The press screw separator (1) has a housing (2) and a cylindrical sieve (3) arranged in the housing. A longitudinal direction and a circumferential direction are defined at the cylindrical sieve. The sieve is rotated around the longitudinal direction. A screw is arranged inside the sieve for grouting the slurry, where the screw is rotated around the longitudinal direction. A holding element is arranged in the housing. An actuator is provided for moving the holding element between a locking position and a freewheeling position. An independent claim is included for a method for operating a press screw separator.
