| 摘要 |
<p>An ornamental pond accessory comprises a moulded plastics shell in two sections 10,11, whose exterior resembles rock and forms a series of pools with waterfalls between them and whose hollow interior conceals a multi-stage filter which receives water pumped from the main pond, via distributor 22, 23, and feeds filtered water to the upper pool 14 over weir 13 to return to the pond. The filter comprises coarse and fine foam plastics sheets 18, 17 followed by a packing 16 of short cylinders designed to treat the water biologically. The treated water flows under wall 19 and up through zone 24 where it is irradiated by ultra-violet tube 25 to kill the algae. <IMAGE></p> |
