Xylem LSNIH - Manual (Page 20)

Installation, Operating and Maintenance Instruction Model LSN
LSN 100-english page 18 Revision 01
Article No 771076024 Issue 01/2010
In most cases it make sense, if damaged absolutely
necessary, to renew the mechanical seal and the
bearings.
Deposits on the impeller (230), in the volute casing
(102V) or on the casing cover must be removed.
8.7.1 Clearance at impeller
Suction side of impeller Back vanes of impeller
Drive side of impeller
Only for pump sizes
100-65-315
125-80-315
125-80-400
125-100-315
125-100-400
150-125-315
150-125-400
200-150-315
200-150-400
Nominal diameter D (mm)
60
68
85
100
120
135
155
175
220
Radial
clearance s
(mm)
new
min. 0,15 0,17 0,20 0,22 0,25
max. 0,19 0,22 0,24 0,27 0,30
wear limits 0,78 0,85 0,90 1,05 1,15
Axial
clearance a
(mm) new 0,8 - 1,2
wear limits max. 1,7
When the wear limits has been reached or
exceeded, the worn parts must be replaced.
For volute casings (102V) with a wear ring (502.11)
and cover casings (161) with a wear ring (502.31)
there are the following possibilities to restore the
correct clearance:
a) Renew impeller (230) and wear ring. Then the
original measures are restored.
b) A customized wear ring (bored to fit) can be
supplied to avoid replacement of the impeller.
Please contact factory for details.
When volute casing (102V) or casing cover (161)
without wear ring must be repaired, a wear ring can be
installed to renew pump performance. Remachining of
the volute casing and /or casing cover is required.
Please contact the factory for details and assistance.
8.8 Mounting
Re-assemble the pumps using the reverse order of
steps as completed for pump disassembly. However
the following observations should be considered:
Pay attention to the utmost cleanliness when
reassembling the pump.
For tight tolerances, e.g. between shaft sleeve
(433) and shaft (210) or impeller (230) and shaft
(210), as well as thread, use a suitable anti-galling
compound (e.g. Molykote/Never-Seeze), so that
the assembly and the next disassembly will be
easier.
Anti-galling compound must be compatible with
the pumpage.
Screws should be tightened, with the following
torque:
Location
Screw
Size
Screw torque in Nm
Lubricated
threads
Dry threads
Casing screws
M12 35 50
M16 105 150
M20 210 305
All other screws
M10 35 50
M12 60 90
M16 150 220
Before mounting the second bearing on the shaft
push in the circlip (932.51) between the two
bearings.
Before mounting new bearings, warm them up to
80°C in an oil bath or using a bearing heater. If
necessary use a tube to force the inner ring onto
the shaft by gentle taps with a hammer. Hold the
outer ring to avoid vibrations of the balls.
When bolting together the bearing bracket (330)
with the bearing bracket lantern (344) and the
bearing bracket lantern with the volute casing
(102V), screws should be positioned in the centre
of the drilled holes. Failure to do so could result in
improper oil setting.
Push the flinger (507) onto the shaft (210) till it
rests axially against the shoulder of the shaft.
Between flinger (507) and Bearing bracket lantern
(344) there must remain a clearance of at least
0,7 mm.
If necessary you can use a driver for mounting
(see picture 14).
pic 14
Do not use excessive force.
For mounting of the shaft sealing (packing or
mechanical sealing) see separate description
"Mounting Instruction of Shaft Sealing" and
chapter 8.5.
For impellers with back vanes the axial clearance
between the back vanes and the casing cover