Working Principle of Cochran Boiler.

Cochran Boiler

The Cochran boiler is also called a fire tube boiler. cochran boiler workes on the principle of heat convection. In cochran boiler, the hot gases are being passed through the fire tube running in the sealed container filled with water. The locomotive boiler is self-propelled and the power is being supplied by the diesel, steam or electricity. This type of steam engine has been used in the railway for a long time. The locomotive boiler is consisting of vertical cylinder shell the top of the cylinder is of dome-shaped. This dome shape provides enough space for steam which is produced on heating. Basically, the water is being heated in a high amount at high temperatures which produce a high amount of steam which is used to do mechanical work. The hemispherically shaped furnace is provided to burn the fuel mostly coal is used. Fuel is kept on the grate to burn the fuel easily and ash is then settled in the ash pit. Fire bricks are used for lining as shown in the figure to overcome with the heat loss. On the burning of the fuel, it produces a large amount of smoke that has to be expelled outside for that chimney is provided. When the heat is generated, it heated the fire tube which is filled with flue gases. this flue gases used to heat the water surrounded by the fire tube. all they are of equal dimensions and is kept in a horizontal position. In this process the coal has to feed periodically to make the heating process continues, fire door is provided to feed the coal periodically. The safety valve is used in an emergency when the steam pressure exceeds its limit then it is being opened to release the excess amount of steam. Flue pipe is provided to heat from the furnace to the combustion chamber.

So many safety kinds of stuff are used in the boiler, a fusible plug is provided at the top of the combustion chamber. When the boiler temperature exceeded the safe working limit then it gets melted and stops the fire. Usually, the fusible plug is made up of aluminium and zinc metal. The blow of cock is used to blow of the impurity, mud and sediment from the boiler.    

To deal with any boiler safety must be the first priority because silly mistakes are enough to destroy the valuable thing even can catch the fire burn the whole plant along with human being.

Cochran boiler

   

Working:

On the burning of the fuel in the furnace, it produces a large amount of heat in the form of flue gases. This flue gases entered in the flue pipe and goes to the combustion chamber. Fire tubes are placed horizontally and it is surrounded by the water completely. Flue gases enter in the fire tube pipe and heated the water and form the steam. Formed steam is being kept in the steam chamber.

To produce the steam water has to supply uniformly to the shell and it is controlled by the feed check valve. When the flue gases supplies boiler heated up and the cold water settled down and steam flow over it between the fire tube. Produced steam is kept in the dome shape chamber on the requirement it is supplied to anti priming pipe where water droplets are filtered. 

Advantages

1. Less floor area is required.
2. Construction cost is less.
3. It can easily move to different locations, semi-portable.
4. It has a self-contained furnace.
5. Easy to operate.
6. Higher volume to areas ratios.

Disadvantage

1. The rate of steam generation is less.
2. Corrosion and scale formation takes place.
3. Overheating problem.
4. Periodic cleaning is required and it is difficult to clean all the parts.

Application

Railway and marine