Oil filter with relief valve

Claim 1

IN A DISPOSABLE FILTER CARTRIDGE INCLUDING COAXIAL OUTER AND INNER PREVIOUS AN CYLINDRICAL WALLS PROVIDING A FILTERING CHAMBER HAVING FILTERING MATERIAL THEREIN, AND IMPERVIOUS ANNULAR END WALL MEMBERS CLOSING THE ENDS OF SAID CHAMBER, SAID CYLINDRICAL WALL COMPRISING A TUBE OPEN AT ONE END TO PERMIT DISCHARGE OF FLUID FROM THE CARTRIDGE; A RELIEF VALVE ASSEMBLY MOUNTED AT THE END OF SAID CARTRIDGE OPPOSITE SAID DISCHARGE END AND FORMING A UNITARY PART THEREOF, COMPRISING AN ANNULAR VALVE CASING HAVING A SLEEVE PROJECTING AXIALLY THEREFROM AND SNUGLY FITTING WITIN AN END OF SAID INNER PERVIOUS WALL, SAID CASING MEMBER HAVING AN IMPERFORATE PERIPHERAL WALL, AN IMPERFRATE INNER END WALL SEPARATE FROM THE ADJACENT CARTRIDGE END WALL AND AN OUTER END WALL HAVING END OPENINGS THEREIN, SAID VALVE CASING MEMBER BEING FLANGED RADIALLY OUTWARDLY FROM SAID SLEEVE MEMBER AND BEING OF RELATIVELY SMALL THICKNESS AS COMPARED WITH ITS DIAMETER SO THAT THE VALVE CASING PROJECTS ONLY A SHORT DISTANCE AXIALLY BEYOND THE END WALL OF THE CARTRIDGE PROPER, AN ANNULAR VALVE HOUSED IN SAID CASING AND AXIALLY RECIPROCABLE THEREIN, AND MEANS COMPRISING A COIL SPRING NORMALLY URGING SAID VALVE TO CLOSED POSITION AGAINST SAID END OPENINGS, SAID COIL SPRING BEING PRINCIPALLY HOUSED IN THE SLEEVE PORTION OF THE WALL CASING WHICH PROJECTS INTO THE INNER WALL PORTION OF THE CARTRIGE, SAID ANNULAR VALVE MEMBER BEING RELATIVELY THIN AS COMPARED TO THE