Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/136253
Extending Oil Change Intervals on Heavy Mining Equipment By Piet Hoffman, Kumba Iron Ore, Sishen Mine Extending oil drain intervals in off-highway engines and machines can be challenging. Dirt ingress and coolant leaks occur more frequently, and at times oil drain intervals are established to minimize damage from such problems. The cost reduction associated with longer oil and filter change intervals must be balanced against the risk of shortened engine life and the cost associated with less reliability if oil drain intervals are extended too far. Possible Benefits There are many hidden costs of an oil and filter change that have influenced companies to find a more efficient approach to keep oil healthy and reliable. A recent study found that the true cost of an oil change normally exceeds the oil cost by a factor of 40. These same principles can be applied to filter changes. The following factors contribute to the true cost of an oil change: • Lost production • Paperwork (including maintenance schedules, data entry, manpower planning, inventory management, work orders, documentation, etc.) • Labor and supervision • Storage and handling costs, purchasing and quality assurance (additional costs associated with obtaining lubricants must be taken into consideration, such as lubricant storage and handling, filtering new oil to ensure compliance with specifications, analyzing oil samples, transportation, disposal of used oil, environmental issues, etc.) If It's Not Broken, Don't Fit It Often a lubricant remains serviceable for long periods of time without draining and recharging (influenced by makeup rates, operating temperature, fluid volume, cleanliness, etc.). Draining oil and adding new lubricants into a system presents risks such as: • Introduction of the wrong oil • Introduction of contaminants or contaminated oil • Re-suspension of settled contaminants in the tank/ sump floors and inactive zones • Human agency failures (dead-heading pumps on restart, not opening suction lines, not removing cleaning solvents, loosening machine parts, etc.). Considering the real cost and the associated risk of an oil change, it is wise to let the conditions of the oil drive the decision. Life Factors for In-Service Lubricants There is an assortment of operating conditions that can reduce the life of lubricants and filters. Obviously, if possible, these are to be avoided. However, very often nothing can be done, as many of the factors are associated with the machine's application and environment. www.machinerylubrication.com | May-June 2013 |9