Blow back dampers are used on the inlet of hazardous collectors. They ensure no re-entrainment occurs when the blower is off. It also ensure there is a seal, if a fire occurs, stopping the smoke from returning to the shop via the ductwork.
The hinged door swings open under vacuum to let the air and the particles into the dust collector’s inlet. When the blower is turned off, the door of the blow back damper drops down and closes itself via gravity, ensuring that no re-entrainment occurs. The valve of the blow back damper also acts as a seal in case of a fire, preventing the smoke from going back to the shop.
The Airex Industries line of blow back dampers range from 6″ to 42″. Blow back dampers are constructed of heavy-duty metal, and custom sizes are available.
