Multi-stage filter system

Claim 1

A MULTI-STAGE FILTER COMPRISING, IN COMBINATION: A HOLLOW SEALED GENERALLY CYLINDRICAL HOUSING; A SEALED CYLINDRICAL CASING DISPOSED WITHIN THE UPPER PORTION OF SAID HOUSING, SAID CASING HAVING UPPER AND LOWER COVERS; INNER AND OUTER CYLINDRICAL VERTICAL WALLS CONNECTED TO SAID COVERS, SAID INNER WALL BEING PROVIDED NEAR ITS UPPER END WITH A PLURALITY OF OUTLET HOLES THERETHROUGH, SAID UPPER COVER AND OUTER WALL BEING IMPERFORATE AND SAID LOWER COVER HAVING A PLURALITY OF ANGULARLY SPACED APART INLET HOLES THERETHROUGH AND COMMUNICATING WITH THE INTERIOR OF THE CASING BETWEEN THE INNER AND OUTER CYLINDRICAL WALLS; A BODY OF FILTER MATERIAL SUBSTANTIALLY FILLING THE INTERIOR OF SAID CASING; A VERTICAL OUTLET TUBE EXTENDING CONCENTRICALLY UP INSIDE SAID HOUSING AND CASING WITH THE UPPER AND LOWER COVERS BEING SEALED TO THE OUTLET TUBE, SAID OUTLET TUBE NEAR ITS UPPER END AND BETWEEN SAID COVERS HAVING AN OPENING THERETHROUGH ADAPTED TO CONVEY FILTERED LIQUID WHICH HAS PASSED UP THROUGH SAID BODY OF FILTER MATERIAL AND THROUGH SAID OUTLET HOLES; A LONG ANNULAR FILTER MOUNTED IN SAID HOUSING BELOW SAID CASING, SAID FILTER HAVING A FABRIC OUTER WALL SPACED FROM SAID HOUSING TO PROVIDE AN ANNULAR PASSAGE THEREBETWEEN AND A FABRIC CYLINDRICAL INNER WALL CONCENTRIC WITH SAID OUTLET TUBE AND SPACED THEREFROM TO PROVIDE THEREBETWEEN A VERTICAL FLOW PASSAGE WHICH COMMUNICATES DIRECTLY WITH THE INLET HOLES IN SAID LOWER COVER, SAID FILTER HAVING A POROUS TOP WALL PRESSING AGAINST SAID LOWER COVER TO SUPPORT THE ENTIRE WEIGHT OF SAID CASING AND MEANS AT THE BOTTOM THEREOF FOR SEALING SAID ANNULAR PASSAGE FROM SAID VERTICAL FLOW PASSAGE; AND MEANS FOR CONVEYING PRESSURIZED LIQUID TO BE FILTERED INTO SAID ANNULAR PASSAGE TO SUBSTANTIALLY FILL SAID PASSAGE WHEREBY THE LIQUID PASSES RADIALLY INWARD THROUGH SAID POROUS FABRIC AND ANNULAR FILTER AND THEN UPWARD THROUGH SAID VERTICXAL FLOW PASSAGE AND THE INLET HOLES IN SAID LOWER COVER AND SAID BODY OF FILTER MATERIAL.