Performance characteristics within a modified hydrocyclone

It has been reported by Xu et al (1990) that the suppression of the axial air core within a hydrocyclone could improve process performance. This work presents the results of an extensive series of experiments to test this postulation by measuring the classification and separation efficiency of conventional hydrocyclones compared with modified hydrocyclones, in which the air core is replaced by an axial steel rod insert. The influence of rods of various dimensions on a number of design parameters (e.g. pressure drop, volumetric flowrate and cut size) is reported.
The insertion of a 3 mm diameter 377 mm long rod into the hydrocyclone, 8 mm vortex finder diameter and 5 mm spigot diameter, to remove the central air core resulted in a maximum increase of 44% in the volumetric throughput for the same pressure drop. But in all cases the sharpness of classification, fineness of cut-size and overall separation efficiency was inferior.
Since the insertion of a rod into the hydrocyclone does not appear to improve the separation efficiency other approaches, e.g. hydrocyclone networks, must be employed.