Development Of The Condition Monitoring And Fault Diagnosing System Used In The Conveying Equipments Installed In The Fully-mechanized Coal Face

The project in this thesis is one important part of the project "super heavy armoured face conveyor, the stageloader and their key technology" (serial number:2007BAB13B01), which is the fifth sub-topic of the project" a complete range of the equipments and key technology in the fully-mechanized coal face with capacity of annual production of 10 million tons", sponsored by the National Key Technology R&D Program of China during the Eleventh Five-year Plan Period. The work is proposed in accordance with the lack of the condition monitoring and fault diagnosing system for the conveying equipments in coal face. According to field requirements and the target of building an underground unattended and full-automated face, a monitoring and diagnosing system has been developed based on the Programmable Logic Controller (PLC) and then the laboratory debugging and field debugging have been completed. Two systems have been being applied to the fully-mechanized faces in Gushuyuan and Xiegou Collieries which belong to Jincheng Anthracite Mining Group and Xishan Coal Electricity Group respectively. It has been shown by field running that the systems have been reached the condition monitoring and fault diagnoses for gearboxes and motors used in armored face conveyors, the crusher and the stageloader. The main contents of this thesis are as follows:After literature reviewing and site investigation, the developmental trend of the monitoring system and fault diagnosing technology in the coal mine is conscientiously analyzed. The component and operation modes of different conveying equipments are synthesized in detail, and functions and structure of the monitoring systems are seriously determined. The system is composed of a master station and several slave stations, which forms a condition monitoring and fault diagnosing local network system. The master station can monitor and control the slave stations remotely. The slave stations can monitor the operating condition locally and make primary fault diagnoses. They can also be singly used. In order to satisfy monitoring requirements in different coal faces, the master station or slave stations can be freely composed, and the system supports multiple conmmunication protocols.Considering the requirements of the standards for electrical apparatus used in underground, the system hardware circuits are designed and developed based on PLC control core. The HMI is equipped as a platform for interaction between human and system information. By means of multivariate information fusion technology, the operating conditions of unerground equipments, such as high-speed and low-speed bearing temperature of the gearbox, oil temperature, oil level of the gearbox, winding temperature, front bearing and rear bearing temperature of the motor, flow rate and pressure of the cooling water, can be monitored locally and remotely. The isolated safety barriers are used as intrinsic safety circuits.The application programs of the master station and slave stations are compiled by modular programming method, which include several subroutines such as communication subroutine, analog acquisition and processing subroutine, HMI subroutine, fault diagnosing subroutine, alarm subroutine and so on. The programs of display screens are also successfully designed.The common faults mechanisms of the conveying equipments are intensively studied. A fault diagnosing model based on the Back Propagation (BP) neural network and the D-S evidence theory is developed according to the information from monitoring systems. The possibility of predicting faults using the BP network is verified by experiments, the reliability and accuracy of fault diagnoses are also improved by the D-S theory in laboratory. All of these provide a theoretical foundation for fault diagnoses and prediction of gearboxes and motors installed in the conveying equipments.The system debugging has been finished in laboratory, and the results indicate that the performance of the system can satify the expected requirements. The monitoring system has been developed into products and debugged in the field (including on ground and in undergroud). Products have been successfully applied in two fully-mechanized faces. It has been verified by lab experiments, field debugging and underground operation that the system is of many advantages such as simple structure and reliable operation. The system has strong abilities to measure the information accurately, process them quickly and diagnose faults correctly for the underground conveying equipments, which laid a solid foundation for building the underground unattended and fully-automated coal face, and making the safety early-warning mechanism for underground equipments, as well as provide valuable experience for mygs-digital mine in future.