Patent ID: 8852445

Claim:
A filtration apparatus for treating water or wastewater comprising: a vessel having a floor and walls; a cloth filter zone within said vessel including at least one cloth filter cassette positioned vertically therein; a backwash pump; and at least one backwash header positioned adjacent a main filter surface of said at least one cloth filter cassette, wherein said at least one backwash header comprises: an elongate tubular body having a length, a diameter, first and second ends, a longitudinal axis, and an exterior surface, the tubular body defining at least one internal cavity, the body comprising at least one suction slot to allow fluids and solids to enter the cavity, from outside of the exterior surface; and a hood structure comprising first and second substantially cylindrical rods extending substantially parallel to the slot and attached to the tubular body, and third and fourth substantially cylindrical rods extending substantially perpendicular to the slot and attached to the body, wherein said hood structure is attached to a portion of the exterior surface of the tubular body around and extending away from the suction slot to form a chamber defined by the hood structure and a portion of the exterior surface near the slot, the chamber comprising first and second sub-chambers on opposites sides of the slot, wherein the sub-chambers have sufficient volume to allow gradual straightening and relaxing of fibers of a filter material being cleaned by the backwash header, wherein the hood structure allows relatively clean fluid to pass through the filter material in a reverse direction upon application of a suction pressure in the internal cavity by said backwash pump, and allow the relatively clean fluid and solids previously adhered to the fibers to enter the chamber, then the slot and internal cavity while substantially preventing other relatively less clean fluids and solids from entering the chamber, slot and cavity.