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The Lancashire boiler is one of the famous types of fire tube boilers. It is a natural circulation boiler. This article explains the Lancashire boiler working, components, and applications.
What is a Lancashire Boiler?
The Lancashire boiler is an internally fired, natural circulation fire tube boiler. In the Lancashire boiler, the heat transfer process occurs through convection from the exhaust gases to the water.
The heat exchange principle is the working principle of the Lancashire boiler. It was invented by William Fairbairn in 1844.
In this type of fire tube boiler, the natural circulation method is used to circulate the water into the tubes. It is an internally fired boiler. The steam produced by this boiler has low pressure.
It contains a huge cylindrical shell with two flue tubes. In the boiler shell, the furnace is placed at one end, and on the other end, a chimney is present that is used to discharge the flue gases out of the boiler. This shell is partially filled with water, and the water inside the shell is heated by the hot flue gases circulating into the flue tubes.
The efficiency of the Lancashire boiler is between 80% and 90%. Its length is about 7 to 9 meters, and its diameter is 2 to 3 meters. Lancashire boilers are most commonly used for locomotive and marine engines.
Working of Lancashire Boiler
The heat exchanger principle is used in the Lancashire boiler. It is a shell-and-tube heat exchanger. In this boiler, the flue gases circulate through the tubes while water circulates into the shell.
The Lancashire boiler works in the following ways:
- The feed pump pumps the water into the economizer.
- The water gets a little heat from the economizer through the flue gases.
- This preheated water is then brought to the shell of the boiler.
- The coal starts to burn as soon as the water enters the boiler.
- With coal burning, heat is produced that transforms into flue gases.
- The temperature of the flue gases increases, and they begin to circulate in the tubes. These tubes are submerged in the water.
- A small brick arc is present in the boiler that stops the ashes produced by the burning coal from entering the boiler.
- With the circulation of the hot flue gases into the tubes, the tubes get heated, and the heat begins to transfer from the surface of the tube to the water.
- About 80 to 90 percent of the heat is transferred into the water through these tubes.
- With the increase in temperature, the water converts into steam.
- This steam is then forwarded to the superheater, which further increases the temperature of the steam.
- The stop valve then transfers the steam to the desired places.
- These heated flue gases pass back through the tube that is contacted by the shell. The heat is again transferred to the water and increases its temperature; this heating increases the efficiency of the boiler.
- These flue gases then leave the boiler and enter the atmosphere through the chimney.
Components of the Lancashire Boiler
- Fire door
- Air preheater
- Manhole
- Safety valve
- Steam stop valve
- Economizer
- Feed pump
- Ash pit
- Blow off valve
- Pressure Gauge
- Water Level Indicator
- Superheater
- Fusible Plug
- Shell
- Feed check valve
1) Pressure Gauge
A pressure gauge records the readings of the steam pressure in the boiler. It indicates the pressure value whenever the steam pressure inside the boiler reaches the maximum and minimum levels.
2) Safety Valve
It protects the boiler from bursting. It performs this job by releasing the excessive steam pressure when the internal steam pressure of the boiler increases above its optimal pressure.
3) Water Level Indicator
The water level indicator is an external part of the boiler. It assists in controlling the water flow inside the boiler. It records the water level inside the boiler. When the water level becomes lower than a specified limit, the water level indicator sends a signal to the feed pump to pump more water to the boiler.
4) Shell
The shell is one of the major components of the Lancashire boiler. It is an external part of the boiler. It has a cylindrical shape. It surrounds all the internal parts of the boiler and prevents them from damage to the external element.
5) Blow-off Valve
It uses to expel the waste and mud gathered at the boiler’s base. These sediments must be eliminated over time because they can create operational hurdles.
6) Fire Door
From the fire door, the solid fuel is burned to produce heat which is transformed into the flue gases. The solid fuel is combusted using this fire door.
7) Stop Valve
The main function of the steam stop valve is to prevent steam from entering the delivery pipe. When the steam is not needed in the system, this valve is turned off to cut the delivery of the steam to the system.
8) Feed Check Valve
It controls the flow of water into the boiler and doesn’t allow the backflow of water from the boiler to the pump.
9) Fusible Plug
The fusible plug is also known as a fusible valve. It works the same as the safety valve and prevents the boiler from bursting. It serves as the safety valve’s backup precaution. The main function of the fusible valve is to expel excessive steam from the boiler and prevent it from busting.
10) Economizer
It is an external mechanical part of the Lancashire boiler. It helps to improve the efficiency of your boiler. It preheats the water through the residual heat of the flue gases.
11) Ash Pit
All the unburned fuel and the ashes are collected in the ash pit. The unburned fuel and the ash are brought into the ash pit using the grate.
12) Manhole
The manhole is one of the most vital components of the Lancashire boiler. It is also an external component of the boiler. It is the passage made for the workers to enter the boiler. This opening is used to repair and clean the boiler from the inside.
13) Superheater
It raises the temperature of the steam and ensures that there are no water particles in the steam. It converts the saturated steam into supersaturated steam. It uses the heat of the flue gases to convert the saturated steam into a supersaturated phase.
14) Air Preheater
The working of the air preheater is very same as the economizer. It also assists in improving the efficiency of the boiler. The air preheater takes the air from the atmosphere, preheats it, and then sends it to the furnace.
Read More: Lamont Boiler Working and Applications
Advantages of Lancashire Boiler
- Lancashire boilers have the ability to generate a huge amount of steam.
- Good capacity for fulfilling the load requirements easily.
- These boilers have thermally efficient from about 80% to 90%.
- Easy to operate.
- Easy to inspect and clean.
- Highly reliable.
- They need very low maintenance.
- These types of boilers consume less electricity because they are natural circulation boilers.
Disadvantages of Lancashire Boiler
- The Lancashire boiler has corrosion issues.
- These boilers need more installation area.
- It only generates low-pressure steam.
- The size of this boiler is very large.
- Improper grate area due to small flue tubes.
- It has leakage problems.
- They need more time to produce heat.
Applications of Lancashire Boilers
- Food and beverage industry: The Lancashire boiler is used in the food and beverage industries in the processes of pasteurizing, sterilizing, and cooking.
- Textile Industries: They are used in textile mills. The stream generated by these boilers is used in several processes, like spinning, weaving, and dyeing.
- Paper Industry: The steam taken from the Lancashire boiler is used in dyeing and finishing.
- Power Generation: Lancashire boilers are used to produce electricity in the power plants.
- Chemical Industry: Distillation, chemical reactions, and evaporation processes in the chemical industry are carried out by the steam of the Lancashire boiler.
Difference between the Lancashire Boiler and Cornish Boiler
| Lancashire Boiler | Cornish Boiler |
| The Lancashire boiler has two fire tubes running through the length of the boiler. | It has only one large fire tube. |
| It has the ability to operate at higher pressures. | It can’t operate at higher pressure. |
| It is larger than a Cornish boiler. | It is smaller in size than Lancashire boilers |
| It has low thermal efficiency than the Cornish boiler. | It has higher thermal efficiency due to better heat transfer |
| These boilers are used for larger industrial applications such as powering steam turbines. | These are usually used for powering small steam engines. |
FAQ Section
What is Lancashire Boiler?
The Lancashire boiler is an internally fired, natural circulation fire tube boiler. In this boiler, the heat transfer process occurs through convection from the exhaust gases to the water.
How many numbers of flue tubes in the Lancashire boiler are?
The Lancashire boiler has two flue tubes.
Where is Lancashire boiler used?
Lancashire boilers are used in power plants where a steam turbine is used to generate electricity.
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