Teikoku USA | Chempump
Instruction Manual G-Series
21
4. Maintenance
4.1 Recommended Tools for Disassembly,
Reassembly, and Inspection
Table 4-1 Recommended Tools
Size
Description
Dial Indicator
Dial Indicator (.200 travel) for determining
end play
Verniers
Telescopic gauges
5/16"-3"
4.2 Periodic Inspection
The TRG meter should be checked periodically during operation. If
the initial reading (TRG) was not recorded, then the color coding
system discussed in
Table 2-1
may be used to determine bearing
changing intervals.
4.2.1 Bearings
Since the bearings in this pump are lubricated by the process fluid,
it is essential that bearing inspection and replacement periods be
based on experience in each particular installation. Bearing life
will depend, to some extent, on variable factors including lubrica-
tion quality, temperature, number of starts and stops, viscosity,
and suspension content of the fluid being pumped, as well as am-
bient temperature and atmospheric conditions of the operational
area. Each time one of these factors is changed, compensation
must be applied in bearing inspection periods.
As noted above, the TRG meter should be checked periodically
during operation. If the initial reading (TRG) was not recorded,
then the color-coding system in
Table 2-1
may be used to deter-
mine bearing changing intervals. This inspection is necessary to
determine the rate of bearing wear, thereby enabling setup of a
proper inspection and replacement schedule. See
Table 4-2
for
the maximum wear allowable.
If the inspection indicates that bearings are not wearing or are
wearing very slightly, the next inspection may be put off for an
additional 1,500 running hours, or three months of operation,
whichever occurs first. If inspection indicates only slight wear, the
interval may be lengthened.
If bearings must be changed at the initial inspection, they will
need to be changed again in the time period which necessitated a
change at the initial inspection, i.e., 1,500 running hours.
Frequency of periodic bearing inspection can best be determined
by experience, and from these inspections, the time for replace-
ment can best be indicated.
Bearings can be inspected and replaced without removing the
pump casing from the line. No main piping connections need to
be broken. Refer to
4.5.3
, Disassembly and Reassembly, starting
on
page 23
.
In the event the TRG bearing wear monitor indicates bearing wear
on the wear indicator:
1. Measure the inside diameters of the front and rear bearings
and compare to the diameter of the rotor shaft journal. If the
difference in diameters is greater than that indicated in
Table
4-2
, replace the bearings.
2. Inspect the thrust faces of the front and rear bearings. If any
scoring wear is visualized, measure the length of the bearings.
Replace the bearing if the measured length is less than that
indicated in
Table 4-2
.
3. Examine the bearings for any grooving or scoring, particu-
larly on the inside diameter and thrust faces. The existence of
grooving or scoring indicates the presence of solids or foreign
matter in the system which should be eliminated prior to be-
ginning operation again.
4.2.2 Rotor Assembly Inspection
The complete rotor assembly should be visually inspected for
cracks, breaks, pitting, or corrosion which might destroy the ef-
fectiveness of the hermetically sealed rotor end covers and sleeve.
The rotor assembly shaft should also be visually inspected at the
bearing contact area for general appearance and uniform wear.
Excessive undercutting, pitting, or scoring is cause for rotor re-
placement. Minimum allowable shaft diameter is noted in
Table
4-2
.
4.2.3 Automatic Thrust Balance and End Play
Inspection
The provision of automatic thrust balance design in the G-Series
pump, with it close running seal faces and wearing rings to insure
proper balance chamber pressures, requires that a close visual in-
spection be made of the impeller, front bearing housing, front
bearing and front rotor end cover at the time bearing inspection
is made.
During disassembly for bearing inspection, measure the unit end
play as follows:
1. For all models, after removing the rear bearing housing from
the unit and with all other parts in place, measure the total
axial (front to back) movement of the shaft, or,
2. In the case of Models GA, GB, GC and GVBS or pumps
equipped with thrust surfaces after the unit has been sepa-
rated from the pump casing, measure the total axial (front to
back) movement of the impeller assembly.
If the measured end play exceeds end play (new) noted in
Table
4-3
or
4-4
, then remove the impeller from the shaft and the bear-
ings from within the rotor chamber. Visually examine the impeller
seal faces, front bearing housing seal face, and the front rotor end
cover for noticeable wear; also measure the length of the front
bearing, See
Table 4-2
. (The rear bearing, because of its position,
will not usually experience axial wear). Should the front bearing
length be below the unit of when new dimension, replace with a
