Abstract: A manual device for a valve has: a movable valve opening member sustained rotatably and disposed in a valve body; an opening and closing of the valve for controlling the opening and closing oi a fluid passage; a notch plate connected with one end of a stem which is pivotably sustaining the valve; a notch plate moving freely in axial direction on the stem and which rotates synchronously with the stem; a manual and oprative knob adhered to the notch plate; a casing adhered to the valve body, so that the casing stores the notch plate and guides the movement of the notch plate freely in the axial direction and guides rotation of the notch plate; a notch means preventing the extra rotation of the notch plate by mutual engagement between the notch plate and the casing; and a notch plate which is constantly pressurized to keep the engagement.

Abstract: A seat ring is resiliently fitted into upper and lower main bodies of a butterfly valve divided in a horizontal direction of piping so as to prevent a fluid from being leaked from the butterfly valve.