A dome or dome furnace is a fusion device used in foundries that can be used to smelt cast iron, Ni-resist iron and some bronzes. The dome can be made almost any practical size. The size of a dome is expressed in diameters and can range from 1.5 to 13 feet (0.5 to 4.0 m). The general shape is cylindrical and the equipment is vertically arranged, usually supported by four legs. The overall look is similar to a large fireplace.
The lower part of the cylinder is equipped with doors that rotate downwards and outwards to "drop down". The top where the gases escape can be open or equipped with a cap to prevent rain from entering the dome. To control emissions, a dome can be equipped with a cap that is designed to pull the gases in a device to cool the gases and remove the particles.
The shell of the dome, generally made of steel, has refractory brick and plastic refractory patch material covering it. The bottom is coated in a similar manner, but often a mixture of clay and sand ("bod") can be used, since this coating is temporary. The finely divided charcoal ("sea char") can be mixed with the clay coating so that when the coal is heated it decomposes and the body becomes slightly friable, facilitating the opening of the faucet holes. The lower liner is compressed or knocked against the lower doors. Some domes are equipped with cooling jackets to keep the sides cool and with oxygen injection to make the coke fire burn hotter.