The dictionary defines a cupola as a domed roof, a gun turret or a vertical cylindrical Furnace to melt metal to further refine it in other furnaces, or to cast it into useful shapes. The editors of Encyclopedia Britannica claim that René-Antoine Ferchault de Réaumur built the first cupola furnace on record, in france, About 1720. Cupola melting is still recognized by some as the most economical melting process if the furnace is operated continuously. A lot of grey iron is still melted and cast by this method. Improvements in the process over the last 200 years have included the construction of the larger furnaces and the application of the heated air at the tuyeres. Many foundries however as we shall see have invested in other more modern furnace designs and INSERTEC are able to supply a complete range of refractory lining products for all.
Cupolas were traditionally lined with brick but in the last 50 years many of these units and other vertical shaft furnaces have switched to monolithic linings because the quality and availability of monolithic refractories have improved enormously and they are more cost effective when properly engineered and expertly installed.
At the top of the furnace the refractories must resist mechanical and thermal shock while in the lower part of the lining the most important properties are the ability to resist attack from molten metal and slag at elevated temperature. Intermittently operated furnaces are sometimes cleaned and given a protective wash on the hot face each day but continuously operated units must be constructed from premium products for long life and low cost.
INSERTEC, have a complete range of monolithics for the original linings of both ferrous and non ferrous furnaces of all sizes and you are invited to contact us for precise recommendations.
For economic and operational reasons many ferrous and nonferrous foundries have more recently invested in crucible and induction furnaces for melting and casting their products.
Crucible furnaces are one of the oldest and also one of the simplest types of melting unit used in a foundry where small batches of low melting point metal or alloys are required. The charge is placed in a refractory crucible and heated mainly by conduction through the walls of the crucible using gas oil or electricity as the fuel. Most modern foundries however use electric induction furnaces for the efficient melting of both ferrous and non ferrous metals and alloys and these have largely now replaced crucible furnaces especially for elting of high melting point alloys such as cast iron and steel. Induction furnaces are generally easier to control with regard to temperature and chemistry and better suited to the enviorement.
Written by Eate From U.K.