SB--7--627 Page 16
Gear End Clearance
Gear
Min.
Dia. In.
1008 to 1016
.006
.015
1018 to 1030
.007
.018
12
.007
.018
14
.008
.020
16
.009
.023
18
.009
.023
20
.010
.025
22
.011
.028
Torque Requirements
Timing Gear Cap Screws
Gear
Ft. Lbs.
Nm
Dia.
Torque
Torque
10
70 -- 100
95 -- 136
12
160 -- 225
217 -- 305
14
210 -- 350
285 -- 475
16
250 -- 350
339 -- 475
18
250 -- 350
339 -- 475
20
400 -- 500
542 -- 678
22
400 -- 600
542 -- 813
In.
CM
FIGURE 10 -- GEAR END CLEARANCE
FIGURE 11 -- TORQUE REQUIREMENTS -- TIMING GEAR
CAP SCREWS
Determining
Proper
Impeller
Clearances
(FIGURE 12) -- The clearances between impellers are
measured at points 0--0 and c--c when the impellers are
in the positions shown. Note that the impellers are
shown viewed from the drive end of the blower; always
face the drive shaft end when determining clearance.
Select the illustration from the sketches which is
applicable to your unit.
If the drive shaft is on the right side of centerline, it is
a ‘right hand’ unit; if it is on the left, it is a ‘left hand’ unit.
For vertical units: if the drive shaft is on the bottom side
of the center line, it is a ‘bottom hand’ unit. Check
above the drive shaft for a rotational arrow. If the arrow
appears, the unit is timed for rotation only in that
direction. If no arrow appears, it is ‘center timed’ for
rotation in either direction.
To determine total clearance, place the impellers in the
0--0 position. Measure the distance between 0--0 with
a feeler gauge. Rotate the impellers 90
_
to position c--c
and repeat the measurement between c--c. Add these
figures together for total clearance.
To determine correct clearances for a unit originally
timed for rotation in one direction only, return the
impellers to position 0--0. Divide the total clearance fig-
ure into three parts. Two parts (2/3) will be the
clearance setting between points 0--0 and the re-
FIGURE 12 -- IMPELLER LOBE CLEARANCES