Assembly comprising a vortex fluidic device for separating a mixture of a liquid phase and a relatively heavy, solid phase

In an assembly comprising a centrifugal separator having an inlet for a mixture of a liquid phase and a relatively heavy phase, the separator having a first outlet for a separated liquid phase fraction and a second outlet for a separated heavy phase fraction, the assembly also comprising a recirculation line, means for returning to the centrifugal separator through said line at least part of the heavy phase fraction discharged from said second outlet, and a discharge line for heavy phase fraction discharged from said second outlet but not returned to the separator, the improvement which comprises a vortex fluidic device in said discharge line for controlling the flow therethrough, said vortex device having an inlet and an outlet for discharging all the heavy phase fraction entering said last inlet, said vortex device being of the type in which the flow rate therethrough increases with increasing viscosity of the flowing material and vice versa, said assembly being operable through said vortex device to reduce the return rate of heavy phase fraction to the separator in response to an increase in the viscosity of the separated heavy phase fraction from said second outlet of the separator and vice versa.