The importance of condition monitoring on critical plant assets

The importance of condition monitoring on critical plant assets

by AVT Admin

One of the world’s largest snacks companies which manufacture products for their many big name brands appointed AVT Reliability® to provide condition monitoring services at a site in Ireland. With cost efficiency and continuous improvement being a key.

The plant employs approximately 80 people and produces chocolate crumb, which is supplied to other plants in Ireland, UK, Canada and the USA. The contract with AVT Reliability® supports 120 pieces of equipment by visual inspection, ultrasound, vibration and oil analysis to enable and inform the site’s new lubrication program.

With the decision made by the customer to adopt a condition based maintenance approach to asset care, the ultimate aim was to maintain compliance levels, improve efficiency and reduce costs.

AVT Reliability® set to work immediately by implementing a condition monitoring program and utilising Machine Sentry® to focus activities on the key reliability issues that the site was experiencing. The plant’s ‘Bad Actors’ were identified and Machine Sentry® facilitated with its stringent reporting capabilities and were highlighted by ADA™ the Automated Diagnostic Assistant and in turn the development of cost benefit data.

One area for concern involved the eight main cooker gearboxes and crystallisers. Previously, to maintain reliability, this equipment had full overhauls scheduled throughout the year which included routine replacement of the cooker bearings and oil in addition to full gearbox refurbishments. Despite performing this in depth routine maintenance, the plant was still experiencing ongoing issues with gearbox reliability and critical bearing failures which were costing over €500,000 in emergency repair costs.

Prior to entering the contract, AVT Reliability® carried out a lubrication benchmark assessment from which it was clear that the lubrication processes on site were not suitable. Oil analysis revealed contamination consisting of wear metal and water.

Automatic lubrication systems had been installed previously with good intention but with no policy change implemented to manage it, led to a lack of confidence in its reliability. With lubricants based on supplier data, the lubrication specified was unfortunately completely unsuitable for the machinery involved leading to serious reliability issues.

Following the implementation of the program, initial inspections of the cooker gearboxes discovered:

  • Water contamination in the gearbox
  • Light wear on lower bearings
  • Significant wear on helical worm gear ring
  • Thrust bearing showed signs of catastrophic failure (also seen in the vibration data)
  • Shaft damage due to fretting from lip seal
  • Scoring of the bearing housing
  • Oil seal damage
  • Grease was being used as gearbox lubricant to alleviate on going issued with leaking lip seals.

Working closely with the customers onsite team, root cause analysis and assessment of the gearbox, defined a number of follow up actions which were subsequently taken:

  • The shaft lip seals were replaced with LabTecta® bearing protectors. The LabTecta® is manufactured by AESSEAL® (another part of the AES Engineering group) and is designed to eliminate water ingress and prevent oil leakage.
  • The lubricants were changed to Petro Canada food grade
  • Gauges were trialled to enable periodic visual inspection of the gearbox oil level. Work on this is still ongoing.
  • Based on the output of the condition monitoring program improvements were made to the gearbox installation procedure in order to improve reliability. This included alignment practices and bracing of gearboxes to reduce impact of structural looseness.

The first unit was installed with the LabTecta® bearing protector in 2015 and has remained in service without further issues. An additional three cooker gear boxes have also been upgraded with the remaining units will be upgraded at the next convenient opportunity.

Following the successful implementation of the condition based monitoring program, AVT Reliability® continue to meet and support the onsite team regularly in the drive to maintain the reliability of the gearboxes.

The plant is also using Machine Sentry® to log actions. This proactive approach by the customer and their willingness to fundamentally change how maintenance is carried out on site has resulted in a significant increase in equipment reliability and cost avoidance in excess of €840,000 have already been realised.

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