Page 15 - Steam Turbines--Design, Applications, and Rerating by Heinz-Bloch, Murari-Singh

xiv Preface

increase in power output per ton of steam consumed (although purists
will find this to be the layman’s definition). Making this equipment
without compromising quality, efficiency, and reliability is not easy,
and only the industrial world’s best manufacturers measure up to the
task. It is equally important that a contemplative, informed, and dis-
cerning equipment purchaser or equipment user can be expected to
spot the right combination of two desirable and seemingly contradic-
tory requirements: low cost and high quality.
The starting point of machinery selection is machinery know-how.
From know-how, one can progress to type selection, such as condensing
versus extraction versus backpressure turbine, or reaction steam tur-
bine versus impulse steam turbine. Type selection in turn leads to com-
ponent selection, such as fixed land thrust bearing versus tilting-pad
thrust bearing. These could be exceedingly important considerations,
since both type selection and component selection have a lasting
impact on the maintainability, serviceability, availability, and reliabil-
ity of steam turbines. As a result of these considerations, the ultimate
effect will be plant profitability or possibly even plant survival.
This second edition text is intended to provide the kind of guidance
that will enable the reader to make intelligent choices. We have added
Chapter 16 on the upgrading of steam turbines, completely revised the
chapter on bearings, and added new information on bearing protector
seals, brush seals, oil mist lubrication, and wavy face mechanical seals
that promise to replace carbon ring seals in small steam turbines.
While the text cannot claim to be all-encompassing and complete in
every detail, it was the coauthors’ hope to make the material both read-
able and relevant. We believe we have succeeded in making the text up-
to-date, with practical, field-proven component configuration and the
execution of mechanical drive steam turbines discussed at length. The
emphasis was to be on the technology of the principal machine, but we
did not want to overlook auxiliaries such as fixed-ratio gear transmis-
sions, variable-speed transmissions, overrunning clutches, and cou-
plings. With experience showing that machinery downtime events are
often linked to malfunction of the support equipment, we decided to
include governors, lubrication and sealing systems, overspeed trip
devices, and other relevant auxiliaries. All of these are thoroughly
cross-referenced in the index and should be helpful to a wide spectrum
of readers.
While compiling this information from commercially available
industry source materials, we were again impressed by the profusion of
diligent effort that some well-focused companies expended to design
and manufacture more efficient and more reliable turbomachinery.
With much of this source material dispersed among the various sales,
marketing, design, and manufacturing groups, we set out to collect the