US Patent 9271620 Vacuum

The present invention is directed to a vacuum including a dust extraction system. The system includes a filter assembly, an airflow generation assembly, and valve assembly. The airflow generation assembly is configured to draw contaminated air toward the filter assembly and exhaust filtered air as a discharge stream. The filter assembly is configured to remove contaminants from the contaminated airflow by capturing particulate material suspended within the airflow. The valve assembly is configured to selectively direct filtered airflow into the filter assembly such that the filtered air stream cleans the filter.