The invention relates to a decanter centrifuge with a rotating bowl (1) provided with at least one solids discharge port (11) and at least one clarified liquid discharge port (15) and a screw conveyor (2) disposed coaxially within said rotating bowl rotated in the same direction with a differential rotational speed, where a feed suspension to be separated is introduced into a ring shaped space formed between said rotating bowl (1) and said screw conveyor (2) through a central feed pipe fixed to the end of the screw conveyor and supported in at least one bearing and can be separated by centrifugal force into a solid and a liquid phase so that said solid phase is discharged from said solid discharge port and said liquid phase is discharged from said clarified liquid discharging apparatus. According to the present invention it is characterized by a liquid phase conduit (4) arranged in the hollow shaft of the rotating bowl (1) guiding the liquid phase outside of the bearings (16, 18), a liquid phase discharge valve (14) provided outside the bearing on the side facing away from the bowl (1) and screw (2) and a sealing (6) at the end of the feed pipe (10) surrounded by the liquid phase conduit. So it is possible to pressurize the system and to use the pressure from the feed pump to support the cake transport in the solids transporting part of the bowl, thereby eliminating the need for variable speed conveyor control and equipment.

A solid bowl screw centrifuge has a feed pipe with a diameter initially increasing in the axial direction towards in the direction of flow to form a first feed pipe section in which a centrifugal pre-separation of a part of the solid phase from the suspension occurs. A first portion with a higher solids content compared to the suspension is introduced by a first outlet into the centrifugal chamber in the radial direction. A second feed pipe section adjoins the first feed pipe section axially in the direction of flow, through which the remaining second portion of the suspension that is not discharged through the first outlet and has a lower solids content compared with the suspension is guided further axially through the feed pipe. The remaining second portion of the suspension is introduced into the centrifugal chamber in the radial direction via a second outlet.