Industrial exhaust fan are those tools that allow a fluid to move within a network of ducts or within machines or production lines. Just as home fans move the air on hot days, industrial fans move it for various industrial processes.
They are mainly characterized by two quantities:
The world of industrial exhaust fan has evolved and adapted to the production and design needs of the various sectors by offering a wide range of products for different applications.
As you will have understood from my statement, fans are not all the same and above all suppliers are not. Each of them has specialized in making machines suitable for their market and their experience by paying particular attention to some details that others would not even take into consideration.
So, you have to pay close attention both to the choice of the machine but also to find one or more suppliers suitable for your market, your needs and the application.
Having said that, let's say that it is possible to have two large product categories:
From an application point of view, axial fans are mainly common to move huge masses of low head air. We find them mainly in mechanical ventilation units, HVAC, general conditioning or for example in road tunnels.
The centrifugal ones, on the other hand, being able to afford higher performance especially in terms of available head, are common in many industrial applications, both process and auxiliary and we can see them in practically all industrial activities and in all suction, conveyance and emission abatement systems.
The answer is quite simple and mainly concerns the movement that the air makes as it passes through the fan.
In an axial fan, the air substantially does not undergo any "change of direction" between its inlet and its outlet, as you can clearly see:
In a centrifugal fan the air is "centrifuged" towards the outside. It enters the center of the fan and is then pushed towards the passage left open by the blades. In practice, it performs a 90 ° change of direction between its entrance and exit. Look at the three fans below to understand clearly.
Centrifugal plug fans
The fans in the image above are a particular type of industrial exhaust fan which calls plug fan and characterize by the fact that they do not have a casing or scroll around the impeller which is of the centrifugal type.
This particular conformation places them as a "middle way", from a performance point of view of available head, between axial and centrifugal fans.
They are in fact more performing than the axial ones thanks to the centrifugal impeller, but less performing than the purely centrifugal ones due to the lack of the screw which allows to recover every possible Pascal of pressure produced by the impeller.
Precisely because of industrial exhaust fan indispensability in production processes where the movement of air or fluids in general is fundamental. There are different "conformations" for how the fans are built, which call executions.
Everyone knows that a fan is a machine made up of a series of blades that rotate thanks to the thrust of an engine. Industrial fans (as Safe Ventilation explains) work in exactly the same way and mainly concern with passing through the pipes of the industrial ventilation system the polluting gases or dust produced by the various industrial processes.
Industrial exhaust fan generally falls into two main types: axial fans and centrifugal fans. Furthermore, since the world of industry is made up of different sectors, the manufacturers of these machines have specialized by designing a wide range of products suitable for different applications.
Axial fans characterize by propeller fans. This forces the extracted air to move parallel to the shaft around which the blades rotate. It is capable of moving large volumes of air at relatively low pressures. There are three main types of axial fans:
There are substantial differences between axial and centrifugal industrial fans that can summarize schematically. So, let's see how they differ:
There are two fundamental parameters to keep in mind when choosing the most suitable industrial fans:
To identify the appropriate industrial fan, it is necessary to cross the flow-pressure curve of the fan and the flow-pressure curve of the circuit. The point of intersection between the two curves will indicate the fundamental performances that the industrial exhaust fan must have.