A coal mill and a coal mill operation monitoring system

Abstract

This application relates to the field of operation monitoring and maintenance technology for thermal power generation equipment, specifically disclosing a coal mill and a coal mill operation monitoring system. This system enables comprehensive, real-time, and accurate perception of the coal mill's operating status data and facilitates maintenance decisions. Specifically, it meets the coal mill's requirement for accurate and stable monitoring of the inlet and outlet pressure difference of its air-coal conveying and separation device, significantly improving the coal mill's reliability management level. The coal mill includes: a shell, a drive unit, a grinding device, an air-coal conveying and separation device, a lubrication and hydraulic device, and a sensor module. The sensor module includes a differential pressure sensor. The differential pressure sensor is installed with pressure taps on the inlet and outlet pipes of the air-coal conveying and separation device, respectively. Pressure taps are welded to the pressure taps, and two pressure tapping pipes are connected to the pressure taps on the inlet and outlet pipes, respectively. The other end of each pressure tapping pipe is connected to the same differential pressure transmitter.

Description

Technical Field

[0001] This application relates to the field of operation monitoring and maintenance technology of thermal power generation equipment, and specifically discloses a coal mill and a coal mill operation monitoring system. Background Technology

[0002] As a core piece of equipment in the pulverizing system of thermal power plants, the coal mill utilizes sensors to collect operational data. Based on this data, the coal mill operation monitoring system enables monitoring and maintenance management. The inlet and outlet pressure difference of the coal powder conveying and separation device in the coal mill is a key parameter reflecting the amount of coal powder filling inside the mill, ventilation efficiency, and separation effect, directly impacting equipment condition assessment and maintenance decisions. Currently, existing coal mills lack effective measurement capabilities for this pressure difference, making it difficult to meet the requirements for accurate and stable monitoring. Utility Model Content

[0003] This application discloses a coal mill and a coal mill operation monitoring system, which enables comprehensive, real-time, and accurate perception of the coal mill's operating status data, including meeting the coal mill's need for accurate and stable monitoring of the inlet and outlet pressure difference of its air-coal conveying and separation device.

[0004] A coal mill operation monitoring system includes a coal mill, a data acquisition and processing module, a DCS system module, a data storage module, a coal mill operation monitoring and maintenance module, and a display module, wherein: The sensor module signal output terminal of the coal mill is connected to the signal input terminal of the data acquisition and processing module. The signal output terminal of the data acquisition and processing module is connected to the signal input terminal of the DCS system module. The signal output terminal of the DCS system module is connected to the signal input terminal of the data storage module. The signal output terminal of the data storage module is connected to the signal input terminal of the coal mill operation monitoring and maintenance module. The signal output terminal of the coal mill operation monitoring and maintenance module is connected to the signal input terminal of the display module.

[0005] Furthermore, the data acquisition and processing module includes an edge smart gateway that adapts to multiple sensor protocols, and the signal output terminal of the sensor module is connected to the input terminal of the edge smart gateway.

[0006] Furthermore, the DCS system module integrates the coal mill operating data, coal mill control data, and process parameters output by the data acquisition and processing module and stores them in the data storage module.

[0007] A coal mill includes a shell, a drive unit, a grinding unit, an air-coal conveying and separating unit, a lubrication and hydraulic unit, and a sensor module. The sensor module includes a differential pressure sensor, and the differential pressure sensor is installed at the following location: Pressure tapping holes are provided on the air inlet pipe and air outlet pipe of the air-powder conveying and separating device. Pressure tapping nozzles are welded to the pressure tapping holes. Two pressure tapping pipes are connected to the pressure tapping nozzles of the air inlet pipe and air outlet pipe respectively. The other end of the pressure tapping pipes is connected to the same differential pressure transmitter.

[0008] Furthermore, the driving device includes a motor and a gearbox, the output shaft of the gearbox is connected to the main shaft of the grinding device, and the grinding device includes a grinding disc, a grinding roller and a shovel assembly disposed around the grinding disc.

[0009] Furthermore, the differential pressure transmitter is mounted on a support base on the outside of the coal mill housing, and the support base is fixed to the housing by threaded connection or welding.

[0010] Furthermore, the pressure tapping tube is made of high-temperature resistant metal flexible tube or seamless steel tube, and its two ends are connected to the pressure tapping nozzle and differential pressure transmitter respectively through threaded joints or quick-connect joints.

[0011] Furthermore, the pressure taps are symmetrically arranged on the outer walls of the inlet and outlet pipes along the central axis of the primary air flow direction, and the air-powder conveying and separating device includes a primary air pipe, a powder outlet pipe, and a separator structure.

[0012] Furthermore, the pressure tapping pipe is provided with a protective sleeve, which is fixed to the outer wall of the housing or the mounting frame, and a drain valve or condenser assembly is provided at the lowest point of the pressure tapping pipe.

[0013] Furthermore, the lubrication and hydraulic device includes a lubricating oil tank, a hydraulic cylinder, an oil pump, and a return oil pipeline. The lubricating oil temperature sensor is installed on the return oil pipeline, and the lubricating oil pressure sensor is installed on the main oil supply pipeline after the oil pump outlet.

[0014] Furthermore, the sensor module also includes a motor core temperature sensor, a motor bearing temperature sensor, a motor vibration sensor, and a gearbox bearing temperature sensor, wherein: the motor vibration sensor is installed at one location each in the vertical and horizontal directions on the bearing cover of the motor drive end; the motor bearing temperature sensor is installed in a threaded hole above the bearing housing; the motor core temperature sensor is installed in the stator winding slot; and the gearbox bearing temperature sensor is installed on the bearing housing of the input shaft.

[0015] Furthermore, a filter assembly is provided between the differential pressure transmitter and the pressure tapping pipe. The filter assembly includes a filter element and a detachable filter housing. The filter housing is connected to the pressure tapping pipe via threads or a flange.

[0016] Furthermore, the pressure tap is provided with a protective cover, which is fixed to the outer wall of the air duct by screws, and a ventilation gap is provided inside the protective cover.

[0017] One solution provided in this application discloses a coal mill and a coal mill operation monitoring system, enabling comprehensive, real-time, and accurate perception of the coal mill's operating status data and facilitating maintenance decisions, thereby significantly improving the reliability management level of the coal mill. The coal mill's sensor module includes a differential pressure sensor, which detects the pressure difference between the coal mill's inlet and outlet. Specifically, pressure taps are provided on the inlet and outlet pipes, with pressure taps welded to these taps. Two pressure taps are connected to the pressure taps on the inlet and outlet pipes, respectively, with the other end of each tap connected to the same differential pressure transmitter. This structural arrangement allows the differential pressure sensor to detect the real-time pressure difference between the coal mill's inlet and outlet airflow, forming basic monitoring parameters for the coal mill's ventilation and operating status. By connecting the dual pressure taps to a single differential pressure transmitter, accurate acquisition of the inlet and outlet airflow pressures can be achieved, ensuring the consistency and stability of the measurement signals and avoiding pressure tapping errors. Attached Figure Description

[0018] Figure 1 This is a diagram of an operation monitoring and maintenance system for a coal mill provided in one embodiment of this application; Figure 2 This is a side view schematic diagram of a coal mill provided in one embodiment of this application. Detailed Implementation To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] like Figure 1 The present application also provides a coal mill operation monitoring system, including a coal mill, a data acquisition and processing module, a DCS system module, a data storage module, a coal mill operation monitoring and maintenance module, and a display module.

[0020] The sensor module is a physical hardware sensor module used on the edge side of the thermal power plant to collect coal mill operating data. It includes a coal mill motor core temperature sensor, a coal mill motor bearing temperature sensor, a coal mill motor vibration sensor, a mill outlet temperature sensor, a mill inlet / outlet differential pressure sensor, a coal mill lubricating oil temperature sensor, a coal mill lubricating oil pressure sensor, and a coal mill gearbox bearing temperature sensor. The coal mill sensor module collects real-time coal mill operating status data through sensors installed in key parts of the coal mill. It uses an industrial Ethernet network to enable communication between the data acquisition and processing module, the DCS system module, the data storage module, the coal mill operation monitoring and maintenance module, and the display module. This allows for coal mill condition monitoring and maintenance decision-making, promoting a shift from planned maintenance to condition-based maintenance and significantly improving the reliability management level of the coal mill.

[0021] The data acquisition and processing module can be an edge computing gateway, an integrated intelligent terminal that combines multi-sensor access, protocol conversion, data processing, and transmission functions. For example, an edge intelligent gateway can be used to adapt to multiple sensor protocols and perform unified data preprocessing operations on the accessed data, including analog-to-digital conversion, filtering, anomaly denoising and interpolation, and feature extraction. Finally, the data is packaged into MQTT messages and output via industrial Ethernet at a frequency of 1 second. It is worth noting that, addressing the current inability to collect coal mill operating data, or issues such as latency and packet loss caused by long acquisition links in some solutions, an edge computing gateway-based data acquisition and transmission scheme is adopted. This scheme uses the edge computing gateway to achieve multi-sensor access adaptation, protocol conversion, data processing, and transmission, shortening the traditional coal mill data acquisition and transmission link.

[0022] The DCS (Distributed Control System) module is the system server on the field side of the thermal power plant for real-time data acquisition, monitoring, and command execution of various equipment. Through the DCS module, it receives coal mill data output from the data acquisition and processing module and integrates it with the coal mill control data and process parameters within the DCS system, providing a unified data foundation for coal mill operation status analysis, evaluation, and decision-making. It should be noted that by integrating various intelligent sensors with the DCS module, the data acquisition and processing chain is shortened, achieving comprehensive, real-time, and accurate perception of the coal mill's operating status and resolving the problem of unclear status.

[0023] Thermal power plant monitoring center: A data management, analysis, and visualization platform built using hyperconverged servers.

[0024] Data storage module: The big data management platform server aggregates multi-source heterogeneous data from the coal mills, including sensor data and operation and maintenance management data. For example, data warehouse technology can be used to store massive amounts of data from multiple coal mills, while providing open data interfaces to support data sharing and retrieval.

[0025] The coal mill operation monitoring and maintenance module includes three main processing sub-modules: equipment monitoring, status and risk assessment, and maintenance decision-making. It analyzes and processes coal mill operation data in real time, assesses and calculates its health and reliability, and makes maintenance strategies for high-risk failure modes to ensure the reliability of coal mill operation and reduce maintenance costs.

[0026] For example, the equipment monitoring submodule monitors the operating status of the coal mill by using threshold values ​​for various operating parameters and issues early warnings for parameters exceeding these thresholds. For example, the status and risk assessment submodule embeds a coal mill status assessment model and a fault risk measurement model. Utilizing the computing resources of the coal mill operation monitoring and maintenance module, it obtains operating data from the data storage module to drive model operation, assessing and calculating its health and reliability, and quantifying the risk level of each fault mode of the coal mill. For example, the maintenance decision-making submodule embeds a coal mill maintenance strategy library, which includes location, fault mode, fault cause, maintenance type, baseline cycle, maintenance time, and maintenance category. For example, the maintenance decision-making submodule, based on the coal mill maintenance strategy library and combined with the coal mill fault mode risk assessment, matches a corresponding monitoring strategy for each fault mode, providing a data foundation for maintenance personnel to execute.

[0027] To address issues such as inaccurate evaluation of coal mill operating status and imprecise maintenance, the coal mill operation monitoring and maintenance module can utilize artificial intelligence algorithms to mine and analyze the collected coal mill operating data, analyze and process the data in real time, assess and calculate its health and reliability, and determine maintenance strategies for high-risk failure modes.

[0028] Display module: Displays the coal mill's operating status, evaluation results, and maintenance strategies in real time on the client's monitor, guiding the execution of coal mill maintenance. For example, the display module is connected via a dedicated network cable and uses a 70-inch display screen to show the coal mill's operating status, evaluation results, and maintenance strategies, guiding the execution of coal mill maintenance. The data refresh rate can be once per second. In this embodiment, the coal mill's sensor module collects real-time operating data from various sensors and transmits the multi-sensor data to the data acquisition and processing module via industrial Ethernet. The data acquisition and processing module performs data parsing, protocol conversion, digital-to-analog conversion, and data preprocessing, and then connects the processed data to the edge DCS system server to achieve the fusion of coal mill operating status data, control data, and process parameters. This data is then transmitted to the data storage module via a dedicated industrial Ethernet line. The data storage module uses data warehouse technology to store the coal mill data. The coal mill operation monitoring and maintenance module retrieves data from the data storage module via an API interface and performs data mining analysis on the coal mill using an embedded artificial intelligence algorithm model. This allows for the assessment and calculation of the coal mill's health and reliability, and the determination of maintenance strategies for high-risk failure modes. The display module acquires the results data from the coal mill operation monitoring and maintenance module in real-time via network communication and displays the health status, risk level, maintenance strategies, and reliability statistical analysis through charts and other modes. This information guides the execution of coal mill maintenance, ensures the reliability of the coal mill's operation, and reduces maintenance costs.

[0029] It is worth noting that this embodiment, through the integration of multiple intelligent sensors and a DCS system, shortens the data acquisition and processing link, achieving comprehensive, real-time, and accurate perception of the coal mill's operating status and solving the problem of unclear status. Based on the coal mill's operating parameters, a status assessment and fault risk measurement model can be built using artificial intelligence algorithms, more accurately assessing equipment health and reliability. This provides precise and objective data support for maintenance decisions, enabling condition-based maintenance of the coal mill. This completely changes the passive, periodic maintenance model, allowing for the development of more accurate and detailed coal mill maintenance plans and improving the reliability of coal mill operation. Addressing the current planned maintenance method of periodic inspections and scheduled maintenance for coal mills in thermal power plants, which suffers from over-maintenance, under-maintenance, and high maintenance costs, this solution proposes a coal mill operation monitoring and maintenance system to achieve a shift from planned maintenance to condition-based maintenance, thereby improving the reliability of coal mill operation.

[0030] To facilitate understanding of the sensor module's installation location, the following diagram illustrates the structural composition, component functions, and spatial layout of a coal mill from side and top views. For example... Figure 2 (Side view of the coal mill) shows the vertical hierarchical structure of the coal mill from top to bottom, with the positions of each component marked.

[0031] Central coal drop pipe 101: The raw coal inlet at the top center, through which raw coal falls into the grinding disc.

[0032] Discharge valve air manifold 102 + discharge valve device 103: The discharge valve device 103 is used to control the discharge of qualified coal powder, and the air manifold provides power for it. The two work together to realize the conveying control of coal powder.

[0033] Coal mill outlet temperature and pressure measuring point 104: Installed on the discharge valve pipeline to monitor the outlet temperature and pressure parameters in real time, ensuring that the operating parameters are within a reasonable range.

[0034] Coal powder sampling platform 105: Operating platform used to extract coal powder samples, analyze indicators such as fineness and moisture, and judge the grinding effect.

[0035] Separator top cover 106: The top structure of the separator, connecting the central coal drop pipe 101, discharge valve device 103, etc., and is the upper boundary of the separator.

[0036] Spring loading device 107 + grinding roller device 108: The grinding roller device 108 is the core component for grinding raw coal (one set on each side). The spring loading device 107 provides grinding pressure to ensure the crushing effect on the coal.

[0037] Separator body device 109: The main body of the separator, used to separate qualified coal powder (after the primary air carries the coal powder upward, the coarse and fine separation is completed here).

[0038] Centerline of primary air inlet and inspection door: Primary air enters from this position, carrying coal dust upwards; the inspection door is used for internal maintenance operations.

[0039] Side body and its liner device 110: Side body, with internal liner to prevent wear and protect the body structure.

[0040] Drive unit 120: including components such as a gearbox and a motor, is a bottom drive component that drives the grinding disc to rotate and provides power for grinding.

[0041] Coal mill platform 121: This is an operating platform used for the operation and maintenance of components such as grinding rollers.

[0042] Combination Figure 2 As can be seen, the air inlet pipe is the access channel for primary air, and the inlet pressure tap of the mill inlet-outlet differential pressure sensor needs to be installed and directly connected to the primary air inlet of the coal mill. Figure 2 The primary air inlet is marked, and this inlet is the only channel for primary air to enter the coal mill. The pipe connected to it is the air inlet pipe. The air outlet pipe is the output channel for qualified pulverized coal. It needs to be equipped with the outlet pressure tap of the mill inlet-outlet differential pressure sensor and connected to the discharge valve device of the coal mill and the top cover of the separator (the pulverized coal is separated by the separator and then transported through the air outlet pipe). Figure 2 Mark the outlet temperature and pressure measuring points of the coal mill. The outlet temperature sensor is installed on the upper air outlet pipe of the coal mill, so the pipe where the measuring point is located is the air outlet pipe. At the same time, the pipe is connected to the discharge valve device at the top and to the separator device at the bottom (coal powder enters the air outlet pipe after being separated by the separator).

[0043] The overall structure and working process of the grinding mill: Raw coal enters through the central coal chute and falls onto the grinding disc driven by the drive device; the grinding roller device, under the pressure of the spring loading device, crushes and grinds the raw coal on the grinding disc. Primary air enters from the inlet, carrying the ground coal powder upwards, where coarse and fine separation is completed in the area formed by the separator body and the separator top cover; qualified coal powder is sent out through the discharge valve device, while unqualified coal powder falls back onto the grinding disc for further grinding.

[0044] Please continue reading for more details. Figure 2 As shown, the specific sensor installation locations are as follows: Figure 2 As shown, the dots indicate the corresponding sensor installation areas. It should be noted that these markings are only for understanding the approximate installation areas of each sensor module in the coal mill.

[0045] Motor vibration sensor 01: One sensor is installed on the bearing cover at the motor drive end, one in the vertical direction and one in the horizontal direction.

[0046] Motor bearing temperature sensor 02: It is installed above the bearing housing with a machined threaded hole and uses a screw-in installation method so that the probe tip can contact the outer ring of the bearing and directly measure the temperature of the hottest spot.

[0047] Motor core temperature sensor 03: installed in the pre-embedded stator winding slot.

[0048] Gearbox bearing temperature sensor 04: Installed on the bearing housing of the input shaft, it is screwed in through a machined mounting hole and points towards the outer ring of the bearing.

[0049] Lubricating oil pressure sensor (not shown in the diagram): Installed on the main oil supply line after the lubrication pump outlet of the lubrication and hydraulic system, connected via a three-valve manifold or direct thread. Lubricating oil temperature sensor (not shown in the diagram): Installed on the return line of the lubrication and hydraulic system.

[0050] Mill outlet temperature sensor 05: Installed on the primary air duct at the upper outlet of the coal mill.

[0051] Mill inlet and outlet differential pressure sensor 06: Holes are drilled and pressure taps are welded onto the primary air duct at the inlet and outlet of the coal mill, and the pressure is guided to the same differential pressure transmitter by two pressure taps.

[0052] The above-mentioned sensors are used to collect real-time operating data of the coal mill.

[0053] The above describes a coal mill operation monitoring system provided in the embodiments of this application. The following is a separate introduction to a coal mill provided in the embodiments of this application.

[0054] In one embodiment, a coal mill is provided, including a housing, an inlet pipe, an outlet pipe, and a sensor module. The sensor module includes a differential pressure sensor, which is used to detect the pressure difference between the inlet and outlet of the coal mill. Specifically, pressure tapping holes are respectively opened on the inlet pipe and the outlet pipe, and pressure tapping nozzles are welded to the pressure tapping holes; two pressure tapping pipes are respectively connected to the pressure tapping nozzles of the inlet pipe and the outlet pipe, and the other end of the pressure tapping pipes is connected to the same differential pressure transmitter.

[0055] In this embodiment, the core components of the coal mill include: a shell (the main structure housing the grinding-related parts), a drive unit (including a motor and a gearbox, providing power for the grinding action), a grinding device (including a grinding disc, grinding rollers, and a shovel assembly, used to crush and grind raw coal), an air-coal conveying and separating device (including an inlet pipe, an outlet pipe, and a separator; the inlet pipe is the primary air inlet channel, and the outlet pipe is the primary air outlet channel, responsible for conveying raw coal to the grinding area and separating qualified coal powder), and a lubrication and hydraulic device (including a lubricating oil tank, an oil pump, a main oil supply pipeline, and a return oil pipeline, etc., to ensure the lubrication of the rotating parts of the drive unit and the grinding device and the loading requirements of the grinding rollers). The above components are the constituent parts of the coal mill.

[0056] Differential pressure sensor in sensor module: refers to a complete set of components used to measure the pressure difference between the inlet and outlet of coal mill. The core component is differential pressure transmitter, and it is equipped with pressure taps, pressure pipes, etc. The pressure difference data measured can reflect the amount of coal powder filling and the primary air ventilation status inside the coal mill, and is a key parameter for evaluating the operating status of coal mill.

[0057] Pressure tapping hole / pressure tapping nozzle: The pressure tapping hole is a pressure collection hole opened on the air inlet pipe and air outlet pipe of the air-coal conveying and separation device; the pressure tapping nozzle is a metal pipe welded to the pressure tapping hole, and its function is to guide the pressure in the air pipe to the pressure tapping pipe to prevent the coal powder in the air pipe from directly entering the pressure tapping pipe and causing blockage.

[0058] Pressure tapping pipe: This is the pipe that connects the pressure tapping nozzle to the differential pressure transmitter. It is used to transmit the pressure signal in the duct. It needs to be adapted to the high temperature and dusty conditions during the operation of the coal mill to ensure stable pressure signal transmission.

[0059] In the specific assembly, pressure taps are symmetrically positioned along the central axis of the primary airflow on the outer walls of the inlet duct (selected in an area far from the coal mill shell and with stable airflow) and outlet duct (selected in an area near the separator outlet and with minimal airflow disturbance) of the air-coal conveying and separating device. This symmetrical arrangement avoids interference from local eddies on pressure measurement. The pressure taps must penetrate the duct wall thickness, and the inner wall of the duct must be free of burrs and residual coal dust. The metal pressure tap is aligned with the pressure tap and fixed using industrial-grade welding, ensuring the axis of the pressure tap is flush with the inner wall of the duct (to prevent the pressure tap from protruding and causing coal dust accumulation and blockage). The weld is free of defects such as porosity and slag inclusions, ensuring the airtightness of the pressure tapping channel. After welding, the inside of the pressure tap is purged with compressed air to remove welding slag and other impurities. Then, compressed air is introduced through a pressure testing fixture to check for leaks at the weld between the pressure tap and the duct, ensuring no pressure loss. Connect one end of the pressure tapping pipe to the pressure tapping nozzle through a sealing joint. Use sealing tape or gaskets to reinforce the seal at the interface to prevent pressure leakage. Connect the other ends of the two pressure tapping pipes (connected to the inlet and outlet air pipes respectively) to an easily accessible maintenance location on the outside of the coal mill casing. Connect them to the positive pressure port (corresponding to the inlet air pipe) and negative pressure port (corresponding to the outlet air pipe) of the same differential pressure transmitter respectively. Fix the pressure tapping pipes to the coal mill casing or a special mounting frame with pipe clamps to prevent the pressure tapping pipes from bending or shifting due to the vibration of the coal mill operation. At the same time, ensure that there are no dead corners for liquid accumulation in the pressure tapping pipes to prevent condensate from affecting the measurement.

[0060] In this structure, the power transmission chain is as follows: drive unit → grinding unit (main shaft). When the drive unit is running, it drives the grinding unit to rotate synchronously to complete the grinding of raw coal. The lubrication supply chain is as follows: lubrication and hydraulic unit → drive unit (motor / gearbox bearing) and grinding unit (grinding roller bearing). Lubricating oil and hydraulic oil are transported through pipelines. The air-coal flow chain is as follows: air inlet pipe (primary air + raw coal) → inside the shell (grinding area) → air outlet pipe (qualified air and coal), realizing the transportation of raw coal and the output of coal powder. The differential pressure monitoring chain is as follows: air inlet pipe pressure tap → pressure tap nozzle → pressure tapping pipe, air outlet pipe pressure tap → pressure tap nozzle → pressure tapping pipe. The two pressure tapping pipes are connected to the differential pressure transmitter to form a complete differential pressure measurement path.

[0061] In this embodiment, through this structural arrangement, the differential pressure sensor can realize real-time detection of the pressure difference between the inlet and outlet airflow of the coal mill, forming basic monitoring parameters for the ventilation and operation status of the coal mill. By connecting the dual pressure taps to a single differential pressure transmitter, accurate acquisition of the inlet and outlet airflow pressures can be achieved, ensuring the consistency and stability of the measurement signals and avoiding pressure tapping errors. Moreover, by flushing the pressure taps with the inner wall of the duct and symmetrically opening the pressure taps along the primary airflow direction, the measurement deviations caused by coal powder accumulation and local eddies in traditional pressure tapping methods can be effectively avoided. The standardized welding of the pressure taps and the connection process of the pressure tapping pipes simplify the on-site installation process. Subsequent maintenance only requires targeted cleaning of the pressure tap area, without disassembling the entire pipeline, reducing the complexity of operation and maintenance and labor costs.

[0062] In one embodiment, the driving device includes a motor and a gearbox, the output shaft of the gearbox is connected to the main shaft of the grinding device, and the grinding device includes a grinding disc, a grinding roller, and a shovel assembly disposed around the periphery of the grinding disc.

[0063] The drive unit of the coal mill consists of a motor and a gearbox. The output shaft of the gearbox is coaxially connected to the main shaft of the grinding device via a coupling (ensuring no offset in power transmission). The grinding device includes a grinding disc (horizontally arranged to support raw coal), grinding rollers (uniformly distributed along the circumference of the grinding disc, capable of rotating around their own axis, and applying grinding pressure via a hydraulic device), and a shovel assembly (fixed to the periphery of the grinding disc, rotating synchronously with the grinding disc, used to shovel up the raw coal and transport it to the grinding area between the grinding rollers and the grinding disc). In this structure, the power of the drive unit is reduced and amplified by the gearbox, then drives the grinding disc to rotate via the main shaft, thereby driving the shovel assembly and grinding rollers to work together to grind the raw coal. The combination of the motor and gearbox can precisely match the required speed and torque for grinding, avoiding low grinding efficiency due to insufficient power or energy waste due to excessive power.

[0064] In one embodiment, the differential pressure transmitter is mounted on a support base located on the outside of the coal mill housing. The support base is made of metal and can be rectangular or L-shaped. The support base is fixedly connected to the outer wall of the housing via threaded connections or welding, and has mounting holes for securing the differential pressure transmitter.

[0065] The core component of the differential pressure sensor, the differential pressure transmitter, is mounted on a support base on the outside of the coal mill housing. The support base is made of metal (compatible with the housing material to avoid structural deformation caused by thermal expansion and contraction differences). It is fixed to the housing by either threaded connection or welding: if threaded connection is used, the bottom of the support base has external threads, and the corresponding position of the housing has internal threads. It is fixed by screwing the threads together and adding an anti-loosening nut; if welding is used, the support base is fully welded to the outer wall of the housing, and the weld height is not less than 1 / 2 of the support base wall thickness to ensure connection strength.

[0066] In this embodiment, the structure ensures that the differential pressure transmitter is installed on an independent support, which can effectively avoid the impact of coal mill vibration on the transmitter, facilitate equipment maintenance and replacement, and improve structural safety and reliability.

[0067] In one embodiment, the pressure tapping tube is made of high-temperature resistant metal flexible tubing or seamless steel pipe. Both ends of the pressure tapping tube are connected to the pressure tap and the differential pressure transmitter respectively via threaded connectors or quick-connect fittings. Sealing gaskets are provided at all connections to prevent gas leakage. The pressure tapping tube connecting the pressure tap and the differential pressure transmitter uses high-temperature resistant metal flexible tubing or seamless steel pipe (suitable for the high-temperature environment of the ventilation duct during coal mill operation). The two ends of the pressure tapping tube are connected as follows: one end is screwed / plugged into the interface of the pressure tap via a threaded connector or quick-connect fitting, and the other end is connected to the positive and negative pressure interfaces of the differential pressure transmitter via the same type of connector. Sealing elements suitable for high-temperature operating conditions (such as fluororubber gaskets) are installed at all connectors to prevent pressure leakage.

[0068] In this embodiment, the metal hose of this structure has the characteristics of high temperature resistance, corrosion resistance and vibration resistance, and can adapt to the high temperature and dust conditions in the coal mill operating environment for a long time, maintaining the stability of the measuring pipeline.

[0069] In one embodiment, the pressure taps are symmetrically arranged along the central axis of the primary airflow direction and are respectively welded to the outer walls of the inlet pipe and the outlet pipe. The air-powder conveying and separating device includes a primary air pipe, a powder outlet pipe, and a separator structure.

[0070] The pressure taps are symmetrically arranged on the outer walls of the inlet and outlet pipes along the central axis of the primary air flow (i.e., the pressure taps are symmetrically positioned on the cross-section of the air pipe to ensure that the collected pressure is the average pressure inside the air pipe); the coal mill's air-coal conveying and separation device consists of a primary air pipe (conveying raw coal and primary air to the grinding area), a coal powder outlet pipe (conveying the separated qualified coal powder to the boiler), and a separator structure (installed upstream of the outlet pipe to separate unqualified coarse coal powder by centrifugal force). The pressure taps are located at the primary air inlet section of the inlet pipe and the downstream section of the separator in the outlet pipe.

[0071] In this embodiment, the pressure taps are located in areas with relatively stable airflow to reduce turbulence interference. This symmetrical arrangement ensures that the airflow state at the inlet and outlet pressure taps remains consistent, guaranteeing that the collected pressure data accurately reflects the overall pressure state within the duct and facilitating the acquisition of accurate differential pressure signals.

[0072] In one embodiment, a protective sleeve is fitted over the pressure-sensing pipe. The protective sleeve can be made of metal or high-temperature resistant engineering plastic and is fixed to the outer wall of the housing or the mounting frame by clamps or brackets, providing mechanical protection for the pressure-sensing pipe. The protective sleeve (made of metal, with higher strength than the pressure-sensing pipe, used for collision and vibration protection) is fixed to the outer wall of the coal mill housing or a dedicated mounting frame by pipe clamps (ensuring that the protective sleeve and the pressure-sensing pipe are fixed synchronously without relative displacement).

[0073] In this embodiment, the structure can prevent external impacts or high-temperature particles from damaging the pressure-sensing pipe, thereby improving the service life and mechanical strength of the overall pipeline system.

[0074] In one embodiment, a drain valve or condenser assembly is provided at the lowest point of the pressure tapping pipe. The condenser assembly may be a detachable structure, including a transparent pressure-resistant housing and a condensation chamber, connected to the pressure tapping pipe by threads or clamps. At the lowest point of the pressure tapping pipe (the lowest position along the pressure transmission direction), a drain valve or condenser assembly is provided: the drain valve is a manual or automatic valve used to drain condensate from the pressure tapping pipe; the condenser assembly cools the moisture to prevent condensate from entering the differential pressure transmitter.

[0075] In this embodiment, condensate or water in the pipeline can be automatically or periodically drained during operation to prevent liquid blockage or corrosion of the pipeline, keep the pipeline unobstructed, and avoid signal delay or measurement deviation.

[0076] In one embodiment, the lubrication and hydraulic device includes a lubricating oil tank, a hydraulic cylinder, an oil pump, and a return oil line. The lubricating oil temperature sensor is installed on the return oil line, and the lubricating oil pressure sensor is installed on the main oil supply line after the oil pump outlet.

[0077] In this embodiment, the temperature sensor is installed in the return oil pipeline, which can directly reflect the actual temperature of the lubricating oil after passing through the friction components (and better reflect the lubrication status of the components), avoiding the temperature lag problem caused by installing it in the oil tank; the pressure sensor is installed in the main oil supply pipeline, which can monitor the output pressure of the oil pump in real time, promptly detect oil pump failure or insufficient oil supply caused by pipeline blockage, and prevent damage to components such as grinding rollers and bearings due to poor lubrication; the coordinated monitoring of the two sensors realizes dual control of pressure and temperature, providing lubrication status data for the coal mill operation monitoring and maintenance module.

[0078] In one embodiment, the sensor module further includes: a motor core temperature sensor, a motor bearing temperature sensor, a motor vibration sensor, a lubricating oil pressure sensor, and a gearbox bearing temperature sensor. All of these sensors are connected to the monitoring system to form a comprehensive data acquisition unit for the coal mill's operating parameters.

[0079] In this embodiment, the sensor module configuration enables joint monitoring of multiple parameters of the coal mill, facilitating the judgment of operating trends and status analysis, and enabling comprehensive analysis of equipment status, thereby improving the comprehensiveness and systematization of monitoring.

[0080] In one embodiment, the sensors are installed in the following positions: a motor vibration sensor is installed at one location in the vertical direction and one location in the horizontal direction on the bearing cover of the motor drive end; a motor bearing temperature sensor is installed in a threaded hole machined above the bearing seat; a motor core temperature sensor is installed in the stator winding slot; and a gearbox bearing temperature sensor is installed on the bearing seat of the input shaft.

[0081] In this embodiment, the combination of multiple locations and types of sensors enables comprehensive monitoring of vibration and temperature of core drive components such as motors and gearboxes, covering key fault risk points of the drive system (such as bearing wear and core overheating). The sensor installation locations are all in the most sensitive areas of component temperature and vibration, ensuring that the collected data can accurately reflect the operating status of the components and avoid fault warning delays caused by improper installation locations.

[0082] In this embodiment, the reasonable arrangement of the sensors ensures accurate acquisition of the temperature and vibration status of each key component. This arrangement can accurately reflect the thermal and vibration status of each key component, providing a multi-point monitoring basis for the safe operation of the coal mill.

[0083] In one embodiment, a filter assembly is provided between the differential pressure transmitter and the pressure tapping tube. The filter assembly includes a filter element and a removable filter housing. The filter housing is connected to the pressure tapping tube via threads or a flange.

[0084] A filter assembly is connected in series between the differential pressure transmitter and the pressure tapping tube. This assembly includes a filter element (made of a high-temperature and corrosion-resistant porous metal, used to filter dust inside the pressure tapping tube) and a detachable filter housing (made of metal, which encloses the filter element). The two ends of the filter housing are connected to the interfaces of the pressure tapping tube and the differential pressure transmitter respectively through threads or flanges. When disassembling, the filter element can be removed simply by loosening the threads or removing the flange bolts.

[0085] In this embodiment, dust and fine particles in the air can be blocked from entering the transmitter, preventing sensor blockage or damage, thereby improving the reliability of the detection system.

[0086] In one embodiment, the pressure tap is provided with a protective cover. The protective cover is made of metal sheet and is fixed to the outer wall of the air duct with screws. The protective cover has ventilation gaps inside.

[0087] The pressure tapping nozzle is equipped with a protective cover (made of metal, in an arc or box shape, covering the pressure tapping nozzle and the surrounding welding area). The protective cover is fixed to the outer wall of the air duct with screws (the screws are evenly distributed around the perimeter of the protective cover to ensure a firm fixation). The side wall or top of the protective cover has ventilation gaps (the gap width is smaller than the diameter of the pressure tapping nozzle to prevent foreign objects from entering) to balance the air pressure inside and outside the protective cover and not affect the pressure tapping nozzle's ability to collect pressure inside the air duct.

[0088] In this embodiment, a ventilation gap is provided at the bottom of the protective cover, allowing the pressure tap to remain connected to the external airflow while being protected. This structure improves the protection capability of the pressure tap, preventing impact from external objects and dust accumulation, and facilitating later maintenance and repair.

[0089] It should be noted that the function of a coal mill is to crush, dry, and grind raw coal into fine pulverized coal that meets the combustion requirements of a boiler, ensuring efficient and stable combustion. It is the core equipment of the pulverizing system in a thermal power plant, and its operating status directly affects the boiler's combustion efficiency and the safe and economical operation of the power plant. Currently, thermal power plants generally use a traditional point-inspection and scheduled maintenance model for coal mill maintenance and management. This model mainly relies on manual periodic inspections and point checks, which lacks clarity regarding the actual operating status of the coal mill, results in unscientific maintenance and repair plans, and leads to under-maintenance and over-maintenance, resulting in high maintenance costs. This model can no longer meet the high reliability requirements of the new power market for coal-fired units.

[0090] In this application, "multiple" refers to two or more.

[0091] In this application, unless otherwise expressly defined, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0092] The terms “first,” “second,” “third,” “fourth,” etc., in this application (if present) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0093] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A coal mill, comprising a shell, a drive unit, a grinding unit, an air-coal conveying and separating unit, a lubrication and hydraulic unit, and a sensor module, characterized in that, The sensor module includes a differential pressure sensor, and the differential pressure sensor is installed at the following location: Pressure tapping holes are provided on the air inlet pipe and air outlet pipe of the air-powder conveying and separating device. Pressure tapping nozzles are welded to the pressure tapping holes. Two pressure tapping pipes are connected to the pressure tapping nozzles of the air inlet pipe and air outlet pipe respectively. The other end of the pressure tapping pipes is connected to the same differential pressure transmitter.

2. The coal mill according to claim 1, characterized in that, The driving device includes a motor and a gearbox. The output shaft of the gearbox is connected to the main shaft of the grinding device. The grinding device includes a grinding disc, a grinding roller, and a shovel assembly arranged around the grinding disc.

3. The coal mill according to claim 1, characterized in that, The differential pressure transmitter is mounted on a support base on the outside of the coal mill housing. The support base is fixed to the housing by threaded connection or welding. The pressure tapping pipe is made of high-temperature resistant metal hose or seamless steel pipe, and its two ends are connected to the pressure tapping nozzle and the differential pressure transmitter by threaded joints or quick-connect joints, respectively.

4. The coal mill according to claim 1, characterized in that, The pressure taps are symmetrically arranged on the outer walls of the inlet and outlet pipes along the central axis of the primary air flow. The air-powder conveying and separating device includes a primary air pipe, a powder outlet pipe, and a separator structure.

5. The coal mill according to claim 1, characterized in that, The pressure tapping pipe is equipped with a protective sleeve, which is fixed to the outer wall of the housing or the mounting frame, and a drain valve or condenser assembly is provided at the lowest point of the pressure tapping pipe.

6. The coal mill according to claim 1, characterized in that, The lubrication and hydraulic device includes a lubricating oil tank, a hydraulic cylinder, an oil pump, and a return oil pipeline. The lubricating oil temperature sensor is installed on the return oil pipeline, and the lubricating oil pressure sensor is installed on the main oil supply pipeline after the oil pump outlet. The sensor module also includes a motor core temperature sensor, a motor bearing temperature sensor, a motor vibration sensor, and a gearbox bearing temperature sensor. The motor vibration sensor is installed at one location each in the vertical and horizontal directions on the bearing cover of the motor drive end; the motor bearing temperature sensor is installed in the threaded hole above the bearing seat; the motor core temperature sensor is installed in the stator winding slot; and the gearbox bearing temperature sensor is installed on the bearing seat of the input shaft.

7. The coal mill according to claim 1, characterized in that, A filter assembly is provided between the differential pressure transmitter and the pressure tapping pipe. The filter assembly includes a filter element and a detachable filter housing. The filter housing is connected to the pressure tapping pipe by threads or flanges. A protective cover is provided outside the pressure tapping nozzle. The protective cover is fixed to the outer wall of the air duct by screws. A ventilation gap is provided inside the protective cover.

8. A coal mill operation monitoring system, characterized in that, Includes a coal mill, a data acquisition and processing module, a DCS system module, a data storage module, a coal mill operation monitoring and maintenance module, and a display module as described in any one of claims 1-7, wherein: The sensor module signal output terminal of the coal mill is connected to the signal input terminal of the data acquisition and processing module. The signal output terminal of the data acquisition and processing module is connected to the signal input terminal of the DCS system module. The signal output terminal of the DCS system module is connected to the signal input terminal of the data storage module. The signal output terminal of the data storage module is connected to the signal input terminal of the coal mill operation monitoring and maintenance module. The signal output terminal of the coal mill operation monitoring and maintenance module is connected to the signal input terminal of the display module.

9. The coal mill operation monitoring system according to claim 8, characterized in that, The data acquisition and processing module includes an edge smart gateway that adapts to multiple sensor protocols, and the signal output terminal of the sensor module is connected to the input terminal of the edge smart gateway.

10. The coal mill operation monitoring system according to claim 8, characterized in that, The DCS system module integrates the coal mill operation data, coal mill control data, and process parameters output by the data acquisition and processing module and stores them in the data storage module.

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