Lancashire Boiler: Components And Working Principle

In this article, I will share the components and working principles of the Lancashire boiler.


This boiler has a unique design but its working principle is just like the rest of the boilers.


It has a fire hole where the fuel is fed through and the combustion gasses produced are released moving around the boiler shell heating the water surrounding the furnace.


The design of the furnaces being surrounded by water is to ensure that maximum heat transfer happens before the flue gasses are released into the atmosphere.


The fire tube has a diameter of about 1 metre, but that is not throughout the entire length of the fire tube; at the begging of the fire tube, the diameter is larger while at the rear end, it gets smaller.


This fire tube design has several advantages to the Lancashire boiler; it’s not just for show.


The diameter of the fire tube is larger at the beginning to allow the fire hole to be able to feed a large quantity of fuel and allow enough air to enter the tube for enough heat generation and the diameter being smaller at the rear end is to allow the combustion gasses to be released out of the fire tube with pressure and higher velocity.


The boiler shell is the central part that holds the boiler water to be generated into steam.


This shell is supported by brick walls around it to ensure that it’s held in place and also the brick wall gives a clear path of where the combustion gasses can pass through while heating up the water in the shell.


The flue gasses pass all sides of the boiler shell to ensure maximum heat transfer before being released into the atmosphere.


Lancashire boilers are usually constructed and designed to generate steam pressure of about 17.5kg/cm2 and with an evaporation capacity of 8300 kg per hour.


Compare to most boilers, the Lancashire boiler has a great evaporation capacity of kg per hour thus making it a very capable boiler in large industries and power plants.


Components of Lancashire boiler

These are some of the main components of the Lancashire boiler;

  1. Fire tube
  2. Firebox
  3. Boiler shell
  4. Brick walls
  5. Manhole
  6. Safety valve


Fire tube

This is the part of the tube that combustion gasses are released from and moved around the boiler shell to heat the water.


It has a fire hole through where the fuel is fed for burning to happen for the combustion gasses to be produced.



This is where fuel combustion takes place and the combustion gasses are taken to the fire tube and moved around the boiler shell.


Boiler shell

This is the part of the boiler that holds the boiler water that is to be generated into steam.


The boiler shell also leaves room for steam collection above the water level.


So, it’s a very important part of the boiler and that is why it’s supported by brick walls to hold it into place.


Brick walls

The brick walls built around the boiler are important for keeping the boiler shell supported and also prevent heat losses out of the boiler.


This ensures that the boiler shell uses the flue gasses to maximize heat transfer.



It’s an opening that provides access to clean the boiler to enhance its efficiency.


Safety valve

It’s used to control the steam pressure of the boiler thus preventing it from exploding under extreme pressure and temperature.


It’s mainly for safety purposes when there is a need to quickly reduce the steam pressure if the main control panel is not working.


Working principle of Lancashire boiler

The fuel is fed into the fire tube through the fire hole. Combustion of the fuel takes place in the firebox.


The combustion gasses are then released out of the firebox and through the fire tube first and then distributed to the bottom and top of the boiler shell after they have left the fire tube.


The fire tube is surrounded by water that is in the boiler shell to maximize heat transfer.


The steam generated collects in the boiler shell beyond the level of water then released out of the boiler via the steam stop valve.


The flue gasses are also released out of the boiler and used in other accessories like the Sugden superheater, boiler economizer and air preheater to ensure that heat losses are minimized.


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


And that is how simple the working principle of the Lancashire boiler is.




This is just a summary of the working principle of the Lancashire boiler.


This boiler is preferred in some power plants and industries because of its large evaporation capacity.


There is much to learn about the design and how effective it’s in different types of industries.


You will have to dig deeper if you want to learn more about its construction and how effective it can be.


This kind of boiler is vast and requires a large space for installation.


The Sugden superheater is used to ensure that the steam is of the required quality.


You might like this: Advantages Of Using Superheated Steam


Thanks for reading, if you have any additional points or questions about this type of boiler, just leave your comment. See you in my next piece.


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