Coal mine underground hole sealing grouting parameter monitoring device, grouting system and regulation and control method

Abstract

The invention discloses a coal mine underground hole sealing grouting parameter monitoring device, a grouting system and a regulation and control method. The monitoring device comprises a main steel pipe, an electromagnetic flowmeter, a pressure transmitter, a temperature sensor, an electromagnetic pressure regulating valve and a grouting parameter monitoring host, the electromagnetic flowmeter is used for monitoring instantaneous grouting flow in real time, the pressure transmitter is used for monitoring grouting pressure, the temperature sensor is used for monitoring slurry temperature, the electromagnetic pressure regulating valve is used for dynamically adjusting the grouting pressure, and the grouting parameter monitoring host is used for monitoring grouting parameters. The grouting parameter monitoring host is used for receiving, reading and storing the grouting parameters transmitted by the electromagnetic flowmeter, the pressure transmitter and the temperature sensor, and the grouting parameter monitoring host is further used for controlling the opening degree of the electromagnetic pressure regulating valve according to the received grouting parameters. According to the monitoring device, recording, storage and reading of underground hole sealing and grouting parameters are facilitated, and data support and foundation are provided for subsequent data analysis and processing, grouting technological process improvement and drilling hole sealing and grouting effect improvement.

Description

Technical Field

[0001] This invention relates to the field of monitoring parameters for underground grouting processes in coal mines, and particularly to a monitoring device, grouting system, and control method for underground sealing and grouting parameters in coal mines. Background Technology

[0002] Grouting technology is a widely applicable, simple, flexible, and highly stable construction method. It involves injecting grout into boreholes and coal / rock strata using grouting equipment. Grouting media include water, cement grout, gel grout, and polyurethane grout. Currently, grouting for underground gas drainage boreholes in coal mines uses a one-time full-hole grouting method, typically employing single-hole or multi-hole continuous grouting operations. At present, the grouting parameters for gas drainage boreholes are not yet digitized. Monitoring the grouting pressure involves installing mechanical pressure gauges on the grouting pump or grouting pipe, while recording the borehole sealing grouting flow rate and volume relies on rough estimations, resulting in significant errors. Therefore, solving the problem of digitizing borehole grouting parameters is crucial at this stage. Summary of the Invention

[0003] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0004] Currently, in coal mine underground gas drainage drilling and grouting operations, single-hole or up to three-hole continuous grouting is generally employed. Monitoring of grouting pressure involves mechanical pressure gauges installed on the grouting pump or grouting pipe. Grouting volume is roughly estimated based on the size of the grouting tank, and grouting flow rate is roughly calculated as an average of the grouting volume and grouting time. There is no metering equipment to monitor instantaneous grouting flow rate parameters, and the recording of borehole sealing grouting parameters relies on manual labor, resulting in significant errors and preventing digitization. Related technologies and equipment utilize online monitoring to track grouting parameters. However, sensors and other hardware require power to function, which necessitates electrician operation and frequent power consumption underground, making the process complex, time-consuming, and labor-intensive.

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, embodiments of the present invention propose a monitoring device for underground sealing and grouting parameters in coal mines, which facilitates the recording, storage, and retrieval of underground sealing and grouting parameters, providing data support and a foundation for subsequent data analysis and processing, improving the grouting process, and enhancing the effect of borehole sealing and grouting.

[0007] An embodiment of the present invention also proposes a grouting system.

[0008] An embodiment of the present invention also proposes a control method.

[0009] The coal mine underground sealing and grouting parameter monitoring device of this invention includes:

[0010] The main steel pipe is adapted to be connected to the grouting pipe, and the main steel pipe has a diameter of 12-20mm.

[0011] An electromagnetic flow meter is installed around the outside of the main steel pipe, and the electromagnetic flow meter is used to monitor the instantaneous flow rate of grouting in real time.

[0012] A pressure transmitter is connected to the main steel pipe via a tee connector, and the pressure transmitter is used to monitor the grouting pressure.

[0013] A temperature sensor is installed on the surface of the main steel pipe and is used to monitor the temperature of the slurry.

[0014] An electromagnetic pressure regulating valve is connected in series with the main steel pipe and is used to dynamically adjust the grouting pressure.

[0015] The grouting parameter monitoring host is connected to the electromagnetic flowmeter, the pressure transmitter, the temperature sensor and the electromagnetic pressure regulating valve. The grouting parameter monitoring host is used to receive, read and store the grouting parameters transmitted by the electromagnetic flowmeter, the pressure transmitter and the temperature sensor. The grouting parameter monitoring host is also used to control the opening degree of the electromagnetic pressure regulating valve according to the received grouting parameters.

[0016] In some embodiments, the grouting parameter monitoring host calculates the grouting volume by multiplying the instantaneous flow rate measured by the electromagnetic flowmeter with the cross-sectional area of ​​the main steel pipe, and calculates the grouting density by the ratio of the grouting volume to the grout volume.

[0017] In some embodiments, a self-regulating pressure regulating valve and a mobile battery box are also included. The self-regulating pressure regulating valve is connected in series with the main steel pipe and is used to automatically adjust the grouting pressure according to the downstream pressure. The mobile battery box is embedded inside the grouting parameter monitoring host and is used to power various devices.

[0018] In some embodiments, the grouting parameter monitoring host communicates with external devices via wired or wireless means.

[0019] In some embodiments, the electromagnetic flowmeter has a test range of 0–300 L / h, and the pressure transmitter has a test range of 0–5 MPa.

[0020] The grouting system of this invention includes:

[0021] Grouting tank;

[0022] A reciprocating pneumatic pump is connected to the grouting tank via a pipeline. The reciprocating pneumatic pump has an air inlet pipe on its air inlet side and an air inlet ball valve on the air inlet pipe. The reciprocating pneumatic pump also has a grouting pipe on its liquid outlet side and a grouting ball valve on the grouting pipe.

[0023] The monitoring device is the coal mine underground sealing grouting parameter monitoring device described in the above embodiment, and the main steel pipe and the grouting pipe are detachably connected in series.

[0024] The control method of this invention includes:

[0025] A monitoring device for monitoring grouting parameters is installed on the grouting pipe. After the sealing material and water are mixed evenly according to the preset material-to-water ratio, the four-stage grouting operation is started by a pneumatic grouting pump.

[0026] The first stage is the slow grouting stage. The valve of the pneumatic grouting pump is opened, and the grouting pressure slowly rises to the preset value. When the actual grouting volume reaches 15% of the theoretical grouting volume or the grouting pressure exceeds 0.6MPa, the second stage begins.

[0027] The second stage is the burst valve bursting stage. The grouting pressure rises rapidly to the design pressure of the burst valve. After the burst valve opens, the grout flows into the middle section of the sealing device bag. When the grout flow rate decay value or the grouting pressure decay value meets the preset conditions, the third stage begins.

[0028] The third stage is the rapid grouting stage, where the grouting pressure is adjusted to 0.8–1.2 MPa. When the actual grouting volume reaches 100% of the theoretical grouting volume, the fourth stage begins.

[0029] The fourth stage is the end of the grouting stage. The grouting pressure is adjusted to 0.6-0.8 MPa, and grouting continues until 110% of the theoretical grouting volume is reached. The end of grouting is determined based on the pressure holding status, the grouting pressure decay value, or whether the actual grouting volume reaches 120% of the theoretical grouting volume.

[0030] In some embodiments, the preset grouting pressure for the first stage of slow grouting is 0.5 MPa.

[0031] In some embodiments, the design pressure of the burst valve in the second stage is 0.8 to 1.5 MPa, the slurry flow rate attenuation value is greater than 6 L / min, and the grouting pressure attenuation value is 0.7 MPa.

[0032] In some embodiments, the criteria for determining the end of the fourth stage of grouting are as follows:

[0033] After closing the grouting ball valve, observe whether the grouting pressure reading changes. If the grouting pressure remains unchanged for 10 seconds, the grouting is complete.

[0034] If the grouting pressure decreases, and the decrease in grouting pressure is less than 0.2 MPa, the grouting is terminated.

[0035] If the pressure holding state is not reached and the grouting pressure decay value does not reach 0.2MPa, grouting continues until 120% of the theoretical grouting volume is reached, and then grouting ends.

[0036] In summary, this invention can realize the display, storage, reading, control and transmission of grouting parameters such as grouting pressure, grouting flow rate, grouting volume, grout density, and grouting temperature.

[0037] This invention is lightweight, portable, stable, and highly flexible. It is powered by a built-in battery, resulting in low power consumption. It does not require underground power connection, and a single person can monitor the parameters of low-flow borehole grouting, which can greatly reduce the labor intensity of workers.

[0038] This invention digitizes grouting parameters, solving the problem that recording and reading borehole sealing grouting parameters relies on manual methods and has large errors. It provides data support and a foundation for borehole grouting control and grouting process optimization. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a coal mine underground sealing and grouting parameter monitoring device according to an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of the grouting system according to an embodiment of the present invention.

[0041] Figure 3 This is a process flow diagram of the control method according to an embodiment of the present invention.

[0042] Figure label:

[0043] 1-Main steel pipe, 2-Electromagnetic flowmeter, 3-Pressure transmitter, 4-Temperature sensor, 5-Electromagnetic pressure regulating valve, 6-Grouting parameter monitoring host, 7-Self-operated pressure regulating valve, 8-Tee connector,

[0044] 10- Grouting tank, 11- Reciprocating pneumatic pump, 12- Air inlet pipe, 121- Air inlet ball valve, 13- Grouting pipe, 131- Grouting ball valve, 14- Monitoring device. Detailed Implementation

[0045] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0046] The following describes, with reference to the accompanying drawings, a coal mine underground sealing and grouting parameter monitoring device according to an embodiment of the present invention.

[0047] like Figure 1 As shown, the coal mine underground sealing grouting parameter monitoring device of this embodiment includes a main steel pipe 1, an electromagnetic flowmeter 2, a pressure transmitter 3, a temperature sensor 4, an electromagnetic pressure regulating valve 5, and a grouting parameter monitoring host 6.

[0048] The main steel pipe 1, with a diameter of 12-20mm, serves as the main structure connecting to the grouting pipe 13. Both ends of the main steel pipe 1 are connected in series with the grouting pipe 13 via threads or quick couplings to ensure the sealing and disassembly of the fluid passage.

[0049] Electromagnetic flowmeter 2 is installed around the outside of the main steel pipe 1. Electromagnetic flowmeter 2 monitors the instantaneous flow rate during grouting in real time through electromagnetic induction. The testing range of electromagnetic flowmeter 2 is 0–300 L / h, with an accuracy requirement of 1%. Grouting is completed in 10–20 minutes using a reciprocating grouting method. The grouting flow rate fluctuates, and the accuracy of the test for these fluctuations is ±1%, which can meet the monitoring requirements for flow rate fluctuations during reciprocating grouting.

[0050] Pressure transmitter 3 is connected to the main steel pipe 1 via a three-way connector 8. Pressure transmitter 3 is used to monitor grouting pressure. The testing range of pressure transmitter 3 is 0–5 MPa, with an accuracy requirement of 2.5% (±0.0625 MPa). The grouting method is reciprocating grouting, and the grouting flow rate fluctuates. The accuracy of testing these fluctuations is ±1%. It can respond to grouting pressure fluctuations in real time and feed them back to the grouting parameter monitoring host 6 to prevent equipment damage due to excessive pressure.

[0051] Temperature sensor 4 is installed on the surface of the main steel pipe 1. It adopts a high temperature resistant and corrosion resistant probe. Temperature sensor 4 is used to monitor the temperature of grout. If the temperature exceeds the set range (such as above 40℃), the monitoring host can trigger an alarm and adjust the grouting parameters to prevent the grout performance from deteriorating.

[0052] The electromagnetic pressure regulating valve 5 is connected in series with the main steel pipe 1 and is controlled by the grouting parameter monitoring host 6. The grouting pressure is dynamically adjusted according to the set parameters to optimize the sealing grouting effect.

[0053] The grouting parameter monitoring host 6 is connected to the electromagnetic flowmeter 2, pressure transmitter 3, temperature sensor 4, and electromagnetic pressure regulating valve 5. The grouting parameter monitoring host 6 receives, reads, and stores the grouting parameters transmitted from the electromagnetic flowmeter 2, pressure transmitter 3, and temperature sensor 4 in real time. The grouting parameter monitoring host 6 displays the grouting pressure, flow rate, temperature, grouting volume, and density parameters in real time, storing the monitoring data in timestamp format in the host's internal memory (such as an SD card or solid-state drive), supporting subsequent export and analysis. Data can be transmitted to external terminal devices via wired interfaces (such as USB, RS485) or wireless modules (such as Wi-Fi, Bluetooth), supporting remote data monitoring and analysis.

[0054] The grouting parameter monitoring host 6 controls the opening of the electromagnetic pressure regulating valve 5 according to the received grouting parameters to adjust the grouting pressure, thereby changing the grouting flow rate and optimizing the sealing grouting effect.

[0055] The grouting parameter monitoring host 6 calculates the grouting volume by multiplying and summing the instantaneous flow rate measured by the electromagnetic flowmeter 2 with the cross-sectional area of ​​the main steel pipe 1. In other words, the electromagnetic flowmeter 2, through a surround installation, uses the principle of electromagnetic induction to measure the grout flow velocity, calculates the instantaneous flow rate by combining it with the cross-sectional area of ​​the main steel pipe 1 (diameter 12-20mm), and accumulates the results through the monitoring host to obtain the grouting volume. For example, if the flowmeter measures an instantaneous flow rate of 150L / h, and grouting continues for 10 minutes, the grouting volume is 25L.

[0056] The grouting parameter monitoring host 6 calculates the grouting density by the ratio of grouting volume to grout volume. The grout volume is indirectly obtained from the volume of the grouting tank 10 or the volume of the grouting pipe 13. For example, if the grouting volume is 25L and the grout volume is 30L, the density is 0.83g / cm³. 3 .

[0057] like Figure 1 As shown, the coal mine underground sealing grouting parameter monitoring device of this embodiment of the invention also includes a self-regulating pressure regulating valve 7, which is connected in series with the main steel pipe 1. The self-regulating pressure regulating valve 7 automatically adjusts the grouting pressure according to the pressure after the valve.

[0058] The self-regulating pressure valve 7 and the solenoid pressure valve 5 work together to ensure equipment safety. The self-regulating pressure valve 7, as a safety protection device, automatically reduces the downstream pressure when the grouting pressure exceeds a set threshold, preventing PVC pipe or sealing bag rupture. The solenoid pressure valve 5 dynamically adjusts its opening based on the grouting pressure value set by the monitoring host, ensuring stable grouting pressure while adapting to flow fluctuations in reciprocating grouting.

[0059] The coal mine underground sealing grouting parameter monitoring device of this embodiment also includes a mobile battery box (not shown in the figure). The mobile battery box is embedded inside the grouting parameter monitoring host 6, supporting quick replacement or charging to reduce downtime. The mobile battery box can use lead-acid batteries, lithium batteries, etc., with a voltage range of 12V to 24V and a capacity range of 10A to 30A, supporting at least 10 to 20 minutes of continuous grouting operation to meet the requirements of a single sealing grouting and powering various sensors and control modules.

[0060] Furthermore, sensors and monitoring hosts can use low-power components to reduce energy consumption and extend battery life.

[0061] The portable grouting parameter monitoring device for underground coal mines, as described in this invention, can achieve real-time monitoring of grouting process parameters such as grouting pressure, grouting flow rate, grouting volume, grout density, and temperature underground. The device can be dismantled after grouting is completed, ready for the next sealing grouting operation. Data can be transmitted via both wired and wireless methods.

[0062] The grouting system of the present invention will now be described in conjunction with the accompanying drawings.

[0063] like Figure 2 As shown, the grouting system of this embodiment includes a grouting tank 10, a reciprocating pneumatic pump 11, and a monitoring device 14.

[0064] A reciprocating pneumatic pump 11 is connected to the grouting tank 10 via a pipeline. The reciprocating pneumatic pump 11 has an air inlet pipe 12 on its air inlet side, which connects to the compressed air system. An air inlet ball valve 121 is installed on the air inlet pipe 12 to control the air supply. The reciprocating pneumatic pump 11 has a grouting pipe 13 on its liquid outlet side, and a grouting ball valve 131 is installed on the grouting pipe 13 to regulate the grout flow rate.

[0065] The monitoring device 14 is a coal mine underground sealing grouting parameter monitoring device in any of the above embodiments, and the main steel pipe 1 and the grouting pipe 13 are detachably connected in series.

[0066] During the determination of grouting process parameters, the main steel pipe 1 is directly connected to the grouting pipe 13. The connection between the main steel pipe 1 and the grouting pipe 13 is either threaded or quick-connected, ensuring the sealing and disassembly of the fluid passage. The adjustment of grouting parameters is controlled by the grouting parameter monitoring host 6. After setting the process parameters, grouting can begin. The pneumatic pump is started, and the air supply is controlled by the air inlet valve 121. The grouting parameter monitoring host 6 displays the grouting parameters in real time, and the opening of the electromagnetic pressure regulating valve 5 is adjusted as needed. After grouting is completed, the monitoring device 14 is removed, and the data is transmitted to the ground system via a wireless module.

[0067] The control method of the present invention is described below with reference to the accompanying drawings.

[0068] The control method of this invention, based on the parameters measured by the borehole grouting parameter monitoring device 14, divides the grouting process into four stages. The electromagnetic pressure regulating valve 5 of the grouting system is adjusted according to the measured grouting parameters to control the entire grouting construction process in stages. The borehole grouting parameters include grouting pressure, grouting flow rate, theoretical grouting volume, and actual grouting volume.

[0069] First, connect the air inlet pipe 12 and the liquid inlet pipe to the corresponding interfaces of the mining reciprocating pneumatic pump 11. Add the sealing material and water to the grouting tank 10 according to the designed material-water ratio, and then start stirring. After stirring evenly, start the four-stage grouting operation.

[0070] like Figure 3 As shown, the four stages of the grouting process are as follows:

[0071] The first stage is the slow grouting stage. The valve of the pneumatic grouting pump is opened, and the grouting pressure slowly rises to 0.5 MPa. The grouting flow rate gradually increases and reaches equilibrium. The second stage of grouting begins when the actual grouting volume reaches 15% of the theoretical grouting volume, or when the grouting pressure exceeds 0.6 MPa. In other words, the criteria for entering the second stage of grouting are that the actual grouting volume reaches 15% of the theoretical grouting volume, or the grouting pressure exceeds 0.6 MPa. The actual grouting volume can be set according to the borehole diameter and the type of sealing hole.

[0072] The second stage is the burst valve bursting stage. As the bags at both ends of the sealing device inflate, the grouting pressure rises rapidly, the burst valve reaches a critical state, the grout flow rate in the grouting pipe 13 decreases, and the grouting pressure reaches the design pressure of the burst valve, which is between 0.8 and 1.5 MPa. The burst valve opens, and the grout flows into the middle section between the two bags. When the grout flow rate decreases by more than 6 L / min (grouting flow rate greater than 2 L / min and less than 8 L / min), or the grouting pressure decreases by 0.7 MPa, the third stage begins. The grout flow rate can be set according to the properties of the grouting material.

[0073] The third stage is the rapid grouting stage. As the grout enters the middle section of the plugs at both ends of the borehole sealer, the grouting pressure is adjusted to between 0.8 and 1.2 MPa by the main unit 6, which monitors the grouting parameters. When the actual grouting volume reaches 100% of the theoretical grouting volume, the fourth stage begins. The theoretical grouting volume is calculated based on the borehole diameter and the extraction pipe diameter.

[0074] The fourth stage is the grouting termination stage. When the actual grouting volume reaches 100% of the theoretical grouting volume, the grouting pressure is adjusted to between 0.6 and 0.8 MPa by the grouting parameter monitoring host 6, and grouting continues until 110% of the theoretical grouting volume is reached. The grouting is then terminated based on the pressure holding status, the grouting pressure decay value, or whether the actual grouting volume reaches 120% of the theoretical grouting volume.

[0075] The criteria for determining the end of the fourth stage of grouting are as follows:

[0076] After closing the grouting ball valve 131, observe whether the grouting pressure reading changes. If the grouting pressure remains unchanged for 10 seconds, it is in the sealing grouting and pressure-maintaining state, and the grouting is completed.

[0077] If the grouting pressure decreases, and the grouting pressure attenuation value is less than 0.2 MPa, the grouting is completed.

[0078] If the pressure holding state is not reached and the grouting pressure decay value does not reach 0.2MPa, grouting continues until 120% of the theoretical grouting volume is reached, and then grouting ends.

[0079] The control method of this invention guides workers in borehole sealing and grouting operations, improves the sealing effect of boreholes, enhances the digitalization level of borehole sealing and grouting management, and lays the foundation for the intelligent development of borehole sealing and grouting.

[0080] In summary, this invention can realize the display, storage, reading, control and transmission of grouting parameters such as grouting pressure, grouting flow rate, grouting volume, grout density, and grouting temperature.

[0081] This invention is lightweight, portable, stable, and highly flexible. It is powered by a built-in battery, resulting in low power consumption. It does not require underground power connection, and a single person can monitor the parameters of low-flow borehole grouting, which can greatly reduce the labor intensity of workers.

[0082] This invention digitizes grouting parameters, solving the problem that recording and reading borehole sealing grouting parameters relies on manual methods and has large errors. It provides data support and a foundation for borehole grouting control and grouting process optimization.

[0083] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0084] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0085] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0086] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0087] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0088] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A device for monitoring grouting parameters in underground coal mines, characterized in that, include: The main steel pipe is adapted to be connected to the grouting pipe, and the main steel pipe has a diameter of 12-20mm. An electromagnetic flow meter is installed around the outside of the main steel pipe, and the electromagnetic flow meter is used to monitor the instantaneous flow rate of grouting in real time. A pressure transmitter is connected to the main steel pipe via a tee connector, and the pressure transmitter is used to monitor the grouting pressure. A temperature sensor is installed on the surface of the main steel pipe and is used to monitor the temperature of the slurry. An electromagnetic pressure regulating valve is connected in series with the main steel pipe and is used to dynamically adjust the grouting pressure. The grouting parameter monitoring host is connected to the electromagnetic flowmeter, the pressure transmitter, the temperature sensor and the electromagnetic pressure regulating valve. The grouting parameter monitoring host is used to receive, read and store the grouting parameters transmitted by the electromagnetic flowmeter, the pressure transmitter and the temperature sensor. The grouting parameter monitoring host is also used to control the opening degree of the electromagnetic pressure regulating valve according to the received grouting parameters.

2. The coal mine underground sealing and grouting parameter monitoring device according to claim 1, characterized in that, The grouting parameter monitoring host calculates the grouting volume by multiplying the instantaneous flow rate measured by the electromagnetic flowmeter with the cross-sectional area of ​​the main steel pipe. The grouting parameter monitoring host calculates the grouting density by the ratio of the grouting volume to the grout volume.

3. The coal mine underground sealing and grouting parameter monitoring device according to claim 1, characterized in that, It also includes a self-regulating pressure regulating valve and a mobile battery box. The self-regulating pressure regulating valve is connected in series with the main steel pipe and is used to automatically adjust the grouting pressure according to the downstream pressure. The mobile battery box is embedded inside the grouting parameter monitoring host and is used to power various devices.

4. The coal mine underground sealing and grouting parameter monitoring device according to claim 1, characterized in that, The grouting parameter monitoring host communicates with external devices via wired or wireless means.

5. The coal mine underground sealing and grouting parameter monitoring device according to claim 1, characterized in that, The electromagnetic flowmeter has a test range of 0–300 L / h, and the pressure transmitter has a test range of 0–5 MPa.

6. A grouting system, characterized in that, include: Grouting tank; A reciprocating pneumatic pump is connected to the grouting tank via a pipeline. The reciprocating pneumatic pump has an air inlet pipe on its air inlet side and an air inlet ball valve on the air inlet pipe. The reciprocating pneumatic pump also has a grouting pipe on its liquid outlet side and a grouting ball valve on the grouting pipe. The monitoring device is a coal mine underground sealing grouting parameter monitoring device according to any one of claims 1-5, wherein the main steel pipe and the grouting pipe are detachably connected in series.

7. A control method, characterized in that, The control method is applicable to the grouting system according to claim 6, and the control method includes: A monitoring device for monitoring grouting parameters is installed on the grouting pipe. After the sealing material and water are mixed evenly according to the preset material-to-water ratio, the four-stage grouting operation is started by a pneumatic grouting pump. The first stage is the slow grouting stage. The valve of the pneumatic grouting pump is opened, and the grouting pressure slowly rises to the preset value. When the actual grouting volume reaches 15% of the theoretical grouting volume or the grouting pressure exceeds 0.6MPa, the second stage begins. The second stage is the burst valve bursting stage. The grouting pressure rises rapidly to the design pressure of the burst valve. After the burst valve opens, the grout flows into the middle section of the sealing device bag. When the grout flow rate decay value or the grouting pressure decay value meets the preset conditions, the third stage begins. The third stage is the rapid grouting stage, where the grouting pressure is adjusted to 0.8–1.2 MPa. When the actual grouting volume reaches 100% of the theoretical grouting volume, the fourth stage begins. The fourth stage is the end of the grouting stage. The grouting pressure is adjusted to 0.6-0.8 MPa, and grouting continues until 110% of the theoretical grouting volume is reached. The end of grouting is determined based on the pressure holding status, the grouting pressure decay value, or whether the actual grouting volume reaches 120% of the theoretical grouting volume.

8. The control method according to claim 7, characterized in that, The preset grouting pressure for the first stage of slow grouting is 0.5 MPa.

9. The control method according to claim 7, characterized in that, The design pressure of the burst valve in the second stage is 0.8 to 1.5 MPa, the slurry flow rate attenuation value is greater than 6 L / min, and the grouting pressure attenuation value is 0.7 MPa.

10. The control method according to claim 7, characterized in that, The criteria for determining the end of the fourth stage of grouting are as follows: After closing the grouting ball valve, observe whether the grouting pressure reading changes. If the grouting pressure remains unchanged for 10 seconds, the grouting is complete. If the grouting pressure decreases, and the decrease in grouting pressure is less than 0.2 MPa, the grouting is terminated. If the pressure holding state is not reached and the grouting pressure decay value does not reach 0.2MPa, grouting continues until 120% of the theoretical grouting volume is reached, and then grouting ends.

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