Steam valve and steam turbine system

A steam valve, comprising:

• a valve casing having a valve chest, an inlet flow passage having an opening into the valve chest, an outlet flow passage having an opening into the valve chest, and a valve seat surrounding the opening of the outlet flow passage;
• a first valve body housed in the valve chest and capable of making contact with the valve seat in a vertical direction;
• a second valve body housed in the valve chest coaxially with the first valve body and capable of making contact with the valve seat in the vertical direction;
• a second valve rod inserted through an upper section of the valve casing in the vertical direction and extending from the second valve body to an outside of the valve casing;
• a first valve rod inserted through an inside of the second valve rod and extending from the first valve body to the outside of the valve casing;
• a first actuator disposed outside the valve casing and capable of applying a first biasing force in the vertical direction to the first valve rod;
• a second actuator disposed outside the valve casing and capable of applying a second biasing force in the vertical direction to the second valve rod;
• a first link mechanism disposed between the first actuator and the first valve rod and capable of transmitting the first biasing force;
• a second link mechanism disposed between the second actuator and the second valve rod and capable of transmitting the second biasing force, the second link mechanism having a linking part provided integrally with the second valve rod and a lever which is pin-coupled to the linking part;
• and
• a guide mechanism capable of regulating horizontal displacement of the linking part when the linking part moves in the vertical direction in response to tilting of the lever,
• wherein the guide mechanism includes:
• a support frame disposed above the valve casing;
• a pair of guide plates each extending in the vertical direction, and holding the linking part from both sides in a horizontal direction;
• and
• a pair of support portions each fixed to the support frame, and supporting the pair of guide plates respectively.