by an arrow 42 so that a return of trash components 43 which have already been extracted into the fiber conveying path 14 is prevented in order that the light fly which clung to the heavier trash components 43 and traversed the air curtain in this manner cannot be sucked back into the fiber conveying path 14 even after it has been separated from the trash components 43 and so cannot enter the spinning rotor 3 and be bound in the thread 41 an air outlet aperture 24 is provided in a wall 221 following on the dividing edge 21 the air outlet aperture 24 is connected to a weak source of reduced pressure not shown which or the effect of which can be regulated as desired a powerful stream of air flows through the first aperture the air inlet aperture 220 as indicated by the triple arrow 223 this stream of air is produced by a source of excess pressure or as already mentioned by the suction action of the opening roller 10 and possibly the reduced pressure prevailing in the spinning rotor 3 or another spinning compartment as the single arrow 240 demonstrates the stream of air acting in the air outlet aperture 24 is considerably weaker than the stream of air flowing in through the air inlet aperture 220 the number of arrowheads and their relationship to one another has nothing to do with the relationship of the strengths of the streams.