Accessories and Modifications

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While each of our fans comes with an Installation and Maintenance guide, there are several accessories and modifications that can make operating and servicing a fan easier. The benefits to using these include increased reliability and performance, decreased downtime and the ability to assess irregularities and determine the cause easier and faster.

To find maintenance information for your specific fan, visit the Installation & Maintenance page. If you have questions about any of these accessories, or how they could help improve fan performance or make maintenance easier, please contact your local representative.

Common Accessories

Accelerometers are used to monitor fan vibration levels and alert plant personnel of excessive vibration. Vibration is a common cause of premature impeller and bearing failure. Early detection of changes to vibration levels allows for proactive troubleshooting and maintenance, decreasing the likelihood of equipment failure. Accelerometers are typically installed on bearing housings.


Flexible connectors, also referred to as expansion joints, isolate a fan‘s inlet and/or outlet flange from connecting ductwork. This isolation helps lessen vibration transmitted between the fan and system and compensate for misalignment between the fan and connecting ductwork. nyb offers a wide variety of flexible connector construction options allowing for optimal design based on a system’s gas-stream composition, velocity, and temperature. These are available in a circular or rectangular designs.
Reference: Flex Connectors

 Flexible ConnectorsFlexible Connector 2

Bearing RTD’s (Resistance Temperature Detectors) are used to monitor bearing temperatures. Bearing temperature is a key indicator of bearing health. Identifying temperature increases at the time they occur allows plant maintenance personnel to address potential issues before costly damage is done to bearings. RTD’s are typically compact, and install directly on bearings.


Flow meters can be used to measure air velocity, air volume and temperature to better understand performance metrics or how performance changes based on different operating conditions.

Flow meter

Properly designed inlet boxes offer predictable entry losses associated with a 90° turn at the fan inlet. These entry losses are accounted for during the fan sizing process. Inlet boxes are also used on fan arrangements with a center-hung impeller (arrangements 3 & 7) to isolate the bearings from an airstream that may be high in temperature, or laden with contaminates. Common inlet box accessories include drains, bolted cleanout doors, and parallel-blade dampers.
Reference: Inlet Boxes and Inlet Box Dampers

 Inlet box

Parallel-blade inlet box dampers control airflow by spinning air entering the fan in the same direction as the impeller rotation. Controlling airflow by means of an inlet box damper offers greater efficiency than flow control by means of an outlet damper. These dampers are offered with options for manual or actuator-controlled modulation.
Reference: Inlet Boxes and Inlet Box Dampers

Inlet box dampers

Inlet filter assemblies for Pressure Blowers and HP Pressure Blowers are designed for greater airflow and efficiency than the typical inlet filter. These are available for most sizes, with option filter-silencer assemblies, with and without hoods.
In addition, replacement filter elements can be ordered online. Contact your local sales representative if you do not have a file number or have questions about replacements.
ReferenceDimensions for PB/HPPB Inlet Filter Assemblies
ReferenceDimensions for Compact GI Inlet Filter Assemblies

Inlet box dampers

Motor disconnect switches are an easy way to ensure the motor is de-energized, and can be used when maintenance or service work needs to be performed. It can allow for the fan to be turned off while energy is still supplied to other components surrounding the unit.

 Motor Disconnect Switch

Outlet dampers work on the principle of adding resistance to airflow. They are available in parallel, butterfly, and opposed blade construction to best suit dampering requirements. There is removable linkage and removable casing side to allow replacement of bearings and vanes. The stuffing-box option is also available for minimal leakage through casing.
Reference: Outlet dampers for centrifugal fans

 Outlet damperOutlet damper 2

Belt guards, shaft and bearing guards, coupling guards, inlet guards, and outlet guards are available. Guards can offer protection from all exposed moving parts and high-velocity airstreams.
One of the main advantages to ordering guards is increased workers' safety. Guards may also be used to adhere to federal and state laws/guidelines, including OSHA requirements. All guards are constructed in-house, and can be customized to the customers' specifications.

Reference: Safety Equipment: Guards

 Safety equipmentSafety equipment 2

Silencers have been designed for mounting on the inlet or outlet of the fan, but may also be used elsewhere in the duct to decrease the sound levels. They are available for rectangular or circular discharge for both centrifugal and axial fans.
Reference: Round Inlet and Outlet Silencers/Optional Transitions for Fans
ReferencePressure Blower & HP Pressure Blower Silencers

 SilencerSilencer 2

Two standard types of variable inlet vane dampers are available. Both operate on the same principal of pre-spinning air entering the fan inlet, allowing for efficient control of fan performance. Internal inlet-vane dampers are integral to the fan inlet cone. They are a compact, low cost solution for less demanding applications. Quick-opening cleanout doors are typically furnished to provide easy access to linkage components.

External variable inlet vane dampers typically bolt to the fan inlet flange. They are of more robust construction than internal inlet vane dampers, allowing for use in demanding applications. These dampers are offered with options for manual or actuator-controlled modulation.

 Variable Inlet Vane Dampers

Issues with vibration can be properly managed through additional accessories. Vibration switches are designed for monitoring bearing vibration for early detection of a problem that might lead to potential bearing failure. Unitary bases, rubber-in-shear and spring isolation can also be used to help reduce or limit vibration transference from the fan to the supporting structure.

 Vibration IsolationVibration Control 2



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