What type of boiler employs a refractory lined chamber for directing combustion gases?

A dryback boiler is designed with a refractory lined chamber for directing combustion gases. This setup allows the combustion gases to pass through an area that is lined with materials resistant to high temperatures, thereby ensuring that the heat is effectively utilized and minimizing the risk of damage from extreme heat. The refractory lining helps withstand the intense conditions created during combustion, directing the gases through the heat exchange area while maximizing thermal efficiency.

In contrast, water tube boilers and firetube boilers utilize different designs for heat transfer and gas flow. Water tube boilers circulate water through tubes to absorb heat produced by combustion, while firetube boilers have hot gases passing through tubes within a water-filled chamber, neither of which specifically involves a refractory lined chamber for gas direction. Sectional boilers, known for their modular design and assembly, also do not incorporate the specific feature of a refractor-lined chamber for guiding combustion gases.