Dynamic self-cleaning filter for liquids

Claim 1

A continuous self-cleaning filter device for liquids comprising an elongated cylindrical outer tube having a wall of integral homogeneous resonant material, a non-resonant support for the tube at each end at respective wave length nodal points, said tube being free of support between said ends, a composite cylindrical inner tube of diameter smaller than said outer tube and concentric with respect to said outer tube forming an elongated annular chamber therebetween, a sealing support structure at each end of said chamber holding the respective ends of the tubes in spaced concentric relationship and holding said tubes intermediate said ends out of engagement with each other, an inlet passageway adjacent one end of said annular chamber for liquid to be filtered, an outlet passageway adjacent the other end of the chamber for discharge of fluid residue and a liquid pressure restricted control means in said outlet passageway productive of a condition wherein said annular chamber and said tubes are substantially continuously filled with liquid, said composite tube comprising a relatively thin-walled inner cylindrical liner having a perforated wall structure with inner and outer relatively hard surfaces, and a blanket of filter material over the outer surface of said wall structure pervious to the passage of liquid filtrate and impervious to the passage of filter pack solid material, there being a substantially clear central chamber in said liner with an opening at one end for collection and discharge of clear filtrate, and a continuously operating sinusoidal frequency energy inducing transducer having a fixed attachment to the wall of the outer tube on the exterior at a sonic wave length antinodal point relative to the ends of the outer tube, said outer tube in response to action of said transducer being continuously in resonance throughout its length and circumference in a sinusoidal wave pattern, said outer tube and the liquid in said annular chamber and in said blanket of filter material being in a resonant condition productive of a condition of continuous cavitation in the liquid in the chamber and the liquid in the blanket of filter material whereby to continuously dislodge residue from the blanket.