ABSTRACT
The electric current generated by particle impact is proportional to the powder flow rate. The weighing method is the most reliable and accurate for measurement of the powder flow rate in a bulk solids flow. The belt scale is, however, more suitable than the hopper scale for the continuous feeding of powder, where the flow rate is obtained as a product of the weight of powder on a belt of unit length and the belt speed. When the flow rate is controlled to feed a constant powder mass, the belt scale is called a constant-feed weigher. The electric currents generated by particle impact can be applied to the measurement of the powder flow rate in gas–solid mixture flow. However, the concentration should be rather small, because the relation between the current and flow rate becomes nonlinear for high concentrations. The powder flow rate is obtainable as the product of concentration and velocity.
