| 摘要 |
<p>The device has a helical curve-shaped slide surface (1) that guides from top to bottom, where the slide surface is arranged in an outer pipe (3). The slide surface forms a channel (2) that is radially limited in an outer side and radially opened in an inner side. The channel winds itself around a central free-space with diameter that is smaller than the diameter of a central column. A radially internal edge of the channel is bent downwards, where the pipe forms a radially outer boundary of the channel.</p> |
