Steam Drum is used to permit the separation of saturated steam from the steam-water flow and send it to the super heater or directly to an end use. It serves to mix the feed water with the water discharged from the steam-water separators, water treatment chemicals, and purify the steam prior to discharge, remove part of the water to control boiler water chemistry and provide limited water storage to accommodate rapid boiler load changes. The continuous blow down piping is placed in the drum at a point below the water level where the concentration of solids tends to be highest. The steam outlet is normally a series of tubes at the top of the drum that carry steam to the super heater. In low-steam-flow situations, natural steam separation by gravity at the steam water surface in the drum can be sufficient depending upon the drum size, steam flow rate and operating pressure.