A powder classification and conveying control method for powder processing

Abstract

This invention discloses a powder classification and conveying control method for powder processing, applicable to direct-connection classifier operation in pneumatic conveying of powders. It collects the outlet pressure of the conveying pipe and the inlet pressure of the classifier to calculate the pressure difference before and after the inlet, and also collects the load signal of the classifier wheel drive. A pressure difference judgment dead zone threshold group is set, and the start and end points of the post-plug suction suppression window are determined based on continuous judgment of the pressure difference before and after the inlet. The number of continuous judgments at the start point is determined by converting the length of the expansion section and the material plug passage time, while the number of continuous judgments at the end point is formed by superimposing the sampled number on the conversion result to create an asymmetric counting aperture. Within the post-plug suction suppression window, a suction suppression intensity marker is generated based on the minimum pressure difference before and after the inlet and the range of the classifier wheel drive load signal, and a classifier wheel speed control command sequence is generated to prevent separated coarse powder from being drawn back into the classification area and causing a short-term coarsening of the product particle size.

Description

Technical Field

[0001] This invention relates to the field of powder process control technology, and more specifically, to a powder classification and conveying control method for powder processes. Background Technology

[0002] Powder process control technology is commonly used in powder classification and conveying scenarios. Existing technologies typically collect pressure signals such as the outlet pressure of the conveying pipe and the inlet pressure of the classifier, and calculate the pressure difference between the two. Simultaneously, they collect the classifier wheel drive load signal as a reference for operating status, and then adjust, maintain, or reduce the classifier wheel speed based on changes in pressure difference and load. Some solutions also employ filtering, threshold judgment, or fixed delay methods to suppress the impact of instantaneous fluctuations on control decisions and maintain the basic stability of the classification process.

[0003] The existing technology has the following shortcomings:

[0004] On the one hand, when the material plug formed by the pneumatic conveying of powder enters the expansion section and reaches the tail stage, the obstruction of gas flow causes the pressure release at the outlet of the conveying pipe to be asynchronous with the pressure drop in the inlet of the classifier. The pressure difference before and after the inlet is prone to change from positive to negative and may fluctuate near zero. If the speed reduction is triggered simply based on the pressure drop or the sign of the pressure difference, the defense capability is easily weakened when the back suction trend appears, causing the separated coarse powder to be rolled back into the classification area and causing the product particle size to coarsen temporarily. On the other hand, under the condition that the pressure difference changes temporarily or fluctuates near zero due to the continuous arrival of the material plug, the classifier wheel drive load signal is easily affected by non-back suction factors. Existing solutions are difficult to distinguish between back suction trends and non-back suction disturbances and maintain a stable and consistent control diameter. At the same time, fixed delay methods are difficult to adaptively adjust with changes in the length of the expansion section, the material plug passage time, and the degree of pressure relief lag, which can easily lead to insufficient defense or control stagnation. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a powder classification and conveying control method for powder processing, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A powder classification and conveying control method for powder processing includes:

[0008] S101: Collect the outlet pressure of the conveying pipe and the inlet pressure of the classifier, calculate the pressure difference before and after the inlet, and collect the classifier wheel drive load signal; when the pressure difference before and after the inlet is continuously negative and reaches the starting point of the continuous judgment number, take the starting sampling point of the continuous interval that meets the condition as the starting point of the post-plug suction suppression window; when the pressure difference before and after the inlet is continuously non-negative and reaches the ending point of the continuous judgment number, take the starting sampling point of the continuous interval that meets the condition as the ending point of the post-plug suction suppression window; wherein, the starting point of the continuous judgment number is determined by converting the length of the expanded diameter connection section and the material plug passage time, and the ending point of the continuous judgment number is obtained by superimposing the superimposed sampling number determined by the material plug pressure relief hysteresis characteristic value on the basis of the conversion result, and the ending point of the continuous judgment number is greater than the starting point of the continuous judgment number; within the post-plug suction suppression window, a suction suppression intensity mark is generated based on the minimum value of the pressure difference before and after the inlet and the range of the classifier wheel drive load signal;

[0009] S102, Read the post-plug suction suppression window and suction suppression intensity mark, generate a series of graded wheel speed control commands, including speed increase command, speed hold command, and speed decrease command, wherein the speed increase range is determined by the suction suppression intensity mark, and the speed decrease process is executed according to the duration corresponding to the number of consecutive determinations at the end point;

[0010] S103, output the stage wheel speed control command sequence to the stage wheel drive and execute it; during the execution of the speed drop command, when the pressure difference before and after the inlet is negative again and the number of consecutive determinations at the starting point is reached, terminate the current speed drop command and return to S101 to redetermine the new post-thrombus suction suppression window.

[0011] In a preferred embodiment, the expansion connection section is an expansion transition pipe section connecting the outlet of the conveying pipe and the inlet of the classifier. The outlet pressure of the conveying pipe is the static pressure arranged at the outlet of the conveying pipe, and the inlet pressure of the classifier is the static pressure arranged in the inlet of the classifier. The pressure difference before and after the inlet is the outlet pressure of the conveying pipe minus the inlet pressure of the classifier. When the pressure difference before and after the inlet is negative, it indicates that the inlet pressure of the classifier is higher than the outlet pressure of the conveying pipe.

[0012] In a preferred embodiment, the pressure at the outlet of the delivery pipe and the pressure at the inlet of the classifier are respectively subjected to moving average filtering before the pressure difference before the inlet is calculated. The length of the filtering window is the preset number of pressure filtering sampling points, and the preset number of pressure filtering sampling points is less than the number of consecutive judgments at the starting point. A pressure difference judgment dead zone threshold group is set, including a negative dead zone threshold and a positive dead zone threshold. The negative dead zone threshold is less than 0 and the positive dead zone threshold is greater than 0. When the pressure difference before and after the inlet is not greater than the negative dead zone threshold, it is judged as continuous negative. When the pressure difference before and after the inlet is not less than the positive dead zone threshold, it is judged as continuous non-negative. When the pressure difference before and after the inlet is between the negative dead zone threshold and the positive dead zone threshold, the judgment result of the previous sampling time is used to count the number of consecutive judgments at the starting point and the number of consecutive judgments at the ending point.

[0013] In a preferred embodiment, the graded wheel drive load signal is selected from either the torque-related current component or the active power signal of the graded wheel drive motor; a moving average filter is performed on the graded wheel drive load signal, the filter window length is a preset number of filter sampling points, and the preset number of filter sampling points is less than the number of consecutive judgments at the starting point; the continuous interval is the set of sampling times that continuously meet the same judgment condition at adjacent sampling times; the post-thrust suppression window is the pressure sampling sequence interval defined by the starting point and the ending point of the post-thrust suppression window.

[0014] In a preferred embodiment, the material plug passage time is determined as follows: The pressure signal with the largest variation in pressure between the outlet pressure of the conveying pipe and the inlet pressure of the classifier is used as the identification object. The time difference between the starting moment of the continuous rise and the starting moment of the subsequent continuous fall is taken as the material plug passage time. Continuous rise refers to the interval where the pressure value does not decrease point by point between adjacent sampling moments, and continuous fall refers to the interval where the pressure value does not increase point by point between adjacent sampling moments. The sampling period is a preset fixed sampling period, and the material plug passage time is converted according to the sampling period to obtain the baseline passage sampling number. The number of consecutive starting point determinations is determined by converting the baseline passage sampling number and a preset starting point coefficient. The number of consecutive ending point determinations is the sum of the results obtained by converting the baseline passage sampling number and the preset ending point coefficient, plus the material plug pressure relief hysteresis characteristic value. The number of superimposed samples is determined, and the preset starting point coefficient is less than 1 and the preset ending point coefficient is greater than 1. The hysteresis characteristic value of the pressure relief valve is used to characterize the degree of asynchrony between the pressure drop at the outlet of the conveying pipe and the pressure drop at the inlet of the classifier. The hysteresis characteristic value of the pressure relief valve is determined in the following way: the starting moment when the pressure difference before and after the inlet changes from positive to negative is taken as the starting point of the hysteresis calculation. The pressure drop rate at the outlet of the conveying pipe and the pressure drop rate at the inlet of the classifier are calculated separately within the preset slope window, and the hysteresis characteristic value of the pressure relief valve is determined based on the difference or ratio of the two drop rates. The number of superimposed samples is determined by the hysteresis characteristic value of the pressure relief valve, and the number of superimposed samples does not decrease when the hysteresis characteristic value of the pressure relief valve increases. The duration corresponding to the number of consecutive determinations of the endpoint is the duration obtained by converting the number of consecutive determinations of the endpoint according to the sampling period.

[0015] In a preferred embodiment, the suction suppression intensity is marked as an ordered scalar value, generated by combining a differential pressure reversal dimension index and a load fluctuation dimension index. The differential pressure reversal dimension index is determined based on the deviation of the minimum differential pressure before and after the inlet within the post-suction suppression window from a preset delivery pressure benchmark. The preset delivery pressure benchmark is the average of the delivery pipe outlet pressures corresponding to a preset number of sampling times before the start of the post-suction suppression window. The load fluctuation dimension index is determined based on the deviation of the range of the stage wheel drive load signal within the post-suction suppression window from a preset drive load benchmark. The preset drive load benchmark is the average of the stage wheel drive load signals corresponding to a preset number of sampling times before the start of the post-suction suppression window. The differential pressure reversal dimension index and the load fluctuation dimension index are weighted and combined according to preset weights to obtain the suction suppression intensity mark, and the weight corresponding to the differential pressure reversal dimension index is greater than the weight corresponding to the load fluctuation dimension index.

[0016] In a preferred embodiment, a maximum protection duration is set, which is longer than the duration corresponding to the number of consecutive determinations at the endpoint. When the timing starts from the beginning of the post-thrust suction suppression window and the maximum protection duration has not yet reached the number of consecutive determinations at the endpoint due to a continuously non-negative pressure difference before and after the inlet, the time corresponding to the maximum protection duration is determined as the endpoint of the post-thrust suction suppression window. When the endpoint of the post-thrust suction suppression window is determined by the maximum protection duration, the speed drop process is executed according to the duration corresponding to the maximum protection duration.

[0017] In a preferred embodiment, the speed increase command is used to adjust the target speed of the grading wheel to a level not lower than the target speed most recently issued before the start of the post-suppression window; the speed increase range is the speed increment added based on the most recently issued target speed; the suppression intensity mark and the speed increase range satisfy a monotonic correspondence, and when the suppression intensity mark increases, the speed increase range does not decrease.

[0018] In a preferred embodiment, the speed reduction command is implemented by generating a target speed sequence that decreases according to the sampling period; when the end point of the post-thrust suppression window is determined by the number of consecutive end point determinations, the number of decrease steps in the target speed sequence is equal to the number of consecutive end point determinations; when the end point of the post-thrust suppression window is determined by the maximum protection duration, the number of decrease steps in the target speed sequence is equal to the count obtained by converting the maximum protection duration according to the sampling period; the target speed after the target speed sequence decreases returns to the target speed most recently issued before the start point of the post-thrust suppression window; if there is no most recently issued target speed, it returns to the preset reference target speed.

[0019] In a preferred embodiment, during the execution of the speed reduction command, when the pressure difference before and after the inlet becomes continuously negative again and reaches the number of consecutive determinations at the starting point, the current speed reduction command is canceled and the remaining execution of the target speed sequence is terminated, and the process returns to S101 to redetermine a new post-thrombus suction suppression window.

[0020] The effects and advantages of the powder classification and conveying control method for powder processing according to the present invention are as follows:

[0021] This invention provides a powder classification and conveying control method for powder processing. By filtering pressure and load signals and introducing a pressure difference judgment dead zone threshold group, combined with continuous judgment of the pressure difference before and after the inlet, the method ensures that even when the pressure difference fluctuates near zero during continuous arrival of the feed plug, it is less likely to falsely trigger the boundary. This reduces the risk of speed reduction caused by misjudgment of pressure drop and avoids insufficient defense leading to short-term coarsening of product particle size. Furthermore, the number of consecutive judgments at the starting point is determined by converting the length of the expansion section and the feed plug passage time. The number of consecutive judgments at the end point is formed by superimposing the superimposed sampling number determined by the pressure relief hysteresis characteristic value of the feed plug on the conversion result to form an asymmetric counting caliber. This allows the boundary of the back suction stage to be adaptively adjusted according to changes in operating conditions, reducing insufficient defense or control stagnation caused by fixed delays that are too short or too long. Moreover, within the post-pump suction suppression window, the minimum pressure difference before and after the inlet and the load range are used to generate a suction suppression intensity mark to determine the speed increase range. If the pressure difference before and after the inlet becomes negative again during the fall period and reaches the starting continuous judgment count, the fall is terminated and the window determination is restarted, thereby reducing the defense gap under repeated back suction conditions. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0023] Figure 2 This is a schematic diagram of step S101 of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention provides a powder classification and conveying control method for powder processing, applicable to powder classification and conveying control in direct-connection pneumatic conveying of powder to a classifier. When the material plug formed by pneumatic conveying enters the expansion section, gas flow is obstructed, causing the pressure release at the conveying pipe outlet to be asynchronous with the pressure drop at the classifier inlet. The pressure difference before and after the inlet easily changes from positive to negative at the tail of the material plug and fluctuates near zero. Furthermore, the classifier drive load signal is easily interfered with by non-backflow factors, making it difficult to distinguish between backflow trends and non-backflow disturbances, leading to a temporary coarsening of the product particle size. The material plug consists of segmented high-solid-concentration powder agglomerates, and the expansion section is an expansion transition pipe connecting the conveying pipe outlet and the classifier inlet.

[0026] Therefore, the technical problem to be solved by this invention is: under the condition that the continuous arrival of the material plug causes the differential pressure to change for a short time or fluctuate near zero and the load signal is easily interfered with by non-backflow factors, how to establish a backflow stage boundary judgment and speed control caliber that is not sensitive to noise and can adapt to changes in the length of the expansion section, the material plug passage time, and the degree of material plug pressure relief lag, so as to avoid insufficient defense caused by pressure drop triggering deceleration or insufficient defense and control stagnation caused by fixed delay deviation.

[0027] Based on the above design, this invention constructs a complete process for a powder classification and conveying control method for powder processing, consisting of steps S101 to S103 sequentially. (Refer to...) Figure 1 , Figure 1 This is a schematic diagram of the method flow of the present invention, which includes:

[0028] Step S101, determining the post-plug suction suppression window and generating a suction suppression intensity mark, is used during the access sensing stage of the reverse flow condition at the tail of the plug. Based on the asymmetric continuous counting of the pressure difference sign before and after the inlet, the post-plug suction suppression window is determined, and a suction suppression intensity mark is generated within this window. This step reads the conveyor pipe outlet pressure input set X101, the classifier inlet chamber pressure input set X102, the classifier wheel drive load signal input set X103, and the parameter configuration set X104, and outputs the post-plug suction suppression window state set R101 for step S102 to read and generate the classifier wheel speed control command sequence. X101 provides the sampling sequence of the static pressure at the conveyor pipe outlet, and X102 provides the sampling sequence of the static pressure within the classifier inlet chamber. Both are used to calculate the pressure difference before and after the inlet and to complete the sign determination and continuous counting accordingly. X103 provides the sampling sequence of the classifier wheel drive load signal, used to calculate the load range within the post-plug suction suppression window and participate in the generation of the suction suppression intensity mark. X104 is used to provide the calculation and judgment criteria for this step, and is used to constrain sampling and filtering, differential pressure sign determination, continuous count conversion of start and end points, depressurization hysteresis calculation window, end point fallback protection duration, and the benchmark and weight settings for the suction suppression intensity mark. The R101 field group category includes at least the window boundary group, the continuous judgment subarray of start and end points, the superimposed sampling array, the depressurization hysteresis characteristic value group, and the suction suppression intensity mark group. The continuous judgment subarray of start and end points adopts an asymmetric counting caliber for the start and end points to resist the jitter near zero differential pressure and cover the end point tailing caused by depressurization hysteresis. When a post-thrust suction suppression window is not formed in this step, a corresponding identifier is given in R101 and step S102 is degraded to generate the speed control command result set R102 according to a conservative caliber.

[0029] Step S102 generates speed control commands. Based on the determination of the post-aperture suction suppression window and the generation of suction suppression intensity markers in step S101, this step generates a sequence of graded wheel speed control commands. This command sequence includes at least a speed increase command, a speed hold command, and a speed decrease command, thus providing a directly executable and revocable countermeasure for step S103. This step reads the post-aperture suction suppression window state set R101 and the parameter configuration set X104, determines the speed increase magnitude based on the suction suppression intensity markers, and generates a target speed sequence that decreases according to the sampling period based on the decrease duration corresponding to the end of the window. The resulting speed control command result set R102 is then read by step S103. Among them, R101 at least carries the start point of the post-thrust suction suppression window, the end point of the post-thrust suction suppression window, the duration of the fall, and the suction suppression intensity mark; X104 at least carries the sampling period, the preset benchmark target speed, and the speed increase mapping caliber; R102 is used to carry the target speed of the increase segment, the target speed of the maintenance segment, and the target speed sequence and the number of decrease steps of the fall segment, so as to uniformly define the anti-trajectory trajectory and exit rhythm of the graded wheel within the post-thrust suction suppression window.

[0030] Step S103, "Instruction Execution and Reversal Restart," outputs the classifier wheel speed control instruction sequence generated in step S102 to the classifier wheel drive for execution. During the execution of the speed reversal instruction, if the pressure difference before and after the inlet is continuously negative again, reaching the starting point for the consecutive determination count, the speed reversal cancellation process is triggered, and the process returns to step S101. This ensures that the control flow can promptly restart the window determination when encountering new material plug impact during the reversal phase. This step reads the speed control instruction result set R102, the post-plug suction suppression window status set R101, and the conveying pipe outlet pressure input set X101 and the classifier inlet cavity pressure input set X102. It reuses the pressure difference determination caliber from step S101 to perform sign determination and continuous counting on the pressure difference before and after the inlet. The starting point for the consecutive determination count is taken from R101 to maintain consistency in the reversal threshold source. This step does not generate a new static result set; its output is the issuance of the classifier wheel target speed and the process jump when the reversal condition is met.

[0031] The implementation process and operational effects of the method of the present invention will be described in detail below with reference to specific embodiments. It should be understood that the embodiments are only used to illustrate the technical solution of the present invention, and not to limit it. Without changing the essence of the invention, the relevant steps, parameters and module divisions can be appropriately adjusted.

[0032] In an optional embodiment, the implementation process of step S101 includes: generating the differential pressure determination caliber, determining the number of consecutive determinations of the start and end points and the number of superimposed samples, determining the window boundary and the maximum protection duration as a fallback, and generating the absorption suppression intensity marker. (Refer to...) Figure 2 , Figure 2 This is a schematic diagram of step S101 of the present invention.

[0033] In the generation of the differential pressure determination caliber, the outlet pressure of the delivery pipe and the inlet pressure of the classifier are both static pressure sampling values ​​at corresponding locations. The differential pressure before and after the inlet is calculated by subtracting the inlet pressure of the classifier from the outlet pressure of the delivery pipe. A negative differential pressure before and after the inlet indicates that the inlet pressure of the classifier is higher than the outlet pressure of the delivery pipe. Moving average filtering is performed on X101 and X102 according to a preset number of pressure filtering sampling points before calculating the differential pressure before and after the inlet. Moving average filtering is performed on X103 according to a preset number of load filtering sampling points. Both the preset number of pressure filtering sampling points and the preset number of load filtering sampling points are limited to less than the starting number of consecutive determinations. Subsequently, a pressure difference determination dead zone threshold group is introduced, including a negative dead zone threshold and a positive dead zone threshold. The negative dead zone threshold is less than 0 and the positive dead zone threshold is greater than 0. When the pressure difference before and after the inlet is not greater than the negative dead zone threshold, it is determined to be continuous and negative. When the pressure difference before and after the inlet is not less than the positive dead zone threshold, it is determined to be continuous and non-negative. When the pressure difference before and after the inlet is between the negative dead zone threshold and the positive dead zone threshold, the determination result of the previous sampling time is used for subsequent continuous counting.

[0034] In determining the number of consecutive start and end point determinations and the number of superimposed samples, the material plug passage time is first determined and the baseline passage sample number is calculated. The pressure signal with the larger variation amplitude in X101 and X102 is used as the identification object. The time difference between the starting moment of the continuous rise and the starting moment of the subsequent continuous fall is taken as the material plug passage time. Continuous rise refers to the interval where the pressure value does not decrease point by point between adjacent sampling moments, and continuous fall refers to the interval where the pressure value does not increase point by point between adjacent sampling moments. The sampling period is provided by X104 and is a preset fixed sampling period. The length of the expanded diameter connection section is provided by X104 or pre-fixed by the equipment installation record. The number of consecutive start point determinations is determined by converting the baseline passage sample number and the preset start point coefficient, where the preset start point coefficient is less than 1. The baseline term for the number of consecutive end point determinations is determined by converting the baseline passage sample number and the preset end point coefficient, where the preset end point coefficient is greater than 1. To obtain the number of superimposed samples, the starting moment when the pressure difference before and after the inlet changes from positive to negative is taken as the starting point for hysteresis calculation. Within the preset slope window, the pressure drop rate at the outlet of the conveying pipe and the pressure drop rate at the inlet of the classifier are calculated respectively. The hysteresis characteristic value of the slug is determined based on the difference or ratio of the two drop rates. The number of superimposed samples is then determined by the hysteresis characteristic value of the slug and superimposed on the benchmark item of the number of consecutive determinations at the endpoint, and the number of superimposed samples does not decrease when the hysteresis characteristic value of the slug increases.

[0035] In the window boundary determination and maximum protection duration fallback, a continuous interval is defined as the set of sampling times that continuously meet the same determination condition in adjacent sampling times. When the pressure difference before and after the inlet is continuously negative and reaches the starting point of the continuous determination count, the starting sampling point of the continuous interval that meets this condition is taken as the starting point of the post-thrombosis suppression window. When the pressure difference before and after the inlet is continuously non-negative and reaches the ending point of the continuous determination count, the starting sampling point of the continuous interval that meets this condition is taken as the ending point of the post-thrombosis suppression window. To avoid control stagnation caused by the end point condition not appearing for a long time, a maximum protection duration is set, and the maximum protection duration is longer than the duration corresponding to the number of consecutive determinations at the end point. When the timer starts from the starting point of the post-thrombosis suppression window and the maximum protection duration has not reached the number of consecutive determinations at the end point, the time corresponding to the maximum protection duration is determined as the ending point of the post-thrombosis suppression window. The duration corresponding to the number of consecutive determinations at the end point is calculated by converting the number of consecutive determinations at the end point according to the sampling period, and is written into R101 together with the maximum protection duration for step S102 to align the caliber of the fallback process. When the pressure difference before and after the inlet is continuously negative within the observation interval corresponding to the passage time of the self-material plug, and the number of consecutive judgments at the starting point is not reached, it is determined that no post-plug suction suppression window has been formed. No new post-plug suction suppression window start point and post-plug suction suppression window end point are generated. Only the number of consecutive judgments at the starting point and the number of consecutive judgments at the end point, as well as the maximum protection time, are written into R101 and the suction suppression intensity flag is set to zero so that step S102 can generate a graded wheel speed control command sequence according to the conservative caliber degradation.

[0036] In the generation of the suction suppression intensity marker, the minimum value of the pressure difference before and after the inlet and the range of the staged wheel drive load signal are calculated within the post-plug suction suppression window. The minimum value of the pressure difference before and after the inlet is used to form the pressure difference reversal dimension index, and the load range is used to form the load fluctuation dimension index. The pressure difference reversal dimension index is determined based on the deviation of the minimum value of the pressure difference before and after the inlet from the preset delivery pressure benchmark, which is the average outlet pressure of the delivery pipe corresponding to a preset number of sampling times before the start of the post-plug suction suppression window. The load fluctuation dimension index is determined based on the deviation of the load range from the preset drive load benchmark, which is the average of the staged wheel drive load signal corresponding to a preset number of sampling times before the start of the post-plug suction suppression window. The two indices are weighted and combined according to preset weights to obtain the suction suppression intensity marker, and the weight corresponding to the pressure difference reversal dimension index is greater than the weight corresponding to the load fluctuation dimension index. Finally, the start and end points of the post-bolt suction suppression window, the number of consecutive judgments at the start and end points, the material flow time, the reference flow sampling number, the material pressure relief hysteresis characteristic value, the number of superimposed samples, the maximum protection duration, and the suction suppression intensity flag are written into the post-bolt suction suppression window state set R101.

[0037] To facilitate implementation and standardize calculation methods, this embodiment provides a set of optional formulaic methods, and explains the meaning of key parameters within the sentences. The sampling period is denoted as... The unit is seconds, preset and fixed by the parameter configuration set X104. The length of the expanded diameter connection section is denoted as... The unit is meters, provided by X104 or fixed in the equipment installation record. The measurement object used to limit the passage time of the plug is the process of the plug passing through the enlarged diameter connection section, and the conversion parameters are recalibrated when the enlarged diameter connection section is modified or its length is changed. The passage time of the plug is denoted as... The unit is seconds. The reference number of passage samples is determined by the time difference between the starting moment of the continuously rising object and the starting moment of the subsequent continuously falling object. This is used to map the passage process to a sampling scale of continuous counting, for example, by... Rounded down to the nearest integer.

[0038] The preset starting point coefficient is denoted as The value is provided by X104 and is less than 1; the example uses 0.2 because the starting point needs to be established faster to reduce trigger latency. The number of consecutive checks of the starting point is denoted as... Example by Confirmed. The preset endpoint coefficient is denoted as... The value is provided by X104 and is greater than 1; the example uses 1.2 because the endpoint needs more robust confirmation to reduce premature exits. The baseline term for the number of consecutive endpoint determinations is denoted as... Example by This setting ensures that the endpoint count is greater than the starting count at the baseline level. The preset slope window duration is denoted as... The unit is seconds, provided by X104. The starting moment when the pressure difference across the inlet changes from positive to negative is used as the starting point for the lag calculation, and the lag starting moment is denoted as... The rate of pressure drop at the outlet of the delivery pipe within the lag window is denoted as... The unit is Pascals per second. Examples are provided below. Calculation, where Indicates time The filtered value of the delivery pipe outlet pressure. The rate of pressure drop in the classifier inlet cavity within the hysteresis window is denoted as... The unit is Pascals per second. Examples are provided. Calculation, where Indicates time The pressure filter value of the classifier inlet cavity. The characteristic value of the pressure relief hysteresis of the feed plug is denoted as... Used to quantify the degree of asynchronous pressure drop between the two paths, example by... Take the difference value. The hysteresis gain coefficient is denoted as... , provided by X104 and non-negative, is taken as 1 in the example, to maintain linearity and ease of tuning. The number of superimposed samples is denoted as . Example by Round down to the nearest integer, and set the endpoint to the number of consecutive determinations. to satisfy When it increases The monotonicity constraint does not decrease. The duration corresponding to the number of consecutive endpoint determinations is denoted as... The unit is seconds, and the example is as follows: The calculated value is used to align with the aperture for the maximum protection duration and written into R101 for use in step S102.

[0039] The minimum pressure difference before and after the inlet within the post-thrombus suction suppression window is denoted as: The range of the graded wheel drive load signal is denoted as The preset delivery pressure reference is denoted as... Its value is the average outlet pressure of the delivery pipe corresponding to a preset number of sampling times before the start of the post-suction suppression window, and the preset number is given by X104. The preset drive load reference is denoted as Its value is the average of the graded wheel drive load signal at a preset number of sampling times before the start of the post-thrust suppression window, where the preset number is given by X104. The differential pressure reversal dimension is marked as... Example by Calculation. Load fluctuation dimension is denoted as... Example by Calculation. Preset weights are denoted as... and Provided by X104 and satisfying Example and The reason for this is that the suction suppression intensity is primarily driven by the reversal of the pressure difference before and after the inlet, while the load serves as an auxiliary dimension to suppress occasional disturbances. The suction suppression intensity is denoted as... Example by The combination yields the desired result.

[0040] In an optional embodiment, the implementation process of step S102 includes basic reference anchoring and adjustment magnitude determination, three-segment instruction alignment construction, fallback sequence generation and endpoint source compatibility, and result writing and undoing index caliber solidification.

[0041] In determining the base reference anchoring and the upward adjustment range, the most recently issued target speed before the start of the suction suppression window after the bolt is selected as the base reference. The most recently issued target speed is obtained from the target speed setpoint cache of the stage wheel drive. When the most recently issued target speed does not exist, the preset benchmark target speed in parameter configuration set X104 is used as the base reference. Subsequently, the suction suppression intensity flag in R101 is read, and the speed upward adjustment range is determined according to the monotonic mapping caliber in X104. This ensures that the speed upward adjustment range does not decrease when the suction suppression intensity flag increases, and that the speed upward adjustment range is non-negative, thereby adjusting the target speed of the stage wheel to be no lower than the base reference by the speed upward adjustment command.

[0042] In the construction of the three-segment instruction alignment, the starting point of the post-bolt suction suppression window given by R101 is used as the trigger time of the speed increase instruction. The target speed of the stage wheel is adjusted from the basic reference to the high target speed after the basic reference is superimposed with the speed increase amplitude. The interval from the starting point to the ending point of the post-bolt suction suppression window is set as the effective interval of the speed holding instruction, so that the target speed of the stage wheel remains unchanged at the high target speed within this interval, thereby ensuring that the adjustment segment and the holding segment correspond one-to-one with the post-bolt suction suppression window in time.

[0043] In the process of generating a fallback sequence compatible with the endpoint source, the fallback process is executed according to the duration corresponding to the number of decreasing steps given in R101. The duration is calculated by converting the number of decreasing steps according to the sampling period, and a target speed sequence decreasing according to the sampling period is generated accordingly. When R101 indicates that the endpoint of the post-thrust suppression window is determined by the number of consecutive endpoint determinations, the number of decreasing steps is taken as the number of consecutive endpoint determinations, and a decreased target speed is issued in each sampling period, so that the target speed smoothly falls back from the high target speed to the base reference. When R101 indicates that the endpoint of the post-thrust suppression window is determined by the maximum protection duration, the number of decreasing steps is taken as the count obtained by converting the maximum protection duration according to the sampling period, and the target speed sequence is generated in the same way. To ensure the feasibility of decreasing according to the sampling period, in this embodiment, the control command issuance period and the sampling period adopt the same caliber, both based on the sampling period given by X104.

[0044] In the result writing and cancellation index caliber fixing process, the base reference, high-order target speed, decrease step count, target speed sequence, and fallback duration are written into R102, so that step S103 can directly output and execute the target speed sequence point by point according to R102. At the same time, to support the feasibility requirements of speed fallback cancellation processing, the sequence position caliber used to locate the range of target speeds that have not yet been executed is fixed in R102, and the number of steps currently executed in the fallback segment is initialized to zero, so that step S103 can stop outputting the target speeds that have not yet been executed when cancellation is triggered and keep the target speed issued at the time of cancellation unchanged.

[0045] When R101 indicates that no post-thrust suppression window was formed or the suppression intensity mark was set to zero, this step degenerates to generate R102 according to a conservative approach, so that the speed increase is zero, and the duration of the holding segment and the fall segment is zero and the target speed sequence of the fall segment is not generated, thereby avoiding unnecessary speed disturbances.

[0046] To facilitate implementation and standardize calculation methods, this embodiment provides a set of optional formulaic methods, with the meaning of symbols and the reasons for example values ​​given within the sentences. The basic reference target rotational speed is denoted as... Its value is the target rotational speed most recently issued before the start of the post-aperture suction suppression window; if it does not exist, the preset benchmark target rotational speed in X104 is used. The suction suppression intensity is denoted as... It is a non-negative ordered scalar and is written to R101 in step S101. The speed increase is denoted as... It is determined by the monotonic mapping aperture given by X104; an example could be a linear limiting mapping. .in For the mapping gain coefficient, an example of 200 revolutions per minute can be used for tuning. To adjust the upper limit of the range, an example of 150 to 300 revolutions per minute can be used, limited by drive capability and process safety boundaries. The high-level target speed is denoted as... ,Depend on Guaranteed The number of decreasing steps is denoted as... Its value is given by R101 and is consistent with the calculation of the fallback duration based on the sampling period. The target rotational speed sequence during the fallback phase is denoted as... It is issued once in each sampling period, and examples can be generated in a linearly decreasing manner. ,in The decrementing step number and to Thus satisfying And ensure a fallback to the base reference. No fallback target speed sequence is generated when the decrease step count is zero. If matching the inverter's minimum adjustment resolution is required, [the following can be done]: Optional processing with minimum step quantization is performed, but the fundamental characteristics of monotonic decline and regression benchmark are not changed.

[0047] In an optional embodiment, the implementation process of step S103 includes instruction sequence execution, differential pressure determination and continuous counting during the fallback period, fallback cancellation processing, and process reversal.

[0048] During instruction sequence execution, the system reads R102 and issues speed increase and speed hold instructions to the graded wheel drive according to the time sequence specified in R102. After entering the fallback phase, it issues the fallback phase target speed sequence point by point according to the sampling period. The fallback phase is identified by the decreasing step number and the fallback phase target speed sequence in R102, which is used to limit the activation interval for canceling monitoring. To ensure revocability, the system maintains the current number of executed steps or sequence position index of the fallback phase during execution, so that when cancellation is triggered, it can locate the decreasing target speed interval in the fallback phase target speed sequence that has not yet been executed.

[0049] In the differential pressure determination and continuous counting during the fallback period, the system only enables cancellation monitoring during the fallback phase and resets the continuously negative count to zero at the start of the fallback phase. Subsequently, X101 and X102 are synchronously collected in each sampling cycle, and the differential pressure determination criteria in step S101 are reused to generate the sign determination result of the differential pressure before and after the inlet. The differential pressure determination criteria include at least the filtering processing of pressure samples, the determination rules corresponding to the differential pressure determination dead zone threshold group, and the rule of using the determination result of the previous sampling time in the dead zone. Based on this, the sampling points where the differential pressure before and after the inlet is continuously negative again are counted. The number of continuous determinations at the starting point is provided by R101 and serves as the continuous counting threshold. R101 and R102 in this execution correspond to the same wheel throttle back suction suppression window determination result, which is used for fallback cancellation trigger determination.

[0050] In the fallback cancellation process, the system compares the consecutive negative count with the number of consecutive determinations at the starting point in R101. When the pressure difference before and after the inlet becomes consecutively negative again, reaching the number of consecutive determinations at the starting point, the system determines that the speed fallback cancellation trigger condition is met and immediately executes the speed fallback cancellation process. The speed fallback cancellation process includes stopping the output of the decreasing target speed after the currently executed step in the target speed sequence of the fallback segment in R102, preventing the issuance of any unexecuted decreasing target speeds, and maintaining the target speed of the tiered wheel at the target speed issued at the time of cancellation trigger, thereby avoiding the continuation of the predetermined fallback rhythm when a new round of reverse pressure trend occurs.

[0051] During the process reversal, after completing the speed drop cancellation process, the system terminates the current step and returns to step S101, redetermines a new post-throttle suction suppression window, and generates a new R101 so that the subsequent step S102 can reconstruct the speed control command sequence under the new window caliber. If R101 reading fails or no R101 corresponding to the current R102 is found, the system returns to step S101 to complete R101 generation or matching before entering the subsequent execution process, to ensure that the cancellation threshold source is consistent with the continuous counting caliber.

[0052] The above formulas are optional calculation methods used to describe conversion relationships; each preset parameter is given by parameter configuration set X104 and can be adjusted according to working conditions.

[0053] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0054] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and inventive constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0055] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0056] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0057] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A powder classification and conveying control method for powder processing, characterized in that, include: S101, collects the outlet pressure of the delivery pipe and the inlet pressure of the classifier, calculates the pressure difference before and after the inlet, and collects the classifier drive load signal; When the pressure difference before and after the inlet is continuously negative and reaches the starting point of the continuous judgment count, the starting sampling point of the continuous interval that meets this condition is taken as the starting point of the post-plug suction suppression window; when the pressure difference before and after the inlet is continuously non-negative and reaches the ending point of the continuous judgment count, the starting sampling point of the continuous interval that meets this condition is taken as the ending point of the post-plug suction suppression window; wherein, the starting point of the continuous judgment count is determined by the conversion between the length of the expanded diameter connection section and the material plug passage time, and the ending point of the continuous judgment count is obtained by superimposing the superimposed sampling number determined by the material plug pressure relief hysteresis characteristic value on the basis of the conversion result, and the ending point of the continuous judgment count is greater than the starting point of the continuous judgment count; within the post-plug suction suppression window, the suction suppression intensity mark is generated based on the minimum value of the pressure difference before and after the inlet and the range of the stage wheel drive load signal; S102, Read the post-plug suction suppression window and suction suppression intensity mark, generate a series of graded wheel speed control commands, including speed increase command, speed hold command, and speed decrease command, wherein the speed increase range is determined by the suction suppression intensity mark, and the speed decrease process is executed according to the duration corresponding to the number of consecutive determinations at the end point; S103, output the stage wheel speed control command sequence to the stage wheel drive and execute it; during the execution of the speed drop command, when the pressure difference before and after the inlet is negative again and the number of consecutive determinations at the starting point is reached, terminate the current speed drop command and return to S101 to redetermine the new post-thrombus suction suppression window.

2. The powder classification and conveying control method for powder processing according to claim 1, characterized in that, The expansion connection section is an expansion transition pipe section that connects the outlet of the conveying pipe and the inlet of the classifier. The outlet pressure of the conveying pipe is the static pressure located at the outlet of the conveying pipe, and the inlet pressure of the classifier is the static pressure located inside the inlet of the classifier. The pressure difference before and after the inlet is the outlet pressure of the conveying pipe minus the inlet pressure of the classifier. When the pressure difference before and after the inlet is negative, it indicates that the inlet pressure of the classifier is higher than the outlet pressure of the conveying pipe.

3. The powder classification and conveying control method for powder processing according to claim 1, characterized in that, The pressure at the outlet of the delivery pipe and the pressure at the inlet of the classifier are respectively subjected to moving average filtering before the pressure difference before the inlet is calculated. The length of the filtering window is the preset number of pressure filtering sampling points, and the preset number of pressure filtering sampling points is less than the number of consecutive judgments at the starting point. A pressure difference judgment dead zone threshold group is set, including a negative dead zone threshold and a positive dead zone threshold. The negative dead zone threshold is less than 0 and the positive dead zone threshold is greater than 0. When the pressure difference before and after the inlet is not greater than the negative dead zone threshold, it is judged as continuous and negative. When the pressure difference before and after the inlet is not less than the positive dead zone threshold, it is judged as continuous and non-negative. When the pressure difference before and after the inlet is between the negative dead zone threshold and the positive dead zone threshold, the judgment result of the previous sampling time is used to count the number of continuous judgments at the starting point and the number of continuous judgments at the ending point.

4. The powder classification and conveying control method for powder processing according to claim 1, characterized in that, The graded wheel drive load signal is selected from either the torque-related current component or the active power signal of the graded wheel drive motor; a moving average filter is performed on the graded wheel drive load signal, the filter window length is the preset number of filter sampling points, and the preset number of filter sampling points is less than the number of consecutive judgments at the starting point; A continuous interval is a set of sampling times that consecutively satisfy the same judgment condition at adjacent sampling times; The post-embolization inhibition window is the pressure sampling sequence interval defined by the start and end points of the post-embolization inhibition window.

5. A powder classification and conveying control method for powder processing according to claim 1, characterized in that, The material plug passage time is determined as follows: The pressure signal with the largest variation in pressure between the outlet pressure of the conveying pipe and the inlet pressure of the classifier is used as the identification object. The time difference between the starting moment of the continuous rise and the starting moment of the subsequent continuous fall is taken as the material plug passage time. Continuous rise refers to the interval where the pressure value does not decrease at adjacent sampling moments, and continuous fall refers to the interval where the pressure value does not increase at adjacent sampling moments. The sampling period is a preset fixed sampling period. The material plug passage time is converted according to the sampling period to obtain the baseline passage sampling number. The number of consecutive starting point determinations is determined by converting the baseline passage sampling number and the preset starting point coefficient. The number of consecutive endpoint determinations is determined by superimposing the results obtained by converting the baseline passage sampling number and the preset endpoint coefficient, and the superimposed sampling number determined by the hysteresis characteristic value of the material plug unloading. The preset starting point coefficient is less than 1 and the preset endpoint coefficient is greater than 1. The hysteresis characteristic value of the pressure relief valve is used to characterize the degree of asynchrony between the pressure drop at the outlet of the conveying pipe and the pressure drop at the inlet of the classifier. The hysteresis characteristic value of the pressure relief valve is determined in the following way: the starting moment when the pressure difference before and after the inlet changes from positive to negative is taken as the starting point of the hysteresis calculation. The pressure drop rate at the outlet of the conveying pipe and the pressure drop rate at the inlet of the classifier are calculated separately within a preset slope window. The hysteresis characteristic value of the pressure relief valve is determined based on the difference or ratio of the two drop rates. The number of superimposed samples is determined by the hysteresis characteristic value of the throttle unloading, and the number of superimposed samples does not decrease when the hysteresis characteristic value of the throttle unloading increases; the duration corresponding to the number of consecutive endpoint determinations is the duration calculated by converting the number of consecutive endpoint determinations according to the sampling period.

6. A powder classification and conveying control method for powder processing according to claim 5, characterized in that, The suppression intensity is marked as an ordered scalar value, which is generated by combining the differential pressure reversal dimension index and the load fluctuation dimension index. The differential pressure reversal dimension index is determined based on the degree of deviation of the minimum pressure difference before and after the inlet within the post-suppression window from the preset delivery pressure benchmark. The preset delivery pressure benchmark is the average value of the delivery pipe outlet pressure corresponding to a preset number of sampling times before the start of the post-suppression window. The load fluctuation dimension index is determined based on the deviation of the range of the graded wheel drive load signal within the post-thrust suppression window from the preset drive load benchmark. The preset drive load benchmark is the average value of the graded wheel drive load signal corresponding to a preset number of sampling times before the start of the post-thrust suppression window. The pressure difference reversal dimension index and the load fluctuation dimension index are combined according to preset weights to obtain the suppression intensity mark, and the weight corresponding to the pressure difference reversal dimension index is greater than the weight corresponding to the load fluctuation dimension index.

7. A powder classification and conveying control method for powder processing according to claim 5, characterized in that, Set the maximum protection duration, which is greater than the duration corresponding to the number of consecutive judgments at the endpoint; When the timing starts from the beginning of the post-thrust suction suppression window and the maximum protection duration has not yet reached the point where the pressure difference before and after the inlet is continuously non-negative and the number of consecutive judgments reaches the end point, the time corresponding to the maximum protection duration is determined as the end point of the post-thrust suction suppression window; when the end point of the post-thrust suction suppression window is determined by the maximum protection duration, the speed drop process is executed according to the duration corresponding to the maximum protection duration.

8. A powder classification and conveying control method for powder processing according to claim 1, characterized in that, The speed increase command is used to adjust the target speed of the stager wheel to a level no lower than the target speed most recently issued before the start of the post-aperture suction suppression window; the speed increase amount is the speed increment added based on the most recently issued target speed; The suction suppression intensity mark and the speed increase range satisfy a monotonic correspondence; when the suction suppression intensity mark increases, the speed increase range does not decrease.

9. A powder classification and conveying control method for powder processing according to claim 1, characterized in that, The speed reduction command is achieved by generating a target speed sequence that decreases according to the sampling period; when the end point of the post-aperture suppression window is determined by the number of consecutive end point determinations, the number of decreasing steps of the target speed sequence is equal to the number of consecutive end point determinations; when the end point of the post-aperture suppression window is determined by the maximum protection duration, the number of decreasing steps of the target speed sequence is equal to the count obtained by converting the maximum protection duration according to the sampling period. After the target speed sequence decreases, the target speed returns to the most recently issued target speed before the start of the post-aperture suppression window. If there is no most recently issued target speed, it returns to the preset benchmark target speed.

10. A powder classification and conveying control method for powder processing according to claim 1, characterized in that, During the execution of the speed reduction command, when the pressure difference before and after the inlet becomes continuously negative again and reaches the number of consecutive determinations at the starting point, the current speed reduction command is canceled and the remaining execution of the target speed sequence is terminated, and the process returns to S101 to redetermine a new post-thrombus suction suppression window.

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