An entrainment device for a centrifugal rotor, which is rotatable about a
central rotational axis, having a number of entrainment members arranged
in said space for entrainment of entering liquid in the rotation of the
centrifugal rotor. The entrainment device comprises a first component,
which surrounds the rotational axis and has at least one first
projection, which has a radial extension, and a second component, which
surrounds the rotational axis and has at least a second projection, which
also has a radial extension. The second component is axially insertable
in said central space to a position, in which said second projection is
present adjacent to said first projection . When the entrainment devices
are in place in the central space, a locking member is applicable in
releasable engagement with said projection so that the second component
is prevented from moving axially relative the first component.