Electrostatic, noncontact, continuous, and real-time velocity measurements in pneumatic transport pipes

An electrostatic, noncontact method for measuring the average velocity of particulate flow while conveying pneumatically in pipes has been developed. Based on this method, a microprocessor-based measuring system was built to be installed and to operate in large-scale, industrial pneumatic transport installations. The measuring procedure is based on the detection of stochastic (stationary and ergodic) potential signals induced in two inductive ring probes mounted on a dielectric pipe, whose diameter is the same as that of a metal pipe through which charged solid particles flow, and which is inside a specially designed measuring head. The flow of charged particles induces stochastic electric signals in the probes; these signals are then converted into digital ones, processed, and cross-correlated in the microprocessor-based measuring system. The average flow velocity of solid particles traveling in a pipe can be determined in real time with high accuracy