Mixer for viscous materials, for example for filter cake, pulp or the like

Claim 1

A mixer for low liquid content material, including filter cake, pulp, and the like, in which said material is initially comminuted and ground and thereafter mixed and thickened to render it pumpable, said mixer comprising: a housing having a tubular portion (1) including an inlet at one end through which the material is received in the mixer; a rotatable shaft (9) extending into said housing; a first knife impeller (11) mounted in said tubular housing portion on said shaft for rotation therewith in a first plane (I); a second, plural vane knife impeller (27) mounted on said shaft for rotation therewith in a second plane (III) spaced below said first plane; first and second sets of stationary knives (33-35; 40-42) mounted on said tubular housing portion for coaction with said impellers, said first knife set being positioned in a plane (II) between said impellers, said second knife set being positioned in a plane (IV) below said second impeller, said impellers and stationary knives being mounted for mutual coaction to grind and comminute the material; said housing having a frusto-conical portion mounted at the other end of said tubular portion and converging in the flow direction to an outlet through which the treated material is discharged; a plurality of circumferentially spaced guide ribs (53) mounted in said conical housing portion; a third set of stationary knives (63, 64) mounted in said conical housing portion; guide paddles (54, 55) mounted in said conical housing portion below said third set of knives in the outlet of said conical housing portion; helical ribbon segments (48, 49) mounted in said conical housing portion on said shaft for rotation therewith above said third set of knives; and thrust paddles (57-59, 70-72) mounted on said shaft above and below said third set of knives, said elements contained in said frusto-conical housing portion being mutually operatively associated to mix and thicken said material.