| 摘要 |
<p>Aeration propeller consists of two flights each with cutting edges parallel to the propeller hug. A rear portion of reducing section extends from these. In each flight near the centre, on the cutting edge, are aeration holes connecting to the hollow shaft of the propeller. A hole for a securing pin through the shaft is also provided. The cutting surfaces from the widest portion of the blade and the rear portion extends round to the cutting edge of the other blade. In another embodiment, the cutting edges have a hemispherical depression in them. The circular edge of this depression reaches almost to the outer edge of the propeller. The propeller is esp. used in the biological prodn. of liq. manure.</p> |
