Adjusting Fan Blade Pitch - SPX Cooling Technologies COFIMCO 03-11A User Manual

Note
Figure 4
Table 5

Adjusting Fan Blade Pitch

The trial pitch is the calculated setting for design conditions
(water rate , heat load, air density, and brake horsepower). The trial
pitch is provided by SPX (see page 2).
1–Select a position on the fan circumference and rotate each blade
to this common location when setting or checking blade pitch. Sup-
port the blade tip to maintain a common rotation plane while setting
the fan pitch. The pitch is set
by placing a protractor on top of a parallel sided straight edge that
extends across blade width as shown in Figure 4.
2–Be sure all blades are positioned correctly on hub, then set the
pitch. Blades should be within ±
the desired setting is obtained, progressively tighten the hardware
according to Table 5. Recheck the pitch angle. If required, loosen
the hex nuts and reset the pitch as necessary until the proper pitch
angle is obtained.
Bolt
Diameter
⁄ "
3
8
⁄ "
5
8
⁄ " (5 mm) inboard of the blade tip
3
16
⁄ ° of the desired pitch angle. After
1
4
Torque Wrench Setting
ft·lb N·m
ƒ
40 55
100 136
5