Abstract: In a method of rapidly lowering the rotary speed of a rotating rotor body in a centrifugal separator the lowering of the rotary speed is initiated, when a disturbing unbalance or vibrations have occurred. A space between the rotor body and a stationary casing which surrounds the rotor body is supplied with foam or with an aerosol of a liquid in a gas, when unbalance or vibrations over a certain level have occurred. The rotor body is retarded by the friction, which is obtained between the rotor body, the foam or aerosol and the casing. In an arrangement to lower the rotary speed of a rotating rotor body in a centrifugal separator the lowering is initiated when a disturbing unbalance or disturbing vibrations has occurred. At a certain unbalance or certain vibration level, a foam generating device or a device that creates an aerosol for the purpose of filling a space between the rotor body and a casing which surrounds the same with foam or aerosol is activated.

Abstract: In a method of rapidly lowering the rotary speed of a rotating rotor body in a centrifugal separator the lowering of the rotary speed is initiated, when a disturbing unbalance or vibrations have occurred. A space between the rotor body and a stationary casing which surrounds the rotor body is supplied with foam or with an aerosol of a liquid in a gas, when unbalance or vibrations over a certain level have occurred. The rotor body is retarded by the friction, which is obtained between the rotor body, the foam or aerosol and the casing. In an arrangement to lower the rotary speed of a rotating rotor body in a centrifugal separator the lowering is initiated when a disturbing unbalance or disturbing vibrations has occurred. Means are arranged at a certain unbalance or certain vibration level to activate a foam generating device or a device that creates an aerosol for the purpose of filling a space between the rotor body and a casing which surrounds the same with foam or aerosol.

Abstract: In a centrifugal rotor (1) for separation of a substance from a liquid mixture supplied to the centrifugal rotor there is delimited a separation chamber (7) having peripheral outlets (30). The centrifugal rotor includes an outlet device (20-28) for intermittent opening and closing of the outlets (30) during rotation of the centrifugal rotor. An actuation device (31-40) may cause the outlet device (20-28) to keep the outlets (30) open to a varying extent and/or during a varying time, and a control device (43) is adapted to control the actuation device (31-40) in response to a sensed value of the amount of mixture supplied to the rotor, such that a predetermined amount of separated substance (29) having collected in the separation chamber (7) is discharged through the outlets (30) each time these are opened and closed.