This article's table of contents introduction:
- Specification Breakdown
- Likely Fan Type: Backward-Curved / Airfoil
- Typical Applications
- Key Features to Look for in such a Fan
- Potential Questions for the Seller / Manufacturer
It appears you are providing a technical specification for a centrifugal fan.
Here is a breakdown of what this specification means, the type of fan it describes, and its typical applications.
Specification Breakdown
- Impeller Diameter: 400 – 3500 mm
- This is a very wide range, covering small industrial fans (400mm / ~16 inches) up to massive heavy-duty fans (3500mm / ~11.5 feet).
- Significance: The larger the impeller, the higher the volume of air (flow) the fan can move.
- High Efficiency:
Refers to the aerodynamic design (often backward-curved or airfoil blades) that converts motor power into airflow with minimal energy loss. This is critical for reducing operating costs (electricity).
- Medium Pressure:
- In fan classification, "Medium Pressure" typically ranges from 1000 Pa to 3000 Pa (≈4 to 12 inches of water gauge).
- Significance: This fan can overcome moderate system resistance (dampers, filters, ducts, heat exchangers) but is not designed for high-pressure applications like pneumatic conveying (which requires high pressure fans) or low-pressure applications like free-air ventilation.
Likely Fan Type: Backward-Curved / Airfoil
Given the emphasis on "High Efficiency" and "Medium Pressure," this specification most likely describes a Backward-Curved Centrifugal Fan (often using an airfoil blade profile).
- Why? Backward-curved fans are the "gold standard" for efficiency in medium-pressure applications. They have a non-overloading power curve, meaning the motor won't burn out if the system pressure drops unexpectedly.
Typical Applications
Because of its size range (400mm to 3500mm) and pressure capabilities, this fan is designed for large-scale industrial, commercial HVAC, and mining/process applications.
Common Uses:
- HVAC Systems: Large air handlers, central station units for commercial buildings (malls, airports).
- Industrial Ventilation: Factories, warehouses, paint booths, fume extraction systems.
- Power Generation: Induced draft (ID) or forced draft (FD) fans in power plants (the 3500mm size is typical here).
- Cement & Mining: Baghouse dust collectors, mine ventilation.
- Tunnel Ventilation: Moving air through road or railway tunnels.
- Process Air: Drying systems, air supply for burners (medium pressure).
Key Features to Look for in such a Fan
If you are sourcing or specifying this fan, you should consider:
| Feature | Importance |
|---|---|
| Blade Profile | Airfoil (highest efficiency) vs. Single Thickness (more robust for dirty air). |
| Housing Material | Carbon steel (standard), Stainless steel (corrosive air), or Wear-resistant steel (abrasive dust). |
| Drive Type | Direct Drive (shaft-mounted motor, no belt loss) vs. Belt Drive (allows speed adjustment/CFM change). |
| Inlet Guide Vanes | Recommended for variable air volume (VAV) systems to save energy. |
| Bearings | Heavy-duty spherical roller bearings with grease purge systems (essential for the large 3500mm impeller). |
| Balance Grade | G 6.3 or higher (ISO 1940) for vibration-free operation. |
Potential Questions for the Seller / Manufacturer
If you are looking to purchase, you should ask:
- What is the exact static pressure range (in Pa or inches wg) for the model? ("Medium" is vague).
- Is this for clean air (airfoil blades) or dirty air (radial/backward inclined blades)?
- What is the maximum operating temperature? (Standard is ~80°C, but high-temp models reach 400°C+).
- Does the efficiency rating meet ISO 12759 or AMCA standards?
- Can the impeller be fitted with a variable frequency drive (VFD)?
In summary: You are describing a large, highly efficient industrial fan designed to move high volumes of air against moderate resistance. It is most likely a backward-curved centrifugal fan used in heavy industry, large HVAC, or power generation. The 3500mm diameter indicates a very large, high-capacity unit (often needing a multi-hundred kW motor).
