A method and device for dynamic regulation of coal mine grouting relay

Abstract

The application discloses a kind of coal mine grouting relay dynamic adjustment method and device, the method includes: starting stage and adjustment stage, in adjustment stage, according to the current liquid level in buffer tank changes adjustment mode, grout in buffer tank is not in the set liquid level stable range, then enter coarse adjustment mode;If liquid level is in stable range, then enter fine adjustment mode.Micro-adjustment mode includes: constant water level PID regulation, keep liquid level in set value range by PID regulation mode control frequency converter;Pressure PID regulation, adjust outlet control valve opening to make pressure close to set value;Flow is regulated to flow limit value by PID regulation mode control frequency converter;Constant water level PID regulation and the pressure PID regulation described in the said are repeated in turn and circulate.The application effectively solves the application problem that grout cannot be transported in shallow buried depth pipeline in coal mine grouting fire prevention and extinguishing system by switching between adjustment mode, continuous cycle switching between constant water level PID and constant pressure regulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal mine fire prevention and extinguishing, in particular to a coal mine grouting relay dynamic adjustment method and device. BACKGROUND

[0002] According to the relevant requirements of the Coal Mine Safety Regulations, the mine that mines the spontaneous combustion or adopts the top coal caving mining of the spontaneous combustion coal seam must be designed with two or more comprehensive fire prevention and extinguishing measures based on grouting to ensure the safety of coal mine production. At present, for shallow depth coal mines, a fixed grouting station is generally built on the ground by using a single-stage slurry pump. Since the coal seam is shallow, the slurry has a small drop during transportation from the ground to the underground, resulting in a long transportation distance after the mining face extends to a long distance. The lift of the ground grouting station cannot meet the grouting requirements, the flow rate of the slurry in the pipeline is significantly reduced, the outlet pressure is small, the pipeline deposition is serious, the outlet flow is small and pipeline blockage often occurs, which makes it difficult to achieve the ideal effect of fire prevention and extinguishing, and seriously affects the safety of the coal mine.

[0003] To solve the problem of insufficient outlet flow and pressure of the slurry caused by the long multiple lines, the coal mining enterprises usually use the solution of reducing the pipe diameter at the end to increase the flow rate and prevent blockage in the field production. The disadvantage is that the pipe loss is increased, the flow loss is serious, the grouting amount in the fire prevention and extinguishing area is obviously insufficient, and the ground grouting pump is easy to overload. There are also schemes to improve the above-mentioned grouting operation by using slurry pumps, piston pumps, frequency converters and buffer tanks. However, it is found through practice that these improved schemes have serious defects, including being unable to adapt to changes in input flow, slow valve adjustment response, easy to suck air or overflow, and unable to run stably for a long time, etc., which are difficult to be practically applied. SUMMARY

[0004] The present application provides a coal mine grouting relay dynamic adjustment method and device to solve the problems of the prior art, which can maintain the suspension state, output pressure and output flow of the slurry to meet the use requirements of grouting fire prevention and extinguishing, and effectively avoid air suction, overflow and resonance.

[0005] The present application discloses a coal mine grouting relay dynamic adjustment method, comprising:

[0006] Start-up stage: control the outlet control valve to open the outlet pipeline, and control the pressure output device connected with the frequency converter to be opened, so that the slurry in the buffer tank is pressurized and output to the outlet pipeline;

[0007] Adjusting stage: in this stage, the adjusting mode is changed according to the current liquid level in the buffer tank, specifically, if it is detected that the slurry in the buffer tank is not in the set liquid level stable range, the coarse adjusting mode is used to adjust the pressurized output device until the control liquid level is in the liquid level stable range, and then the fine adjusting mode is entered; if the liquid level is in the stable range, the fine adjusting mode is used to adjust the outlet control valve and the pressurized output device until the liquid level is not in the liquid level stable range, and then the coarse adjusting mode is entered;

[0008] The coarse adjusting mode includes: when it is detected that the liquid level exceeds the upper limit or the lower limit of the liquid level stable range, the output frequency of the frequency converter is increased or decreased to approach the liquid level stable range.

[0009] The fine adjusting mode includes:

[0010] Constant liquid level PID adjustment: the frequency converter is controlled by the PID adjustment mode to adjust the liquid level in the buffer tank, which is used to keep the liquid level in the set value range.

[0011] Pressure PID adjustment: the opening degree of the outlet control valve is adjusted to make the pressure of the outlet pipeline approach the pressure set value; due to the adjustment of the opening degree of the outlet control valve, the outlet pipeline flow changes, and the frequency converter is controlled by the PID adjustment mode to adjust the flow of the outlet pipeline, which is used to adjust the flow to the flow limit value.

[0012] The constant liquid level PID adjustment and the pressure PID adjustment are repeated in sequence.

[0013] Further, the starting stage includes:

[0014] When it is detected that the liquid level in the buffer tank continuously rises, the outlet control valve is adjusted to the initial opening degree.

[0015] When it is detected that the liquid level in the buffer tank rises to the set working liquid level height, the frequency converter is controlled to make the slurry pump pressurize the slurry output.

[0016] Further, in the adjusting stage, the coarse adjusting mode specifically includes:

[0017] When the liquid level exceeds the liquid level stable range and rises, the PLC control box controls the frequency converter to increase the output frequency, so that the outlet pipeline flow increases to reduce the liquid level; when the liquid level reduces to the upper limit of the liquid level stable range, the fine adjusting mode is entered;

[0018] When the liquid level exceeds the liquid level stable range and falls, the PLC control box controls the frequency converter to reduce the output frequency, so that the flow of the outlet pipeline reduces to raise the liquid level; when the liquid level rises to the lower limit of the liquid level stable range, the fine adjusting mode is entered.

[0019] Further, in the adjusting stage, the adjusting mode is changed according to the current liquid level in the buffer tank, and the adjusting mode further comprises: when the liquid level in the buffer tank triggers the liquid level switch to reach the limit water level, entering the large rate adjusting mode; and when the liquid level decreases to the limit area, entering the coarse adjusting mode or the fine adjusting mode.

[0020] The large rate adjusting mode comprises: adjusting the output frequency of the frequency converter to a large rate setting value.

[0021] Further, the constant water level PID adjusting comprises:

[0022] The water level control value is used as the setting value, the output frequency of the frequency converter is used as the adjusting value, and the measurement value of the liquid level sensor of the buffer tank is used as the feedback value, and the PID method is used to adjust three cycles to control the liquid level in the liquid level stable range.

[0023] Further, the pressure PID adjusting comprises:

[0024] When the pressure of the outlet pipeline is higher than the setting pressure value, the PLC control box controls the outlet control valve to increase the opening degree until the pressure decreases to the setting pressure value with a difference of the adjusting space value, the outlet control valve stops, the PLC control box adjusts the running frequency value of the frequency converter to decrease, so that the flow decreases to return to the flow limit value before the opening degree of the outlet control valve is increased, and the pressure continues to decrease to the setting pressure value, and the pressure is stably kept at the setting pressure value through three adjusting cycles.

[0025] When the pressure of the outlet pipeline is lower than the setting pressure value, the PLC control box controls the outlet control valve to decrease the opening degree until the pressure increases to the setting pressure value with a difference of the adjusting space value, the outlet control valve stops, the PLC control box adjusts the running frequency value of the frequency converter to increase, so that the flow increases to return to the flow limit value before the opening degree of the outlet control valve is decreased, and the pressure continues to increase to the setting pressure value, and the pressure is stably kept at the setting pressure value through three adjusting cycles.

[0026] Further, in the fine adjusting mode, the constant water level PID adjusting and the pressure PID adjusting are sequentially repeated, and the constant water level PID adjusting and the pressure PID adjusting comprise:

[0027] When the pressure change is less than the setting range, only the constant water level PID adjusting is repeated.

[0028] Further, the method further comprises:

[0029] Shutdown phase: in the case of shutdown of the ground grouting station inputting slurry into the buffer tank, the PLC control box controls the frequency converter to reduce the output frequency as the liquid level decreases and until it is maintained at the set pre-shutdown frequency, in the case of flow reduction to 0, the outlet control valve and the pressurized output device are closed.

[0030] The application further discloses a coal mine grouting dynamic adjustment device, which is used for realizing the adjustment method and comprises a buffer tank, an outlet pipeline, a PLC control box and a frequency converter.

[0031] The PLC control box is electrically connected with the frequency converter, the outlet control valve, the liquid level sensor, the liquid level switch and the outlet flow pressure sensor.

[0032] Further, the bottom of the buffer tank is in a conical slope type, and the outlet of the buffer tank is arranged on the sidewall of the lowest part of the buffer tank to correspond to the lowest part of the bottom.

[0033] The liquid level switch is arranged at a position with a limit water level height from the bottom of the buffer tank.

[0034] The application has at least the following beneficial effects:

[0035] The application realizes intelligent pressurization and intelligent dynamic adjustment of the coal mine grouting fire prevention system by switching between the adjustment modes, continuously and circularly switching between the constant water level PID and the constant pressure adjustment, and fusing and supplementing the constant water level and the constant pressure control.

[0036] Other beneficial effects of the application will be described in detail in the specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description.

[0038] Figure 1 Fig. 1 is a structural principle diagram of the coal mine grouting dynamic adjustment device.

[0039] Figure 2 is the circuit connection principle diagram of the dynamic regulation in the coal mine grouting.

[0040] Figure 3 is the principle diagram of the dynamic regulation method in the coal mine grouting.

[0041] Among them, 1-PLC control box, 2-frequency converter, 3-outlet flow pressure sensor, 4-outlet pipeline, 5-outlet control valve, 6-liquid level switch, 7-liquid level sensor, 8-buffer tank, 9-slurry pump, 10-variable frequency motor. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0043] The present application discloses a kind of coal mine grouting dynamic regulation method and device, for easy to describe and understand, first the structure of device is explained as follows.

[0044] Embodiment one

[0045] As shown in Figure 1 And Figure 2 The coal mine grouting dynamic regulation device mainly comprises PLC control box 1, frequency converter 2, outlet flow pressure sensor 3, outlet pipeline 4, outlet control valve 5, liquid level switch 6, liquid level sensor 7, buffer tank 8, slurry pump 9 and variable frequency motor 10. Among them, PLC control box 1 is electrically connected with frequency converter, outlet control valve, liquid level sensor, liquid level switch and outlet flow pressure sensor, and PLC control box 1 is used for intelligent control program storage and operation, which is the core equipment of the device intelligentization. Frequency converter 2 is used to control variable frequency motor 10, and the motor is controlled to run at a speed according to the signal given by PLC control box 1, and frequency converter 2 is also electrically connected with variable frequency motor 10, to control the output power of slurry pump 9. Outlet flow pressure sensor 3 is used to monitor the flow and pressure data value output by slurry pump 9. Outlet pipeline 4 is used to connect the rear conveying pipeline. Outlet control valve 5 is used to assist in adjusting the outlet pressure and flow of slurry pump 9. Liquid level switch 6 is a high liquid level limit switch of buffer tank 8. Liquid level sensor 7 is used to monitor the liquid level of buffer tank 8 in real time, preferably, the detection head of liquid level sensor 7 is about 0.15 meters away from the bottom of buffer tank 8. Buffer tank 8 is used to store upstream liquid, and slurry pump 9 is used to output the upstream liquid after secondary pressurization. Variable frequency motor 10 is used to drive slurry pump 9.

[0046] Among them, buffer tank 8, etc. Figure 1 As shown, the inlet is higher than the outlet, and the tank outlet is parallel to and connected to the suction inlet of the slurry pump 9. The electromechanical integrated structure composed of the buffer tank 8, the level switch 6, and the level sensor 7 is also one of the features of this invention. The bottom of the mud and slurry tank is designed with a conical slope structure. The liquid mixed with mud flowing in from the inlet flows down the slope to the outlet, so that the sedimented mud at the bottom flows into the suction inlet of the slurry pump 9 along with the upper slurry. When the slurry is buffered in the tank, the level sensor 7 detects the water level in the tank through a sensor probe vertically set in the tank and transmits the height data to the PLC control box 1 as an RS485 digital signal. When the slurry inflow speed exceeds the maximum adjustment speed set by the PLC control box 1, the liquid level will rise rapidly. When the liquid level rises to the limit, the level switch 6 is triggered. The level switch 6 transmits the upper limit switch signal to the PLC control box 1 to trigger the high-speed adjustment mode of the PLC control box 1.

[0047] The principle of the dynamic adjustment device for coal mine grouting relay disclosed in this embodiment is as follows: After grouting for fire prevention and extinguishing, the grout for fire prevention and extinguishing flows into the buffer tank 8 through the pipeline. The level sensor 7 detects the real-time level value and sends it to the PLC control box 1. The PLC control box 1 controls the frequency converter 2 to start operation after reaching the start-up level according to the program settings. The frequency converter 2 supplies power to the frequency converter motor 10 at the power frequency set by the PLC control box 1. The frequency converter motor 10 is responsible for providing power to the slurry pump 9. The slurry pump 9 draws slurry from the buffer tank 8, pressurizes it, and outputs it to the outlet pipeline 4, which then delivers it to the main pipeline of the coal mine grouting fire prevention and extinguishing system. The level switch 6 is responsible for detecting whether the level exceeds the maximum limit during operation and sending the action signal to the PLC control box 1. During the operation of the device, the PLC control box 1 continuously controls the output frequency of the frequency converter 2 in real time and controls the opening of the outlet control valve 5. The PLC control box 1 collects data from the outlet flow pressure sensor 3, the level switch 6, and the level sensor 7 in real time. When the liquid level drops continuously, the PLC control box 1 controls the variable frequency motor 10 to run at the lowest frequency until the output flow becomes zero, at which point the outlet control valve 5 is closed and the output of the variable frequency drive 2 is stopped.

[0048] Example 2

[0049] This embodiment discloses a method for dynamic adjustment during coal mine grouting relay, such as... Figure 3The method is suitable for various grouting fire prevention and extinguishing systems used in coal mines. The control nodes mainly include a PLC control box, a frequency converter, an outlet flow pressure sensor, an outlet control valve, a liquid level switch, and a liquid level sensor. The frequency converter is connected with a pressurizing output device for pressurizing the slurry and outputting to the outlet pipeline. The pressurizing output device includes a variable frequency motor electrically connected with the frequency converter and a slurry pump connected with the variable frequency motor. The working process of the present application starts from the ground grouting station. After the ground grouting station is operated, the slurry flows into the buffer tank through the pipeline. The liquid level sensor continuously detects the liquid level value and sends it to the PLC control box. When the PLC control box detects that the liquid level continues to rise and reaches the set working liquid level height according to the program setting, it controls the frequency converter to operate. The frequency converter enters the operating state to power on the variable frequency motor. The variable frequency motor drives the slurry pump to operate. The slurry is sucked out of the buffer tank by the slurry pump and pressurized output. The outlet pipeline is provided with an outlet flow pressure sensor for monitoring the flow and pressure of the output slurry. The flow and pressure data are uploaded to the PLC control box. Preferably, in the automatic control program of the PLC control box, a working liquid level height is set according to the maximum distance of the buffer tank, for example, the internal height of the buffer tank is designed to be about 1.35 meters according to the height of the coal mine site roadway. The working liquid level interval is set between 0.9 meters and 1.1 meters. The limit water level height of the liquid level switch 6 is set to 1.2 meters, and a 0.15 meter protection height is reserved.

[0050] Start-up process: When the PLC control box receives the liquid level continuous rising signal of the liquid level sensor, the opening degree of the outlet control valve is controlled to about 75%. When the liquid level continues to rise to the working liquid level height, the PLC control box sends the running command to the frequency converter according to the program initial setting. The variable frequency motor is powered on and drives the slurry pump to operate. The slurry is pressurized and output by the slurry pump. At this time, the frequency value of the frequency converter output is about 40 Hz, and the output speed is about 1000 r / min. The PLC control box reads the monitoring data of the outlet flow pressure sensor and automatically judges whether the output pressure meets the set value range. It is judged whether the current flow causes the liquid level of the buffer tank to rise or fall.

[0051] Coarse adjustment mode: after the device enters the running state, the PLC control box will determine whether the current liquid level is within the stable range, and whether the liquid level is rising or falling. If it is rising outside the stable range, the PLC control box controls the frequency converter output frequency to increase, at this time the speed-up rate is about 0.8 Hz / s, the pump station enters the acceleration state, the flow of the slurry pump is increased, and the water level of the buffer tank is reduced. When the water level drops to the upper limit of the stable range, it enters the fine adjustment state. At this time, due to the inertia of the speed regulation, the water level is in a slow decline; if it is falling outside the stable range, the PLC control box controls the frequency converter output frequency to decrease, and the falling rate is the same as the rising rate. The pump station enters the deceleration state, the flow of the slurry pump is reduced, and the water level of the buffer tank rises. When the water level rises to the lower limit of the stable range, it enters the fine adjustment mode. At this time, due to the inertia of the speed regulation, the water level is still in a slow rise.

[0052] When the inflow flow increases rapidly and the liquid level rises too fast to reach the limit water level height, the liquid level switch will be triggered. At this time, the PLC control box enters the large rate adjustment mode. The frequency regulation of the frequency converter will be forced to increase to 1.5 Hz / s, making the coarse adjustment slope larger and the acceleration and deceleration of the slurry pump faster, preventing the slurry from overflowing the buffer tank. When the liquid level drops to the limited area, it returns to the previous adjustment mode according to the current operating frequency.

[0053] Fine adjustment mode: when the liquid level reaches the stable range after coarse adjustment, the liquid level slowly rises or falls within the set value range. At this time, it enters the double adjustment state, i.e. constant water level adjustment and constant pressure adjustment. First, constant water level PID adjustment is performed to keep the liquid level within the set value range. The set value range can be the stable range of the liquid level. Specifically, the water level control value is the set value, the frequency converter output frequency is the adjustment value, and the measurement value of the liquid level sensor is the feedback value. Constant water level PID adjustment is suspended for about 12 seconds, and then pressure PID adjustment is performed.

[0054] Pressure PID adjustment is a double adjustment of valve opening and speed. The measurement value of the outlet flow pressure sensor is the feedback value. First, the valve opening is coarsely adjusted to approach the set value, and then only the frequency converter output frequency is used as the adjustment value for adjustment. The frequency control pressure adjustment is associated with the constant water level flow adjustment to facilitate water level adjustment after pressure adjustment. After about 9 seconds of pressure PID adjustment, it returns to the constant water level PID adjustment mentioned above, and enters a cyclic control state. In this cyclic control, if there is no significant change in pressure, the pressure PID adjustment is only adjusted once in the initial cycle, and only the water level PID adjustment is performed in the later cycle. Only when the pressure changes significantly, the pressure PID adjustment is involved in the control to form a water level and pressure double-cycle adjustment.

[0055] When the water level rising rate or the water level falling rate suddenly becomes large, causing the liquid level to exceed the liquid level stable range, the micro-adjustment mode cycle is exited, the water level and the pressure are re-adjusted, and then the micro-adjustment mode cycle control is entered again. Thus, the stable working state is entered repeatedly.

[0056] In the embodiments of the present application, various types of pre-set values such as the initial opening degree of the outlet control valve, the initial output frequency of the frequency converter, the frequency increasing / decreasing rate, and the pressure set value can be initially set by the person skilled in the art according to the requirements and the pipe diameter size, the pipe length, the vertical height, and the rated flow in the pipe of the grouting fire prevention and extinguishing system, and the specific process is not described herein.

[0057] Embodiment three

[0058] The present embodiment further illustrates the micro-adjustment mode disclosed in embodiment two, and the specific process of the mode is as follows:

[0059] First, the constant water level PID adjustment is needed, and the water level value is set to 1 m and the deviation is 15 cm. If the water level is in a slow rising state, the PLC control box gives the running frequency value of the frequency converter a change rate of about 0.2 Hz / s for rising control, the frequency converter slightly increases the rotating speed of the motor, the output flow of the slurry pump slightly increases to continue to reduce the liquid level, and the adjustment is repeated for three cycles to keep the liquid level in the set value range. If the water level is in a slow falling state, the PLC control box gives the running frequency value of the frequency converter a change rate of about 0.2 Hz / s for falling control, the frequency converter slightly reduces the rotating speed of the motor, the output flow of the slurry pump slightly reduces, and the adjustment is repeated for three cycles to keep the liquid level in the set value range.

[0060] Then, the constant pressure PID adjustment is entered. In the case that the current pressure is too high and exceeds the pressure limit value, the PLC control box controls the outlet control valve to increase the opening degree, at this time, the total pipe loss decreases, which causes the flow to increase and the pressure to decrease, and when the pressure decreases by 0.1 Mpa from the limit value, the valve is stopped to reserve the space for the next adjustment. Then, the PLC control box gives the running frequency value of the frequency converter a downward adjustment, the rotating speed of the motor of the slurry pump is reduced, the flow is reduced to return to the limit value range before the opening degree of the outlet control valve is increased, and the pressure continues to decrease until the pressure set value range, and the output slurry pressure is basically stabilized in the limit pressure value after three adjustment cycles. At this time, the PID water level adjustment is re-entered, and the stable operation state of the micro-adjustment of the frequency converter frequency is re-entered, that is, the output frequency of the frequency converter is slightly increased / decreased with the liquid level rising / falling.

[0061] When the pressure is lower than the pressure limit value, the PLC control box controls the outlet control valve to reduce the opening degree, which causes the flow to decrease and the pressure to rise to the limit pressure minus 0.1 Mpa, and then the PLC control box adjusts the frequency value of the frequency converter to increase the flow to return to the limit value range and increase the pressure to the limit pressure range, at this time, the frequency converter is in a stable operation state of slight increase and decrease. When the water level or pressure changes greatly, the stable operation is exited, if the pressure and water level are still in the fine adjustment range, the fine adjustment mode is re-entered and the stable operation is continued, if the pressure and water level change greatly and exceed the fine adjustment range, the coarse adjustment state is re-entered first, and then the stable operation state is gradually returned.

[0062] Finally, when the ground grouting station stops, the inflow flow decreases and the water level continues to decrease, the PLC control box controls the frequency converter to reduce the output frequency as the water level decreases, and when the water level still decreases when the frequency converter maintains at 28Hz output, it is determined that the ground station stops working, the outlet control valve is closed and stopped when the outlet flow decreases to 0, and then the standby state is entered to wait for the next operation.

[0063] It is worth mentioning that the limit value, set value and the like mentioned in the present application can represent a single numerical value or a range value based on its actual application.

[0064] During the dynamic adjustment process, the water level is kept from changing greatly, which is constant water level adjustment in industrial automation, and the pressure adjustment process after the water level changes is constant pressure adjustment. It is found in the field practice process that using any single adjustment method will produce factors affecting stable operation, only by correlating and implementing the water level and pressure adjustment together, and by mutual integration and nesting to form a cyclic complementary state, risks can be avoided, stable operation effect can be achieved, and stable dynamic adjustment of the coal mine fire prevention and extinguishing grouting system can be realized.

[0065] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for dynamic adjustment of grouting relay in coal mines, characterized in that, include: Start-up phase: Control the outlet control valve to open the outlet pipeline, and control the pressurization output device connected to the frequency converter to open, so that the slurry in the buffer tank is pressurized and output to the outlet pipeline; Adjustment Phase: In this phase, the adjustment mode is changed according to the current liquid level in the buffer tank. Specifically, if the slurry in the buffer tank is detected to be outside the set stable liquid level range, the coarse adjustment mode is used to adjust the pressurization output device until the liquid level is within the stable liquid level range, and then the fine adjustment mode is entered; if the liquid level is within the stable range, the fine adjustment mode is used to adjust the outlet control valve and the pressurization output device until the liquid level is outside the stable liquid level range, and then the coarse adjustment mode is entered. The coarse adjustment mode includes: when the liquid level is detected to exceed the upper or lower limit of the liquid level stability range, the output frequency of the frequency converter is increased or decreased to approach the liquid level stability range. The aforementioned fine-tuning modes include: Constant water level PID regulation: The frequency converter is controlled by PID regulation to adjust the liquid level in the buffer tank and keep the liquid level within the set range. The aforementioned constant water level PID control specifically includes: The water level control value is set, the output frequency of the frequency converter is adjusted, and the measurement value of the liquid level sensor in the buffer tank is fed back. The PID method is used to regulate three cycles to control the liquid level within a stable range. Pressure PID regulation: Adjusting the opening of the outlet control valve to make the pressure in the outlet pipeline close to the pressure set value; Since the flow rate in the outlet pipeline changes due to the adjustment of the outlet control valve opening, the frequency converter is controlled by PID regulation to adjust the flow rate in the outlet pipeline to bring the flow rate within the flow limit value. The pressure PID regulation specifically includes: When the pressure in the outlet pipeline is higher than the set pressure value, the PLC control box controls the outlet control valve to increase its opening until the pressure drops to within the adjustment range of the set pressure value, at which point the outlet control valve stops. The PLC control box then adjusts the operating frequency of the frequency converter to decrease, causing the flow rate to drop back to the flow limit value before the outlet control valve increased its opening, and the pressure continues to decrease to within the set pressure value. This process is repeated for three adjustment cycles until the pressure stabilizes at the set pressure value. When the pressure in the outlet pipeline is lower than the set pressure value, the PLC control box controls the outlet control valve to reduce its opening until the pressure rises to a level that is within the adjustment range of the set pressure value, at which point the outlet control valve stops. The PLC control box then adjusts the operating frequency of the frequency converter upwards, causing the flow rate to increase back to the flow limit value before the outlet control valve reduced its opening, and causing the pressure to continue to increase to the set pressure value. This process is repeated for three adjustment cycles until the pressure stabilizes at the set pressure value. The constant water level PID regulation and the pressure PID regulation are repeated sequentially.

2. The dynamic adjustment method for coal mine grouting relay according to claim 1, characterized in that, The startup phase includes: If a continuous rise in the liquid level inside the buffer tank is detected, adjust the outlet control valve to its initial opening. When the liquid level in the buffer tank is detected to rise to the set working liquid level, the frequency converter is controlled to make the slurry pump pressurize and output the slurry.

3. The dynamic adjustment method for coal mine grouting relay according to claim 1, characterized in that, In the aforementioned adjustment phase, the coarse adjustment mode specifically includes: When the liquid level exceeds the stable range and rises, the PLC control box controls the inverter to increase the output frequency, thereby increasing the flow rate in the outlet pipeline to lower the liquid level; when the liquid level drops to the upper limit of the stable range, it enters the micro-adjustment mode. When the liquid level exceeds the stable range and drops, the PLC control box controls the inverter to reduce the output frequency, thereby reducing the flow rate in the outlet pipeline to raise the liquid level; when the liquid level rises to the lower limit of the stable range, it enters the micro-adjustment mode.

4. The method for dynamic adjustment of coal mine grouting relay according to claim 1, characterized in that, In the aforementioned adjustment phase, the method of changing the adjustment mode according to the current liquid level in the buffer tank specifically includes: when the slurry in the buffer tank triggers the liquid level switch to reach the limit water level, it enters the high-rate adjustment mode; and when the liquid level drops to a limited area, it enters the coarse adjustment mode or the fine adjustment mode. The high-speed adjustment mode includes adjusting and increasing the inverter output frequency to the high-speed set value.

5. The method for dynamic adjustment of coal mine grouting relay according to claim 1, characterized in that, In the aforementioned fine-tuning mode, the sequential repetition of the constant water level PID regulation and pressure PID regulation includes: If the pressure change does not exceed the set range, repeat the constant water level PID regulation as described above.

6. The method for dynamic adjustment of coal mine grouting relay according to claim 1, characterized in that, The method also includes: Shutdown phase: When the ground grouting station that supplies grout to the buffer tank is shut down, the PLC control box controls the frequency converter to reduce the output frequency as the liquid level decreases until it is maintained at the set pre-shutdown frequency. When the flow rate drops to 0, the outlet control valve and the pressurization output device are closed.

7. A dynamic adjustment device for grouting relay in coal mines, characterized in that, The device is used to implement the method as described in any one of claims 1 to 6. The device includes: a buffer tank, an outlet pipeline, a PLC control box, and a frequency converter. The buffer tank is equipped with a liquid level sensor and a liquid level switch. A slurry pump is provided at the outlet of the buffer tank. The slurry pump is connected to a frequency converter motor. The buffer tank is connected to the outlet pipeline through the slurry pump. The outlet pipeline is equipped with an adjustable outlet control valve and an outlet flow and pressure sensor in sequence. The PLC control box is electrically connected to the frequency converter, outlet control valve, level sensor, level switch, and outlet flow and pressure sensor. The frequency converter is also electrically connected to the frequency converter motor.

8. The dynamic adjustment device for coal mine grouting relay according to claim 7, characterized in that, The bottom of the buffer tank is conical, and the outlet of the buffer tank is located on the lowest side wall of the buffer tank to correspond to the lowest point of the tank bottom. The level switch is set at a position at the maximum water level height from the bottom of the buffer tank.

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