Opposed Blade Damper

Opposed blade damper, short for OBD damper, is a rectangular multi-blade volume control damper dedicated to HVAC air distribution systems. Equipped with interlinked counter-rotating blades, this air balancing damper achieves stable, low-turbulence airflow regulation for supply and return air pipelines. Available in aluminum and galvanized steel materials with manual or motorized control options, it supports flexible installation behind grilles, diffusers and duct sections. Featuring customizable frame depth and custom sizing service, it is extensively supplied to commercial buildings, industrial ventilation and air terminal OEM manufacturers for accurate airflow adjustment during installation and daily operation.

Product Description

The Opposed Blade Damper (OBD) is a reliable airflow control component designed for HVAC duct systems, air terminals, grilles, and diffusers. It is equipped with multiple blades linked to rotate in opposite directions, providing smooth, stable, and uniform airflow regulation across the full opening area. Compared with simple single-blade dampers, the opposed blade structure offers more accurate balancing performance, lower turbulence, and improved air distribution.

Opposed Blade Dampers are widely used in commercial, industrial, and institutional ventilation systems for air volume balancing, airflow adjustment, and system commissioning. They can be installed behind air grilles, inside plenums, or within rectangular duct sections. Depending on project requirements, the damper can be supplied with manual adjustment or optional motorized actuation.

Manufactured from aluminum or galvanized steel, the damper offers durability, corrosion resistance, and long service life, making it suitable for both standard HVAC applications and OEM air distribution assemblies.

Key Features

  • Opposed Blade Configuration  Blades rotate in opposite directions for even airflow modulation and reduced turbulence
  • Precise Airflow Balancing   Suitable for accurate volume adjustment in supply and return air systems
  • Smooth Operation  Linkage mechanism ensures stable blade movement and consistent control
  • Low Noise Performance  Improved airflow pattern helps reduce whistling and pressure-related noise
  • Durable Construction   Available in aluminum or galvanized steel for long-term performance
  • Manual or Motorized Control  Can be operated by hand lever, quadrant handle, or actuator as required
  • Compact Integration   Easy to install behind grilles, diffusers, registers, or inside ductwork
  • Customizable Sizes  Standard and non-standard dimensions available for OEM and project orders

Applications

  • Commercial HVAC systems
  • Office buildings, shopping malls, and hotels
  • Industrial ventilation and air handling systems
  • Supply air and return air balancing
  • Grilles, registers, and diffuser assemblies
  • AHU, FCU, and duct system airflow control
  • HVAC commissioning and air distribution adjustment

Technical Specifications

Parameter Value / Option
Product Name Opposed Blade Damper
Material Aluminum / Galvanized Steel / Stainless Steel optional
Blade Type Opposed multi-blade, counter-rotating
Shape Rectangular / Square
Control Type Manual / Motorized optional
Frame Depth 25 mm – 50 mm or customized
Size Range Standard sizes and custom-made sizes available
Installation Behind grille, inside duct, in plenum box
Finish Mill finish / Powder coated / Anodized optional
Application Air volume control and balancing
OEM / ODM Available

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