Floating skimmer for cleaning the surface of a body of liquid, method and apparatus

A floating skimmer for skimming the surface of a body of liquid surrounding the skimmer while providing a self-compensating positioning of a weir for maintaining efficient skimming flow over the weir during varying conditions of operation, said skimmer comprising,

• an outer body having an inner, generally centrally disposed cavity,
• first flotation means in the outer body for regulating the level of flotation of the skimmer at rest before start-up of skimming operation,
• an opening in one peripheral part of the outer body for admitting a flow of liquid into the central cavity,
• drain means associated with the central cavity for draining liquid from the cavity and for conducting the drained liquid effluent away from the cavity during skimming operation,
• a movable weir extending across the width of said opening for regulating the quantity and velocity of liquid flow through the opening and into the central cavity,
• weir-positioning means for adjusting the height of the weir with respect to the surface of the body of liquid surrounding the skimmer to cause a cascade of liquid in a waterfall off the upper edge of the weir and a skimming of the surface of the liquid by the cascade action,
• said weir-positioning means including second flotation means on the underside of the weir for supporting the weir above the level of the liquid in the cavity during skimming operation,
• said second flotation means having sufficient excess buoyancy to keep an upper portion of the flotation means and the weir always high enough above the level of the liquid in the central cavity to prevent collapse of the weir and to insure dynamic weir action and a waterfall off the upper edge of the weir during operation of the skimmer,
• said outer body having inner wall means which coact with the weir and second flotation means during skimming operation to form an air-filled chamber behind the weir within the cavity and below the surface level of the surrounding liquid body and which air chamber provides a positive buoyancy acting in a direction to lift the outer body upwardly,
• said inner wall means also coacting with the outer body to form a ballast chamber having a rear chamber in back of the air-filled chamber, as viewed in the direction of fluid flow through said opening and over the weir, and two side chambers extending along the two sides of the air-filled chamber,
• said weir-positioning means including ballast in the ballast chamber, a portion of which ballast is raised above the surface level of the surrounding liquid body by the positive buoyance of said air chamber,
• the amount and location of the raised ballast being so located with respect to the air chamber as to provide a negative buoyancy vertically balancing the positive buoyancy of the air chamber, and wherein the rear chamber contains an amount of ballast behind the air chamber sufficient to counter balance the amount of liquid within the skimmer in front of the weir and above the level of the liquid in the air chamber to maintain front-to-back equilibrium and to prevent front-to-back tilting of the skimmer, whereby the amount and location of the ballast coacts with the second flotation means to provide a self-compensating position of the weir for maintaining efficient skimming flow over the weir during varying conditions of operation of the skimmer, such as variations in the amount of effluent leaving the drain means and agitation of the surface of the surrounding liquid body.