At both sides of drum, they are steam-water separators, which are composed of cylinder, inlet tube, top cap, overflow ring, guide vane at the drum bottom and bottom plate etc.. The cyclone separator is a kind of steam-water separator with good separating effect. The working principle and process are: The mixture of steam-water with higher velocity of flow  tangential enters into the drum and rotate. Under the action of centrifugal force, the water drops are thrown to the drum wall, making the steam and water preliminary separated. The separated water enters into the drum water volume through the guide vane around the cylinder. The saturated steam in the cylinder flows upward and enters into the clearance of corrugated plates of the hood to flow zigzag. Under the effect of centrifugal force and inertia force, the small water drops are thrown to the corrugated plate. Under the effect of adhesive force, the water film forms and flows downward, the flows into the drum water through the drum wall, making further separation of steam and water, and the saturated steam is introduced into the steam space of the drum from top of the hood or around the hood.