Although N. Brook has mentioned in his research on flow measurements of participate solid-liquid mixtures that the flow in vertical pipes should be modified by slip between the particles and the water, the slip effect has not been taken into account.
In this paper, theoretical and experimental methods are presented for measuring the flow rate of particulate solids in solid-liquid mixtures in view of the slip velocity by using vertical connected pipes of two different diameters, it is shown that the slip velocity can be calculated by measuring the difference between the transport concentrations of solids in two pipes resulted from the difference in the particle velocities in each pipe. The velocity of liquid is measured by an electro-magnetic flow meter and the flow rate of particulate solids is calculated theoretically. Reasonable coincidence between theories and experiments are reported.