Abstract: The invention relates to an opening cylinder (2) of an open-end spinning device as well as a fiber sliver opening apparatus with such an opening cylinder. In at least one lateral area (6) of the opening cylinder (2) a sealing surface for an air gap seal (12) is formed. According to the invention the opening cylinder (2) has an air passage (14) in at least the one lateral area (6), the output side of the air passage lying within the sealing surface or adjoining the sealing surface directly and the input side of which being at a shorter distance from the rotational axis of the opening cylinder (3) than the output side. During the operation of the fiber sliver opening apparatus, air is conveyed through the passages (14) to the air gap (12) of the air gap seal arrangement or conveyed past it, so that the entry of air and pollutants into the air gap (12) is counteracted.

Abstract: Apparatus for the production of a corrugated cardboard having a cover-lining on at least one side, with an upper grooved roll and a lower grooved roll which have outwardly open annular grooves in distribution over their length, to which a suction source is connected through nozzles held by carriers, of which nozzles two in each case are arranged opposite to one another in the region of the paper web entry and exit of the lower grooved roll, fitting into an annular groove, characterized in that each annular groove (12) has a width substantially less than its depth, in that each nozzle (13, 13') which fittingly fills the annular groove possesses a pressed-flat pipe end (14, 14') and in that at least the outer nozzles of the nozzles arranged in a row are connectable additionally to an air blast source (32).