Design of the receiving unit of the ultrasonic rail flaw detector

Abstract

The development of an ultrasonic fl aw detector receiving unit for rail monitoring includes theoretical and practical studies. Special attention is paid to the experimental determination of the characteristics of the ultrasonic piezoelectric sensor and the description of the receiving-amplifying path. A mock-up sample of an ultrasonic fl aw detector allows checking rails for defects and gives a tangible gain in dimensions compared to bulky analogues.The theoretical methods used were based on the principles of electrical engineering, electronic engineering, graphical analysis and the theory of automatic control.Experimental studies of the piezoelectric sensor allowed us to determine its main resonant frequency. The correct choice of parameters of the amplifier unit ensured accurate and reliable operation of the device. Practical tests of the fl aw detector using a special buffer sample of the rail made it possible to adjust its sensitivityThe input amplifier of the microvoltmeter V3-40 is taken as the basis of the receiving and amplifying path of the fl aw detector. The device includes the possibility of its use in conjunction with the converter. The structural diagram of the fl aw detector is presented. The electrical circuit of the input divider with the selection of the necessary resistances and the electrical circuit of the effective value meter with a description of all its elements are described.Operating modes and electronic circuits are selected according to reference data, taking into account their high reliability of operation. The use of analog integrated circuits in the circuit solution made it possible to increase the reliability and accuracy of the fl aw detector device, simplify its adjustment, reduce zero drift and improve the quality of the output signal.