| 摘要 |
<p>Method comprises passing it upwards through a bed of granular filtration agent (I). (I) moves in counter-current to the liquid being filtered and is then transported away from the bed and fed in counter-current to wash liquid (II) in a washing zone after which it is fed back to the top of the bed. - A layer of filtrate is maintained above the bed and this is fed as washing liquid to the washing zone. Pref. the relative velocity of the (I) and (II) is increased or decreased momentarily once or more during washing, or it is decreased and the increased momentarily. - The arrangement is compact gives almost the same capacity as a filtration installation without separate washer and gives improved washing of (I). USAB- US4126546 A A suspension or emulsion is filtered by causing it to flow upwards through a zone of filter medium of particle size forming a filter bed while the filter medium concurrently flows in a downward direction through the filter bed zone. Dirty filter medium at the bottom of the filter bed zone is transported to a wash device located above the filter bed zone and is washed as the dirty medium passes downward along a washpath in the wash device in counter current flow to wash liquid which passes upward through the wash device, where-after the washed medium is returned to the top of the filter bed zone. A zone of filtrated liquid phase is maintained above the filter bed, and a portion of the filtrated liq. phase is supplied to the wash device as the wash liq. (Claim 1-10 have been deemed patentable). ((Dwg.0/1))</p> |
