SPP Pumps Instream - Manual (Page 9)

Operators Instructions for
Instream Centrifugal Pumps
Manual No/Rev
W23-001E / 8
Our policy is one of continuous improvement and we reserve the right to alter specifications at any time
Page 9 of 16
Where new joints are made, correct gasket
thicknesses must be maintained.
After reassembly the rotor must turn easily by
hand, otherwise premature pump failure may
occur.
6.3.2 Dismantling
Introduction
In general when pumps are dismantled,
inspected and/or replacement parts fitted, the
work is undertaken for one of the following
reasons.
a) Preventative Maintenance:
Because the time for the regular periodic
inspection
has become due. Planned
inspection and maintenance at pre-determined
intervals is a sound insurance against a forced
shutdown due to a failure at a more
inconvenient time.
b) Remedial Maintenance:
Perceptible fall off in pump performance
affecting capacity and pressure or: failure of
mechanical seal or: excessive and continuous
vibration with persistent noisy operation.
The extent of dismantling required will depend
upon the reasons above.
In the case of preventative maintenance,
inspections are done at preselected times and
the
pump usually requires complete
dismantling, so that all parts can be cleaned,
examined and measured for wear.
The extent of dismantling for remedial
maintenance will depend upon the cause of
failure and needs only to reveal the source of
the trouble.
When dismantling the pump, the volute casing
can remain mounted in the pipework. Tightly
shut both the inlet (if fitted) and outlet valves
and
disconnect any external service
connectors.
On pumps using motors with frame sizes up to
and including D180M, it is NOT advisable to
remove the stub shaft under normal pump
maintenance conditions. On these pumps, the
stub shaft (21.11) is attached to the motor
using
a collet nut and grub screw
arrangement. It requires special tools and
fixtures to remove and reassemble correctly. It
is recommended that this be performed only
by a trained SPP Pumps Ltd. Service
Engineer or an authorised SPP Pumps Ltd.
dealer/agent.
To dismantle pump, proceed in the following
sequence:
1.
Drain liquid from the casing, remove plug
(90.31).
2.
Unscrew nuts (92.0) on volute casing studs
(90.2)
3.
Motor (80.1), complete with supporting frame
(34.4) and casing cover (16.1), can now lifted
clear of volute casing (10.2).
Note! On the pumps fitted with a clamped casing
cover, care must be taken not to disturb the
joint between the casing cover (16.1) and
supporting frame (34.4).
4.
Lay the pump down horizontally taking care
not to damage the impeller.
5.
The impeller (23.0) is now clear of casing
(10.2) and can be removed by unscrewing the
impeller nut (92.2) in a counter clockwise
direction and removing the lockwasher (93.0).
6.
Remove the impeller key.
7.
With the impeller (23.0) and key (94.01)
removed, the shaft sleeve (52.3) complete
with the rotating element of the mechanical
seal (43.3) can now be slid off shaft (21.11).
8.
The seal should be carefully examined and if
worn, should be replaced. Do not remove the
rubber or elastomer bellows from the sleeve,
unless necessary for examination or cleaning.
9.
To remove the stationary element of the
mechanical seal:
a)
For pumps fitted with bolted casing cover,
remove stud nuts (92.02) from casing cover
studs (90.22).
b)
For pumps, fitted with a clamped casing cover,
and to continue dismantling pumps fitted with
bolted casing covers:
Remove the casing cover (16.1), complete
with the stationary element of mechanical seal
(43.3) from the supporting frame (34.4) by
carefully prising apart with screwdrivers or
similar tools which fit in recess between the
casing cover (16.1) and the supporting frame
(34.4).
Care must be taken to ensure that the casing
cover (16.1) does not damage the shaft (21.1).
6.3.3 During and After Dismantling
1. All parts must be carefully cleared and tested
for wear. Recondition or replace parts where
necessary.