Aerovent IM-100 - Manual (Page 7)

Aerovent IM-100 7
Centrifugal Fan Alignment
The fan shaft should be approximately centered in the
clearance hole in the fan housing and perpendicular to
the housing sides.
Adjust the clearance by moving the wheel axially
on the shaft. The following table indicates the correct
measurements for positioning the BI and BIA wheels.
Proper positioning is important in attaining correct fan
performance, particularly on the BI and BIA wheels.
Type CB & CBA (SWSI Units)
“B” dimension must be held. This dimension is critical
to fan performance.
Type BIUB
Type CA, BW, OW, PB & HPB
These radial blade wheels do not require precise posi-
tioning to attain the correct performance. The important
thing is to centrally locate these wheels axially within
the housing to insure adequate running clearance and
to maintain concentricity with the fan inlet.
Type AW
These wheels require a special inlet on the housing
which must extend into the wheel inlet flange to per-
form properly. Other than maintaining a minimum 1 ⁄
4
"
overlap, adequate running clearance and concentricity
are all that is required.
Type FC
The forward curve blower employs a shallow venturi in
the housing to guide the air into the wheel. The depth
of this venturi is approximately one-tenth the wheel
diameter. Clearance between the wheel and venturi
should be the smallest allowable and still maintain nor-
mal running clearance. This axial separation is approxi-
mately 1 ⁄
4
" and should be measured at four points
approximately 90° apart.
Installation Instructions for
Propellers Equipped with
Browning Malleable Iron Split
Taper Bushings
Many Aerovent fans are furnished with split taper bush-
ings for mounting the propeller to the shaft. When
properly assembled, the bushings grip the hub with
positive clamping action.
1. The bushing barrel and the bore of the propeller are
tapered. This assures concentric mounting and a true
running propeller.
2. Capscrews, when tightened, lock the bushing in the
propeller. Use special plated capscrews threaded full
length furnished by Aerovent.
3. The bushing is split so that when the locking cap-
screws force the bushing into the tapered bore, the
bushing grips the shaft with a positive clamping fit.
This will withstand vibration and punishing loads
without being loosened.
4. The propeller and bushing assembly is keyed to the
shaft and held in place by compression. This gives
added driving strength.
Before assembly, be sure that the shaft and key-
way are clean and smooth. Check the key size with
both the shaft and bushing keyways.
5. To assemble, put the capscrews through the clear-
ance holes in the bushing and put the bushing
loosely into the propeller. Do not press or drive. Start
the capscrews by hand, turning them just enough
to engage the threads in the tapped holes on the
propeller. Do not use a wrench at this time. The
bushing should be loose enough in the propeller to
move slightly. Slide the propeller and bushing assem-
bly onto the shaft, making allowance for end play
of the shaft to prevent rubbing. Install the key into
the keyway. Do not force the propeller and bushing
onto the shaft. If it does not go on easily, check the
shaft, bushing and key sizes once again.
Tighten the capscrews progressively with a wrench.
Do this evenly as in mounting an automobile wheel.
Tighten each capscrew part of a turn successively until
all are tight. These capscrews force the taper bushing
into the hub which in turn compresses the bushing onto
the shaft. This makes a positive clamping fit. The torque
must not exceed that shown in the table on page 8.
WARNING: Do not attempt to pull the bushing flange
flush with the hub end. There should be a clearance
which varies approximately 3 ⁄
16
" to 1 ⁄
4
" with the bush-
ing size when tightened. (Note: This is not a locating
dimension.)
A
DIA
B
B
A
DIA.
C
Inlet Cone
Wheel
SIZE A B C
12 12.25 0.32 4.28
14 13.50 0.34 4.84
15 15.00 0.38 5.38
16 16.50 0.44 5.81
18 18.25 0.56 6.44
20 20.00 0.63 7.00
22 22.25 0.69 7.84
24 24.50 0.75 8.63
27 27.00 0.88 9.47
30 30.00 0.97 10.56
33 33.00 1.06 11.63
36 36.50 1.10 13.03
CB & CBA SWSI Wheel Placement
Size 122 135 150 165 182 200 222 245 270 300 330
A 12.25 13.50 15.00 16.50 18.25 20.00 22.25 24.50 27.00 30.00 33.00
B 0.32 0.34 0.38 0.44 0.56 0.63 0.69 0.75 0.88 0.97 1.06
Size 365 402 445 490 542 600 660 730 807 890
A 36.50 40.25 44.50 49.00 54.25 60.00 66.00 73.00 80.75 89.00
B 0.94 1.03 1.13 1.25 1.38 1.56 1.69 1.88 2.09 2.28