Characteristics:
Negative pressure fans are a modern ventilation solution, primarily used in negative pressure ventilation and cooling systems. These systems address both ventilation and cooling simultaneously. Beyond negative pressure applications, these fans are also utilized in positive pressure evaporative air conditioning systems, positive pressure air supply, and positive pressure blowing applications. They are a type of axial flow fan and are characterized by their large size, expansive air ducts, large fan blade diameters, high exhaust volume, low energy consumption, low speed, and low noise levels.
Key Applications:
Exhaust Ventilation: Installed on the exterior of workshop windows, typically on the downwind side, to extract stale air and odors. Commonly used in factories and industrial settings.
Cooling with Evaporative Cooling Pads: Used in conjunction with evaporative cooling pads (wet curtains) to lower workshop temperatures. This system can reduce temperatures to around 30°C (86°F) while maintaining a certain level of humidity, even in hot summer conditions.
Noise Reduction Methods:
Vibration Isolation:
Focus on vibration isolation of the motor and casing. Use rubber vibration damping pads or spring isolators to isolate the rigid connection between the motor and casing and the supporting structure.
Ensure flexible connections are used where the fan connects to the wall or roof to reduce vibration transmission.
Fan Blade Optimization:
Replace with low-noise fan blades, which typically use optimized aerodynamic profiles to reduce air turbulence.
Casing Soundproofing:
Attach sound-absorbing materials (such as sound-absorbing cotton or soundproofing felt) inside the casing to reduce casing resonance and noise radiation.
Duct Design:
Optimize duct design to reduce air resistance and turbulence, thereby reducing wind noise.
Add sound-absorbing materials to the inner walls of the duct.
Installation Location:
Install in a location as far away as possible from areas that require quiet.
2. Fiberglass Bell-Mouth Negative Pressure Fans:
Characteristics:
The bell-mouth design helps improve airflow and reduce air resistance.
Fiberglass material has good corrosion resistance and some sound absorption properties.
Commonly used in locations with higher noise requirements, such as livestock farms and greenhouses.
Noise Reduction Methods:
