Machinery Lubrication

Machinery Lubrication November December 2014

Machinery Lubrication magazine published by Noria Corporation

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44 | November - December 2014 | www.machinerylubrication.com IN THE TRENCHES We s ca sh | Nori a Corpor at ioN article contamination is known to cause countless machine failures. One of the best tools to measure and understand this root cause is particle counting. Few facil- ities utilize the power of this test to its full potential and instead just look at the counts as a way to gauge oil cleanliness. By under- standing what the particle counter is telling you and employing proper sampling locations, you can make better use of the infor- mation in your oil samples. One of the most basic forms of proactive maintenance in a lubrication program involves setting target cleanliness levels for different machine types. More often than not, the ISO 4406:99 particle count levels are used for this objective. While this may offer a quick classification of the oil's cleanliness, you should delve deeper into the numbers to see what truly is occurring. The ISO standard looks at three different particle size ranges: 4, 6 and 14 microns. However, most particle counters can provide information for several more sizes, sometimes up to 100 microns. These counts are then compared to the Renard series table to establish standard particle count values such as 18/16/12. Although it is a good practice to set goals and targets based upon these numbers, if your focus is only on the ISO code, you may fail to consider the results from the particle counter. Generally, for every increase in the ISO code, the amount of particles in the oil sample doubles. However, since the chart is arranged as a series, there may be as few as one more particle that raises the ISO code or as many as four times the number of particles. Therefore, it isn't always sufficient to use this number to drive your actions. Knowing the individual particle counts and from where the oil sample was extracted will be essential for your oil analysis program. When a report comes back from the lab, it is easy to look at the ISO code and determine a course of action. However, if you examine the individual counts, you can begin to gauge whether the actions you are taking to achieve your cleanliness targets are effective. For example, say you have a system that is decontaminated with a portable filter cart. The goal is to clean the system to an ISO code of 18/16/13. Your reports continue to show a higher ISO code of 19/17/14. Normally, you might think the oil is still dirty and that you should continue filtering, but upon checking the individual particle counts, you see that you are only a single particle away from achieving the goal. With another quick round of filtering, you can reach your target. Monitoring individual particle sizes can provide other important information. For instance, take the case of filter performance. A number of filters on the market are touted as 3-micron filters, but not all of them have the same efficiency for capturing particles at that 3-micron size. This is commonly referred to as the filter's beta rating or beta ratio. By using a particle counter and taking samples before and after the filter, you can look at the individual particle counts to help determine the filter's true efficiency and micron values. This practice can also help you select filters for specific machines and understand a filter's life expectancy. If you analyze particle counts before and after the filter, you can evaluate whether the filter is deteriorating in service. The farther apart the particle counts, the better the filter is performing. The closer the numbers are, the worse the filter is functioning. P a r t i c l e C o u n t i n g The benefits of particle counters are truly limitless as long as you are conscious of what you are doing and understand the results. How to Get the MOST from Your PARTICLE COUNTER P 4 µm 6 µm 14 µm ISO Code 1,301 321 41 18/16/13 2,500 640 80 18/16/13 2,501 641 81 19/17/14 5,000 1,300 160 19/17/14 one more particle 4X as many particles

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