Vuurbox

Vuurbox, Dutch for firebox, is the enclosed chamber in a furnace, boiler, or steam locomotive where combustion of fuel takes place. The design and integrity of the vuurbox are central to the efficiency and safety of the system, since heat produced inside it is transferred to the surrounding heat exchanger, such as boiler water or steam cylinders.

Construction typically features heat-resistant lining, such as firebrick or ceramic material, and a reinforced metal shell. The firebox sits downstream of the grate and upstream of the boiler tubes or flues. A grate and ashpan collect combustion residues, while a brick arch or similar construction promotes stable, even combustion. Air is supplied through dampers and primary/secondary air pathways, helping to regulate flame temperature and fuel use.

Vuurbox designs vary by fuel type and application. In coal-fired boilers and steam engines, the firebox is relatively large and rugged, with a robust door for stokers. Oil- or gas-fired fireboxes use different burners and may employ sealed combustion. In residential and industrial boilers, compact fireboxes are paired with heat exchangers to optimize heat transfer and minimize emissions.

Historically, vuurbox technology was essential to the rise of steam power in the 19th and early 20th centuries. With the decline of steam propulsion, the firebox remains a key element in many traditional boilers and in modern high-efficiency units, where it is integrated with advanced control systems for safety and performance.