Acoustic Emmisions

Hi scott.r111

Our steel mills used the vibration analysis technique on some very high dollar rate equipment.

I was a pup at the time and sadly have not much to contribute in this area.

However, I have personal experience with using infra red thermometers and oil analysis to determine predictive failures at a lower cost cold finish mill.

Surveying all high horsepower equipment bearings after two hours run time each Tuesday allowed us to identify vulnerable bearings by temperature and change versus trend of other bearings- which we would target next maintenance turn. We reduced unplanned downtime SIGNIFICANTLY with this and a few other techniques.

Sorry we couldn't give you a boost on the acoustics.

We are familiar with tool monitoring which relies on an acoustic technique. let us know if you are interested in that.

milo

Thanks Milo,

We have also started an oil analysis regime and infra red thermometers, so it's good to hear you had some success with these.

Hopefully with the different methods we are utilising we should see failures coming. Bearings for wind turbine gear boxes are like gold dust at the moment! If we can order in advance then it is a huge benefit. We have such a varied range of plant that it is difficult to hold stock.

Thanks again for your input,

Cheers

Scott

Just a quick question on this so I can answer correctly. Are you asking about ultrasonic testing on bearing in motors and other friction points? If so You can also use this to check for steam leaks and for compressed air. Sounds as though you are starting a PM program. Perhaps predictive or even reliability centered maintenance. I have been doing this for a few years, let me know if I can help.

Hi Logix101,

Yes we (I) am starting PM program, hopefully predictive.

The kit I will be using is geared up for listening to friction/noise in bearings and the like, we are going to buy an addition that allows us to listen and have a reading for contactor chatter (this is a new development by the manufacturer). The manufacturer is a UK company called Holroyd Instruments. The instrument gives you two readings, Distress and the db level, this allows for trending. You can also capture specta for analysis with the software, although you need all the usual info like bearing size/rolling elements etc. Hopefully it's been a good purchase.

We have also started collecting oil samples for analysis twice a year + temp readings.

We are also buying a videoscope for inspection of our gearboxes. All have a planetary stage that you cannot see without.

All this is for wind turbines, which are relatively simple pieces of kit. They are however left in production without inspection for extended periods. My aim is to visit each turbine semi annually (25 units at the moment, but more on the way).

Any help or advice you can give will be gratefully received.

All the best,

Scott Ridley

I do admire a good start up of PM, I hope you have the reliable people in place to perform your testing and management in place to support the program. If you wish you can contact me in the private mail box on this forum and I will provide contact info and we can help you hit the ground running. I will do my best to help.

Thank you, I'd really appreciate it!

ASNT, The American Society for Nondestructive Testing, provides certification in Vibration Analysis, Ultrasonic Testing, Acoustic Emission Testing, etc. etc.

Visit the following page, and click on the link to: "Classification of NDT Methods"

there's more to learn than you can possible imagine...!

It's amazing how many companies can be convinced to spend enormous quantities of dollars on high-tech equipment for testing purposes, because "somebody" in said company heard that this "such-and-such" (particular tool) was the "Cat's Meow" when it came to accomplishing what they wanted to achieve... and yet, they refuse to exhibit the foresight to insure that SOMEBODY in the company is going to be qualified to USE it properly! [This is more often than not done AFTER the fact, of purchase.]

Each new application of these newer technologies requires a Learning Curve, in order to optimize the testing and interpretation of results. The less you know to begin with, the steeper will be the curve.

Translation: just because company "A" has done the R&D for testing a certain 6-cyl diesel engine doesn't mean that the technology is perfected for testing aircraft engines, OR synchronous electrical machinery, OR turbines in a reactor-generating station, etc. etc. ... and viceee-verseee.

You may very well be blazing a new trail with your particular application here. I do wish you the best ~

GA.

milo

Thanks ndt-tom. I was just getting to the buy more than you need speech. now more than ever, at start up is a critical time . It is easy to be convinced of what to have to have. It is best practice to start with critical and work your way down from there.

Standard vibration analysis has a long and proven history, and should be a part of your program. Acoustic emissions has a shorter history, and more than a few "snake oil" salesmen. The idea with acoustic emissions, is that particularly for greased bearings, the acoustic emissions data will tell you when your lubrication is insufficient so that you can go re-grease. The problem is in relating acoustic emissions to actual bearing failures. That is a bit of art, and where vibration analysis does a better job. I would suggest that a good lubrication program, in combination with regular vibration analysis is the best approach, at least for now until acoustic emissions becomes a proven technology for machinery analysis.

Vibration ,ultrasonic and acoustic emmision are all effective way for NDT.

you can refer to www.nde.net

there are lots of articles related to the issues.

PAC is a famous acoustic emmision company and has a branch in ou r china. you can get in touch iwht them as well.

I can also offer you another 40--100 channels ae teater. if you hope cheaper one.