The main point fan selected by the centrifugal fan is different from other products. The use time is generally in several years, even more than ten years, and the axial centrifugal fan is also high and low. Therefore, when we choose the centrifugal fan, we must choose the suitable and high cost centrifugal fan. First of all, according to the two basic parameters of the fan's air volume and wind pressure, the model and number of the fan and the required power are determined through the performance table of the fan, and the required power is determined. At this time, there may be more than one product to meet the requirements; we will combine the use of the fan, the process requirements, and the operating conditions. In order to make the rated flow and pressure of the fan as close as possible to the flow and pressure required by the process, the operating conditions of the fan are close to the high efficiency area of the fan's characteristic.
具體原則如下：The specific principles are as follows:
Before selecting the fan, we should understand the production and product quality of the domestic centrifugal fan, such as the variety, specification and special use of various products, and understand the current domestic fan market.
According to the different physical and chemical properties of centrifugal fans conveying gas, choose different types of centrifugal fans. For example, the selected explosion-proof centrifugal fan, which carries explosive and flammable gas, determines the requirement for the explosion protection grade of the fan; the dust or the pulverized coal should be selected for the dust or pulverized coal centrifugal fan; the corrosion resistant gas should be selected as the anticorrosion centrifugal fan, and the antiseptic material is PP, and so on. High temperature gas should be selected by high temperature centrifugal fan, and environmental temperature and gas temperature should be understood.
When there are more than two centrifugal fans on the centrifugal fan selection performance chart, there are more than two centrifugal fans to choose. They should choose a higher efficiency, smaller number and a larger adjustment range, and of course, it can also compare the price ratio and weigh the advantages and disadvantages.
If the diameter of the selected fan impeller is much larger than the diameter of the original fan, in order to make use of the original motor shaft, bearing and support, the starting time of the motor, the strength of the original parts of the fan and the critical speed of the shaft must be calculated.
When selecting the centrifugal centrifugal fan, when the motor power is less than or equal to 75KW, no valve can be installed for start-up. When the high temperature flue gas or air is discharged and the centrifugal boiler induced draft fan is selected, a starting valve should be set up to prevent overload during cold running.
6. For the ventilation system with noise requirements, a centrifugal fan with high efficiency and low circumferential velocity of the impeller should be selected first, and it works at the highest efficiency point, and corresponding measures of noise reduction and vibration reduction should be taken according to the transmission mode of noise and vibration produced by the ventilation system. Vibration reduction measures for centrifugal fans and motors are generally available. Different damping devices are selected according to different installation modes of fans.
When selecting a centrifugal fan, it is important to avoid using centrifugal fans in parallel or in series. When it is unavoidable, axial fans should choose the same type and homosexual centrifugal fans. When connected in series, the first stage centrifugal fan should have certain pipe connection between the second centrifugal fans.