Product category:
Asset Management and maintenance planning
News Release from: AV Technology | Subject: SKF CMVA60 data collector
Edited by the Processingtalk Editorial
Team on 24 June 2004
When machines talk, it pays to listen to
vibration
AV Technology Ltd has been awarded an important predictive maintenance contract by Anglesey Aluminium Metal/Aliwminiwm Mon and the structured programme is already paying dividends
The Condition Monitoring division of Stockport based AV Technology Ltd (AVT) has been awarded an important predictive maintenance contract by Anglesey Aluminium Metal Ltd/Aliwminiwm Mon (AAM) and the structured programme is already paying dividends AAM produce high quality aluminium in the form of rolling ingots, extrusion billets and remelt ingots for its two equity partners, Rio Tinto and Kaiser Aluminium and Chemical Corporation, who are responsible for marketing the finished product through their respective trading organisations, Rio Tinto Aluminium and Kaiser Aluminium International Incorporated
This article was originally published on Processingtalk on 29 Jul 2003 at 8.00am (UK)
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AVT are primarily responsible for all the vibration monitoring on equipment both within the plant and at the AAM jetty.
AAM identified the critical machines for monitoring throughout the site and then AVT selected the appropriate monitoring interval for each monitored machine.
The monitoring intervals vary between one and six months, based on the duty and expected failure modes.
The AVT engineer spends approximately one and a half weeks each month collecting data on site using a portable SKF CMVA60 data collector.
The results are uploaded to a PC for trending and analysis using Rockwell's Entek 'Odyssey' software.
The company has significant experience in collecting and analysing condition monitoring data.
However, as Andy Mellor, Consulting Engineer for AVT explains: "Successful predictive maintenance requires more than just being able to collect and analyse large amounts of data and a number of key factors need to be considered.
We not only have a deep understanding of condition monitoring techniques, but also extensive experience of the machinery and equipment itself, in terms of how and where it operates and what can go wrong.
By identifying trends and patterns, AVT can predict possible failure scenarios.
Effective communication and good relationships with a wide range of plant personnel is also vital.
By working closely with management, engineers, craftspeople and contractors, we gain an understanding of their process and the opportunities for maintenance improvements at different areas within a plant.
All this allows us to make the right recommendations, at the right time, to the right person, so that appropriate action is taken.
Putting together a good report is no good if it is not acted on in a timely fashion".
As Mellor concludes: "Troubleshooting problematic machinery and persistent failures is another important facet of our work.
Again, close co-operation with the maintainers and OEMs is required.
Putting operational experience, maintenance history and design information together with our measurement and analysis capabilities gives us the capability to not only identify problems, but also to offer solutions".
The alumina ships, carrying around 25,000 tonnes, dock every four to six weeks from as far away as Jamaica and are off loaded at the AAM jetty using four suction exhauster unloading booms powered by Rootes Blowers.
Off loading typically takes four to six days and the equipment operates around the clock to minimise demurrage charges.
As a result any problems arising during this procedure are very inconvenient and expensive.
Prior to the predictive maintenance contract being put in place, AAM typically did not find out about a problem until it was too late.
A prime example of this was in 2002 when the bearings on the motor on one of the exhausters failed catastrophically, presenting AAM with a total repair bill of almost GBP80,000.
The current AVT contract started in August 2003 and within two months the site engineer had identified abnormal vibration patterns coming from the motor on Number 1 exhauster.
A detailed analysis was undertaken and the results clearly showed impacts on each revolution, together with other impacts between revolutions.
On close inspection, extensive fatigue damage was found on the top drive shaft end bearing and on the adjacent ball bearings.
There was also evidence that the inner ball races were moving on the shaft or relative to the spacers.
Acting on the AVT findings the AAM Reduction Services Maintenance team were able to remove and overhaul the exhauster in a planned and controlled manner in between ship dockings.
Not only did this not impact on production but the cost for repairs was only GBP8,000, ten times less than the cost incurred in 2002.
Adrian Jones, the AAM Maintenance Systems Specialist, is very upbeat about the program and believes its implementation has made his job easier.
As he points out: "Although this is not the only success story, it is the most significant.
We now know about problems before they happen, allowing us to take appropriate action.
AVT experience is also helping with the analysis of data from other condition monitoring work carried out around the site.
We have come to realise that machines talk and we should pay attention and listen to what they are telling us. Request a free brochure from AV Technology ...
'If it ain't broke don't fix it' is certainly NOT a policy we advocate.".
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