A deaerator is a device that is widely used for the removal of oxygen and other dissolved gases from the feed water to steam-generating boiler.

In particular, dissolved oxygen in boiler feed waters will cause serious corrosion damage in steam systems by attaching to the walls of metal piping and other metallic equipment and forming oxides.

Most deaerators are designed remove oxygen down to levels 7 ppb by weight or less as well as essentially eliminating carbon dioxide.