An improved apparatus for the centrifugal separation of at least two liquid phases and one solid sedimentary phase from a mixture, the said apparatus comprising:
- a rotating enclosure, first rotational means for rotating said enclosure, said rotating enclosure disposed around a nozzle supplying the mixture to be treated, said rotating enclosure being closed by a coronal base and coupled to said first rotation means for driving it in rotation, the said enclosure being integral with an angular partition therein which plunges into the mixture beyond the interface of the phases thereof, said partition separating a first chamber in said enclosure containing only the heavy phase from a second chamber in said enclosure containing the light phase "floating" on the heavy phase, said partition providing a peripheral annular passage for the transfer of the said heavy phase from the second chamber towards the first chamber, said first chamber being defined by a peripheral wall, said coronal base and said partition wall, the enclosure further presenting separate thresholds for the draining of the phases, a helical sediment conveyor within said enclosure, a second rotation means coupled to said conveyor via a plate which plunges into the mixture beyond the said interface, said plate separating the second chamber from a cavity in said enclosure with which said second chamber communicates on the periphery via a space near the conveyor for transferring the sediments through the heavy phase,
- a first centrifuge device housed in the first chamber and integral with said peripheral wall, said partition wall and said base thereof provided with surfaces extending inside the entire treated volume, across their circular movement, in order to transmit the rotation of the first driving means to the heavy phase according to an angular speed which is scrupulously constant throughout its whole mass and in every one of its points;
- a second centrifuge device housed in the second chamber and integral with said plate and with said conveyors, said second centrifuge device plunging at least into the light phase of the second chamber, said second centrifuge device extending along the said second chamber to arrive as close as possible to the partition wall, to the light phase draining threshold and to the annular passage of the heavy phase, and being provided with surfaces extending through the entire treated volume, across their circular movement, in order to transmit the rotation of the second driving means to at least the light phase, according to an angular speed which is scrupulously constant throughout its whole mass and in every one of its points, thus opposing the natural tendency of this type of flow with constant angular speed to degenerate into an irrotational vortex flow with tangential speed inversely proportional to the radius, which would destroy the stability of the interface and would lead to a re-mixing of the phases,
- a device for controlling the two means for driving the centrifuge devices for stabilizing and regulating the ratio of their respective rotation speeds.