Boilers

A boiler (or steam generator, as it is commonly called) is a closed vessel in which water, under pressure is transform into steam by the application of heat. Open vessels and those generating steam at atmospheric pressure are not considered to be boilers.

 In the furnace the chemical energy in the fuel is converted into heat, and it is the function of the boiler to transfer this heat to the water in the most efficient manner. thus the primary function of a boiler is to generate steam at pressure above atmospheric by the absorption of heat that is produced in the combustion of fuel .

A boiler should be designed to absorb the maximum amount of heat released in the process of combustion. This heat is transmitted to the boiler by radiation, conduction, and convection, the percentage of each depending on the boiler design. 

Boiler types :

1) Fire-tube boilers : are so named because the product of combustion pass through tubes that are surrounded by water. They may be either internally fired or externally fired. 

2) Water-tube boilers :is one in which the products of combustion pass around tubes containing water.

3) package boiler