A cone valve has a movable internal part that is cone shaped and is opened when the rotating ______ is turned through an angle of 90 degrees

• A. stem
• B. handle
• C. shaft
• D. plug

Answer: (D)

In a plug valve, the component that actually controls flow is the cone-shaped plug itself. This plug rotates inside the valve body, and its conical surface seats against the matching seat to seal. When you turn the plug about 90 degrees, the port on the plug aligns with the inlet and outlet, allowing flow, or misaligns to stop it. The other parts you might see—stem, handle, shaft—are simply the means to rotate the plug; they aren’t the cone-shaped movable part that regulates flow.