comprise a very thick-walled outer ring
- with three integral flanges
- with a cylindrical outside surface, either relieved towards the side faces or with chamfers
- comprise two inner rings, each with an integral flange
- are sealed on both sides with an FKM O-ring fitted in the inner ring flange groove
- are filled with the high-quality SKF grease LGEV 2 (table 1)
are virtually maintenance-free
However, most of these units can be relubricated via lubrication grooves in the flangeless side faces of the inner rings (fig. 3).
O-rings made of FKM (fluoro rubber) exposed to an open flame or temperatures above 300 °C (570 °F) are a health and environmental hazard! They remain dangerous even after they have cooled.
Read and follow the safety precautions under Seal materials.