What Causes Air Contamination and Cavitation in a Hydraulic System?

Air contamination and cavitation in a hydraulic system are two common issues that can lead to reduced performance, damage to components, and even system failure.

Common Causes of Air Contamination:

Air contamination occurs when air enters the hydraulic system, disrupting fluid flow and causing issues like reduced efficiency, pump damage, and erratic system behaviour.

1. Low Fluid Levels:

Cause: When fluid levels are low, the hydraulic system can draw in air, especially at the inlet of the pump.
Solution: Maintain the correct fluid levels to prevent air from entering the system.

2. Leaky Seals or Fittings:

Cause: Loose or damaged seals, fittings, or connections can allow air to enter the system.
Solution: Regularly check and replace damaged seals or tighten any loose fittings.

3. Improperly Sealed Reservoir:

Cause: A faulty or improperly sealed reservoir can let air into the system, especially during fluid intake.
Solution: Ensure the reservoir is tightly sealed to prevent air ingress.

4. Suction Line Issues:

Cause: A damaged or poorly connected suction line can cause air to enter the system at the pump inlet.
Solution: Inspect and repair any issues in the suction line to ensure a secure connection.

5. Fluid Contamination:

Cause: Air bubbles can be introduced into the fluid if it's contaminated with water, causing foam formation.
Solution: Use high-quality fluid and maintain clean conditions to avoid contamination.

Common Causes of Cavitation:

Cavitation occurs when the pressure in the pump drops below the vapor pressure of the fluid, causing the formation of vapor bubbles, which collapse and create shockwaves. This leads to erosion, noise, and decreased pump efficiency.

1. Low Fluid Levels:

Cause: If the fluid level is too low, the pump may draw in air or fail to maintain sufficient pressure, causing cavitation.
Solution: Ensure fluid levels are topped up to the recommended levels

2. Blocked or Restrictive Suction Line:

Cause: Any blockages or restrictions in the suction line reduce the flow of oil to the pump, causing a drop in pressure and leading to cavitation.
Solution: Inspect and clean the suction line regularly to ensure smooth, unobstructed flow.

3. Excessive Pump Speed:

Cause: Operating the pump at too high a speed can cause the fluid to flow too quickly, reducing pressure and increasing the chances of cavitation.
Solution: Ensure the pump is running at the recommended speed for optimal performance.

4. Incorrect Pump Sizing:

Cause: An undersized pump may struggle to provide adequate flow and pressure, leading to cavitation, especially under high load conditions.
Solution: Ensure that the pump is properly sized for the application to avoid pressure drops.

5. High Fluid Temperature:

Cause: High fluid temperature lowers the fluid's viscosity, making it more prone to cavitation.
Solution: Maintain proper fluid temperature by ensuring the cooling system is functioning and not overheating.

6. Faulty Pressure Relief Valve:

Cause: A malfunctioning or improperly set pressure relief valve can cause excessive pressure drops, leading to cavitation.
Solution: Inspect and adjust the pressure relief valve regularly to maintain optimal pressure levels.

7. Excessive System Load:

Cause: Operating the hydraulic system beyond its rated capacity can result in excessive pressure drops and cavitation.
Solution: Avoid overloading the system and operate within its specified limits.

Preventing Air Contamination and Cavitation:

Regular Maintenance: Perform routine inspections to identify leaks, ensure proper fluid levels, and check for system blockages.
Seal and Filter Integrity: Ensure all seals are intact and filters are clean to prevent air contamination and cavitation.
Proper Sizing and Operation: Make sure the pump and system are correctly sized and operated within the manufacturer's specifications to avoid both issues.

By addressing these causes and performing regular maintenance, you can prevent air contamination and cavitation, ensuring your hydraulic system operates efficiently and reliably.