Steam drum

The drum stores the steam generated in the water tubes and acts as a phase-separator for the steam/water mixture.

The difference in densities between hot and cold water helps in the accumulation of the "hotter"-water/and saturated-steam into the steam-drum.

The separated steam is drawn out from the top section of the drum and distributed for process.

Saturated steam is drawn off the top of the drum and re-enters the furnace in through a superheater.

Its accessories include a safety valve, water-level indicator and level controller.

Schematic diagram of a marine-type water tube boiler-see the steam drum at the top and feed drum
Boiler steam drum