water tube boiler

What is Water tube boiler on ship? | Construction | Working of water tube boiler |

A water tube boiler is a type of boiler where water circulation takes place inside the tube surrounded by exhaust gas or hot flue gasses coming from the combustion chamber.

water tube boiler


According to the diagram we have two drums, one is a Steam drum and the other is a Water drum connected by the tube stacks (lots of tubes are together to connect the drums called tube stacks).

In the water drum, we have water and in the steam drum, we have steam being produced. A combustion chamber is placed between both drums, a source of heat energy for this boiler.

Basic layout of water tube boiler

Fig: Basic layout of water tube boiler


When water is getting heated its temperature increases and density decreases. For example, take a bucket of water and put the geyser water inside that bucket, the moment that you put your hand inside the bucket at the top you feel it is hot and when you put your hand deep inside the bucket at the bottom you feel it is a bit cold. Because of the density difference normal water (denser) remains down while hot water (less dense) comes up.

Here also in this type of boiler, all the water inside the tube is not at the same temperature. The difference in temperature of the water inside the tube causes the density difference due to which colder water flows down from the steam drum to the water drum and hot water flows up from the water drum to the steam drum (the natural circulation of water takes place). Since the Natural Circulation of water takes place, better evaporation will occur with the help of heat application (hot flue gasses from a Combustion Chamber) and faster steam production takes place.

Advantages of Water Tube Boiler:

  1. Generate a large amount of steam.
  2. Can handle pressure up to 350 bar. (Thermal Power Plant).

Disadvantages of Water Tube Boiler:

  1. Expensive compared to other boilers.
  2. High Maintenance is required.


If you want to learn more about this topic, we suggest checking out our Combo package with the given link https://www.merchantnavydecoded.com/courses/c/ . It’s a great way to dive deeper into the subject through video explanations. This package covers all the important details and presents them in an easy-to-understand format. Watching the videos will help you grasp the topic better and make learning more enjoyable. So, we highly recommend giving our Combo package a try to enhance your knowledge on the subject.

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