Goulds Pumps 3500XD - IOM - Manual (Page 34)

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3500XD IOM 8/07
IMPELLER CLEARANCE ADJUSTMENT
s
! WARNING
Lock out driver power to prevent accidental start-up and
physical injury.
s
! WARNING
Before installation or disassembly of the coupling guard
is performed, the driver must be de-energized, the driver
controller/starter put in a locked out position and a
caution tag placed at the controller/starter indicating the
disconnect. Replace coupling guard before resuming
normal operation of the pump or serious physical injury
may occur. Goulds Pumps, Inc. assumes no liability for
avoiding the practice.
l
! CAUTION
The impeller clearance setting procedure must be
followed. Improperly setting the clearance can result in
equipment damage and heat generation casing failure.
If a gradual loss of head and/or capacity occurs, performance
can be restored by adjusting the impeller. If performance
cannot be restored by adjusting the impeller, the pump should
be disassembled and the impeller, suction sideplate, and
casing inspected for wear.
The proper impeller clearance setting provides for equal
clearance on both the front side (impeller to suction
sideplate) and the back side (repeller to stuffing box cover).
Prior to setting the impeller clearance, it is first necessary to
measure the total impeller travel (normally in the range of
0.090” to 0.140”). Half of the total travel value then
becomes the proper clearance to set the impeller off the
suction sideplate.
IMPORTANT: If pump is equipped with a cartridge
mechanical seal, the centering tabs must be in place and
tightened, and the set screw collar loosened. Failure to
take these steps prior to adjusting the impeller clearance
can damage the mechanical seal.
To adjust clearance, proceed as follows (Fig. 18):
1. Shut down pump.
2. Lock out power to driver.
3. Remove coupling guard and coupling spacer.
4. Loosen adjustment bolts and nuts (D).
5. Tighten each bolt (C) evenly while slowly rotating shaft,
until impeller just starts to rub against suction sideplate.
6. Clamp a dial indicator to the power frame, with the
button resting on the end of the shaft or against the face
of the coupling hub. Set indicator at 0.
7. Loosen bolts (C).
8. Be sure jam nuts on bolts (D) are loose. Tighten bolts
(D) evenly while slowly rotating shaft, until
impeller/repeller just starts to rub on the stuffing box
cover.
9. The dial indicator will now show the total travel of the
impeller. Divide the total travel by two to determine the
proper front and back clearance; i.e. if total travel is
0.120”, set clearance at 0.060”.
10. Loosen bolts (D).
11. Tighten bolts (C) evenly until dial indicator reads the
proper clearance (½ the total travel).
12. Tighten bolts (D) evenly. Check to make sure all bolts
(C) are tight. Finally, tighten jam nuts on bolts (D).
The impeller is now set with equal clearance on the front and
back sides. Rotate shaft several times to check for free
turning.
IMPORTANT: For pumps equipped with cartridge
seals, the following steps must be taken after impeller
adjustment to properly set the seal prior to start-up.
1. Tighten drive collar set screws.
2. Loosen and back off centering tabs.
s
! WARNING
Pump shall never be operated without coupling guard
installed correctly.
Fig. 18