Steam Boilers, Engines, Nozzles and Turbines
In forced recirculation type boiler,

Feed pump is employed to supplement natural circulation in water wall type furnace
Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
Water is converted into steam in one pass without any recirculation
Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam