Abstract: A centrifuge bowl of the type having a base onto which the intermixed particulate materials in slurry form is fed for passing over the peripheral wall of the bowl includes a plurality of annular recesses at axially spaced positions on the peripheral wall with each recess having a plurality of openings at the base of the recess communicating with the jacket on the outside of the peripheral wall. Water is supplied through a channel in the support shaft of the bowl via a rotary union on the shaft which is arranged to cause a fluctuation in the flow rate of water passing to the jacket.