Virtual impactor filter assembly and method

A filter system comprising:

• a filter housing having a cylindrical sidewall defining an interior chamber, the filter housing having an inlet opening extending into the interior chamber, the cylindrical sidewall including a plurality of exit openings extending therethrough;
• a filter medium disposed in the interior chamber of the filter housing along an inner surface of the cylindrical sidewall;
• and
• an outer air flow housing having an outlet conduit through which a flow of air having particles is directed toward the inlet opening of the filter housing along a flow direction toward the interior chamber of the filter housing, the outer air flow housing spaced a separation distance from the inlet opening of the filter housing;
• and
• a volume defined between the filter housing and the outer air flow housing along the flow direction to permit at least some of the flow of air to flow, via the separation distance, through the volume and pass around an exterior of the filter housing, and exit the outer air flow housing while the particles in the at least some of the flow of air pass into the interior chamber of the filter housing through the inlet opening, and wherein the filter medium removes particles from the flow of air to provide a filtered air flow that exits the filter housing through the plurality of exit openings wherein the filter housing engages the outer air flow housing such that the filter housing is separated from the outer air flow housing along the flow direction by an air gap.

A virtual impactor filter assembly comprising:

• a filter housing having a cylindrical sidewall defining an interior chamber, the filter housing including an inlet opening positioned relative to an outer air flow housing that directs a flow of air having particles along a flow direction into the interior chamber of the filter housing through the inlet opening, the cylindrical sidewall including a plurality of exit openings extending therethrough;
• a filter medium disposed in the interior chamber of the filter housing along an inner surface of the cylindrical sidewall, the filter medium removing particles from the flow of air having particles to provide a filtered air flow that exits the filter housing through the plurality of exit openings;
• and
• a bridge conduit configured to extend from an outlet opening of the outer air flow housing through which the air is directed toward the filter housing to the inlet opening of the filter housing, the bridge conduit including openings that allow the air to flow out of the bridge conduit prior to reaching the inlet opening of the filter housing and around the filter housing,
• wherein the filter housing is separated from the outer air flow housing along the flow direction to permit at least some of the flow of air to pass around an exterior of the filter housing, and exit the outer air flow housing while the particles in the at least some of the air pass into the interior chamber of the filter housing through the inlet opening.