FBCDZ-6-No13 Coal Mine Exhaust Explosion-Proof Counter-Rotating Axial Flow Fan

This article's table of contents introduction:

1. Model Breakdown
2. Full Description: FBCDZ-6-No13
3. Key Features & Technology
4. Technical Specifications (Approximate for this model)
5. Application & Installation
6. Summary

This is a specific model designation for a heavy-duty industrial fan used in underground coal mining ventilation. Here is a breakdown of what the model number FBCDZ-6-No13 means, along with the key features implied by the description.

Model Breakdown

• F = Fan
• B = Explosion-Proof (防爆)
• C = (Typically) Counter-Rotating or "Forced" depending on the specific Chinese standard, but in this context (Exhaust + Counter-Rotating) it means Vertical installation (or "Shaft" type) for mine use. More accurately, in the standard MT/T 754-2005, 'C' stands for a vertical (shaft) installation configuration.
• D = Electric Motor Direct Drive (the impellers are mounted directly on the motor shafts, no belts or long shafts).
• Z = This is context-specific. In many Chinese fan naming conventions, this can denote a specific design feature like a diffuser, silencer, or a particular blade profile (e.g., 'Z' for 直板/Straight blade or 轴流式/Axial flow). In the FBCDZ series, it generally refers to the fan being part of a specific standardized series with a diffuser cone.
• 6 = Pole Number of the Motor (The motor runs at 6 poles, nominal speed ~980-990 RPM for a 50Hz power grid).
• No13 = Impeller Diameter (The fan impeller is 13 decimeters in diameter, which is 3 meters).

Full Description: FBCDZ-6-No13

Primary Function: This is a main mine ventilation fan designed for exhaust (suction) service. It is placed at the top of a mine shaft or at a surface opening to draw stale, contaminated air (methane, dust, etc.) out of the underground workings.

Key Features & Technology

• Counter-Rotating Axial Flow:
  • This fan has two impellers (rotors) that rotate in opposite directions.
  • There are no stationary guide vanes between the impellers.
  • Air enters through the 1st rotor, gets accelerated, and then passes directly into the 2nd rotor (spinning the opposite way). The 2nd rotor acts as a stator/rotor combination, straightening the airflow and recovering rotational energy. This principle provides very high efficiency (up to 85%+) and high pressure generation for a single axial fan stage.
• Explosion-Proof (B) :
  • The fan casing and motor enclosures are designed to contain any internal methane gas explosion, preventing it from igniting the surrounding atmosphere.
  • The impellers are made of brass or aluminum alloy (non-sparking) to prevent frictional sparks against the steel casing.
• Direct Drive (D) :
  • The two impellers are directly mounted on the shafts of two separate, specially designed explosion-proof motors housed within the fan cylinder.
  • Advantage: No belts, pulleys, or bearings to maintain in the airstream. High reliability and no power loss from mechanical transmission.
• Reversible Ventilation:
  • A critical feature for mining. Because it is counter-rotating, the fan can achieve reverse airflow simply by swapping the electrical phases of one or both motors. This changes the rotation direction of the impellers, effectively reversing the airflow path.
  • Important: In reverse mode, the efficiency and pressure are lower than in forward mode, but it is sufficient for emergency anti-reversal operations (preventing gas from back-flowing into the mine). Typically, reverse airflow can reach 60-70% of the forward volume flow rate.

Technical Specifications (Approximate for this model)

Note: Actual performance depends on the specific blade angle setting (adjustable in most models).

Application & Installation

• Location: Installed on the surface at the exhaust air shaft head.
• Configuration: Often installed in a vertical orientation (shaft outlet) or in a horizontal bypass duct system with isolating doors.
• Backup: Typically installed in a pair (A & B fans) with isolating dampers. One operates while the other is on standby.
• Regulation: Speed can be controlled via Variable Frequency Drives (VFDs) for energy savings, or blades can be adjusted on the impellers (if designed for pitch adjustment).

Summary

The FBCDZ-6-No13 is a robust, high-efficiency, explosion-proof axial fan specifically built for the demanding task of primary mine ventilation. Its counter-rotating direct-drive design offers high pressure, simple reversal (critical for safety), and minimal maintenance compared to old-style centrifugal fans or belt-driven axial fans. It is a standard choice for medium to large-sized coal mine ventilation systems.