摘要 |
PCT No. PCT/GB93/01379 Sec. 371 Date May 22, 1995 Sec. 102(e) Date May 22, 1995 PCT Filed Jun. 30, 1993 PCT Pub. No. WO94/01207 PCT Pub. Date Jan. 20, 1994An apparatus for producing a high solids content aqueous dispersion from a low solids content aqueous dispersion, for example waste water containing dilute emulsion paint. At least two membranes are arranged in series, a first membrane being of hollow fibre structure with a bore diameter greater than 1 mm and a pore size of less than 3,000 Kilodaltons molecular weight cut off, and a second tubular membrane being of bore diameter less than 50 mm and pore size of less than 3,000 Kilodaltons molecular weight cut off. The low solids content dispersion is passed across a face of the first membrane at a cross flow velocity of from 0.5 to 5.0 meters per second, a differential pressure being applied to force liquid through the membrane. The resultant retentate has an intermediate solids content and is passed across a face of the tubular membrane at a cross flow velocity of from 0.5 to 5.0 meters per second. A differential pressure is applied across the tubular membrane to force liquid therethrough. The resultant retentate is of high solids content, for example greater than 40% solids content given a starting dispersion of from up to 5% solids content.
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