Sales & Marketing Alignment: How to Synergize for Success
Nevada power condensate pump
1. Tough Composite Pump Bearings
Prove Their Value at Power Plant
Retrofitting DuPont™
Vespel®
CR-6100 for line-shaft bushings and wear rings
in condensate pumps at Nevada Power sharply reduces vibration, protects
shaft against damage.
When a large four-stage condensate pump failed in August 2006,
DuPont was enlisted to help Nevada Power replace worn line shaft
bushings of carbon graphite with Vespel®
CR-6100 parts without re-
placing the throat bushing. Vibration immediately dropped essentially
to zero. In April 2007, a faulty impeller caused the pump to fail again. It
was discovered that the brittle carbon graphite throat bushing was de-
stroyed, but the tough Vespel®
CR-6100 bushings survived with only
a slight increase in shaft clearance. If they had failed, severe damage
to the pump may have occurred, with repair costs estimated at more
than $50,000.
Based on this experience and on sharply reduced vibration, DuPont
helped Nevada Power’s maintenance team replace carbon graphite
line-shaft bushings, wear rings and the throat bushing with Vespel®
CR-6100 in three additional pumps that deliver condensate to boiler
feed pumps.
The pumps are 700 hp (522 kW) Ingersoll Rand 27APKD-4 four-
stage, deep-well units fed by a wet well. The process fluid is water
condensate at 110 to 120°F (43 to 49°C).
Benefits Gained
Reduced vibration. Relying on both the outstanding anti-seizing,
anti-galling performance and the precise machinability of Vespel®
CR-6100, the maintenance team installed bushings and wear rings
made to tight clearance, a key factor in reducing vibration (chart at
left). Bushing clearance was just 0.008 in (0.2 mm). The wear rings,
which have an ID of 9.375 in (238 mm), have clearance of 0.012 in
(0.3 mm). Vibration and accompanying wear and tear on pump seals
and bearings remain low over time thanks to the low friction and high
wear resistance of Vespel®
CR-6100.
Increased reliability. The tight wear ring clearance allowed by Vespel®
CR-6100 reduces NPSHR (net positive suction head required). This
reduces the risk of cavitation and improves reliability.
Damage protection. The toughness of Vespel®
CR-6100 helps pre-
vent damage to the shaft and other pump components in the event of
impeller failure or other process upsets.
End User
Nevada Power Company
Charles Lenzie Generating Station
Las Vegas, Nevada USA
For more information, visit
pumps.vespel.dupont.com