With reference to hydraulic systems:
(a) state THREE possible contaminations;(3)
(b) state possible causes of the contaminations stated in part (a).(3)
(c) explain how the contaminants stated in part (a) are prevented from affecting the system.(4)
Question 4.
Well answered by most.
Hydraulic systems contamination
Hydraulic systems are prone to various types of contamination that can severely impact their performance, efficiency, and longevity. Here are the most common contaminants found in hydraulic systems, particularly on a vessel:
- Particulate Contamination:
- Solid Particles: These include dust, dirt, sand, metal shavings, wear debris from internal components, and other solid particles that can enter the system through various means.
- Effects:
- Abrasive Wear: Particles can act like sandpaper, causing abrasive wear on pumps, valves, actuators, and other components, leading to increased clearances, leakage, and reduced efficiency.
- Clogging and Blockages: They can clog filters, orifices, and other small passages, disrupting flow and causing malfunctions.
- Water Contamination:
- Sources: Water can enter the system through condensation in the reservoir, leaks in seals or fittings, or contaminated hydraulic fluid.
- Effects:
- Corrosion: Promotes rust and corrosion on metal surfaces, weakening components and causing leaks.
- Oxidation and Fluid Degradation: Accelerates the breakdown of hydraulic fluid, reducing its lubricating and heat transfer properties.
- Microbial Growth: Provides an ideal environment for bacteria and fungi to thrive, leading to further contamination and corrosion.
- Air Contamination:
- Sources: Air can enter the system through leaks in the suction line, low fluid levels in the reservoir, improper bleeding procedures, or cavitation at the pump.
- Effects:
- Spongy or Erratic Operation: The compressibility of air causes inconsistent actuator movement and sluggish response.
- Reduced Efficiency: Air absorbs energy from the system, leading to power loss and reduced efficiency.
- Noise and Vibration: Air bubbles create noise and vibration as they travel through the system and collapse.
- Cavitation: Air bubbles can lead to cavitation, causing damage to the pump and other components.
- Chemical Contamination:
- Sources: Can come from incompatible fluids, degradation byproducts of the hydraulic fluid, or external contaminants.
- Effects:
- Seal and Component Degradation: Can cause swelling, shrinking, or hardening of seals and other components, leading to leaks and malfunctions.
- Fluid Breakdown: Can accelerate the degradation of hydraulic fluid, reducing its performance and lifespan.
- Other Contaminants:
- Microorganisms: Bacteria and fungi can thrive in water-contaminated systems, leading to further contamination and corrosion.
- Process Contaminants: Depending on the application, the system might be exposed to other contaminants like dust, chemicals, or process by-products.
Preventing Contamination:
- Filtration: Use appropriate filters at various points in the system to remove particulate matter and other contaminants.
- Seals and Gaskets: Maintain good seals and gaskets to prevent leaks and ingress of external contaminants.
- Fluid Maintenance: Regularly check and change the hydraulic fluid according to manufacturer recommendations.
- Cleanliness: Maintain a clean working environment during maintenance and repairs to prevent the introduction of contaminants.
By understanding the types of contamination and their sources, and implementing preventive measures like filtration, maintenance, and cleanliness, you can effectively safeguard hydraulic systems from contamination, ensuring their optimal performance, reliability, and longevity.