Industrial Inlet Dampers

Industrial processes and equipment that use centrifugal fans do not usually run continuously. When idle, the fans and machines cool down. In applications where the air temperature is below fan operating temperature, you need inlet dampers to control air flow while the equipment warms up.

Warm up is important because the fan requires more horsepower to cold start than when the air has reached operating temperature. The inlet damper works by throttling the air flow until the machine reaches operating temperature. Allowing for cold start without additional horsepower allows you to apply the appropriate horsepower for your fan and adds flexibility for your operations.

Another reason to specify the inlet-box-damper combination for a given application is to efficiently guide the air into the inlet of the fan. In cases where space constraints restrict the length of the duct entering the fan, the inlet box allows for a 90-degree turn close to the fan inlet to pull the air from any direction.

AirPro’s Inlet Damper Options

We offer three different types. We can customize each one with various materials and construction classes. You can also choose to operate it by either a manual lever or by an actuator and positioner.

Damper Types

Opposed-blade: The most common, least expensive, and least efficient, this type mounts on the outlet of the fan. Most commonly operated by a manual lever.

Parallel-blade: Mounts onto the inlet side of an inlet box. This damper provides pre-spin to air entering the fan inlet. When your application calls for a small operating range, you can use this option as a fan outlet damper as well.

Variable-inlet-vane (VIV): The most efficient and most expensive type, this damper mounts onto the inlet side of the fan. Generally operated by an electric or pneumatic actuator.

Other Useful and Related Information

For more information about Inlet Boxes, view the Accessory description or our blog, Inlet Box: Do You Need One In Your Centrifugal Fan Application?