Selection and experimental study of the linear displacement converter for the automated monitoring system of mine roofs

The justification of the linear displacement sensors installation in mine workings is described in this paper. The required technical characteristics of the sensors are given. The main types of primary linear displacement converters are presented. The choice of inductive solenoid-type converters and sensors based on linear differential transformers (LVDT) is justified. The advantages and disadvantages of inductive transducers, their accuracy and measurement limits are described, and measuring methods of inductance of the solenoid-type transducers and the converter output signal based on LVDT are considered. The results of sensors experimental studies based on the solenoid-type inductive transducers are presented.

Nonlinear Deformation of a Pressure Diaphragm in Contact With a Piston

The problem of a shallow shell of revolution type diaphragm experiencing large deflections while being in contact with a centrally located piston is solved for some typical cases of pressure-displacement converter designs. The configuration and size of the contact area between diaphragm and piston is pressure dependent. Marguerres equations were assumed to be applicable and were solved by successive integration. The piston is assumed to be rigid, but supported by a linear spring.