Bearing Isolators0 pages

Bearing Isolators – Meeting Tough Demands!
Earl Rogalski
Marketing Manager
Garlock Klozure®
an EnPro Industries company
1666 Division Street
Palmyra, NY 14522
Tel.: 315-597-3362
Fax: 866-645-7325
earl.rogalski@garlock.com
www.klozure.com | www.splitisolator.com | www.splitoilseal.com

Introduction
Dynamic sealing technology has continued to advance in recent years, changing from off-the-shelf radial lip seal commodities to hightech engineered products. As asset uptime and governmental requirements become more and more demanding, the need for high
quality engineered sealing solutions increases.
Seal design advances include contact lip seals and non-contact labyrinth seals. For labyrinth seals, commonly known as Bearing
Isolators, the intricate path and advanced design features are important factors to ensure consistent and reliable sealing.
Understanding all of these factors will allow the user to make intelligent seal choices that will impact equipment life, productivity, and
total maintenance costs.

Understanding labyrinth seals and available technology
Unlike elastomeric radial lip seals labyrinth seals are relatively simple in theory. In standard designs, a labyrinth seal is nothing more
than an intricate pathway with abrupt directional changes (see Figure 1). The intricate directional change creates a barrier which
prevents ingress or egress of material; application lubrication, external fluids or airborne contamination. However, new labyrinth
seals, commonly referred to as hybrid labyrinths, are becoming popular. Hybrid labyrinth seals are essentially a combination of new
sealing technologies with standard labyrinth technology. These new technologies consist of unique unitizing elements, hydrodynamic
pumping features, cellular foams and/or liquid o-ring seals. Hybrid labyrinth seals are typically chosen for technically challenging
applications when standard labyrinth technology just won’t work.

Stator

Labyrinth Path

Rotor

Figure 1 Labyrinth bearing isolator
Figure 2 represents a hybrid labyrinth which uses a unitizing element to keep the assembly together while maintaining appropriate
internal clearances. A common misnomer is that the unitizing element creates a seal barrier, but this is just not the case. The unitizing
element simply prevents the rotor and stator from coming into contact with one another during operation, which prevents the
potentially harmful generation of metallic particulates. If contact between the rotor and stator were made during dynamic operation,
the particulates generated would then contaminate the lubrication system and eventually lead to premature bearing failure, both of
which are costly endeavors.

Stator

Labyrinth Path

Unitizing Element
Rotor

Figure 2 Hybrid labyrinth bearing isolator with unitizing ring
1