Liquid and solids separation apparatus and method with continuous cleaning using defferential pressure control

A filtering apparatus for separating solids from a liquid, comprising

• a cylindrical filter housing having an inlet for the introduction of unfiltered fluid on one end of said cylindrical housing and an having an outlet permitting discharge of filtered fluid on the opposing end of said cylindrical housing;
• a rotation drive shaft disposed along the longitudinal axis of said cylindrical filter housing and supported therein;
• an annular filter means disposed intermediate said cylindrical filter housing and rigidly supported therein and having a central opening, said rotation drive shaft sealingly and rotatably disposed through the central opening of said annular filter means;
• said annular filter means defining an inlet chamber in fluid communication with said inlet and defining an outlet chamber in fluid communication with said outlet;
• said annular filter means for intercepting solids from a liquid containing solids;
• said annular filter means having an inlet side and an outlet side;
• said inlet chamber being in fluid communication with said outlet chamber through said filter means;
• a pump means in fluid communication with said outlet chamber for receiving filtered fluid from the outlet chamber and for pressurizing said filtered fluid;
• said pump means having a pressurized fluid outlet;
• a pressurized filtered fluid housing comprising an elongate pressurized filtered fluid hood having a pressurized filtered fluid inlet therein;
• said pressurized filtered fluid housing mounted for rotation about the longitudinal axis of said cylindrical filter housing and connected to said rotation drive shaft;
• said pressurized filtered fluid hood comprising at least one cleaning shoe;
• said cleaning shoe slidably and sealingly engaged with a portion of said outlet side of the annular filter means;
• said cleaning shoe having a radially extending slit therethrough which provides fluid communication between a substantial radially elongate area on said outlet side of the annular filter means and an interior of said pressurized filtered fluid housing wherein the interior of said pressurized filtered fluid housing is separated from said outlet chamber;
• said pressurized filtered fluid inlet connected by conduit to the pressurized fluid outlet of the pump means;
• a backwashed fluid housing comprising an elongate backwashed fluid hood having a backwashed fluid outlet for discharging backwashed fluid and solids out of said cylindrical filter housing;
• said backwashed fluid housing connected to said rotation drive shaft and mounted for rotation about the longitudinal axis of said cylindrical filter housing in synchrony with said pressurized filtered fluid housing;
• said backwashed fluid hood comprising a number of backwash shoes equal to the number of cleaning shoes;
• each said backwash shoe slidably and sealingly engaged with a portion of said inlet side of the annular filter means and aligned opposing a cleaning shoe;
• each said backwash shoe having a radially extending slit therethrough which provides fluid communication between a substantial radially elongate area on said inlet side of the annular filter means and an interior of said backwashed fluid housing wherein the interior of said backwashed fluid housing is separated from said inlet chamber and wherein there is fluid communication between the radially extending slit of each said cleaning shoe through a substantial radially elongate area of the annular filter means and with the radially elongate slit on each said opposing backwash shoe;
• a drive means connected to said rotation drive shaft for providing rotation of said rotation drive shaft, wherein rotation of said drive shaft causes rotation of said pressurized filtered fluid housing and said backwashed fluid housing around the longitudinal axis of the cylindrical filter housing and wherein said annular filter means is cleaned by backwashed pressurized filtered fluid in the area covered by said cleaning shoe and the opposing backwash shoe, cleaning occurring simultaneously with filtering over the remainder of the surface of the annular filter means, the entire annular filter means being washed successively during each completed revolution of said rotation drive shaft.

A method of filtering solids from a fluid and backwashing a filter comprising passing unfiltered fluid from an intake fluid volume through a filter element to an outlet fluid volume to filter solids from said unfiltered fluid and deposit said solids on and in said filter element;

• providing a pressurized filtered fluid housing disposed on the outlet side of said filter element and having a slot arrangement arranged to engage a portion of said filter element;
• providing a backwashed fluid housing disposed on the inlet side of said filter element opposing said pressurized filtered fluid housing and having a slot arrangement arranged to engage said portion of said filter element wherein there is fluid communication between said pressurized filtered fluid housing through said portion of said filter element and to said backwashed fluid element;
• suctioning a portion of filtered fluid from the outlet fluid volume;
• pressurizing said portion of suctioned filtered fluid to a pressure in excess of the fluid pressure of the intake fluid volume;
• passing said pressurized filtered fluid through said pressurized filtered fluid housing to backwash solids from said filter element;
• collecting backwashed fluid and solids through said backwashed fluid housing;
• discharging said backwashed fluid and solids;
• producing synchronous movement of said pressurized filtered fluid housing and said backwashed fluid housing relative to said filter element so that pressurized filtered fluid is passed through said pressurized filtered fluid housing and through portions of said filter element to said backwash fluid housing to backwash solids collected on said fluid element.