4-68-14D Centrifugal Fan

This article's table of contents introduction:

1. Decoding the Model Number: 4-68-14D
2. Key Specifications & Dimensions (Approximate)
3. Common Motor Power & Speed
4. Potential Issues & Considerations
5. Where is this fan used?

Based on the part number 4-68-14D, you are likely referring to a specific model of a centrifugal fan, also sometimes called a backward-inclined or airfoil centrifugal fan. This number does not follow a universal standard from a single manufacturer (like Greenheck, ebm-papst, or New York Blower) but instead follows a common Chinese naming convention used by many manufacturers for industrial fans.

Here is the breakdown of what these numbers typically mean and the specifications of the fan.

Decoding the Model Number: 4-68-14D

This model number usually represents a fan used for high-efficiency, medium-pressure ventilation systems (like HVAC, dust collection, or general industrial air movement).

• "4" : This likely indicates a series or design code. It often denotes a backward-inclined (or airfoil) blade design, which is known for high efficiency and non-overloading power characteristics.
• "68" : This is the specific type or performance designation. It is a very common code for general-purpose, high-efficiency centrifugal fans. The "68" series is known for having backward-curved blades.
• "14" : This is the impeller (fan wheel) diameter in decimeters (dm). 14 dm = 4 meters (4 ft 7 inches) .
  • Why this matters: This is a large fan. It moves a very high volume of air (Cubic Feet per Minute / Cubic Meters per Hour).
• "D" : This indicates the drive arrangement.
  • D typically stands for Direct Drive or Overhung Pulley Drive but in the context of industrial fans in this series, "D" usually means the impeller is overhung and directly coupled to the motor (or driven via a shaft and bearings) rather than being mounted on the motor shaft directly. Specifically for Chinese standard fans: D = Impeller overhung, supported by two bearings, driven by a coupling. (Other common suffixes: A = Direct Drive motor mounted, C = Belt Drive).

Key Specifications & Dimensions (Approximate)

• Fan Type: Centrifugal, Backward-Inclined (Backward Curved)
• Impeller Diameter: 1,400 mm (55 inches)
• Applications: Large HVAC systems, factory ventilation, fume extraction, forced draft in boilers, grain drying.
• Expected Airflow (High Volume): Depending on the specific wheel width and RPM, this fan can move between 50,000 to 150,000 m³/h (29,000 to 88,000 CFM) .
• Expected Pressure: Medium pressure, typically 2,000 to 4,000 Pa (8 to 16 inches w.g.) .
• Rotation: Typically "Right" (clockwise) or "Left" (counter-clockwise) from the drive side.
• Discharge Position: Usually available in 0° (downblast), 45°, 90°, 135°, 180°, 225°, 270°, 315°.

Common Motor Power & Speed

For a 1.4m impeller in this series:

• RPM (Speed): Typically around 730 RPM (for 50Hz) or 880 RPM (for 60Hz) at lower pressures.
• Power: A 4-68-14D fan usually requires a motor in the range of 37 kW to 90 kW (50 HP to 120 HP) depending on the air density and static pressure requirements.

Potential Issues & Considerations

When dealing with a 4-68-14D Fan:

1. Noise: This is a large, high-speed fan. It will generate significant noise (likely >85 dB(A)) and likely requires a silencer (sound attenuator) in the ductwork.
2. Vibration: Direct drive (or large coupling drive) requires a very rigid baseplate and precise alignment. Imbalance in a 1.4m wheel can be catastrophic.
3. Inlet / Outlet Conditions: This type of fan is very sensitive to poor inlet conditions (turbulence). It needs a straight duct at the inlet (minimum 1.5x impeller diameter) to perform at its rated efficiency.
4. Static Pressure: Do not run it at too low a static pressure (close to free air) as backward-curved fans can draw very high power at low resistance, potentially overloading the motor.

Where is this fan used?

Due to its size and medium-pressure, high-volume nature, you find the 4-68-14D in:

• Cement Plants
• Power Plants (Forced Draft / Induced Draft)
• Steel Mills
• Large Central HVAC Systems (Return/Exhaust Plenums)
• Mine Ventilation

Need more specific info?

To give you exact specifications (RPM, kW, CFM, Weight), I would need to know:

1. Who is the manufacturer? (e.g., "Yilida," "Syntron," or a generic Chinese brand)
2. Are you looking for a specific static pressure? (e.g., "at 3000 Pa")
3. What is the wheel width? (Often noted as "No. 14D" but the wheel width can vary, e.g., 14D F, 14D B).

Warning: If this is a replacement, the dimensions (bolting holes, shaft height, base flange) are not standardized across all makers. Always get a general arrangement drawing before ordering. Do not assume a "4-68-14D" from one Chinese factory will bolt directly to the duct of another without careful measurement.