Boiler: A close vessel which generate stem by heating water.
Working Principle: Its heat exchange with shell and tube.
Type: Horizontal vertical inclined fire tube water tube.
Advantage of super heater:
A. Efficiency of turbine increase.
B. Turbine blade erosion eliminated.
C. Stem consumption of turbine reduce.
D. Loss due to condensation in cylinder and stem pipe is reducing.
Shell and tube boiler refer as fire tube or smoke tube boiler fire tube boiler initially have lower cost and more fuel efficient and easier to operate .their capacity are up to 25 tonne per hr and pressure 17.5 kg per cm
Cornish boiler these are easiest form of high pressure tube boiler .This consist of long horizontal cylinder with single large flue containing fire.
Lancashire boiler it have two large flue container of fire pressure range .7 mpa to 2 m pa and eff. 65-70%.
Main component double walled fire box, horizontalcylinder containing large no of small flue tube wet steam goes through super heater. Wet back boiler reverse chamber completely surrounded by water .three pass boiler stack temp is less than two pass boiler efficiency is than two pass.