Bearings are precision components; they time require clean lubricants in adequate amounts to survive, and even seemingly small amounts of contamination can greatly Reduce equipment reliability and uptime. A new generation of bearing protectors is now available That can help maintain lubricant cleanliness, Prevent loss of lubricants, and Prolong the life of your rotating equipment.
Where Contaminants Come From
Moisture and dust enter Often bearing housing
Moisture and dust enter Often carrier roller (Fig. 1) through old-style labyrinth seals or lip seals as airborne water vapor, or via a stream of water from hose-down operations. Contaminants can enter through Also a breather vent, or from the Widely used non-pressure balanced lubrication constant level (Fig. 2 and Ref.1). An Often-Overlooked source of oil contamination is abraded oil ring material, Which will be discussed later in this article.
Widely used non-pressure balanced constant level lubrication
How to Stop the Contamination
Unless the rotating equipment is provided with Suitable carrier roller manufacturers seals, an interchange of internal and external air (called "breathing") takes place during alternating periods of operation and shutdown. Bearing housings "breathe of" because rising temperatures during operation cause gas volume expansion, and dropping temperatures at night or on shutdown cause gas volume contraction (Ref. 2). Open or inadequately sealed bearing housings with the promote this back-and-forth movement of moisture-laden, contaminated air.
To stop this breathing and Resulting contamination, there shouldnt be no interchange between the housing interior air and the Surrounding ambient air. Breather vents (Fig. 1) shouldnt be removed and plugged.
Instead of the Widely-used (non-pressure-balanced) constant level lubrication (Fig. 2), Which allow the oil to come in contact with dirty air, a pressure-compensated (or "balanced") constant level lubricator shouldnt be installed ( Figs. 3 and Ref. 3). Both devices will be explained more fully a bit later.
pressure balanced constant level lubricator
Finally, full sealing of the bearing housing requires the use of face seals. . An API-610 compliant magnetically-activated dual-face seal used is oil mist-lubricated rolling element bearings is show in Figure 4; a similar device is used to seal conventional oil-splash lubricated bearings. The use of a face seal, along with the other recommendations above (plugging the vent and using balanced Oilers), will Prevent the entry of all EXTERNAL contamination into the housing.