Abstract
This paper examines the basic principles governing the operational behaviour of the two types of deaerator systems best suited to the requirements of modern industrial steam plants of medium to large size. The two basic types of deaerator systems comprise a ranged pair of turbines with similar associated deaerators. Modulated control of the condensate level in the storage tanks provides an essential role in the steady state operation of the system. In the interests of clarity and brevity only the simplest possible cases have been considered and the more complex situations frequently encountered in practice require some adjustments to the procedures described.