Fans by Fantech Electronic Catalogue

P-3

2016

INSTALLATION DO’S AND DON’TS

Figure 1.4. - Duct restrictions at fans

Ducts significantly smaller than the fan diameter create turbulence if transitions connect directly to fan.

An abrupt duct expansion at fan inlet causes air separation from

the duct, starves the impeller tips, creates turbulence, reduces

performance and generates increased noise.

Duct expansions on the inlet to axial flow fans should be

avoided where at all possible.

If essential the transition should have an included angle of not

more than 15°.

1.0 AXIAL FANS (Cont.)

Figure 1.3. - Flexible connection to fan

Flexible connections must be taut or else turbulence at the fan inlet, noise level and pressure loss are all increased.

Slack or misaligned flexible connectors reduce the effective duct

area. This generates turbulence and the blade tips are starved

of air. Fan performance is reduced and noise levels increased.

If flexible connectors are fitted they should be remote from the

fan and ensure they are taut. The air to the impeller tips is then

not obstructed allowing the fan to operate to its optimum and

minimises noise generation.