Abstract: A cooling fan has a fan shroud with a fan wheel recess surrounded by a shroud ring and a fan wheel rotatably mounted in the fan wheel recess for conveying the air flow along a conveying direction from a shroud upper side to a shroud underside. The fan wheel has a central hub cup with radially orientated blades and an outer ring connecting the blades at the blade tip ends. A circumferential ring gap is formed between the outer ring and the shroud ring. A rib structure in the ring gap reduces swirl in a gap flow orientated against the conveying direction. A shroud ring section of the shroud ring extends axially beyond the outer ring on the shroud underside. The shroud ring section is orientated parallel or at an angle of inclination and radially inwards relative to the conveying direction.

Abstract: A process and apparatus for the selective recovery of solvents from solvent gas mixtures according to which the solvent gas mixture undergoes a sorption process, individual solvent gas fractions are fractionally desorbed from the sorption agent, condensed at staggered time intervals, measured to determine their composition, and collected separately.