Aerovent IM-101 - Manual (Page 2)

ine alignment, complete the assembly, and lubricate the
coupling (when required) before putting the unit into
operation.
Impellers
Fans, which are received factory assembled, have the impellers
already aligned and in place before shipment. However, fans
being flexible to some extent are sometimes subject to move-
ment during shipment. To insure smooth operation and
proper performance, the following impeller alignment should
be checked before putting fan into operation.
Propeller Fans
Fan shaft should be centered and parallel to fan casing. Center
by checking gap (B) between propeller tip and fan casing.
Repeat at three additional points at approximately 90° from
each other (Figure 3b). Parallelism can be observed by measur-
ing the axial distance (A) from one blade to the end of the fan
casing at four points at approximately 90° from each other
(Figure 3a).
Do not confuse parallelism with blade track (axial deviation
of one blade to another). Blade track can be checked by mea-
suring the axial distance from one point on the fan casing to
the same point on each blade as it passes by. (Some blades are
mistracked for balancing.)
While checking the propeller alignment, it is good practice
to check its rotation. Normally the fan rotation is marked by
arrows on both the propeller and the fan casing. If omitted,
obliterated, or misapplied, check for proper rotation in Figure
4a.
Centrifugal Fans
The fan shaft should be approximately centered in the clear-
ance hole in the fan housing and perpendicular to the housing
sides. Perpendicularity can be checked on BI and BIA fans by
measuring dimension “A” (Figure 5) at four points approxi-
mately 90° apart.
Radial blade impellers, material handling, pressure blowers,
and high pressure blowers are centered axially in the housing,
and can be checked by measuring the axial distance from one
blade or one point on the front plate to the side of the fan
housing at four points approximately 90° from each other.
While checking the impeller alignment, it is good practice
to check its rotation. Normally the fan rotation is marked by
arrows on the housing. If omitted, obliterated, or misapplied,
check for proper rotation in Figure 4b.
Figure
3a
Figure
3b
Figure 4a
RH rotation.
Vaneaxial shown.
Standard propellers
similar, but less guide
vanes.
Figure 4b
Figure 5
NOTE: See IM-140 for dimensions.
6MWG09/10
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