Patent ID: 7093721

Claim:
A filter assembly comprising: a housing defining an enclosed space, said housing having an inlet opening into the enclosed space and an outlet opening from the enclosed space; a filter element disposed in the enclosed space within said housing, wherein said filter element is positioned in said housing so that a process stream introduced into the enclosed space through said inlet opening flows through said filter element prior to discharge through said outlet opening and said filter element has a surface against which filtrate is trapped as the process stream flows through said filter element; a cleaning head disposed in the enclosed space within said housing and having at least one cleaning blade positioned to abut the surface of said filter element; a sealed tube within the enclosed space of said housing; a first magnet disposed in said sealed tube so as to move within said sealed tube; an actuator assembly connected to said sealed tube or said first magnet for selectively moving said first magnet in said sealed tube; and a second magnet located in the enclosed space in said housing and located adjacent and external to said sealed tube, said second magnet being magnetically coupled to said first magnet to move along said sealed tube with the movement of said first magnet and being attached to said cleaning head so that said cleaning head moves with said second magnet, wherein: said sealed tube has opposed top and bottom ends and said first magnet is disposed in said sealed tube so as to be move between the top and bottom ends; an air tube is connected to said sealed tube and opens into the top end of said sealed tube; said actuator assembly includes: a first air line connected to said sealed tube through which gas can be supplied to the bottom end of said sealed tube; a second air line connected to said air tube through which gas can be supplied to said air tube to the top end of said sealed tube; a source of compressed gas; and a flow control assembly connected at one end to said first and second air lines and, at a second end to said source of compressed gas for directing the flow of compressed gas to said first air line or to said second air line.