An aluminium production had recently undertaken an expansion and upgraded their processing systems with new cranes and


Case Study – Lubrication Oil in an Aluminium Smelter

A call to a leading Australian Aluminium Smelter revealed some exciting results.

The Objective

An aluminium production had recently undertaken an expansion and upgraded their processing systems with new cranes and gearboxes. The operators saw this as a great opportunity to improve overall plant performance so the maintenance team were tasked with:

  • Maximising their return on investment
  • Increasing the life cycle of the assets
  • Reducing unscheduled downtime.

The Problem

The smelter had been operating for many years with the usual plant maintenance systems and schedules – dumping and replacing hydraulic and gearbox lubes; all at some expense.
Asset life cycle was at a standard 10 years per gearbox but unscheduled maintenance and shut downs were a considerable cost they wanted to improve on.
Smelter environments are generally very dirty places with plenty of airborne particulate matter. This environment creates many opportunities for ingress and contamination of a hydraulic tank or gearbox lubrication system which in turn causes premature wear to rotating and sensitive components.  Further, the humid atmosphere made moisture a problem and significant temperature changes affected the service cycle of the oil.

The Challenge

The site wanted to lower maintenance costs, reduce downtime and increase asset life cycle. A review of the lubrication setup revealed that the oil was within tolerance but not at the clean end of the acceptable range. Regular replacement of contaminated lubricant was a solution but not a panacea due to the initial expense and the following rising contaminant levels afterwards anyway. The plant ideally wanted to use better quality lubricants and replace them less frequently. This would maximise their return on investment for both the lubricant and capital assets.

The Solution

The management assembled a team of Condition Monitoring personnel who devised a study and audit to improve asset reliability.
With lube oil sample analysis they were able to determine which contaminants were affecting their lubricants, where they came from, how they were getting in, the impact on components and wear rates.
The initial step was to fit breather filters to all lube oil compartments so they were able to remove all airborne contaminant ingress thereby keeping the oil cleaner. An important aspect was having a maintenance program in place as well so that the breathers were inspected, maintained and repaired as necessary.
The next phase was to improve the fixed conditioning filtration that operates on a kidney loop setup. Vacuum dehydrators equipped with 1000 filtration using 5 or 10 ¼m filters were implemented to significantly improve lube tank cleanliness and dehydrate the oil. These additions lowered their operating ISO 4406 code from new oil 21/18/17 (NAS Class 10) to 16/14/12 (NAS Class 5) for the compressors, and down to 15/13/11 (NAS Class 4) for their hydraulic assets! These steps increased the asset life cycle by a factor of 2½ and they now get 7 years of service from a hydraulic oil change.
By extending the lubricant life cycle they found they could afford to upgrade the lubricants to fully synthetic, thus extending asset and lubricant life cycle even further. This is a significant step in improving lubrication but it cannot happen if oil cleanliness and moisture is not well managed.

Purification Tasks


The condition monitoring team rotate their lubrication purification equipment throughout the plant, cleaning gearboxes, compressors and hydraulic assets. A well planned oil analysis program confirms their ISO 4406 operating targets, and trending enables early warning of any changes to wear rates or contamination.

Vacuum Dehydration Oil Purification System (VDOPS) with l²1000 2l¼m filtration


This smelter plant was able to increase their asset life cycle by 2½ times, improve lubrication efficiency thus maximising their overall return on investment by applying best practice methods. Coupled with a tight maintenance schedule the results were stunning.
If you are ready to increase the equipment life cycle of your plant then make contact with us:



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