Abstract: Sieve device for cleaning molten plastics in conjunction with a high-pressure press and consisting of a housing with a flow-through bore that constitutes part of the flow channel of the high-pressure press and of a plate or disk that can be displaced or rotated in the housing and that has several perforations or sieve chambers, at least one of which is always in the vicinity of the flow channel and at least one of which is always outside the housing, whereby either a sieve disk is always positioned inside the flow channel or sieve disks are positioned inside the perforations. At least one perforation is always inside the housing but outside the flow channel and can be evacuated before entering the flow channel by a suctioning-out pump or similar device. The sieve chambers are all separated from one another by curved webs, with the surface of one web equal to about 10% or less of the overall surface of one sieve chamber.