Filter unit for welding apparatus

Claim 1

A FLUID FILTER UNIT, COMPRISING A HOUSING COMPRISING TWO, GENERALLY CYLINDRICAL, CAN-SHAPED SECTIONS HAVING THEIR OPEN ENDS RELEASABLY AND SEALINGLY SECURED TOGETHER WITH ONE SECTION DISPOSED COAXIALLY ABOVE THE OTHER SECTION, A TRANSVERSE PARTITION MOUNTED IN THE LOWER OF SAID TWO HOUSING SECTIONS INTERMEDIATE ITS ENDS AND HAVING THEREIN A CENTRAL OPENING, AN ELECTRIC MOTOR MOUNTED ON THE UPPER OF SAID TWO HOUSING SECTIONS, AN IMPELLER MOUNTED ON THE UPPER END OF SAID UPPER HOUSING SECTION IN REGISTRY WITH AN OPENING THEREIN, AND CONNECTED TO SAID MOTOR FOR ROTATION THEREBY ABOUT AN AXIS COAXIALLY WITH SAID HOUSING TO APPLY A VACUUM TO THE INSIDE OF SAID HOUSING THROUGH SAID OPENING IN THE UPPER SECTION OF SAID HOUSING, A SINGLE ANNULAR FILTER CARTIDGE REMOVABLY FIXED AT ITS UPPER END TO THE UPPER END OF SAID UPPER HOUSING SECTION COAXIALLY THEREOF AND PROJECTING DOWNWARDLY INTO SAID LOWER SECTION IN RADIALLY SPACED RELATION TO THE INSIDE OF SAID HOUSING, SAID IMPELLER HAVING AN INLET SIDE COMMUNICATING THROUGH SAID OPENING IN THE UPPER END OF SAID HOUSING WITH THE BORE IN SAID CARTIDGE, AND HAVING AROUND ITS PERIPHERY AN OUTLET FOR EXHAUSTING FLUID OUTWARDLY THEREFROM DURING USE, SAID CARTIDGE HAVING A CLOSED, TRANSVERSELY EXTENDING LOWER END POSITIONED ABOVE AND IN SPACED RELATION TO THE OPENING IN SAID PARTITION, MEANS EXTENDING THROUGH THE BORE IN SAID CARTIDGE FOR RELEASABLY ATTACHING ITS CLOSED, LOWER END TO THE UPPER END OF SAID UPPER HOUSING SECTION, AND A DUCT SECURED IN AN INLET OPENING IN SAID LOWER HOUSING SECTION BENEATH SAID PORTION, AND EXTENDING AT ITS OPPOSITE END EXTERIORLY OF SAID HOUSING FOR CONVEYING THE FLUID TO BE FILTERED INTO SAID LOWER SECTION BENEATH SAID PARTITION, SAID DUCT HAVING AN AXIS EXTENDING TRANSVERSE TO THE AXIS OF SAID HOUSING AND BEING CONSTRUCTED AND ARRANGED, WHEREBY, UPON OPERATION OF SAID MOTOR, FLUID DRAWN THROUGH SAID DUCT IS FIRST SWIRLED IN CYCLONIC FASION IN SAID LOWER SECTION TO REMOVE PARTICLES THEREFROM BY A COMBINATION OF CENTRIFUGAL AND GRAVITATIONAL FORCES, AND THEN PASSES UPWARDLY THROUGH THE OPENING IN SAID PARTITION TO IMPINGE AGAINST AND TO PASS AROUND THE CLOSED END OF SAID CARTIDGE INTO THE ANNULAR SPACE BETWEEN SAID CARTIDGE AND THE INSIDE WALL OF SAID HOUSING, AND FROM SAID SPACE THROUGH SAID CARTIDGE AND ITS BORE AND THE OPENING IN THE UPPER END OF SAID IMPELLER.