Page 173 - Steam Turbines Design, Applications, and Rerating

152 Chapter Eight

(a)

(b)
Figure 8.9 The steam extraction principle: Turbine speed changes; extraction steam
demand is constant (a). Extraction steam demand reduces; turbine speed is constant (b).
(Elliott Company, Jeannette, Pa.)

power. The vertical coordinate represents the total steam flow through
the turbine inlet, the sum of exhaust and extraction flows, and the hor-
izontal coordinate shows the total horsepower developed. The zero
extraction line represents the steam flows required for various loads
when extraction flow is zero. The total extraction line represents the
steam flow required when exhaust flow is zero (except for cooling