Abstract: There are provided a steam valve and the like capable of preventing breakage of an auxiliary valve element and effectively suppressing the occurrence of a leak of steam in the auxiliary valve element. In the steam valve of an embodiment, the auxiliary valve element is structured to be in an open state in which the valve rod moves in an opening direction to increase a distance between an auxiliary-valve cap and a main valve element, thereby opening an auxiliary-valve steam introduction hole, and to be in a fully-closed state in which the valve rod moves in a closing direction in which the main valve element is closed to bring the auxiliary-valve cap and the main valve element into contact with each other, thereby closing the auxiliary-valve steam introduction holes.

Abstract: In a steam valve of an embodiment, a valve element of a comprises: a first valve element part positioned in the closing direction, and including a first valve element part outer peripheral surface configured to surround the valve rod; and a second valve element part positioned in the opening direction, and including a second valve element part outer peripheral surface configured to surround the valve rod. The first valve element part outer peripheral surface is a curved surface formed to have a diameter increased toward the opening direction. A diameter of boundary position between the first valve element part outer peripheral surface and the second valve element part outer peripheral surface is the same as a seat diameter of valve seat at which the valve element is brought into contact with the valve seat when the steam valve is set to a fully-closed state.

Abstract: A steam valve of an embodiment includes a casing, a valve rod, a valve element, and a valve seat. At the casing, the steam flows from an inlet into an inner space, and flows out of an outlet. The valve rod is accommodated in the inner space. The valve element is coupled to the valve rod at the inner space. The valve seat is fixed to the casing at the inner space, and includes a part where the valve element is in contact by moving together with the valve rod along an axis of the valve rod. Each of the valve seat and the casing includes a plane facing via a gap at a downstream side than a part where the valve seat and the valve element are in contact at the inner space. The valve seat has a cover part which covers the gap at the inner space.

Abstract: A steam valve of an embodiment includes a casing, a valve rod, a valve element, and a valve seat. At the casing, the steam flows from an inlet into an inner space, and flows out of an outlet. The valve rod is accommodated in the inner space. The valve element is coupled to the valve rod at the inner space. The valve seat is fixed to the casing at the inner space, and includes a part where the valve element is in contact by moving together with the valve rod along an axis of the valve rod. Each of the valve seat and the casing includes a plane facing via a gap at a downstream side than a part where the valve seat and the valve element are in contact at the inner space. The valve seat has a cover part which covers the gap at the inner space.