Patent ID: 6183647
Filing Date: 2001-02-06
Classification: B01D

Abstract:
A method for treating liquid, the method comprising:providing an apparatus comprising an essentially closed body, filtering means connected with the body for purifying liquid and comprising a filtering film defining a sandwich structure in which a secondary space for treated liquid is surrounded by a primary space for liquid to be treated, the filtering film comprising a particle track membrane or a track-etch membrane, the filtering film separating the treated liquid from the liquid to be treated, flow means connected with the body for introducing and removing liquid from the body, a support for supporting the filtering film, an intermediate storage space for storing filtered liquid downstream of the filtering means, and essentially self-powered purifying means for purifying the filtering means by cleaning the filtering film, whereby a primary side of the filtering film facing the primary space is flushed by a by-pass flow of the liquid to be treated passing the filtering film essentially tangentially; andpurifying the filtering means utilizing inverse flow by feeding treated liquid from the intermediate storage space through the filtering means in an opposite direction with respect to a filtration flow.