Abstract: At a centrifugal separator (21), where separated sediment is thrown out in jets (26) from the rotor (22) of the separator through a determined number of nozzles (1, 2, 3) a sensing means (28) is arranged to be influenced by the respective jet and give off a signal (U), which is a measure of a quantity, e.g. the flow, of the medium of the jet, which signals (U) are given off to an apparatus (38), which is arranged to record the signals (U) and in its turn give off a signal (39, 39A, 39B, 39C), if said quantity of the medium in one or more jets is changed, e.g. if the flow through a nozzle ceases by the nozzle having been blocked or if the flow through a nozzle has increased by the nozzle having been eroded.

Abstract: A centrifuge rotor has a first part axially displaceable into and from abutment against a second part of the rotor during operation of the centrifuge, the rotor also having peripheral outlet openings for separated sludge which are formed by and between said rotor parts. One of the rotor parts has grooves forming said outlet openings when the two parts abut each other, said parts forming a continuous opening around the periphery of the rotor when the two parts are separated from each other.