Easily assembled filter assembly

Claim 1

A FILTER COMPRISING A PRESSURE TIGHT HOUSING, HAVING LOWER AND UPPER FACING END MEMBERS, A SUBSTANTIALLY CYLINDRICAL HOLLOW FILTER STACK HELD UNDER ENDWISE COMPRESSION WITHIN SAID HOUSING BY AND BETWEEN SAID END MEMBERS, SAID LOWER END MEMBER HAVING INLET AND OUTLET PASAGES AND A CENTRAL CAVITY COMMUNICATING WITH SAID OUTLET PASSAGE, SAID UPPER END MEMBER HAVING A CENTRAL CAVITY COMMUNICATING WITH THE CENTER OF SAID STACK, A NON-CIRCULAR IMPERMEABLE COLLECTOR TUBE SUPPORTED IN SAID LOWER CENTRAL CAVITY IN FLUID TIGHT ENGAGEMENT THEREWITH AND PASSING AXIALLY INTO SAID UPPER CAVITY, SAID COLLECTOR TUBE FACE THEREOF INTO SAID UPPER CAVITY, SAID COLLECTOR TUBE HAVING AT LEAST ONE OPENING ADJACENT ITS UPPER END AND AXIALLY BEYOND SAID UPPER SURFACE AND RADIALLY EXTREMEAND AXIALLY EXTENDING LAND-LIKE SURFACES ENGAGING THE INTERIOR PERIPHERAL WALLS OF SAID STACK AND SAID UPPER CAVITY TO AFFECT TRANS-AXIAL ALIGNMENT THEREBETWEEN AND TO DEFINE, IN CONJUNCTION WITH SAID PERIPHERAL WALLS, A PLURALITY OF AXIALLY EXTENDING PASSAGES STRETCHING FROM SAID LOWER MEMBER TO SAID CENTRAL CAVITY WITHIN SAID UPPER MEMBER AND COMMUNICATING WITH THE INTERIOR OF SAID TUBE, AND MEANS FOR MAINTAINING SAID HOUSING, SAID STACK AND SAID TUBE IN PRESSURE TIGHT CONDITION WITH RESPECT TO EACH OTHER, WHEREBY FLUID ENTERING SAID FILTER SERIALLY PASES THROUGH SAID STACK, VERTICALLY UPWARD THROUGH SAID AXIALLY EXTENDING PASSAGES, THENCE DOWNWARDLY THROUGH SAID COLLECTOR TUBE AND OUTWARD FROM SAID OUTLET PORT.