A fire-tube boiler is a type of boiler invented in 1828 by Mark Seguin, in which hot gases pass from a fire through one or more tubes running through a sealed container of water. The heat of the gases is transferred through the walls of the tubes by thermal conduction, heating the water and ultimately creating steam.
Sectioned fire-tube boiler from a DRB Class 50 locomotive. Hot flue gases created in the firebox (on the left) pass through the tubes in the centre cylindrical section, which is filled with water, to the smokebox and out of the chimney (stack) at far right. The steam collects along the top of the boiler and in the steam dome roughly halfway along the top, where it then flows into the large pipe seen running forward. It is then divided into each side and runs downward in the
Lancashire boiler in Germany
Side-section of a Scotch marine boiler: the arrows show direction of flue gas flow; the combustion chamber is on the right, the smokebox on the left.
Horizontal return tubular boilers from the Staatsbad Bad Steben GmbH
A boiler is a closed vessel in which fluid is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation.
A moveable (mobile) boiler (preserved, Historic Silver Mine in Tarnowskie Góry Poland).
A stationary boiler (United States).
1950s design steam locomotive boiler, from a Victorian Railways J class
A superheated boiler on a steam locomotive