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Reaction vs. Impulse Type Steam Turbines 235
Figure 12.14 Inlet section into
nozzle box of a reaction turbine.
(Asea Brown-Boveri, Baden,
Switzerland)
other. This fact was reaffirmed by one of the world’s largest multina-
tional petrochemical companies whose worldwide affiliates have liber-
ally applied both impulse as well as reaction steam turbines. Through
decades of operating experience and collection of applicable failure
statistics, even the blade failure frequencies assembled by others, and
seemingly favoring reaction turbines, were put in question. The bottom
line is simply that thoroughly well-designed steam turbines of either
type will give highly satisfactory long-term service, while construction
shortcuts can weaken either type to the point of yielding unacceptable
performance.
12.9 Deposit Formation and Turbine
Water Washing
Occasions may arise when deposits form on the internal parts of steam
turbines. The accumulation of these deposits may be indicated by a
gradual increase in stage pressures over a period of time with no evi-
dence of vibration, rubbing, or other distress. Such deposits have a
marked detrimental effect on turbine efficiency and capacity. When
deposits cause extensive plugging, thrust bearing failure, wheel rub-
bing, and other serious problems can result.
Deposits are classified as water insoluble and water soluble. The
characteristics of the deposits should be determined by analysis of
