Boilers can be delegated pursues:
1. As indicated by the stream of water and hot gases – fire cylinder (or smoke cylinder) and water tube boilers.
In flame tube boilers, hot gases go through cylinders which are encompassed with water. Models: Vertical, Cochran, Lancashire and Locomotive boilers. There might be single cylinder as in the event of Lancashire evaporator or there might be a bank of cylinders as in a train heater.
In water tube boilers, water circles through countless and hot gases go around them. Eg., bobcock and Wilcox kettle.
2. As indicated by the pivot of the shell – vertical and level boilers.
3. As indicated by area or position of the heater. Remotely and inside let go boilers.
In inside let go boilers, the heater shapes a basic piece of the boilers structure. The vertical cylindrical, train and the scotch marine boilers are outstanding precedents.
Remotely shot boilers have a different heater worked outside the kettle shell and for the most part underneath it. The flat return tube (HRT) evaporator is likely the most broadly known case of this sort.
4. As indicated by the application – stationery and portable boilers. A stationary boilers is one of which is introduced for all time on a land establishment.
A marine heater is a versatile evaporator implied for sea load and traveler ships with a characteristic quick steaming limit.
5. As per steam weight – low, medium and high weight boilers.