Method for the filtration of a suspension or emulsion

Claim 1

In a method for filtering wherein a suspension or emulsion to be filtered is supplied to a zone of particle filter medium forming a filter bed, the suspension being filtered flows, during the filtration thereof, in an upward direction through the filter bed and is discharged from the filter bed as filtrated liquid phase, and wherein the filter medium during the filtration flows in a downward direction through the filter bed in counter-current to the suspension past the inflow of the suspension and thereafter is transported separated from the filter bed to a wash path for washing the dirty filter medium during flow along the wash path in counter-current to a wash liquid, whereupon the washed filter medium is returned to the filter bed zone to its top surface, the improvement wherein at least a part of the filtrated liquid phase which is discharged from the filter bed zone is maintained above this zone as a zone of filtrated liquid phase in direct contact with the filter bed zone, said separated transport of the dirty filter medium takes place upwards through the filter bed zone, and said counter-current washing of the dirty filter medium along the wash path takes place during flow of the dirty filter medium in counter-current to a portion of said filtrated liquid phase utilized as wash liquid, said portion of said filtrated liquid phase being supplied to the wash path from said zone of filtrated liquid phase.