Understanding the Different Types of Boilers

Boilers are a crucial part of various factories and plants, especially power generation plants. They form the crux of the operations required for power generation. Boilers are closed vessels that are used to convert water into high-pressure steam. The steam, in turn, is used for generating power as the steam rotates the turbines.

Boilers may look and feel the same, but that is not the case. If you are associated with working at a place involving boilers, it is essential that you know the different types of boilers. Knowing boilers is essential to ensure that you can work and operate boilers effectively. Similarly, in case of breakdowns, you can provide the correct information to a boiler breakdown services provider beforehand on the call that can help make the repair process simpler and faster.

In this blog, we have discussed the various types of boilers and classified them according to various parameters.

Furnace Position

Depending upon the position of the furnace, boilers can be classified into external-fired boilers and internal-fired boilers.


These boilers, as the name suggests, have their furnace located outside the boiler shell. External-fired furnaces are arranged underneath in brickwork settings. The most common type of external-fired boiler is the water tube boiler.


Conversely, internal-fired boilers have their furnace located inside the boiler shell. Most of the fire tube boilers that are used commercially are internal-fired boilers.

Tube contents

Depending upon the content of the tube, boilers are classified into two main types.


In these types of boilers, the water is used for heating and is present inside the tubes. The fire that is used to heat the water is present outside and surrounds the tubes. Water boilers can be further classified into different types. Some popular water boilers include the Yarrow boiler, Babcock and Wilcox boiler, and Benson boiler.


In these types of boilers, the water surrounds the fire, or hot gases present inside the tubes. The heat is conducted from the inside to the outside through the walls of the tubes. Similar to water-tube boilers, there are different types of fire-tube boilers like the Scotch Marine boiler, Lancashire boiler, and Velcon boiler.

Water and steam circulation methods

Depending on how steam and water is passed in the boiler, they can be classified into two main categories. They are:

Natural circulation

In such boilers, the water is circulated from one part to the other naturally by the convection currents. The currents are set up during the process of heating water. Most boilers have a natural circulation method. Lancashire and Cochran boilers are the types of boilers that have a natural water circulation method.

Forced circulation

In such boilers, the water is circulated from one part to the other with the help of an external machine/device. Generally, a centrifugal pump is used for the water circulation process. Forced circulation is generally used in high-pressure boilers like Benson boiler and La-Mont boiler.

Use case

Depending upon the use case, boilers are classified into two main categories, stationary boilers, and mobile boilers.

Mobile boilers

These boilers can be moved from one place to another. They are designed in a manner that they can be easily transported on trailers and other moving equipment. The boilers include all the necessary parts and pieces of equipment with hook-ups to help assemble and use the boiler with ease.

Stationary boilers

These boilers are permanently attached to a place. Once they are installed, they cannot be moved from one place to another. Such boilers are found in large plants and factories such as power plants and large industrial and metal processing works.

Depending on the use case and other requirements, you can choose any of these types of boiler for your application. If you need help, do not hesitate to call a professional.

Like and Share

Contact Us

Scroll to Top