Limitations of Lip Seals
Tests prove that Lip Seals are ineffective protection against bearing housing contamination.
Lip Seals can also seriously wear shafts, causing extensive equipment damage and added cost. When Lip Seals leak, loss of lubrication causes catastrophic bearing and equipment failure. API610 9th edition, Section 5.10.2.7 recognizes this and states that “Lip-type Seals shall not be used”.

Limitations of traditional Labyrinth Seals
Traditional labyrinth seals offer a degree of protection in operation, however, once the equipment stops the bearing chamber cools. The air inside then contracts, sucking moist air past the labyrinth arrangement and back into the bearing chamber. Even the smallest amount of moisture will reduce bearing life dramatically.

Some traditional labyrinth designs have contacting or rubbing elastomers in addition to a labyrinth arrangement. Unfortunately, no matter how sophisticated the design may claim to be, these contacting elastomers wear. This leads to bearing chamber contamination and eventual bearing seizure / equipment failure.