Core principle and structure of multi-stage centrifugal blower

Core working principle: Gradual conversion of kinetic energy to potential energy

The multi-stage centrifugal blower achieves continuous gas pressurization through the series connection of multi-stage impellers, which essentially involves the efficient conversion of kinetic energy into pressure energy (potential energy). After being sucked in from the axial direction, the gas first enters the first stage impeller and is accelerated to radial high-speed flow under the centrifugal force of high-speed rotation (usually 3000-15000 rpm), at which point the kinetic energy of the gas is significantly increased. Subsequently, the high-speed airflow enters the diffuser - its cross-sectional area gradually increases, forcing the airflow to slow down. According to Bernoulli's principle, kinetic energy is converted into static pressure energy, and the pressure further increases. After completing the first stage of compression, the gas is guided by a reflux device (guide vane) to change its flow direction and evenly introduce it into the inlet of the next stage impeller, repeating the above acceleration expansion process. For each additional level, the pressure is gradually added and finally collected by the snail shell to output high-pressure gas.

Key mechanism:

The pressure increase mainly occurs in the impeller (about 60-70%) and the diffuser (about 30-40%)

The single-stage pressure ratio is usually 1.15-1.3, and the multi-stage total pressure ratio can reach 1.5-3.0

Compared to single-stage fans, multi-stage structures can achieve the same pressure at lower speeds, avoiding material and dynamic balance limits and improving reliability

Core Structure Composition: Precision Engineering Integration

The multi-stage centrifugal blower consists of four major systems, and each component works together to achieve efficient, stable, and oil-free operation:

|System | Core Components | Materials and Design Features | Functional Description|

|Rotor system | Impeller, main shaft, balance disc | Impeller: aluminum alloy (below D400) or high-strength alloy steel (above D400). Main shaft: high-quality carbon steel or alloy steel, quenched and tempered. | Impeller adopts wing shaped or ternary flow meridian aerodynamic design, improving efficiency to over 78%; The main shaft is designed as a rigid shaft with support at both ends. After static/dynamic balance correction, the vibration is ≤ 2.8mm/s|

|Chassis system | Chassis, diffuser, reflux device, volute shell | Grey cast iron (HT250 or above), horizontally split or integral series structure | Multiple stage diffusers and reflux devices are installed inside the chassis to form a closed airflow channel; The snail shell is spiral shaped, efficiently collecting gas and reducing outlet turbulence|

|Sealing system | Inter stage sealing, shaft end sealing | Maze seal (zipper/comb structure), made of stainless steel sheet or alloy aluminum | Non contact design, no wear, no heat, leakage rate<0.1%, suitable for conveying clean gases (such as sewage treatment aeration)|

|Bearings and transmission systems | Rolling bearings/sliding bearings, couplings | Double support structure, lubrication method is lithium grease or pressure oil supply; Direct transmission is the main method, supplemented by belt transmission. Bearings bear radial and axial loads to ensure high-speed rotational stability; The coupling transmits torque and also has overload protection function|

Frontier Technology Evolution: Magnetic Suspension and Intelligent Control

The current high-end products have been upgraded towards contactless, high-efficiency, and intelligent directions:

Magnetic levitation centrifugal blower: using active magnetic levitation bearings (AMB) and permanent magnet synchronous direct drive motor, completely eliminating mechanical friction and gearbox, with a speed of up to 36000 rpm, a comprehensive energy-saving rate of 30-40%, noise ≤ 75dB (A), achieving "zero oil, zero maintenance"

Intelligent monitoring system: integrates vibration, temperature, and pressure sensors, supports remote operation and maintenance, and fault warning, in line with the trend of Industry 4.0

Variable frequency control: By adjusting the motor frequency to achieve stepless flow regulation, matching process requirements, and avoiding throttling losses

Chinese standards and industry norms

According to GB/T 28381-2012 "Energy Efficiency Limits and Energy Efficiency Evaluation Values for Centrifugal Blowers", multi-stage centrifugal blowers are divided into:

Multi stage low-speed centrifugal blower (≤ 3000 rpm)

Multi stage high-speed centrifugal blower (>3000 rpm)

Shandong Ruidian Environmental Protection Technology Co., Ltd. is located in the high-end equipment manufacturing base of Luozhuang District, Linyi City. It is a modern enterprise that focuses on the research and development, design, production, and manufacturing of multi-stage centrifugal blowers, centrifugal vacuum pumps, Roots blowers, pneumatic conveying systems, and soil remediation integrated special equipment. Its telephone number is 13287120066.