publication_number US 4531262 A abstract textile fibers are blended by introducing them in a pre blender performing an at least two fold doubling of the textile fibers in the pre blender pneumatically introducing the textile fibers in a principal blender from the pre blender performing a multiple doubling of the textile fibers in the principal blender and removing the textile fibers from said principal blender application_number US 44352682 A description turning to fig1 there is shown a principal blender 1 which may be a conventional multi mixer mpm model the principal blender 1 has six serially arranged hoppers 2 3 4 5 6 and 7 communicating with an overhead duct 8 through which fibers are conveyed by an airstream in a direction indicated by the arrow a the hopper walls 9 have air outlet openings 10 in the zone of their upper portions each of the hoppers 2 through 7 may be closed at the top by means of respective pivotal closures 11 which in their open position as shown for the closure 11 of the hopper 2 close the downstream side of the duct 8 in the zone of the lower end of each of the hoppers 2 through 7 a delivery roller pair 12 and an opening roller 13 are arranged underneath the hoppers 2 through 7 a common blending channel 14 is arranged from which the fiber tufts deposited therein are conveyed towards a suction funnel 15 which is coupled to a condenser not shown the fiber material is by means of a fiber driving impeller 15 drawn through a pipe conduit 16.