FBCDZ-6-No31 Coal Mine Exhaust Explosion-Proof Counter-Rotating Axial Flow Fan

This article's table of contents introduction:

1. Model Breakdown (Nomenclature)
2. Full Name
3. Key Design Features
4. Technical Specifications (Approximate for No31)
5. Application
6. Operation and Efficiency
7. Common Manufacturers
8. Safety and Maintenance
9. In Summary

Based on the product model you provided, FBCDZ-6-No31, here is a detailed breakdown of what this equipment is, its specifications, and its application.

This is a specific model of a large, explosion-proof ventilation fan used primarily in underground coal mines.

Model Breakdown (Nomenclature)

The model FBCDZ-6-No31 follows Chinese industry standards for mine ventilation fans:

• F : Fan
• B : Explosion-proof (防爆)
• C : Counter-rotating (对旋)
• D : Motor direct-drive (电机直联)
• Z : Main ventilator for mine (主扇)
• -6 : Pole Number (Motor). This indicates the motor has 6 poles. For a 50Hz power supply (standard in China), a 6-pole motor runs at a synchronous speed of ~980 RPM (revolutions per minute).
• -No31 : Impeller Diameter. "No" stands for "Number", where the number indicates the impeller diameter in decimeters (dm). Therefore, No31 = 31 dm = 3100 mm (or approximately 2 feet).

Full Name

FBCDZ-6-No31 Coal Mine Exhaust Explosion-Proof Counter-Rotating Axial Flow Fan

Key Design Features

1. Counter-Rotating (C): The fan has two impellers mounted on the same axis but rotating in opposite directions.
   • The first-stage impeller acts as a rotor.
   • The second-stage impeller acts as a stator/rotor, recovering the rotational energy from the first stage.
   • This design eliminates the need for heavy, expensive stator vanes, making the fan more compact and efficient.
2. Explosion-Proof (B): All electrical components (motors, junction boxes) are housed in explosion-proof enclosures. This is mandatory for coal mines where methane gas can be present.
3. Direct Drive (D): Each impeller is directly mounted on the shaft of its own explosion-proof motor. There are no belts, pulleys, or couplings inside the fan housing, which increases reliability and safety.
4. Exhaust: This fan is specifically designed for the exhaust (return air) side of the mine ventilation system. It pulls air out of the mine, creating negative pressure.

Technical Specifications (Approximate for No31)

Note: Exact performance depends on the specific manufacturer's design ( blade angle, motor power, etc.). The following are typical ranges for a fan of this size.

• Impeller Diameter: 3100 mm (3.1 meters)
• Motor Power (per impeller): Typically two motors of 200 kW to 500 kW each (total power of 400 kW to 1000 kW).
• Voltage: Usually 380V, 660V, 1140V, or 6kV / 10kV (High voltage is common for motors this large).
• Air Volume (Flow Rate): Typically 10,000 m³/min to 30,000 m³/min (600,000 m³/h to 1,800,000 m³/h).
• Fan Static Pressure: Typically 1,000 Pa to 5,000 Pa (depending on mine resistance).
• Speed (Synchronous): 980 RPM (on 50Hz). The actual operating speed may vary slightly.
• Noise Level: High (requires silencers for operation near inhabited areas).

Application

• Primary Mine Ventilation: This is a major piece of equipment used as the main exhaust fan at the mine's air return shaft.
• Large-Scale Mines: The No31 size is for large to super-large coal mines with significant ventilation demands.
• Gassy Mines: Specifically for mines with high methane emission levels where explosion-proof equipment is legally required.

Operation and Efficiency

• High Efficiency: Counter-rotating fans are known for high static efficiency (often reaching 80% or more at their best efficiency point).
• Adjustable Performance: Performance is typically adjusted by:
  1. Blade Angle: Manually adjusting the angle of the impeller blades (pitch). This is the most common method for changing the duty point.
  2. Speed Control: Using high-voltage variable frequency drives (VFDs) to control motor speed. This is becoming more common for energy savings but requires a significant investment.

Common Manufacturers

In China, major manufacturers of these fans include:

• Shandong Fuhua (often associated with the FBCDZ series)
• Shijiazhuang Anlong
• Heilongjiang Jiarui
• Wenzhou Hengtong

Safety and Maintenance

• Maintenance: Requires scheduled shutdowns for bearing inspection, blade tip clearance checks, and motor insulation testing. The direct-drive design means scheduled motor maintenance is critical. Lifting and handling the large motors (which can weigh several tons each) requires specialized equipment.
• Anti-Surge: A fan of this size is capable of producing high pressure. It must be operated with an open inlet or outlet (typically with a guillotine door or louvered damper) to avoid operating in the stall/surge region, which can destroy the fan.

In Summary

The FBCDZ-6-No31 is a heavy-duty, explosion-proof, direct-drive, counter-rotating axial fan with a 3.1-meter impeller diameter. It is designed for the main exhaust ventilation of large coal mines. It has high efficiency due to its counter-rotating design and is strictly built to safety standards for use in explosive atmospheres.