Foundry
A foundry is a factory or workshop for melting and casting metals. A central feature of every foundry is the furnace, although furnace designs have varied over time as technology has advanced. Some types of furnace are better suited to some applications as they all have their advantages and disadvantages.
The cupola furnace has been used to melt cast iron for centuries, however, this design is less widespread today. It consists of a vertical steel chamber with a lining of refractory brick. The charge is formed of layers of metal, coke and flux and is introduced through the side of the chamber about half way up. Hot air enters from below. Molten metal forms on a bed of sand at the bottom and is drawn off with a tap.
In many instances cupolas have been replaced by induction furnaces which generate heat through electromagnetic induction. Large copper coils surround the crucible containing the charge. These furnaces are quicker, cleaner and quieter than traditional cupolas and offer precise temperature control. They can be used for melting a wide range of metals and alloys. However, they do not allow for for any refining and some small quantities of melt may be lost to oxidation.
The reverberatory furnace was once widely used for melting brass, bronze and copper. Now largely superseded, these furnaces are still used for melting scrap aluminium for die casting. The key feature of these furnaces is that the charge does not come into direct contact with the fuel and is melted by radiant heat and convection as the combustion gases pass over the hearth to the flue.
In addition to the furnace, a foundry needs other specialised equipment to handle the molten metal and transfer it to the pouring unit. Vessels for transferring molten metal are called ladles and come in a wide variety of shapes and sizes to meet the needs of small workshops and large scale industrial plants. They are commonly made of steel with a suitable refractory lining. The simplest ladles pour from a lip at the top. Others have a teapot shaped spout or pour from the bottom so that impurities floating on the molten metal are separated. All are designed to maximise efficiency and safety.
The cupola furnace has been used to melt cast iron for centuries, however, this design is less widespread today. It consists of a vertical steel chamber with a lining of refractory brick. The charge is formed of layers of metal, coke and flux and is introduced through the side of the chamber about half way up. Hot air enters from below. Molten metal forms on a bed of sand at the bottom and is drawn off with a tap.
In many instances cupolas have been replaced by induction furnaces which generate heat through electromagnetic induction. Large copper coils surround the crucible containing the charge. These furnaces are quicker, cleaner and quieter than traditional cupolas and offer precise temperature control. They can be used for melting a wide range of metals and alloys. However, they do not allow for for any refining and some small quantities of melt may be lost to oxidation.
The reverberatory furnace was once widely used for melting brass, bronze and copper. Now largely superseded, these furnaces are still used for melting scrap aluminium for die casting. The key feature of these furnaces is that the charge does not come into direct contact with the fuel and is melted by radiant heat and convection as the combustion gases pass over the hearth to the flue.
In addition to the furnace, a foundry needs other specialised equipment to handle the molten metal and transfer it to the pouring unit. Vessels for transferring molten metal are called ladles and come in a wide variety of shapes and sizes to meet the needs of small workshops and large scale industrial plants. They are commonly made of steel with a suitable refractory lining. The simplest ladles pour from a lip at the top. Others have a teapot shaped spout or pour from the bottom so that impurities floating on the molten metal are separated. All are designed to maximise efficiency and safety.