Filter

Claim 1

A filter for treating liquids, comprising: a filter compartment having a filter bed separating it into an upper inlet chamber and a lower underdrain chamber; an inlet pipe, having a control valve means associated therewith, communicating with said inlet chamber; a backwash storage compartment positioned adjacent said filter compartment; a connecting pipe having a first end extending into said underdrain chamber and a second end in communication with a backwash pump means; said pump means constructed and arranged to permit the flow of filtered liquid from said underdrain chamber through said connecting pipe to pass directly therethrough into said backwash storage compartment; blower means for delivering air through an air supply conduit into said underdrain chamber; control means including a level sensing switch means positioned within said inlet chamber, said control means constructed and arranged for sequentially closing said control valve means, activating said blower means for a period of time, activating said pump means for a period of time and reopening said control valve means, when the liquid in the inlet chamber reaches a predetermined level; said first end of said connecting pipe includes a float valve means associated therewith which permits the passage of liquid therethrough until the level of liquid within said underdrain chamber drops to the level of said float valve means; said air supply conduit communicates with said underdrain chamber at a level above said float valve means such that the air entering said underdrain chamber forces liquid within said chamber through said float valve means and said connecting pipe into said backwash storage compartment until the level drops to the level of said float valve means; and an effluent pipe associated with said backwash storage compartment for removal of filtered liquid therefrom to service.