Almost all manufacturers of blowroom machinery now offer dust-removing machines or equipment in addition to opening and cleaning machines. However, dust removal is not an easy operation, since the dust particles are completely enclosed within the flocks and hence are held back during suction (because the surrounding fibers act as a filter). Since, as shown by Mandl , it is mainly the suction units that remove dust (in this example 64%), dust removal will be more intensive the smaller the tufts.
It follows that dust elimination takes place at all stages of the spinning process. Fig. 5 shows Mandl’s figures for the various machines.