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 |




