This article's table of contents introduction:
Based on the product model name you provided: FBCDZ-8-No27 Coal Mine Exhaust Explosion-Proof Counter-Rotating Axial Flow Fan
Here is a detailed breakdown of what this model number signifies, its features, specifications, and typical applications.
Model Breakdown
F: Fan
B: Explosion-proof (防爆)
C: Counter-rotating (对旋)
D: Motor directly connected (电机直联)
Z: Axial flow (轴流)
6: Design number or performance series number
No27: Impeller diameter in decimeters → 27 dm = 2,700 mm (2.7 meters) wheel diameter
Coal Mine Exhaust: Primary application (underground coal mine main ventilation / exhaust).
Explosion-Proof: Motors and components are rated for use in explosive gas environments (e.g., methane/coal dust).
Counter-Rotating Axial Flow: Two impellers rotating in opposite directions (no stator vanes needed, high efficiency).
Key Features
| Feature | Description |
|---|---|
| Explosion-Proof Design | Motors and electrical components are enclosed in flameproof enclosures (Ex d) per Chinese GB standards (e.g., GB3836). Suitable for Group I (mining) gases. |
| Counter-RotatingImpellers | Two-stage impellers rotate in opposite directions. The rear impeller recovers the swirl energy from the front impeller, generating higher pressure without requiring guide vanes. |
| Direct Drive (Motor Directly Connected) | No belts or couplings. Impellers are mounted directly on the motor shafts, reducing maintenance and increasing reliability. |
| Reversible Operation | Counter-rotating fans can achieve approximately 60-70% of forward airflow in reverse, which is critical for emergency exhaust or reversal of ventilation direction. |
| High Efficiency | Typically operates in the 80-85% efficiency range at the design point. |
| Steep Pressure Curve | Suitable for mine ventilation systems with varying resistance (e.g., longwall face ventilation). |
Technical Specifications (Approximate for No27)
| Parameter | Typical Value |
|---|---|
| Impeller Diameter | 2,700 mm (2.7 m / 106 inches) |
| Air Volume (Q) | 60 – 150 m³/s (depending on speed and blade angle) |
| Static Pressure (P_sf) | 1,500 – 4,500 Pa (depending on speed and blade angle) |
| Motor Power | 2 × 250 kW to 2 × 450 kW (two motors, one per stage) |
| Motor Speed | Typically 740 rpm or 990 rpm (6-pole or 8-pole) |
| Voltage | 380V / 660V / 1140V (mining standard) |
| Noise | ≤ 85 dB(A) at 1m (with silencer) |
| Operating Temperature | -20°C to +40°C |
Application
Primary Use: Main exhaust fan for underground coal mines.
Used to extract foul air (methane, dust, fumes) from the mine via the return air shaft.
Explosion-proof Requirement: Mandatory in coal mines with potential methane (CH₄) or coal dust explosion hazards.
Counter-rotating Advantage: Provides high pressure (needed for deep mines) while maintaining high efficiency and compact axial length.
Advantages over Conventional Axial Fans
| Aspect | FBCDZ (Counter-rotating) | Conventional Single-stage Axial |
|---|---|---|
| Pressure Generation | High (up to 4500 Pa) | Moderate (up to 2500 Pa) |
| Efficiency | Higher (no stator losses) | Moderate (stator vanes cause loss) |
| Reverse Flow | ~60-70% of forward flow (reversed by changing blade pitch or reversing one motor) | Typically 40-50% of forward flow (requires reversible blades or dampers) |
| Length | Longer (two motors + two impellers) | Shorter (one motor + impeller) |
| Maintenance | Two motors to maintain | One motor |
Applicable Standards (China GB)
GB/T 21151-2007: Axial flow fans for coal mines
GB 3836.1-2010: Explosive atmospheres – General requirements
GB 3836.2-2010: Explosive atmospheres – Flameproof enclosures “d”
AQ 1011-2005: Coal mine fan structure safety requirements
MT 222-2007: Technical conditions for mining fans
Typical Installation Diagram
[Air inlet] → [Silencer] → [Front motor + Impeller (Stage 1)] → [Rear motor + Impeller (Stage 2, reversed rotation)] → [Diffuser] → [Exhaust stack to atmosphere]
The front impeller rotates clockwise (viewed from inlet).
The rear impeller rotates counter-clockwise.
Both impellers have adjustable blade angles (stopped or with adjustable pitch).
Important Notes
Blade Angle Adjustment: To change performance (air volume/pressure), the blade angle of both stages must be adjusted symmetrically. Some newer models allow hydraulic or electric pitch adjustment while running.
Explosion-proof rating: The two motors are separately flameproof certified (Ex d I Mb). Cable entry boxes are also explosion-proof.
Vibration Monitoring: Typically equipped with bearing temperature sensors and vibration transducers (connected to mine-wide monitoring system).
Lubrication: Bearings are grease-lubricated; some large models have oil-lubricated bearings.
Manufacturer Examples (Chinese Brands)
Shaanxi Blower (Shaangu)
Zibo Huaxiang Fan Co., Ltd.
Yantai Longyuan Power Technology
Wenzhou Yongjia Blower
If you need a specific performance curve, blade angle recommendations, or motor specification sheet, I can help calculate or source typical data for the No27 size. Let me know your required air volume and static pressure!
