Pressure drop and separation efficiency in a flooded hydrocyclone

The pressure drop and separation efficiency were measured of a hydrocyclone operating under flooded underflow or no air-core conditions. The solids were glass spheres with a geometric number average diameter of 13 μm and a geometric standard deviation of 1.69. Water was the fluid. Other fixed variables included the solids feed concentration of 2265 mg/L, the glass hydrocarbon configuration following the optimal Rietema recommendations and the temperature. The variables were feed flowrate 0.44 to 0.63 L.s¹ and volume split of 2.4:1 to 6.1:1; a factorial design was used. The pressure drop, ΔP_s, was 4 to 7 times larger than that expected for air core operation and was correlated in terms of the capacity ratio Q/(ΔP_s)^0.47. The pressure drop was relatively independent of volume split. The separation efficiency was a much stronger function of volume split than of feed flowrate. The D_p(50) diameter at a feed flowrate of 0.63 L.s^?1 lies between 4.3 to 9.2 μm; of the seven correlations available for predicting D_p(50), the approach of Rietema (1961) gives the best results. The experimentally measured reduced efficiency was less sharp than that reported by Yoshioka and Hotta (1955) and by the theory of Uematu et al. (1962).