Backdraft dampers are intended to protect against backdrafts in HVAC units. They're installed in exhaust ducts to stop the reverse movement of air. Backdraft dampers are generally set up in spots where unfavorable pressure may occur, for instance loos and kitchens. Multi-blade ventilation dampers supply precise, variable control of airflow https://air-control-dampers-for-h79011.full-design.com/air-control-dampers-for-engine-sheds-an-overview-78840953