Electrostatic, inductive ring probe bandwidth

Electrostatic, inductive, non-intrusive probes are employed for measuring the electric charge as well as the mass flow rate, volume loading, and mean flow velocity of solid particles especially while travelling through pipes of pneumatic transport or in ambient air when a flux of those particles forms a rather compact column-like jet of a nearly constant cross sectional area. The bandwidth of such measuring devices is a very important factor which should be determined carefully, or even planned in advance, before designing the probe itself intended for the use under well defined conditions. In the paper the bandwidth of the inductive ring probes is discussed. To find the probe bandwidth the derivation of a general formula is presented along with the accepted assumptions and an original way of formulation and consideration of that problem. The general formula obtained is an inductive ring probe frequency response function and permits the bandwidth of any inductive, non-intrusive probe, sensor, transducer, etc, to be easily determined for given mean flow velocities of particles and probe widths.