Self-cleaning air filter

Abstract

The self-cleaning air filter uses reverse pulse self-cleaning for small scale, small volume air filtration applications, such as vehicles and motorized equipment. The self-cleaning air filter includes a filter casing, a filter element housed within a filter casing, an electronically controlled pulse valve that releases the compressed air pulse, and a pulse pressure relief vent. During the cleaning cycle, the pulse pressure vent opens to vent the compressed air pulse to the atmosphere thereby maintaining the positive pressure differential between the inside and outside of the filter element, which sustains the cleaning action for the duration of the compressed air pulse.

1 - 7 . (canceled) 
     
     
         8 . A self-cleaning air filter apparatus connected to an associated compressed air source comprising:
 a filter casing including an opening in a wall thereof;   a filter element disposed within the filter casing such that an interior volume is defined within the filter element and an exterior volume is defined between the filter element and the wall of the filter casing, whereby during a filtering cycle a negative pressure differential between the interior volume and the exterior volume draws airflow inward through the filter element and during a self-cleaning cycle a positive pressure differential between the interior volume and the exterior volume forces airflow outward through the filter element,   a valve in communication with the filter casing and connected to the associated compressed air source for selectively releasing a pulse of compressed air into the interior volume whereby dust is dislodged from an exterior surface of the filter element into the filter casing; and   a vent mounted over the opening in the filter casing wall for venting the pulse of compressed air from the filter casing to maintain a positive pressure differential between the interior volume and the exterior volume during the cleaning cycle, the vent comprising a frame, a blocking element mounted for reciprocation between an open position and a closed position in relation to the frame and a biasing element for urging the blocking element into the closed position.   
     
     
         9 . The apparatus of  claim 8  wherein the vent opens at a selected internal pressure within the filter casing. 
     
     
         10 . The apparatus of  claim 8  wherein the blocking element extends in a single plane when in the closed position. 
     
     
         11 . The apparatus of  claim 8  wherein the blocking element is flexible. 
     
     
         12 . The apparatus of  claim 8  wherein the vent further comprises a cover plate mounted to the filter casing via spacers. 
     
     
         13 . The apparatus of  claim 12  wherein the blocking element is disposed between the cover plate and the opening in the filter casing. 
     
     
         14 . The apparatus of  claim 8  wherein the vent is mounted to the filter casing between a first end of the filter casing and a second end of the filter casing. 
     
     
         15 . The apparatus of  claim 8  wherein the valve includes a nozzle extending into the interior space for directing the compressed air pulse laterally through the filter element. 
     
     
         16 . The apparatus of  claim 8  wherein the vent further comprises a stop spaced from the filter casing and wherein the blocking element is positioned between the stop and the filter casing. 
     
     
         17 . The apparatus of  claim 16  wherein the stop comprises a cover plate. 
     
     
         18 . The apparatus of  claim 16  wherein the biasing element is positioned between the stop and the blocking element.