NEWS & INFORMATION
Never underestimate the potential for bearing damage from water ...
Research shows it can take less than 0.05% water contamination to substantially shorten the service life of roller bearings. In fact water's destructive effects on bearings can exceed that of particle contamination, with the most severe damage coming from a chain reaction of potential problems:
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Water ingress causing premature oxidation of the base oil.
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Oxides combining with additional water to form a corrosive acidic fluid environment.
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Oxidation creating sludge and increasing oil viscosity, impeding oil flow and damaging the bearing.
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The resulting environment can trap air in the oil, exacerbating lubrication problems even further.
Failure Mechanisms
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Hydrogen Embrittlement or Blistering: Water enters microscopic fatigue cracks in balls and rollers through capillary forces where it breaks down and liberates atomic hydrogen causing further crack propagation and fracture. Sulfur from additives, mineral oils and environmental hydrogen sulfide may accelerate the damage.
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Corrosion: Any water can contribute to rust formation. Corrosion-damaged surfaces on bearing raceways and rolling elements disrupt the formation of critical oil films that control contact fatigue and wear.
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Oxidation: The negative consequences of oil oxidation are numerous but include corrosion, sludge and impaired oil flow.
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Additive Depletion: Water diminishes the performance of additives such as AW, EP, rust inhibitors, dispersants, detergents and demulsifying agents.
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Oil Flow Restrictions: Water absorbs oil impurities such as oxides, dead additives, particles, carbon fines and resin, forming sludge balls and emulsions. These can enter critical oil ways that supply lubrication to bearings potentially starving them of oil.
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Filter Failure: Filters are short-lived in oil systems loaded with suspended sludge.
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Aeration and Foam: It only takes about 0.1% water to create extensive bubbles in bearing sump oil. Air can weaken oil films, increase heat, induce oxidation, cause cavitation and interfere with oil flow - all catastrophic to the bearing.
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Impaired Oil-Film Strength: Roller bearings depend on oil viscosity to create a critical clearance under load. Small amounts of water in the load zone may critically reduce this clearance, resulting in friction and wear.
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Microbial Contamination: Water promotes microorganisms such as fungi and bacteria that can form thick biomass suspensions over time, plugging filters and interfering with oil flow. Microbial contamination is also corrosive.
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Water Washing: When grease is contaminated with water, it can soften and flow out of the bearing. Pressurized water sprays can also wash the grease directly from the bearing and force water in.
The obvious answer to the problem of water ingress in bearings is to prevent it ever happening, as the cost of remediation and replacement will always exceed that of protection. Enviropeel has proven, time and again, to be the most effective and cost-efficient solution for bearing protection in the wettest and most contaminated environments.
Below: it's easy to see how water-jetting could affect this bearing without Enviropeel protection
Information on bearing failure mechanisms is based on an article by Jim Fitch of the Noria Corporation: How Water Causes Bearing Failure
