How Does a Centrifugal Fan Work?

Centrifugal fans are integral to various industrial processes, but how exactly do they work? This article breaks down the working principles of centrifugal fans, explaining the physics behind their operation and their advantages in industrial settings. We'll also explore CBI's range of industrial centrifugal fans, designed for optimal performance across diverse applications.

Table of Contents:

Introduction to Centrifugal Fans
The Physics Behind Centrifugal Fan Operation
Key Components and Their Functions
Advantages Over Other Fan Types
CBI's Industrial Centrifugal Fan Offerings
Conclusion: The Role of Centrifugal Fans in Industry

An introduction to centrifugal fans

Centrifugal fans move air or gases using centrifugal force. Widely employed in industrial systems, such as manufacturing facilities and process industries, they are valued for their robustness, versatility, and capacity to handle high-demanding workplaces. Their ability to generate significant pressure makes them indispensable in applications where air needs to be moved over long distances or through complex ductwork, unlike axial fans which are generally suited for lower pressure, high-volume airflow.

The physics behind centrifugal fan operation

Centrifugal fans operate by accelerating air radially outward using rotating impellers. As the air enters the fan housing axially, it is thrown outward by the spinning blades due to centrifugal force. This transformation of kinetic energy into pressure results in a steady, high-pressure airflow ideal for demanding industrial applications.

Key physical principles include:

Centrifugal force generated by impeller rotation: This is the primary mechanism by which air gains velocity and is propelled outwards. The faster the impeller spins, the greater the centrifugal force and thus the higher the air velocity.
Energy conversion from mechanical to kinetic to pressure energy: The motor's mechanical energy is converted into the kinetic energy of the moving air, which is then efficiently transformed into static pressure within the fan housing. This pressure is what overcomes resistance in the ducting system.
Static and dynamic pressure regulation through blade shape and housing geometry: The curvature and angle of the blades, as well as the design of the volute (fan housing), are critical in optimizing this energy conversion. Different blade types (forward-curved, backward-inclined, radial) offer varying pressure-volume characteristics and efficiencies.

CBI Group offers tailored centrifugal fans backed by engineering excellence, ensuring reliable performance, safety, and energy efficiency.

Key components and their functions

Understanding the individual components of a centrifugal fan helps in appreciating its overall functionality and maintenance requirements.

Impeller — This is the rotating component that imparts energy to the air. Impellers come in various designs, each suited for specific applications: backward-inclined (BI) and backward-curved (BC) impellers are known for higher efficiency and stable operation, especially in systems with varying resistance. Radial (paddle wheel) impellers are used to move fluids containing filamentous, clogging, and fibrous material, while for dust applications, a simple backward-inclined flat blade is sufficient.
Inlet — This precisely engineered opening allows axial air entry into the fan housing. Its design is crucial for minimizing turbulence and maximizing airflow into the impeller, thereby contributing to overall efficiency.
Fan Housing (Volute) — Also known as the scroll, this casing directs airflow and assists in pressure recovery. As the high-velocity air leaves the impeller, the volute gradually expands, converting the air's kinetic energy into static pressure before it exits the fan. The shape of the volute is optimized to reduce energy losses.
Motor — This powers the impeller, either directly or via transmission. The motor's size and type are selected based on the fan's required speed, power consumption, and operating environment.
Bearings and Shaft — These ensure mechanical stability and smooth rotation of the impeller. High-quality bearings are essential for reducing friction, noise, and vibration, contributing to the fan's longevity and reliable operation.
Mounting Base/Structure — This provides structural support for the entire fan assembly, ensuring stability and proper alignment. Isolation mounts are often used to minimize vibration transmission to the surrounding structure.

Advantages over other fan types

Centrifugal fans offer several technical and functional benefits:

High pressure capability: ideal for systems requiring elevated static pressure
Stable airflow: less susceptible to pulsations compared to axial fans
Robust construction: designed to handle harsh environments (dust, heat, corrosives)
Efficiency in ducted systems: better performance in confined or high-resistance systems
Customisation options: wide adaptability for speed, material, and layout

CBI’s industrial centrifugal fan offerings

CBI Group offers a comprehensive range of centrifugal fans engineered to meet diverse operational demands. Below is an overview of their main product lines.

Ch Series

Airfoil or backwardly inclined flat/curved blade fans for high flow rates (up to 450,000 m³/h) and pressures (up to 6,500 Pa). Suitable for general industrial use.

Discover the Ch Series

ChT Series

Engineered for high efficiency and energy savings, the ChT series features backwardly inclined flat blades with performance up to 750,000 m³/h and 5,000 Pa. This is the DIDW (double inlet double width) version of the Ch series.

Explore the ChT Series

K Series

Features backwardly inclined flat or radial blades. Delivers up to 370,000 m³/h and 9,000 Pa. Excellent for medium-to-high pressure systems.

See the K Series

CB Series

Compact fans with forwardly or backwardly inclined blades. Max flow 20,000 m³/h and pressure 2,000 Pa.

Check out the CB Series

N Series

Compact solution with backwardly inclined curved or radial blades. Max flow 11,000 m³/h and pressure 8,000 Pa.

View the N Series

Z Series

Built with backwardly inclined flat blades, offering up to 400,000 m³/h and 9,500 Pa.

Learn more about the Z Series

EVO Series

Airfoil or backwardly inclined flat blades with direct drive or belt transmission arrangement. Capable of reaching up to 320,000 m³/h and 11,000 Pa. It is also possible to mount axial fans, mainly used to uniform temperature inside industrial ovens.

Discover the EVO Series

S Series

Backwards inclined flat blades with performance up to 200,000 m³/h and pressure of 25,000 Pa. Suited for high-pressure environments, the SMX series is the most robust line designed for very demanding applications.

Explore the S Series

M Series

Engineered with backwardly inclined radial blades. Max pressure 18,000 Pa, 340,000 m³/h. Perfect for installations requiring high resistance.

See the M Series

X Series

Combines high pressure and flow—up to 500,000 m³/h and 10,000 Pa. Designed for versatile industrial applications.

Check out the X Series

H Series

Compact design with backwardly curved or radial blades. Up to 10,000 m³/h and 15,000 Pa.

View the H Series

RT Series

Heavy-duty fan with forwardly inclined radial tip blades. Max flow 700,000 m³/h and pressure 12,000 Pa. All our fans can be designed for high-temperature applications. The RT series is especially used in environments with large amounts of abrasive dust.

Discover the RT Series

Small fan division centrifugal fan

The Small Fan Division (SCF) of CBI Group offers a versatile range of centrifugal fans designed for a multitude of applications. These fans are engineered for simplicity in installation, compactness, efficiency, reliability, and functionality, making them suitable for various industrial environments.

How does a centrifugal fan work?