Goulds Pumps JC - IOM - Manual (Page 33)

APPENDIX
SPECIAL INSTRUCTIONS
A) KAOLIN SERVICE -KJC PUMPS
OPTIMUM IMPELLER RUNNING
CLEARANCE
The optimum impeller running clearance is the minimum
clearance that will not significantly increase the input
horsepower from the shear rate induced drag at the suction
disc liner. For most liquids or slurries, the optimum
performance of the JC pump is achieved with the impeller
almost rubbing against the suction disc. Increasing this
clearance causes more internal leakage around the impeller
vanes, which results in decreased performance.
When pumping kaolin clay, the decrease in pump head
from the internal leakage can be more than offset by the
decrease in horsepower such that the overall performance is
increased. The optimum clearance is set by adjusting the
pump, when it is running, using a discharge pressure gauge
and ammeter to monitor the results.
During an adjustment to reduce the clearance, the clearance
has become too small when the percentage increase in
motor amperes exceeds the percentage increase in
discharge pressure. The opposite is true when increasing
the clearance. The adjustment can be made without a
pressure gauge, but it will be less accurate though perhaps
satisfactory for the application.
If the slurry percentage solids varies frequently, it may be
more practical to adjust the clearance for the most difficult
to pump slurry and not change it for the other
concentration.
B) EXPELLER
General
!
Dynamic seals are not allowed in an ATEX
classified environment.
To meet the high demand for waterless sealing of stuffing
boxes in slurry pumps, Ashland Operations/Goulds has
added an expeller to the JC line. Using its basic bearing and
wetted end configuration, the JC now incorporates a hub
disc that has been enlarged to allow for the expeller option.
When operating at normal design conditions, the expeller
reduces the pressure usually present in conventional end
suction pump stuffing boxes to zero (0). Theoretically, the
only need for a packed stuffing box in expeller pumps is to
seal the casing when the unit is shut-down or running at
restricted flows.
s
! WARNING!
IMPORTANT: BEFORE PERFORMING ANY
WORK, INSURE ELECTRICAL SUPPLY IS
LOCKED OUT.
Clearance Adjustment
The impeller clearance in the JC pump with optional
expeller should be maintained at .015² from the face of the
impeller (101) to the suction cover liner (100B). Adjust this
clearance as often as necessary in order to maintain
efficient pump performance.
IMPORTANT: INSURE THAT THE IMPELLER IS
TIGHTENED ON THE SHAFT PRIOR TO
CLEARANCE ADJUSTMENT.
To Disassemble The Liquid End
1. Remove bolts (370E) that fasten the suction cover 182 to
the casing (100). Remove the O-Ring (412F) and the
suction cover liner (100B). A gentle tap about the
circumference of the liner may facilitate removal of the
liner.
2. Remove the impeller (101) by securing it with a
wooden or soft metal block and turn the shaft in the
counter-clockwise direction facing the pump drive end
from the motor. The reverse of this procedure is also
possible. By securing the shaft, strike the impeller in
the counter-clockwise direction using a lead or
composite mallet.
s
! WARNING!
DO NOT APPLY HEAT TO THE IMPELLER.
3. Remove the casing (100), expeller (262) and hub disc
(expeller housing) (184) as one unit by only removing
bolts (370C) that fasten this assembly to the bearing
frame. Leave the packing and seal cage in the stuffing
box to protect the sleeve and carefully slide the whole
unit until it is clear of the shaft.
4. Remove bolts (370J) to expose the expeller for
inspection.
To Assemble The Wetted End
JC IOM 5/08
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