Solids excluding surface skimmer

Claim 1

A skimmer for decanting treated liquid from a sewage settling basin, comprising: an elongate weir which comprises an input weir lip means over which liquid from the basin may flow; conduit means in liquid communication with the weir for removing liquid from the basin; means for raising and lowering the weir relative to the liquid level in the basin; extended end plates on the ends of the weir; an elongate floatable scum and solids barrier means disposed generally parallel to the weir, said barrier means comprising an elongate floatable structure and an elongate surface scum intersector secured along the length of the barrier means and extending downwardly therefrom, said barrier means being constructed and arranged to seal against the weir when the skimmer is raised above the liquid in the basin and to intersect surface scum cleanly upon entry of the skimmer into such liquid in the basin to prevent entry of scum into the weir when, in use, the skimmer enters the liquid; means forming a moveable solids barrier seal between the respective ends of the solids barrier means and the respective end plates; and linkage means mounting the solids barrier means to said weir, said linkage means being constructed and arranged to allow for movement of said solids barrier means away from the weir during lowering of the weir; the weir, end plates, seal means and barrier means being so constructed and arranged to permit the barrier means to move away from the weir as the liquid level in said basin lowers to thereby define a solids-free decantation zone of increasing size between said weir and said barrier means during lowering of the skimmer during decantation.