Contamination exists all around us, but we must prevent its intrusion into our lubrication systems to help keep our machines alive for a longer period. Some simple steps can be performed to help reduce levels of contamination. Also, lab tests can identify the presence of contaminants.
Storage & Handling
Unfortunately, this is the area in which many of the contaminants enter the lubricant. There is no discrimination in this area because all solids, liquids and gases can easily contaminate the lubricant.
Some best practices to follow are to first ensure that all lubricants are properly labeled and that everyone on the team knows the different uses for each lubricant. While this may seem simple, some people think that “oil is oil,” and any oil can work. Educating them on the differences and their effects of being mixed is critical to ensuring that they don’t get mixed up (or used as a contaminant to another lubricant).
Typically, with construction equipment, a lot of smaller sumps do not require a full pail of oil or may require an odd volume of oil. This often means that new unused oil either remains in the original packaging or is transferred to a holding container. If the new oil remains in the original packaging the user should ensure that the packaging remains sealed after use; is airtight (not to allow any other particles in); and stored in a cool, dry place.
If it is decanted into another container, this container needs to be:
- Clean (not previously used for another oil, not “cleaned” using fuel or some other substance)
- Properly capped (to prevent any contaminants from entering)
- Kept in a cool, dry place
Filtration
While this may seem trivial, lots of users assume that their new lubricants meet the required cleanliness standards for their machines. This is not true. New lubricants can be dirty and should be filtered before use. The filtration specification will vary depending on the cleanliness required for your machine.
For instance, the cleanliness specification for a hydraulic machine will be different from that of the engine oil specifications because hydraulics have closer clearances. Although many machines contain system filters which will also catch some of the contaminants, it is always a best practice to filter all lubricants before placing them in your system.
Oil Analysis
Oil analysis is not a likely method to prevent contamination, but it can inform end users of the presence of contaminants. Because of this benefit, it should be used to monitor the level of contaminants in a lubricant and trend their increase or decrease over time. This can spot whether a leak in the system, if a correlation between wear and contaminants exists or an anomaly is present in the system.
The tests that should be used to identify the presence of contaminants include:
- Viscosity (to determine if there is change in this value)
- Fourier transform infrared spectroscopy
- Elemental (to identify wear metals, additives and contaminants)
- Karl Fischer or crackle for the presence of water or fuel
Elemental analysis can easily help identify the presence of wear metals or contaminants, but it can also identify the presence of additives that are not representative of the oil in use. This is a good way of identifying the presence of an incorrect lubricant or solution that may have been used during a top up for that component.
Example
A mixed fleet operator began noticing that the jobs allocated to the excavation crew were taking twice as long as usual, and the costs associated with those jobs for materials also increased. He decided to tag along with the site manager for one of these projects to understand the escalation of the hours and costs.
At the site, the project began smoothly and ran as it should for the first two weeks. Afterwards, he noticed that the equipment began experiencing some downtime on the site. Typically, this occurred on the day after the site maintenance crew carried out their lubricant top ups.
The lubricants were being stored in the elements close to a makeshift shed that held some other necessary tools. The maintenance crew did not have smaller containers to decant the oils for the hydraulic equipment, so they used their disposed soda bottles to “help.” Any lubricant that remained in the bottle was left open to the atmosphere, and then this was topped up by the new lubricant.
Unknowingly, these users were contaminating their oil before placing it in the machines. This led to the unplanned downtime and extra resources, such as more oil, filters and hours for the mechanic. Immediately, proper storage and decanting containers were purchased. The onsite staff was trained in using these containers, which were also color coded to avoid the mixing of different lubricants.
The allocated time for these jobs returned to normal. In addition, the costs associated with the materials decreased because they no longer had to purchase extra oil to make those oil changes when the equipment shutdown.
Contamination can have a significant impact on the downtime of your equipment but can be easily prevented by using proper storage and handling techniques and monitoring the presence/absence of particles through oil analysis.
References
SKF, (June 6, 2024). Solutions for Contamination. Retrieved from SKF: https://www.skf.com/group/industries/mining-mineral-processing-cement/insights/solutions-for-contamination.