Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1171112
36 | September - October 2019 | www . machinerylubrication.com Lubrication's biggest enemy is contamina- tion, especially solid conta mina nts like dirt. Once contamination gets into the oil, it becomes a crux to lubri- cant failure and ultimately machine failure. A robust reliability program would not be complete without an action plan to help minimize contamination in lubricants. While all lubricated machines are prone to the pitfalls of contam- ination, hydraulic systems are of particular interest, as they experi- ence unique operating conditions and often require components that are inherently contaminant- sensitive. How contaminants aff ect the reliability of hydraulic systems has been the focus of hundreds of studies over the last few decades. For a brief history of E.C. Fitch's crucial involvement in understanding the inf luence of contamination on hydraulic systems, see the sidebar on the next page. Today, hydraulic system manu- facturers and end users are more aware of the contaminant sensi- tivities of machine components. However, while the "why" has been expressed and openly discussed, the "how" is not as widely understood. is not only would include how to reduce contaminants in the system but also by how much. In hydrau lic systems, t he proactive measures of fl uid contami- nation control — both exclusion and removal of contaminants — require an investment beyond just the equipment. Typically, an optimized approach includes a combination of both. With exclusion being the fi rst line of defense, it almost always is more cost eff ective to keep contam- inants out rather than to remove them after they are in the oil. It has been estimated that it costs at least 10 times more to remove a gram of dirt than it would to exclude it in the fi rst place. One principle to consider is the optimum reference state (ORS), where each lubrication decision strives for optimization by consid- ering all relevant factors, such as cost, safety, downtime, component sensitivity, etc. is principle can be applied in the context of contam- ination control as well. On one extreme, you could get carried away by investing excessively in fi ltration practices to ensure the machines are kept clean. On the other end, you Determining the Required Cleanliness Level of Hydraulic Systems Creating a required cleanliness level (RCL) target is only the fi rst step of a complete proactive maintenance contamination control strategy." " Hydraulic s LESSONS IN LUBRICATION Bennett Fitch | Noria Corporation