Patent ID: 6517712
Filing Date: 2003-02-11
Classification: B01D

Abstract:
A liquid filtering apparatus comprising:a vessel; a bed of filtration material within said vessel; an intake for introducing into an upper region of said vessel an influent liquid to be filtered, said liquid being filtered by gravitationally descending through the bed to a lower region of said vessel; an enclosure in said bed for collecting said filtered liquid; an outlet for transporting said filtered liquid from said enclosure; an airlifting tube for conveying a mixture of said filtration material dirtied by particulates taken from said liquid to be filtered and a portion of said filtered liquid from the lower region of said vessel to the upper region of said vessel, said airlifting tube terminating at a washbox; said washbox comprising a washbox body and a filter media shield hood for deflecting said dirtied filtration material; a washbox skirt below said filter media shield hood wherein said filtration material is washed in an enlarged section defining a washbox filter media separation area with a portion of said influent liquid entering into said washbox skirt through at least one cleaning water inlet nozzle wherein said enlarged section is beneath said washbox body and above said at least one cleaning water inlet nozzle: a washbox isolator at the bottom of said washbox skirt through which the washed filtration material is reintroduced to an upper region of said bed; a dirtied liquid reject line for conveying from the washbox, the influent liquid which has washed the filtration material; and means for introducing a primary gas to said airlifting tube to induce flow of said dirtied filtration material to said washbox.