Research And Design Of Intrinsic Safety Ultrasonic Reverse Warning System In Coal Mine

As one of the most important energy and mineral resources in China,the exploitation of coal resources is huge and accounts for a very high proportion of domestic energy consumption.Coal mine resources maintain the lifeline of the country and are of great significance to the development of the national economy.Therefore,coal mine production conditions and production safety have become a vital link.Nowadays,the working environment of underground coal mine has been greatly improved,but due to the special environment and complex operation conditions,there are still many potential safety hazards in the mine.As a hub to maintain the connection between working units and upper and lower wells,the safety level of mine transportation needs to be improved urgently.In order to assist the driver to drive safely,it is necessary to design a reverse early warning system suitable for coal mine environmental conditions to assist the driver to obtain surrounding information.Under the conditions of poor light conditions in the mine,more impurities such as dust and smoke in the air and different working faces,ultrasonic ranging methods with strong antiinterference ability and good adaptability to the environment stand out.The energy generated by the pulse step-up transformer coil in the traditional reversing early warning system greatly exceeds the limit of the ignition energy of gas explosion while increasing the driving voltage,which can not meet the explosion-proof requirements of mine operation.In order to ensure its safe and stable operation in explosive environment,it is necessary to design the overall circuit and develop a set of safe and reliable mining intrinsically safe ultrasonic reversing early warning system.This subject makes a comprehensive analysis from the aspects of ultrasonic characteristics,ultrasonic ranging method,ultrasonic attenuation and absorption and the development of ultrasonic transducer;At the same time,it explains the intrinsic safety theory corresponding to the explosion-proof requirements of coal mine underground operation,and makes a thorough analysis from the aspects of electrical discharge form,discharge law of basic circuit,arc discharge mathematical model of intrinsically safe circuit,spark energy of intrinsically safe circuit and non explosive evaluation method of intrinsically safe circuit,which provides a reference for circuit intrinsically safe design.The detailed scheme design of the mine intrinsically safe ultrasonic ranging system is carried out,the harm of the traditional mid cycle transformer driving circuit in the explosive environment is analyzed and calculated,the transformer free driving scheme is designed and its intrinsically safe performance is verified;The two common bus modes of data communication are analyzed and compared,and the communication scheme based on LIN bus is determined;The channel selection module is designed to realize multi-channel cooperative detection to ensure that the ranging system can normally play its ranging and early warning role in different occasions;The auxiliary circuit is designed to realize the alarm function and distance display,improve the auxiliary function of the ranging system,and feed back the ranging information to the driver in real time.This paper introduces the software development environment required by the intrinsically safe ultrasonic reverse warning system,analyzes and designs the structure and function of the ultrasonic ranging system,and studies and designs the principle and structure of the main control unit;The ultrasonic transceiver circuit based on ranging chip is designed.The ranging parameters are adjusted and determined through software design,so that it can reliably complete the tasks of ultrasonic transmitting and echo receiving;The system ranging process is designed,so that the intrinsically safe ultrasonic reverse warning system can correctly play its ranging and early warning functions according to the instructions.Build the experimental platform of mine intrinsic safety ultrasonic reverse warning system,and test the LIN bus communication interface to ensure the normal operation of the communication module;The accuracy of the measuring system is improved by the experiment;Ultrasonic ranging experiments are carried out under different conditions,and satisfactory ranging results are obtained after eliminating interference;Using ultrasonic transducers with different frequencies to carry out ranging experiments,and compare their effects;Finally,the58 khz ultrasonic transducer is used to carry out the ranging and reliability experiment of the system,which can realize the effective distance measurement within the range of 250 ～2700mm.The ranging blind area is small,and the measurement error is within ± 30 mm,which fully meets the needs of reversing early warning.The mine intrinsic safety ultrasonic reversing early warning system studied and designed in this subject puts forward an effective scheme to improve the safety of mine transportation.The system has good ranging effect,fast response speed and strong reliability.It has important reference significance for guiding the safety of coal mine production and transportation.