Mine ventilation fan

Mine fans are the core equipment of the mine ventilation system, known as the "respiratory system" of mines. They are specifically designed for underground ventilation in coal mines and metal/non-metal mines. Mine-entry fan models must be certified with MA coal safety certification and flameproof and explosion-proof design, used to deliver fresh air, exhaust gas, carbon monoxide, dust, and blasting fumes, ensuring the safety of personnel underground and preventing gas and coal dust explosion accidents.

1. Core functions

1. Supply fresh air to meet the breathing needs of personnel underground

2. Dilute and exhaust toxic and harmful gases such as methane and CO to prevent methane accumulation and explosion

3. Discharge rock dust and coal dust, reduce the risk of pneumoconiosis, and suppress coal dust explosions

4. Regulate temperature and humidity underground; the main fan is equipped with a wind reversal function, which can reverse the airflow in case of a fire accident, facilitating disaster relief and risk avoidance

II. Three major categories (by purpose)

1. Main fan (main ventilator, FBCDZ/BFK series, ground-based machine room)

The entire mine or mining area is subject to general ventilation, operating continuously for 24 hours. Random shutdowns are strictly prohibited, and reversing the airflow is allowed.

It is mostly a counter-rotating axial flow fan with adjustable blade angles; it features high air volume and high wind pressure

Coal mines must be explosion-proof, with two machines in operation and one standby, equipped with air doors, mufflers, and monitoring systems

Application: Main shaft air return in coal mines, surface air exhaust in large metal mines

2. Local ventilation fan (local fan, underground heading face, FBD/FBCD)

Specially designed for tunneling in single-end tunnels, it is equipped with an air hose for air supply and is a standard configuration for mining and excavation work sites

FBD: Press-in counter-rotating local fan, delivering fresh air into the heading (main flow in low-gas tunnels)

FBCD: Extractable counter-rotating local fan, which directly extracts gas-laden and contaminated air. For high-gas and outburst mines, the counter-rotating structure is mandatory: two-stage impellers rotate in opposite directions, providing high wind pressure and long-distance air supply, with one in operation and one as standby

3. Auxiliary ventilator (auxiliary fan, K40/K45)

Pressurization and adjustment of pipe network resistance in underground tunnels are commonly used in metal mines to balance the airflow in tunnels

For metal mines without gas, ordinary K series axial fans can be used; for coal mines, all fans must be flameproof ExdI, and ordinary industrial fans are strictly prohibited from entering the mine

III. Structural form

1. Counter-rotating axial flow (mainstream for mining applications): Two sets of impellers rotate in opposite directions without complex flow guidance, resulting in high wind pressure and efficiency. It is widely used in main fans and local fans

2. Single-stage axial flow (K40/K45): simple structure, adjustable blade angle, commonly used for main ventilation in non-coal mines

3. Mining centrifugal fan: high wind pressure, bulky and heavy, now less used in mines

IV. Core Security Requirements (Key Points)

1. MA coal safety mark: mandatory qualification for underground coal mine equipment. Without MA, equipment cannot be used underground

2. Flameproof and explosion-proof motor ExdⅠ: The enclosure can withstand internal explosion pressure, and sparks will not ignite external gas; for metal mines, ExdⅡBT4 is selected according to the working conditions

3. The air duct is flame-retardant and anti-static; the entire machine is wear-resistant and suitable for dusty environments

4. The main fan must be equipped with two standby units, capable of online monitoring and switching without stopping the fan; the local fan must be equipped with wind and gas electric interlocking

V. Supporting Components (All accessories mentioned earlier can be matched)

Explosion-proof motor, impeller, inlet air regulating valve, silencer, inlet and outlet flexible connection, shock absorber, coupling, shield, explosion-proof frequency converter, monitoring instrument, air duct, diffuser.

VI. Key parameters for model selection

1. Mine type: coal mine (explosion-proof MA)/metal mine (ordinary type)

2. Air volume, total pressure, and total resistance of the tunnel

3. Installation location: ground main fan / underground local fan; forced entry type or extraction type

4. Transmission medium: gas concentration, dust, temperature

5. Power supply: 6kV/380V, with or without frequency control and online monitoring

6. Anti-wind demand (essential for main fan)

VII. Common faults

1. Ash accumulation and wear on the impeller disrupt the dynamic balance, resulting in excessive vibration

2. Rusting of explosion-proof surface, leading to explosion-proof failure (a major hidden danger in coal mines)

3. Local fan circulation, air duct leakage, insufficient headwind volume, and gas exceeding limits

4. Overheating of the bearing and damaged seal