Oil is also a system component
Fluid condition directly affects pumps, valves, actuators and control devices. Filtration should be treated as part of a reliability strategy rather than simply as an accessory.
Main forms of contamination
| Type | Possible effects |
|---|---|
| Solid particles | Abrasive wear, blockage of small passages, erosion and loss of precision. |
| Water | Corrosion, additive deterioration, lubrication changes and component damage. |
| Air | Irregular response, noise, cavitation, oxidation and efficiency loss. |
| Fluid degradation | Varnish, deposits, viscosity increase and obstruction of sensitive elements. |
Indicators of changes in fluid condition
- Changes in oil colour, smell or appearance.
- Filters reaching saturation more frequently.
- Operating temperatures above normal.
- Erratic motion, loss of precision or slower response.
- Abnormal pump noise or visible foam.
- Repeated failures in valves or sensitive components.
Sampling as part of diagnosis
Sampling can reveal cleanliness, water, wear or degradation. Interpretation must consider how and where the sample was taken, the system type, fluid history and component requirements.
A sample taken from an unrepresentative point or with a contaminated container can lead to incorrect conclusions. Use a repeatable procedure and record date, operating hours and equipment conditions.
Contamination control
Define the cleanliness objective
Components with tight clearances generally need tighter control. The target should reflect installed technology and process criticality.
Select the filtration point
Pressure, return, suction or offline filtration may be considered. The right architecture depends on the circuit and the risk being controlled.
Monitor and maintain
Filter-clogging indicators, particle measurement, water control and maintenance records support a shift from reactive failure response towards preventive management.
Variables for filtration assessment
Fluid type and volume, flow rate, pressure, temperature, current condition, installed filter codes and failure history provide the context required to assess system performance.