Material conveying control method, electronic equipment and material conveying system

Abstract

The invention belongs to the technical field of industrial control, and discloses a material conveying control method, electronic equipment and a material conveying system.The material conveying control method comprises the steps that the first rotating speed of a servo motor is calculated according to the given discharging speed, the size of material distributing grooves in material distributing equipment, the number of the material distributing grooves in the material distributing equipment and the material density; in the material conveying process, the first weight of the metering bin is measured in real time, and the actual discharging weight and the actual discharging speed are calculated according to the first weight and the second weight at the preset historical moment; based on the given blanking speed and the time difference between the current moment and the preset historical moment, the theoretical blanking weight is calculated; and when the difference value between the actual discharging weight and the theoretical discharging weight exceeds the preset range, the second rotating speed of the servo motor is determined according to the actual discharging speed, the given discharging speed and the actual rotating speed of the servo motor till material conveying is completed. The conveying precision can be improved, and quantitative conveying of materials is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of pneumatic material transportation, and in particular relates to a material transportation control method, electronic equipment and a material transportation system. Background Art

[0002] At present, pneumatic conveying technology is mainly used for feeding powder or granular materials. The powder or granular materials in the metering silo are fed to the pneumatic conveying component (such as a pneumatic pipeline conveyor) through the material distribution equipment (such as a rotary material distribution valve or a screw conveyor). The pneumatic conveying component uses compressed air to transport the powder or granular materials through the pipeline. It is widely used in many fields such as chemical industry, environmental protection, and building materials. Among them, the material distribution equipment plays the role of quantitative feeding, and the weighing system is installed on the metering silo to detect the weight of the material transported per unit time.

[0003] However, all the distributing equipment have the following problems: the problem of filling rate, that is, the weight of the material falling into the valve slot of the rotary distributing valve or the spiral slot of the screw conveyor (the valve slot and the spiral slot are collectively referred to as the distributing slot) each time is not fixed. Sometimes it is full, and sometimes it is not. This leads to inaccurate material conveying volume per unit time; the gap of the sealing ring of the discharge port is prone to accumulation of materials, affecting the conveying accuracy; due to positive pressure conveying, the material is easy to fall quickly through the gap of the distributing equipment at high speed, affecting the conveying accuracy of the distributing equipment.

[0004] Therefore, during the current material transportation, it is difficult for the material distribution equipment to quantitatively and accurately transport the materials to the pneumatic conveying components, and the conveying accuracy needs to be improved. Summary of the invention

[0005] The object of the present invention is to provide a material conveying control method, electronic equipment and a material conveying system, which can improve the material conveying accuracy.

[0006] The first aspect of the present invention discloses a material conveying control method, comprising: Calculate a first rotation speed of a servo motor according to a given material unloading speed, a volume of a material distribution trough in the material distribution device, a number of material distribution troughs in the material distribution device, and a material density, wherein the servo motor is used to drive the material distribution device to rotate, and the material distribution device is provided with a plurality of material distribution troughs along a circumferential direction; During the material conveying process, the first weight of the metering silo is measured in real time, and the actual unloading weight and the actual unloading speed are calculated based on the first weight and the second weight at a preset historical moment; the theoretical unloading weight is calculated based on a given unloading speed and the time difference between the current moment and the preset historical moment; when the difference between the actual unloading weight and the theoretical unloading weight exceeds a preset range, the second speed of the servo motor is determined based on the actual unloading speed, the given unloading speed and the actual speed of the servo motor until the material conveying is completed.

[0007] In some embodiments, the material dispensing device is a rotary dispensing valve, the valve core of the rotary dispensing valve has valve teeth, and two adjacent valve teeth surround the dispensing trough. The material conveying process also includes: Calculate the material discharge time of the material distribution trough according to the tooth height of the valve teeth; Calculate the maximum speed of the servo motor according to the material unloading time and the angle of the material distribution trough in the circumferential direction; When the first rotational speed or the second rotational speed exceeds the maximum rotational speed, a warning signal is sent.

[0008] In some embodiments, determining the second speed of the servo motor according to the actual material feeding speed, the given material feeding speed and the actual speed of the servo motor includes: Calculating the ratio of the given material feeding speed to the actual material feeding speed; The product of the ratio and the actual rotation speed is calculated to obtain the second rotation speed.

[0009] In some embodiments, the material dispensing equipment is a rotary dispensing valve, which has a valve core and a shell, and there is a gap between the valve core and the inner wall of the shell. When the rotary dispensing valve rotates, air is blown to the discharge port of the metering silo through the first air supply valve, so that the material accumulated in the gap is blown back to the discharge port, and the material at the discharge port is broken, and / or, air is blown to the discharge port of the metering silo through the second air supply valve to break the arch of the material at the discharge port, and the blowing direction of the second air supply valve and the blowing direction of the first air supply valve are staggered.

[0010] In some embodiments, the valve core is provided with valve teeth, and when the rotary dispensing valve rotates, the material accumulated in the gap is scraped off by the scraper plates on the valve teeth.

[0011] A second aspect of the present invention discloses a material conveying system, comprising: A metering silo, a weighing device, a material distribution equipment, a pneumatic conveying component, a control device, a servo motor, and a receiving silo. The metering silo is used for temporarily storing materials. The weighing device is used to weigh the materials in the metering silo. The inlet of the material distribution equipment is connected to the metering silo, the outlet of the material distribution equipment is connected to the pneumatic conveying component, the outlet of the pneumatic conveying component is connected to the receiving silo, the servo motor is electrically connected to the material distribution equipment, the control device is electrically connected to the servo motor, and any one of the above-mentioned material conveying control methods is run on the control device.

[0012] In some embodiments, it also includes a frame and a conveying pipeline, the discharge port of the pneumatic conveying component is connected to a hose, the hose is fixed on the frame, the first end of the conveying pipeline is connected to the hose, and the second end of the conveying pipeline is connected to the receiving silo.

[0013] In some embodiments, the material distribution equipment is a rotary material distribution valve, and the rotary material distribution valve is provided with a first air supply valve and a second air supply valve. The first air supply valve and the second air supply valve are arranged adjacent to the inlet of the rotary material distribution valve, and the blowing direction of the first air supply valve and the blowing direction of the second air supply valve are staggered.

[0014] In some embodiments, the rotary dispensing valve has a valve core, on which a plurality of valve teeth are distributed circumferentially, and a plurality of scraper plates are provided, wherein the scraper plates are installed at the top of the valve teeth and the plurality of scraper plates are distributed at intervals on the plurality of valve teeth, and the scraper plates are made of flexible material.

[0015] In some embodiments, a material baffle plate is obliquely installed in the rotary dispensing valve, and the feed port of the rotary dispensing valve is divided into a feed chamber and a material baffle chamber by the material baffle plate. An anti-stuck block is fixed in the material baffle chamber, and the anti-stuck block has a plurality of tooth-shaped protrusions, and both sides of the protrusion are inclined surfaces, and the inclined surfaces are arranged obliquely downward from the top of the protrusion to both sides of the protrusion. The bottom of the anti-stuck block is provided with an arc-shaped surface, and an avoidance portion is provided at the position where the arc-shaped surface intersects with the root of the protrusion.

[0016] The beneficial effects of the present invention are: The material conveying control method and material conveying system of the present invention compensate for the filling rate of the material distribution equipment by intelligently controlling the rotation speed of the servo motor, accurately control the conveying speed through closed-loop control, correct the error of the conveying weight online, improve the conveying accuracy, and realize the quantitative conveying of materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings herein show specific examples of the technical solutions described in the present invention, and together with the specific implementation methods constitute a part of the specification, and are used to explain the technical solutions, principles and effects of the present invention.

[0018] Unless otherwise specified or defined, the same reference numerals in different drawings represent the same or similar technical features, and the same or similar technical features may also be represented by different reference numerals.

[0019] Figure 1 is a three-dimensional diagram of a material conveying system disclosed in an embodiment of the present invention; Figure 2 It is a three-dimensional diagram of a rotary distributor valve in a material conveying system; Figure 3 It is a cross-sectional view of a rotary distributor valve in a material conveying system; Figure 4 It is a three-dimensional diagram of the anti-stuck block in the material conveying system; Figure 5 It is a flow chart of a material conveying control method disclosed in an embodiment of the present invention.

[0020] Description of reference numerals: 100, quantitative conveying component, 110, metering silo, 120, weighing device, 130, material distribution equipment, 140, pneumatic conveying component, 150, control device, 160, servo motor, 170, first frame, 200, receiving assembly, 210, receiving silo, 220, second rack, 300, pipeline, 400, rotary dispensing valve, 410, valve core, 411, valve slot, 412, valve teeth, 420, housing, 430, first air supply valve, 440, second air supply valve, 450, scraper plate, 460, baffle plate, 470, feed chamber, 480, baffle chamber, 490, anti-stuck block, 491, protrusion, 492, arc surface, 493, avoidance portion. DETAILED DESCRIPTION

[0021] Unless otherwise specified or defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art. In combination with the technical solution of the present invention in a realistic scenario, all technical and scientific terms used herein may also have meanings corresponding to the purpose of implementing the technical solution of the present invention. The "first, second..." used herein is only used to distinguish the names and does not represent a specific quantity or order. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0022] It should be noted that when a component is considered to be "fixed to" another component, it can be directly fixed to the other component or there can be a central component; when an component is considered to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time; when an component is considered to be "installed on" another component, it can be directly installed on the other component or there can be a central component at the same time. When an component is considered to be "set on" another component, it can be directly set on the other component or there can be a central component at the same time.

[0023] Unless otherwise specified or defined, the "said" and "the" used in this document refer to the technical features or technical contents mentioned or described before the corresponding position, and the technical features or technical contents may be the same as or similar to the technical features or technical contents mentioned therein. In addition, the terms "including" and "having" and any variations thereof used in this document are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0024] When using pneumatic conveying technology to transport powder or granular materials, although the metering silo is currently weighed at regular intervals, due to the influence of many factors, it is still difficult to achieve quantitative and accurate delivery of materials to the pneumatic conveying components per unit time, and the conveying accuracy still needs to be improved.

[0025] In order to improve the conveying accuracy, the present invention, on the one hand, improves the structure of the existing material conveying system, and on the other hand, adopts closed-loop control in the material conveying process to perform real-time compensation on the servo motor controlling the material distribution equipment, thereby realizing quantitative conveying of materials.

[0026] Specifically, Figure 1 As shown, this embodiment provides a material conveying system for conveying powder. It includes a quantitative conveying component 100 and a receiving component 200, and the quantitative conveying component 100 and the receiving component 200 are connected by a conveying pipeline 300. The quantitative conveying component 100 conveys the material to the receiving component 200 in a quantitative manner within a unit time. The quantitative conveying component 100 mainly includes a metering silo 110, a weighing device 120, a material distribution device 130, a pneumatic conveying component 140, a control device 150 and a servo motor 160. The quantitative conveying component 100 is fixed on the first frame 170; the receiving component 200 mainly includes a receiving silo 210, which is fixed on the second frame 220. Among them, powder is stored in the metering silo 110, and the lower part of the metering silo 110 is a discharge port, and the upper part is a feed port. A weighing device 120 is installed on the metering silo 110 to weigh the powder in the metering silo 110. The discharge port of the metering silo 110 is connected to the feed port of the material distribution device 130, and the discharge port of the material distribution device 130 is connected to the pneumatic conveying component 140. The material distribution device 130 is commonly a rotary material distribution valve or a screw conveyor. Figure 2 and Figure 3As shown, the present embodiment is a rotary dispensing valve 400, and a plurality of valve grooves 411 are distributed circumferentially on the valve core 410 of the rotary dispensing valve 400. When the rotary dispensing valve 400 rotates, the powder in the valve groove 411 is discharged one by one at the outlet of the rotary dispensing valve 400, and conveyed to the inlet of the pneumatic conveying component 140. Each valve groove 411 is a dispensing groove. Similarly, if the dispensing equipment is a screw conveyor, a spiral groove is provided circumferentially on the screw conveyor, and each spiral groove can accommodate powder, and the spiral groove is equivalent to a dispensing groove.

[0027] The discharge port of the pneumatic conveying assembly 140 is connected to the receiving silo 210 through the conveying pipeline 300. The servo motor 160 is electrically connected to the material distribution device 130 to control the rotation speed of the material distribution device 130. It is preferred to use a servo motor instead of an ordinary motor, which can more conveniently realize the closed-loop control of powder material transportation. The control device 150 is electrically connected to the servo motor 160, and an electronic terminal with a touch screen (not shown in the figure) can also be installed on the first frame 170. A given material discharge speed can be input through the touch screen, and various parameters of the equipment in the conveying system can be displayed on the touch screen. The conveying amount can also be graphically displayed, such as displaying a material discharge curve according to the conveying amount and time. A material conveying control method is run on the control device 150, and a control signal is sent to the servo motor 160 according to the relevant parameters input on the touch screen, so as to control the position, speed and torque of the material distribution device 130, and in the process of material transportation, the rotation speed of the servo motor 160 can be controlled in real time, and the deviation occurring during the conveying process can be corrected in time to improve the conveying accuracy.

[0028] Since the pneumatic conveying assembly 140 conveys powder to the receiving silo 210 through the conveying pipe 300, the weight of the material conveyed each time is different due to the air pressure or the fact that the fullness of the material distribution trough is not 100%. During the conveying process, the conveying pipe 300 will fluctuate, generating a pulling force on the pneumatic conveying assembly 140, dragging the pneumatic conveying assembly 140. The pneumatic conveying assembly 140 is connected to the rotary material distribution valve 400, and the rotary material distribution valve 400 is connected to the metering silo 110. Therefore, when the pneumatic conveying assembly 140 is dragged, the metering silo 110 may vibrate slightly, affecting the weighing accuracy. In order to avoid this situation, in this embodiment, a hose is added between the pneumatic conveying assembly 140 and the conveying pipe 300, the discharge port of the pneumatic conveying assembly 140 is connected to the hose, the first end of the conveying pipe 300 is connected to the hose, the second end of the conveying pipe 300 is connected to the receiving silo 210, and the hose is fixed on the first frame 170. By docking the conveying pipeline 300 with the hose, and fixing the hose on the first frame 170, when the conveying pipeline 300 fluctuates, the pulling force is transmitted to the first frame 170, and will not drag the pneumatic conveying component 140, nor will it affect the weighing accuracy, thereby improving the conveying accuracy by ensuring the metering accuracy.

[0029] refer to Figure 2 and Figure 3 , the rotary dispensing valve 400 has a valve core 410 and a shell 420, and there is a gap between the valve core 410 and the inner wall of the shell 420. Powder may accumulate in these gaps, which may affect the rotation of the rotary dispensing valve 400 on the one hand and reduce the actual rotation speed; on the other hand, it also causes the weight of the material discharged by the weighing device to be inconsistent with the weight actually delivered to the pneumatic conveying component. For example, the weight of the material discharged by the weighing device is Xkg, but the weight actually delivered to the pneumatic conveying component will be less than Xkg, affecting the discharge accuracy. Therefore, in this embodiment, a first air supply valve 430 and a second air supply valve 440 are installed near the feed inlet of the rotary dispensing valve 400. Specifically, there are two first air supply valves 430, which are installed on the left and right sides of the rotary dispensing valve 400. In the air flow blown out by the first air supply valve 430, a part of the air flow blows the material accumulated in the gap back to the discharge port of the metering silo 110, and another part of the air flow flows upward, which plays a certain arch-breaking role on the discharge port of the metering silo 110. The second air supply valve 440 is arranged at the front side and / or the rear side of the rotary material distribution valve 400, and the blowing direction of the first air supply valve 430 and the blowing direction of the second air supply valve 440 are staggered, and the air flow blown by the second air supply valve 440 can enhance the arch breaking effect, activate the powder material, and prevent the material from piling up. Therefore, the first air supply valve 430 and the second air supply valve 440 can play a sealing role on the one hand, and prevent the material from piling up in the gap to a certain extent, and on the other hand, can improve the slot fullness rate of the material distribution slot.

[0030] The first air supply valve 430 and the second air supply valve 440 can blow away the powder near the discharge port of the metering silo 110, but powder may still accumulate in the gap between the valve core 410 and the shell 420 of the rotary dispensing valve 400. Therefore, a plurality of scraper plates 450 are also installed in this embodiment. Specifically, a plurality of valve teeth 412 are distributed circumferentially on the valve core 410, and the scraper plates 450 are installed at the top of the valve teeth 412. Four scraper plates 450 are installed and installed at intervals on the plurality of valve teeth 412. The scraper plates 450 are made of a flexible material, such as a silicone scraper. The height requirement of the scraper plates 450 protruding from the valve teeth 412 satisfies that the gap between the scraper plates 450 and the inner wall of the shell 420 allows air to pass but does not pass material. By setting up the scraper plate 450, on the one hand, it can play a sealing role to prevent part of the powder from falling quickly through the gap between the valve core 410 and the inner wall of the shell 420 when the powder falls under pressure, and the accuracy of quantitative delivery cannot be guaranteed; on the other hand, it can also scrape off the powder in the gap to improve the delivery accuracy.

[0031] In this embodiment, only the ends of four valve teeth 412 are selected to be embedded with silicone scrapers. The reason why all valve teeth 412 are not considered to be embedded with silicone scrapers is that if too many valve teeth are equipped with silicone scrapers, the rotation friction of the rotary dispensing valve 400 will increase, affecting the rotation of the rotary dispensing valve 400. On the contrary, if too few valve teeth are equipped with silicone scrapers, good sealing and scraping effects will not be achieved. Therefore, the number of scraper plates 450 is preferably 3-5.

[0032] In some embodiments, in order to prevent powder leakage and achieve airtightness, sealing rings may be provided at multiple locations on the inner wall of the housing 420 of the rotary dispensing valve 400 to improve the sealing of the entire device and prevent material leakage.

[0033] In this embodiment, in order to ensure that the material enters from the side and reduce material accumulation and jamming, a material blocking plate 460 is also installed obliquely in the rotary material dispensing valve 400. The material blocking plate 460 divides the feed port of the rotary material dispensing valve 400 into a feed chamber 470 and a material blocking chamber 480. The material enters the valve slot 411 from the feed chamber 470, thereby improving the slot fullness rate. In order to improve the sealing effect of the material blocking chamber 480, an anti-jamming block 490 is fixedly installed in the material blocking chamber 480, such as Figure 4 As shown, the anti-stuck block 490 has a plurality of tooth-shaped protrusions 491, and both sides of the protrusions 491 are inclined surfaces, which are inclined from the top of the protrusions 491 to the bottom of both sides. The bottom of the anti-stuck block 490 is provided with an arc surface 492 corresponding to the running track of the valve tooth 412, and the position where the arc surface 492 and the root of the protrusion 491 intersect is provided with an avoidance portion 493. In this embodiment, the avoidance portion 493 is a square groove, but it is not limited thereto. By setting the material baffle plate 460, the situation of the rotary distributing valve 400 being stuck due to material accumulation can be greatly reduced, thereby improving the slot full rate; by setting an anti-stuck block 490 in the material baffle chamber 480, the two sides of the protrusion 491 are inclined surfaces, and an avoidance portion 493 is set, so that even if very little material enters the material baffle chamber 480, it can fall along the inclined surface through the avoidance portion 493 into the valve slot 411 of the rotary distributing valve 400, thereby preventing the material from entering the gap between the valve core 410 and the shell 420 from the material baffle chamber 480, thereby achieving a sealing effect, and the material is guided to fall into the valve slot 411, which can improve the slot full rate.

[0034] Therefore, the material conveying system of this embodiment adopts the first air supply valve and the second air supply valve to realize air flow backblowing to break the arch, activate the powder, prevent material accumulation, and achieve the effect of sealing and improving the slot full rate; the material discharge path is restricted by the material baffle plate and the anti-stuck block, which achieves the effect of sealing and improving the slot full rate; and an elastic scraper plate is used to achieve sealing and scrape off the powder in the gap, which achieves the effect of sealing and making the weighing weight and the weight delivered to the pneumatic conveying component as consistent as possible, and by adding a hose to avoid affecting the weighing accuracy, the overall conveying accuracy is improved.

[0035] Since the rotary dispensing valve conveys materials under positive pressure during the conveying process, materials can easily pass through the gap of the dispensing valve at high speed and fall quickly, affecting the actual speed and conveying accuracy of the rotary dispensing valve; materials can easily accumulate in the gap of the sealing ring of the discharge port, affecting the falling of materials, resulting in a decrease in the slot fill rate of the rotary dispensing valve (i.e. the proportion of powder filled in the valve slot); moreover, changes in the moisture, temperature, particle size distribution and other characteristics of the powder or granular material may lead to differences in fluidity. For example, moisture absorption and agglomeration of the material may affect the speed of the rotary dispensing valve; loose materials may become compacted due to vibration or changes in air pressure during conveying, resulting in different weights under the same volume. Therefore, the conveying weight of the conveying system is nonlinear and time-varying (such as changes in material characteristics), and traditional PID parameters are difficult to adjust adaptively, and overshoot or steady-state errors are prone to occur.

[0036] In response to these situations, it is necessary to implement closed-loop control and adjust the speed of the rotary discharge valve in real time. By adjusting the speed, deviation correction and compensation can be performed to improve the conveying accuracy.

[0037] Therefore, this embodiment also provides a material conveying control method, which runs on a control device in a material conveying system and can control a servo motor connected to a rotary material dispensing valve in real time to achieve closed-loop control of material conveying. Figure 5 As shown, the specific steps include: Step S100: Calculating a first rotation speed of the servo motor according to a given material feeding speed, a volume of a material feeding trough in the material feeding device, a number of material feeding troughs in the material feeding device, and a material density; The dispensing equipment in this embodiment is a rotary dispensing valve, and the formula for calculating the material discharge weight per rotation of the rotary dispensing valve is: G=Vρa, wherein G is the weight, V is the volume of a dispensing trough in the rotary dispensing valve, ρ is the material density, and a is the number of dispensing troughs in the rotary dispensing valve.

[0038] The calculation formula for the material feeding speed is: U=Gn=Vρan; where U is the material feeding speed, G is the material feeding weight per rotation of the servo motor, and n is the rotation speed of the servo motor.

[0039] Therefore, after inputting a given material feeding speed U on the touch screen, the speed n of the servo motor can be calculated according to the above calculation formula. The driver controls the servo motor to run at the calculated speed n with a pulse command. It should be noted that, for the sake of ease of understanding, the calculation formula of the material feeding speed in this embodiment assumes that the transmission ratio between the servo motor and the rotary material dispensing valve is 1. When used, the corresponding conversion can be performed according to the transmission ratio.

[0040] For example: given that the feeding speed U is 5kg / hour and the material density ρ is 300Kg / m 3 =0.3g / cm 3, the volume of each trough of the rotary dispensing valve is V=11.9cm3, there are 14 troughs in total, the weight of material discharged by the rotary dispensing valve for each rotation of one trough is G=Vρ=11.9x0.3=3.57g, the degree of each trough is 360 / 14=25.7 degrees, that is, the rotary dispensing valve delivers 3.57g of material for every 25.7 degrees of rotation. The structure of the rotary dispensing valve determines that the material must be fed in units of one trough, so the given feeding speed is 5Kg / hour, and the first speed of the servo motor is calculated as n=[(5000 / 3.57)x25.7] / 360=99.98 rpm=1.67 rpm.

[0041] By accurately converting the given material discharge speed into the first speed of the servo motor, rather than setting the first speed of the servo motor through experience, the initial speed of the servo motor is accurate, avoiding material spillage when the speed of the rotary dosing valve is too high, and insufficient filling rate when the speed is too low, resulting in fluctuations in the conveying volume, which is beneficial to improving the conveying accuracy.

[0042] During the material conveying process, closed-loop control is achieved by executing the following steps: Step S200: measuring the first weight of the metering silo in real time, and calculating the actual unloading weight and the actual unloading speed according to the first weight and the second weight at a preset historical moment; The weighing system measures the weight of the metering silo over time in real time, and calculates the actual unloading weight and actual unloading speed. Specifically, the actual unloading weight is: g1-g0, and the actual unloading speed is: u=(g1-g0) / (t1-t0), where u is the actual unloading speed, g1 is the first weight of the metering silo at the current moment (i.e., the moment of this measurement), g0 is the second weight of the metering silo at the preset historical moment (i.e., the moment of the previous measurement), t1 is the time of this measurement moment, and t0 is the time of the previous measurement moment. It should be noted that there is no restriction on the specific time of the preset historical moment, and it can be dynamic, inferred from the measurement time interval, such as the current moment is 14:00, the measurement time interval is 5 minutes, and the preset historical moment is 13:55; it can also be static, such as the start time of a powder conveying task.

[0043] Step S300: Calculate theoretical material discharge weight based on a given material discharge speed and a time difference between the current moment and a preset historical moment; The theoretical material weight is calculated by multiplying the given material delivery speed by the time difference between the current moment and the preset historical moment.

[0044] Step S400: when the difference between the actual material feeding weight and the theoretical material feeding weight exceeds a preset range, a second rotation speed of the servo motor is determined according to the actual material feeding speed, the given material feeding speed and the actual rotation speed of the servo motor.

[0045] Calculate the difference between the actual material weight and the theoretical material weight. This difference may be caused by the deviation between the actual speed and the expected speed, or by a large difference in the density of the material. When the difference exceeds the preset range (such as ±30 grams), correction begins. The correction method is that if the actual material weight is less than the theoretical material weight, the servo motor accelerates, for example: the servo motor speeds up by 5%; if the actual material weight is greater than the theoretical material weight, the servo motor decelerates, for example: the servo motor decelerates by 5%.

[0046] This embodiment adjusts the rotation speed (i.e., the second rotation speed) of the servo motor according to the ratio of the given feeding speed to the actual feeding speed when a deviation occurs. For example, when the weight deviation is monitored to be greater than ±30g at time point t1, the ratio of the given feeding speed (e.g., 5kg / h) to the actual feeding speed (Xkg / h) is calculated, and the ratio is multiplied by the actual rotation speed n of the servo motor to obtain the second rotation speed of the servo motor, that is, the speed of the servo motor is adjusted to 5000n / X.

[0047] Since excessively high rotation speed of the rotary dispensing valve may cause material to be scattered, the present embodiment also calculates the maximum rotation speed of the rotary dispensing valve based on the equipment parameters of the rotary dispensing valve during the material conveying process. When the speed of the servo motor exceeds the maximum rotation speed, an early warning signal is sent and displayed on the touch screen. Specifically, two adjacent valve teeth on the valve core of the rotary dispensing valve form a valve slot, i.e., a dispensing slot. The present embodiment calculates the discharge time of the valve slot based on the tooth height of the valve teeth; and then calculates the maximum rotation speed of the servo motor based on the discharge time and the circumferential angle of the valve slot. For example: Assume that the tooth height of the rotary dispensing valve is ,according to , then the unloading time is ,in, is the acceleration due to gravity. Angle between the valve slot and the circumference Calculate the time per revolution: , calculate the maximum speed of the servo motor based on the time per revolution. For example: the tooth height is 15mm and the angle is 45 degrees, then , time per revolution: , maximum speed: That is, if the speed of the rotary dispensing valve exceeds 136rpm, the feeding accuracy will be affected and an alarm signal will be issued.

[0048] In some embodiments, a theoretical unloading curve and an actual unloading curve are plotted with time as the horizontal axis and unloading weight as the vertical axis. The actual unloading curve is plotted based on the actual unloading weight measured at different times in step S200, and the theoretical unloading curve is plotted based on the first speed of the servo motor calculated in step S100 and the unloading weight per rotation of the rotary dispensing valve. For example: given a unloading speed of 5 kg / hour, the unloading weight of the rotary dispensing valve per rotation of the dispensing trough is 3.57 g, and the unloading weight per rotation is 3.57×14=49.98 g. ， The first speed of the servo motor is calculated to be 1.67 rpm, and the linear relationship between the theoretical mass delivered by the rotary dosing valve to the pneumatic conveying component and time can be obtained, that is, the discharge weight per minute is: 1.67×49.98g=83.47g, and the theoretical discharge curve is drawn.

[0049] The theoretical material feeding curve can also be compared with the actual material feeding curve, and the deviation between the actual material feeding curve and the theoretical material feeding curve can be monitored in real time. If it exceeds ±30 grams, correction will be performed.

[0050] In this embodiment, when the rotary dispensing valve rotates, air is blown to the discharge port of the metering silo through the first air supply valve, so that the material accumulated in the gap between the valve core and the shell is blown back to the discharge port of the metering silo to prevent the powder from falling into the gap, thereby achieving a sealing effect and breaking the arch of the material at the discharge port of the metering silo; air is also blown to the discharge port of the metering silo through the second air supply valve to break the arch of the material at the discharge port of the metering silo. Preferably, the blowing direction of the second air supply valve and the blowing direction of the first air supply valve are staggered to achieve better sealing and arch breaking effects.

[0051] In this embodiment, a scraper plate is also arranged on the valve teeth of the valve core. A plurality of scrapers are arranged at intervals on different valve teeth. When the material dividing device rotates, the scraper plates on the valve teeth are used to scrape off the material accumulated in the gap between the valve core and the housing.

[0052] After the material is unloaded, the rotation speed of the rotary dispensing valve is increased in this embodiment, and the residual material in the mixing tank, the rotary dispensing valve and the conveying pipeline is further delivered by means of pressure relief, thereby ensuring the accuracy of the conveying weight.

[0053] In summary, the material conveying control method of this embodiment can improve the conveying accuracy by intelligently controlling the rotation speed of the servo motor to compensate for the filling rate of the rotary dispensing valve, and realize the quantitative conveying of materials and the accurate control of the conveying speed and the error of the online deviation correction conveying weight through closed-loop control. Due to the realization of closed-loop control and online deviation correction, material conveying is more flexible, and the conveying time and weight can be arbitrarily adjusted on the touch screen of the material conveying system.

[0054] The purpose of the above embodiments is to exemplarily reproduce and deduce the technical solution of the present invention, and to fully describe the technical solution, purpose and effect of the present invention. Its purpose is to make the public understand the disclosed content of the present invention more thoroughly and comprehensively, and it does not limit the scope of protection of the present invention.

[0055] The above embodiments are not exhaustive enumerations of the present invention, and there may be multiple other implementations not listed. Any replacement and improvement made without violating the concept of the present invention shall fall within the protection scope of the present invention.

Claims

1. A material conveying control method, characterized in that: include: Calculate a first rotation speed of a servo motor according to a given material unloading speed, a volume of a material distribution trough in the material distribution device, a number of material distribution troughs in the material distribution device, and a material density, wherein the servo motor is used to drive the material distribution device to rotate, and the material distribution device is provided with a plurality of material distribution troughs along a circumferential direction; During the material conveying process, the first weight of the metering silo is measured in real time, and the actual unloading weight and the actual unloading speed are calculated according to the first weight and the second weight at a preset historical moment; Calculate theoretical material unloading weight based on a given unloading speed and the time difference between the current moment and a preset historical moment; When the difference between the actual material discharge weight and the theoretical material discharge weight exceeds a preset range, the second speed of the servo motor is determined according to the actual material discharge speed, the given material discharge speed and the actual speed of the servo motor until the material delivery is completed.

2. The material conveying control method according to claim 1, characterized in that: The material distribution equipment is a rotary material distribution valve, the valve core of the rotary material distribution valve is provided with valve teeth, and two adjacent valve teeth surround the material distribution trough. During the material conveying process, the following is also included: Calculate the material discharge time of the material distribution trough according to the tooth height of the valve teeth; Calculate the maximum speed of the servo motor according to the material unloading time and the angle of the material distribution trough in the circumferential direction; When the first rotational speed or the second rotational speed exceeds the maximum rotational speed, a warning signal is sent.

3. The material conveying control method according to claim 1, characterized in that: Determining a second rotation speed of the servo motor according to the actual material feeding speed, the given material feeding speed and the actual rotation speed of the servo motor includes: Calculating the ratio of the given material feeding speed to the actual material feeding speed; The product of the ratio and the actual rotation speed is calculated to obtain the second rotation speed.

4. The material conveying control method according to claim 1, characterized in that: The material dispensing equipment is a rotary dispensing valve, which has a valve core and a shell, and there is a gap between the valve core and the inner wall of the shell. When the rotary dispensing valve rotates, air is blown to the discharge port of the metering silo through the first air supply valve, so that the material accumulated in the gap is blown back to the discharge port, and the material at the discharge port is broken, and / or, air is blown to the discharge port of the metering silo through the second air supply valve to break the arch of the material at the discharge port, and the blowing direction of the second air supply valve and the blowing direction of the first air supply valve are staggered.

5. The material conveying control method according to claim 4, characterized in that: The valve core is provided with valve teeth, and when the rotary material distributing valve rotates, the materials accumulated in the gap are scraped off by the scraper plates on the valve teeth.

6. Material conveying system, characterized in that, include: A metering silo, a weighing device, a material distribution equipment, a pneumatic conveying component, a control device, a servo motor, and a receiving silo, wherein the metering silo is used for temporarily storing materials, the weighing device is used to weigh the materials in the metering silo, the inlet of the material distribution equipment is connected to the metering silo, the outlet of the material distribution equipment is connected to the pneumatic conveying component, the outlet of the pneumatic conveying component is connected to the receiving silo, the servo motor is electrically connected to the material distribution equipment, the control device is electrically connected to the servo motor, and the control device runs the material conveying control method as described in any one of claims 1 to 5.

7. The material conveying system according to claim 6, characterized in that: It also includes a frame and a conveying pipeline, the discharge port of the pneumatic conveying component is connected to a hose, the hose is fixed on the frame, the first end of the conveying pipeline is connected to the hose, and the second end of the conveying pipeline is connected to the receiving silo.

8. The material conveying system according to claim 6, characterized in that: The material distribution equipment is a rotary material distribution valve, on which a first air supply valve and a second air supply valve are provided. The first air supply valve and the second air supply valve are arranged adjacent to the material inlet of the rotary material distribution valve, and the blowing direction of the first air supply valve and the blowing direction of the second air supply valve are arranged alternately.

9. The material conveying system according to claim 8, characterized in that: The rotary dispensing valve has a valve core, on which a plurality of valve teeth are distributed circumferentially, and a plurality of scraper plates are also provided. The scraper plates are installed on the top ends of the valve teeth and the plurality of scraper plates are distributed on the plurality of valve teeth at intervals, and the scraper plates are made of flexible material.

10. The material conveying system according to claim 8, characterized in that: A material baffle plate is obliquely installed in the rotary material distributing valve, and the feed port of the rotary material distributing valve is divided into a feed chamber and a material baffle chamber by the material baffle plate. An anti-stuck block is fixed in the material baffle chamber, and the anti-stuck block has a plurality of tooth-shaped protrusions, and both sides of the protrusion are inclined surfaces, and the inclined surfaces are arranged obliquely downward from the top of the protrusion to both sides of the protrusion, and the bottom of the anti-stuck block is provided with an arc surface, and an avoidance portion is provided at the position where the arc surface intersects with the root of the protrusion.

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