Working face and belt conveyor automation system

Whether the working face and belt conveyor automation system operate safely and reliably directly affects the economic benefits of the mine. To improve the system's reliability and safety, implementing centralized monitoring to achieve comprehensive protection and remote control of the system is essential. The safe and efficient operation of the working face "three-machine" system and the belt conveyor not only requires independent control subsystems for each equipment on the working face "three-machine" and individual belt conveyors but also needs a main control machine that can control and coordinate command of each subsystem. It involves centralized control of the main coal flow, ground dispatch monitoring and surveillance, and networked control of video surveillance. This is an important direction for the development of centralized control in the working face "three-machine" system, and it is also the foundation for unmanned operation in coal mine automation production. High production, quality, safety, energy conservation, labor-saving, reducing staff at posts, and ultimately achieving cost reduction and improving labor productivity to obtain maximum profits are the basis for coal enterprises to survive in competition in the future. Through automation construction to reduce staff and increase efficiency, lower costs, and improve labor productivity, the automation control of working face equipment is an important part of the intelligent construction of coal mines. For this purpose, our company has independently developed the working face and belt conveyor automation system. This system integrates the German Siemens S7 series programmable controllers and embedded system technology to achieve automated control of the "three-machine" and rubber belt transport on the coal mine working face. It has added a digital amplifying telephone function, uses the CAN bus for voice transmission, and adopts a "quick plug-in" connection method, making installation convenient and flexible.

1. Control Functions

The system has multiple control modes, including centralized control, local control, and maintenance control, with reliable interlocking functions between various control modes.

(1) Centralized Control Mode

The control main station operation panel on the working face has "Total Start" and "Total Stop" buttons to achieve sequential start-stop control of the trough belt, crusher, reloader, and scraper. The start delay and stop delay for the belt conveyor, crusher, reloader, and scraper can be set in the parameter setting screen.

(2) Local Control Mode

Operators can individually start and stop each device locally through the control main station and control substation, with a locking function. If the preceding device does not start, the subsequent device cannot start. If the preceding device stops, the subsequent device immediately stops. There are reliable interlocking relationships among the crusher, reloader, scraper, and belt conveyor on the working face.

(3) Maintenance Control Mode

Operators can arbitrarily start and stop each device locally through the control main station and control substation, without a locking function. This system can also control emulsion pumps and spray pumps, with reserved control interfaces being passive normally open interfaces. Pump control is not restricted by the operating mode, allowing for individual control and action, convenient and safe.

2. Startup Warning Function

The belt conveyor, crusher, reloader, and both the front and rear scrapers are equipped with a startup warning function, with adjustable warning times.

3. Voice Broadcasting System

The system's main unit is used in conjunction with amplifying telephones to achieve functions such as dialing, communication, and voice alarms along the belt conveyor and working face, with clear and loud sound. Belt conveyor inspection personnel can communicate with personnel along the line at any time, which facilitates belt maintenance and contact. An amplifying telephone is installed every 100 meters along the belt conveyor. In the comprehensive mining face, an amplifying telephone is installed every 15 meters, and mining communication tension cables are installed every 25 meters on the working face. Moreover, the working face amplifying telephones have an emergency stop interlock function. A local control amplifying telephone is installed at the head of both the reloader and the scraper, which not only has an emergency stop interlock function but also a local start-stop function. If new voice intercom control software is equipped in the ground monitoring center, voice communication with the working face can be achieved.

Communication method: Ethernet communication is used between the ground monitoring center and the working face.

4. Display Function

The control main station is equipped with a 10-inch color LCD display, and the substation has a 7-inch color LCD display. They can graphically, animatedly, and textually display the operating status of each device on the working face and the belt conveyor, and they can also display each kind of protection alarm information of the belt, as well as a historical alarm query function.

5. Belt Conveyor Protection Function

When a protection alarm occurs, it has a detailed alarm prompt function.

The belt conveyor has a real-time speed detection function.

The belt is equipped with sensors for coal accumulation, deviation, emergency stop, smoke, temperature, vibration, tearing, and speed. These sensors allow for detection and protection and enable alarm shutdown. On the control main station, it is possible to individually shield each protection of the trough belt according to actual conditions using the keyboard. When protection is shielded, if an alarm is triggered, it will only sound an alarm without stopping the machine.

Emergency stop pull switches with address coding are arranged along the belt, which display the fault location of the emergency stop sensor directly on the monitor and announce the fault location's voice alarm information after a protection action, facilitating fault clearance.

Deviation and tear sensors can be connected near an amplifying telephone and have address coding. After a protection action, the fault locations of the deviation sensor and tear sensor are directly displayed on the monitor, and their fault location's voice alarm information is announced, facilitating fault clearance.

6. Password Protection Function

Before setting parameters at the control main station, user login is required. This prevents unauthorized personnel from modifying parameters, effectively preventing non-professionals from adjusting settings.

7. Historical Data Query Function

Both the system monitoring upper computer and the PLC electronic control host support historical fault records, equipment operation records, equipment operation logs, equipment operation times, and other data report query functions. The upper computer system supports one-click export and printing functions. System data can be stored for at least one year.

8. Communication Function

The PLC system reserves an RS485 communication module and a standard TCP/IP protocol Ethernet interface, facilitating connections with smart power supply equipment or other intelligent devices on-site for data reading and writing functions. The PLC system communicates with the ground upper computer via fiber optic transmission. The entire network utilizes open Ethernet standard technology from the field of industrial automation. Devices can connect from the field level to the management level. It supports communication within the system range and supports mining engineering and configuration up to the field level, adhering to IT standards. This enhances the usability of the products and the maintainability of the system. It uses real-time Ethernet communication with a channel data response time of less than 150 milliseconds.

9. Video Surveillance System

The video camera captures live image information, uses fiber optic communication media, and uploads it to the ground monitoring center. This allows for remote monitoring of the working face and the operation of the belt conveyor, further enhancing the system's reliability and safety. Cameras use a fiber optic cascade connection method to connect directly to the mine's ring network switch and upload to the ground monitoring center.

Main functions:

(1) Information Collection: Camera-collected image signals are transmitted to the display screen in real time;

(2) Video Split Control Management: Simultaneously monitors multiple different image signals, enabling remote monitoring, remote access, and alarm linkage;

(3) Surveillance Function: Any video signal can be monitored via the display screen;

(4) Playback Function: Queries and plays back images saved by the digital video recorder in real time;

(5) Recording Function: The digital video recorder performs real-time and timed video recording;

(6) Switching Function: Automatically cycles through set images by time interval;

(7) Preview Function: Users can directly access IP cameras or video servers through IE browser;

(8) Video File Query Function: Video files from all cameras can be searched based on time, alarm records, etc.

10. Upper Computer Remote Monitoring System

The unattended remote monitoring station for the working face and belt conveyor is set up in the dispatch center, equipped with high-performance industrial computers, displays, upper computer software, configuration software, sound systems, gigabit switches, etc. The industrial computer with the upper computer configuration software can display in real-time the working conditions of the working face and belt conveyor system parameters such as temperature, smoke, coal accumulation, speed, emergency stop, deviation, tearing, motor temperature, vibration, etc., as well as equipment operation status, fault information, video linkage. It also allows for display, storage, remote operation, and communication with underground equipment, including dialing, calling, and music playback.

1.Control Equipment

(1) TH18 Mining Intrinsically Safe Console: Equipped with centralized control and video display storage functions, it features dual-screen display capabilities and a stainless steel casing. The TH12 mining intrinsically safe console is equipped with a 15-inch control LCD screen that can display the operating status and protection information of all belts in the system in graphics, animations, and text. It includes a hard disk recorder, an optical terminal, and a 21-inch monitor for video information storage and real-time display. It is also equipped with two metal mice, making operations simple and convenient. The control main station has functions such as dialing, calling, and voice alarms.

(2) KXJ127(A) Mining Explosion-proof and Intrinsically Safe Programmable Control Box: This high-tech integrated protection automation master control unit combines advanced German Siemens S7 series PLC technology, embedded technology, voice broadcasting technology, network communication technology, and computer technology. It is equipped with Ethernet, RS485 fieldbus, CAN fieldbus, and other data transmission interfaces, and is used in conjunction with the operation console.

(3) KXJ127 Mining Explosion-proof and Intrinsically Safe Programmable Control Box: This device incorporates the Siemens S7-1200 series PLC, enhanced with I/O expansion modules, analog acquisition modules, and standard communication processing modules. It achieves comprehensive monitoring and protection for the working face or conveyor belts. The control box is equipped with an embedded LCD display, which provides a graphic and intuitive display of each device's operating status and protection fault information, enhancing productivity at the working face. Additionally, this control box features various communication methods, including Ethernet, RS485, and CAN bus, allowing for seamless integration and data exchange with other actuators in the control systems of the working face or conveyor belts. Once seamlessly connected to the mine's ring network, it can perform data uploading and computer control functions.

(4) KTC169.1 Mining Explosion-proof and Intrinsically Safe Communication Controller: This unit is constructed using the new Siemens S7-200 Smart series PLC, along with digital expansion modules and communication modules. It features a 7-inch LCD display that can show the operating status and protection information of devices. It is equipped with capabilities such as dialing, calling, and voice alarms, enhancing communication and safety protocols within mining operations.

Associated Equipment 

(1) KTK18-D Mining Intrinsically Safe Amplifying Telephone: This is a specialized communication product designed for use in underground coal mines, open-pit coal mines, and coal preparation plants. It is primarily suited for locations with methane and coal dust explosion risks such as coal mine inclines, tunnels, belt faces, and comprehensive mining faces. The amplifying telephone enables dialing and communication along the line and can emit audio and visual alarm signals. It can also receive external signals for remote audio playback. When used in conjunction with a control main station, it can implement emergency stop interlocks along the line, enhancing safety measures across the mining site.

(2) KTK18-Z Mining Intrinsically Safe Amplifying Telephone: This communication device is specifically designed for underground coal mines, open-pit coal mines, and coal preparation plants. It is especially suitable for areas prone to methane and coal dust explosions such as mine inclines, tunnels, belt faces, and comprehensive mining faces. This device primarily facilitates dialing and communication along the line and can emit audio and visual alarm signals. It can also receive external signals for remote audio playback. When used in conjunction with a control main station, it enables emergency stop interlocks along the line and allows for local control of equipment start-up and shutdown, enhancing operational safety and flexibility in hazardous environments.

 

(3) DXJ127/24 Mining Explosion-proof and Intrinsically Safe Power Supply Box: This is an explosion-proof and intrinsically safe device for mining applications. The power supply box is compact and lightweight, making installation and relocation easy. It is primarily used in underground coal mine locations that contain explosive gases, providing power to mining intrinsically safe electrical equipment. The power supply operates by taking AC input voltage, which is then stepped down, rectified through a bridge rectifier, filtered by capacitors, and finally stabilized through a voltage regulation stage to deliver a steady power output. This design ensures that it can safely power essential equipment in hazardous environments.

(4) MHYPBV-8-X□□□ Mining Steel Wire Braided Tension Communication Cable: This cable uses domestically renowned brand shielded communication cable, known for its superior mechanical properties. It is resistant to chemical corrosion, flame retardant, weather-resistant, and has excellent electrical insulation properties. The aviation connectors used with this cable are manufactured in-house by our company, ensuring both quality and timeliness. This cable is ideally suited for rigorous and hazardous environments like those found in mining operations, providing reliable and secure communication capabilities.