| 摘要 |
<p>The specification discloses an improvement in rotary drum screens for the filtration of liquids which comprises (a) a drum having a central horizontal axis and a radially outer surface, (b) a plurality of microscreen grids mounted on the radially outer surface of the drum, each of the microscreen grids comprising a microscreen which is divided into a large number of small cells by walls which extend radially with respect to the drum, (c) means for introducing liquid to be filtered into the interior of the drum, (d) means for rotating the drum about its central axis, (e) a backwash header mounted outside the radially outer surface of the drum, and (f) a backwash receiving trough mounted within the drum for collecting filtrate accumulated on the screen. The liquid to be filtered is introduced into the drum at one end thereof, and the drum is supported so that it is partially submerged in the filtered liquid. The improvement resides in the fact that at least some of the walls which divide the microscreen grids into cells are at least generally parallel to the central axis of the drum and extend radially outwardly from the microscreen a distance sufficient so that, during use of the rotary drum screen to filter a given liquid, the said walls retain an amount of the liquid which just has time to drain through the microscreen between the time each cell emerges from the filtered liquid and the time it arrives underneath the backwash header.</p> |
