Page 43 - Steam Turbines--Design, Applications, and Rerating by Heinz-Bloch, Murari-Singh

24 Chapter One

Figure 1.18 A separate base is provided for this turbine mod-
ule. (General Electric Company, Fitchburg, Mass.)

cations. These applications span an extremely wide range of turbine
design parameters, such as inlet steam conditions, extraction and
exhaust conditions, and turbine speeds. The wider energy range and
widely differing applications have always complicated the normal
design process. This design process involves many interactions among
mechanical, thermodynamic, and application factors to achieve a truly
optimum design.
To manage this process, many manufacturers depend on the building
block principle. The major components of the turbine are designed with
a well-planned structure. Figure 1.20 shows the higher-level division of
the turbine. The front standard, for example, consists of a family of
standard components of increasing size as bearing loads increase.
Other major families of components include inlet and extraction valve
gears, high-pressure casings, exhaust casings, and bearing assemblies.
Each of these components has well-established application ranges, and
operating experience can be readily identified. From these families of
components, the engineer can select the optimum components to inte-