Aux 1 Unit 8 Q6

On an ocean-going vessel, hydraulic systems are particularly vulnerable to contamination due to the harsh marine environment and the complexity of onboard operations. Here are some of the possible contaminants that can find their way into these systems:

1. Particulate Contamination:

• Dust and Dirt: Airborne dust and dirt can enter the system through the reservoir breather, leaks in seals, or during maintenance activities.
• Metal Wear Particles: Normal wear and tear of internal components like pumps, valves, and actuators generate metal particles that circulate in the fluid.
• Sand and Silt: Seawater used for cooling or other purposes can introduce sand, silt, and other abrasive particles into the system, particularly if the intake is not adequately filtered.
• Other Debris: Various other debris like rust, paint chips, fibers, and even insects can find their way into the system.

2. Water Contamination:

• Condensation: Moisture from the air can condense inside the reservoir or other parts of the system due to temperature fluctuations, especially in humid marine environments.
• Seawater Ingress: Leaks in seals, pipes, or fittings can allow seawater to enter the system, especially in areas exposed to the elements.
• Coolant Leaks: In systems with heat exchangers, leaks can allow coolant (often water-based) to mix with the hydraulic fluid.

3. Air Contamination:

• Leaks in Suction Line: Air can be drawn into the system through leaks in the suction line, connections, or fittings, particularly if the fluid level in the reservoir is low.
• Improper Bleeding: Air can become trapped in the system during maintenance or repairs if proper bleeding procedures are not followed.
• Cavitation at the Pump: If the suction pressure is too low, cavitation (formation and collapse of vapor bubbles) can occur, introducing air into the system.

4. Oil Contamination:

• Lubricating Oil: In some cases, lubricating oil from the compressor or other machinery can contaminate the hydraulic fluid if proper sealing and separation are not maintained.
• Other Sources: Contamination can also occur from spills or leaks of other oils or greases used onboard.

5. Chemical Contamination:

• Incompatible Fluids: Accidental mixing of incompatible fluids, such as cleaning solvents or other chemicals, can contaminate the hydraulic fluid and cause degradation or chemical reactions.
• Fluid Degradation Byproducts: The hydraulic fluid itself can degrade over time, producing acidic byproducts or varnish that can further contaminate the system.

6. Microbiological Contamination:

• Bacteria and Fungi: Water contamination can create an environment for bacteria and fungi to grow within the hydraulic system. This can lead to further contamination, corrosion, and even clogging of filters.

Consequences of Contamination:

• Reduced Performance: Contamination can cause sluggish operation, loss of power, and decreased efficiency of the hydraulic system.
• Component Damage: Abrasive wear, corrosion, and chemical reactions can damage pumps, valves, actuators, and other components, leading to leaks, malfunctions, and premature failure.
• Safety Hazards: Malfunctioning controls or equipment failure due to contamination can create safety risks on board.
• Increased Maintenance Costs: Contamination necessitates more frequent maintenance, repairs, and fluid changes, increasing operational costs.

Prevention is key: Implementing proper filtration, regular maintenance, and careful handling of fluids are essential to prevent contamination and ensure the reliable and long-lasting performance of hydraulic systems on marine vessels.

Eliminating contaminants from hydraulic systems on board an ocean-going vessel requires a multi-pronged approach that involves preventive measures, regular maintenance, and specific techniques to remove contamination when it occurs. Here’s a breakdown of effective strategies:

Prevention:

1. Filtration:

• Multi-Stage Filtration: Implement a comprehensive filtration system with various filter types and micron ratings strategically placed throughout the hydraulic system.
  • Suction Strainers: Coarse filters at the reservoir inlet prevent large debris from entering the pump.
  • Pressure Filters: Fine filters in the pressure line capture smaller particles before they reach sensitive components.
  • Return Line Filters: Filters in the return line capture wear debris and contaminants before the fluid returns to the reservoir.   1. The vital role of return line filters in hydraulic systems www.ufihyd.com
    1. Maintaining hydraulic system health: the crucial role of contamination control www.ufihyd.com

2. Seals and Gaskets:

• Regular Inspection and Replacement: Inspect seals and gaskets regularly for signs of wear, damage, or leaks. Replace them promptly to prevent ingress of external contaminants like water, dust, or seawater.   1. 5 Essential Steps to Combat Contamination in Hydraulic Systems – Lubeco Green Fluids lubecogreenfluids.com
• High-Quality Seals: Use seals and gaskets made from materials compatible with the hydraulic fluid and the operating environment to ensure their longevity and effectiveness in preventing leaks.

3. Fluid Maintenance:

• Proper Storage and Handling: Store new hydraulic fluid in clean, sealed containers and use proper transfer procedures to minimize the risk of contamination during filling.   1. Reducing the Effects of Contamination on Hydraulic Fluids and Systems www.machinerylubrication.com
• Regular Fluid Analysis: Conduct periodic fluid analysis to monitor the fluid’s condition and detect any contamination early on. This allows for timely corrective action before significant damage occurs.
• Fluid Change Intervals: Follow the manufacturer’s recommendations for fluid change intervals to ensure the fluid remains clean and in good condition.

4. Cleanliness and Best Practices:

• Clean Work Environment: Maintain a clean work environment during maintenance and repairs to prevent the introduction of dirt, dust, or other contaminants into the system.
• Proper Cleaning of Components: Thoroughly clean any components before reassembly to remove any residual contaminants.
• Use of Clean Tools and Equipment: Use clean tools and equipment specifically designated for hydraulic system maintenance to avoid cross-contamination.

Contamination Removal Techniques:

1. Draining and Flushing:

• For Minor Contamination: If contamination is detected early and is localized, drain the affected section of the system and flush it with clean hydraulic fluid to remove contaminants.

2. Filtration and Recirculation:

• Offline Filtration: Use a portable filtration unit to circulate and filter the hydraulic fluid while the system is offline, removing particulate matter and other contaminants.
• Kidney Loop Filtration: Install a dedicated filtration loop (kidney loop) in the system to continuously filter the fluid during operation, helping to maintain cleanliness.

3. Vacuum Dehydration:

• For Water Contamination: This specialized process removes water from the hydraulic fluid by heating it under a vacuum, causing the water to evaporate and be extracted from the system.

4. Centrifugation:

• For Particle and Water Removal: Centrifuges can be used to separate solid particles and water from the hydraulic fluid based on their density differences.   1. Hydraulic Oil Centrifuge: Operation, Uses, Benefits & Specifications dolphincentrifuge.com

5. Chemical Flushing:

• For Severe Contamination: In cases of severe contamination or the presence of stubborn deposits, chemical flushing might be necessary to dissolve and remove contaminants from the system.

Important Considerations:

• Safety: Always follow safety procedures, including lockout/tagout procedures, when working on hydraulic systems.   1. What Are Hydraulic System Safety Precautions and Hazards? | Cylinders, Inc. cylindersinc.com
• Consult Experts: For severe contamination or complex systems, consult a qualified hydraulic technician or engineer for proper diagnosis and remediation.

By implementing these preventive measures and employing appropriate contamination removal techniques, you can effectively eliminate contaminants from hydraulic systems on board a vessel, ensuring their optimal performance, reliability, and longevity.