Chapter 5 - Feed systems

Abstract

This chapter presents feed systems. The feed system completes the cycle between boiler and turbine to enable the exhausted steam to return to the boiler as feed water. The feed system is made up of four basic items: the boiler, the turbine, the condenser, and the feed pump. Other items are incorporated into all practical feed systems, such as a drain tank to collect the condensate from the condenser and provide a suction head for the feed pump. A make-up feed tank will provide additional feed water to supplement losses or store surplus feed from the drain tank. In a system associated with an auxiliary boiler, as on a motor ship, the drain tank, or hot well will be open to the atmosphere. Such a feed system is therefore referred to as open feed. In high-pressure water tube boiler installations no part of the feed system is open to the atmosphere and it is known as closed feed. Packaged feed systems are also available from a number of manufacturers. With this arrangement, the various system items are mounted on a common base or bedplate. The complete feed system may be packaged or a number of the items.