Air suspension centrifugal fans, also known as single-stage high-speed centrifugal fans, are a new type of fan known for their high efficiency, low noise, and low energy consumption. Below, we will detail their structure and operating principles:
Structure Composition Air Suspension Bearing System: One of the core technologies of this fan is the air suspension bearing. The air suspension bearing adopts a design without contact or friction, suspending the shaft in the air through the air film generated by high-speed rotation. This avoids the wear and maintenance issues of traditional mechanical bearings, thereby improving the fan’s lifespan and reliability.
High-Speed Motor: The fan is equipped with a high-speed permanent magnet synchronous motor (PMSM), known for its high efficiency and power density. The motor is directly connected to the impeller, eliminating the need for a reducer or gear transmission, thereby reducing energy loss and mechanical wear.
Impeller: The impeller is made of high-strength lightweight materials (such as aluminum alloy or titanium alloy), undergoes precise processing and dynamic balance treatment to ensure its stability and efficiency during high-speed rotation. The single-stage design simplifies the structure and improves efficiency.
Control System: The fan is equipped with an advanced control system, including a frequency converter and PLC control unit. The frequency converter adjusts the motor’s speed according to actual needs to achieve precise control of air volume and pressure. The PLC control unit is responsible for system operation monitoring, fault diagnosis, and protection functions.
Cooling System: Due to the high-speed operation generating a large amount of heat, the fan is usually equipped with an effective cooling system, such as air cooling or water cooling, to ensure the safe operation of the motor and other key components.
Operating Principle Air Suspension: When starting, the control system first supplies air to the air suspension bearing, creating a certain air pressure inside the bearing to suspend the rotor in the air. As the motor accelerates, the rotor reaches the working speed, the air film of the bearing stabilizes, and the rotor is completely suspended without contacting the bearing surface.
Air Compression: The high-speed motor drives the impeller to rotate, and air is sucked in through the intake and enters the impeller. Under the action of the high-speed rotation of the impeller, the air is compressed, increasing kinetic energy and pressure.
Air Exhaust: The compressed air passes through the diffuser (or expansion device) to further convert kinetic energy into pressure energy, thereby achieving efficient air exhaust. The discharged air enters the usage system or pipeline through the exhaust port.
Control and Regulation: The fan’s control system monitors air volume, pressure, temperature, and other parameters in real-time through sensors, automatically adjusts motor speed and fan operating status to adapt to different working conditions and requirements. The frequency converter allows for stepless speed regulation as needed, achieving energy-saving and efficient operation.
Application Fields: Air suspension centrifugal fans are widely used in sewage treatment, pneumatic conveying, food processing, electronics manufacturing, chemical industry, and other fields, especially suitable for industrial environments requiring high efficiency, stability, and low noise.
In the efficient and reliable operation of air suspension centrifugal fans, metal expansion bellows manufactured by Shanghai Songjiang Group play a crucial role. Their primary functions include vibration reduction and noise control, protection of the fan and associated piping systems, and absorption and filtration of vibrations generated by the fan. Here’s an in-depth look at how these expansion bellows contribute to the performance and longevity of air suspension centrifugal fans:
- Vibration and Noise Reduction Despite their advanced design, air suspension centrifugal fans still generate vibrations during operation due to the high-speed rotation of the impeller and airflow dynamics. These vibrations can propagate through the system, causing noise and potential disruptions.
Metal expansion bellows are designed to effectively absorb and dampen these vibrations. Made from flexible materials and engineered to withstand dynamic movements, these bellows act as a buffer between the fan and the connected ductwork or piping. By absorbing the vibrations, they significantly reduce the transmission of noise and vibration through the system, creating a quieter and more stable operating environment. This is particularly important in settings where noise control is critical, such as in residential areas or noise-sensitive industrial applications.
- Protection of Fan and Piping System The robust operation of air suspension centrifugal fans involves considerable mechanical stress, which can adversely affect both the fan and the connected piping over time. Without adequate protection, the vibrations and thermal expansions can lead to mechanical fatigue, cracks, or even catastrophic failure of these components.
Metal expansion bellows provide a flexible connection that accommodates these movements and stresses. They allow for thermal expansion and contraction, as well as lateral, axial, and angular movements without transmitting excessive forces to the fan or piping. This flexibility protects the integrity of the entire system, ensuring a longer service life for both the fan and the piping. By preventing undue stress and strain, these bellows minimize the risk of mechanical failure and the associated downtime and maintenance costs.
- Absorption and Filtration of Vibrations The high-speed operation of air suspension centrifugal fans inherently produces a range of vibrations, from low-frequency oscillations to high-frequency vibrations. If not managed properly, these vibrations can lead to operational inefficiencies and mechanical wear.
Metal expansion bellows are specifically designed to absorb and filter these vibrations. Their construction typically includes multiple layers of elastomeric materials, which are highly effective at damping a wide range of vibrational frequencies. By filtering out these vibrations, the bellows help maintain the precise alignment and operational stability of the fan. This not only enhances the efficiency of the fan but also reduces the wear and tear on its components, leading to more consistent performance and reduced maintenance requirements.
