Abstract: An apparatus for measuring the relative flow of pulverized coal in a plurality of pipes connected between a common pulverizer and respective burners comprises a plurality of electric charge sensors each disposed in a similar position on the plurality of pipes. The electric sensors sense an induced signal produced by charged pulverized coal particles. For unbiased flow, the induced signal is proportional to the amount of flow in each pipe as the charge properties of the particles from the pulverizer are the same for all the pipes. A circuit is connected to the sensors for obtaining a root means square value of the induced signal which in turn is compared to each induced signal respectively to obtain a measurement of the relative flow in each pipe. The induced signal can be integrated twice to improve the correlation between flow and charge amount since the integrated value is independent of radial position for the charges in the pipes.

Abstract: A measuring system (10) for measuring the flow of solids (w.sub.s) in a fluid stream is disclosed which utilizes only two differential pressure measurements (.DELTA.p.sub.1 ; .DELTA.p.sub.2) indicating the pressure drop across different points of a venturi (12). The fluid having the solids entrained therein is passed through the venturi (12) and pressure drop measurements are taken at points of the venturi (12). These pressure drop measuurements (.DELTA.p.sub.1 ; .DELTA.p.sub.2) are transmitted to a microprocessor (15) which calculates these measurements (.DELTA.p.sub.1 ; .DELTA.p.sub.2) according to a predetermined empirical formula to yield an output signal indicative of the flow of solids (w.sub.s) through the venturi (12).