Rotary drum filter

Abstract

The invention relates to a filter assembly for producing a paste-like filter cake and a substantially solids free filtrate or permeate. The filter assembly includes a substantially cylindrical member having an exterior foraminous surface, the cylindrical member being mounted on an elongate shaft for rotating the surface about an axis defined by the shaft. The exterior foraminous surface is covered by a microporous filter media. A stationary housing is positioned adjacent a portion of the exterior surface of the cylindrical member. The stationary housing includes a filter feed inlet and a sealing device and is spaced from the exterior surface a distance sufficient to enable cross flow relative to the filter media. Unique filter seal members promote retention of fluid to be filtered in a filtration area defined by the housing and cylindrical member. As the cylindrical member is rotated about the axis, a cake removal or membrane cleaning device removes filter cake from the filter media. The unique filter seal members enable use of a rotating cylindrical member containing the filter media. The unique design of the filtration device provides high solids production similar to a drum or belt filter without the use of filter aids and provides fine particle removal from a liquid similar to a membrane filter, however with substantially higher solids content than with a conventional membrane filter.