PURPOSE: To prevent the deposition and sticking of scale in a turbine by removing scale material from steam before admitting the steam into the turbine.

CONSTITUTION: Only the steam is removed from the fluid gushing out of a steam well 1 with a steam well separator 2, and is introduced into a nozzle 3 to increase the velocity of the steam. Since part of the steam is condensed to drain and the scale in the steam is concentrated in the drain, the drain is removed with a mist separator 4, by which the scale is also removed together with the drain 5. The steam removed of the scale is thereafter fed to a pressure restorer 6 to restore the pressure energy and is admitted through a main steam stop valve 7 and a regulating valve 8 into a turbine 9. As a result, the scale material in the steam can be removed on the outside of the turbine; therefore, the inside of the turbine is kept free from deposition and sticking of the scale.