Machinery Lubrication magazine published by Noria Corporation
Issue link: http://www.e-digitaleditions.com/i/704613
coolers were examined, none of the thermometers was working. It also appeared that no one was checking the key system parameters, such as temperature, water content, flow, tank levels and cleanliness. When the thermometers were replaced, oil temperatures of 175 degrees F were observed. Evidently, the coolers were having no effect. Once the coolers were replaced, the problem ceased. This was a case of not paying attention to signs that can warn of impending problems. Management hastily instituted a form to be completed on each shift that forced someone to watch those important system parameters. Misreported Oil Demulsibility Oil purchased for the mill's back-up bearing system needed to be able to drop out water quickly. The purchasing specifications gave a very strict number that had to be obtained from the ASTM D-2711 test. ASTM D-1401 is another test for demulsibility, but it is used for light oils. The heavier oils utilized for these back-up bearings had to be tested with the former test, although it took much longer than the ASTM D-1401 test. The mill was experiencing a rise in water levels with samples tested from new loads of oil. Samples taken from in-service oil were having the same problem. Under normal conditions, the water levels should have remained under 5 percent but were now 20 percent. The lab assured the mill that the samples of new oil were within the specifica- tion. This situation continued for several months as an investigation was conducted. There were concerns that back-up losses would soon begin rising. As luck would have it, the lab shut down, which meant the mill had to find another one. When the next sample was sent to the new lab, the mill immediately received a call that the demulsibility was below specification. The load had been pumped out and replaced with a load from another company. It turned out that the old lab had been using the ASTM D-1401 test because it was quicker than the D-2711 test but did not inform the mill. The oil supplier didn't even have the equipment to perform the D-2711 test but was relying on its additive supplier to provide the percentage to use. This was a case of having all the needed tools in place but still getting bad information. Three Phases of Prevention These case studies encompass preventive actions for three types of situations: an obvious situation, a change of methods situation and an unseen situation. Each of these is described below. An Obvious Situation These situations are like the poorly designed hydraulic system or the electric motor bearing issue. The problem is very costly, and the solution is either obvious or requires a design change. The solution will also require time, money and the will to do it. Most agree that solving the problem is worth a try since it is easily seen. These situa- tions are usually designated as "crises." The alternative is to learn to live with the problem. A Change of Methods Situation These situations involve a long-standing way of doing things, such as each department buying lubricants with no attempt at consolidation or not reporting system fluid additions. Although the problems are seen, not everyone envisions a solution or agrees one is needed. Personnel have learned to live with the problem. Basically, the way things are done must be changed. An "Unseen" Situation Many times actions can be taken to prevent bad things from happening. These include condition monitoring, regular inspec- tions, close monitoring of system gauges and oil sampling for laboratory tests. Every plant system has parameters that must be checked periodically. These checks consist of people making an assessment of the condition and filing accurate reports. When these people do their jobs correctly, bad things are prevented. Short-sighted managers only "see" the people who repair things. Those focused on prevention work in a less dramatic envi- ronment. Consequently, when the economy is poor, these jobs often are eliminated. Leaders not only must ensure the "seen" is handled efficiently but also that the "unseen" is not neglected. The "unseen" typically requires recognizing the indications of bad things about to happen, which can often be identified in regular inspections by sight, feel, smell or hearing. However, most of the "unseen" must be detected by equipment. This would include temperature, vibra- tion, sound and lab tests. The "unseen" also involves a conviction that technology can be used to predict events in order to avoid or plan for them. This conviction is an important leadership attribute. Remember, managers don't see the "unseen," but leaders do. 34 July - August 2016 | www.machinerylubrication.com MAINTENANCE AND RELIABILITY