In a Dryback Boiler, what directs the gases of combustion?

In a Dryback Boiler, the gases of combustion are directed primarily by the refractory lined chamber. This chamber serves a crucial function by shaping and containing the combustion process, ensuring that hot gases are channeled efficiently. The refractory lining helps to withstand high temperatures and reflects heat back into the combustion area, facilitating better combustion and heat transfer.

The design of the refractory lined chamber is specifically tailored to guide these gases through the boiler system, maximizing contact with the heat exchange surfaces. This enhances the efficiency of heat transfer from the combustion gases to the water or steam circulating through the system.

The other components mentioned have their respective roles, but they do not specifically focus on directing the gases of combustion as effectively as the refractory lined chamber does. For instance, the combustion chamber is where the fuel burns but doesn’t specifically direct the flow of gases; the draft fan assists in creating a flow of air and gases but does not contain or direct them; and the heat exchanger is involved in transferring heat rather than controlling gas flow direction. Thus, the refractory lined chamber is the key element that directs the flow of gases within a Dryback Boiler.