Ductbearing

Ductbearing is a term used in HVAC and mechanical engineering to describe a bearing assembly that supports rotating components within ductwork, most commonly the shaft of an inline fan or blower. The purpose is to provide radial and axial support while maintaining proper alignment between the motor, impeller, and the duct passages. Ductbearings are designed to fit inside or at access points of ducts and may be integrated into fan housings or mounted as dedicated bearing blocks adjacent to the duct wall.

In typical configurations, a ductbearing comprises a bearing element such as a ball bearing or sleeve bearing housed in a rigid support that can be attached to the duct or to the fan frame. Seals or labyrinth seals may be used to limit air leakage and to protect the bearing from dust and moisture. In some systems, the bearing is part of the motor assembly; in others, it is a separate insulated unit with its own lubrication or a dry-lubricated surface.

Materials and types commonly include shielded ball bearings, sleeve bearings, and self-aligning variants, with lubrication options ranging from sealed for life to oil- or grease-lubricated systems. Some designs employ dry or minimally lubricated surfaces to avoid contaminating the airstream, and materials are chosen for temperature and humidity conditions typical of duct environments.

Applications and installation typically cover air handling units, roof- or wall-mounted inline fans, and large-diameter duct runs where long shafts are needed. Proper installation emphasizes alignment, secure mounting, and sealing to prevent air bypass, with accessibility for routine inspection and maintenance.

Maintenance and safety considerations include regular wear inspection, adherence to lubrication schedules when applicable, and checks for corrosion or contamination. Ductbearings should be accessed safely and power isolated during maintenance.