Anordning for fjerning av urenheter

摘要

A mains water filter comprises sand and activated carbon to remove pesticides. The carbon may be mixed with sand or may form a layer 3 sandwiched between upper and lower layers 4, 5 of sand. The carbon may be loose or contained in textile bags, which may be internally divided and are placed on the lower sand layer. The filter forms a large rectangular bed with an overhead gantry carrying means for levelling the layers as they are applied and possibly for progressively removing sections of the upper layer as they clog, until the overall bed thickness is so reduced that the bed must be replaced.