Onsite Oil Analysis Vital for Immediate, Accurate Results

Jennifer M. Cypress, Emerson Process Management; Thomas A. Gabany, NASA Langley Research Center

Simple, fast and reliable onsite oil analysis should be an integral part of any plant maintenance program. It's one technology that is inexpensive to implement, and the money saved by being able to identify machine failure, oil quality, handling and other problems before they become costly is impressive.

Today's sophisticated onsite oil analysis kits can detect changes in oil quality, contamination, wear and chemical differences. Valuable information like this helps plant personnel extend equipment service life and intervals between oil changes, reducing waste oil, maintenance and oil purchase costs. These benefits can produce substantial savings in a short time.

In 1994, NASA Langley Research Center was not new to the idea of oil analysis. In the past, maintenance workers had been in the practice of obtaining oil samples from about 552 lubricating systems and sending them to an off-site laboratory for testing. The problem with this procedure, they realized, was that the center's maintenance personnel did not have the necessary knowledge to interpret the lab reports effectively.

As a result, the reports were simply scanned for obvious problems, like the presence of water, and otherwise ignored. As a result, the program failed to significantly reduce maintenance and oil costs, reduce oil waste or generate a noticeable savings to the organization.

In 1995, NASA Langley decided to get serious about oil analysis. They purchased an OilView® analyzer from Computational Systems Incorporated along with the monitor's accompanying oil analysis software for the purpose of running wear debris tests. In 1996, they added a particle counter and a viscometer to their program. After receiving some training, the oil program finally took off. Now they perform onsite monitoring on 193 lubricated systems quarterly for wear, cleanliness and oil degradation. They are in the process of adding 144 hydraulic systems to the test schedule.

Since the purchase of the particle counter, Langley has been able to monitor system cleanliness. They have realized that oil can be filtered using portable filtration systems equipped with appropriate hose connectors to reduce waste, disposal costs, new oil purchase costs and maintenance costs.

Catching Particulate Contamination and Cross Contamination

While using the particle counter, it was discovered that the act of replacing oil introduced unacceptable levels of contamination, leaving the systems above their pre-set target cleanliness levels. It was also discovered that their oil handling and storage practices were a major source of contamination ingress. They found that oil was being transferred from the drums to the machines in dirty coffee cans or other unsuitable open containers. Likewise, transfer pumps were being stored improperly.

These poor handling practices not only caused the ingress of solid contamination, but they were also found to be a source of cross-contamination of different oil types in the systems. Cross contamination can cause a change in viscosity. If the oils are chemically incompatible, the oils can destroy themselves, damage system seals, and even damage system components.

In one instance, cross-contamination of a phosphate ester fluid with a mineral oil created a seal incompatibility problem. The oil transfer system was identified as the culprit for the cross-contamination. Since then, separate pumping systems have been assigned to the mineral oils and phosphate ester oils respectively to avoid the recurrence of such a problem.

Prior to implementing the onsite oil analysis program, the belief was that few failures had occurred because of oil related conditions. After reexamining some old files, it was discovered that the center's history of resistance to oil analysis was based upon misinformation.

On all of the machinery failures documented in the past, oil related failure had never been identified as the cause except in those instances where a physical loss of lubricant had occurred. However, in photographs of worn machine surfaces, one can clearly see definite signs of the onset of oil related failure. Because of a lack of training in oil analysis, Langley Staff were unable to identify failures relating to the oil.

Minor Error Causes Oil-Related System Failure

One of the test fixtures used for research was experiencing abnormal pump failure after only 10 hours, or less, of operation. Oil analysis showed that the hydraulic fluid was heavily contaminated with solid particles. Microscopic analysis indicated brass wear debris, paint, spiral wear debris, and heat-tempered particles.

It was discovered that the brass wear was being generated because of other contaminants left in the reservoir during the modification of an oil return line. The paint was present due to preparation of the surface for welding. The spiral particles were the result of drilling activities and the heat-tempered particles turned out to be weld spatter.

As a result of not cleaning the system after the modification to the return line, NASA ended up spending approximately $6,000 to rebuild the system. This figure does not include lost research and the cost of downtime. Oil analysis, when properly deployed, could have ensured that the system was "roll-off clean" prior to initializing operation, avoiding these costs altogether.

Avoiding Costly Wastefulness

NASA Langley's most recent attempt to save money through oil analysis is actually a work in progress at the time this paper was published. There is a high leak rate of Fyrquel 550 phosphate ester oil on one of the vacuum pumps due to damaged seals and design problems.

Until the redesign of the system can be accomplished, the leaking oil is being directed to 55-gallon drums and disposed as waste oil. The leak rate is severe enough to result in an accumulation of one 55-gallon drum every ten days. The cost of the oil is $1,500 per drum, and disposal adds another $75 per drum.

After disposing of 19 drums at a total cost of $29,925, the oil analysis team pursued options to cut this tremendous cost with oil analysis. Preliminary oil analysis suggested that this oil was most likely reusable after removing dirt and water contamination. A final decision is pending receipt of full test results, but the decision has been made to proceed with the reclamation, and the prospects are promising.

As you can imagine, the cost saving potential is tremendous with a good on-site oil analysis kit, especially when it is combined with some basic training in oil analysis. If you are considering upgrading your maintenance program to include predictive or condition-based maintenance strategies, oil analysis is an inexpensive path that can provide a big return on investment.

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