TYPES OF BOILER:
Different types of boiler used in various industries for different purposes. Types of boiler depending on boiler capacity, steam pressure, and other parameters. Here types of Boilers can be classified as:
1. Types of Boiler according to contents in the tube:
- Fire tube boiler
- Water tube boiler
Fire tube boiler: In this type of boilers, flames and hot gasses produced by combustion of fuel passes through the tubes while water flowing outside the tubes.
Example: Simple Vertical Boiler, Cochran Boiler, Lancashire Boiler, Scotch Marine Boiler, Velcon Boiler, Cornish Boiler, and Locomotive Boilers are the examples of Fire Tube Boiler.
Water tube boiler: In Water tube boilers, water flowing inside the tubes (water tube) while flames and hot gasses surrounded outside the tubes.
Example: Stirling Boiler, La-Mont Boiler, Benson Boiler, Yarrow Boiler, Babcock and Wilcox Boilers are the examples of Water tube boilers.
2. Types of Boiler according to the position of the furnace:
- Internally fired boiler
- Externally fired boiler
Internally fired boiler: Boilers in which furnace locates inside the boiler shell, are internally fire boilers. Most of the fire tube boilers are internally fire.
Externally fired boiler: Boilers in which furnace is located outside the boiler shell are called externally fired boilers. Water tube boilers are always externally fire.
3. Types of Boiler according to the axis of the shell:
- Vertical boilers
- Horizontal boilers
Vertical boilers: Boilers having a vertical axis of the shell are called vertical boilers. Simple vertical boiler and Cochran boilers are examples of vertical boilers.
Horizontal boilers: In this type of boilers, the axis of the shell is horizontal. Lancashire Boiler, Locomotive Boiler, and Babcock and Wilcox Boilers are Horizontal Boilers.
4. Types of Boiler according to the number of tubes:
- Single tube boiler
- Multitubular boiler
Single tube boiler: In Single tube boilers, there is only one water tube or fire tube. Cornish Boiler and simple vertical boilers are single tube boilers.
Multitubular boiler: Boilers having two or more water tubes or fire tubes are called Mulitubuler boiler. Lancashire Boiler, Locomotive Boiler, and Babcock and Wilcox Boiler and Cochran boilers are Mulitubuler Boilers.
5. Types of Boiler according to the method of circulation of water and steam:
- Natural circulation boilers
- Forced circulation boilers
Natural circulation boilers: In natural circulation, the circulation of water is natural convection, which is produced during the heating of water. Most of the steam boilers are natural circulation.
Forced circulation boilers: In forced circulation, the circulation of water is produced through the centrifugal pump. Forced circulation used in high-pressure boilers such as Benson Boiler, Loeffler boiler, and Velcon boiler.
6. Types of Boiler according to the Pressure of steam:
Boilers can also be classified as:
- Low-Pressure Boilers
- High-Pressure Boilers
Low-pressure boilers operating steam pressure not exceeded 1.021 atm (103.427KN/m2) and operating pressures of hot gases bot exceeding 10.893 atm (1.10MN/m2) and temperature 394k degree.
7. Types of Boiler according to Mode of firing:
- Fired Boilers
- Non-Fired Boilers
Fired Boilers: In this type of boiler, supplied heat comes from the combustion of fuels.
Non-Fired Boilers: Non-Fired Boiler receives heat other than that produced by the burning of fuel.
8. Types of Boiler according to the type of fuel:
On the basis of fuel, a boiler is designed by the nature of fuel used.
- Coal Fired
- Gas Fired
- Oil Fired
- Wood Fired
- Bagasse or Rice husk straw-fired
9. Types of Boiler according to the use:
- Stationary boilers
- Mobile boilers
Stationary boilers: These Boilers do not move from one place to another place. Boilers used in power plants and other industrial process work are stationary boilers.
Mobile boilers: Boilers move from one place to another place, called Mobile Boilers. Locomotive and Marine boilers are the best examples of Mobile boilers.
10. Types of Boiler according to the source of heat:
Boilers can also be classified according to the source of heat supplied for producing steam. These sources are:
Source of combustion (solid, liquid or gaseous fuels)
Electrical energy / nuclear energy / Geothermal Energy