The Three Dimensions of Fluid Condition Management

The Three Dimensions of Fluid Condition Management

By: Drew D. Troyer

Fluid condition management is an often misunderstood activity. Many organizations utilize some form of fluid analysis, but many times they lose sight of the real objective of the program or inappropriately infer conclusions based upon oil analysis tests. An effective fluid management program is measured not by how many or what tests are performed, but rather by the impact of the program on the organization's productivity and profitability.

Fluid condition management, when properly implemented, delivers the following productivity and profitability improvements:

Minimized downtime.
Extended machine life.
Reduced labor costs.
Reduced fluid consumption and disposition costs.

The improvements are available because an aggressive fluid condition management program provides the user with machine and fluid information. Depending upon how this information is gathered and used determines the degree to which the user can effectively 1) control the wearing and degradation processes, and 2) control damage by predicting failure.

Most fluid condition management activities fall into one of the following three dimensions:

Fluid health analysis.
System condition monitoring.
Wear or damage analysis.

Dimension one, fluid health analysis, involves an inspection of the fluids physical, chemical, and additive properties to assure that the fluid is capable of operating in its designed function. A system designer selects a fluid because of it has features that compliment the system. Any deviation from specification can lead to system degradation. In general, these inherent fluid qualities are homogenous. A representative sample may be taken from nearly any point in the system. And, these parameters are not particularly volatile unless system trouble results in fluid degradation. While fluid health is an important parameter, one should avoid assuming that healthy fluid is indicative of a healthy machine.

Dimension two, system condition monitoring, is focused on the machine operating health. Even if the fluid is stable, the system can be in trouble. And such system problems tend to escalate exponentially when left unattended. At a basic level, machine conditions which are most effectively monitored through the fluid include particle contamination, moisture contamination, glycol and fluid dilution, and system temperature. Any of these conditions lead to system and fluid degradation and eventual system failure. Unlike fluid conditions, these machine conditions can change rapidly and should be monitored routinely. Monitoring intervals should be established by assessing the system's inherent sensitivity to the respective machine condition, and the criticality of the system to production. For example, an unspared hydraulic system with servo valves that carries a severe downtime penalty would warrant very frequent attention.

Unlike fluid health monitoring, because the condition is foreign to the fluid the point at which the sample is taken is critical to the quality of the information. Taking a sample from the reservoir of a hydraulic or lubricating system to perform a particle count can really lead to problems, especially if it is multi-circuit system. For example, assume that a six circuit hydraulic system has a wiper seal failure on circuit number three. The particles ingested by the failure are first combined with the fluid of the other five circuits, stripped by the return line filter, then diluted by the quantity of the fluid in the reservoir. The meat of the information is lost. Had the sample been taken from the return line of circuit number three, the cylinder failure, and ensuing downtime could have been avoided.

The third dimension of fluid condition management, wear or damage analysis, is most effective when it is avoided altogether. Aggressive control of fluid and system health can minimize the need for wear and damage analysis. But when a problem exists, the user requires information to first schedule predictive maintenance, and then repairs. In too many instances, users rely on the spectrographic analysis from their dimension one analysis to make their conclusions. This is a risky procedure because spectrographic analysis is limited to particles smaller than six microns in size. And, it looks only at elements. Without an understanding of the morphology, or shape of wear particles, it is difficult to make any real conclusions.

While these three dimensions of fluid condition management are very interdependent, one should clearly understand how each dimension impacts productivity and profitability so that information is gathered an assimilated to support effective maintenance decision making.

This story reprinted courtesy of Diagnetics.

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