a device for the deaeration of water—that is, the removal of gases dissolved in it. Deaerators are usually installed in steam power plants and are used to treat feed water delivered to steam generators and supplementary water delivered to the heating network. In the absence of deaeration the corrosive active gases usually dissolved in water (oxygen and free carbon dioxide), which are liberated in a steam generator or heating network, would cause corrosion of metals. Deaerators can be classified according to their principle of operation as thermal (the most widely used type), desorption, or chemical types.