Product Description

The Square Multi-Blade Backdraft Damper is designed to prevent reverse airflow in HVAC and ventilation duct systems. It features multiple lightweight blades that open automatically when air moves in the intended direction and close by gravity when airflow stops or reverses. This design helps protect the ventilation system from unwanted backflow, outside air intrusion, dust entry, and pressure loss.

Compared with single-blade models, the multi-blade structure provides more stable operation and is especially suitable for rectangular duct openings and larger air passages. It is widely used in commercial, industrial, and residential ventilation systems for exhaust air control and non-return protection.

Manufactured from galvanized steel, aluminum, or stainless steel as required, the damper offers reliable performance, corrosion resistance, and long service life. It can be installed in ductwork, wall openings, fan outlets, or air handling systems.

Key Features

• Backdraft Prevention  Prevents reverse airflow when the fan stops or external pressure changes
• Multi-Blade Design  Multiple blades ensure stable opening and closing performance
• Gravity Operated  Blades open automatically with forward airflow and close by gravity without power
• Low Resistance  Lightweight blades help reduce pressure drop during operation
• Durable Construction  Available in galvanized steel, aluminum, or stainless steel
• Rectangular Configuration  Suitable for square and rectangular duct systems
• Easy Installation  Can be mounted in ducts, wall sleeves, exhaust outlets, or ventilation terminals
• Low Maintenance  Simple mechanical structure with no motor or complex control parts

Applications

• HVAC duct systems
• Exhaust air systems
• Commercial ventilation
• Industrial ventilation
• Wall-mounted exhaust openings
• Fan discharge outlets
• Air handling units and ventilation terminals
• Return airflow prevention in rectangular ducts

Technical Specifications