Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1336798
34 | January - February 2021 | www . machinerylubrication.com ENERGY CONSERVATION, HEALTH & ENVIRONMENT because they are intentionally drained by maintenance during oil change procedures. is happens either because of a scheduled oil change as a PM task or because compro- mised conditions of the lubricant have triggered a condition-based oil change. When this happens, the volume of oil is collected in an appropriate waste container which is subsequently disposed of in a larger waste oil storage tank. During this process, the volume of disposed oil should be noted as part of the maintenance activity. is can be estimated by using volume markings on the sides of the disposal container, or any other suitable means. Oil disposal is going to be easier to track, but it is important to note that grease can sometimes be tracked as well. Is the lubricant applied to the machine always the same as the lubricant disposed of? Not always. ere are many reasons for this expected discrepancy. Exploring these reasons and tracking lubricant consumption can be important. In one way or another, the constituents that make up the lubricant end up somewhere. When the lubricant is removed from the machine for unknown reasons, it also removes its ability to provide key lubrication functions and risks lubricant starvation on the equipment. Aside from scheduled oil drains, here are some examples of possible lubricant removal mechanisms that may occur: • Dripped out by gravity from leak points • Pushed out in pressurized systems from seals • Sucked out into product suction lines through seals • Evaporated out by volatilization of oil molecules • Burned out by other hot machine surfaces or microdieseling • Absorbed out by rubber and other elastomeric materials (seals) • Adsorbed out by contaminants and other materials as polar additives and other polar oil molecules hitch a ride when they are trapped and removed by filtration • Foamed out by stable foam generation and escape from a breather port • Splashed out in highly agitated and open top sumps • Extracted out for lubricant sampling • Flung out by high centrifugal force on open-air components (open gears, chains, etc.) • Purged out by maintenance on bottom sediment and waterbowls • Trapped out in closed off pipes and hoses • Spilled out by overfilled systems by maintenance or when contaminants significantly contribute to volume control issues • Siphoned out through pipes, hoses and other absorbent materials • Drained out due to other mainte- nance activities or abnormal events, such as • Sudden component failures • Component replacement • Machines going out of service Some of these lubricant removal mechanisms may be ordinary or seem negligible in volume, but it could still become a root cause for equipment issues. Some of these mechanisms may be highly aberrant and even difficult to quantify in terms of volume for some of the more unique removal mechanisms. Neverthe- less, awareness of these possible events is important and should considered during investigation. In some machines (particularly smaller sumps), every drop is a critical contribu- tion to effective lubrication and when it is lost, it can put the equipment at risk. Tracking the known quantities of lubricant drained becomes an excellent indicator of the unknown and unexpected quantities of lubricant loss. Calculating Lubricant Utili- zation Metrics From a plantwide perspective (as a macro metric), quantifying the total volume purchase or segmented by totals for each lubricant type should be easy. is data can then be compared against either the known volume of lubricant disposed of (to calculate the Lubricant Utiliza- tion Ratio) or the total machine charge in the plant (to calculate the Lubricant Consumption Ratio), all over a fixed time interval, such as yearly. Here is a further explanation of these two ratios. • Lubricant Utilization Ratio is a calcu- lated ratio between the lubricant purchased volume versus the lubricant disposed volume across the plant. If done correctly, this should be a number greater than one. e higher the number, the more oil is going unused or unaccounted for by one or more removal mechanism, including any untracked volumes of oil drained that may have never made it into a machine. A number close to one suggests that most oil applied to machines eventually finds its way to an appropriate disposal container. And while a number less than one is not common, it might be justified, Lubricant Utilization Ratio (Plant)= (Total Lubricant Purchases)/(Total Lubricant Drain) Lubricant Utilization Ratio (Machine) = (Total Lubricant Fill+Top Ups)/(Total Lubricant Drain)