What type of seal is best for protecting fan bearings when handling abrasive materials?

A labyrinth seal is highly effective for protecting fan bearings when handling abrasive materials due to its design, which uses a series of interlocking grooves that create a tortuous path. This structure minimizes the ingress of contaminants, such as dust and abrasive particles, into the bearing housing. As the particles are less likely to reach the bearings, the lifespan of the bearings can be significantly extended even in challenging environments.

Unlike other types of seals, the labyrinth seal does not create a contact with the shaft, which eliminates wear caused by friction. This feature is particularly important when dealing with abrasive materials that could damage seals that make physical contact. The design also allows for some clearance, which can help accommodate thermal expansion and keep the bearings cool, further enhancing reliability in harsh conditions. This makes the labyrinth seal an ideal choice for applications involving abrasive materials.