Evolution of the Steam Turbine- Classification and Types
The first steam turbine, at its time indeed did spark off the industrial revolution through out the west. However, the turbine at that time was still an inefficient piece of heavy weighing high maintenance machine. The power to weight ratio of the first reciprocating steam turbine was extremely low, and this led to a great focus improving the design, efficiency and usability of the basic steam turbine, the result of which are the power horses that currently produce more than 80% of today’s electricity at power plants!
How are Steam Turbines Classified?
Steam Turbines can be classified on the basis of a number of factors. Some of the important methods of steam turbine classification are enunciated below:
On the basis of Stage Design:
Steam turbines use different stages to achieve their ultimate power conversion goal. Depending on the stages used by a particular turbine, it is classified as Impulse Turbine, or Reaction type.
On the Basis of the Arrangement of its Main Shaft:
Depending on the shaft arrangement of the steam turbine, they may be classified as Single housing (casing), tandem compound (two or more housings, with shafts that are coupled in line with each other) and Cross compound turbines (the shafts here are not in line).
On the Basis of Supply of Steam and Steam Exhaust Condition:
They may be classified as Condensing, Non Condensing, Controlled or Automatic extraction type, Reheat (the steam is bypassed at an intermediate level, reheated and sent again) and Mixed pressure steam turbines (they have more than one source of steam at different pressures).
On the basis of Direction of Steam Flow:
They may be axial, radial or tangential flow steam turbines.
On the Basis of Steam Supply:
Superheated steam turbine or saturated steam turbine.
