Model of Cochran Boiler:The model is the best known vertical type fire tube boiler. The shell is about 25 cm. in diameter and 60 cm, high. The cylindrical fire box is with a door and grate at its bottom. Hot gasses pass from the fuel to the combustion chamber through a short flue pipe and then to chimney through the tubes. At both ends of the tubes covers are given and tubes can be cleaned after their removal. The model is complete with feed check valve, steam and water gauges, stop valve, safety valve and manhole.