Pumping Machinery Consulting and Training



Con Edison Power Plant - 56" Suction Bell Major Repair of

Flowserve 42APM Vertical Turbine Pump, Cooling Water Application


Problem: Severe cavitation of the suction bell made of Ni-Resist Cast Iron. Bell and impeller casing were a single-piece design, thus requiring replacement of the entire expensive part


Solution by a thorough joint effort between Con Edison and Pumping Machinery, LLC: separate design into a 2-piece flanged construction. Replaced upper part was made entirely from stainless steel. The bottom part received stainless steel flange. Two parts were then bolted together, creating a much more reliable, long-lasting part, with superior cavitation resistance


Turn-around time: (4) weeks


APM style design - reliability improvement  is the key: cavitation damage solutions

Suction bell and impeller casing was a single integral piece - a major original design oversight

When impeller casing got damaged by cavitation - the entire piece is a problem

Cavitation damage was intense

Upper portion was cut off

Bell portion prepped to receive new stainless steel flange. Upper portion (casing) will become entirely stainless steel, to bolt to the modified bell

Measurements are critical, since the final part must be directly retrofitted in place of the old

Watch the Video of Bell Pre-Machining


Brand new upper stainless part (cone for the impeller) is being machined...

...and it is coming about nicely...

...lower bell is ready to receive new flange...

...flange for the bell is ready for it.


Old Design

New Improved Design

On the way to a customer - with more pump solutions to come