Comprises of a water drum which is connected to two headers at the front and back ends. The headers are connected by large number of water tubes which is inclined upwards from down take header to uptake header. Furthermore, a mud drum, in which heavier sediments of water settle down and are blown off from the blow off pipe, is provided. The combustion chamber is located below the boiler drum. A chain grate with the stoker is provided from burning coal. Hot flue gasses which are produced after combustion of fuel are made to pass over the water tubes in several passes with the help of baffles. The draught is regulated using dampers provided. Lastly, chimney is provided to permit exit of waste flue gasses.
A super heater is provided to superheat dry and saturated steam. It comprises of U tubes and is placed in path of flue gasses.
A number of mountings which ensure safe and efficient operation of boiler are also provided. These include water level indicator, Dead weight safety valve, Pressure Gauge etc.