The authors have investigated the residence tune distribution of grains in a continuously operating two-cascade granulator disc by feeding (impulse disturbance) of marked (coloured) substances. They have determined the function between the virtual, the C-function based and the reduced average (mean) residence times, and the mixing coefficient as a function of disc rotation speed at two different axial angles, with particular regard to bed conditions on the outer disc. They have shown that in the second cascade the mixing of particles is considerably less intensive than on the inner disc. Furthermore they indicate that there is a significant difference in substance segregation and process application between the two cascades, which are separated by a deflector ring.