Industrial Furnaces — History, Working & Components

An industrial furnace is used in many applications, mostly in the metallurgy industry. An industrial furnace is distinguished by the extremely high temperatures, far more than open systems or other heating apparatus. It can be used as a reactor for using the heat produced. An industrial furnace company uses fuel or electricity. The electricity or fuel will heat the furnace by heating the air. The other distinguishing feature of an industrial furnace is its certification. It must meet international standards and codes, specifically ISO 13705.

History of industrial furnaces

The basic idea of a furnace is very old. Human beings have been using fire for heat since the very beginning. Later they learnt to use fire to heat compartments. For instance, the Romans had a system of central heating where they used fire to in the basement to heat air in chimneys, which was then used to heat the floors. Smaller furnaces were used to forge swords and for other metallurgical purposes.

The same principle was later used in industries. It was, in fact, one of the major drivers of the industrial revolution in England. Using coal as a fuel gave furnaces and industrial production the huge boost it needed. In the 70s, electrical furnaces started replacing the fuel furnace. But fuel furnaces are still very popular. Most furnaces are built of stainless steel and aluminium steel.

The corrosion resistance of the stainless steel is ideal for the heat exchangers, while aluminium steel is more suited for blowers, burners and frames. Smaller amounts of brass and copper are also used. Copper is preferred for wiring, while brass is used for fittings, particularly valves.

Working of and industrial furnace

There are different types of furnaces, but the basic design used by most industrial furnace companies of is pretty much the same. It will have a burner where the fuel flows in. Some furnaces can have more than one burner arranged in a cell. These can be mounted on the walls, roofs or the floor. The burners heat tubes that are arranged nearby. The tubes are attached to a fluid-filled section known as the firebox or radiant section. As the tubes heat up, the fluid inside the firebox start to become hot as well.

The temperature of the fluid is tightly controlled and taken to a high level. The gas thus produced is known as flue gas. Most furnaces have a convection section right above the firebox. This section further retains the heat. This heat is then used in the furnace as needed. The residual heat is discharged from the furnace through four gas stack. Heat can be circulated within the furnace as required. The discharge of residual heat is also important to ensure there is no harmful build up.

Also Read: Features of a good preheating oven

Parts of a furnace

The furnace is divided into different parts for the desired build up of heat and for its efficient management. The common components used by industrial furnace company in building their furnace are:

Burner: The burner can be placed on the floor or on walls. It is lit from outside by an ignition starter. This cause the flames to leap out the burner, heating up the air around it.

Radiant section:

This is so named because this is where the radiation from the burner flames heats up the tubes. The placement of the tubes varies from one design to another. The walls of the radiant section have to insulated to prevent heat damage.

Convection section

Placed right above the radiant section, heat is transferred through convection. We can also have a transient zone between the two section, known as bridgezone. The temperature in the bridgezone can be controlled from outside, which also allows us to control the temperature in the convection zone.

Stack

It is a cylindrical structure (most commonly) right above the heating chambers. This is used to collect and throw out the flue gas so as to avoid build up of heat. It has a stack damper that controls the flow of air. This is essential to control the air pressure within. We have to constantly monitor the build up of heat inside the furnace to see that excessive draft is allowed to escape. Build up of hot air is dangerous. At the same time, we need a minimum amount within the furnace for it to work efficiently.

These are the common parts used by industrial furnace companies. The design and working can vary as per type.

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