This article's table of contents introduction:
- Model Name Breakdown
- Key Technical Features
- Typical Performance Parameters (FBCDZ-6-No21)
- Common Applications
- Advantages & Disadvantages
- Typical Equivalents
- Installation & Operation Notes
The designation FBCDZ-6-No21 refers to a specific model of a coal mine main ventilation fan, classified as an explosion-proof, counter-rotating axial flow fan.
Here is a detailed breakdown of what the model name means, its key features, and its typical specifications.
Model Name Breakdown
The model name "FBCDZ-6-No21" follows the Chinese national standard for mine ventilation fans:
- F – Fan (通风机)
- B – Explosion-proof (防爆) - The motor and electrical components are designed to prevent ignition of flammable mine gases (like methane).
- C – Counter-rotating (对旋) - The fan has two impellers that rotate in opposite directions. This eliminates the need for stator vanes and improves efficiency.
- DZ – Main fan for mine (煤矿主通风机) - Specifically designed for primary mine ventilation.
- 6 – Impeller blade number (叶片数) - This typically means each impeller has 6 blades.
- No21 – Impeller diameter (机号) - The diameter of the impeller is 21 decimeters, which is 1 meters.
Key Technical Features
- Counter-Rotating Design: The two impellers are mounted on two separate motors. The front impeller rotates clockwise, and the rear impeller rotates counter-clockwise. This design provides high pressure and high airflow without the need for complex guide vanes.
- Explosion-Proof: The motors and all electrical components are explosion-proof (ExdI or ExdIIBT4 certified), making it safe for use in underground coal mines where methane gas is present.
- High Efficiency: Counter-rotating fans offer a steep pressure curve and high dynamic efficiency (often up to 85% or more).
- Direct Drive: In most models, the impellers are directly mounted on the motor shafts, eliminating the need for belts or couplings, which reduces maintenance.
- Reversible Airflow: The fan can reverse the airflow direction (for emergency evacuation or ventilation reversal) by reversing the rotation of the motors. Counter-rotating fans typically maintain 60-70% of forward efficiency when reversed.
Typical Performance Parameters (FBCDZ-6-No21)
Note: These are approximate values. Specific performance depends on blade angle, speed, and manufacturer.
| Parameter | Typical Value |
|---|---|
| Rated Diameter | 2100 mm (2.1 m) |
| Motor Type | Explosion-proof three-phase asynchronous motor (YBFe or similar) |
| Motor Power | Typically 2 × 160 kW to 2 × 250 kW (Two motors) |
| Voltage | 380V / 660V / 1140V (depending on mine voltage) |
| Rated Speed | 980 rpm or 740 rpm (Low speed for large diameter) |
| Airflow Volume (Q) | Approx. 60 - 130 m³/s (216,000 - 468,000 m³/h) |
| Static Pressure (P) | Approx. 2000 - 5000 Pa (depending on system resistance) |
| Max Efficiency | 85% - 88% |
| Max Noise Level | < 90 dB(A) (at fan casing, often with silencers) |
Common Applications
- Primary Mine Ventilation (Main Fan): Used at the mine shaft top to extract or supply air to the entire underground mine network.
- High Gas Mines: Ideal for mines with high methane content due to explosion-proof safety features.
- Long-Distance Ventilation: Capable of moving air through long, high-resistance duct systems.
Advantages & Disadvantages
| Advantages | Disadvantages |
|---|---|
| High pressure and efficiency, especially at high resistance. | Higher initial cost compared to single-stage fans. |
| No stator vanes – shorter axial length. | More complex electrical control (two motors must be synchronized in reverse rotation). |
| Excellent reversibility (60-70% efficiency in reverse). | Higher maintenance for two motor bearings. |
| Explosion-proof, safe for coal mines. | Requires careful blade angle adjustment to avoid motor overload. |
Typical Equivalents
This fan is similar in function to:
- BD-II-No21 (Another Chinese counter-rotating series)
- K45-No21 (Chinese mine fan series)
- A series counter-rotating fans from Howden, TLT-Babcock, or other international manufacturers (though specific model numbers differ).
Installation & Operation Notes
- Diffuser Required: A diffuser (expansion section) is installed at the outlet to recover kinetic energy and improve efficiency.
- Blade Angle Adjustment: The blade pitch can be adjusted while the fan is stationary (on some models) or fixed. It must be set to match the mine's required duty point.
- Vibration Monitoring: Vibration sensors are mandatory for large main fans per mining safety regulations (e.g., Chinese AQ standards).
- Start-up Sequence: Usually, the rear impeller starts first, then the front impeller, to reduce electrical load and airflow shock.
Summary: The FBCDZ-6-No21 is a high-capacity, explosion-proof, counter-rotating axial fan with a 2.1-meter impeller diameter, commonly used as a main ventilation fan in large or high-gas underground coal mines.
