| 摘要 |
PROBLEM TO BE SOLVED: To provide a reverse flow preventing device 12 provided in a rotary cylinder 1 without fixing the reverse flow preventing device 12 in a rear part of a fixed base 13. SOLUTION: The reverse flow preventing device 12 is united with the inside of the rotary cylinder 1 to rotate the device in the same way as the rotary cylinder. It has the following structure, namely, a truncated conical cylinder 2 is provided at the center of the rotary cylinder 1 having a transverse cylindrical shape, conical large diameter 3 and conical small diameter 4 are provided in a front part and a rear part of the truncated conical cylinder 2, respectively, a front disc 5 is provided between the conical large diameter 3 and the rotary cylinder 1, the conical large diameter 3 is opened, the conical small diameter 4 is closed by a preventing wall 6, a plurality of spiral blades 7 are provided between length in the front and rear of the truncated conical cylinder 2 and the rotary cylinder 1, and a plurality of front part cut-out holes 8 are provided in a front part of the truncated conical cylinder 2. COPYRIGHT: (C)2006,JPO&NCIPI
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