Fans by Fantech Electronic Catalogue

2016

Figure 2.2. - Bends on fan discharge

Bends near fan discharge should be in the direction of wheel rotation to prevent needless pressure loss.

Air moves faster at the outside of the fan housing and is not

evened out before striking the abrupt bend. A very high

pressure loss results.

Improved discharge arrangement with radiused bends and

splitters or different fan mounting position will reduce system

losses.

Bends should ‘rotate’ in the same direction as the impeller.

2.0 CENTRIFUGAL FANS

Figure 2.1. - Pressure recovery

Look for opportunities for pressure recovery at centrifugal exhaust fan outlets.

To determine the system resistance the discharge losses have

to be added before selecting the fan.

Discharge losses are highest in this arrangement and are

equivalent to one velocity head.

With a correctly designed discharge diffuser the pressure

recovery in the diffuser will reduce the system total pressure.

Included angle of diffuser to be 15° or less.

Discharge losses reduced by up to 75% in this arrangement.

INSTALLATION DO’S AND DON’TS

P-6