Method and system for controlling particle size and productivity of airflow crushing device

Abstract

The invention discloses a particle size and productivity control method and control system of an airflow pulverization device, and belongs to the technical field of material pulverization control of the airflow pulverization device, the given value ranges of frequency converters corresponding to a grader motor, a pulverizer motor, an induced draft fan motor and a feeder motor are set respectively, and the particle size target value rd is set; meanwhile, setting a target value rd of the particle size and a maximum particle size error value delta of an actual value of the particle size; judging whether the difference between the target value of the particle size and the actual value of the particle size is smaller than or equal to the maximum particle size error value delta or not; if not, according to the priorities of the operation process parameters, the rotating speed of the grading motor, the rotating speed of the crusher motor, the rotating speed of the induced draft fan motor and the rotating speed of the feeder motor are sequentially adjusted through a positive sequence or reverse sequence search method till the particle size meets the system production requirement. According to the invention, the particle size of the material particles can meet the production requirement, and the productivity of the crushing device can be optimal.

Description

Technical Field

[0001] The invention relates to a method and a control system for controlling the particle size and production capacity of an air flow pulverizing device, and belongs to the technical field of controlling pulverized materials by an air flow pulverizing device. Background Art

[0002] Airflow milling technology has been widely used in the fields of new energy battery materials, biopharmaceuticals, semiconductor materials, military manufacturing, food processing, metallurgical industry, petrochemical industry, solid waste recycling, etc., because its product particles have high purity, low pollution, narrow particle size distribution, good dispersibility and high particle activity. Airflow milling to prepare powders has played a key role in many national economic fields and national defense science and technology undertakings, and many emerging high-tech industrial groups have also been derived due to the continuous advancement of this technology.

[0003] The airflow pulverizing device is mainly composed of a spiral feeding system, an airflow classification system, an air compressor, an induced draft fan cyclone collector, a bag dust collector and an induced draft fan. The main structure of the airflow classification system consists of a lower airflow pulverizing area and an upper airflow classification area. The airflow pulverizing area has a horizontally placed Laval nozzle, and the airflow classification area mainly has a three-dimensionally placed classification worm gear and a motor transmission system. The principle of airflow pulverization is that after the compressed air is cooled, filtered, and dried, it forms a supersonic airflow through the Laval nozzle and is injected into the pulverizer to fluidize the material. The accelerated material undergoes violent collision, friction, and shearing to form particle crushing. The crushed fine powder is transported to the upper turbine classifier with the rising airflow. Under the action of the centrifugal force of the classifying wheel and the suction force of the induced draft fan, the fine powder that meets the fineness is discharged and enters the lower classification for further sorting or collection. The purified gas is discharged by the induced draft fan.

[0004] In the actual pulverization production process, due to the wide variety of pulverized materials, the great differences in physical and chemical structures, and the inherent gas-solid two-phase characteristics of the pulverization process, although domestic and foreign scholars have conducted orthogonal tests on certain specific materials and obtained the optimized empirical regression formula for process parameters through regression analysis, once different materials are replaced, the orthogonal test needs to be repeated. At the same time, due to the limitations of the orthogonal test samples, there is a large error between the particle size obtained by the empirical regression formula and the particle value detected during the production process. In production, it is still necessary to adjust the process operation parameters by manual trial and error to meet the particle size requirements.

[0005] The Chinese invention patent with the announcement number CN115814915B discloses a particle size control method for an airflow pulverizing device. By real-time online adjustment and control of the classifier motor speed and the induced draft fan speed, the feedforward compensation matrix method is adopted to eliminate the mutual coupling relationship between the two variables, so that the dust particle size can quickly reach the set value and the particle size of the pulverized material can be accurately controlled. The control method adopted is a decoupling algorithm, which depends on an accurate mathematical model. A large number of experiments are required to establish an accurate mathematical model. Once the pulverizing device is replaced with different materials, a large number of experiments are required to obtain the mathematical model. The disadvantage is that a large amount of raw materials is wasted, the production cost is increased, and the debugging cycle is long. In addition, the above-mentioned control method does not consider the problem of production capacity when adjusting the particle size.

[0006] In summary, a universal mathematical model of parameters for airflow pulverizing devices has not yet been established. The control of factors affecting airflow pulverizing mainly relies on the operator's own long-term accumulated experience and a large number of orthogonal tests. This inevitably results in a long on-site commissioning cycle for pulverizing equipment, a large amount of expensive raw materials is wasted, production energy consumption is increased, and the production efficiency of powder preparation is reduced, and the problem of low output cannot be solved. Summary of the invention

[0007] In view of the deficiencies in the background technology, the present invention provides a method and a control system for the particle size and production capacity of an air flow pulverizing device. This method is independent of the characteristics of the pulverized material and does not require the establishment of a mathematical model of the pulverizing device. According to the influence of the main operating parameters of the pulverizing device on the particle size and production capacity, an optimal priority search algorithm is adopted to achieve the particle size of the material meeting the production requirements while optimizing the production capacity of the pulverizing device.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for controlling the particle size and capacity of an air flow pulverizing device, step 1, according to the process design requirements of the air flow pulverizing device, respectively set the given value range of the inverter corresponding to the classifier motor, the pulverizer motor, the induced draft fan motor and the feeder motor, and set the particle size target value r d , and set the target value of particle size r d The maximum particle size error δ between the actual particle size and the actual particle size; Step 2: Start the airflow crushing device and use a dry laser particle size tester to detect the actual value of the particle size of the current output material. d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 3; Step 3: The given value of the first frequency converter controlling the classifier motor adopts the positive sequence search method, and the current given value increases by a fixed step length. The actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 4; Step 4: The given value of the second frequency converter controlling the motor of the pulverizer is searched in reverse order. The current given value is reduced by a fixed step length, and the actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 5; Step 5: The given value of the third frequency converter controlling the induced draft fan motor is searched in reverse order. The current given value is reduced by a fixed step length. The actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 6; Step 6: The given value of the fourth frequency converter controlling the feeder motor is searched in reverse order. The current given value is reduced by a fixed step length. The actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise return to step 3; Step 7, taking the current given values ​​of the first frequency converter controlling the classifier motor, the second frequency converter controlling the pulverizer motor, the second frequency converter controlling the induced draft fan motor and the fourth frequency converter controlling the feeder motor as the final set values, and terminating the execution of the search program.

[0009] Further, the given value range of the first frequency converter for initializing the control of the classifier motor is [u min ,u max ], the given value range of the second inverter controlling the grinder motor is [v min , v max ], the given value range of the third inverter controlling the induced draft fan motor is [w min , w max ], the given value range of the fourth inverter controlling the feeder motor is [z min , z max ].

[0010] Furthermore, the forward search method is to search with a fixed step size in a direction from small to large within the range of the given value of the frequency converter; the reverse search method is to search with a fixed step size in a direction from large to small within the range of the given value of the frequency converter.

[0011] Furthermore, the system sampling period T is set to 10 seconds.

[0012] A control system for particle size and production capacity of an air flow pulverizing device, comprising an embedded control system, wherein the embedded control system is connected to an industrial computer via an RS-485 serial port, and a first regulator, a second regulator, a third regulator and a fourth regulator are integrated in the embedded control system; Also includes a first frequency converter, a second frequency converter, a third frequency converter and a fourth frequency converter; The first regulator and the first frequency converter are used to control the classifier motor, the second regulator and the second frequency converter are used to control the crushing motor, the third regulator and the third frequency converter are used to control the induced draft fan motor, and the fourth regulator and the fourth frequency converter are used to control the feeder motor.

[0013] Furthermore, the particle size target value r d , the first regulator, the first frequency converter and the classifier motor form a classifier motor speed control loop; The classifier motor speed control loop is based on the particle size target value r d The positive sequence search method is used to adjust the speed of the classifier motor through the first regulator and the first frequency converter.

[0014] Furthermore, the target particle size r d The second regulator, the second frequency converter and the pulverizer motor form a pulverizer motor speed control loop, which controls the pulverizer motor speed according to the particle size target value r d The motor speed of the pulverizer is adjusted by the second regulator and the second frequency converter according to the reverse search method.

[0015] Furthermore, the particle size target value r d , the third regulator, the third frequency converter and the induced draft fan motor form an induced draft fan motor speed control loop, which controls the induced draft fan motor speed according to the particle size target value r d The reverse search method is used to adjust the speed of the induced draft fan motor through the third regulator and the third frequency converter.

[0016] Furthermore, the target particle size r d The fourth regulator, the fourth frequency converter and the feeder motor form a feeder motor speed control loop. The feeder motor speed control loop adjusts the speed of the feeder motor according to the target particle size r. d And the reverse search method, through the fourth regulator and the fourth frequency converter, to adjust the amount of material entering the crusher per unit time.

[0017] After adopting the above technical solution, the present invention has the following advantages compared with the prior art: The judgment is made based on whether the difference between the target value of the particle size and the actual value of the particle size is less than or equal to the maximum particle size error value δ; if not, the classification motor speed, crusher motor speed, induced draft fan motor speed and feeder motor speed are adjusted in sequence according to the priority of the operating process parameters using a positive or reverse search method until the particle size meets the system production requirements, which greatly shortens the on-site debugging time, enables the material to quickly reach the qualified particle size, reduces material waste, and at the same time can meet the optimal production capacity.

[0018] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the processing process of the pulverizing device in the present invention; Figure 2 It is a general scheme block diagram of the particle size and capacity control system of the air flow pulverizing device in the present invention; Figure 3 It is a control principle diagram of the particle size and capacity control system of the air flow pulverizing device in the present invention; Figure 4 It is a flow chart of the steps of the particle size and capacity control method of the air flow pulverizing device in the present invention.

[0020] In the figure, 1- air compressor, 2- air storage tank, 3- cold dryer, 4- air inlet valve, 5- feeder, 6- pulverizer, 7- classifier, 8- dry laser particle size tester, 9- cyclone collector, 10- dust collector, 11- induced draft fan, 12- electric control cabinet of pulverizing device control system. DETAILED DESCRIPTION

[0021] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0022] like Figure 1 As shown, an air flow pulverizing device comprises an air compressor 1, an air storage tank 2, a cold dryer 3, a pulverizer 6, a pulverizer 6, a classifier 7 installed on the upper part of the pulverizer 6, a cyclone collector 9, a dust collector 10, an induced draft fan 11 and an electric control cabinet 12 for controlling the pulverizing device control system for controlling the entire device, an air intake valve 4 is provided on the pipe section connecting the cold dryer 3 and the pulverizer 6, a dry laser particle size tester 8 is provided on the pipe section connecting the classifier 7 and the cyclone collector 9, and the pulverizing device also comprises a feeder 5, which is used to feed the pulverizer 6.

[0023] The compressed air generated by the air compressor 1 enters the air storage tank 2, and then is cooled, filtered and dried by the cold dryer 3. It is then injected into the pulverizer 6 through the inlet valve 4 and the Laval nozzle to form a supersonic airflow. The pulverized material enters the pulverizer 6 through the feeder 5. Under the action of the high-speed airflow, the material particles are subjected to violent impact, collision, friction and shearing to achieve pulverization. The pulverized fine powder is transported to the upper classifier 7 with the rising airflow. Under the action of the centrifugal force of the classifier wheel and the suction force of the induced draft fan 11, the fine powder that meets the fineness requirements is discharged and enters the cyclone collector 9 for collection. The dust-containing gas is filtered and purified by the dust collector 10 and then discharged into the atmosphere by the induced draft fan 11.

[0024] like Figure 2 and Figure 3 The present invention provides a control system for the particle size and production capacity of an air flow pulverizing device for controlling the air flow pulverizing device, wherein the control system includes an embedded control system, which is connected to an industrial computer via an RS-485 serial port, and the embedded control system includes a first regulator, a second regulator, a third regulator and a fourth regulator integrated in a single-chip microcomputer, and the control system also includes a first frequency converter, a second frequency converter, a third frequency converter and a fourth frequency converter; the first regulator and the first frequency converter are used to control a classifier motor, the second regulator and the second frequency converter are used to control a pulverizing motor, the third regulator and the third frequency converter are used to control an induced draft fan motor, and the fourth regulator and the fourth frequency converter are used to control a feeder motor.

[0025] The primary task of the air flow milling device is to meet the particle size requirements of the processed material, followed by the optimal production capacity of the milling device. Therefore, it is necessary to analyze the main factors that affect the particle size, and then analyze the impact of the main factors affecting the particle size on the production capacity. Through references and prior knowledge, it can be known that the main factors affecting the particle size are: classifier motor speed, mill motor speed, induced draft fan motor speed and feeder motor speed. The impact of these four factors on particle size and production capacity is as follows: (1) Effect of classifier motor speed on particle size and production capacity Impact on particle size: As the classifier motor speed increases, the particle size of the product particles output by the airflow pulverizing device becomes smaller; as the classifier motor speed decreases, the particle size of the product particles output by the airflow pulverizing device increases. Impact on production capacity: As the classifier motor speed increases, the output capacity of the airflow crushing device decreases; as the classifier motor speed decreases, the output capacity of the airflow crushing device increases.

[0026] (2) The influence of the motor speed of the pulverizer on particle size and production capacity Impact on particle size: As the motor speed of the pulverizer increases, the particle size of the product output by the airflow pulverizing device becomes smaller; as the motor speed of the pulverizer decreases, the particle size of the product output by the airflow pulverizing device becomes larger.

[0027] Impact on production capacity: As the motor speed of the pulverizer increases, the output capacity of the airflow pulverizing device increases; as the motor speed of the pulverizer decreases, the output capacity of the airflow pulverizing device decreases.

[0028] (3) Effect of induced draft fan motor speed on particle size and production capacity Impact on particle size: As the induced draft fan motor speed increases, the particle size of the product output by the airflow pulverizing device becomes larger; as the induced draft fan motor speed decreases, the particle size of the product output by the airflow pulverizing device becomes smaller.

[0029] Impact on production capacity: As the induced draft fan motor speed increases, the output capacity of the airflow crushing device increases; as the induced draft fan motor speed decreases, the output capacity of the airflow crushing device decreases.

[0030] (4) Effect of feeder motor speed on particle size and production capacity Impact on particle size: As the feeder motor speed increases, the particle size of the product output by the airflow pulverizing device becomes larger; as the feeder motor speed decreases, the particle size of the product output by the airflow pulverizing device becomes smaller.

[0031] Impact on production capacity: As the feeder motor speed increases, the output capacity of the airflow crushing device increases; as the feeder motor speed decreases, the output capacity of the airflow crushing device decreases.

[0032] According to the influence of classifier motor speed, crusher motor speed, induced draft fan motor speed and feeder motor speed on particle size and production capacity, in order to achieve optimal particle size control and production capacity, it is proposed to use the forward search method and the reverse search method respectively when finding the optimal operating parameters.

[0033] Particle size target value r d The first regulator, the first frequency converter and the classifier motor form a classifier motor speed control loop, which controls the classifier motor speed according to the particle size target value r d and the positive sequence search method, through the first regulator and the first frequency converter, accurately adjust the classifier motor speed to achieve the classification and screening of material particles; Particle size target value r d The second regulator, the second frequency converter and the pulverizer motor form a pulverizer motor speed control loop, which controls the pulverizer motor speed according to the particle size target value r d and reverse search method, through the second regulator and the second frequency converter, the motor speed of the pulverizer is precisely adjusted, thereby changing the motor speed of the pulverizer; Particle size target value r d , the third regulator, the third frequency converter and the induced draft fan motor form an induced draft fan motor speed control loop, which controls the induced draft fan motor speed according to the particle size target value r d and reverse search method, through the third regulator and the third frequency converter, to adjust the speed of the induced draft fan motor; Particle size target value r d The fourth regulator, the fourth frequency converter and the feeder motor form a feeder motor speed control loop. The feeder motor speed control loop adjusts the speed of the feeder motor according to the target particle size r. d And the reverse search method, through the fourth regulator and the fourth frequency converter, to adjust the amount of material entering the crusher per unit time.

[0034] The present invention provides a method for controlling the particle size and capacity of an air flow pulverizing device. Figure 4 , including the following steps: Step 1: According to the process design requirements of the airflow pulverizing device, set the given value range of the inverter corresponding to the classifier motor, pulverizer motor, induced draft fan motor and feeder motor, and set the particle size target value r d , and set the target value of particle size r d and the maximum particle size error δ of the actual particle size.

[0035] The given value range of the first inverter for initializing the control of the classifier motor is [u min ,u max ], the given value range of the second inverter controlling the grinder motor is [v min , v max ], the given value range of the third inverter controlling the induced draft fan motor is [w min , w max ], the given value range of the fourth inverter controlling the feeder motor is [z min , z max ], and set the system sampling period T = 10 seconds; Step 2: Start the airflow crushing device and use a dry laser particle size tester to detect the actual value of the particle size of the current output material. d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 3; Step 3: The given value of the first frequency converter controlling the classifier motor adopts the positive sequence search method, and the current given value increases by a fixed step length. The actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 4; Step 4: The given value of the second frequency converter controlling the motor of the pulverizer is searched in reverse order. The current given value is reduced by a fixed step length, and the actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 5; Step 5: The given value of the third frequency converter controlling the induced draft fan motor is searched in reverse order. The current given value is reduced by a fixed step length. The actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 6; Step 6: The given value of the fourth frequency converter controlling the feeder motor is searched in reverse order. The current given value is reduced by a fixed step length. The actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise return to step 3; Step 7, taking the current given values ​​of the first frequency converter controlling the classifier motor, the second frequency converter controlling the pulverizer motor, the second frequency converter controlling the induced draft fan motor and the fourth frequency converter controlling the feeder motor as the final set values, and terminating the execution of the search program.

[0036] The given value range of the first inverter controlling the graded motor is [u min ,u max ], the first frequency converter adopts the positive sequence search method, the so-called positive sequence search method is to start from U min to U max The search is performed in a fixed step size in the direction (from small to large).

[0037] The initial given value u of the first frequency converter min With a fixed step size of △u to u maX Step in the direction and record the target particle size r d The actual value of the current particle size y d (k), and record the given value u(k+1) of the first frequency converter corresponding to △e1(k+1); in,

[0038] According to the influence of the speed of the classifying motor on the particle size and production capacity, the positive sequence search method is adopted. As the given value of the first frequency converter gradually increases, the speed of the classifier gradually increases, which can make the output product particles of the air flow crushing device smaller. Then, the speed of the crusher motor, the speed of the induced draft fan motor and the speed of the feeder motor are adjusted in sequence to meet the material processing particle size requirements. If the reverse search method is used, at the beginning, due to the high speed of the classifying motor, under the action of high-speed centrifugal force, the powder that meets the particle size will return to the crusher for secondary crushing, thus reducing the production capacity.

[0039] The given value range of the second inverter controlling the grinder motor is [v min , v max ], the second frequency converter adopts the reverse search method, the so-called reverse search method is to start from v max to v min The search direction is stepped with a fixed step size.

[0040] The initial set value v of the second inverter max With a fixed step size of △v to v min Step in the direction and record the target particle size r d The actual value of the current particle size y d (k), and record the second inverter given value v(k+1) corresponding to △e2(k+1); in,

[0041] According to the influence of the motor speed of the pulverizer on the particle size and production capacity, the reverse search method is adopted. The motor speed of the pulverizer changes from large to small, and the output product particles of the airflow pulverizing device become smaller. Although the production capacity will also decrease, once the particle size requirements of the system are met at this time, the motor speed of the pulverizer will no longer decrease, and the production capacity will no longer decrease. If the forward search method is used, the particle size will gradually decrease due to the step-by-step increase in the motor speed of the pulverizer, which will prolong the time of the particle size adjustment process and the production capacity is not optimal.

[0042] The given value range of the third inverter controlling the induced draft fan motor is [w min , w max ], the third frequency converter adopts the reverse search method, the so-called reverse search method is to start from w max tow min The search direction is stepped with a fixed step size.

[0043] The initial given value w of the third inverter max With a fixed step size of △w to w min Step in the direction and record the target particle size r d and the current actual particle size value y d(k), and record the inverter setting value w(k+1) corresponding to △e3(k+1) for controlling the induced draft fan motor; in,

[0044] According to the influence of the induced draft fan motor speed on the particle size and production capacity, the reverse search method is adopted. The induced draft fan motor speed is gradually reduced, which can gradually reduce the particle size. Although the production capacity will also decrease, once the particle size requirements of the system are met at this time, the reverse search algorithm stops stepping, the induced draft fan motor speed no longer decreases, and the production capacity no longer decreases.

[0045] The given value range of the fourth inverter controlling the feeder motor is [z min , z max ], the fourth frequency converter adopts the reverse search method, the so-called reverse search method is to start from z max To z min The search direction is stepped with a fixed step size.

[0046] The initial set value of the third inverter is z max With a fixed step size of △z to z min Step in the direction and record the target particle size r d and the current actual particle size value y d (k), and record the given value z(k+1) of the frequency converter of the feed motor corresponding to △e4(k+1); in,

[0047] According to the effect of feeder motor speed on particle size and production capacity, the reverse search algorithm is used. The speed of the induced draft fan motor is gradually reduced, which can gradually reduce the particle size. Although the production capacity will also decrease, once the particle size requirements of the system are met at this time, the reverse search algorithm stops stepping, the speed of the induced draft fan motor no longer decreases, and the production capacity no longer decreases. If the forward search algorithm is used, the speed of the induced draft fan motor increases step by step, although the production capacity increases, the particle size will gradually increase.

[0048] The specific working principle of the present invention: The main factors affecting the particle size of the air flow pulverizing device are: the speed of the classifying motor, the speed of the pulverizer, the speed of the induced draft fan and the speed of the feeder. Therefore, the air flow pulverizing device belongs to a multivariable priority control system. When the operating process parameters of the pulverized material are adjusted by the embedded control system, first, it is judged whether the difference between the target value of the particle size and the actual value of the particle size is less than or equal to the maximum particle size error value δ. If it is not satisfied, the classifying motor speed, the pulverizer motor speed, the induced draft fan motor speed and the feeder motor speed are adjusted in sequence according to the priority of the operating process parameters, using the positive or reverse search method, until the particle size meets the system production requirements. While meeting the particle size, in order to improve the production efficiency of the air flow pulverizing device, according to the influence of the classifying motor speed, the pulverizer motor speed, the induced draft fan motor speed and the feeder motor speed on the output of qualified materials, the positive search and reverse search methods are respectively used. Such adjustment not only meets the fineness requirements of the particle size, but also optimizes the production capacity, thereby greatly shortening the on-site commissioning time, enabling the material to quickly reach the qualified particle size, reducing the waste of materials, and meeting the optimal production capacity.

[0049] The above is an example of the best implementation of the present invention, and the parts not described in detail are common knowledge of ordinary technicians in the field. The protection scope of the present invention shall be based on the content of the claims, and any equivalent transformation based on the technical enlightenment of the present invention is also within the protection scope of the present invention.

Claims

1. A method for controlling the particle size and capacity of a jet milling device, characterized in that: Step 1: According to the process design requirements of the airflow pulverizing device, set the given value range of the inverter corresponding to the classifier motor, pulverizer motor, induced draft fan motor and feeder motor, and set the particle size target value r d , and set the target value of particle size r d The maximum particle size error δ between the actual particle size and the actual particle size; Step 2: Start the airflow crushing device and use a dry laser particle size tester to detect the actual value of the particle size of the current output material. d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 3; Step 3: The given value of the first frequency converter controlling the classifier motor adopts the positive sequence search method, and the current given value increases by a fixed step length. The actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 4; Step 4: The given value of the second frequency converter controlling the motor of the pulverizer is searched in reverse order. The current given value is reduced by a fixed step length, and the actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 5; Step 5: The set value of the third frequency converter controlling the induced draft fan motor is searched in reverse order. The current set value is reduced by a fixed step length. The actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise go to step 6; Step 6: The given value of the fourth frequency converter controlling the feeder motor is searched in reverse order. The current given value is reduced by a fixed step length. The actual value of the particle size of the current output material is detected by a dry laser particle size tester. When the target value of the particle size is r d -When the actual value of the particle size is ≤ the maximum particle size error value δ, go to step 7, otherwise return to step 3; Step 7, taking the current given values ​​of the first frequency converter controlling the classifier motor, the second frequency converter controlling the pulverizer motor, the second frequency converter controlling the induced draft fan motor and the fourth frequency converter controlling the feeder motor as the final set values, and terminating the execution of the search program.

2. The method for controlling the particle size and capacity of the air flow pulverizing device according to claim 1, characterized in that: The given value range of the first inverter for initializing the control of the classifier motor is [u min ,u max ], the given value range of the second inverter controlling the grinder motor is [v min ,v max ], the given value range of the third inverter controlling the induced draft fan motor is [w min ,w max ], the given value range of the fourth inverter controlling the feeder motor is [z min ,z max ].

3. The method for controlling the particle size and capacity of the air flow pulverizing device according to claim 2, characterized in that: The forward search method is to search in a fixed step size from small to large within the given value range of the frequency converter; the reverse search method is to search in a fixed step size from large to small within the given value range of the frequency converter.

4. The method for controlling the particle size and capacity of the air flow pulverizing device according to claim 1, characterized in that: Set the system sampling period T=10 seconds.

5. A control system for particle size and capacity of an air flow pulverizing device, used to implement the control method for particle size and capacity of an air flow pulverizing device according to any one of claims 1 to 4, characterized in that: The embedded control system includes an embedded control system connected to an industrial computer via an RS-485 serial port, and a first regulator, a second regulator, a third regulator and a fourth regulator are integrated in the embedded control system; Also includes a first frequency converter, a second frequency converter, a third frequency converter and a fourth frequency converter; The first regulator and the first frequency converter are used to control the classifier motor, the second regulator and the second frequency converter are used to control the crushing motor, the third regulator and the third frequency converter are used to control the induced draft fan motor, and the fourth regulator and the fourth frequency converter are used to control the feeder motor.

6. The particle size and capacity control system of the air flow pulverizing device according to claim 5, characterized in that: Particle size target value r d , the first regulator, the first frequency converter and the classifier motor form a classifier motor speed control loop; The classifier motor speed control loop is based on the particle size target value r d The positive sequence search method is used to adjust the speed of the classifier motor through the first regulator and the first frequency converter.

7. The particle size and capacity control system of the air flow pulverizing device according to claim 5, characterized in that: Particle size target value r d , the second regulator, the second frequency converter and the pulverizer motor form a pulverizer motor speed control loop; The motor speed control circuit of the pulverizer is based on the target particle size r d The motor speed of the pulverizer is adjusted by the second regulator and the second frequency converter according to the reverse search method.

8. The particle size and capacity control system of the air flow pulverizing device according to claim 5, characterized in that: Particle size target value r d , the third regulator, the third frequency converter and the induced draft fan motor form an induced draft fan motor speed control loop; The induced draft fan motor speed control loop is based on the particle size target value r d The reverse search method is used to adjust the speed of the induced draft fan motor through the third regulator and the third frequency converter.

9. The particle size and capacity control system of the air flow pulverizing device according to claim 5, characterized in that: Particle size target value r d , the fourth regulator, the fourth frequency converter and the feeder motor form a feeder motor speed control loop; The feeder motor speed control circuit is based on the particle size target value r d And the reverse search method, through the fourth regulator and the fourth frequency converter, to adjust the amount of material entering the crusher per unit time.

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