Centralized gas supply system of ball mill and pressure stabilization control method

Abstract

The invention discloses a ball mill centralized gas supply system and a pressure stabilization control method. The ball mill centralized gas supply system is composed of at least one ball mill unit, a gas source system unit, a main pipeline unit, a branch pipeline unit and a control system unit. The air source system unit supplies air to a pneumatic clutch and a gear lubricating device in the ball mill unit; the system comprises a first air compressor, a second air compressor and a third air compressor, the first air compressor is connected with a first air storage tank through a first air source pipeline, the first air source pipeline is connected with a first pressure transmitter and a first electric ball valve, and the second air compressor is connected with a second air storage tank through a second air source pipeline. A second air source pipeline is connected with a second pressure transmitter and a second electric ball valve, and a third air compressor is connected with a third pressure transmitter; and the PLC is connected with each electric control component in the gas source system unit and the branch pipeline unit through cables. Connecting pipelines are compactly arranged, the air supply efficiency is high, the energy-saving effect is remarkable, the pressure stabilizing effect is good, and efficient and stable operation of the ball mill can be guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of grinding and selecting air supply, in particular to a ball mill centralized air supply system and a voltage stabilization control method. Background Art

[0002] The ball mill is the most widely used grinding equipment. Its main function is to grind the crushed minerals to the particle size required for sorting operations. The pneumatic clutch and gear lubrication device are two important transmission components to ensure the normal operation of the ball mill. They mainly realize the functions of inflating and exhausting the pneumatic tires and lubricating the gears. What they have in common is that they require an air source with sufficient pressure and stable flow. The traditional ball mill air supply system often consists of an independent piston air pump and a small air storage tank. During use, there are problems such as unstable air pressure and airflow, high equipment failure rate, and lack of backup air source. The specific manifestations are:

[0003] (1) High energy consumption: The piston air pump runs continuously at full load at a fixed speed and cannot dynamically adjust the speed according to the load, resulting in serious waste of electricity;

[0004] (2) Large pressure fluctuations and poor pressure regulation performance: The inlet pressure of the ball mill is significantly affected by changes in working conditions and requires manual intervention and adjustment, resulting in poor stability;

[0005] (3) High equipment failure rate: The working performance of the air pump is unstable and there is no backup air source. Once a failure occurs and the air is stopped, it will seriously affect the normal operation of the ball mill and even cause the series of ball mills to stop, which has a great impact on the grinding and selection production;

[0006] (4) Poor system pressure stabilization system: When the system pressure cannot be guaranteed, there is no backup gas source available.

[0007] Chinese patent CN207086035U discloses a ball mill air supply system. On the basis of the original air pump, an air compressor is added as the main air source to supply air to the clutch. When the main air source pressure is insufficient, the backup air source (air pump) is started. The system has a simple configuration and can solve the problem of air source replenishment when the air pressure is lower than the minimum set value to a certain extent. However, there are still problems such as a single air supply object, low pressure stabilization efficiency, poor energy saving effect, and inability to achieve timely feedback of working signals. Summary of the Invention

[0008] The purpose of the present invention is to provide a ball mill centralized air supply system and pressure stabilization control method, which has compact connecting pipeline arrangement, high air supply efficiency, significant energy saving effect, and good pressure stabilization effect, and can ensure the efficient, stable and safe operation of the ball mill, so as to solve the problems raised in the above background technology.

[0009] To achieve the above object, the present invention provides the following technical solution: a ball mill centralized air supply system, comprising at least one ball mill unit, an air source system unit, a main pipeline unit, a branch pipeline unit and a control system unit;

[0010] The ball mill unit includes a ball mill drum, a synchronous motor, a pneumatic clutch and a gear lubricating device; the air source system unit includes a first air compressor and a second air compressor, the first air compressor provides an air source for the pneumatic clutch, and the pneumatic clutch is used to complete the connection or disconnection of the synchronous motor and the ball mill drum under stable air source power; the first air compressor is connected to the first air storage tank through a first air source pipeline, the first air source pipeline is connected to the first pressure transmitter and the first electric ball valve in sequence, and the first check valve is connected to the air inlet front end of the first air storage tank; the second air compressor provides an air source for the gear lubricating device, and the gear lubricating device is used to spray lubricating oil on the surface of the meshing gear, the second air compressor is connected to the second air storage tank through a second air source pipeline, the second air source pipeline is connected to the second pressure transmitter and the second electric ball valve in sequence, and the second check valve is connected to the air inlet front end of the second air storage tank; the air source system unit also includes a third air compressor, and the exhaust port of the third air compressor is connected to the third pressure transmitter;

[0011] The air source system unit is connected to the main pipeline unit and the branch pipeline unit, the exhaust port of the first air storage tank is connected to the first air supply main pipe, and the pneumatic clutch is connected to the first air supply main pipe through the first air supply branch pipe; the exhaust port of the second air storage tank is connected to the second air supply main pipe, and the gear lubrication device is connected to the second air supply main pipe through the second air supply branch pipe;

[0012] The control system unit includes a PLC controller and an audible and visual alarm. The PLC controller is connected to the various electronic control components in the gas source system unit and the branch pipeline unit through cables; the audible and visual alarm is connected to the signal output end of the PLC controller for audible and visual feedback alarm.

[0013] Furthermore, the pneumatic clutch requires an air source pressure of 0.7-1.0 MPa, and the gear lubrication device requires an air source pressure of 0.5-0.8 MPa.

[0014] Furthermore, the first air compressor is provided with a first air compressor controller, the loading pressure of the first air compressor controller is set to 0.7MPa, and the unloading pressure is set to 1.0MPa; the second air compressor is provided with a second air compressor controller, the loading pressure of the second air compressor controller is set to 0.5MPa, and the unloading pressure is set to 0.8MPa. The first air compressor and the second air compressor are main air compressors, and permanent magnet variable frequency screw air compressors are adopted; the third air compressor is provided with a third air compressor controller, the loading pressure of the third air compressor controller is set to 0.7MPa, and the unloading pressure is set to 1.0MPa. The third air compressor is an auxiliary air compressor, and an industrial frequency screw air compressor is adopted.

[0015] Furthermore, the third air compressor is connected in parallel with the first air compressor and the second air compressor. The third air compressor is connected to the first air source pipeline through a third air source pipeline, and is connected to the second air source pipeline through a fourth air source pipeline. The first electric V-shaped ball valve is connected to the third air source pipeline, and the second electric V-shaped ball valve is connected to the fourth air source pipeline.

[0016] Furthermore, the front end of the air inlet of the second air storage tank is connected to a pressure reducing valve, the rear end of the air outlet is connected to a pressure relief valve, and the pressure relief valve is connected in parallel to the second air supply main.

[0017] Furthermore, the first gas supply branch pipe is connected to a first electric stop valve and a fourth pressure transmitter, and the second gas supply branch pipe is connected to a second electric stop valve and a fifth pressure transmitter.

[0018] Furthermore, the electronic control components include a first air compressor controller, a first pressure transmitter, a first electric ball valve, a second air compressor controller, a second pressure transmitter, a second electric ball valve, a third air compressor controller, a third pressure transmitter, a first electric V-type ball valve, a second electric V-type ball valve, a first electric stop valve, a fourth pressure transmitter, a second electric stop valve, and a fifth pressure transmitter, wherein the electric V-type ball valve and the pressure transmitter use 4-20mA analog signals, and the rest use digital signals.

[0019] The present invention also provides another technical solution: a method for controlling the pressure stabilization of a ball mill centralized air supply system, comprising the following steps:

[0020] S1: Using a PLC controller to collect pressure data from the fourth and fifth pressure transmitters in real time, and respectively calculate the pressure drop rates ΔP / Δt of the first and second gas supply branch pipes;

[0021] S2: Based on the ΔP / Δt data, the first and second gas supply branch pipes are respectively subjected to pressure stabilization control. The method is as follows:

[0022] (1) When ΔP / Δt is less than 0.01 MPa / s, the first electric stop valve and the second electric stop valve are in the main control mode, and the first and second air compressors are auxiliary controlled by variable frequency speed regulation;

[0023] (2) When 0.01MPa / s≤ΔP / Δt<0.03MPa / s, the first and second air compressors are controlled by variable frequency speed regulation, and the first and second electric stop valves are controlled as auxiliary valves;

[0024] (3) When ΔP / Δt≥0.03MPa / s, or the pressure data of the fourth pressure transmitter is less than 0.7MPa and the pressure data of the fifth pressure transmitter is less than 0.5MPa, start the third air compressor, the first electric V-type ball valve, and the second electric V-type ball valve to compensate for the air supply;

[0025] (4) When the pressure data of the fourth pressure transmitter and the fifth pressure transmitter reach the maximum pressure setting value, turn off the third air compressor and close the first electric V-type ball valve and the second electric V-type ball valve.

[0026] Furthermore, when the pneumatic clutch needs auxiliary air supply to start the third air compressor, the pressure difference between the third pressure transmitter and the first pressure transmitter is compared in real time. When ΔP is less than 0.05MPa, the first electric V-type ball valve is opened; when the gear lubrication device needs auxiliary air supply to start the third air compressor, the difference between the third pressure transmitter and the second pressure transmitter is compared in real time. When ΔP is less than 0.05MPa, the second electric V-type ball valve is opened.

[0027] Furthermore, the first electric V-type ball valve and the second electric V-type ball valve adopt a two-stage opening method: the valve is opened to 20% opening in the first 1 second, and then linearly opened to 100% opening in the next 2 seconds.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. This ball mill centralized air supply system and pressure stabilization control method uses two main air compressors and one auxiliary air compressor to build a redundant air source system, ensuring uninterrupted air supply to the air supply system and stable air supply to the pneumatic clutch and gear lubrication device of the ball mill. It has high reliability and, through control distribution based on the pressure deviation rate, good pressure stabilization effect.

[0030] 2. The ball mill's centralized air supply system and pressure stabilization control method, the flexible adjustment of the variable frequency main air compressor and the intelligent start and stop of the auxiliary air compressor can greatly reduce ineffective operating time and achieve significant energy-saving effects. Moreover, the stable air source and pressure make the material flow in the ball mill uniform, extend the replacement cycle of vulnerable and consumable parts such as liners and steel balls, reduce the impact on the transmission system caused by unstable air pressure, and significantly reduce the equipment failure rate.

[0031] 3. The centralized air supply system and pressure stabilization control method of the ball mill is equipped with sound and light alarms under three working conditions. When the pressure of the air supply system is normal, the green light is always on and no alarm is given. When the pressure of the air supply system needs to be adjusted, the yellow light is displayed and no alarm is given. After the adjustment is completed, the green light is displayed and the system is in normal working condition. When the pressure of the air supply system fails and cannot be adjusted, the red light is buzzed and the alarm is given, so that the staff can grasp the working status of the system in real time and conduct manual intervention and adjustment in time, making the entire air supply system safer and more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the ball mill centralized air supply system and the voltage stabilization control method of the present invention;

[0033] Figure 2 This is a schematic diagram of the PLC control connection in the gas supply system of the present invention;

[0034] Figure 3 This is a flow chart of the pressure stabilization control of the pneumatic clutch in the air supply system of the present invention;

[0035] Figure 4 This is a flow chart of the voltage stabilization control of the gear lubrication device in the air supply system of the present invention.

[0036] In the figure: 101, ball mill drum; 102, synchronous motor; 103, pneumatic clutch; 104, gear lubrication device; 201, first air compressor; 202, first air compressor controller; 203, first pressure transmitter; 204, first electric ball valve; 205, first air source pipeline; 206, first check valve; 207, first air storage tank; 208, second air compressor; 209, second air compressor controller; 210, second pressure transmitter; 211, second electric ball valve; 212, second air source pipeline; 213, pressure reducing valve; 214, second check valve; 215, second air storage tank; 216. Pressure relief valve; 217. Third air compressor; 218. Third air compressor controller; 219. Third pressure transmitter; 220. Third air source pipeline; 221. First electric V-type ball valve; 222. Fourth air source pipeline; 223. Second electric V-type ball valve; 301. First air supply main pipe; 302. Second air supply main pipe; 401. First air supply branch pipe; 402. First electric stop valve; 403. Fourth pressure transmitter; 404. Second air supply branch pipe; 405. Second electric stop valve; 406. Fifth pressure transmitter; 501. PLC controller; 502. Sound and light alarm. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] See also Figure 1-2 A ball mill centralized gas supply system and pressure stabilization control method provided in this embodiment are composed of at least one ball mill unit, an air source system unit, a main pipeline unit, a branch pipeline unit and a control system unit.

[0039] Among them, the ball mill unit includes a ball mill drum 101, a synchronous motor 102, a pneumatic clutch 103 and a gear lubrication device 104; the pneumatic clutch 103 inflates or deflates the pneumatic tire under a stable and appropriate air source power to complete the connection or disconnection between the synchronous motor 102 and the ball mill drum 101. The air source pressure required by the pneumatic clutch 103 is 0.7~1.0MPa. The gear lubrication device 104 is used to spray lubricating oil on the surface of the meshing gear. The air source pressure required by the gear lubrication device 104 is 0.5~0.8MPa.

[0040] The air source system unit includes a first air compressor 201 and a second air compressor 208. The first and second air compressors 201 and 208 are the main air compressors, employing permanent magnet variable frequency screw air compressors. The first air compressor 201 primarily provides air for the pneumatic clutch 103, with the first air compressor controller 202 setting the loading pressure at 0.7 MPa and the unloading pressure at 1.0 MPa. The second air compressor 208 primarily provides air for the gear lubrication device 104, with the second air compressor controller 209 setting the loading pressure at 0.5 MPa and the unloading pressure at 0.8 MPa. The first air compressor 201 is connected to the first air storage tank 207 via a first air source pipeline 205. The first air source pipeline 205 at the exhaust end of the first air compressor 201 is connected in sequence to a first pressure transmitter 203 and a first electric ball valve 204. A first check valve 206 is connected to the first air source pipeline 205 at the air inlet end of the first air storage tank 207. The second air compressor 208 is connected to the second air storage tank 215 via a second air source pipeline 212. The second air source pipeline 212 at the exhaust end of the second air compressor 208 is connected in sequence to a second pressure transmitter 210 and a second electric ball valve 211. A second check valve 214 is connected to the second air source pipeline 212 at the air inlet end of the second air storage tank 215. A pressure reducing valve 213 is connected to the air inlet end of the second air storage tank 215. The outlet pressure of the pressure reducing valve 213 is set at 0.8 MPa to prevent the air supply pressure from exceeding 0.8 MPa when the third air compressor 217 assists in supplying air. The pressure reducing valve 213 is installed at the air inlet end of the second check valve 214. The exhaust end is connected to a pressure relief valve 216, which is connected in parallel to the second air supply main 302. The pressure relief valve 216 is set at 0.8 MPa, providing dual protection with the pressure reducing valve 213.

[0041] The air source system unit in this embodiment also includes a third air compressor 217, which is an auxiliary air compressor and adopts an industrial frequency screw air compressor; the exhaust port of the third air compressor 217 is connected to the third pressure transmitter 219; the loading pressure of the third air compressor controller 218 is set to 0.7MPa, and the unloading pressure is set to 1.0MPa, which is consistent with the pneumatic clutch 103 with a higher air pressure. The third air compressor 217 is connected in parallel with the first air compressor 201 and the second air compressor 208; the third air compressor 217 is connected to the rear end of the exhaust port of the first electric ball valve 204 on the first air source pipeline 205 through the third air source pipeline 220, and at the same time, is connected to the rear end of the exhaust port of the second electric ball valve 211 on the second air source pipeline 212 through the fourth air source pipeline 222; the third electric V-shaped ball valve 221 is connected to the third air source pipeline 220, and the fourth electric V-shaped ball valve 223 is connected to the fourth air source pipeline 222; the valve core design of the electric V-shaped ball valve provides an approximately linear flow characteristic, taking into account both switching and adjustment functions, and the linear adjustment function enables the auxiliary air source to smoothly enter the main air source to avoid pressure fluctuations.

[0042] In the above embodiment, the first electric V-type ball valve 221 and the second electric V-type ball valve 223 are opened in a staged manner. When the pneumatic clutch 103 requires auxiliary air supply, the pressure difference between the third pressure transmitter 219 and the first pressure transmitter 203 is compared in real time. When ΔP < 0.05 MPa, the first electric V-type ball valve 221 is opened. When the gear lubrication device 104 requires auxiliary air supply, the difference between the third pressure transmitter 219 and the second pressure transmitter 210 is compared in real time. When ΔP < 0.05 MPa, the second electric V-type ball valve 223 is opened. The purpose of controlling the pressure difference is to allow the compressed air in the auxiliary pipeline network to be smoothly integrated into the main pipeline network. The opening method of the first electric V-type ball valve 221 and the second electric V-type ball valve 223 is as follows: the valve is opened to 20% opening for the first second, and then linearly opened to 100% opening for 2 seconds.

[0043] The air source system unit in this embodiment is connected to the main pipeline unit and branch pipeline units. The branch pipeline units are arranged according to the number of ball mill units. The exhaust port of the first air storage tank 207 in the air source system unit is connected to the first air supply main pipe 301. The pneumatic clutch 103 is connected to the first air supply main pipe 301 via the first air supply branch pipe 401. The first air supply branch pipe 401 is connected to the first electric stop valve 402 and the fourth pressure transmitter 403 in sequence. The exhaust port of the second air storage tank 215 in the air source system unit is connected to the second air supply main pipe 302. The gear lubrication device 104 is connected to the second air supply main pipe 302 via the second air supply branch pipe 404. The second air supply branch pipe 404 is connected to the second electric stop valve 405 and the fifth pressure transmitter 406 in sequence.

[0044] The control system unit in this embodiment includes a PLC controller 501 and an audible and visual alarm 502. The PLC controller 501 is connected to the first air compressor controller 202, the first pressure transmitter 203, the first electric ball valve 204, the second air compressor controller 209, the second pressure transmitter 210, the second electric ball valve 211, the third air compressor controller 218, the third pressure transmitter 219, the first electric V-type ball valve 221, the second electric V-type ball valve 223, the first electric stop valve 402, the fourth pressure transmitter 403, the second electric stop valve 405, and the fifth pressure transmitter 406 through cables. The electric V-type ball valve and the pressure transmitter adopt 4-20mA analog. The analog signal input terminal is used, and the rest use digital signal input terminals. The sound and light alarm 502 is connected to the signal output terminal of the PLC controller 501. When the PLC controller 501 gives a corresponding control signal, the signal feedback can be performed through the sound and light alarm 502. For example, when the pressure of the gas supply system is normal, the green light is always on and no alarm is given. When the pressure of the gas supply system needs to be regulated, the yellow light is displayed and no alarm is given. After the regulation is completed, the green light is displayed and the normal working state is shown. If the pressure of the gas supply system fails and cannot be regulated, the sound and light alarm 502 is in an alarm state with a red light and a buzzer, so that the staff can carry out manual intervention and regulation in time. The alarm settings in three states make the entire gas supply system safer and more reliable.

[0045] See also Figure 3-4 In order to further better explain the above embodiment, the present invention also provides a pressure stabilization control method for a ball mill centralized air supply system, comprising the following steps:

[0046] S1: The PLC controller 501 collects pressure data from the fourth pressure transmitter 403 and the fifth pressure transmitter 406 in real time, and calculates the pressure drop rate ΔP / Δt of the first gas supply branch pipe 401 and the second gas supply branch pipe 404 respectively;

[0047] S2: Based on the ΔP / Δt data, the first gas supply branch pipe 401 and the second gas supply branch pipe 404 are respectively subjected to pressure stabilization control. The method is as follows:

[0048] (1) When ΔP / Δt is less than 0.01 MPa / s, the first electric stop valve 402 and the second electric stop valve 405 are in the primary control mode, and the first air compressor 201 and the second air compressor 208 are in auxiliary control mode through variable frequency speed regulation.

[0049] (2) When 0.01 MPa / s≤ΔP / Δt<0.03 MPa / s, the first air compressor 201 and the second air compressor 208 are controlled by variable frequency speed regulation, and the first electric stop valve 402 and the second electric stop valve 405 are controlled as auxiliary;

[0050] (3) When ΔP / Δt≥0.03MPa / s, or the pressure data of the fourth pressure transmitter 403 is less than 0.7MPa and the pressure data of the fifth pressure transmitter 406 is less than 0.5MPa, the third air compressor 217, the first electric V-type ball valve 221, and the second electric V-type ball valve 223 are started to compensate for the air supply;

[0051] (4) When the pressure data of the fourth pressure transmitter 403 and the fifth pressure transmitter 406 reach the maximum pressure setting value, the third air compressor 217 is turned off, and the first electric V-type ball valve 221 and the second electric V-type ball valve 223 are closed.

[0052] In the above method, when the pneumatic clutch 103 needs auxiliary air supply to start the third air compressor 217, the pressure difference between the third pressure transmitter 219 and the first pressure transmitter 203 is compared in real time. When ΔP is less than 0.05 MPa, the first electric V-type ball valve 221 is opened; when the gear lubrication device 104 needs auxiliary air supply to start the third air compressor 217, the difference between the third pressure transmitter 219 and the second pressure transmitter 210 is compared in real time. When ΔP is less than 0.05 MPa, the second electric V-type ball valve 223 is opened. The first electric V-type ball valve 221 and the second electric V-type ball valve 223 adopt a two-stage opening method: the valve is opened to 20% opening in the first 1 second, and then linearly opened to 100% opening in the next 2 seconds. The entire control process is accompanied by signal feedback from the sound and light alarm 502, so that the staff can timely grasp the working status of the system and ensure more efficient and safe operation of the entire system.

[0053] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0054] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A ball mill centralized air supply system, characterized by: It consists of at least one ball mill unit, an air source system unit, a main pipeline unit, a branch pipeline unit and a control system unit; The ball mill unit comprises a ball mill drum (101), a synchronous motor (102), a pneumatic clutch (103) and a gear lubricating device (104); the air source system unit comprises a first air compressor (201) and a second air compressor (208); the first air compressor (201) provides an air source for the pneumatic clutch (103); the pneumatic clutch (103) is used to complete the connection or disconnection between the synchronous motor (102) and the ball mill drum (101) under stable air source power; the first air compressor (201) is connected to a first air storage tank (207) via a first air source pipeline (205); the first air source pipeline (205) is connected to a first pressure transmitter (203) and a first electric ball valve (204) in sequence; The air inlet front end of the first air storage tank (207) is connected to the first check valve (206); the second air compressor (208) provides an air source for the gear lubrication device (104), and the gear lubrication device (104) is used to spray lubricating oil on the surface of the meshing gear. The second air compressor (208) is connected to the second air storage tank (215) through a second air source pipeline (212). The second air source pipeline (212) is connected to the second pressure transmitter (210) and the second electric ball valve (211) in sequence. The air inlet front end of the second air storage tank (215) is connected to the second check valve (214); the air source system unit also includes a third air compressor (217), and the exhaust port of the third air compressor (217) is connected to the third pressure transmitter (219); The air source system unit is connected to the main pipeline unit and the branch pipeline unit; the exhaust port of the first air storage tank (207) is connected to the first air supply main pipe (301); the pneumatic clutch (103) is connected to the first air supply main pipe (301) via the first air supply branch pipe (401); the exhaust port of the second air storage tank (215) is connected to the second air supply main pipe (302); the gear lubrication device (104) is connected to the second air supply main pipe (302) via the second air supply branch pipe (404); The control system unit comprises a PLC controller (501) and an audible and visual alarm (502); the PLC controller (501) is connected to the various electric control components in the gas source system unit and the branch pipeline unit via cables; the audible and visual alarm (502) is connected to the signal output end of the PLC controller (501) for audible and visual feedback alarm.

2. A ball mill centralized air supply system according to claim 1, characterized in that: The pneumatic clutch (103) requires an air source pressure of 0.7 to 1.0 MPa, and the gear lubrication device (104) requires an air source pressure of 0.5 to 0.8 MPa.

3. The ball mill centralized air supply system according to claim 1, characterized in that: The first air compressor (201) is provided with a first air compressor controller (202), the loading pressure of the first air compressor controller (202) is set to 0.7 MPa, and the unloading pressure is set to 1.0 MPa. The second air compressor (208) is provided with a second air compressor controller (209), the loading pressure of the second air compressor controller (209) is set to 0.5 MPa, and the unloading pressure is set to 0.8 MPa. The first air compressor (201) and the second air compressor (208) are main air compressors, and permanent magnet variable frequency screw air compressors are used. The third air compressor (217) is provided with a third air compressor controller (218), the loading pressure of the third air compressor controller (218) is set to 0.7 MPa, and the unloading pressure is set to 1.0 MPa. The third air compressor (217) is an auxiliary air compressor, and an industrial frequency screw air compressor is used.

4. The ball mill centralized air supply system according to claim 1, characterized in that: The third air compressor (217) is connected in parallel with the first air compressor (201) and the second air compressor (208). The third air compressor (217) is connected to the first air source pipeline (205) via a third air source pipeline (220) and is connected to the second air source pipeline (212) via a fourth air source pipeline (222). A first electric V-shaped ball valve (221) is connected to the third air source pipeline (220), and a second electric V-shaped ball valve (223) is connected to the fourth air source pipeline (222).

5. The ball mill centralized air supply system according to claim 1, characterized in that: The front end of the air inlet of the second air storage tank (215) is connected to a pressure reducing valve (213), and the rear end of the air outlet is connected to a pressure relief valve (216), and the pressure relief valve (216) is connected in parallel to the second air supply main pipe (302).

6. The ball mill centralized air supply system according to claim 1, characterized in that: The first gas supply branch pipe (401) is connected to a first electric stop valve (402) and a fourth pressure transmitter (403), and the second gas supply branch pipe (404) is connected to a second electric stop valve (405) and a fifth pressure transmitter (406).

7. The ball mill centralized air supply system according to claim 1, characterized in that: The electronic control components include a first air compressor controller (202), a first pressure transmitter (203), a first electric ball valve (204), a second air compressor controller (209), a second pressure transmitter (210), a second electric ball valve (211), a third air compressor controller (218), a third pressure transmitter (219), a first electric V-type ball valve (221), a second electric V-type ball valve (223), a first electric stop valve (402), a fourth pressure transmitter (403), a second electric stop valve (405), and a fifth pressure transmitter (406), wherein the electric V-type ball valve and the pressure transmitter use 4-20 mA analog signals, and the others use digital signals.

8. A method for controlling the pressure stabilization of a ball mill centralized air supply system according to claim 1, characterized in that: The following steps are involved: S1: collecting pressure data of the fourth pressure transmitter (403) and the fifth pressure transmitter (406) in real time through the PLC controller (501), and calculating the pressure drop rate ΔP / Δt of the first gas supply branch pipe (401) and the second gas supply branch pipe (404) respectively; S2: Based on the ΔP / Δt data, the first air supply branch pipe (401) and the second air supply branch pipe (404) are respectively subjected to pressure stabilization control, the method being as follows: (1) When ΔP / Δt is less than 0.01 MPa / s, the first electric stop valve (402) and the second electric stop valve (405) are in the main control mode, and the first air compressor (201) and the second air compressor (208) are in auxiliary control mode by variable frequency speed regulation; (2) When 0.01 MPa / s≤ΔP / Δt<0.03 MPa / s, the first air compressor (201) and the second air compressor (208) are controlled by variable frequency speed regulation, and the first electric stop valve (402) and the second electric stop valve (405) are controlled by auxiliary control; (3) When ΔP / Δt≥0.03MPa / s, or the pressure data of the fourth pressure transmitter (403) is less than 0.7MPa and the pressure data of the fifth pressure transmitter (406) is less than 0.5MPa, the third air compressor (217), the first electric V-type ball valve (221), and the second electric V-type ball valve (223) are started to compensate for the air supply; (4) When the pressure data of the fourth pressure transmitter (403) and the fifth pressure transmitter (406) reach the maximum pressure setting value, the third air compressor (217) is turned off, and the first electric V-type ball valve (221) and the second electric V-type ball valve (223) are closed.

9. The method for controlling the pressure stabilization of a ball mill centralized air supply system according to claim 8, characterized in that: When the pneumatic clutch (103) requires auxiliary air supply to start the third air compressor (217), the pressure difference between the third pressure transmitter (219) and the first pressure transmitter (203) is compared in real time. When ΔP is less than 0.05 MPa, the first electric V-type ball valve (221) is opened. When the gear lubrication device (104) requires auxiliary air supply to start the third air compressor (217), the difference between the third pressure transmitter (219) and the second pressure transmitter (210) is compared in real time. When ΔP is less than 0.05 MPa, the second electric V-type ball valve (223) is opened.

10. The method for controlling the pressure stabilization of a ball mill centralized air supply system according to claim 8, characterized in that: The first electric V-shaped ball valve (221) and the second electric V-shaped ball valve (223) adopt a two-stage opening method: the valve is opened to 20% opening in the first second, and then linearly opened to 100% opening in the next 2 seconds.

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