Decanter centrifuges are used in separation of the solid-liquid or solid-liquid-liquid suspensions. The machine is consist of a solid cylindrical bowl rotating at high speed, a scroll rotating in the same axis with a slightly different speed, gear box adjusting the speed difference and the body which carries all the rotating elements. The product is fed along the centre line to a fixed distribution room within the bowl and then accelerated into the bowl by centrifugal force through the feeding point. This centrifugal force then causes the suspended solids(the cake) to settle and accumulate at the bowl wall. The cake is discharged by scroll from the conical part meanwhile clarified solid and water or only liquid flows back along the bowl and is discharged through the cylindrical end of the bowl by plates which can adjust the level of liquids.