Predictive maintenance and fluid management in hydraulic systems: Boosting efficiency

Hydraulic systems have been used in a wide range of industries, from aerospace to manufacturing. They are pushed to the limit, despite their importance. In order to keep these systems operating smoothly and avoid costly downtimes, a two-pronged strategy focusing on Predictive Maintenance and Fluid management is crucial.

Power of Predictive Maintenance

Predictive maintenance is a game-changer compared to reactive or time-based maintenance. PdM predicts when maintenance is needed using data-driven insights, rather than waiting for components to fail or replacing parts according to a set schedule.

Key PdM Techniques for Hydraulics:

1. Vibration analysis: Monitoring rotating components such as motors, pumps, and bearings can detect imbalances or misalignments long before they lead to catastrophic failure. A rise in vibration intensity can often indicate a problem.

2. Temperature monitoring: Heat is the enemy of seals and hydraulic components. Thermal cameras and embedded sensors can identify Hot Spots within the fluid or reservoirs or on cylinders. This is often indicative of internal leaks or pump inefficiencies or high friction.

3. Pressure Sensing and Flow Rates: Analyzing flow rates and pressure fluctuations can help identify issues such as a clogged filter, pump degradation or internal valve leakage that reduce system efficiency.

4. Acoustic Monitoring: Listening to unusual sounds, such as cavitation within the pump, can provide early warnings that other sensors may miss.

PdM allows operators to move from expensive, unplanned repairs to focused, scheduled maintenance. This results in lower costs and longer component life.

Fluid management: the lifeblood of the system

Fluid is a vital component in a hydraulic system. It's not just a means of power transfer. 70 to 80% of hydraulic system failures are attributed to poor fluid conditions. Any successful PdM strategy is built on effective Fluid Management.

Hydraulic Fluid Management Principles:

1. Contamination Control (Filtration):

   • Solid Particles Contamination: Most common threat. Particles that are smaller than what can be seen by the human eye cause abrasive wear on pumps, valves and cylinders. Regular filter replacements and high-efficiency filtration are essential.

   • Contamination by Water: The water reduces the oil's lubricating qualities, promotes rust and accelerates oil degradation. The formation of varnish and sludge is caused by thermal and oxidative stresses combined with water.

2. Oil Condition Analysis (OCM)/Oil Monitoring:

   • Fluid PdM is based on this principle. Sending oil samples for analysis to a lab regularly provides a clear check on the health of the oil as well as the system components.

   • Key tests include:

     • Particle count: Measures the number and size of contaminants to indicate filter effectiveness and system wear.

     • Viscosity determines the correct oil thickness to ensure optimal lubrication.

     • Elemental analysis (Spectroscopy). Identifies worn-out metal particles (e.g. iron, copper, and chromium).

     • Acid number (AN): Tracks acidic byproducts and indicates the need for change.

3. Selection and handling of

   • It is important to use the correct viscosity and additive package as specified by the manufacturer.

   • Before adding fluid to the system, it should be cleaned and filtered (known as "kidney loop" filtration).

PdM and fluid management working together: The synergy

Combining these two strategies will maximize the benefits.

• Fluid Analysis (OCM). will tell you the health and the condition of the system. What the wearer is wearing, and the cleanliness of the fluid.

• Sensor-based PdM (Vibrations, Temperature, and Pressure) will tell you the immediate mechanical state, and alert you to sudden changes.

Integrating data from both sources allows maintenance teams to gain a complete view, which allows them to schedule maintenance precisely, avoid unnecessary oil changes, and reduce the risk of catastrophic failure. This proactive approach can save money and time while ensuring that the power of the system is delivered at maximum efficiency.