Mitsubishi Jukogyo Kabushiki Kaisha

Hirohisa Yoshida

Tsugio Yamamoto

Masaaki Kinoshita

Katsuyuki Ueda

Hidenori Sakamoto

Yutaka Iida

Takeshi Kunimoto

Shuichi Sakota

The present invention provides a rotary classifier for a roller mill, in which a rotating vane is formed so that the vane width at the upper part of the rotating vane is larger than that at the lower part.

Rotary classifier for a roller mill

A horizontal mill for ultra-fine pulverization which has enhanced pulverization characteristics and reduced power consumption while suppressing damage or wear of pulverizing media. The pulverizing media (balls) are provided in a pulverizing chamber defined by a space between an inner cylinder and an outer cylinder which are rotated relative to each other. Large diameter pulverizing media are used and the rotational speed is kept at a low level, which is opposite to the conventional theory of using small diameter media and high rotational speeds. Since the rotational speed is low, the corresponding wear of the pulverizing media is reduced. The degradation in pulverizing performance due to the low rotational speed may be recovered by using large diameter pulverizing media. Also, the dimensional ratio between the inner and outer cylinders, the interval between the inner and outer sleeves, and the axial interval between agitating vanes are suitably selected to enhance the mill performance.

Pulverizing method and horizontal mill

Raw coal is caused to fall through a coal feed pipe and onto a table so as to be pulverized by a roll. Fine coal particles and coarse coal particles resulting from pulverization are moved upward between an auxiliary classifier cone and a mill casing by hot air supplied from below the mill casing. The hot air (upward stream) carrying the fine coal particles and the coarse coal particles moves across a space of triangular cross section formed between the inverted conical body of the auxiliary classifier cone and the side wall of the mill casing and is forced through blowoff openings defined between deflector plates so as to flow as a lateral rotative stream toward a rotary classifier. Upon impinging the downward-inclined rotating vanes of the rotary classifier, the coarse coal particles are sprung back toward a lower portion of the auxiliary classifier cone and are separated from the fine coal particles. The fine coal particles separated from the coarse coal particles are ejected out of the roller mill together with the upward air stream through a pulverized-coal eject pipe. Coarse coal particles sprung back toward the lower portion of the auxiliary classifier cone move along the inner surface of the auxiliary classifier cone and fall onto the table so that they are re-pulverized by the roll.

Roller mill

Growing community of inventors

Nagasaki, Japan

Hirohisa Yoshida