Axial Flow Fans, Wind Power Specialty Fans

Centrifugal fans(hereinafter referred to as fans)are low,medium,and high-pressure fans with a wide range of applications.They feature a flat pressure curve,are easy to install and maintain,and have low manufacturing costs.In today's market with numerous fan types,they are primarily used for ventilation and air exchange in general factories,warehouses,high-rise buildings,subways,and other large structures.They are frequently found in critical and high-stakes locations such as the Beijing Subway,where crowds are dense and safety is paramount.They can either exhaust or supply air,but the conveyed gas must be air or other non-combustible gases.

The gas must be non-volatile,non-explosive,non-corrosive to steel,and harmless to the human body.It must not contain sticky substances.The proportion of dust and hard particles in the conveyed gas must not exceed 150mg/m³,and the temperature of the conveyed gas must not exceed 80°C.

B Centrifugal fans,also known as explosion-proof centrifugal fans(designated by"B"),can convey flammable,explosive,and volatile gases.Their aerodynamic performance,external dimensions,foundation dimensions,and internal structure are identical to the LF-47 model of the same frame size.However,the power source must be an explosion-proof motor,and the impeller must be made of aluminum material.This is to prevent sparks caused by impeller imbalance rubbing against the housing.Switches should be explosion-proof or located away from ignition sources to prevent sparking during operation.In explosion-prone areas,all electrical wiring must have no joints to prevent"loose connections"that could cause sparks,and wires should be enclosed in conduit.

Centrifugal fans are commonly used in mines,tunnels,chemical plants,and similar environments.

Centrifugal fans may be required to convey gases that are corrosive to steel,harmful to humans,or toxic.For such applications,all components that come into contact with the conveyed gas,such as the housing,impeller,air inlet,and air outlet,must be made of corrosion-resistant materials,such as stainless steel,fiberglass,or other anti-corrosion materials.Their aerodynamic performance,external dimensions,foundation dimensions,internal structure,and power source...

They are frequently used in critical applications such as chemical plants,galvanizing plants,and fertilizer plants.

Type Designations

Typically,centrifugal fans are available in over 30 models and more than 100 varieties,including 
sizes:2.8A,3.2A,3.6A,4A,4.5A,5.6A,6A,6C,6D,8C,8D,10C,10D,12D,16B,20D~30D,20F~30F.Any of these frame sizes,with any drive arrangement,can be configured for either"left"or"right"rotation.When viewing the impeller from the motor side,clockwise rotation is designated as"right-hand fan"(indicated by"right"),and counter-clockwise rotation is designated as"left-hand fan"(indicated by"left").

The discharge port position of the fan is indicated by the outlet angle of the housing.Users can install it in the required position based on their needs;no specification is needed at the time of ordering.

Special Notes:

①For No.2.8A,the air outlet adjustment range is 0°to 225°,in 45°increments.

②For No.3.2A to 6A,6C,6D,the air outlet adjustment range is 0°to 225°,in 22.5°increments.

③For No.8D to 10C,D,the air outlet adjustment range is 0°to 180°,in 45°increments.

④For No.12C,D,the air outlet adjustment range is 0°to 180°,in 15°increments.

⑤For No.16B,20D,the air outlet angles are fixed at 0°,90°,and 180°and cannot be adjusted.The desired angle must be specified when ordering.

⑥The above outlet angles are industry conventions.If these options do not meet your specific usage environment and conditions,our factory can manufacture the fan with your desired angle.In such cases,the installation dimension tables later in this manual may change,so users should pay attention to this.

The drive arrangements for fans are designated as A,B,C,D,E,F:

A—Indicates the fan shaft is mounted directly onto the motor shaft extension via a keyway(direct motor drive).

B—Indicates overhung support with belt drive,where the pulley is located between the two bearings.

C—Indicates overhung support with belt drive,but the pulley is located on the outside of the bearings.

D—Indicates overhung support driven by a coupling.

E—Indicates support between bearings(double support)with belt drive,where the pulley is located on the outside of the bearings.

F—Indicates support between bearings(double support)driven by a coupling.

These drive arrangements generally meet user requirements.If,however,they do not meet your specific needs,our factory has the capability to design and manufacture a fan to your satisfaction.

Structure

The fan mainly consists of an impeller,housing,air inlet,and drive components.However,models No.2.8 to 6A use A-drive and do not have a separate drive assembly.

Impeller—This is the core component of the fan.Its material and blade profile determine the fan's pressure,airflow,energy consumption,noise,and lifespan.This fan features ten backward-inclined airfoil blades...(sentence incomplete in original)...ensuring smooth and reliable operation and good aerodynamic performance.

Housing—The housing is manufactured in two different types:Housings for models No.2.8 to 12 are made as a single,non-split unit.Housings for models No.16 to 30 are split horizontally into upper and lower halves,with the upper half further divided vertically along the centerline and connected by bolts.This design facilitates disassembly,maintenance,and movement.The specific material is based on the fan's application,fabricated from either ordinary steel plate,stainless steel,or fiberglass reinforced plastic.The manufacturing process,cost,and production time vary accordingly.

Air Inlet—The air inlet is constructed as a single unit.Its cross-section parallel to the axial direction has a curved shape,designed to allow gas to enter the impeller smoothly with minimal loss.The air inlet is typically bolted to the fan casing on one side.The radial and axial clearances between the inlet and the impeller are critical.If too small,friction may occur;if too large,air leakage can happen,affecting efficiency.Please ensure the design dimensions are maintained.

Drive Assembly—The drive assembly consists of the main shaft,bearing housing,rolling element bearings,and either a pulley or coupling.

Performance

Fan performance is typically expressed using parameters such as flow rate,total pressure,shaft speed,shaft power,and efficiency.There are specific conversion relationships between these parameters,which can be represented by performance curves,mathematical formulas,or tables.

Let:

Q—Flow rate(m³/h)

H—Total pressure(Pa)

N—Shaft power(kW)

n—Total pressure efficiency(%)

n-m—Mechanical efficiency(%)

r—Density(kg/m³)

n—Shaft speed(r/min)

t—Temperature(°C)