Fluid/Oil Analysis

Abstract:
A fluid or oil analysis program is one of the most widely used predictive maintenance programs. This type of program can be applied to any rides that are dependent upon fluid lubricants for continued operation. Fluid analysis provides valuable information as to the internal condition of oil-wetted components and information about lubricant serviceability. A combination of physical and spectrochemical tests is used to monitor lubricant and component condition. Almost any ride or machine which has a lubricating system can be placed in an oil analysis program. The components whose performance directly affects the continued operation of a particular ride are the most likely candidates for routine oil analysis.

Details:
A spectrochemical analysis identifies and measures selected metallic elements present in the lubricant as microscopic particles. Test results are reported in parts per million (ppm) by weight. The relative concentrations of these elements are used to monitor wear rates, detect contaminants and determine additive levels.

Once an analysis is performed, the lab will interpret the data. Most laboratories will classify the lubricant condition and relative severity of contamination and wear into several categories such as normal, monitor, abnormal and critical. These classifications are relative and are usually assigned using trend analysis and condemning limits.

When trend analysis is used, as in the case of wear metals and certain contaminants, threshold values are developed to identify the boundary area between normal and abnormal results. For wear metals, these threshold values vary for different types of components, but are specific and stable for each individual model of a given application. For example; a Scrambler™ gearbox at different facilities will have the same unique threshold value. These values do not provide sharp lines of "normal/abnormal" interpretations; instead, they indicate ranges of increased likelihood that a problem has developed to a particular component. Generally, the lubricant and component condition can be considered "normal" as long as the wear metal, contamination and lubricant deterioration levels remain within the established ranges. Regardless of the threshold values, however, any sharp increase in wear materials or major shift in physical properties can signal initial problems. Therefore the threshold values cannot be used as go/no-go criteria.

Uses:
The primary objectives of a Fluid Analysis Program are:

• Increase margins of operational safety.

• Increase availability by decreasing downtime. Reduce in-service failures.

• Control standby equipment and spare component requirements.

• Increase overall component life span.

• Eliminate unnecessary overhauls or inspections.

• Establish proper lubricant service intervals.

• Identify and measure lubricant contamination and component wear.

• Improve cost assessment and control for equipment, labor and materials.

Additional information:

General Procedures:
Although the fluid analysis is typically performed at a remote lab, facility personnel are responsible for obtaining the samples to be tested. Obtaining a representative sample is one of the most important parts of a scheduled oil analysis program. If a sample does not represent the true condition of the lubricant and component at the time of sampling, the reliability of the test results and their interpretation is affected.

Sampling Points:
Areas where lubricant flow is restricted or where contaminants and wear products tend to settle or collect should be avoided as sampling points. To insure that wear products and lubrication contaminants are thoroughly mixed with the lubricant, the sample should be taken immediately after shutdown. This will prevent the heavier wear particles from settling out.

The following are acceptable sampling points:

Once the proper sampling point and method is determined, oil samples should always be obtained from the same point, utilizing the same method every time.

Sampling Procedure:

Identification:
All fluid sampling locations should be identified for consistent samples and sample repeatability. All fluid reservoirs such as hydraulic systems and gearboxes should be identified with the fluid content and the date of the last fluid change. This identifier can be a tag placed on the unit near the fill port or sample location.

All fluid samples should be identified on the bottle with the date, ride name, type and grade of oil, all oil additives or additional fluids, sample location and the name of the person obtaining the sample.

Information which should be provided to the fluid analysis laboratory: