Filter system for a liquid stream with automatic rapid back flush capability

A high efficiency liquid filter system which comprises at least one filtering set, each of which comprises:

• a generally cylindrical filter canister containing a porous tubular filter media within said canister;
• a first canister conduit connected to said canister adjacent to one end of said canister outside said tubular filter media and generally tangential to Said tubular filter media for liquid flow into and out of said canister on one side of said filter media;
• a second canister conduit connected to said canister axially within said tube for liquid flow into and out of said canister on the opposite side of said filter media;
• a first valve connected to said first canister conduit;
• a second valve connected to said second canister conduit:
• an influent conduit connected to said first valve and adapted to be connected to an influent pipe;
• a waste conduit connected to said first valve and adapted to be connected to a waste pipe;
• an affluent conduit connected to said second valve and adapted to be connected to an affluent pipe;
• a pressurized air line connected to said second valve;
• said first valve adapted to selectively connect said influent conduit to said first conduit to permit liquid to flow to said filter canister during filtering operation and connect said first canister conduit to said waste conduit during back wash operation to permit back wash liquid to flow from said filter canister to said waste pipe;
• said second valve adapted to selectively connect said second canister conduit from said filter canister to said affluent conduit during filtering operation to direct filtered liquid to said affluent pipe and to connect said air line to said second canister conduit to force clean affluent and air through said canister during back flush operation.

A high efficiency filter canister for filtering particles from a liquid stream which comprises:

• an elongated housing;
• a porous tube within said housing extending lengthwise of said housing and isolating the interior of said tube from the volume between said tube and the interior wall of said housing;
• a quantity of filter media covering the exterior of said porous tube;
• an outlet tube connected in fluid flow arrangement with the interior of said tube;
• an inlet tube connected in fluid flow arrangement with the volume outside the tube;
• and
• said inlet tube positioned approximately tangential to said porous tube and angled slightly toward the outlet tube connection;
• whereby liquid entering through said inlet tube will swirl along the surface of said filter media to substantially uniformly spread particles over the filter media.

A high efficiency liquid filter system which comprises at least one filtering set which comprises:

• a filter canister containing a generally tubular filter media;
• a first canister conduit connected generally tangentially to said canister and said tubular filter media for liquid flow into and out of said canister on one side of said filter media;
• a second canister conduit connected to said canister for liquid flow into and out of said canister on the opposite side of said filter media;
• a first valve assembly for selectively directing liquid flow from an influent pipe to said first canister conduit during filtering operation and directing liquid from said second canister conduit to a waste pipe during back flush operation;
• a source of high pressure gas;
• a second valve assembly adapted to selectively direct liquid from said second canister conduit to an affluent pipe during filtering operation and gas from said high pressure gas source to said second canister conduit during back flush operation;
• sensing means for sensing pressure drop across said filter media during filtering operation;
• and
• selection means for selecting the operational mode of said first and second valves in accordance with the sensed pressure drop across said filter media, said selection means comprising microprocessor means for receiving said sensed pressure drop and for operating said valves to back flush said filter media for a selected period at a selected degree of pressure drop.