Accurate powder adding device and control method thereof

Abstract

The invention provides an accurate powder adding device which comprises a storage bin, a feeding mechanism, a weighing module, a data storage module and a central processing unit. The storage bin is used for storing powder to be added; the feeding mechanism comprises a feeding rod and a motor; the weighing module is used for collecting a powder weight signal output by the feeding mechanism; the data storage module stores a database for recording a'input acceleration-motor frequency 'mapping relation; the central processing unit is electrically connected with the data storage module, the weighing module and a motor in the feeding mechanism. The invention provides a control method of a precise powder feeding device. The control method comprises the following steps: S1, calculating a feeding acceleration; s2, matching a corresponding initial operation frequency for the motor; s3, globally updating the whole database in the data storage module; and S4, re-matching the optimal operation frequency for the motor, and enabling the motor to operate at the optimal frequency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a powder precise dosing device and a control method thereof. BACKGROUND

[0002] In the industrial fields of water treatment, chemical industry, food processing, etc., it is often necessary to accurately dose powdery materials into the system. For example, in the water treatment process, it is necessary to dose PAC (polyaluminum chloride), PAM (polyacrylamide) and other powder reagents into the reagent tank in a certain amount to achieve coagulation, flocculation and other treatment effects.

[0003] At present, the powder dosing device commonly used in the industry relies on continuous feeding mechanisms such as screw feeders or volumetric feeders. Such mechanisms are usually designed with a fixed volume, and through motor driving, a fixed volume of powder is theoretically dosed every time a fixed stroke or rotation period is completed.

[0004] However, this dosing method based on the principle of fixed volume has many inherent defects in actual application, which makes it difficult to ensure the dosing accuracy, which is specifically manifested in the following aspects: 1. The instability of the properties of the powder directly leads to the fluctuation of the dosing: the powder itself has the characteristics of uneven particle size, density variation, and easy moisture absorption and agglomeration. When the powder agglomerates or has poor flowability, it may not be able to fully fill the pre-determined volume cavity of the feeding mechanism, causing "cavity" or "bridge" phenomenon. On the contrary, when the powder is too fluffy, it may exceed the pre-determined volume. The difference in filling degree caused by the change of the material state makes there be a significant and uncontrollable random error between the actual dosing amount of a single stroke and the theoretical volume value.

[0005] 2. Systematic deviation introduced by mechanical manufacturing error: any mechanical processing has tolerances, so there is a difference between the actual volume of the feeding mechanism and the design theoretical value. This error introduced by the manufacturing link is a persistent systematic deviation that affects the dosing accuracy from the beginning of the use of the equipment and cannot be identified and corrected by the equipment itself. SUMMARY

[0006] In order to solve the technical problems existing in the background art, the present application proposes a powder precise dosing device and a control method thereof.

[0007] The powder precise dosing device proposed by the present application comprises a storage bin, a feeding mechanism, a weighing module, a data storage module and a central processing unit, wherein: The storage bin is used to store the powder to be dosed; The feeding mechanism comprises a feeding rod and a motor, wherein the feeding rod is at least partially arranged inside the storage bin, and the motor is in transmission connection with the feeding rod to drive the feeding rod to move for powder conveying; The weighing module is configured to collect the weight signal of the powder output by the feeding mechanism. The data storage module stores a database recording the mapping relationship between the feeding speed and the motor frequency. The central processing unit is electrically connected with the data storage module, the weighing module and the motor in the feeding mechanism.

[0008] Preferably, the central processing unit is configured to obtain the weight signal collected by the weighing module, calculate the actual feeding amount of the powder according to the weight signal, and obtain a correction coefficient by comparing the actual feeding amount with the theoretical feeding amount; and dynamically correct and globally update the database pre-stored in the data storage module based on the correction coefficient; and automatically match and switch the motor to the optimal operating frequency according to the updated database.

[0009] Preferably, the data storage module further stores program instructions; and the central processing unit is configured to execute the program instructions to perform the following operations. Calculate the feeding speed: calculate the feeding speed according to the input target feeding amount and feeding duration; Match the initial parameters: according to the calculated feeding speed, query the database stored in the data storage module, and match the corresponding initial operating frequency for the motor, and drive the motor to start operating at the frequency; Dynamic correction: calculate the actual feeding amount of the powder in a preset time period according to the weight signal measured and collected by the weighing module, and calculate the ratio of the actual feeding amount to the theoretical feeding amount in the time period as a correction coefficient; according to the preset formula v 新 = v × n, globally update the entire database in the data storage module, wherein v is the original value of each feeding speed in the database, v 新 is the updated value of the feeding speed, and n is the correction coefficient; Closed-loop control: query the database after dynamic correction, and re-match an optimal operating frequency for the motor in the feeding mechanism, and drive the motor to operate at the new frequency.

[0010] Preferably, the trigger condition of the dynamic correction includes at least one of the following: Periodic trigger: automatically executed every N time periods, N≥1; Event-driven trigger: automatically executed when the deviation between the actual feeding amount of the powder in a time period and the theoretical feeding amount of the powder in the time period exceeds a preset threshold.

[0011] Preferably, when the correction coefficient n>1, the central processing unit matches a lower frequency for the motor of the same feeding speed than the matched value before the update; and when the correction coefficient n<1, the central processing unit matches a higher frequency for the motor of the same feeding speed than the matched value before the update.

[0012] Preferably, the central processing unit calculates the actual dosage according to the actual dosage calculation formula stored in the data storage module: Q 实 =Q 起 - Q 终 , wherein: Q 起 is the initial weight recorded by the weighing module at the beginning of the preset time period, and Q 终 is the final weight recorded by the weighing module after the end of the preset time period.

[0013] Preferably, the central processing unit calculates the theoretical dosage according to the theoretical dosage calculation formula stored in the data storage module: Q 理 =f× v × t, wherein: f is the running frequency of the motor within the preset time period, v is the dosage speed corresponding to f, and t is the length of the preset time period.

[0014] Preferably, the outer wall of the storage bin is provided with a vibrator.

[0015] Preferably, the part of the feeding rod located inside the storage bin is provided with a cavity for carrying the powder, the part of the storage bin corresponding to the cavity is provided with a discharge port, and the motor is used to drive the feeding rod to rotate.

[0016] The control method of the powder precise dosing device provided by the application comprises the following steps: S1, input the target dosage and the dosage duration, and the central processing unit calculates the dosage speed according to the input target dosage and the dosage duration; S2, the central processing unit queries the database stored in the data storage module according to the calculated dosage speed, so as to match the initial running frequency corresponding to the motor and drive the motor to run at the frequency; S3, when entering the dynamic correction stage, the central processing unit calculates the ratio of the actual dosage to the theoretical dosage of the powder within the preset time period according to the weight signal measured and collected by the weighing module, so as to take the ratio as a correction coefficient, and updates the entire database in the data storage module according to the preset formula v 新 = v × n; S4, after the dynamic correction stage ends, the central processing unit queries the database again, matches the optimal running frequency of the motor again, and drives the motor to run at the optimal frequency.

[0017] Preferably, the calculation of the dosage speed comprises the following steps: Step one: plan the feeding time sequence Divide the dosage duration into multiple continuous dosage periods, and set the period duration for each dosage period; Step two: calculate the dosage speed According to the input target adding amount, a cycle target adding amount is allocated to each adding cycle, and according to the allocated cycle target adding amount and cycle duration, an adding speed of each adding cycle is calculated.

[0018] Preferably, the dynamic correction specifically comprises the following steps: Step one: calculating the actual adding amount A specific cycle is selected from the adding cycle sequence as a calibration cycle, and the actual adding amount of the powder in the calibration cycle is calculated by the weight loss method; Step two: calculating the correction coefficient The theoretical adding amount in the calibration cycle is obtained, and the correction coefficient n is calculated according to the formula n = Q 实 / Q 理 Step three: performing correction According to the formula v 新 = v × n, the database in the data storage module is globally updated.

[0019] The powder precision adding device and control method provided by the application realize automatic correction and continuous optimization of system operation parameters through the database of pre-set 'adding speed-motor frequency' mapping relationship, combined with the monitoring of the actual adding amount by the weighing module and the closed-loop control of the central processing unit. The scheme can effectively compensate for the adding deviation caused by the change of the physical properties of the powder, the wear of the mechanical parts and the fluctuation of the environmental factors, improve the long-term adding precision and operation consistency of the system, reduce the dependence on external intervention and manual adjustment, and enhance the self-adaptive ability and reliability of the device under continuous production conditions. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The structure diagram of the powder precision adding device provided by the application. DETAILED DESCRIPTION

[0021] Embodiment one: powder precision adding device Referring to Figure 1 , the powder precision adding device provided by the application comprises a storage bin 1, a feeding mechanism, a weighing module 2, a data storage module and a central processing unit, wherein: The storage bin 1 is used for storing the powder to be added. In order to improve the flowability of the powder and prevent bridging or arching, a vibrator 5 can be preferably installed on the outer wall of the storage bin 1.

[0022] ​The feeding mechanism comprises a feeding rod 3 and a motor 4, wherein the feeding rod 3 is at least partially arranged in the inside of the storage bin 1, and a cavity for carrying the powder is arranged at the part of the feeding rod 3 in the storage bin 1. The lower part of the storage bin 1 corresponding to the cavity constitutes a feeding opening. The motor 4 is in driving connection with the feeding rod 3, and is used to drive the feeding rod 3 to rotate, so as to deliver the powder in the cavity to the feeding opening.

[0023] The weighing module 2 is preferably a weighing sensor, and the weighing module 2 is arranged below the feeding mechanism, and is used to collect the weight signal of the powder output by the feeding mechanism.

[0024] The data storage module can be various memories, and the data storage module stores program instructions and a database recording the mapping relationship between the feeding speed and the running frequency of the motor 4. The database records the corresponding relationship between different feeding speeds and the running frequency of the motor 4.

[0025] The central processing unit can be a processor, a controller or a PLC, etc. The central processing unit is electrically connected with the data storage module, the weighing module 2 and the motor 4 in the feeding mechanism, so as to obtain the weight signal collected by the weighing module 2, calculate the actual feeding amount of the powder according to the weight signal, and obtain the correction coefficient by comparing the actual feeding amount with the theoretical feeding amount; and dynamically correct and globally update the database pre-stored in the data storage module based on the correction coefficient; and automatically match and switch the motor 4 to the optimal running frequency according to the updated database.

[0026] Through the above closed-loop control, the feeding deviation caused by the change of the characteristics of the powder, mechanical wear and other factors can be compensated in real time, so that the powder feeding can be realized continuously and with high precision.

[0027] The specific implementation scheme is that the central processing unit is configured to execute the program instructions stored in the data storage module, so as to realize the following operations: Calculate the feeding speed: according to the input target feeding amount and feeding duration, the feeding speed is calculated; Match the initial parameters: according to the calculated feeding speed, the database stored in the data storage module is queried, so as to match the corresponding initial running frequency for the motor 4, and drive the motor 4 to start running at the frequency; Dynamically correct: according to the weight signal measured and collected by the weighing module 2, the actual feeding amount of the powder in a preset time period is calculated, and the ratio of the actual feeding amount to the theoretical feeding amount in the time period is calculated as a correction coefficient; according to a preset formula v 新 = v × n, the entire database in the data storage module is globally updated, wherein v is each feeding speed value in the database, and v 新 is the updated feeding speed value; Closed-loop control: query the dynamically corrected database, and re-match an optimal operating frequency for the motor 4 in the feeding mechanism, and drive the motor 4 to operate at the new frequency.

[0028] In further embodiments, the trigger condition of dynamic correction includes at least one of the following: Periodic trigger: automatically executed after every interval of N time periods, N≥1; Event-driven trigger: automatically executed when the deviation between the actual feeding amount of the powder and the theoretical feeding amount of the powder in a certain time period exceeds the preset threshold.

[0029] In further embodiments, the logic of the central processing unit for re-matching the operating frequency of the motor 4 is as follows: When the correction coefficient n>1, it indicates that the actual feeding amount of the powder is more than the theoretical value, at this time, the system will match the frequency of the motor 4 with the same feeding speed to be lower than the matching value before updating, so as to slow down the feeding.

[0030] When the correction coefficient n<1, it indicates that the actual feeding amount of the powder is less than the theoretical value, at this time, the system will match the frequency of the motor 4 with the same feeding speed to be higher than the matching value before updating, so as to speed up the feeding.

[0031] Embodiment two: control method of powder precise feeding device This embodiment details the control method of the above device, which is executed by the central processing unit, and the specific steps are as follows: The control method of the powder precise feeding device proposed by the application comprises the following steps: 1. Calculate the feeding speed stage: input the target feeding amount and the feeding duration to calculate the feeding speed, and the specific steps are as follows: Step one: plan the feeding time sequence. Divide the feeding duration into multiple consecutive feeding periods, and set the period duration for each feeding period; Step two: calculate the feeding speed. According to the input target feeding amount, assign a period target feeding amount to each feeding period; according to the formula: period feeding speed = period target feeding amount / period duration, calculate the required feeding speed v of each feeding period.

[0032] 2. Match the initial parameters stage: for each feeding period, the central processing unit queries the pre-stored database in the data storage module, and automatically matches the corresponding initial operating frequency f for the motor 4 according to the calculated feeding speed v of the corresponding period, and drives the motor 4 to start operating at this frequency; 3. Dynamic correction stage: the system selects a specific feeding period as the calibration period, and the trigger condition of the calibration period includes at least one of the following: Periodic trigger: automatically executed after every N dosing cycles, N≥1; Event-driven trigger: immediately executed when the deviation between the actual dosing amount of powder and the theoretical dosing amount of powder in a certain dosing cycle exceeds the preset threshold.

[0033] The specific steps of dynamic correction are as follows: Step one: calculate the actual dosing amount Q 实 . Select a specific cycle from the sequence of dosing cycles as the calibration cycle; in the selected calibration cycle, the central processing unit starts the weighing module 2 to measure and calculates the actual dosing amount by the loss-in-weight method. The calculation formula is: Q 实 = Q 起 - Q 终 , where Q 起 is the initial weight recorded by the weighing module 2 at the beginning of the calibration cycle, and Q 终 is the final weight at the end of the cycle.

[0034] Step two: calculate the correction coefficient n. The central processing unit obtains the theoretical dosing amount Q 理 of the calibration cycle. Q 理 can be obtained according to the formula Q 理 = f × v × t, t is the duration of the calibration cycle, or directly from the system set period target dosing amount. Then, according to the formula n = Q 实 / Q 理 , the correction coefficient n of this calibration is calculated; Step three: execute dynamic correction. The central processing unit updates the entire database in the data storage module globally according to the formula v 新 = v × n. Where v is the original dosing speed value in the database, and v 新 is the updated dosing speed value.

[0035] 4. Closed-loop control phase: in the dosing cycle after the calibration cycle, the system enters the closed-loop control mode based on the updated database: the central processing unit queries the dynamically corrected database according to the dosing speed v of the next dosing cycle, automatically matches an optimal operating frequency for the motor 4 in the feeding mechanism, and drives the motor 4 to operate at the new frequency.

[0036] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can make equivalent replacement or change according to the technical solution and inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A powder precision dosing device, characterized in that, include: The material storage silo (1), feeding mechanism, weighing module (2), data storage module and central processing unit, wherein: Storage silo (1) is used to store powder to be added; The feeding mechanism includes a feeding rod (3) and a motor (4), wherein the feeding rod (3) is at least partially inserted inside the storage bin (1), and the motor (4) is connected to the feeding rod (3) to drive the feeding rod (3) to move for powder conveying; The weighing module (2) is used to collect the powder weight signal output by the feeding mechanism; The data storage module contains a database that records the mapping relationship between "feeding speed and motor (4) frequency"; The central processing unit is electrically connected to the data storage module, the weighing module (2), and the motor (4) in the feeding mechanism.

2. The powder precise dosing device according to claim 1, characterized in that, The central processing unit is used to acquire the weight signal collected by the weighing module (2), calculate the actual amount of powder added, and obtain the correction coefficient by comparing it with the theoretical amount added; and dynamically correct and globally update the database pre-stored in the data storage module based on the obtained correction coefficient; and automatically match and switch the motor (4) to the optimal operating frequency according to the updated database.

3. The powder precise dosing device according to claim 2, characterized in that, The data storage module also stores program instructions; the central processing unit is configured to execute the program instructions to perform the following operations; Calculate the dosing rate: Calculate the dosing rate based on the input target dosing amount and dosing duration; Matching initial parameters: Based on the calculated addition speed, query the database stored in the data storage module, match the corresponding initial operating frequency for the motor (4), and drive the motor (4) to start running at that frequency; Dynamic correction: Based on the weight signal collected by the weighing module (2), the actual amount of powder added within the preset time period is calculated, and the ratio of the actual amount added to the theoretical amount added within the time period is calculated as the correction coefficient. According to the preset formula v 新 = v × n, performs a global update on the entire database in the data storage module, where v represents the original acceleration values ​​in the database, v 新 The updated injection velocity value, where n is the correction coefficient; Closed-loop control: Query the dynamically corrected database, re-match an optimal operating frequency for the motor (4) in the feeding mechanism, and drive the motor (4) to operate at this new frequency.

4. The powder precision dosing device according to claim 3, characterized in that, The triggering conditions for dynamic correction include at least one of the following: Periodic trigger: Automatically executed after every N time intervals, where N≥1; Event-driven trigger: Automatically executed when the deviation between the actual dosage of powder and the theoretical dosage of powder within a certain time period exceeds a preset threshold.

5. The powder precise dosing device according to claim 3, characterized in that, When the correction coefficient n > 1, the frequency of the motor (4) matched by the central processing unit for the same loading speed is lower than the matching value before the update; when the correction coefficient n < 1, the frequency of the motor (4) matched by the central processing unit for the same loading speed is higher than the matching value before the update.

6. The powder precise dosing device according to claim 3, characterized in that, The central processing unit calculates the dosage based on the formula stored in the data storage module: Q 实 = Q 起 - Q 终 Calculate the actual dosage, where: Q 起 Q is the initial weight recorded by the weighing module (2) at the start of the preset time period. 终 The final weight recorded by the weighing module (2) after the preset time period ends; Preferably, the central processing unit calculates the dosage based on the theoretical dosage formula stored in the data storage module: Q 理 =f ×v × t, calculate the theoretical amount of feed, where: f is the operating frequency of the motor (4) within the preset time period, v is the feed rate corresponding to f, and t is the duration of the preset time period.

7. The powder precise dosing device according to claim 1, characterized in that, The outer wall of the storage silo (1) is equipped with a vibrator (5); Preferably, the feeding rod (3) is provided with a cavity for holding powder in the part inside the storage bin (1), and the storage bin (1) is provided with a discharge port corresponding to the lower part of the cavity. The motor (4) is used to drive the feeding rod (3) to rotate.

8. A control method for a powder precision dosing device as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Input the target dosage and dosage duration. The central processing unit calculates the dosage rate based on the input target dosage and dosage duration. S2. The central processing unit queries the database stored in the data storage module according to the calculated feeding speed to match the corresponding initial operating frequency for the motor (4) and drive the motor (4) to run at this frequency. S3. When entering the dynamic correction stage, the central processing unit calculates the ratio of the actual dosage of powder to the theoretical dosage within a preset time period based on the weight signal measured and collected by the weighing module (2), using it as the correction coefficient, and then calculates the ratio based on the preset formula v. 新 = v × n, which performs a global update on the entire database in the data storage module; S4. After the dynamic correction phase is completed, the central processing unit queries the database again to rematch the optimal operating frequency for the motor (4) and the motor (4) runs at the optimal frequency.

9. The control method according to claim 8, characterized in that, The calculation of the dosing velocity includes the following steps: Step 1: Plan the material feeding sequence The duration of the injection is divided into multiple consecutive injection cycles, and a cycle duration is set for each injection cycle. Step 2: Calculate the injection rate Based on the input target dosage, a target dosage for each dosage cycle is assigned, and the dosage rate for each dosage cycle is calculated based on the assigned target dosage and the duration of the cycle.

10. The control method according to claim 9, characterized in that, Dynamic correction specifically includes the following steps: Step 1: Calculate the actual dosage A specific period is selected from the dosing cycle sequence as the calibration period; and the actual amount of powder added during the calibration period is calculated using the weight loss method. Step 2: Calculate the correction coefficient Obtain the theoretical dosage within the calibration period, and apply the formula n = Q. 实 / Q 理 Calculate the correction factor n; Step 3: Perform calibration According to formula v 新 = v × n, performs a global update on the database in the data storage module.

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