This article's table of contents introduction:
- What does this combination mean?
- The Common Fan Type: Backward Inclined / Airfoil (BI/AF)
- Typical Configurations (Class I, II, III, IV)
- Key Components & Specifications
- Common Applications
- How to Find / Specify One (Example Code)
- Major Manufacturers (Including Double Suction High Pressure Lines)
- Summary Table
It sounds like you're looking for a High Pressure Centrifugal Fan that features a Double Suction (Double Inlet) design and delivers High Airflow.
This combination is a very specific, heavy-duty industrial fan. Here is a breakdown of what that means, the typical applications, and the key types of fans that fit this description.
What does this combination mean?
- Double Suction (Double Inlet): The fan wheel is open on both sides. Air is drawn into the impeller from two opposite directions simultaneously.
- Advantage: This design balances the axial thrust on the motor bearings, making it smoother and more stable. It also allows for a wider impeller (for more airflow) while maintaining a relatively compact housing width.
- High Pressure: The fan is designed to overcome significant system resistance (static pressure) from ductwork, filters, dust collectors, or long material handling runs.
- High Airflow: The double-inlet design naturally allows for a much larger volume of air to be moved compared to a single-inlet fan of a similar diameter.
The Common Fan Type: Backward Inclined / Airfoil (BI/AF)
The most common and efficient fan type for High Pressure + Double Suction + High Airflow is the Backward Inclined (BI) or Airfoil (AF) Double Inlet (DWDI) fan.
- Why?
- Efficiency: These are the most efficient centrifugal fan designs (up to 85-90%).
- Stability: They have a stable, non-overloading power curve. They can handle pressure drops without burning out the motor.
- Quiet Operation: They are generally quieter than radial-blade fans.
- High Pressure Capability: They can generate high static pressures (typically up to 20-40 inches w.g. or more in larger sizes).
Typical Configurations (Class I, II, III, IV)
High pressure fans are categorized by their structural strength (wheel and housing thickness) to withstand the centrifugal forces. A high pressure, high airflow double suction fan is almost always Class III or Class IV or HVAC Heavy Duty.
- Class I: Light duty, low pressure.
- Class II: Moderate duty.
- Class III: High pressure, heavier construction. This is likely what you need.
- Class IV: Very high pressure, most robust construction.
Key Components & Specifications
When specifying this fan, look for these features:
| Component | Specification for High Pressure Double Suction |
|---|---|
| Wheel Type | Backward Inclined (BI) or Airfoil (AF) |
| Inlet | Dual inlet with conical or flanged inlets |
| Housing | Welded steel, split housing (for maintenance) |
| Bearings | Heavy-duty, spherical roller bearings with grease fittings |
| Shaft | Oversized, turned and polished steel |
| Drive | Belt drive (for variable speed via sheave changes) or Direct Drive (for constant speed) |
| Materials | Steel (standard), Corten/A588 (for corrosion), Aluminum (for spark resistance), Stainless Steel (for corrosive gases) |
Common Applications
- Large HVAC Systems: For large commercial buildings, stadiums, airports, data centers.
- Dust Collection & Material Handling: Moving large volumes of air with dust (e.g., woodworking, cement, grain).
- Industrial Process Air: For drying, combustion air, or exhaust in heavy industries.
- Fume Exhaust: For large chemical or laboratory exhaust systems.
- Car/Truck Painting Booths: Moving huge volumes of heated filtered air.
How to Find / Specify One (Example Code)
You might see a fan specified as: DWDI (Double Width Double Inlet) Class IV, 200,000 CFM at 24" SP, 150 HP Motor.
To find a manufacturer or supplier, search for these terms:
- "DWDI Backward Inclined Fan"
- "Double Suction High Pressure Blower"
- "Industrial Class IV Fan"
- "Heavy Duty Airfoil Fan"
- "Arrangement 3 Double Inlet Fan" (Arrangement 3 means the wheel is mounted on a shaft between two bearings)
Major Manufacturers (Including Double Suction High Pressure Lines)
- Greenheck: (Fans like the GBSW or GBSW-C - Belt Drive, High Pressure)
- New York Blower: (The classic Pressure Blower line or LSB series)
- Twin City Fan: (The PE, BIA, or BC series)
- Howden: (Heavy industrial, e.g., Buffalo Forge)
- Robinson Fans: (Specialized for high pressure and high temperature)
- Chicago Blower: (The B or P series)
Summary Table
| Feature | Typical Double Suction High Pressure Fan |
|---|---|
| Airflow | Very High (50,000 CFM to 500,000+ CFM) |
| Pressure | Medium to Very High (12" to 40"+ W.G.) |
| Efficiency | High (80-90%) |
| Wheel Type | Backward Inclined or Airfoil |
| Primary Use | Large industrial process, HVAC, dust collection |
Final Recommendation: If you need a fan that combines high pressure with very high airflow and has two inlets for balance and capacity, you are almost certainly looking for a Backward Inclined (or Airfoil) Double Width Double Inlet (DWDI) Class III or IV fan.
Would you like help determining the correct CFM (airflow) and static pressure (SP) required for your specific system so we can better narrow down the model?
