Choosing Fan Design Of Id And Fd Fans

By Author: Neel Rao
Total Articles: 131
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Induced draft (ID) and forced draft (FD) fans are crucial pieces of equipment in many industries. These blowers are critical to running factories where there are furnaces and boilers. Choosing the appropriate ID and FD fan design is an important decision for high output and efficiency. The right design of these fans is dependent on many key parameters like the required pressure and airflow requirements of a manufacturing plant.

A plant or a factory has to carefully analyze these aspects. It is only then that a proper decision can be made about the exact blade design for the ID and FD fans. Typically, both the ID and FD blowers make use of centrifugal fan type due to its many advantages. Based on the type of manufacturing plant, there is a variation in the type of impellers used.

Choosing the right FD fan design
These are a few key aspects to be considered while choosing the right FD fan design.

FD fans are with airfoil blades or blades that are backward-curved. This particular design ensures that the air from the external environment is thrust into a furnace or a boiler. The process of combustion gets ...
... completed properly.
These types of blades support medium air pressure.
Backward-curved blades enable operational efficiency.
Airfoil blades are preferred when the sound emitted by the fans has to be on the lower side.
When the supply of air is relatively clean, both the blade types are equally efficient. These blades are extremely useful when the volume of required airflow is high.
Tips for selecting the correct ID fan design
ID fans are primarily used in boilers and industrial furnace systems for creating a negative pressure in the combustion chamber, pulling flue gases out of the system, and discharging them to the chimney. They are located at the outlet of the combustion system or heat exchanger. The negative pressure helps in efficient combustion by ensuring the air/fuel mixture is drawn in and exhaust gases are removed.

These are a few key aspects to be considered while choosing the correct induced draft fan design.

Here, choosing either the backward-curved or the radial versions is the best option.
It is blowers with these designs that can efficiently gather flue gases present within the system, and promptly eliminate them into the outside atmosphere.
To achieve the above objective, it’s imperative that the fans create high levels of air pressure. Both the radial and backward-curved designs help in generating this air pressure.
Blowers with these blade designs will be able to handle hot, corrosive gases found inside combustion chambers or furnaces.
Normally, plants choose a radial design when they want the blades to be highly robust. This robustness is essential to withstand hot, dusty, and corrosion-causing gases. The radial blades withstand such harsh conditions.
Similarly, if the gases are relatively clean, then plants optimize for blades of the highest efficiency – in such situations the backward-curved variants are chosen.
Furnaces and combustion chambers are not the only systems where these fans are used. Radial and backward-curved ID fans find their usage in kilns, dust collectors, and incinerators, too.
Sometimes, we see that these blades have special coatings or wear liners. Obviously, these models are more rugged than the regular versions. They are useful in plants or factories where the systems are required to handle extremely corrosive and dusty gases.
In this article, we have summarized the logic that goes into the choosing of a suitable fan design for both ID and FD fans for a variety of manufacturing processes.

Reitz India ID Fan are custom designed to serve the needs of various processes in industries like cement, iron & steel, power plants, fertilizers/ chemicals and more. As a top quality Induced draft fan, has set a benchmark in delivering superior fans with high quality features and better industrial standards.