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Facing the bearing nut, turn it clockwise to loosen. Remove lock nut and lock washer from shaft.
t) Remove shaft from vice and press bearings (15 – 14) off shaft with hydraulic press, if available;
otherwise, leave shaft in vice and pull bearings off shaft with a bearing puller. Slide the deflector ring
(23) off of the shaft.
u) If your pump is oil lubricated: The inner bearing housing cover (29.2) should only be removed if
there is evidence of leakage. If the cover is to be removed, remove the cap screws and slide the cover
out of the bearing housing.
23.
EXAMINATION OF PARTS
Used parts must be inspected before assembly to ensure the pump will subsequently run properly.
In particular, fault diagnosis is essential to enhance pump and plant reliability.
To perform a good visual inspection and to obtain the highest degree of cleanliness, which is essential to
the correct fit and balance of all rotating parts, the shaft must be stripped of all parts. The visual
inspection consists of examining the following parts for those conditions that commonly impair pump
operation. Where the corrective action may not be apparent to a journeyman millwright or a more
extensive examination is required, the inspection item is cross-referenced to a detailed procedure.
Unless noted below, all damaged parts should be replaced rather than repaired.
Cleaning Agents
23.1.
When the pump is used in the steam generator feed, the boiler feed, the reactor feed, or other such steam
(or water) circuit, all internal metal parts of the pump including the case should be cleaned with a
nonpetroleum-base cleaning agent such as alcohol or acetone or a steam cleaner that uses steam from
demineralised water. The basic concern should be to insure that the solvent is compatible with the
pumpage. Petroleum-base agents such as dry cleaning solvent and kerosene may be used for cleaning
internal parts when such agent will dissolve in the liquid being pumped without inducing an ill effect.
Petroleum-base agents should be used to clean the bearings and their housings.
Fumes from alcohol, acetone, petroleum solvents and other such chemicals are injurious to health and
may ignite from a spark; make certain that the area where they are used is well ventilated and have a fire
extinguisher handy.
23.1.1. Casing, seal housing and impeller
a) Inspect for erosion, foreign object damage and cracks; erosion and damage must be corrected before
final assembly.
b) Inspect impeller cap nut (20) and impeller (7) for nicks, gouges, galling and rust. c) Inspect impeller
bore for correct fit with shaft (See Section 6.9.2 "Checking Fit Between Impeller Bore and Shaft").
d) Inspect running surfaces of stuffing box bushing (10), shaft (12), case wearing ring (3.1),
casing cover wearing ring (3.2), and impeller wearing rings (8.1–8.2) for nicks, burrs, scratches,
scouring and excessive wear.
Concentric and smooth surfaces are required (See Section 6.9.1 "Wear Rings").
e) Replace as necessary.
23.1.2. Mechanical seal
a) Mechanical seal stationary and rotating faces should be inspected for signs of wear or cracks and
replaced as necessary.
Doc. ISM0076_MANUALE_CN SEAL-MV_ENG_REV04.DOCX
Pag. 37/49
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