Turbine Classification

Turbines as fundamentally classified as “Impulse” or “Reaction” type by how the steam
expands through a nozzle and impact a blade. Impulse Stages are often compared with
waterwheels, reaction stages to a rotary lawn sprinkler. There are different ways to classifythe turbine based on:

A. By the action of steam:
a. Impulse
b. Reaction
c. Impulse and reaction combined
B. By the number of step reductions involved:
a. Single stage
b. Multi-stage
c. Whether there is one or more revolving vanes separated by stationary reversing vanes.
C. By the direction of steam flow:
a. Axial
b. Radial
c. Mixed
d. Tangential
e. Helical
f. Reentry
D. By the inlet steam pressure:
a. High Pressure
b. Medium pressure
c. Low pressure
E. By the final pressure
a. Condensing
b. Non-condensing
F. By the source of steam:
a. Extraction
b. Accumulator