Flowserve HWX Worthington - Manual (Page 28)

HWX USER INSTRUCTIONS ENGLISH - 07/14
Page 28 of 40
Do not attempt to inspect condition
of bearings until they have been cleaned.
c) Solvent for cleaning bearings should be in a
clean container. Place bearings in solvent and let
soak for a short time. Agitate the bearing around
near the top of the container, giving it a turn now
and then until it is clean. Rinse in a clean
container of fresh solvent.
Do not spin dirty bearings. Rotate
them slowly while washing.
d) Dry thoroughly cleaned bearings. If an air hose is
used for drying, make sure it is clean dry air.
Do not allow the bearings to spin by
force of air. Hold the inner and outer rings to
prevent bearing from spinning.
e) Inspect bearings immediately. If there is any
question as to the condition of a bearing do not
hesitate to replace it. There are many conditions
that contribute to the deterioration of the
bearings. A qualified bearing representative
should be consulted if there is any question of
bearing condition.
f) Inspected bearings which will be reused should
be packed with new grease or dipped in clean
lubricating oil, covered with clean lint free rags or
other suitable covering and placed in a clean box
or carton until ready for installation.
Under no circumstances the
bearings are to be left exposed.
6.7.8 Labyrinths or bearing isolators (if fitted)
a) The lubricant, bearings and bearing housing
seals are to be inspected for contamination and
damage. If oil bath lubrication is utilised, these
provide useful information on operating
conditions within the bearing housing.
b) If bearing damage is not due to normal wear and
the lubricant contains adverse contaminants, the
cause should be corrected before the pump is
returned to service.
c) Labyrinth seals and bearing isolators should be
inspected for damage but are normally non-wear
ring parts and can be re-used.
Bearing seals are not totally leak free devices.
Oil from these may cause staining adjacent to the
bearings.
6.8 Assembly
To assemble the pump consult the sectional
drawings.
Ensure threads, gasket and O-ring mating faces are
clean.
6.8.1 Wear rings
The impeller may be fitted with both front and rear
wear rings or front ring only.
The impeller ring(s) are renewable and should be
replaced when badly grooved, and/or when pump
performance does not meet the system requirements.
Whenever it becomes necessary to replace either
wear ring, both rings involved
(impeller and
casing/casing cover) must be ordered and replaced
as a set as they are furnished standard size only.
Spare impeller wear rings are supplied with a material
stock over outside diameter which has to be
machined off after rings fitting on impeller. If an
impeller with its wear rings is ordered as spare, it will
be supplied fully machined, including wear rings
outside diameter, to original dimensions. Casing wear
rings are always supplied fully machined. Be sure to
re-establish the original running clearance between
the two wear rings involved by machining the fitted
impeller ring.
Running clearance is determined by measuring the
inside diameter of the stationary part and the outside
diameter of the rotating part (for example, the inside
diameter of the case wear ring and outside diameter
of the related wear ring ring on the impeller), and
taking their difference to get the running clearance;
that is, the diameter of the stationary part minus the
diameter of the rotating part equals the actual running
clearance.
Measurement should be taken with a micrometer and
each part should be checked for trueness or
roundness by taking diametrical readings 90 degrees
apart. To determine whether the actual running
clearance has increased to a point where
replacement of a part is advisable, compare the
actual clearance with the design clearance that is
given in the cross sectional drawing. Then consider
the wear with respect to mechanical and hydraulic
efficiency and decide whether to restore the design
clearance.
Before final assembly, the trueness and the running
clearance of the following should be checked:
1. Stuffing box bushing [4133].
2. Case wear ring [1500.1], casing cover wear ring
[1500.2], and impeller wear rings [2300.1–
2300.2]; restore running clearance that is given in
cross sectional drawing and roundness as
outlined in section 6.8.1.1 and 6.8.1.2.
6.8.1.1 Impeller wear rings
a) To remove impeller wear rings, mutually remove
wear ring set screws or ground off tack weld.
Rings can be machined off or grind two slots
diametrically opposite across the width of the ring
so it can be split apart. Use caution if ring is
removed by grinding so as not to damage
impeller hubs.