In some engineering applications, sometimes only one centrifugal fan equipment may not be able to meet the production requirements, so it is necessary to combine two or more centrifugal fan equipment in series. Similar to centrifugal pumps, the series connection of centrifugal fans can increase the wind pressure or adopt parallel connection mode, which can increase the flow rate.
What exactly is serial operation? The operation mode of conveying gas to a pipeline by connecting two, or more than two centrifugal fans end to end is called series operation. Generally, when connecting in series, one of them is usually placed in front of the device and the other is placed behind the device. In the air conditioning system, the series system of this kind of fan is formed when the fan is set in the blastpipe channel and the return air pipe respectively. If the two fans are the same, when running in series, the air volume in the whole system is equal to that of each fan, and the wind pressure is the sum of the two.
Under such working conditions, the operating characteristic curve of centrifugal fan equipment running in series can be obtained according to the vertical superposition of wind pressure under equal flow rate. Therefore, when the two fans run in series, the wind pressure in the system increases, so that each fan has sufficient capacity to send more gas into the pipeline, the air volume QC of each fan after series connection is greater than the air volume QB when a single fan is opened, while the air pressure is just the opposite.
If the wind pressure needs to be effectively increased, then the series suggestion about centrifugal fan equipment is applied in the pipeline with higher resistance, because the greater the resistance of the pipeline, the steeper the characteristic curve of the pipeline system, the better the supercharging effect is; Otherwise, a good supercharging effect will not be obtained.
It should be noted that when two centrifugal fan equipments with different working efficiency are operated in series, they must be considered thoroughly. In addition, for the series connection of large and small centrifugal fans, big fan must deliver gas to small fans. If it is installed in reverse, the suction inlet of big fan will have insufficient air flow and low air pressure, the connected fan cannot work properly.
