Today’s Gremlin – “lube it wrong”, is a leading cause of machinery breakdown. 60% to 80% of all bearing failures are due to lubrication related problems. Wrong lube, too much lube, too little lube, contaminated lube, degraded lube, overheated lube and even poor lube selection can all lead to premature failures of bearings. Put a tiny bit of dirt into a hydraulic system and watch it fail quickly.
Lubrication is the life blood of machinery and mechanical systems. The space between moving parts is usually very small and called, “clearance”. Lubricants provide a small film between moving parts to keep them from overheating and wearing out. Hydraulic systems use oil to transfer power in components that usually carry a lot of load and have very tight clearances to prevent internal leakage. Those tight clearances keep hydraulic systems efficient. Dirt in those clearances causes leakage, loss of power and overheating, allowing a small problem to grow.
Even dust and smoke particles are often larger than those clearances so when they get into machinery dirt particles can act like cutting tools. They damage moving surfaces, cutting grooves that increase leakage. Incorrect lubrication increases friction and causes a lot of “parasitic” energy loss. The US Department of Energy estimates that up to 20% of energy consumed is actually wasted through parasitic losses. In addition to saving on maintenance costs, that’s a huge potential cost saving in most operations.
“Lube it wrong” is one of the many gremlins we referred to when we introduced this series of articles.
Too much and too little
The volume of lubricant in any system is designed to achieve a balance of lubrication and cooling of the oil. If we add too much lubricant we don’t allow it to settle in sumps and the moving machinery stirs it up, causing it to mix with air and foam. Foam inhibits heat transfer, it can’t be pumped, and it won’t lubricate as well as liquid. If we have too little lubricant, it won’t have enough time to cool, will overheat and degrades quickly. If there’s not enough to fill the lubricant channels then it won’t get to where it is needed. The machinery will be under-lubricated, will overheat, can expand and reduce clearances, eventually failing.
Wrong lubricant
Lubricants are chosen to reduce friction between parts, cool them, and last a long time. The wrong lubricant can have the wrong viscosity (thickness) and provide too little, or too much friction. A gear oil in many bearings will be too thick to lubricate properly. Put bearing oil in gears allow too much gear tooth wear. Wrong lubricants can have insufficient heat transfer properties, or it can simply degrade too quickly. As lubricants heat up they get less viscous (less thick) so friction between parts can increase.
Insufficient cooling
Heat transfer (cooling) takes time. Too little oil will circulate too quickly and stay hotter providing less lubrication and less cooling of parts. It will gradually overheat, degrade and both the lubricant and the machinery can suffer. Not only do we need to pay attention to the oil itself, but also how it is cooled. The sump where the oil is stored must be clean so it can radiate heat. Liquid to liquid coolers must have coolant flow. If the lubricant is air cooled the cooling fins must be kept clean and airflow unrestricted.
Contamination
Compared with the clearances in some machinery, especially in hydraulics, dirt is “big”. Sand, dirt, dust, grit and even smoke particles can be larger than machinery clearances. Water reduces lubrications properties and increases tendency to foam dramatically. Even oil from a new barrel that just arrived from a refinery will have both moisture and dirt that exceed some machinery specifications. It needs to be both dehydrated and filtered. I once worked at chemical plant associated with a refinery that produced lubricants. We got our oils from that refinery and it was never good enough “as is” without being treated first.
Storage and handling of lubricants, oils and greases, is often overlooked. Lubricants bought in bulk need to be treated before we use them because they come to us contaminated. Allowing them to be exposed to the atmosphere in most industrial operations, exposes them to contaminants and humidity. Storing them in dirty sheds or outside invites opportunities for contamination. Transferring grease and oil in open containers invites contamination. Pouring oil in through open necked fillers and funnels from open containers invariably adds contaminants.
Dirt in systems
Dirt inside new piping, new hydraulic hoses, or machinery that is opened up in the plant, can all be problematic. In one operation they performed gearbox inspections in the plant which had a dusty atmosphere. They followed manufacturers recommendations, but the gearboxes never lasted long and they wondered “why?” Another operation fabricated their own hydraulic hoses, failed to flush them properly and then stored them without capping the ends. They suffered a lot of hydraulic failures in their mobile equipment and a lot of downtime as a result. failed long before “their time”.
Most of these problems are avoidable
Lack of attention to lubrication is a huge problem in industry. It’s not enough to just check levels, top things up, or give it a few shots of grease periodically. The right lube, pristine lube, the right quantity, the right handling, the right conditions, and the right cooling all matter. Don’t assume your mechanics know lubrication – it is a specialized field and every industrial operation should have qualified lubrication technicians, and a properly designed lubrication program.
If your operators do some of the lubrication tasks, they need to be trained, not just showed how to do it. Untrained people make a lot of mistakes and it’s not their fault – they are usually trying to do the right thing, but they simply don’t know what they don’t know.
Today’s Gremlin, “Lube it wrong”, causes far more trouble than you may realize and deserves your attention. We can help with training and development of lubrication programs that will dramatically reduce lube related breakdowns and energy consumption.
