Apparatus for separating steam from a mixture of steam and fibers is disclosed, comprising an elongated feeding compartment having an inlet and a feeding device for feeding a mixture through the inlet. The feeding device comprises a tubular section which is curved such that the mixture in the tubular section is separated under the influence of centrifugal forces in a heavy steam-less fraction of fibers in a outer layer and in a light fiber-free fraction of steam in a inner layer. The tubular section is arranged in such a way that a heavy fraction of fibers is fed through the inlet peripherally. The separated light fraction of steam is fed against the center of the compartment and removed through an outlet of the apparatus.