Cleanroom Air Distribution Systems

Motorized Shut-Off Damper

A compact circular isolation damper whose electric or pneumatic actuator rotates one sealed blade between defined open and closed positions.

Positive Open-Close Operation
Sealed Single Butterfly Blade
Selectable Spring-Return Position
External End-Position Indication

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Product Introduction

The motorized shut-off damper inserts a single circular blade into a short galvanized duct body. A direct-mounted actuator rotates the shaft through approximately ninety degrees to isolate or restore airflow. A perimeter blade seal reduces closed leakage, and the shaft mark provides a mechanical position reference visible outside the duct. Spring-return actuator versions move to the specified open or closed position when power or control pressure is lost, while auxiliary switches can confirm the endpoints.

Key Features

A short round casing fits isolation points where a multiblade rectangular frame would require excessive space.

The single blade and direct shaft connection provide a simple open-close movement with few linkage components.

A compressible perimeter seal restricts leakage around the circular blade in the commanded closed position.

Spring-return and end-switch options support fail-position sequences and remote proof of isolation.

Customer Product Concerns

Reliable shut-off requires the correct fail position, enough actuator torque for seal compression and access to the drive after insulation and ceiling closure.

A modulating damper is used for isolation but never reaches a repeatable sealed endpoint.Defined open-close end stops and a matched actuator focus the mechanism on dependable shut-off travel.

Loss of control power leaves the process branch open.A spring-return actuator moves the blade to the selected normally closed safety position.

Duct insulation hides the shaft mark and actuator release.An extended mounting bracket keeps position indication, wiring and manual override outside the insulation layer.

Excessive differential pressure twists the shaft before the seal seats.Blade diameter, shaft size and actuator torque are selected together for the maximum closed pressure.

Typical Applications

Cleanroom branch shutdownLaboratory exhaust isolationEquipment purge and standby ductsAirlock supply and return isolationSmall process ventilation connections

Technical Parameters

Representative construction ranges for a circular motorized shut-off damper are shown below.

Core Material	Galvanized or stainless-steel circular butterfly blade with elastomer perimeter seal and steel shaft
Panel Thickness	1.0–1.5 mm single shut-off blade
Effective Width	80–630 mm nominal circular duct diameter
Maximum Length	200–500 mm overall casing length in the airflow direction
Steel Facing Thickness	0.8–1.2 mm galvanized or stainless circular casing
Core Density	Approximately 7850 kg/m³ for the steel blade and shaft assembly
Thermal Conductivity	Approximately 45–55 W/(m·K) for galvanized carbon-steel construction
Surface Finish	Mill-galvanized, powder-coated or passivated stainless-steel air path
Joint Type	Round slip-fit or flanged casing with sealed butterfly blade and direct external actuator
Customization	Available based on the intended application and operating environment.

Available Options

Electric or pneumatic actuatorNormally open or normally closed spring returnAuxiliary open-close switchesGalvanized, powder-coated or stainless-steel construction

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