Flowserve PolyChem GRP - Manual (Page 34)

USER INSTRUCTIONS POLYCHEM GRP ENGLISH 71569132 12-04A
Page 34 of 52
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6.7 Setting impeller clearance
A new impeller gasket [4590] must be installed
whenever the impeller has been removed from the
shaft. (Impeller clearance settings are in section 5.3.)
6.7.1 Initial clearance setting for PolyChem GRP
pumps
Install the impeller [2200] by screwing it onto the shaft
until it firmly seats against the shaft shoulder.
The impeller could have sharp edges
which could cause an injury. It is very important to
wear heavy gloves.
Tighten the impeller with the impeller wrench from the
Flowserve Mark 3 tool kit. To do this, grasp the
impeller in both hands and, with the impeller wrench
handle to the left (viewed from the impeller end of the
shaft) spin the impeller forcefully in a clockwise
direction to impact the impeller wrench handle on the
work surface to the right. (See figure 6-3.)
Do not attempt to tighten the impeller
on the shaft by hitting the impeller with a hammer or
any other object or by inserting a pry bar between the
impeller vanes. Serious damage to the impeller may
result from such actions.
Figure 6-3
Now set the initial impeller clearance by loosening the
set screws [6570.3] and rotating the bearing carrier
[3240] to obtain the proper clearance. Turn the bearing
carrier counter-clockwise to move the impeller towards
the rear cover and clockwise to move it away. Use a
scale, caliper, or depth gage to measure from the rear
cover to the impeller as shown in figure 5-12. Refer to
the charted values in figure 5-13 for the proper initial
impeller clearance as shown in figure 5-12. Rotating
the bearing carrier the width of one of the indicator
patterns cast into the bearing carrier moves the impeller
axially 0.1 mm (0.004 in.). (See figure 6-5.)
Tightening the set screws [6570.3] will cause the
impeller to move 0.05 mm (0.002 in.) closer to the
rear cover because of the internal looseness in the
bearing carrier threads. This must be considered
when setting the impeller clearance.
Figure 6-5
Lastly, uniformly tighten the set screws
[6570.3] in incremental steps up to the final torque
value to lock the bearing carrier in place.
Figure 6-6
Example: First, measure the initial distance “X” as
shown in figure 5-12. To determine the number of
indicator patterns that you will need to rotate the carrier,
divide 0.10 (for mm or 0.004 for in.) into the desired
setting. Flowserve suggests that a felt tip pen be used
to mark an initial reference point on the bearing housing
and the bearing carrier as shown in figure 6-6.
Then make a second mark on the bearing carrier the
required number of indicator patterns from the initial
reference point. Rotate the bearing carrier until the
second mark on the bearing carrier lines up with the
initial reference point mark on the bearing housing.
Tighten the set screws [6570.3] in incremental steps
to lock the bearing carrier in place. The impeller is
now set relatively close to its final location. The seal
can now be set.
6.7.2 Final clearance setting
Like all front vane semi-open style impellers, the final
PGRP open impeller clearance must be set off the
casing. The casing must be installed to accurately
set the impeller clearance.
Attach the power end/rear cover/impeller assembly to
the casing. Now set the impeller clearance by
loosening the set screws [6570.3] and rotating the
bearing carrier [3240] to obtain the proper clearance.
Turn the bearing carrier clockwise until the impeller
comes into light rubbing contact with the casing.
Rotating the shaft at the same time will accurately
determine this zero setting.
FIGURE 6-5
Rotation equivalent to 0.1 mm
(0.004 in) axial movement
Indicator
pattern