PURPOSE: To improve grinding efficiency and to eliminate the need for a disintegrator and to grind the brittle material such as cement clinker by alternately forming an annular recessed part and an annularly projecting part to a pair of respective rolls and forming the oblique faces to the respective annular recessed part and forming the oblique faces whose width is made narrower as reaching the tip parts to the respective annularly projecting parts.
CONSTITUTION: Both rolls 1, 2 are mutually rotated to the inside at the same velocity and cement clinkers 8, 9, 10 are supplied thereto. The clinker 8 introduced into the vicinity of the bottom part 6 of a recessed part 4 is compressed in the direction A7 by the tip part 7 and ground. The clinker 8 receives shearing force by difference of the circumferential speed together therewith and becomes fine powder. Further in this case, since the oblique face 11 of a projecting part 5 is tilted, compression force is made slightly weaker than the tip part 7. Therefor this clinker is partially moved in the direction A8. Deviation due to shearing is added to this partial movement. The ground brittle material is discharged from this roll device as fine powder without becoming a flake shape. Thereby the brittle material is pulverized at high efficiency.
MIYABE YOSHIHIKO
OBANA HIROSHI
