GB1353071A - Process and apparatus for the continuous filtration of liquids - Google Patents

Abstract

1353071 Moving bed filter TATABANYAI SZENBANYAK 20 May 1971 [25 May 1970] 15938/71 Heading B1D Water is filtered by flowing horizontally through a sand bed 5 confined between perforate or shuttered walls 3, 6, bed 5 being constrained by an insert 12 located between tapering walls 12a, 12b to flow downwards with substantially uniform velocity across its crosssection, the downward velocity of any particle being with 10% of the average. Sand drawn through outlet 15 is regenerated chemically or by centrifuging, settling or vibratory screening to remove contaminants, and recirculated to inlet 11. Prefiltering zone 16 enables the bed to reform before it is used for filtering again. Some water may be bled off with the sand through outlet 15 but is recycled, and insert 12 may include water injection passages to assist in sand movement. In Fig. 1 the water flows inwards through an annular bed, and in Fig. 2 (not shown) the flow is outwards, enabling zone 13 to act as a preliminary settling zone. Also in Fig. 2 imperfectly filtered water passing through the upper part of the bed is recycled by a venturi or pump line (18). Figs. 3, 4 (not shown) illustrate a single flat sided bed, and Figs. 5, 6 (not shown) illustrate a plurality of such beds operating in parallel with common inlet/outlet spaces. The housings, shutters and pipes may be of glass fibre-reinforced P.V.C. or polyester. Insert(s) may be of locenge crosssection and adjustable to vary the sand flow rate.