In a water tube boiler, where do the gases of combustion pass?

In a water tube boiler, the design principle involves the combustion gases passing around the outside of the water-filled tubes. This configuration allows for efficient heat transfer, as the hot gases come into contact with the tube surfaces, transferring heat to the water inside. The water in the tubes absorbs this heat, causing it to turn into steam.

This method of circulation is advantageous because it reduces the risk of overheating and provides a controlled environment for steam generation. The use of water inside the tubes is a core characteristic of water tube boilers, making them suitable for producing high-pressure steam. Other designs, like fire tube boilers, have combustion gases passing through tubes that are surrounded by water, which is a key distinction.

Overall, the flow of combustion gases around the tubes is critical for the efficient operation and performance of the water tube boiler.