Continued from page 10
This recording shows the bearing dB & amplitude increase as more lube is added and has reached the threshold of over lubrication.
Drive bearing lube history:
Generally speaking, when the amplitude of a bearing exceeds 8 dB and there is no difference in the sound quality established at baseline, the bearing needs to be lubricated. To prevent potentially disastrous over-lubrication, the technician will then apply lubrication, a little at a time, until the dB level drops. Many departments set up their “condition-based” lubrication programs by incorporating a two-stage approach. The reliability inspector uses a relatively sophisticated ultrasound instrument to monitor and trend bearings. A report of bearings in need of lubrication is produced. The lube tech then uses a specialized ultrasound instrument that alerts the tech when to stop adding grease. These instruments can be affixed to a regular grease gun or worn in a holster.
To improve efficiencies, it is a good practice for the technician to note when the equipment was last greased and how much grease was used to calculate roughly how much lubrication is used per week. By using ultrasound to lubricate each and every time, the technician produces a historical data that can be used as a guide from previous calculations, helping the department to determine whether the lubrication schedule can be modified, perhaps saving man-hours, and whether the manufacturer’s suggested lubrication amount is accurate (if less is needed, there’s cost-savings potential).
This chart shows a trend of decibel readings taken on a drive bearing. The readings are plotted against a baseline dB, a low alarm dB and a more critical high alarm dB.
Ultrasound technology has many advantages:
• It can be used in virtually any environment; • Learning to use ultrasound technology is relatively easy; • The technology is relatively inexpensive; • Modern ultrasonic equipment makes it easy to track trends and store historical data;
• Ultrasonic technology has proven itself to be extremely reliable in predictive maintenance, saving thousands upon thousands of dollars and hours of lost productivity.
How ultrasound produces better lubrication practices Ultrasonic technology helps the lubrication technician take a lot of the guesswork out of lubrication needs. Ultrasound is a localized signal meaning when a sensing probe is applied to a bearing, it will not be affected by “crosstalk” and allows the technician to hear and monitor the condition of each individual bearing. Ultrasound looks at each individually, much the same way medical ultrasound can detect exactly which artery is clogged or which vein is leaking.
As an example of ultrasound’s efficacy, consider this: a maintenance manager at a large firm reports that, since adopting ultrasound technology and practicing ultrasound- assisted, condition-based monitoring rather than “running to put out the fire”, his plant has gone from close to 30 rotating equipment failures per year to zero in three years. But how does ultrasound work, exactly, vis-à-vis lubrication?
The first step is establishing both a baseline decibel level and a sound sample. This is ideally done when moving through a route for the first time by first comparing dB levels and sound qualities of similar bearings. Anomalies will be easily identified. Once established, each bearing can be trended over time for any changes in either amplitude or sound quality.
12
And while most of this discussion has focused on the dangers of under and over-lubrication, ultrasound is just as reliable in picking up other potential bearing failure conditions. The technician, using ultrasound, can hear telltale “grinding” sounds and other anomalies, which are often accompanied by an amplitude increase. With regards to lubrication, the advantage of ultrasound is that it is able to isolate bearings and determine their individual needs, thus reducing the possibilities that some bearings are too “dry” and prevent others from over-lubrication.
Why you should begin using ultrasound – today! It is always a daunting proposition to make a new investment in technology. Will it pay off? Will my staff actually have an easy time using it? Is it a flash in the pan or a truly reliable modality that will stand the test of time?
While more and more plants are using ultrasound and adopting a predictive and proactive rather than reactive mindset, there are still many that are figuratively using crystal balls and outdated methodologies. The end result is poor reliability, unnecessary man-hours, downtime and lost productivity and profit. While ultrasound can’t cure all reliability ills, it has proven itself – in a plethora of settings – to be a valuable and powerful diagnostic tool that technicians must add to their toolkit.
When it comes to something as important to reliability as lubrication, the question really becomes: “Can you afford not to use ultrasound technology?” Consider the plant that went from close to 30 bearing failures a year before using ultrasound to having no bearing failures for three years once bringing ultrasound into its maintenance arsenal. It’s no coincidence. Ultrasound works.
For more information on ultrasound technology and to access valuable resources, including a sound library, presentations and articles, visit UE Systems’ website at
www.uesystems.eu.
LINK
www.uesystems.eu
LUBE MAGAZINE NO.133 JUNE 2016
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53
