| 摘要 |
PURPOSE:To reduce the fluctuations of gap owing to temperature differences of the inside and out of the drum by forming openings for acceleration the flow of air to the inside and out of the drum to the flange parts. CONSTITUTION:Openings 15a, 15b which communicate the inside and outside of the drum and introduce external air to the inside of the drum are formed to the end face of the drum. The shapes of the openings 15a, 15b may be any of circular, rectangular, trapezoidal, etc. and are diagonally formed so as to intersect obliquely to the central axis of the drum to permit easy entrance of the air of the drum outside into the drum through the opening 15a. As the inside and out of the drum are communicated in this way, circulation takes place right after the starting and even if heat acts upon the drum from each contact part, all parts of the drum are maintained at an approximately equal temperature by the air circulation. Hence, the deformations of the drum outside surface owing to the temperature differences of the inside and out of the drum may be reduced and gap fluctuations reduced. |
