blade 3 in fig1 are designed with even steps 352 the graduated side edge 35 substantially increases its overall length and thus enhances the turbulence in the pulp suspension when the blade 3 rotates the contour shape of the blade 3 in fig1 has diverging side edges 35 in its front sector which then begin to deflect inwards approximately in the rearmost third of the surface 30 then run towards each other in two short branches to the rear at an angle and terminate at the rear edge 330 the blade 3 shown in fig1 has a dovetailed contour with a short front edge 310 fig1 18 and 19 show diagrams of blades 3 3 u2032 which can be connected in various ways by means of arms web plates 382 or supports 384 extending out from the rotor 300 the blades 3 3 u2032 are made of curved sheet metal particularly with a parallel outer surface 30 and inner surface 3001 according to fig1 and 18 a base section 383 is shaped onto the blades 3 3 u2032 the base section 383 in fig1 has an internal sleeve shaped recess 385 into which the prolongation 386 of the support 382 is inserted lateral projections 387 enclose the side limitations 388 of the recess 385 the projection 386 and the recess 385 are connected by a screw u2014 as intimated in the blade 3 3 u2032 design shown in fig1 the final sector of the base section 383 has a projection 389 which interacts with a projection 390 in the web plate 382 the projections 389 and 390 are screwed together u2014 as intimated at 384 according to fig1 the blade 3 3 u2032 can be screwed to.