Vacuum

A vacuum device comprising:

• a tank portion including a collection chamber;
• a head portion having an airflow assembly including an airflow generating device operable to generate airflow within the vacuum device such that an intake airstream is drawn into the collection chamber via an air inlet and an exhaust airstream is exhausted from the collection chamber via an exhaust outlet;
• a first filter disposed within the tank collection chamber;
• a second filter disposed within the tank collection chamber;
• a separator between the air flow assembly and the tank portion, the separator including;
• a first passageway through the separator and in fluid communication with the first filter, the first passageway allowing airflow between the collection chamber and airflow generating device, and a second passageway through the separator and in fluid communication with the second filter, the second passageway allowing airflow between the collection chamber and airflow generating device;
• and the airflow assembly further including, a third passageway in fluid communication with the first filter, the third passageway allowing airflow between the first filter and an air source outside the collection chamber;
• and a fourth passageway in fluid communication with the second filter, the fourth passageway allowing airflow between the second filter and the air source outside the collection chamber;
• and a valve assembly operable to selectively and independently permit airflow between at least one of the first filter and the airflow generating device or the outside air source and between the second filter and the airflow generating device or the outside air source;
• and
• wherein the valve assembly includes at least two butterfly valves each including a shaft and two offset gates secured to the shaft, the offset gates alternately mating with two respective air passage seats to alternately open one of the first and second passageways while simultaneously closing one of third and fourth passageways.