The Most Common Types Of Industrial Fans

Fan systems provide customized solutions in industrial applications for various purposes from cooling and exhausting heat to dust collection and material handling. The amount of air flow required, pressure and efficiency will decide which type of fan has to be used in the industrial process. Generally, in industries two primary types of fans are used - centrifugal fan and axial fan. These fans differ from each other in design, functionality and air flow direction.

Axial Fans -

• In axial fan, the flow of air is in a linear direction, which means the fan forces air across its axis parallel to the direction of rotation along the shaft. In this design, there will be no change in the direction of the air flow.
• The fan arrangement consists of a propeller, rotating in a round section of the duct, which is mounted to a wall or duct to exhaust air from a system or process. Axial fans are also equipped with guided vanes to eliminate air twist at the inlet or outlet and direct airflow through the blades in a linear direction.
• The dimensions and size of the axial fan used, vary depending on the operating conditions and the installation location. Axial fans are available with various blade shapes such as aerofoil, paddle, variable pitch etc. Among them, aerofoil blade shapes are considered for effective standard fan design because of their higher efficiency and low noise levels.
• The most common types of industrial axial fans are – tube axial, propeller & vane axial. Depending on the air flow requirements, axial fans can be custom designed for single stage impeller or multi-stage versions. Axial fans are efficient, require low power inputs, and can operate at high static pressures if necessary.

Applications:

• Axial flow fans are capable of handling industrial processes that require large volumes of air at relatively low pressures.
• Axial fans such as tube axial and vane axial are used in industrial applications where a uniform downstream of air distribution is required. These fans are used in cement, paper & wood, pharmaceutical, steel industry etc for handling critical processes that require drying, ventilation, fume & hot air exhaust etc.

Centrifugal Fans

• In centrifugal fans, the speed of air stream entering into the fan, is increased by the impeller. Initially the air stream enters fan impeller in an axial direction, but changes its direction by 90° due to centrifugal force and gets discharged in radial direction.
• Centrifugal fans have three drive shaft mechanisms - direct, belt driven and variable.
• Centrifugal fans have varied blade configuration such as forward curved, radial, backward curved, airfoil etc., based on which they are categorized into various fan types. Depending on the volume flow rate and pressure requirements, fan types with different designs and capabilities are being used for various processes of industrial applications.
• To achieve desired change in airflow, these fans are equipped with dampers, louvers and guided vanes. Sometimes, the desired airflow rate can be achieved by combining multiple fan systems in series or parallel arrangement.

Applications:

• Centrifugal fans are suitable for use with systems having high static resistance. These fans are widely used in several process plants such as cement, steel, chemical, thermal power etc where air movement is necessary.
• Centrifugal fans and blowers provide customized solutions to many industries for dust collection, material handling, boiler applications, ventilation, drying & cooling, pollution control, air recirculation etc. The fan design can be tailor-made to withstand different operating conditions such as low or high temperatures, abrasive dusty materials, acidic fumes, corrosive gases etc.

The type of the fan installed is specific to industrial process.

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