The core of selecting mining fans lies in air volume, air pressure, explosion-proof performance, high efficiency, safety redundancy, reverse ventilation, and matching the full cycle of the mine’s operation conditions.
1. Core parameter conditions (must be calculated)
1. Mine axial flow fan air volume Q (m³/min or m³/h)
Calculation basis: Calculate the total required air volume of the mine (including personnel, gas, dust, blasting, electrical and mechanical equipment, etc.) according to “MT/T 634—2019”.
Selection requirements:
Main ventilator: Rated air volume ≥ Total required air volume of the mine × (1.05 – 1.1) (leakage, reserve margin).
Local ventilator: Rated air volume ≥ Calculated air volume of the excavation face × 1.1.
Covering the entire cycle: easy ventilation period, difficult period, early stage of reaching production capacity, and later extension.
2. Mine axial flow fan air pressure P (Pa, total pressure)
Calculation basis: Total mine ventilation resistance (friction resistance + local resistance) + influence of natural wind pressure.
Selection requirements:
Main ventilator: Rated total pressure ≥ Maximum ventilation resistance × (1.3 – 1.35) (take the upper limit for high resistance mines).
Local ventilator: Rated total pressure ≥ Total resistance of the air duct × 1.2.
Axial flow / centrifugal matching:
Low resistance (< 1500 Pa), large air volume: Axial flow type (priority for inter-shaft axial flow).
High resistance (> 3000 Pa), deep mine: Centrifugal type.
Medium resistance, complex air path: Mixed flow type.
3. Mine axial flow fan efficiency η
The highest efficiency of the main ventilator ≥ 70%, and the operating condition point should be within the high-efficiency zone.
Prioritize energy-efficient types (such as inter-shaft axial flow, variable frequency speed regulation).
4. Mine axial flow fan power N (kW)
Calculated based on air volume, air pressure, and efficiency: N=
60 × 1000 × η Machine
×η Transmission
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Q×P
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Motor power should have a 10% – 15% margin, and variable frequency motors (energy-saving and speed-adjustable) should be preferred.
Large-capacity main fans can be equipped with dual motors / synchronous motors.
II. Safety and Explosion-proof Conditions (Mandatory)
1. Explosion-proof grade (mandatory for coal mines)
Gas mines: ExdⅠ (mine explosion-proof type).
High gas / outburst mines: ExdⅠMb, and equipped with anti-static impellers and spark-free structure.
All components of the motor, electrical control, and junction box are explosion-proof. Non-explosion-proof equipment is strictly prohibited from entering the mine.
2. Safety redundancy (mandatory for main ventilators)
Two sets of ventilators with the same capacity are provided for each wind shaft (one in use and one as backup), with the same model and specification.
The backup machine starts within 10 minutes.
Local ventilators / ventilator groups must not be used as main ventilators.
3. Reverse ventilation capacity (mandatory)
A reverse ventilation device must be installed, and the wind direction can be changed within 10 minutes.
The reverse ventilation air volume should be ≥ 40% of the normal air volume.
4. “Three Specials and Two Locks” for local ventilators
Special transformers, special switches, special cables; wind power lock, gas power lock.
Air duct: flame-retardant, anti-static, with a leakage rate ≤ 5%.
III. Mine Axial Flow Fan Mine Working Conditions and Environmental Conditions
1. Full-cycle matching of the mine
Covering the air volume / air pressure changes of the first level, second level, and extension stage.
The difference in the equivalent volume holes is large, and the service life is long. Select the type in stages.
2. Natural wind pressure
If the well depth is > 400m or the height difference at the wellhead is > 150m, include the natural wind pressure (±).
3. Environmental adaptability
High dust: wear-resistant impellers, dust-proof sealing.
Damp / corrosive: anti-corrosion coating, stainless steel components.
Noise: low-noise design, muffler, in line with industrial hygiene standards.
IV. Selection Principles and Steps
Calculate the required air volume: calculate the total air volume according to MT/T 634—2019, plus the margin.
Calculate the total resistance: calculate the maximum resistance in the easy / difficult ventilation period, plus the margin.
Select the type: axial flow (large air volume, low resistance), centrifugal (high resistance), mixed flow (medium resistance).
Check the performance curve: the working point should fall in the efficient zone, leave a 5° margin for the axial flow blade angle, and the centrifugal speed should be ≤ 90% of the maximum speed.
Select the motor: explosion-proof, power matching, variable frequency priority.
Safety verification: reverse ventilation, backup, three-specials and two-lock, explosion-proof certification.
Technical and economic comparison: efficiency, energy consumption, maintenance, and lifespan are comprehensively optimized.
