Water Induced Bearing Fatigue in Paper Machine Applications: Monitoring and Solutions, 1997 Engineering Conference Proceedings
Water plays a vital role in virtually all paper manufacturing processes. It is a well recognized fact that the intrusion of water into paper mill equipment and their lubrication systems is virtually impossible to eliminate. The close proximity of liquid water, ambient water mists and sprays, and steam to operating mechanical systems, reservoirs and other components provides ample opportunity for water to enter lubricating systems.
The detrimental effects of water on bearing and gear performance has been well documented. Excessive water can create emulsions in oil that form deposits and further reduce lubrication effectiveness. Chemicals in various types of mill waters, such as water-based cleaners, and steam carrying boiler feedwater chemicals, further compounds the problem.
In addition, the high speed, high pressure and high temperature production systems create conditions which significantly accelerate the damaging effects of water contamination on bearings and gears in both new and rebuilt units.
The paper industry has taken extreme measures to reduce the levels of water in the more critical equipment, such as dryer centralized lube systems, press sections, calender systems and crown roll systems. If unscheduled failures occur, downtime results in lost revenues that can range from $10,000 to $30,000 per hour in lost production.
Fortunately, due to the paper industry’s advanced preventive maintenance programs and high technology monitoring programs, the vast majority of the failures can be predicted and repaired at a scheduled outage.
Is there a way to reduce unplanned failures (predicted as well as catastrophic) and increase the life of the critical equipment in the paper mill? The answer is “yes”, of course, but sometimes the cost effectiveness of incremental improvements to keep the water out in the first place and/or to remove it before it can do harm may not justify their implementation....