Air cleaning apparatus

Claim 1

IN AN AIR CLEARNER: A DUST BOX INTO WHICH DUST LADEN AIR IS ADMITTED; A SERIES OF AIR FILTER POCKETS DISPOSED IN SPACED FACE-TO-FACE RELATION IN SAID DUST BOX TO FILTER SAID DUST LADEN AIR AS THE AIR FLOWS FROM THE OUTSIDE TO THE INSIDE OF SAID POSCKETS, EACH POCKET HAVING AN OPEN FRONT END; AN AIR CONTROL BOX ON THE FRONT SIDE OF SAID DUST BOX HAVING A SET OF FIRST CHAMBERS IN REGISTRY WITH AND CONNECTED TO SAID OPEN FRONT ENDS OF SAID POCKETS AND A SET OF COMPANION SECOND CHAMBERS ALTERNATING WITH SAID FIRST SET, SAID SECOND CHAMBERS BEING CONECTED IN COMMON WITH A SUCTION SOURCE; VALVE MEANS FOR EACH FIRST CHAMBER OPERABLE, IN A FIRST POSITION TO OPEN EACH FIRST CHAMBER TO ITS COMPANION SECOND CHAMBER AND TO CLOSE EACH FIRST CHAMBER TO ATMOSPHERE, AND IN AN ALTERNATE POSITION TO CLOSE EACH FIRST CHAMBER TO ITS COMPANION SECOND CHAMBER AND TO OPEN EACH FIRST CHAMBER TO ATMOSPHERE; AND MEANS FOR OPERATING THE VALVE MEANS OF EACH SUCCESSIVE FIRST CHAMBER TO SAID ALTERNATE POSITION FOR A TIME INTERVAL OVERLAPPING AT LEAST A PART OF THE TIME INTERVALS DURING WHICH THE VALVE MEANS OF THE IMMEDIATELY PRECEDING AND SUCCEEDING ADJACENT FIRST CHAMBERS ARE IN SAID ALTERNATE POSITIONS WHEREBY A REVERSE FLOW OF AIR IS INDUCED THROUGH THOSE SUCCESSIVE PAIRS OF FILTERS POCKETS CONNECTED WITH SAID FIRST CHAMBERS HAVING VALVE MEANS IN SAID ALTERNATIE POSITION.