is a stationary separator that is porous to air flow there through but impervious to desirable fiber flow there through rotating within the cylindrical housing is an revolving air separator 17 which is pervious to both fiber and foreign matter as may be seen in fig1 terminal wall portion 14 of duct 11 converges toward revolving air separator 17 near cleaning cylinder 12 such that fiber tufts carried by the conveying air stream are directed substantially on to the teeth 13 of cleaning cylinder 12 while the direction of the conveying air flow is gradually changed toward the cylindrical housing comprising perforated surface 16 again as may be seen in fig1 revolving separator 17 includes a plurality of circumferentially spaced outer surfaces 18 such that the spaces between spaced outer surfaces 18 are sufficient to allow the conveying air to pass between the spaced surfaces 18 as air duct 11 converges toward the spaced surfaces 18 without abruptly increasing the conveying air velocity outer surfaces 18 pass proximal to the revolving cleaning cylinder 12 and semi cylindrical stationary surface 16 in one embodiment outer surfaces 18 are defined by circumferentially spaced apart flexible belt like strips running generally parallel to the axis of rotation of air separator 17 and generally radial to the axis of rotation the strips are flexible radially and may be made of soft material to resist damage to the cleaning cylinder 12 or semi cylindrical stationary surface 16 in another embodiment spaced outer surfaces 18 are defined by circumferentially spaced apart brush strips running generally parallel to the axis of rotation with the bristles facing outward generally radial to the axis of rotation of the air separator 17 suitable hub plates 22 hold the hubs 25 of the strips 18 in place forming an.