For automatic shutoff of the air ducts and prevention of back drafting when the fan is off. Suitable for installation in various premises. Compatible with Ø 100 up to 315 mm round air ducts.
Galvanized steel case. Two spring-loaded blades made of aluminium. Blades are opened by air pressure and are closed with a spring.
Fixing to round ducts with clamps. Provide vertical position of blade axis. Install the backdraft damper into the ventilation system with respect to the air flow direction.