Function of filter:

To remove foreign particles from the oil and remove sub micron particles dissolved in the oil.

Classification of filters:

1- Full flow filter

2- Proportional flow filter

Full flow filter:

• Incurs a large pressure drop.
• A relief valve is needed which cracks when the filter becomes blocked.

Proportional flow filter:

• Localised low pressure area is formed at the venturi.
• The fluid is drawn from the filter due to the pressure difference.
• low pressure drop