| 摘要 |
1390221 Filters MILLIPORE CORP 10 March 1972 [22 April 1972] 11218/72 Heading B1D Liquid is filtered by introducing it into a housing 29 wherein it passes through a cylindrical filter element 32 formed by spirally winding, on a core 23, a multi-layer web comprising two filter layers 7 and 8 which alternate with a spacer layer 5 and two spacer layers 6, 6a having a high percentage of void volume, some of the edges of adjacent layers being sealed by adhesive strips 50, 51, 52, 53 so that the liquid to be filtered, enters the top of the filter element through the spiral edges of spacer layers 6 and 6a, and passes sideways through the filter layers, the filtered liquid leaving the bottom of the filter element through the spiral edge of spacer layer 5. Liquid also passes into the filter element from space 31 through the outermost section of filter layer 8. The filtered liquid flows out of housing 29 through holes 37. The filter layer may comprise cellolose acetate or cellulose nitrate having an average pore size extending into the micrometer range as small as 0.025 micrometer. The filter layer may be laminated between two cloths woven from polyester fibres. Each spacer layer, which is preferably between 0.02 and 0.03 inches thick, may comprise a set of parallel plastics strands laid on and adhered to another set of parallel plastics strands, so that the sets of strands intersect at an angle. Epoxy-or polyurethane-based adhesives are particularly useful for providing the desired sealing between layers. The multi layer web is rolled on core 23 prior to curing the adhesive. A filter element can be produced by spirally winding a multi-layer web having more than two filter layers. Spacer layers could taper axially of the element from thicker open edges. |
