| 摘要 |
<p>A device for revolving a liquid has a hollow shaft for supplying gas to the liquid, and the free end of the shaft is immersed in the liquid where it carries a propeller for revolving the liquid. The propeller comprises at least one screw-shaped vane, and at least part of the vane's surface forms an acute angle with the longitudinal axis of the hollow shaft, as seen from the free end of the shaft, the vane extending along at least two thirds of the circumference of the shaft.</p> |
