| 摘要 |
951,404. Filters. PALL CORPORATION. Aug. 25, 1960 [Sept. 1, 1959], No. 29343/60. Heading BID. A filter assembly comprises in sequence a low bulk density high dirt capacity fibrous layer 32, a microporous membrane 28 of polymeric material, and a layer of paper or like fibrous material 31. The Figure shows a half section in an axial plane through a canister 27 closed at each end by a plate 25, and having perforations 23 each forming an inlet to a filter assembly. The assemblies are spaced by rings 35, 29, and the filtrate passes through the assemblies as shown by the arrows, and then through a wire mesh filter 19 as in Specification 830,908 into a central tube 17. The layer 32 may comprise fibres of quartz, glass, or a synthetic polymer, and the membrane 28 may comprise cellulose nitrate, polyvinyl chloride, cloth coated with cellulose nitrate or cellulose acetate, or nylon film cast from an alcohol water solution. The layer 31 may comprise paper, regenerated cellulose, cellulose polymers, polyvinyl chloride, nylon, "Dacron" (Registered Trade Mark), polyacrylonitrile,or polyvinylidene chloride. The spacers 29 may comprise thermoplastic or thermosetting material such as polystyrene, cellulose acetate butyrate, or phenolformaldehyde resin.
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