Centrifugal Fan Selection Matters Need Attention by Xianrun Blower---Part 2

Centrifugal Fan Selection Matters Need Attention by Xianrun Blower

5. In the centrifugal fan selection, the most important is long-term economic operation quality and efficiency, other than one-time investment. 

6. In the centrifugal fan selection, be seriously compared with each other, give preference to higher efficiency, samller size, lighter weight, larger adjusting range one. 

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7. For the frequency conversion centrifugal fan, please note that the system calculated total pressure losses are rated pressure, and centrifugal fan power needs to append 15%~20% on calculated value. 

8. Pay attention to the matching relation of pipe system resistant characteristics and centrifugal fan characteristics. For stable operation, centrifugal fan needs to work around the highest efficiency point, and the working point is right of the pressure peak point in the performance curve (in larger airflow side, in general, the working pressure is 80% of pressure peak point). 

Centrifugal fan design point efficiency should not be less than 90% of the highest efficiency. 

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9. For more than one centrifugal blowers working in parallel or in series, it is better to select the same model centrifugal fans. 

Notes To Centrifugal Blower Selection by Xianrun Blower

As we all know, it needs to get much knowledge before choosing a suitable blower. And the selection methods are different according to different selection standard. 

1.According to physical, chemical properties of different gases, it needs to select different fans. Such as, the explosion-proof fan for conveying explosive and flammable gas; 
coal dust fan is used to convey coal dust; corrosion resistant fan for corrosive gas; heat resistant fans are applied in high temperature gas or high temperature situation.

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2. Understanding the centrifugal blower production and quality are necessary before selecting the industrial fans and blowers. Such as the centrifugal fan varieties, specifications and development and promotion of new products, and the requirements of environmental protection.

3. If there are two models centrifugal blower are available in the performance table, it is better to give preference to higher efficiency, smaller size, larger adjusting range.

4. If the ventilation system have requirement for noise, it is better to select high efficiency, low impeller rotational speed fans. And according to the noise and vibration modes of transmission, adopt corresponding noise elimination and vibration reduction measures. Vibration reduction measures of fan and motor includes spring shock absorber or rubber shock absorber, etc.

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5. If the selected fan impeller diameter fan is larger than the original impeller. In order to advantage of the original motor shaft, bearing and supporting, it is necessary to check
the starting time, strength of the original parts and the shaft critical speed.

6. Try to avoid using the centrifugal fan working in parallel or in series. When the inevitable, it needs to select the same model centrifugal fan, with the same performance. 
When using series operation, there should be certain pipeline connection between the first level fan and second level fan.

7. The new selected fan should make full use of existing equipment, and be suitable for on-site installation and in safe operation.

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How to select the suitable centrifugal fan? The 2nd Stage by Xianrun Blower

Centrifugal Blower Selection Process by Xianrun Blower

The 2nd Stage of Selection:

The centrifugal fan model determines the performance curve, performance curve can be divided into dimensioned curve and dimensionless curve. 

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Dimensioned curve is the basis to decide whether the centrifugal fan can meet the site requirements, while the dimensionless curve is the basis of depicting the fan performance. The dimensioned curve represents the particularity, dimensionless curve represents the universality.

In general, the dimensionless parameters are the airflow coefficient, pressure coefficient, the efficiency, specific speed. 

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Airflow coefficient, pressure coefficient are the basis for calculating fan model; specific speed is the basis to select the fan model; the efficiency is to determine whether the centrifugal fan have high efficiency.

According to the specific speed, to select the fan model and determine whether the working points are in high efficient area. If the points are in high efficient area, it needs to preliminary calculation fan model according to airflow coefficient and pressure coefficient.

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