working principle of Cochran boiler in Telugu lecture

Cochran boiler is a vertical , internally fired, natural circulation fire tube boiler. Boiler may be coal fired or oil fired.
The boiler is filled with water to a specified level. The flue tubes are completely submerged in the water. The coal is introduced through the fire door on to the grate. In oil fired boiler, the oil is directly sprayed into the furnace. Fuel is burnt in the fire box and the hot gases from the fire box pass to the combustion chamber they pass through a short flue pipe.
from the combustion chamber they pass through horizontal fire tubes to the smoke box and from there the gases are discharged to the atmosphere through the chimney. They hot gases while passing through the fire tubes transfer their heat to surrounding water. The water may also receive heat from the fire box directly. The water is evaporated to form steam. The steam formed is accumulated in the steam space. It is allowed to flow through the steam stop valve to the steam supply pipe.
this question is very important for diploma mechanical, electrical ,civil students and also b;.tech students.