Furnaces are used in a huge range of industries. They are essentially ovens – heating a space or material. Not all furnaces are the same, however. Traditionally, blast furnaces were the most popular kind. These machines used combustion to heat a chamber. Today, induction heating has become the new normal.
Here is a look at 5 of the most important kinds of furnace used in industry today.
1. Ashing Furnace
Ashing furnaces are used to completely combust the objects placed within – leaving behind an ash. This is done for many reasons. In the food science industry, ashing is used as a part of the process for finding out the composition of a food so that it can be displayed on packaging. In the waste disposal industry these furnaces are used to get rid of sensitive medical waste. The furnaces typically used to cremate people and animals are also technically ashing furnaces.
2. Rotary Tube Furnace
Rotary tube furnaces are used in physiochemical processing. These specialist furnaces allow samples to be mixed and heated simultaneously. In pharmaceuticals and laboratory testing these devices are invaluable tools. In order to both mix and heat at the same time, the samples are housed in a cylinder which, as the name suggests, rotates.
3. Induction Melting Furnace
In the metallurgic refinement and recycling industry the induction melting furnace is an essential tool of the trade. Induction furnaces are clean, efficient and easy to control. Induction furnaces work by provoking eddy currents in a nonconductive crucible. This crucible is surrounded by copper wire, through which is passed an alternating electrical current. This induces eddy currents in the crucible using magnetic induction and heats it up to incredible temperatures. Most modern foundries use this kind of furnace because it does not involve any kind of combustion whatsoever and can be controlled using remote electrical panels.
4. Sintering Furnace
Sintering – also known as frittage – is a process that involves the heating of powder compounds in order to increase the eventual strength of a metal product. Frittage needs to take place in a special oven that is held at a temperature just below the melting point of the material that is going to be sintered. Some sintering ovens allow for the insertion of tools for the manipulation of objects while they are inside. Sintering is more effective when conducted in a vacuum, which has led many manufacturers to produce vacuum sintering furnaces.
5. Annealing Furnace
Annealing is a process in which metals are heated up in order to improve their ductility. Increased ductility means increased malleability, which tends to lead to metal being easier to work with. In order to be effective, annealing furnaces need to be able to keep metals at a consistent high temperature and be controlled very accurately. Any inaccuracy can lead to metals melting and becoming unworkable. Annealing furnaces typically use electrical induction in order to transfer heat as this method allows for a very stable and consistent temperature if a constant supply of power is provided.