Smith: We have not had any failures. We typically try to do overhauls every 10 to 15 years.
And when we pulled those units apart, they
were in pretty good condition. So, it’s been
pretty successful from a longevity standpoint
and also in the reduced maintenance and
upkeep of those.
Barrett: It is recommended to design the
wicket gate bushings with a quad ring seal (in
contrast to an O-ring seal, a quad ring has four
distinctive edges) in order to keep any river
silt from entering the bushing. If the water
quality is poor, the silt can enter the bushing
and sand the material away, in turn wearing
out the bushing quickly.
Drommi: Our experience at EDF is a bit
short to truly answer this question.
Tooktoshina: Desired results have been
achieved to date. Te bushings from the 1982
project were only removed from service last year,
with still some remaining life. However, they
were replaced because the machine was apart.
Freeman: Results have been good.
Bushings selected based on the results of
the Corps laboratory testing have performed
Q: Do you plan to continue
using self-lubricating bearings
in your hydro equipment?
Drommi: Yes. Tat is the way to go, especially
for the reduction of oil quantities and oil spill.
Smith and Freeman: Yes
Barrett: We plan to continue the use
of self-lubricating bearing material on the
Tooktoshina: We continue to specify this
material for wicket gate and wicket gate
linkage applications when replacements
Q: Do you see potential
Tooktoshina: We explore this option for
most of our brass-type bushing replacements,
including operating ring linkages, etc. Most
times, the 10 to 12 week delivery timeframe
does not allow for their use during an overhaul
that requires one to two week delivery. When
wicket gates replacements are planned, that
lead time is acceptable in those cases.
Barrett: We may look at trunnion bearings
on the butterfy head gates, but that is still up
Freeman: We see a potential future application of installing self-lubricating bearings
in oil-flled Kaplan hubs to reduce the forces
required to operate the blades and to help
Drommi: Anything that slides is potentially a target for self-lubricating application
(such as the embedded side sliding surface of
Smith: For expansion and installation of
new units, I think we’ll defnitely be using
them in those applications. As far as existing,
I think we have them where we pretty much
need them now.
Owners of hydroelectric facilities have the
choice to use conventional bearing materials
or integrate the use of self-lubricating bearings at their projects. 2 Te power producers
interveiwed for this article agree there is a
place and continued opportunities for using
self-lubricating bearings within their hydropower facilities. ■
1Medina, V.F. “Evaluation of Environmentally Acceptable
Lubricants for Dams Managed by the U.S. Army Corps of
Engineers,” WQTN-MS-09, U.S. Army Engineer Research
and Development Center, Vicksburg, Miss., 2015.
2Ueda, R., A. Serizawa, and Ferrer de Andrade, A. “
Self-Lubricating Bearings for Water Turbines,” Proceedings of
HydroVision International 2011, Penn Well Corp., Tulsa,
3“Lubricants and Hydraulic Fluids,” Engineer Manual 1110-
2-1424, U.S. Army Corps of Engineers, Washington, D.C.
Gregory B. Poindexter is associate editor of Hydro Review.
Te audio fle at http://bit.ly/2t-
KaHvi contains an excerpt from Hydro
Review’s interview on self-lubricated
bearings with Nathan Smith, engineer
for Denver Water.