- An air oil separator separates the oil vapor present in compressed air and returns it to the compressor’s oil sump where it is ready to be used as coolant again 

- The purpose of the separator is to prevent oil carry over and oil (coolant) consumption by removing the oil mist (oil vapor) from the compressed air, allowing it to recycle back to the air compressor to maintain lubrication 

- This ensures the compressed air remains free of oil droplets at air intake, which can cause contamination and damage to equipment using the compressed air