A conveyor screw for conveyance of high viscose masses and an apparatus with such a conveyor screw, preferably for production of an ice cream. Said crew having a plurality of screw flights, where at least two screw flights extend from an inlet end part of the conveyor screw and wherein the outer edges of the two screw flights extend in different radial distance from longitudinal axis. Whereby the radially shorter screw flight assists with the conveyance of a part of the mass without affecting the whole mass and especially without affecting the ice layer, which by use of the conveyor screw in a through-flow freezer is created on the inner wall of the freezing cylinder. Cooling the mass to a temperature of -15.degree. C. or lower as preparation for extrusion of the mass for formation.