Negative-Pressure Fan Working Principle

1. Ventilating Principle

The negative-pressure fan is used to exhaust air indoor, so the indoor air pressure is lowered, then there is a negative-pressure zone and the air outdoor will flow into the house for the air pressure difference;

2. Cooling Principle

A. Cooling by air exchange: the fan exhausts the hot air indoor to even the temperature between indoor and outdoor;
B. Combine with the evaporative cooling pad to reach a good ventilating-cooling effect.

Negative-Pressure Fan Routine Maintenance

1. Regularly clean and maintain fan blades and shutters;
2. If the belt has loosened, it should be adjusted and reset in time;
3. Add lube if the motor bearing makes strange sounds;
4. Regularly check the motor to ensure its good working condition.

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  Important Terms for Fan Selection Principle

  • Air Delivery: It is the amount of air that a fan will move under different conditions; also expressed as volume of air movement per unit time and the standard unit is cubic feet per minute (cfm).
  • Static Pressure: It is the pressure difference that a fan creates between the inside and outside of a mechanically ventilated structure. Fans create a vacuum in a house by exhausting air. The indoor environment with a lower pressure than outdoors will draw air in. This is a negative pressure system.
  • Fan Efficiency: It is the air delivery amount that a fan will provide per unit of electricity used and the standard unit is cubic feet per minute per watt (cfm/W).