Air filter assembly

Claim 1

AN ASSEMBLY FOR FILTERING FORCED AIR COMPRISING A FILTER HAVING A HOUSING, A VERTICAL BORE IN SAID HOUSING, A SLEEVE INSERTED INTO SAID SEATED IN SAID BORE, A SUMP IN A LOWER PART OF SAID HOUSING BELOW SAID BORE, A VERTICALLY DIRECTED HELICAL GROOVE IN AN EXTERNALLY FINNED HELICALLY CONVOLUTED PORTION OF THE SIDE WALL OF SAID HOUSING ABOUT SAID BORE AND CLOSED INWARDLY BY SAID SLEEVE THEREBY DEFINING A HELICAL PASSAGE, SAID PASSAGE FLUIDLY COMMUNICATING AT ITS UPPER END WITH AN INLET PORT IN SAID HOUSING AN AT ITS LOWER END WITH SAID SUMP AND DIRECTING FORCED AIR INTRODUCED THROUGH SAID PORT DOWNWARDLY IN A FIXED HELICAL PATH FOR CENTRIFUGALLY SEPARATING CONTAMINANTS FROM AND COOLING SAID AIR AND DISCHARGING SAID SEPARATED CONTAMINANTS AND FILTERED AIR INTO SAID SUMP, A TUBE EXTENDING UPWARDLY THROUGH SAID SLEEVE FROM A CONTAMINANT CAVITY IN A BOTTOM OF SAID SUMP AND HAVING A PASSAGE THERETHROUGH FOR PASSING CONTAMINANTS UPWARDLY FROM SAID CAVITY, A FILTERED AIR PASSAGE IN SAID SLEEVE BETWEEN SAID SLEEVE AND SAID TUBE FOR PASSING FILTERED AIR UPWARDLY TO AN OUTLET PORT IN SAID HOUSING FROM SAID SUMP, AND DRAIN VALVE MEANS SURMOUNTING SAID HOUSING AND CONNECTED TO SAID CONTAMINANT PASSAGE FOR DRAINING CONTAMINANTS FROM SAID SUMP UNDER PRESSURE OF SAID AIR.