阅读说明：本技术 一种煤矿用智能控制除尘系统及其控制方法 (Intelligent control dust removal system for coal mine and control method thereof ) 是由 长丹华 赵海兴 张德方 赵秀梅 惠忠文 刘霄龙 刘雄 刘小霞 高春 李瑞平 李志 于 2021-07-01 设计创作，主要内容包括：本发明属于煤矿除尘技术领域,具体涉及一种煤矿用智能控制除尘系统及其控制方法。本发明包括钻箱、多级除尘系统、隔爆变频电机、隔爆变频控制器和灰尘传感器；多级除尘系统与钻箱连接,对钻箱内的粉尘进入多级除尘系统后进行多级除尘；多级除尘系统与隔爆变频电机的输出端连接,隔爆变频电机的输入端与隔爆变频控制器的输出端连接,隔爆变频控制器的信号输入端与所述灰尘传感器连接,灰尘传感器将信号传输给隔爆变频控制器,隔爆变频控制器根据灰尘传感器的信号调节隔爆变频电机的工作电压,调节多级除尘系统的除尘风量。本发明能够根据灰尘浓度来“按需”送风,实现了系统对环境的自感知、自适应、自调节；能够记录频率变化并形成设备工作日志。(The invention belongs to the technical field of coal mine dust removal, and particularly relates to an intelligent control dust removal system for a coal mine and a control method thereof. The invention comprises a drill box, a multistage dust removal system, an explosion-proof variable frequency motor, an explosion-proof variable frequency controller and a dust sensor; the multistage dust removal system is connected with the drill box, and dust in the drill box is subjected to multistage dust removal after entering the multistage dust removal system; the multistage dust removal system is connected with the output end of the explosion-proof variable frequency motor, the input end of the explosion-proof variable frequency motor is connected with the output end of the explosion-proof variable frequency controller, the signal input end of the explosion-proof variable frequency controller is connected with the dust sensor, the dust sensor transmits a signal to the explosion-proof variable frequency controller, and the explosion-proof variable frequency controller adjusts the working voltage of the explosion-proof variable frequency motor and adjusts the dust removal air quantity of the multistage dust removal system according to the signal of the dust sensor. The invention can supply air as required according to the dust concentration, thereby realizing the self-perception, self-adaptation and self-adjustment of the system to the environment; frequency changes can be recorded and a device work log can be formed.)

1. The utility model provides an intelligent control dust pelletizing system for coal mine which characterized in that: the device comprises a drilling box (1), a multistage dust removal system, an explosion-proof variable frequency motor (7), an explosion-proof variable frequency controller (8) and a dust sensor (9);

the multistage dust removal system is connected with the drilling box (1), and dust in the drilling box (1) enters the multistage dust removal system and then is subjected to multistage dust removal;

the multistage dust removal system is connected with the output of flame proof variable frequency motor (7), and the input of flame proof variable frequency motor (7) is connected with the output of flame proof variable frequency controller (8), the signal input part of flame proof variable frequency controller (8) with dust sensor (9) are connected, and dust sensor (9) give flame proof variable frequency controller (8) with signal transmission, and flame proof variable frequency controller (8) adjust the operating voltage of flame proof variable frequency motor (7) according to the signal of dust sensor (9), adjust multistage dust removal system's the dust removal amount of wind.

2. The intelligent control dust removal system for coal mines according to claim 1, wherein: the multistage dust removal system comprises a primary dust removal box (2), a secondary dust removal box (3), a tertiary dust removal box (4) and a centrifugal fan (5);

the one end of one-level dust removal case (2) is bored case (1) and is connected, the other end and second grade dust removal case (3) are connected, and second grade dust removal case (3) are connected with centrifugal fan (5), and centrifugal fan (5) are connected with tertiary dust removal case (4), and the dust in boring case (1) gets into one-level dust removal case (2), second grade dust removal case (3), centrifugal fan (5) and tertiary dust removal case (4) in proper order and removes dust.

3. The intelligent control dust removal system for coal mines according to claim 2, wherein: the primary dust removal box (2) comprises a settling chamber (16), a rectifying plate (12), a baffle (13), an air inlet A (11), an air outlet F (14) and a dust collection hopper (15);

an air inlet A (11) and an air outlet F (14) are arranged on the settling chamber (16), a rectifying plate (12) is arranged in the settling chamber (16) at a position close to the air inlet A (11), an ash collecting hopper (15) is arranged at the bottom of the settling chamber (16), and a baffle plate (13) which is vertically arranged is arranged in the settling chamber (16);

the air inlet A port (11) is connected with the drill box (1) through a pipeline, and the air outlet F port (14) is connected with the secondary dust removal box (3) through a pipeline.

4. The intelligent control dust removal system for coal mines according to claim 3, wherein: the secondary dust removal box (3) comprises a box body, an air outlet pipe (17) and guide vanes (18);

an air inlet E is formed in the box body and connected with an air outlet F (14) of the primary dust removal box (2);

one part of the air outlet pipe (17) is positioned in the box body, the other part of the air outlet pipe is positioned at the top of the box body, an air outlet G port is formed in the top end of the air outlet pipe (17), and the air outlet G port is connected with the centrifugal fan (5).

5. The intelligent control dust removal system for coal mines according to claim 4, wherein: the centrifugal fan (5) is provided with an air outlet D and an air suction inlet C;

the three-stage dust removal box (4) is provided with an air inlet H, and a filter cylinder is arranged inside the three-stage dust removal box (4);

an air suction port C of the centrifugal fan (5) is connected with an air outlet G of the second-stage dust removal box (3), and an air outlet D of the centrifugal fan (5) is connected with an air inlet H of the third-stage dust removal box (4).

6. The intelligent control dust removal system for the coal mine according to any one of claims 1-5, wherein: the system further comprises an explosion-proof flash signal lamp (10), and the explosion-proof flash signal lamp (10) is connected with a signal input end of an explosion-proof variable frequency controller (8).

7. The intelligent control dust removal system for coal mines according to claim 6, wherein: the internal control element of the flameproof variable-frequency controller (8) is a PLC or a single chip microcomputer, and the flameproof variable-frequency controller (8) is internally provided with a storage function and used for recording working frequency changes and outputting working logs in real time.

8. The intelligent control dust removal system for coal mines according to claim 7, wherein: the primary dust removal box (2) is arranged at the front end of the whole machine of the system;

the secondary dust removal box (3), the explosion-proof variable frequency motor (7), the explosion-proof variable frequency controller (8) and the tertiary dust removal box (4) are arranged at the rear part of the whole machine of the system;

the dust sensor (9) and the explosion-proof flash signal lamp (10) are arranged in a cab of the system.

9. The intelligent control dust removal system for coal mines according to claim 8, wherein: the explosion-proof variable frequency motor (7) is connected with the centrifugal fan (5) through a coupler (6);

the explosion-proof variable frequency controller (8) is connected with the explosion-proof variable frequency motor (7) through a mining cable, and the explosion-proof variable frequency controller (8) is directly fixed on a rack of the whole machine through bolts;

the primary dust removal box (2) is fixed on a frame cross beam of the whole machine through bolts.

10. The control method of the intelligent control dust removal system for the coal mine according to claim 1, characterized in that: the dust sensor (9) converts the collected light intensity relative attenuation rate into a voltage signal U, the U is converted into a digital quantity V in the explosion-proof variable-frequency controller (8) and is compared with a preset value in the explosion-proof variable-frequency controller (8), the input of the explosion-proof variable-frequency controller (8) is changed according to the comparison value, the output frequency X and the output voltage V of the explosion-proof variable-frequency controller (8) are controlled, the rotating speed of the explosion-proof variable-frequency motor (7) is changed, and the air volume of the centrifugal fan (5) is controlled.

Technical Field

The invention belongs to the technical field of coal mine dust removal, and particularly relates to an intelligent control dust removal system for a coal mine and a control method thereof.

Background

In recent years, with the acceleration of mechanization of a domestic fully-mechanized coal mining and fully-mechanized excavation working face, most of equipment directly related to dust production is additionally provided with a dust removal device in the face of high dust influence caused by high-degree mechanical production of a coal mine. At present, however, the existing domestic dust removal device can not realize 'on-demand' air supply according to the content of dust in underground air, so that a dust removal fan is always worn in an idle running manner, and resources are wasted; secondly, the main factor causing the silicosis of the first-line miners is the respiratory dust containing free silicon dioxide generated in the production process, and no underground equipment for pre-warning that the dust concentration exceeds the standard exists in China at present; at present, mining equipment generally lacks detailed records of basic data such as the starting rate, the use frequency, the period use duration, the residual service life and the like, and certain obstacles are formed for the realization of intellectualization, service life evaluation, fault prediction and equipment group cooperative control of the equipment.

Disclosure of Invention

The invention aims to solve the problems and provides an intelligent control dust removal system for a coal mine and a control method thereof.

The invention is realized by adopting the following technical scheme: an intelligent control dust removal system for a coal mine and a control method thereof comprise a drill box, a multistage dust removal system, an explosion-proof variable frequency motor, an explosion-proof variable frequency controller and a dust sensor;

the multistage dust removal system is connected with the drill box, and multistage dust removal is carried out on dust in the drill box after the dust enters the multistage dust removal system;

the multistage dust removal system is connected with the output end of the explosion-proof variable frequency motor, the input end of the explosion-proof variable frequency motor is connected with the output end of the explosion-proof variable frequency controller, the signal input end of the explosion-proof variable frequency controller is connected with the dust sensor, the dust sensor transmits a signal to the explosion-proof variable frequency controller, and the explosion-proof variable frequency controller adjusts the working voltage of the explosion-proof variable frequency motor and adjusts the dust removal air quantity of the multistage dust removal system according to the signal of the dust sensor.

Further, the multistage dust removal system comprises a primary dust removal box, a secondary dust removal box, a tertiary dust removal box and a centrifugal fan;

the one end of one-level dust removal case is bored the case and is connected, the other end and second grade dust removal case and be connected, and the second grade dust removal case is connected with centrifugal fan, and centrifugal fan is connected with tertiary dust removal case, and the dust that bores the incasement gets into one-level dust removal case, second grade dust removal case, centrifugal fan and tertiary dust removal case in proper order and removes dust.

Furthermore, the primary dust removal box comprises a settling chamber, a rectifying plate, a baffle, an air inlet A, an air outlet F and a dust collecting hopper;

an air inlet A and an air outlet F are formed in the settling chamber, a rectifying plate is arranged at a position, close to the air inlet A, in the settling chamber, an ash collecting hopper is arranged at the bottom of the settling chamber, and a vertically arranged baffle is arranged inside the settling chamber;

the air inlet A is connected with the drill box through a pipeline, and the air outlet F is connected with the secondary dust removal box through a pipeline.

Further, the secondary dust removal box comprises a box body, an air outlet pipe and guide vanes;

an air inlet E is formed in the box body and connected with an air outlet F of the primary dust removal box;

one part of the air outlet pipe is positioned in the box body, the other part of the air outlet pipe is positioned at the top of the box body, an air outlet G port is formed in the top end of the air outlet pipe, and the air outlet G port is connected with the centrifugal fan.

Further, the centrifugal fan is provided with an air outlet D and an air suction inlet C;

the three-stage dust removal box is provided with an air inlet H, and a filter cylinder is arranged in the three-stage dust removal box;

and the air inlet C of the centrifugal fan is connected with the air outlet G of the second-stage dust removal box, and the air outlet D of the centrifugal fan is connected with the air inlet H of the third-stage dust removal box.

Furthermore, the system also comprises an explosion-proof flash signal lamp, and the explosion-proof flash signal lamp is connected with the signal input end of the explosion-proof variable frequency controller.

Furthermore, an internal control element of the explosion-proof variable frequency controller is a PLC or a single chip microcomputer, and the explosion-proof variable frequency controller is internally provided with a storage function and used for recording working frequency changes and outputting working logs in real time.

Furthermore, the primary dust removal box is arranged at the front end of the whole machine of the system;

the secondary dust removal box, the explosion-proof variable frequency motor, the explosion-proof variable frequency controller and the tertiary dust removal box are arranged at the rear part of the whole machine of the system;

the dust sensor and the explosion-proof flash signal lamp are arranged in a cab of the system.

Further, the explosion-proof variable frequency motor is connected with the centrifugal fan through a coupler;

the explosion-proof variable frequency controller is connected with the explosion-proof variable frequency motor through a mine cable, and the explosion-proof variable frequency controller is directly fixed on a rack of the whole machine through bolts;

and the primary dust removal box is fixed on a frame cross beam of the whole machine by using bolts.

A control method of an intelligent control dust removal system for a coal mine is characterized in that a dust sensor converts a collected light intensity relative attenuation rate into a voltage signal U, the U is converted into a digital quantity V in an explosion-proof variable frequency controller and is compared with a preset value in the explosion-proof variable frequency controller, and the input of the explosion-proof variable frequency controller is changed according to a comparison numerical value, so that the output frequency X and the output voltage V of the explosion-proof variable frequency controller are controlled, the rotating speed of an explosion-proof variable frequency motor is further changed, and the air volume of a centrifugal fan is controlled.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the method, the dust concentration of air in the surrounding environment can be monitored in real time, converted into an electric signal, compared with the data preset by a program in the explosion-proof variable frequency controller, and finally, the centrifugal fan can automatically adjust the air volume change according to the concentration of the particles in the field to be measured through the logic change of frequency, voltage and rotating speed, so that air supply according to requirements is realized; the system can be automatically started to carry out flash alarm according to the environment dust concentration condition, so that the self-perception, self-adaptation and self-adjustment of the system to the environment are realized; meanwhile, the system can record the frequency change trend in real time and form an equipment working log, so that the service time and frequency of the equipment in a cycle are judged, a reliable data basis is provided for equipment on-time rate statistics, residual life prediction and intelligent internet of things, and a reliable basis is provided for equipment intelligent construction;

2. the system has the characteristics of self-sensing, self-adaption, self-regulation, high dust removal, stepless speed regulation, no flushing, energy conservation and the like; the multi-stage dust removal box, the sensor and the intelligent system can effectively reduce the dust concentration of a working surface, so that the system can save energy and reduce production cost on the premise of ensuring the dust removal effect, and can give an early warning on the excessive concentration of respiratory dust particles in the environment, reduce pneumoconiosis and coal dust explosion probability of a front-line operator and ensure the occupational health and safety of front-line workers; meanwhile, the intelligent system does not need manual intervention in the whole working process, improves the working efficiency, provides a digital analysis basis for equipment, and has important significance for promoting the intelligent development of coal mine equipment.

3. According to the control method, a voltage signal U (analog quantity) acquired by a dust sensor is converted into a digital quantity V in an explosion-proof variable frequency controller PLC, the digital quantity V is compared with a set value in the explosion-proof variable frequency controller PLC, the input end of a frequency converter is changed by using a comparison numerical value, so that the output frequency X and the output voltage V of the explosion-proof variable frequency controller are controlled, the rotating speed of a variable frequency motor is changed, and the purposes that the centrifugal fan automatically adjusts the air quantity according to the concentration of particles in a field to be detected and performs early warning are achieved.

Drawings

FIG. 1 is a schematic view of the installation of the present system on a bolter;

FIG. 2 is a schematic diagram of the dedusting principle of the system;

FIG. 3 is a schematic structural diagram of a primary dust removal box of the system;

FIG. 4 is a schematic structural diagram of a secondary dust removal box of the system;

FIG. 5 is a flowchart of the present control method;

FIG. 6 is an electrical operation diagram of the present control method;

in the figure: the device comprises a drilling box 1, a primary dust removal box 2, a secondary dust removal box 3, a tertiary dust removal box 4, a centrifugal fan 5, a coupler 6, a flame-proof variable frequency motor 7, a flame-proof variable frequency controller 8, a dust sensor 9, a flame-proof flash signal lamp 10, an air inlet A port 11, a rectifying plate 12, a baffle 13, an air outlet F port 14, an ash collecting hopper 15, a settling chamber 16, an air outlet pipe 17 and a guide vane 18.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for matching with the disclosure of the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions under which the present invention can be implemented, so that the present invention has no technical significance, and any structural modification, ratio relationship change, or size adjustment should still fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.

Referring to fig. 1 to 5, the present invention provides a technical solution: an intelligent control dust removal system for a coal mine and a control method thereof comprise a drill box 1, a multistage dust removal system, an explosion-proof variable frequency motor 7, an explosion-proof variable frequency controller 8 and a dust sensor 9;

the multistage dust removal system is connected with the drilling box 1, and multistage dust removal is carried out on dust in the drilling box 1 after the dust enters the multistage dust removal system;

the multistage dust removal system is connected with the output end of the explosion-proof variable frequency motor 7, the input end of the explosion-proof variable frequency motor 7 is connected with the output end of the explosion-proof variable frequency controller 8, the signal input end of the explosion-proof variable frequency controller 8 is connected with the dust sensor 9, the dust sensor 9 transmits a signal to the explosion-proof variable frequency controller 8, and the explosion-proof variable frequency controller 8 adjusts the working voltage of the explosion-proof variable frequency motor 7 according to the signal of the dust sensor 9 and adjusts the dust removal air volume of the multistage dust removal system.

The multistage dust removal system comprises a primary dust removal box 2, a secondary dust removal box 3, a tertiary dust removal box 4 and a centrifugal fan 5;

the one end of one-level dust removal case 2 is bored case 1 and is connected, the other end and second grade dust removal case 3 and be connected, and second grade dust removal case 3 is connected with centrifugal fan 5, and centrifugal fan 5 is connected with tertiary dust removal case 4, and the dust that bores in the case 1 gets into one-level dust removal case 2, second grade dust removal case 3, centrifugal fan 5 and tertiary dust removal case 4 in proper order and removes dust.

The primary dust removal box 2 comprises a settling chamber 16, a rectifying plate 12, a baffle 13, an air inlet A port 11, an air outlet F port 14 and a dust collection hopper 15;

an air inlet A port 11 and an air outlet F port 14 are arranged on the settling chamber 16, a rectifying plate 12 is arranged at a position, close to the air inlet A port 11, in the settling chamber 16, an ash collecting hopper 15 is arranged at the bottom of the settling chamber 16, and a baffle 13 which is vertically arranged is arranged in the settling chamber 16;

the air inlet A port 11 is connected with the drilling box 1 through a pipeline, and the air outlet F port 14 is connected with the secondary dust removal box 3 through a pipeline.

The secondary dust removal box 3 comprises a box body, an air outlet pipe 17 and guide vanes 18;

an air inlet E is formed in the box body and connected with an air outlet F14 of the primary dust removal box 2;

one part of the air outlet pipe 17 is positioned in the box body, the other part of the air outlet pipe is positioned at the top of the box body, an air outlet G port is formed in the top end of the air outlet pipe 17, and the air outlet G port is connected with the centrifugal fan 5.

The centrifugal fan 5 is provided with an air outlet D and an air suction inlet C;

the three-stage dust removal box 4 is provided with an air inlet H, a filter cylinder is arranged inside the three-stage dust removal box 4, and the three-stage dust removal box 4 is fixed on the rack and connected with the centrifugal fan through a bolt;

5 inlet scoop C mouths of centrifugal fan with the air outlet G mouth of second grade dust removal case 3 is connected, and 5 air outlet D mouths of centrifugal fan are connected with tertiary dust removal case 4's air intake H mouth.

The system further comprises an explosion-proof flash signal lamp 10, the explosion-proof flash signal lamp 10 is connected with a signal input end of an explosion-proof variable frequency controller 8, if the explosion-proof variable frequency controller 8 monitors that the concentration of the respiratory dust exceeds a preset value, the explosion-proof flash signal lamp 10 can be started to give a flash alarm, and the explosion-proof flash alarm lamp 10 is controlled to be started and stopped by the explosion-proof variable frequency controller 8.

The internal control element of the flameproof variable-frequency controller 8 is a PLC or a single chip microcomputer, and the flameproof variable-frequency controller 8 has a storage function and is used for recording working voltage and frequency change in real time and outputting a working log.

The primary dust removal box 2 is arranged at the front end of the whole machine of the system;

the secondary dust removal box 3, the explosion-proof variable frequency motor 7, the explosion-proof variable frequency controller 8 and the tertiary dust removal box 4 are arranged at the rear part of the whole machine of the system;

the dust sensor 9 and the explosion-proof flash signal lamp 10 are arranged in a cab of the system.

The output shaft of the explosion-proof variable frequency motor 7 is connected with the input shaft of the centrifugal fan 5 through a coupler 6;

the explosion-proof variable frequency controller 8 is connected with the explosion-proof variable frequency motor 7 through a mine cable, and the explosion-proof variable frequency controller 8 is directly fixed on a rack of the whole machine through bolts;

the first-stage dust removal box 2 is fixed on a frame cross beam of the whole machine through bolts.

A control method of an intelligent control dust removal system for a coal mine is characterized in that a dust sensor 9 converts a collected light intensity relative attenuation rate into a voltage signal U, the U is converted into a digital quantity V in an explosion-proof variable frequency controller 8 and is compared with a preset value in the explosion-proof variable frequency controller 8, the input of the explosion-proof variable frequency controller 8 is changed according to a comparison numerical value, so that the output frequency X and the output voltage V of the explosion-proof variable frequency controller 8 are controlled, the rotating speed of an explosion-proof variable frequency motor 7 is changed, and the air quantity of a centrifugal fan 5 is controlled.

The dust sensor 9 provides data signals for the explosion-proof variable frequency controller 8.

The explosion-proof variable frequency controller 8 is connected with the explosion-proof variable frequency motor 7 and the explosion-proof flash signal lamp 10 through a mine cable, and the explosion-proof variable frequency motor 7 and the explosion-proof variable frequency controller 8 are directly fixed on the rack through bolts.

And the explosion-proof variable frequency controller 8 is connected with the dust sensor 9 through an intrinsic safety cable.

And the explosion-proof variable frequency motor 7 is connected with the centrifugal fan 5 and the explosion-proof variable frequency controller 8 through a mine cable.

The two-stage dust removal box 2 is fixed on two sides of the middle rear part of the whole machine through bolts, and the two-stage dust removal box 2 further comprises a dust discharging oil cylinder, a box body, and a conical cylinder, a helical blade, an air outlet cylinder and other parts which are arranged in the box body.

The primary dust removal box 2 is fixed on a fixed slide rail through screws, and an air inlet A port 11 of the primary dust removal box is connected with an air outlet B port of the drill box 1 through a hose and serves as a dust suction inlet.

The explosion-proof variable frequency controller 8 adjusts the voltage output frequency according to the frequency modulation control signal sent by the dust sensor 9, so as to adjust the working voltage of the explosion-proof variable frequency motor 7 and further control the rotating speed of the centrifugal fan 5; meanwhile, when the explosion-proof variable frequency controller 8 monitors that the concentration of the respiratory dust exceeds a preset threshold value, the explosion-proof flash signal lamp 10 is automatically connected to carry out concentration exceeding early warning.

This system can monitor the full dust and the respiratory dust concentration in the surrounding environment through dust sensor 9, and dust sensor 9 can show current monitoring data from taking the display screen. Firstly, when the monitored total dust concentration or the monitored respiratory dust concentration exceeds a preset value, the explosion-proof variable frequency controller 8 automatically starts the multistage dust removal system to perform air suction and dust removal, and meanwhile, the system can perform air volume response adjustment in real time according to the field dust concentration; secondly, if the concentration of the respiratory dust continuously exceeds the standard, the explosion-proof flash signal lamp 10 can flash for early warning to remind an operator to pay attention to safety protection; and thirdly, the flameproof variable frequency controller 8 has a storage function, can automatically record frequency change and output a working log, and provides a reliable data basis for equipment on-time rate statistics, residual life prediction and intelligent Internet of things.

As shown in fig. 6, the equipment is connected (left side of the dotted line), the flameproof flash signal lamp, the dust sensor and the flameproof variable frequency motor are connected with the frequency conversion system by using cables, a power module in the frequency conversion system supplies power to the relay, the PLC and the frequency conversion module, the PLC receives a signal of the dust sensor, and the signal is converted into an electric signal through data processing to drive the relay to open and close, so that the flameproof flash signal lamp alarms; controlling the variable frequency module to enable the variable frequency motor to rotate;

data processing (dotted line right side), PLC handles the dust sensor signal that receives, specifically is: firstly, converting the analog quantity into digital quantity, then comparing the digital quantity with a set standard value, controlling the output of the PLC according to a logic judgment result, and storing the result in a data mode.

The working principle of the invention is as follows:

1. the control principle of the system is as follows:

the dust sensor indirectly monitors the concentration of the particulate matters in the environment of the measured field by comparing the intensity change of the parallel monochromatic light passing through the measured particle field and calculating the attenuation rate of the light (the attenuation rate of the electric signal reflects the relative concentration of the dust in the measured field to a certain extent after being photoelectrically converted into an electric signal), converts the electric signal into a voltage signal U (analog quantity) and transmits the voltage signal U to the flameproof variable-frequency controller 8;

the explosion-proof variable frequency controller 8 converts the received voltage signal U (analog quantity) into a digital quantity V in the system, compares the digital quantity V with a preset parameter (regulating gear) in the system, outputs the frequency X and the output voltage V according to a comparison value and a preset program, and starts an explosion-proof variable frequency motor, the explosion-proof variable frequency motor changes the output rotating speed along with the change of the frequency X and the voltage V of the received explosion-proof variable frequency controller 8 so as to control the rotating speed of the centrifugal fan 5 and generate negative pressure in the system, and under the action of the negative pressure, a large amount of particles generated by operation pass through a hollow drill rod and a hollow core shaft of the drill box 1 and flow through an air inlet A11 to enter the primary dust removal box 2.

2. The dust removal principle of this system:

the primary dust removal box 2 can collect particles with equivalent diameter larger than 40-50 mu m based on the gravity dust removal principle, and the particles with equivalent diameter smaller than 40-50 mu m enter the secondary dust removal box 3 along an opening E; the secondary dust removal box 3 can carry out secondary trapping on particles with the particle size of more than 5-16 mu m by utilizing the centrifugal force principle; the rest particles with the particle size of less than 5-16 μm flow through the centrifugal wind 5 and enter the third-stage dust removal box 4 through an air inlet H of the third-stage dust removal box 4; the three-stage dust removal box 4 finely filters particles with the particle size of more than 0.5 mu m by using a filter cylinder filtering principle; after filtering, the clean air is discharged from the outlet of the three-stage dust removing box 4.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.