Overhaul Maintenance - Wilo -SCP Einbau- Und Betriebsanleitung

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9.2 Overhaul maintenance

9.2.1 General information
After a long period of service, wear will occur in
parts of the pump, necessitating the renewal of a
few components. Logbook records will indicate
wear as gradual deterioration of performance is
noticed. Once this is known, pumps should be
taken for overhaul. It is recommended that yearly
stripping & checking of wear & tear and clearances
should be done and overhauling where required.
If related pair of components show a marked
degree of wear in relation to the rest of the unit,
then it may be sufficient to renew only the heavily
worn components. If the wear is uniform throug-
hout the pump, then all wearable components
may require renewal.
Measurements should be taken and recorded of all
wearable components at the first, and every sub-
sequent overhaul period. Reference to these
records will enable an accurate assessment of the
rate of wear to be made, and a reasonably accurate
forecast regarding when a particular component
may require renewal can be made.
Internal nominal
diameter of the wear
ring in (mm)
65
100
150
200
250
300
350
Tightening torques – Untreated Screw (black finish); Coefficient of Friction 0.14
Property Torque Nominal diameter – Coarse thread
class
M6
8.8 Nm 9.2
Ft. lb 6.8
64
Nominal gap at the
diameter in (mm)
0.38
0.46
0.58 - 0.55
0.62
0.68
0.74
0.84 - 0.80
M8 M10 M12 M14
22 44 76 122
16.2 32.5 56 90
NOTE:
The figures given in the table above are only valid
if the wear rings and the impeller are made with in
the same materials of low galling tendencies. For
materials with higher galling tendencies (AISI 304/
316 etc...), higher clearance is provided (0.125 mm
to be added to given values).
Information regarding original design dimensions
and clearances is furnished in data sheet. Any
other information, if needed, can be requested
from Service Department, WILO SE. Such request
must quote name plate number and type of the
pump in question.
The parts most likely to be affected are:
• Impeller
• Mechanical seal
• Neck Rings
• Sleeves
• Stuffing Box Bush
• Bearings
• Coupling Bushes/ membrane set
Before commencing dismantling operations,
ensure that the following tools and tackles are
available:
• A crane / chain pulley block suitable for handling
the weight of pumping unit.
• A selection of ring and open-ended spanners in
British and Metric sizes.
• Eyebolts in British and Metric sizes.
• Cotton rope, wire rope and slings.
• Hardwood and metal packing blocks.
• Miscellaneous tools including a set of Allen keys,
drills, pin drivers, files etc.
• Extractor / puller for bearing and coupling.
The torque value to be set for a particular size of
screw is dependent upon:
• Material of screw
• Parent metal
• Whether the screw is untreated or plated
• Whether the screw is dry or lubricated
• The depth of the thread
M16 M20 M22 M24
190 300 350 500
140 221 258 369
M27 M30 M33 M36
600 1450 1970 2530
443 1069 1452 1865
WILO SE 10/2019