A ball valve is a flow control device which uses a hollow, perforated and pivoting ball to control liquid flowing through it. It is open when the ball's hole is in line with the flow inlet and closed when it is pivoted 90-degrees by the valve handle, blocking the flow.Ball valve is the most used fluid shutoff valve in upstream oil and gas production facilities, both onshore and offshore. They are also used in fuel gas systems feeding furnaces. Plug valves present the following advantages: Resistance to high pressure.