Saturated steam is, in contrast to superheated steam, steam that is in equilibrium with heated water at the same pressure, i.e., it has not been heated past the boiling point for that pressure.
If saturated steam is reduced in temperature (whilst retaining its pressure) it will condense to produce water droplets, even if it is still considerably above the boiling point of 100 °C at standard pressure. These condensation droplets are a cause of damage to steam turbine blades, the reason why such turbines rely on a supply of dry, superheated steam.
Dry steam is saturated steam that has been very slightly superheated. This is not sufficient to change its energy appreciably, but is a sufficient rise in temperature to avoid condensation problems, given the average loss in temperature across the steam supply circuit. Towards the end of the 19th century, when superheating was still a less-than-certain technology, such steam-drying gave the condensation-avoiding benefits of superheating without requiring the sophisticated boiler or lubrication techniques of full superheating.
Read more about this topic: Superheated Steam
Famous quotes containing the words saturated and/or steam:
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—Ralph Waldo Emerson (1803–1882)
“A steam ran small and terrible and shrill;
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—Hilda Doolittle (1886–1961)