Cochran Boiler: Components And Working Principle

In this article, I will share the overview, components and working principle of Cochran boiler.


This is a fire tube boiler since the combustion gasses are passed through tubes to heat the water in the boiler.


It’s a vertical boiler which makes it easier to be placed in a power plant that has limited space.


This boiler can be designed with a diameter of 2 to 3 metres and a height of upto 6 metres.


The size of the boiler to be selected will mainly depend on the capacity of steam that is needed from the boiler.


You might like this: 10 Factors To Consider When Choosing a Boiler


The chochran boiler has its limit. The maximum evaporative capacity (steam generation) is 4730 kg at 1000C per hour.


If you want a boiler with an evaporative more than this, you will have no choice but to select another type of a boiler.


The main advantages of using Cochran boilers are that they require small space because of their vertical design and they are compact.


When the boiler is compact it design it reduces the installation hassles, more steam distribution lines are reduced and it becomes easier to maintain such kind of a boiler.


In vertical boilers, the heating surface ratio is about 10 to 25, and a steam pressure of about up 10kg/cm2 can be achieved.


Now that you have an overview of how the boiler is, it’s time to share the components of the boiler.


Components of Cochran boiler.

These are some of the essential components of Cochran boiler;

  1. Fire box
  2. Combustion chamber
  3. The shell
  4. Fire brick lining
  5. Man hole
  6. Stack
  7. Smoke box
  8. Steam stop valve
  9. Steam space


Fire box

It’s where the fuel is burnt. The fire box contains the grate too that carries the fuel to be burnt.


Combustion chamber

It’s where the combustion gasses from the fire box are brought first before directed to the fire tube.


Fire tubes

They are used to pass the combustion gasses thus transferring heat to the water in the shell.


The shell

It holds the boiler water and allows the passage of fire tube to allow heat transfer.


Fire brick lining

It’s located in the combustion chamber; it’s used to prevent heat losses from the combustion chamber and prevent the damaging of the shell by extreme temperatures.


You might like this: Type Of Heat Losses In a Steam Plant (+How To Minimize Them)


Man hole

It’s located on the top side of the shell, it’s provides an access to clean and maintain the boiler when necessary.



It’s used to allow the flue gasses out of the boiler shell to the atmosphere.


Smoke box

It’s used to clean the flue gasses that are about to released out to the atmosphere via the stack.


Steam stop valve

It’s used to release the steam from the shell and convey it to the point of application.


Steam space

It’s where the steam generated is collected before it’s removed out of the shell via the steam stop valve.


These are just some of the components of Cochran boiler, but there are many more mounting and accessories.


Now that you know a little bit of the components, let us now talk about the working principle of this boiler.


Working principle of Cochran boiler.

The working principle of Cochran boiler is just like the typical fire tube boilers.


The fuel is burnt in the fire box, the combustion gasses are directed to the combustion chamber then to the fire tubes. The fire tubes are passed around the water in the shell to be heated.


The water is then converted into steam and enters the steam space where it’s then released out of the shell fire the steam stop valve.


After the combustion gasses have been used to heat up the water in the shell, they are directed to the smoke box to be cleaned then released out of the boiler shell via the stack.


The safety valves are used to regulate the steam pressure to prevent the shell from exploding when the pressure is too high in the shell.


That’s the simple working principle of Cochran boiler, there is nothing complicated about this type of boiler.


It’s just simple and compact in design.




This is just a summary of Cochran boiler and its working principle. There is still more to learn about this boiler.


I tried to summarize and simplify according to my own understanding. If you have an additional point or suggestion, feel free to leave a comment.


For you to understand the effectiveness and efficiency of this type of boiler you have to dig deeper and ask some of the power plants that use this type of boiler before you consider installing it in a power plant.


You have to understand that different types of boiler will work different in different plants depending on the processes being carried out.


Thanks for reading, see you in my next article.


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