What type of furnace is surrounded by brickwork rather than by water?

In a furnace design, the distinction between internally fired and externally fired furnaces primarily relates to how heat is generated and contained. An externally fired furnace is constructed in such a way that the combustion takes place outside the furnace itself and the heat is transferred to the system via the surrounding structure, which can be in the form of brickwork or metal.

In this context, the externally fired furnace utilizes brickwork to contain and conduct heat, rather than employing a water jacket as seen in other designs. The brickwork effectively absorbs and radiates heat from the flames or other heat sources located outside the combustion chamber, thus providing energy to the heating process. This configuration can lead to efficient heat transfer and better control of temperatures within the furnace.

Other types of furnaces, such as internally fired and staged combustion, incorporate different designs and methods for thermal management and heat transfer, which do not involve being surrounded by brickwork but rather involve direct heat generation within a specific vessel or chamber. Understanding these differences is crucial in selecting the appropriate furnace type for specific applications and ensuring efficient operation.