| 摘要 |
<p>A sewage filtration device 101 comprises first 103 and second 105 perforated filters, the second downstream of the first, wherein the perforations 121 on the second 105 are smaller than those 113 on the first 103, i.e. the second filter has a finer mesh, or grid, than the first. Each filter may comprise a basket having side portions 109,11,117,119 and a perforated base 107,115. Sewage may enter the first basket 103 through one or two channels 123,125. In the latter case, the first basket 103 may have two compartments 103a,b. The filters 103,105 may comprise perforated plates 213,215, i.e. sieves, placed parallel to each other in an open-top channel 203. Elongate baskets 220,224,228,230,232, e.g. perforated, may extend across the top of the filter plates 213,215 and walls 205,207,209,211, e.g. perforated, of the channel 203. Also claimed is a sewer (Fig. 6) having a perforated reservoir into which sewage can flow if a portion of the sewer becomes blocked.</p> |
