PURPOSE: To restrain vibration generated on shutdown of a roller mill by installing an inert raw material feeder around a coal feeder to feed an inert raw material into a raw material feeding pipe.
CONSTITUTION: When gravel or limestone which is an inert raw material 19 is thrown in from an inert raw material feeder, pulverized coal is replaced with an inert raw material and a powder bed on a turntable 4 is the inert raw material 19, and the quantity thereof is larger than that of coal. A compressed powder bed 18 below pulverizing rollers 5 is thick and is coarse in grain size. When the pulverizing rollers 5 are rotated on the compressed powder bed 18, the rotation is stabilized and there is extremely little slippage in the form of lateral dislocation which is a start of the generation of self-excited vibration. Therefore, when a roller mill is stopped, in the raw material on the pulverizing part, the pulverized coal is replaced with the inert raw material 16, thereby the generation of self-exciting vibration when the roller mill is stopped is restrained.
MEGURI NOBUYASU
NISHIDA HIDEKAZU
SHOJI KAZUNORI
YUASA HIROSHI
