Vacuum Deaerators-An Overview

Vacuum Deaeration is a method of removing dissolved gases from water.  Removing dissolved gases from water is necessary as they can cause corrosion.

The principle on which Vacuum Deaerators are based is called Henry's Law.  Henry's Law states that the gas solubility in a solution reduces as the partial pressure of the gas above the solution decreases.
The Deaerator consists of a tower with baffles.  The tower is made of galvanized or reinforced
steel.

Water is drawn to the top of the tower and made to fall through the baffles.  The falling water is in the form of thin films.  This creates a large contact area between the water and the air. 

A vacuum pump creates a vacuum in the inside of the tower.  This lowers the air pressure on the inside.  The dissolved gases in the water are drawn to the vacuum and are removed.

In some vacuum deaerators the water is increased in lower the solubility.  The amount of vacuum to be created depends on the temperature of the water.  Vacuum deaerators are highly efficient and can deliver water with dissolved oxygen less than 5 ppb (parts of billion).