| 摘要 |
1499347 Purifying water GELMAN INSTRUMENT CO 7 Oct 1975 [21 Oct 1974] 41105/75 Heading ClC [Also in Divisions Bl and F2] A domestic water filter adapted to be screwed to a tap outlet 6 comprises a two-part housing 32, 34 enclosing a replaceable cartridge 38 (Figs. 5, 6, not shown) which consists of an annular shell 40 open at the top and enclosing at least one layer 50 of woven or felted cotton or polyester fibres incorporating activated charcoal particles of 5-50 microns diameter, an intermediate layer (54) of pore size smaller than the charcoal particles (e.g. 1-10 microns) and a downstream layer (52) of pore size 0À2 to 0À5 microns which stops bacteria. Layer (52) is a unitary film of copolymer of acrylonitrile and polyvinyl chloride, possibly reinforced by a nylon fibre web embedded therein. Layer (54) may be similar to layer (52) or may be woven or felted polyester. Layers 50, (54) and (52) are shown sandwiched between layers (62) and (56), both of woven or felted natural or polyester fibre, 100-300 microns thick and with pore size greater than 10 microns. Layers (52) and (54) may be cemented to shell 40. Layers (52) and (54) are respectively 100-250 microns and 200-800 microns thick, and layers 50 total 0À1 to 0À2 inches in thickness. The floor 42 of shell 40 comprises an integral grid whose bars are of triangular cross-section with apices directed upwards, and downward projections (66) hold shell 40 off the lower housing part 34. Housing parts 32, 34 may screw together as shown or make a bayonet coupling and include radial grooves 20, 18 which carry water to and from the cartridge 38 when by-pass valve 28 is closed. When the valve is open as shown water flows from tap 6 to aerator 10 directly through central passage 12, 14 and is not filtered. The valve comprises a rubber washer 28 moved axially towards seat 30 by rotating cup-like member 19,22 which screws on to the housing. Member 19, 22 has apertures 23 by which water leaves the housing. |
