A high concentration pulping mill control system and control method

Abstract

The present invention discloses a high-concentration pulping mill control system and control method, comprising a moving disc cylinder, a hydraulic system, a programmable logic controller, a servo driver, a detection module, and a touch screen; the detection module comprises: an encoder, an oil pressure sensor, a displacement sensor, and a temperature sensor; the moving disc cylinder is coaxially arranged with the moving disc drive shaft, the programmable logic controller collects feedback signals from the detection module to perform PID control calculation to close the control hydraulic system to output pressure oil, the servo controls the moving disc cylinder to drive the moving disc to move axially, so as to realize a constant gap between the moving disc and the fixed disc or dynamically adjust the gap, so as to stabilize the pulping forming quality and significantly improve the pulping effect; at the same time, the system also has emergency position holding function, grinding disc wear detection and alarm prompt function, thereby improving the automation level of pulping equipment.

Description

Technical Field

[0001] The invention relates to the technical field of grinding disc machines, and in particular to a high-concentration beating mill control system and a control method. Background Art

[0002] Refining is a key link in the utilization of biomass waste resources and plant fiber pulping process. The selection of automated and precisely controlled refining production equipment is a way to achieve efficient utilization of biomass and plant fibers. At present, most biomass waste resource utilization uses pulpers as the main equipment. For example, current papermaking enterprises, especially those involved in the production of cement bag paper, cigarette paper, high-speed wheel printing paper, etc., mostly use high-concentration pulping equipment. High-concentration pulping equipment mainly relies on the mutual friction, extrusion, kneading and twisting of high-concentration pulp between the grinding discs to refine the fibers, so that the fibers become twisted and curled, with high shrinkage capacity, retaining the length and strength of the fibers, and rarely increasing the components of fine fibers. It can greatly improve the shrinkage rate and toughness of paper, and the paper is strong, tough, and has high burst resistance. However, the existing high-concentration pulping equipment has poor control accuracy of the spacing between the pulp mill discs, outdated control technology or direct manual adjustment, resulting in unstable product quality and low production efficiency. For example, when supplying raw materials to the pulper, there is a situation where the raw material input amount is not constant, and there is also the problem of load changes when different types of raw materials are input. At this time, the equipment cannot adaptively adjust the grinding disc gap in real time according to the feed amount and load changes, nor can it control the grinding disc spacing to remain constant. Therefore, the grinding disc is affected by the feed and load, resulting in a short service life of the grinding disc and serious interference with the uniformity and stability of the pulp quality. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a high-concentration pulping mill control system that can continuously, stably and accurately control the spacing between grinding discs, thereby making the pulping quality controllable and extending the life of the grinding discs.

[0004] The present invention is achieved through the following technical solutions: a high-concentration pulping mill control system, including a moving plate cylinder, a hydraulic system, a programmable logic controller, a servo drive, a detection module, and a touch screen; wherein, the moving plate cylinder is a double-rod cylinder, the two chambers have equal effective areas, and is a constant-speed cylinder, the moving plate cylinder piston rod and the main shaft connecting the moving plate and the drive motor are integrated, when working, the fixed plate remains fixed relative to the moving plate, the moving plate is driven to rotate by the motor, and the hydraulic system controls the moving plate cylinder to adjust the distance between the moving plate and the fixed plate.

[0005] The hydraulic system includes: a hydraulic oil tank, a hydraulic pump, a servo motor, a pressure gauge, a relief valve, a reversing valve, a second reversing valve, and a stop valve. The servo motor drives the hydraulic pump to absorb oil from the hydraulic oil tank and output pressure oil to the reversing valve. The pressure pipeline in front of the reversing valve is also connected to a relief valve and a pressure gauge. The A and B ports of the reversing valve are respectively connected to the two oil chambers A' and B' of the moving disc oil cylinder. A stop valve is also provided in the pipeline between the A' oil chamber and the B' oil chamber. The return oil of the reversing valve and the drain oil of the relief valve are connected back to the oil tank. The reversing valve can switch the pressure oil to output to any one of the two oil chambers A' and B' of the moving disc oil cylinder. A second reversing valve is also provided between the reversing valve and the A' chamber of the moving disc oil cylinder. The second reversing valve has the function of one-way sealing of the A' chamber.

[0006] The setting of the overflow valve can protect the hydraulic system pressure from exceeding the maximum set pressure, and overflow the pressure oil to unload it, including the sudden increase in oil pressure transmitted to the moving disc cylinder when the load increases during the operation of the moving disc, which can also be overflowed and unloaded. The stop valve is in a closed state when the equipment is working normally. When the equipment, hydraulic system or moving disc is repaired / adjusted, the stop valve can be opened to connect the two oil chambers of the moving disc cylinder to make the moving disc drive shaft float axially.

[0007] The programmable logic controller is the core of the control calculation. The programmable logic controller collects the signals from the detection module for processing and calculation, and outputs signals to the reversing valve and servo driver to control the servo motor. The servo motor drives the hydraulic pump to output flow and control oil pressure.

[0008] The detection module includes: an encoder, an oil pressure sensor, a second oil pressure sensor, a displacement sensor, and a temperature sensor; wherein the encoder is arranged on the servo motor, collects the encoder output signal and transmits it to the programmable logic controller, the oil pressure sensor is arranged at the pump outlet, collects the oil pressure signal of the oil pressure sensor and transmits it to the programmable logic controller, the second oil pressure sensor is arranged in the pipeline between the second reversing valve and the A' cavity of the moving plate cylinder, the second oil pressure sensor collects the oil pressure signal and transmits it to the programmable logic controller, the displacement sensor is arranged on the moving plate cylinder, and is used to detect the displacement of the piston rod of the moving plate cylinder, and collects the displacement signal of the displacement sensor to the programmable logic controller.

[0009] The touch screen is the input and display module of the system, which can display and input the distance between the moving plate and the fixed plate, the wear of the grinding plate, the displacement sensor setting data of the moving plate, the oil pressure, the oil pressure of the A' cavity, the oil pump speed, the servo torque, the feed rate, the tool setting parameters, and the alarm parameters. The touch screen can realize manual debugging and automatic operation, and has the function of displaying / beeping alarms when random variables exceed the preset values ​​during operation.

[0010] The high-concentration pulping mill control system inputs the initial setting data through the touch screen, and displays the process parameters and alarm prompts through the touch screen. The programmable logic controller + servo driver is used as the control module to control the output power of the hydraulic system, and the feedback data of the detection module is collected for PID adjustment and then enters the cycle control, thus forming a closed-loop control system.

[0011] The driving shaft of the moving plate is provided with a lubrication system, and the bearing part of the driving motor main shaft is provided with a temperature sensor for collecting the shaft temperature rise / too low for early warning. The shaft temperature signal of the temperature sensor can be collected and transmitted to the programmable logic controller.

[0012] Another object of the present invention is to provide a control method for high-concentration pulping equipment based on the above system, which method realizes automatic control and adjustment of the spacing between the grinding discs of the pulping machine, and the steps are as follows.

[0013] Step 1: Preset the distance between the moving plate and the fixed plate according to the feed material and feed amount through the touch screen input, set the oil pressure, hydraulic pump speed and feed amount during initial use, set the limit values ​​of each sensor parameter, and set the emergency hold trigger parameters of the second oil pressure sensor and displacement sensor signals.

[0014] Step 2, tool alignment before work. Before starting work, it is necessary to control the moving disc and the fixed disc to align the tool closely to determine the spacing reference between the moving disc and the fixed disc and adjust the working clearance of the cutter disc. Specifically, the servo motor is controlled to output low-pressure and low-flow hydraulic oil to the A' chamber of the moving disc cylinder, so that the moving disc slowly approaches and presses against the fixed disc. The programmable logic controller determines the starting reference by receiving the pressure increase-maintaining signal parameters of the second oil pressure sensor and the displacement change record-maintaining signal parameters of the displacement sensor, and the system automatically memorizes the initial position parameters; then the moving disc cylinder is automatically / manually positioned to the grinding disc spacing setting position: the programmable logic controller receives the displacement signal of the displacement sensor, and outputs the control signal to the servo driver to control the servo motor and the hydraulic pump to rotate and output the pressure oil. The pressure oil is switched and output to the A' / B' chamber of the moving disc cylinder through the reversing valve controlled by the programmable logic controller. The displacement of the piston rod of the moving disc cylinder drives the moving disc to adjust the gap with the fixed disc.

[0015] Step 3, the equipment inputs and supplies raw materials to the grinding disc, the moving disc is driven to rotate by the motor, the hydraulic pump is driven to rotate by the servo motor to output pressure oil to the reversing valve, the reversing valve controls the action of the moving disc cylinder, the displacement sensor detects the displacement signal and transmits it back to the programmable logic controller, the programmable logic controller calculates and determines the large / small distance between the moving disc and the fixed disc and the set displacement deviation, outputs a signal to the reversing valve, controls the reversing valve to switch the oil supply to the moving disc cylinder, when it is necessary to increase the distance between the moving disc and the fixed disc, the reversing valve switches to input pressure oil into the B' chamber, controls the moving disc cylinder to move in the direction of the driving motor, and returns oil to the A' chamber until it is infinitely close to the displacement sensor setting value of the moving disc, and then the programmable logic controller controls the reversing valve to input pressure oil The A' chamber and the B' chamber return oil. At this time, the programmable logic controller detects the feedback signal of the displacement sensor and the oil pressure sensor, and then calculates and outputs the torque and speed signals to the servo motor. The speed of the servo motor is fed back to the programmable logic controller through the encoder again, and the PID adjustment calculation is performed with the real-time feedback displacement sensor data and oil pressure sensor data. The programmable logic controller outputs the signal to the servo driver again to control the operation of the servo motor. The servo motor outputs torque and controls the speed, controls the hydraulic pump to output the hydraulic flow and pressure in proportion, keeps the distance between the moving plate and the fixed plate within the controllable range, and the hydraulic system pressure is displayed by the pressure gauge. The relief valve acts as a safety valve to maintain a safe overflow at the highest pressure.

[0016] During normal operation, the force between the moving plate and the fixed plate tends to be stable. When the input raw material supply between the grinding plates increases or decreases, or the material changes, the moving plate will produce displacement deviation, thereby passively causing pressure changes in the oil chamber A' of the moving plate cylinder. The pressure in the oil pressure chamber connected to the oil pressure sensor fluctuates beyond the range. The programmable logic controller adjusts the PID output of the corresponding control signal to the servo driver to control the servo motor based on the feedback signal of the oil pressure sensor and the feedback signal of the displacement sensor, and controls and adjusts the output torque and speed, so that the driving hydraulic pump is converted into precise pressure and flow hydraulic power output to the moving plate cylinder, and finally controls the distance between the moving plate and the fixed plate to be within the optimal output range of the abrasive.

[0017] During normal operation, the programmable logic controller also detects the data signal sent back by the temperature sensor in real time. When the shaft temperature exceeds the normal operating temperature range, it will issue an alarm to the equipment or output a control signal to shut down the equipment.

[0018] Step 4, emergency position maintenance application: the second reversing valve is in the normally open position in the non-emergency state, and has the function of one-way closing the A' chamber in the emergency state. The emergency position state can be switched automatically / manually by the system. When the pressure of the input movable plate cylinder A' chamber decays or becomes unstable, the programmable logic controller determines by detecting the oil pressure signal of the second oil pressure sensor and the oil pressure sensor signal, and controls the reversing switch of the second reversing valve.

[0019] Working condition one: in non-emergency state, the second reversing valve is normally open. The programmable logic controller determines whether the gap between the moving plate and the fixed plate tends to a fixed value by detecting the displacement sensor signal parameters and the second oil pressure sensor signal parameters. If it tends to a fixed value, the output flow of the hydraulic system is basically zero at this time, and the hydraulic pump only provides pressure to maintain torque. The system controls the second reversing valve to one-way close the moving plate cylinder A' chamber according to the setting. The programmable logic controller controls the servo driver to temporarily work and enter the standby state to save energy. When the second oil pressure sensor detects that the oil pressure deviates from the normal working value, the programmable logic controller controls the servo driver to drive the hydraulic pump to work and output oil pressure until the pressure in the moving plate cylinder A' chamber stabilizes and then repeats the energy-saving standby state.

[0020] Working condition two: in a non-emergency state, when the pressure input to the moving disc cylinder A' chamber decays or becomes unstable, the system automatically enters a protection state based on the oil pressure parameter judgment detected by the second oil pressure sensor, and the programmable logic controller controls the second reversing valve to reversingly close the moving disc cylinder A' chamber, and utilizes the higher opening pressure of the one-way valve of the second reversing valve to filter the increased unstable pressure of the system, and utilizes the one-way function of the one-way valve of the second reversing valve to close the A' chamber, thereby preventing the unstable expansion of the grinding disc spacing caused by pressure reduction or decay.

[0021] Working condition three: in emergency state, when abrasive input is abnormal, causing the movable plate retreat distance to expand, passively causing the pressure of the movable plate cylinder A' chamber to overpressure, the system automatically performs safety protection, the programmable logic controller controls the reversal of the second reversing valve, and the A' chamber is connected to the overflow valve to unload. The overpressure parameters are determined by the programmable logic controller based on the oil pressure signal detected by the second oil pressure sensor.

[0022] Step 5, determination of the expiration of the life of the grinding disc: during the first tool alignment after the moving disc is replaced, the displacement sensor detecting the position parameters of the moving disc close to the fixed disc is transmitted to the programmable logic controller for automatic memory and storage; subsequently, during use, each time the system is turned on for the first tool alignment after being shut down, the system automatically compares the tool alignment data of the moving disc and the fixed disc after being turned on with the tool alignment position data of the first time after the moving disc is replaced; when the difference between the two exceeds the set value, that is, the wear is too large and exceeds the thickness life of the moving disc, the system issues an alarm to indicate the end of its life and reminds you to replace the grinding disc.

[0023] The beneficial effects of the present invention are as follows: the servo-adjusted actuator adopts a moving plate cylinder to control the axial displacement adjustment of the moving plate and the gap between the fixed plate, the piston rod of the moving plate cylinder is integrated with the moving plate drive shaft, and the hydraulic pressure output by the moving plate cylinder directly acts on the moving plate, reducing unnecessary disturbance of the force transmission components and making the control more precise; the moving plate cylinder also adopts a double-acting dual-output shaft constant-velocity cylinder structure, and the feed and retract hydraulic flow can be directly achieved by switching the reversing valve, simplifying the hydraulic system structure and eliminating the need for flow readjustment. The moving plate cylinder is also provided with a displacement sensor for detecting the displacement of the moving plate drive shaft, which can detect and output the change signal of the spacing between the moving plate and the fixed plate in real time, and the system is also provided with a second reversing valve for maintaining the pressure in the A' chamber of the moving plate cylinder, and the pressure monitoring sensor of the A' chamber of the moving plate cylinder is input into the programmable logic controller to realize emergency position maintenance. The high-concentration pulping mill control system adopts hydraulic control, which has the advantages of high precision, good controllability, large output force value, and unlimited application range of the machine model; the touch screen is used as the human-computer interaction, which can optimize the operability in the application process, and collects the main monitoring and control signals such as shaft temperature, oil pressure, and servo motor speed, and feeds them back to the programmable logic controller and servo controller for PID control calculation. The control signal outputs torque and speed to the servo motor to form a closed-loop control, and realizes continuous and stable dynamic disc servo adjustment, which ultimately stabilizes the pulping forming quality and significantly improves the pulping effect; at the same time, the system also has the function of grinding disc wear detection and alarm prompt, which improves the automation level of pulping equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the composition and working principle of the control system of the present invention;

[0025] Figure 2 It is a control flow diagram of the present invention;

[0026] Figure 3 It is a block diagram of the functional modules of the present invention.

[0027] In the figure, 1-hydraulic oil tank, 2-hydraulic pump, 3-encoder, 4-servo motor, 5-servo driver, 6-pressure gauge, 7-overflow valve, 8-oil pressure sensor, 9-reversing valve, 10-stop valve, 11-moving disc cylinder, 12-programmable logic controller, 13-touch screen, 14-displacement sensor, 15-temperature sensor, 16-lubrication station, 17-moving disc, 18-fixed disc, 19-second reversing valve, 20-second oil pressure sensor. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] like Figure 1-3A high-concentration pulping mill control system includes a moving disc cylinder 11, a hydraulic system, a programmable logic controller 12, a servo driver 5, a detection module, and a touch screen 13; wherein the moving disc cylinder 11 is a double-rod cylinder with equal effective areas of two chambers, and is a constant-speed cylinder. The piston rod of the moving disc cylinder 11 and the main shaft connecting the moving disc 17 and the driving motor are integrated. When working, the fixed disc 18 remains fixed relative to the moving disc 17, and the moving disc 17 is driven to rotate by the motor. The hydraulic system controls the moving disc cylinder 11 to adjust the distance between the moving disc 17 and the fixed disc 18; the hydraulic system includes: a hydraulic oil tank 1, a hydraulic pump 2, a servo motor 4, a pressure gauge 6, a relief valve 7, a reversing valve 9, a second reversing valve 19, and a stop valve 10. The servo motor 4 drives the hydraulic pump 2 to suck oil from the hydraulic oil tank 1 and output the pressure oil to the reversing valve 9. The pressure pipeline in front of the reversing valve 9 is also connected with an overflow valve 7 and a pressure gauge 6. The A and B ports of the reversing valve 9 are respectively connected to the A' and B' oil chambers of the moving disc cylinder. A stop valve 10 is also provided in the pipeline between the A' oil chamber and the B' oil chamber. The return oil of the reversing valve 9 and the drain oil of the overflow valve 7 are connected back to the oil tank. The reversing valve 9 can switch the pressure oil to output to any one of the oil chambers on both sides of the moving disc cylinder 11. A second reversing valve 19 is also provided between the reversing valve 9 and the A chamber of the moving disc cylinder 11. The second reversing valve 19 has the function of one-way closing the A' chamber.

[0030] The programmable logic controller 12 is the core of the control calculation. The programmable logic controller 12 processes and calculates the signals collected by the detection module, and outputs signals to the reversing valve 9, the second reversing valve 19 and the servo driver 5. The servo driver 5 controls the servo motor 4 to drive the hydraulic pump 2 for flow output and oil pressure control. The detection module includes: an encoder 5, an oil pressure sensor 8, a second oil pressure sensor 20, a displacement sensor 14, and a temperature sensor 15; wherein, the encoder 5 is arranged on the servo motor 4, and the output signal of the encoder 5 is collected to the programmable logic controller 12; the oil pressure sensor 8 is arranged at the pump outlet, and the oil pressure signal of the oil pressure sensor 8 is collected to the programmable logic controller 12; the second oil pressure sensor 20 is arranged in the pipeline between the second reversing valve 19 and the movable plate cylinder 11A' cavity, and the oil pressure signal of the second oil pressure sensor is collected and transmitted to the programmable logic controller 12; the displacement sensor 14 is arranged on the movable plate cylinder 11, and is used to detect the displacement of the piston rod of the movable plate cylinder 11, and the displacement signal of the displacement sensor 14 is collected to the programmable logic controller 12; the bearing part of the driving motor main shaft is provided with a temperature sensor 15, and the shaft temperature signal of the temperature sensor 15 is collected to the programmable logic controller 12. The input and display module is a touch screen 13, which can display and input the distance between the moving plate 17 and the fixed plate 18, the wear amount of the grinding plate, the displacement sensor setting data of the moving plate, the oil pressure, the oil pump speed, the feed amount, the tool setting parameters, and the alarm parameters. The touch screen can realize manual debugging and automatic operation, and has the function of displaying / beeping alarms when random variables exceed the preset values ​​during operation.

[0031] The present invention implements a high-concentration pulping mill control method according to the above system, and the steps are as follows:

[0032] Step 1: According to the feed material and feed amount, pre-set the distance between the moving plate 17 and the fixed plate 18 through the touch screen 13 input, set the oil pressure and the speed and feed amount of the hydraulic pump 2 during initial use, set the limit values ​​of each sensor parameter, and set the emergency hold trigger parameters of the second oil pressure sensor 20 and the displacement sensor 14 signals.

[0033] Step 2, tool alignment before work. Before starting work, it is necessary to control the moving disc 17 and the fixed disc 18 to be close to each other for tool alignment, so as to determine the spacing reference between the moving disc 17 and the fixed disc 18 and adjust the working clearance of the cutter disc. Specifically, the servo motor 4 is controlled to output low-pressure and low-flow hydraulic oil to the A' chamber of the moving disc cylinder 11, so that the moving disc 17 slowly approaches and is close to the fixed disc 18. The programmable logic controller 12 determines the starting reference by receiving the pressure rise-maintaining signal parameters of the second oil pressure sensor 20 and the displacement change record-maintaining signal parameters of the displacement sensor 14, and the system automatically memorizes the initial position parameters; then the moving disc cylinder 11 is automatically / manually positioned to the grinding disc spacing setting position: the programmable logic controller 12 receives the displacement signal of the displacement sensor 14, and outputs the control signal to the servo driver 5 to control the servo motor 4 and the hydraulic pump 2 to rotate and output the pressure oil. The pressure oil is switched and output to the A' / B' chamber of the moving disc cylinder 11 through the reversing valve 9 controlled by the programmable logic controller 12. The displacement of the piston rod of the moving disc cylinder 11 drives the moving disc 17 to adjust the gap with the fixed disc 18.

[0034] Step 3, the equipment inputs and supplies raw materials to the grinding disc space, the moving disc 17 is driven to rotate by the motor, the hydraulic pump 2 is driven to rotate by the servo motor 4 to output pressure oil to the reversing valve 9, the reversing valve 9 controls the moving disc cylinder 11 to move, the displacement sensor 14 detects the displacement signal and transmits it back to the programmable logic controller 12, the programmable logic controller 12 calculates and determines whether the distance between the moving disc 17 and the fixed disc 18 is large / small and has a set displacement deviation, outputs a signal to the reversing valve 9, controls the reversing valve 9 to switch the oil supply to the moving disc cylinder 11, when it is necessary to increase the distance between the moving disc 17 and the fixed disc 18, the reversing valve 9 switches to input the pressure oil into the B' chamber, controls the moving disc cylinder 11 to move in the direction of the driving motor, and the A' chamber returns the oil until it is infinitely close to the displacement sensor 14 setting value of the moving disc 17, and then the programmable logic controller 12 controls the reversing valve 9 to switch .... The oil enters the A' chamber and returns to the B' chamber. At this time, the programmable logic controller 12 detects the feedback signal of the displacement sensor 14 and the feedback signal of the oil pressure sensor 8, and then calculates and outputs the torque and speed signal to the servo motor 4. The speed of the servo motor 4 is fed back to the programmable logic controller 12 again through the encoder 3, and the PID adjustment calculation is performed with the real-time feedback data of the displacement sensor 14 and the data of the oil pressure sensor 8 or the second oil pressure sensor 20. The programmable logic controller 12 outputs a signal to the servo driver 5 again to control the operation of the servo motor 4. The servo motor 4 outputs torque and controls the speed, controls the hydraulic pump 2 to output the hydraulic flow and pressure in proportion, keeps the distance between the moving plate 17 and the fixed plate 18 within the controllable range, and the hydraulic system pressure is displayed by the pressure gauge. The relief valve 7 acts as a safety valve to maintain a safe overflow at the highest pressure.

[0035] During normal operation, the force between the moving plate 17 and the fixed plate 18 tends to be stable. When the input raw material supply between the grinding plates increases or decreases, or the material changes, the moving plate 17 will produce a displacement deviation, thereby passively causing a pressure change in the A' oil chamber of the moving plate cylinder 11. The pressure in the oil pressure chamber connected to the oil pressure sensor 8 fluctuates beyond the range. The programmable logic controller 12 PID adjusts and outputs a corresponding control signal to the servo driver 5 to control the servo motor 4 based on the feedback signal of the oil pressure sensor 8 and the feedback signal of the displacement sensor 14, and controls and adjusts the output torque and speed, thereby converting the driving hydraulic pump 2 into precise pressure and flow hydraulic power output to the moving plate cylinder 11, and finally controlling the distance between the moving plate 17 and the fixed plate 18 to be within the optimal output range of the abrasive.

[0036] During normal operation, the programmable logic controller 12 also detects the data signal sent back by the temperature sensor 15 in real time. When the shaft temperature exceeds the normal operating temperature range, it will issue an alarm to the equipment or output a control signal to shut down the equipment.

[0037] Step 4, emergency position maintenance application: the second reversing valve 19 is normally open in non-emergency state, and has the function of one-way closing A' chamber in emergency state. The emergency position state can be switched automatically / manually by the system. When the pressure of the input movable plate cylinder 11A' chamber decays or becomes unstable, the programmable logic controller 12 determines by detecting the oil pressure signal of the second oil pressure sensor 20 and the oil pressure sensor 8 signal, and controls the reversing switch of the second reversing valve 19.

[0038] Working condition one: in non-emergency state, the second reversing valve 19 is in the normally open position, and the programmable logic controller 12 determines whether the gap between the moving plate 17 and the fixed plate 18 tends to a fixed value by detecting the signal parameters of the displacement sensor 14 and the signal parameters of the second oil pressure sensor 20. If it tends to a fixed value, the output flow of the hydraulic system is basically zero at this time, and the hydraulic pump 2 only provides pressure to maintain the torque. The system controls the second reversing valve 19 to switch to a one-way closed moving plate cylinder 11A' chamber according to the setting. The programmable logic controller 12 controls the servo driver 5 to temporarily stop working and enter the standby state to save energy. When the second oil pressure sensor 20 detects that the oil pressure deviates from the normal working value, the programmable logic controller 12 controls the servo driver 5 to drive the hydraulic pump 2 to work and output the oil pressure until the pressure in the moving plate cylinder 11A' chamber stabilizes and then repeats the energy-saving standby state.

[0039] Working condition two, in a non-emergency state, when the pressure input to the moving disc cylinder A' chamber decays or becomes unstable, the system automatically enters a protection state based on the oil pressure parameter judgment detected by the second oil pressure sensor 20, and the programmable logic controller 12 controls the second reversing valve 19 to reversingly one-way close the moving disc cylinder 11A' chamber, and utilizes the higher opening pressure of the one-way valve of the second reversing valve 19 to filter the increased unstable pressure of the system, and utilizes the one-way function of the one-way valve of the second reversing valve 19 to close the A' chamber, thereby preventing the unstable expansion of the grinding disc spacing caused by pressure reduction or decay.

[0040] Working condition three, in emergency state, when abrasive input is abnormal, causing the retreat distance of the movable plate 17 to expand, passively causing the pressure of the movable plate cylinder 11A' chamber to overpressure, the system automatically performs safety protection, the programmable logic controller 12 controls the reversal of the second reversing valve 19, and the A' chamber is connected to the overflow valve 7 to unload, and the overpressure parameter is determined by the programmable logic controller 12 based on the oil pressure signal detected by the second oil pressure sensor 20.

[0041] Step 5, determination of the expiration of the life of the grinding disc: during the first tool alignment after the moving disc 17 is replaced, the displacement sensor 14 of the moving disc 17 close to the fixed disc 18 detects position parameters and transmits them to the programmable logic controller 12 for automatic memory and storage. During subsequent use, each time the system is turned on for the first time after being shut down for tool alignment, the system automatically compares the tool alignment data of the moving disc 17 and the fixed disc 18 after being turned on with the tool alignment position data of the first time after the moving disc 17 is replaced. When the difference between the two exceeds the set value, that is, the amount of wear is too large and exceeds the thickness life of the moving disc, the system issues an alarm to indicate the end of its life and reminds you to replace the grinding disc.

Claims

1. A high-concentration pulping mill control method, comprising: A movable disc cylinder (11), a hydraulic system, a programmable logic controller (12), a detection module, and a touch screen (13), characterized in that: it also includes a servo driver (5), the hydraulic system is connected to the A' and B' chambers of the movable disc cylinder (11), and the direction of the servo output oil pressure / flow is switchable to the A' or B' chamber of the movable disc cylinder (11), and the displacement of the movable disc cylinder (11) adjusts the grinding disc spacing, the detection module is composed of pressure, speed, and displacement sensors, which are respectively installed at the monitoring point of the control system, the output end of the detection module is connected to the input end of the programmable logic controller (12), the output end of the programmable logic controller (12) is connected to the input end of the servo driver (5), and the touch screen (13) is connected to the programmable logic controller (12) for input and output of setting data; The movable plate oil cylinder (11) is a constant speed double-rod cylinder with equal action area, and the main shaft connecting the movable plate (17) and the drive motor is integrated with the piston rod of the movable plate oil cylinder (11); The hydraulic system comprises a servo motor (4), a hydraulic pump (2), a reversing valve (9), a relief valve (7), and a second reversing valve (19); the servo motor is connected to drive the hydraulic pump to output pressure oil, and is connected to the reversing valve and the relief valve via a pressure pipeline; the second reversing valve (19) is arranged between the reversing valve (9) and the A' cavity of the movable plate oil cylinder (11), and a one-way valve is arranged inside the valve, which has the function of one-way sealing the A' cavity of the movable plate oil cylinder; The detection module comprises a displacement sensor (14) arranged on the movable plate cylinder (11), a temperature sensor (15) arranged on the drive shaft of the movable plate (17), an oil pressure sensor (8) arranged on the pump port pipeline of the hydraulic system, a second oil pressure sensor (20) arranged between the second reversing valve (19) and the A' chamber of the movable plate cylinder (11), and an encoder (3) arranged on the servo motor (4); The hydraulic system further comprises a stop valve (10) connecting the two chambers of the movable plate cylinder (11); The following control methods are used: Step 1: According to the feed material and feed amount, the distance between the moving plate (17) and the fixed plate (18) is preset through the touch screen (13), the oil pressure and the speed and feed amount of the hydraulic pump (2) are set during initial use, the limit values ​​of each sensor parameter are set, and the emergency hold trigger parameters of the second oil pressure sensor (20) and the displacement sensor (14) signals are set; Step 2, tool alignment before work. Before starting work, the moving disc (17) and the fixed disc (18) need to be controlled to be close to each other for tool alignment, so as to determine the spacing reference between the moving disc (17) and the fixed disc (18) and adjust the working clearance of the cutter disc. Specifically, the servo motor (4) is controlled to output low-pressure and low-flow hydraulic oil to the A' chamber of the moving disc cylinder (11), so that the moving disc (17) slowly approaches and is close to the fixed disc (18). The programmable logic controller (12) determines the start of the tool alignment by receiving the pressure rise-maintaining signal parameter of the second oil pressure sensor (20) and the displacement change record-maintaining signal parameter of the displacement sensor (14). The system automatically memorizes the initial position parameters; then the movable plate cylinder (11) is automatically / manually positioned to the grinding plate spacing setting position: the programmable logic controller (12) receives the displacement signal of the displacement sensor (14), outputs the control signal to the servo driver (5) to control the servo motor (4) and the hydraulic pump (2) to rotate and output the pressure oil, and the pressure oil is switched and output to the A' / B' chamber of the movable plate cylinder (11) through the reversing valve (9) controlled by the programmable logic controller (12), and the piston rod of the movable plate cylinder (11) is displaced to drive the movable plate (17) to adjust the gap with the fixed plate (18); Step 3, the equipment inputs raw materials into the grinding disc space, the moving disc (17) is driven to rotate by the motor, the hydraulic pump (2) is driven to rotate by the servo motor (4) to output pressure oil to the reversing valve (9), the reversing valve (9) controls the moving disc cylinder (11) to move, the displacement sensor (14) detects the displacement signal and transmits it back to the programmable logic controller (12), the programmable logic controller (12) calculates and determines whether the distance between the moving disc (17) and the fixed disc (18) is large / small and has a set displacement deviation, outputs a signal to the reversing valve (9), controls the reversing valve (9) to switch the oil supply to the moving disc cylinder (11), when it is necessary to increase the distance between the moving disc (17) and the fixed disc (18), the reversing valve (9) switches to allow the pressure oil to enter the 'B chamber, controls the moving disc cylinder (11) to move The driving motor moves in the direction of rotation, and the A' chamber returns oil until it is infinitely close to the set value of the displacement sensor (14) of the moving plate (17). Then, the programmable logic controller (12) controls the reversing valve (9) to change the direction so that the pressure oil is input into the A' chamber and the B' chamber returns oil. At this time, the programmable logic controller (12) detects the feedback signal of the displacement sensor (14) and the feedback signal of the oil pressure sensor (8), and then calculates and outputs the torque and speed signal to the servo motor (4). The speed of the servo motor (4) is fed back to the programmable logic controller (12) again through the encoder (3), and PID adjustment calculation is performed with the real-time feedback data of the displacement sensor (14) and the data of the oil pressure sensor (8) or the second oil pressure sensor (20). The programmable logic controller (12) outputs a signal to the servo driver (5) again to control the operation of the servo motor (4). The servo motor (4) outputs torque and controls the speed, controls the hydraulic pump (2) to output hydraulic flow and pressure in proportion, keeps the distance between the moving plate (17) and the fixed plate (18) within a controllable range, and the pressure of the hydraulic system is displayed by a pressure gauge. The relief valve (7) serves as a safety valve to maintain a safe overflow under the highest pressure. During normal operation, the force between the moving plate (17) and the fixed plate (18) tends to be stable. When the input supply of raw materials between the grinding plates increases or decreases, or the material changes, the moving plate (17) will produce displacement deviation, thereby passively forming a pressure change in the oil chamber A' of the moving plate cylinder (11). The pressure in the oil pressure chamber connected to the oil pressure sensor (8) is In the case of fluctuations beyond the range, the programmable logic controller (12) outputs corresponding control signals to the servo driver (5) to control the servo motor (4) through PID adjustment according to the feedback signals from the oil pressure sensor (8) and the displacement sensor (14), and controls and adjusts the output torque and speed, thereby converting the driving hydraulic pump (2) into precise pressure and flow hydraulic power output to the moving plate cylinder (11), and finally controlling the distance between the moving plate (17) and the fixed plate (18) to be within the optimal abrasive output range; during normal operation, the programmable logic controller (12) also detects the data signal sent back by the temperature sensor (15) in real time, and when the shaft temperature exceeds the normal operating temperature range, it will issue an alarm to the equipment or output a control signal to shut down the equipment; Step 4, emergency position holding application: the second reversing valve (19) is in a normally open position in a non-emergency state, and has a one-way closing function of the A' chamber in an emergency state. The emergency position state can be switched automatically / manually by the system. When the pressure input to the A' chamber of the movable plate cylinder (11) decays or becomes unstable, the programmable logic controller (12) determines by detecting the oil pressure signal of the second oil pressure sensor (20) and the oil pressure sensor (8), and controls the reversing switch of the second reversing valve (19); Step 5, determining the expiration of the grinding disc life: during the first tool alignment after the moving disc (17) is replaced, the displacement sensor (14) of the moving disc (17) close to the fixed disc (18) detects position parameters and transmits them to the programmable logic controller (12) for automatic memory storage. During subsequent use, each time the system is turned off and then turned on for tool alignment for the first time, the system automatically compares the tool alignment data of the moving disc (17) and the fixed disc (18) after startup with the tool alignment position data of the first time after the moving disc (17) is replaced. When the difference between the two exceeds the set value, that is, the wear is too large and exceeds the thickness life of the moving disc, the system issues an alarm to indicate the end of its life and reminds you to replace the grinding disc.

2. A high-concentration beating mill control method according to claim 1, characterized in that: The step 4 specifically includes: working condition 1, in a non-emergency state, the second reversing valve (19) is in a normally open position, the programmable logic controller (12) determines whether the gap between the moving plate (17) and the fixed plate (18) tends to a fixed value by detecting the signal parameters of the displacement sensor (14) and the signal parameters of the second oil pressure sensor (20). If it tends to a fixed value, the output flow of the hydraulic system is basically zero at this time, and the hydraulic pump (2) only provides pressure to maintain the torque. The system controls the second reversing valve (19) to switch the one-way closing of the A' chamber of the moving plate cylinder (11) according to the setting judgment, and the programmable logic controller (12) controls the servo driver (5) to temporarily work and enter a standby state, thereby saving energy. When the second oil pressure sensor (20) detects that the oil pressure deviates from the normal working value, the programmable logic controller (12) controls the servo driver (5) to drive the hydraulic pump (2) to work and output the oil pressure until the pressure of the A' chamber of the moving plate cylinder (11) is stable and then the energy-saving standby state is repeated; working condition 2, in a non-emergency state, when When the pressure input into the cavity A' of the movable disc oil cylinder decays or becomes unstable, the system automatically enters a protection state according to the oil pressure parameter determined by the second oil pressure sensor (20), and the programmable logic controller (12) controls the second reversing valve (19) to reversing and one-way closing the cavity A' of the movable disc oil cylinder (11). By utilizing the higher opening pressure of the one-way valve of the second reversing valve (19) to filter the unstable pressure increased by the system, the one-way function of the one-way valve of the second reversing valve (19) is utilized to close the cavity A', thereby preventing the unstable expansion of the grinding disc spacing caused by the pressure reduction or decay. Working condition three: in an emergency state, when the abrasive input is abnormal, the retraction spacing of the movable disc (17) is expanded, and the pressure of the cavity A' of the movable disc oil cylinder (11) is passively over-pressured. The system automatically performs safety protection, and the programmable logic controller (12) controls the second reversing valve (19) to reversing, and the cavity A' is connected to the overflow valve (7) to unload. The over-pressure parameter is determined according to the oil pressure signal detected by the second oil pressure sensor (20) and transmitted to the programmable logic controller (12).

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