arranged at an obtuse angle with respect to comb 8 a strong impact of the textile fiber tufts which are accelerated by the injector nozzle 6 is realized in that a large grate area is thus made available by grate 27 fig5 shows an embodiment in which the grate 27 is disposed on the same side of the channel as the comb 8 due to the position of grate 27 above the comb 8 dust laden air and waste released by impact on the grate can be removed through the comb disposed directly therebelow the grate 27 is arranged at an acute angle with respect to comb 8 in the modified arrangement shown in fig6 the grate 27 is arranged at an obtuse angle with respect to comb 8 the angle between the grate 27 and the comb 8 is e g in fig3 u00b0 in fig4 u00b0 and in fig6 u00b0 fig7 shows a detail of an embodiment of apparatus in which combs 8d are fastened at successive locations along channel 3 and are laterally staggered so that successive combs are disposed on opposite inner walls of the channel system 3 on the side of the combs 8d facing away from the fiber tufts extraction devices 33a 33b and 33c respectively are provided a blower not shown.