Cleanroom Air Distribution Systems

Airtight Shut-Off Damper

An aluminum multileaf damper with closed-cell edge seals and enclosed gears for extremely low-leakage isolation of rectangular ducts or wall openings.

Extremely Low-Leakage Closure
Sealed Aluminum Airfoil Blades
Closed-Cell Jamb Seals
Enclosed Synchronized Gears

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Product Introduction

The airtight shut-off damper is built from extruded aluminum casing sections and opposed hollow airfoil blades. Replaceable tip seals meet at each blade edge, while closed-cell side seals close the gaps at the jambs. Enclosed gears rotate every blade together and remain protected from the primary airflow. The rigid rectangular frame can be fitted into a duct, wall opening or ceiling slab opening and operated manually, pneumatically or by an electric actuator.

Key Features

Opposed aerofoil blades close onto continuous tip seals to restrict leakage across the complete face.

Closed-cell jamb seals compress at the blade ends without exposing fibrous material to the air path.

Encased gears maintain blade timing and protect the synchronization mechanism from dirt and contact.

Extruded aluminum construction provides a smooth corrosion-resistant surface for hygiene-sensitive ventilation.

Customer Product Concerns

Low-leakage isolation depends on even frame geometry, continuous seal compression and enough closing torque to overcome pressure and seal friction.

Frame distortion during duct installation prevents the outer blades from reaching their seals.A rigid installation subframe and square fixing pattern preserve jamb spacing and blade alignment.

Side gaps dominate leakage even when the blade tips appear fully closed.Continuous closed-cell jamb seals close the blade-end clearance along both sides of the frame.

Exposed linkage collects dust and becomes difficult to clean.The synchronization gears are enclosed within the frame profile and separated from the main airway.

The actuator reaches its stop before all seals are uniformly compressed.Correct torque, end-stop adjustment and synchronized opposed blades distribute closing force across the face.

Typical Applications

Cleanroom duct isolationPharmaceutical HVAC shutdown zonesLaboratory supply and exhaust branchesAirlock pressure-system isolationLow-leakage wall or ceiling openings

Technical Parameters

Typical construction data for an aluminum extremely low-leakage multileaf damper are listed below.

Core Material	Extruded aluminum hollow airfoil blades with PE or TPE tip seals and closed-cell EVA jamb seals
Panel Thickness	20–35 mm extruded hollow blade depth
Effective Width	200–1200 mm nominal frame width
Maximum Length	Up to 1000 mm nominal frame height
Steel Facing Thickness	1.0–1.5 mm galvanized shaft plates, drive arm and linkage components
Core Density	Approximately 2700 kg/m³ for the extruded aluminum sections
Thermal Conductivity	Approximately 160–205 W/(m·K) for aluminum blades and casing
Surface Finish	Natural anodized aluminum or powder-coated RAL finish with closed-cell seals
Joint Type	Flanged rectangular frame with geared opposed blades, compressible tip seals and continuous jamb seals
Customization	Available based on the intended application and operating environment.

Available Options

Manual quadrant or electric actuatorSpring-return normally open or normally closed driveNatural anodized or powder-coated finishIntermediate frame sizes and installation subframe

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