Filter candle with insert in bore - which narrows under pressure of incoming suspension minimising filtrate loss during candle replacement

摘要

Pressurised suspension enters from an axial base inlet in a rigid cylindrical casing, to be filtered on passing radially inwards from a surrounding gap through an annular filter candle which is sintered, folded or wound from polypropylene, "terylene", polyamide, cotton, glass fibre or steel filaments. The central bore in the filter candle holds a flexible compressible insert which under pressure of incoming suspension contracts, permitting filtrate flow towards an outlet aperture in the screwed on casing cap. When pressure is relaxed, esp. during replacement of a filter candle, the insert resumes its original size. The insert may be a foil bag filled with flexible foam, or with gas pressurised to lower value than the incoming suspension. ADVANTAGE - Loss of filtrate during change-over is minimised by an easily made insert.