fan impeller

The impeller is the heart of a fan. The motor drives the impeller to rotate, converting mechanical energy into pressure energy and kinetic energy of gas, directly determining the fan's air volume, air pressure, efficiency, noise, and operational stability.

1、 Basic structure (centrifugal impeller)

Wheel hub (shaft disc): connects the main shaft and transmits torque

Rear disk (disc): the substrate that carries the blades

Blade: Doing work on gas, blade profile is key to performance

Front plate (wheel cover): Seal the blade flow channel to reduce gas backflow and leakage

Simplified Axial Flow Impeller Structure: Hub+Several Blades, Some Blades Angle Adjustable

2、 Three types of blades for centrifugal impellers

1. Backward bending (backward) impeller | The bending direction of industrial mainstream blades is opposite to the rotation direction; Wing shaped/flat plate rear bend.

Advantages: high aerodynamic efficiency, stable operation, low vibration, and low noise;

Disadvantages: Low wind pressure at the same rotational speed;   👉 Applicable: dust removal, exhaust gas transportation, large induced draft fans, long-term continuous operation conditions.

2. Forward bending (forward/multi wing) impeller blades have a bending direction and rotation direction, and a large number of blades.

Advantages: High wind pressure and compact size for the same size;

Disadvantages: Low efficiency, easy to accumulate dust;   👉 Applicable: air conditioning units, ventilation purification, small equipment internal circulation fans.

3. Radial impeller (straight blade) blades extend outward along a radial straight line.

Advantages: Simple structure, wear-resistant, and not easily clogged with dust;

Disadvantages: Poor efficiency, excessive noise;   👉 Applicable: high dust, particulate media, coal powder, sand and gravel flue gas.

Open and close according to structure: closed (with complete front and rear panels, highest efficiency, clean gas), semi open (with only the rear panel and a small amount of dust), open (without front and rear panels, high dust/fiber media)

3、 Axial flow impeller

Similar to a propeller, the airflow enters and exits along the axis of rotation, and the blade angle can be adjusted to change the air volume and pressure on site. Large air volume and small volume; Low wind pressure; Applicable: Factory ventilation, cooling tower, fire smoke exhaust, pipeline direct discharge.

4、 Common materials

Q235/Q345 carbon steel: universal room temperature air, low cost; Dust working conditions can be treated with tungsten carbide wear-resistant spraying

304/316L stainless steel: damp, acid alkali corrosion, high temperature waste gas from food and pharmaceutical industries

Aluminum alloy: Lightweight small fan, clean air, not resistant to wear and high temperature

Fiberglass FRP: Strong acid and alkali waste gas, temperature generally ≤ 120 ℃

Titanium alloy: Strong corrosion in high-end working conditions, high cost

5、 Key processes and acceptance points

Cutting: Laser cutting to ensure blade consistency

Welding: Full welding+stress relief to prevent deformation and cracking during high-speed rotation

Dynamic balancing: It must be done before leaving the factory (commonly G4.0 grade). Unbalance can cause severe vibration, bearing damage, and complete machine scrapping

Anti corrosion and wear-resistant: spray painting, galvanizing, wear-resistant coating

6、 Common faults

Ash accumulation: blade scaling, disruption of dynamic balance, and soaring vibration

Wear and tear: Dust erosion, thinning of blades, severe wear and tear

Corrosion: Corrosion caused by acidic water vapor, resulting in pitting and cracking

Fatigue cracking: Long term alternating stress, weld or blade root fracture