Abstract

A vacuum filter for vacuum flow filtration through a filter bed of water from a swimming pool is provided, comprising an open-top tank; a filter bed of particulate material in the tank; fluid flow connections communicating the tank with a water recirculation system for the swimming pool, one adjacent an upper portion and one adjacent a lower portion of the filter bed; an inlet line communicating the swimming pool with the tank and maintaining the level of water in the tank at a level corresponding to a level of water in the swimming pool, thereby providing a head of water for gravity backwash flow through the filter bed, and valves controlling flow into the tank via the fluid flow connections between the tank and the inlet line, and between the tank and the water recirculation system; and a direct fluid flow connection communicating a gutter drain of the swimming pool with the tank; a vacuum is drawn downstream of the filter bed by a pump recirculating filtered water to the swimming pool.In a preferred embodiment, the tank has a dividing wall extending across the tank and separating the tank into first and second compartments; a filter bed of particulate material in the second compartment; two fluid flow connections communicating the two compartments, one adjacent an upper portion and one adjacent a lower portion of the filter bed; two fluid flow connections communicating the second compartment with a water recirculation system for the swimming pool, one adjacent an upper portion and one adjacent a lower portion of the filter bed; an inlet line communicating the swimming pool with the first compartment and maintaining the level of water in the first compartment at a level corresponding to the level of water in the swimming pool, thereby providing a head of water for gravity backwash flow through the filter bed.