Rare Radial Steam
Precision reverse engineering
resolves vibration issues
BY ROD WHITTAKER
OVERHAULING A STEAM TURBINE as part of a planned
maintenance schedule is a regular task for many large-scale industrial enterprises that depend on these units to generate electrical power. However, for one pulp manufacturing plant in
Eastern Canada, the refurbishment of its 25 MW Stal Laval radial
steam turbine would need expert engineering to resolve the vibration issue – the first time this repair has been completed in
North America and it would be successfully delivered by
Industrial processes that have high power consumption often
use on-site power generation to provide a cost effective power
supply, but this entails also providing the necessary levels of
maintenance support to keep the turbine operational. In many
cases, this will be provided by a specialist service engineering
company that has the necessary facilities and expertise to deliver
timely repairs and maintenance.
MINIMIZING REPAIR TIMES
Steam turbines are used around the world to generate power,
but the vast majority are of the axial flow design. In situations
where radial flow designed units need to be repaired, they are
usually shipped to Europe, where they are more accustomed
to this design. However, this increases the total repair time,
which is a crucial factor when the entire manufacturing process
relies on this power source.
Manufactured in the 1970s, the 25 MW Stal Laval radial turbine
uses steam that enters along the center-line of machine and
expands outwards through two contra-rotating rotors until it
reaches the exhaust pipework on the periphery of the turbine.
The two rotors, left hand (LH) and right hand (RH) are made
up of nine and eight stages respectively and are each coupled to
Although more common in Europe, radial turbines are also
used in marine applications due to their relatively compact dimensions, compared to an axial turbine with a similar power
output. Their design means that they are limited to a maximum
output of approximately 30 MW, making them more suitable
to small industrial generating sets rather than power generation
for the grid.
The radial steam turbine powered a
Canadian pulp manufacturing plant.
Photo courtesy: Sulzer
Rod Whittaker is project Manager at
Sulzer’s Edmonton Service Center.