Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/258778
As I see It 2 | January - February 2014 | www.machinerylubrication.com Early detection means frequent detection. While daily one-minute visual inspections have been discussed previously in Machinery Lubrication magazine, many questions remain, including where and how you inspect, what the observed conditions mean, and how you penetrate a machine's exoskeleton exterior without X-ray vision. There are three important inspection zones in common oil reservoirs and sumps. These zones have a story to tell about your oil and machine. They might be difficult to reach, but difficult does not mean impos- sible and certainly doesn't mean unnecessary. Let's get inside that exoskel- eton and see what we need to know. Level, Foam and Deposits (LF&D) Zone Machines don't just need some lubricant or any lubricant. Rather, they need a sustained and adequate supply of the right lubricant. Adequate doesn't just mean dampness or the nearby presence of lubri- cant. What's defined as adequate varies somewhat from machine to machine but is critical nonetheless. High-speed equipment running at full hydrodynamic film has the greatest lubricant appetite and is also the most punished when starved. Machines running at low speeds and loads are more forgiving when lube supply is restricted. Even these machines can fail suddenly when severe starvation occurs. There are four keys to solving starvation problems using proactive maintenance: 1. Identify the required lube supply or level to optimize reliability. 2. Establish and deploy a means to sustain the optimized supply or level. 3. Establish a monitoring program to verify that the optimized supply or level is consistently achieved. 4. Rapidly remedy non-compliant lube supply or level problems. For non-circulating wet-sump machines, slight changes in oil level can be cata- strophic. These include bath, splash, oil-ring, flinger/slinger and similar lubricant supply methods originating from an oil sump. For these machines, frequent confir- mation that the correct oil level is maintained has everything to do with machine reliability. This is best done by properly mounted and frequently inspected level gauges. Some things float, and other things sink. What floats is lighter than oil. It rises by buoyancy. For instance, certain low-density additives can rise and form a visible film on the oil's surface. Air bubbles, water vapor, natural gas and refrigerants are all buoyant. Once they get to the oil's surface, they either release gases into the atmosphere or create bubbles. A stable layer of bubbles forms foam. Foam is disruptive for a variety of reasons, but most importantly it is associ- ated with lubricant starvation. For more information on the causes and remedies of aeration and foam, see http://www.machin- erylubrication.com/Read/690/aerated-oil. Aeration and foam can be detected as long as you have a window. Sight glasses and level gauges mounted in ports that are centerline to the oil level enable this and should be included in a daily inspection program. This allows both oil level and Use zoNe Inspections for eArly ProBlem detection o i l A n a l y s i s JIm FItCh NorIA CorPorAtIoN of lubrication professionals conduct daily visual inspec- tions of the oil at their plant, according to a recent survey at machinerylubrication.com 70% Figure 1. An advanced case of deposits accumulating on metal surfaces above the oil level