Dustless regenerative air sweeper

Abstract

A closed-loop Regenerative.RTM. air sweeper is provided which constitutes an improvement of that disclosed in U.S. Pat. No. 3,512,206. The sweeper of the latter patent is provided as an integral portion thereof, whereas a conversion, a 'dustless' mechanism having first and second chambers into the first chamber of which is directed a portion of the air stream from a pressure conduit associated with a pickup head of the sweeper. Particles of debris are separated by cyclone separators and thereafter by membrane filters after which substantially clean air is discharged to atmosphere. Air entrained particles separated by the cyclone separators and the cartridge filters are returned to a vacuum side of the pickup head thereby maintaining substantially closed-loop air flow of the sweeper. Clean air is controllably exhausted to atmosphere by flue vanes which can be selectively moved under pressure differential sensing means associated with the cyclone separator. The pressure in the two air chambers is also sensed with the read-out thereof being in an instrument panel to permit an operator to monitor and diagnose the system. Pulses of high pressure air are utilized to clean the membrane filter and a pop-off valve serves as an emergency vent to atmosphere under undesired high pressure within the second chamber of the housing. An extremely important aspect of the present invention is that achieved by creating and maintaining a substantially negative pressure at and across the pickup head. The latter is achieved by assuring that the air drawn into the pickup head is approximately a nominal ten percent (10%) and the clean air discharged to atmosphere is maintained at the substantially the same nominal ten percent (10%) through appropriately operating a valve under the control of a pressure differential sensor which measures pressure drop across the cyclone separators.