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P-7
© FANTECH
2016
INSTALLATION DO’S AND DON’TS
INSTALLATION DO’S AND DON’TS
Figure 2.4. - Eccentric inlet flow
Do ensure inlet air to the fan is evenly distributed.
Eccentric air distribution at fan inlet diminishes fan performance
by up to 45% because the main flow is accelerated through an
effectively smaller duct area on one side while turbulence and
high intensity pressure fluctuations occur on the other.
Noise level is also increased.
Rated fan performance is only achieved when air flows evenly
into the fan impeller.
A poorly designed inlet box can generate spinning of the air
which can reduce performance by around 25%.
Also, avoid small inlet boxes as they can cause surging.
Splitters at the inlet help prevent spinning flow. Turning vanes,
where R/W<1.0 improves uniformity of flow approaching the fan
inlet.
Inlet boxes should be amply sized.
P
2.0 CENTRIFUGAL FANS (Cont.)
Figure 2.3. - Spinning of air at inlet connection
Ensure spinning of air at fan inlet does not take place