurately adjusted the discharging frequency of the electronic belt scale's feeding tank. The system's automatic adjustment process is as follows:

[0026] The system identifies that the set flow rate L of the electronic belt scale before blade feeding is 8000 kg / h. Based on the high and low material level photocell detection signals of the electronic belt scale's limit tube, the system calculates the filling time T1 of the limit tube to be 19 seconds and the discharge time T2 to be 13 seconds. Simultaneously, it calculates the filling redundancy time T3 to be -6 seconds. Given that the belt length B1 of the conveyor belt at the tank discharge port is 2.5 meters and the conveyor linear speed S1 is 0.18 m / s, the system first calculates the belt travel distance B2 to be 3.42 meters during the filling time of the electronic belt scale's limit tube, and then calculates the ratio M of the belt travel distance to the belt length at the tank discharge port to be 1.37. The current set discharge frequency P1 of the tank bottom belt is 35 times / second. Based on the filling time T1 of the electronic belt scale's limit tube, the tank discharge redundancy S2 per unit time is calculated to be 1.84 times / second. 2 Based on the storage tank discharge redundancy S2 per unit time and the electronic belt scale limit tube filling redundancy time T3, the storage tank discharge redundancy P2 is calculated to be -11.1 times / second; then based on the storage tank discharge redundancy P2, the storage tank bottom belt discharge setting frequency P1, and the ratio M of the belt running distance of the storage tank discharge port belt conveyor to the length of the discharge port belt, the optimal discharge frequency P3 of the storage tank is finally calculated to be 39 times / second.

[0027] Example 2

[0028] During the blade feeding production process at the factory, it was found that the filling time of the limit tube of the electronic belt scale was significantly shorter than the discharging time. The fast feeding speed caused frequent start-ups and shutdowns of the equipment at the feeding end of the electronic belt scale. This method was used to quickly and accurately adjust the discharging frequency of the electronic belt scale's feeding tank. The automatic adjustment process of the system is as follows:

[0029] The system identifies that the set flow rate L of the electronic belt scale before blade feeding is 6000 kg / h. Based on the high and low material level photocell detection signals of the electronic belt scale's limit tube, the system calculates the filling time T1 of the electronic belt scale's limit tube as 10 seconds and the discharge time T2 as 15 seconds, while also calculating the filling redundancy time T3 as 5 seconds. Given that the belt length B1 of the conveyor belt at the tank discharge port is 2 meters and the conveyor linear speed S1 is 0.15 m / s, the system first calculates the belt travel distance B2 of 1.5 meters during the electronic belt scale's limit tube filling time, and then calculates the ratio M of the belt travel distance to the discharge port belt length as 0.75. The current set frequency P1 for bottom belt discharge from the tank is 38 Hz. Based on the electronic belt scale's limit tube filling time T1, the tank discharge redundancy S2 is calculated to be 3.8 times / second. 2Based on the storage tank discharge redundancy S2 per unit time and the electronic belt scale limit tube filling redundancy time T3, the storage tank discharge redundancy P2 is calculated to be 19 times / second; then based on the storage tank discharge redundancy P2, the storage tank bottom belt discharge set frequency P1, and the ratio M of the belt running distance of the storage tank discharge port belt conveyor to the length of the discharge port belt, the optimal discharge frequency P3 of the storage tank is finally calculated to be 33 times / second.

Claims

1. A method for automatically adjusting the discharge frequency of a feeding storage tank in an electronic belt scale, wherein the electronic belt scale is equipped with a limit tube, and a high / low material level photocell is installed in the limit tube, the high / low material level photocell being used to sense high / low material level signals, characterized in that... The method comprises the following steps: Step 1, calculating the electronic belt scale limit tube filling redundancy time T3=T2-T1, wherein: T1 is the electronic belt scale limit tube filling time, T2 is the electronic belt scale limit tube discharging time; the electronic belt scale limit tube filling time T1=high material level detection photocell closing time-low material level photocell opening time; the electronic belt scale limit tube discharging time T2=low material level photocell opening time-high material level detection photocell opening time; Step 2, calculating the belt running distance of the belt conveyor in the electronic belt scale limit tube filling time as B2=S1*T1, wherein S1 is the linear speed of the belt conveyor; calculating the ratio M of the belt running distance of the belt conveyor at the discharge port of the storage cabinet to the length of the belt at the discharge port as B2 / B1, wherein B1 is the length of the belt at the discharge port of the storage cabinet; Step 3, calculating the redundancy S2 of the discharge of the storage cabinet per unit filling time as P1 / T1, wherein P1 is the set frequency of the discharge of the bottom belt of the storage cabinet; Step 4, calculating the redundancy P2 of the discharge of the storage cabinet as S2*T3; Step 5, calculating the optimal discharge frequency P3 of the storage cabinet as P1-P2*|(1-M)|, and automatically executing the optimal discharge frequency by the control program, wherein: M is the ratio of the belt running distance of the belt conveyor at the discharge port of the storage cabinet to the length of the belt at the discharge port, and |(1-M)| represents taking the absolute value of the logarithmic value (1-M).

2. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by a processor to implement the steps of the method for automatically adjusting and controlling the discharge frequency of the electronic belt scale feeding storage cabinet according to claim 1.

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