Cornish Boiler | Working, Parts, Applications and More |

I’ll talk about Cornish Boiler today.

If you’re seeking for a concise description of this boiler, you’ve come to the right place. Here, you’ll learn everything there is to know about this boiler.

As a result, I kindly ask you to go on this intellectual adventure with me, and I sincerely hope that this will put an end to your search.

So without wasting much time, allow me to begin this educational adventure with you.

So let’s get started.

Cornish Boiler-

Cornish Boiler is a fire tube, horizontal, internally fired, natural circulation boiler just like Lancashire boiler except having a single large fire tube instead of two fire tubes in the Lancashire boiler.

Firstly, This boiler was initiated by Richard Trevithick and installed at the Dolcoath mine in 1812.

Cornish boiler can produce steam at the rate of 6500kg/hr with a maximum steam pressure of 11bar.

Now, Let’s head on to the cornish boiler construction and working section.

So, Here we go…

Construction of Cornish Boiler-

Here are some main parts or Boiler’s Mounting and Accessories with its construction-

  1. Manhole
  2. Safety Valve
  3. Flue tube
  4. Grate
  5. Blow-off cock
  6. Stop valve


A manhole is basically used for cleaning and maintenance of the boiler, located on top of the boiler.

Safety Valve-

This device is used to protect the boiler from excess steam generation and explosions, located on top of the boiler.

Flue tube-

A flue tube is used to supply the solid fuel into the boiler located front side of the boiler.


As you know, the grate is made of cast steel bar and basically used to hold the solid fuel located inside the flue tube or firebox, located in front of the boiler.

Blow-off cock-

This device is used to drain out the boiler water when needed. It is located at the front bottom side of the boiler.

Stop valve-

The function of the stop valve is to regulate and supply the saturated steam in further directions and it is located at the top of the boiler.

Cornish boiler diagram-

cornish boiler diagram

Now let’s talk about the placement of these parts of this boiler-

First of all the manhole is located at the top of the boiler with a safety valve also located at the top(shown in the figure above). Here the flue tube is located at the front side of the boiler and the grate is also located at the same as the flue tube.

Now it’s time for the Blow-off cock and stop valve, One is located at the front bottom side of the boiler and the other is located top of this boiler.

Working Principle of Cornish Boiler-

When solid fuel or coal is burnt inside the fire door of the combustion chamber, these hot gases or flue gases will generate and this will travel into a single large fire tube.

This fire tube is surrounded by the water and hence these hot gases will exchange heat with water, this exchange of this heat will cause heat up the water.

Heated water will now convert into steam after reaching the boiling point.

This generated and saturated steam will subside at the top of the boiler shell.

Now, again hot gases will travel from the fire tube and exits from the side flue corner and again heat up the water from the side to raise the efficiency of the boiler and maximum utilization of the hot gases, as you can see in the diagram.

Again these hot gases travel into the bottom flue corner to exit from the chimney.

Thus, generated steam will be now going to the stop valve, where this saturated steam will further sent to the superheater to superheat the steam and further taken out for use.

This is how this works.

Now, Let’s move on to the cornish boiler advantages and disadvantages section, where I will discuss the same for this boiler. So, Here we go…

Advantages of Cornish Boiler-

Here are some advantages of this boiler-

  1. Simple Design
  2. High thermal efficiency
  3. Flexible and Portable
  4. Economical

Disadvantages of Cornish Boiler-

Here are some disadvantages of this boiler-

  1. Low-pressure boiler
  2. Large spacing required
  3. Low steam rate production

Applications of Cornish Boiler-

Here are some disadvantages of this boiler-

  1. Sugar mills
  2. Chemical industries
  3. Steam turbine
  4. Marines
  5. Thermal Power generation

Difference between Cornish and Lancashire Boiler-

The difference between cornish boiler and Lancashire boiler is

Shape and Size:

    • Cornish Boiler: Imagine a long, horizontal cylinder. That’s a Cornish boiler. It’s a bit like a stretched-out barrel lying on its side.
    • Lancashire Boiler: Now picture a big, fat drum. That’s a Lancashire boiler. It looks like a chubby barrel standing upright.

Flue Tubes:

    • Cornish Boiler: It has just one big flue tube where hot gases go.
    • Lancashire Boiler: It has two flue tubes, one at the back and one at the front. Double the tubes for double the fun.

Hot Gases Journey:

    • Cornish Boiler: Hot gases take a single journey through the one flue tube. It’s a direct route.
    • Lancashire Boiler: Hot gases have a longer journey. They go through one flue tube, then into the combustion chamber, and finally through the second flue tube. It’s a bit like a scenic route.


    • Cornish Boiler: It’s good for small places and works well when you need a steady supply of steam.
    • Lancashire Boiler: It’s bigger and more powerful, suitable for industries that need lots of steam, like factories with big machines.

Use of Space:

    • Cornish Boiler: It’s compact and takes up less space horizontally.
    • Lancashire Boiler: It’s bulkier but can handle larger amounts of water and steam. It’s a bit like comparing a small car to a big truck.

So, in a nutshell, Cornish boilers are like the stretched-out cylinders for simpler needs, while Lancashire boilers are the bigger, double-tubed workhorses for larger industrial tasks.

Here is the Video Guide to Inform you out even more-


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Before you go, Here are your freebies all yours-

Cornish boiler ppt
 cornish boiler ppt

Cornish boiler pdf
Cornish boiler pdf


Before you leave, here are some related questions and its answer, you should have a look for while-


What is the efficiency of the cornish boiler?

It has a steam capacity of 6500kg/hr with a maximum working pressure of 11bar. This is the overall efficiency of the cornish boiler.

The number of water tubes in a cornish boiler?

There is a single large fire tube in the cornish boiler. There is no water tube present in this boiler.

The cornish boiler is an example of which type of boiler?

Cornish boiler is a suitable example of a fire tube boiler.

How many fire tubes are there in the Cornish boiler?

There is only one fire tube in this boiler that is internally fired.

What is the steam capacity of a Cornish boiler?

The steam capacity of this boiler is 6500kg/h.

Is Cornish boiler a low-pressure boiler?

Yes, this boiler is a low-pressure boiler but it has high thermal efficiency.

What is the pH value of water permissible for the boiler?

The pH value of water permissible for the boiler ranges from 8.4 to 8.5pH.

What chemicals are used in boilers?

Sodium hydroxide and potassium hydroxide, are the chemicals used in boilers.

How many fire tubes are available in Cornish boiler?

A single fire tube is present in the cornish boiler.

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