Flowserve VTP Wet Pit - Manual (Page 53)

VERTICAL TURBINE PUMPS (VTPS) CENTRIFUGAL PUMPS ENGLISH 71569224 – 10-13
Page 53 of 76 flowserve.com
When attempting to rework any part,
extreme care must be taken to maintain alignment of
mating parts and ensure “as new” tolerances.
The inspection, disassembly of bowl assembly
requires expertise and tools to perform the job
correctly. It is recommended to seek the services of
Flowserve trained technicians to inspect and repair
bowl assemblies.
Inspection of enclosed impellers 6.9.3.1
a) Clear all passageways and check for signs of
damage from abrasion or corrosion. Replace an
impeller that shows signs of excessive wear.
b) Check impeller running clearances against “as
new” tolerances listed in the section 0. If the
clearances exceed the maximum tolerances
shown by more than 50%, the new wear rings
should be installed to obtain correct tolerances.
c) If the original unit was furnished with bowl and
impeller wear rings, they may be pressed or
machined off.
Please note that certain repairs may require special
skills and it is recommended to contact Flowserve
authorized service center before attempting any such
repairs.
See wear ring tolerance chart in section 0.
Inspection of semi-open impellers 6.9.3.2
a) Clear all passageways and check for signs of
damage from abrasion or corrosion.
b) Replace any impeller, which shows signs of
excessive wear. If the bowl faces or impellers
are worn slightly (grooves in either impeller or
bowl under 0.79 mm (1/32 in.)), they can be
corrected by re-facing the impeller and bowl.
0.79 mm (1/32 in.) is the maximum that can be
machined off without harm to the hydraulic
performance of the pump.
c) The machining must match the face angle and
should be re-faced by an authorized Flowserve
repair facility or replaced.
If the impeller has a balance ring on the topside
(side opposite pumping vanes) running clearances
must be checked.
Please see section 6.9.4 for wearing ring tolerance
chart for enclosed impellers.