Ball Valve, swivel joint || DOTEC CO.,LTD. Ball Valve, Cryogenic Ball, Top Entry Ball, Metal Seat Ball, swivel joint, floating ball valves, bolted bonnet, cryogenic ball valves, piping materials, swing check valves, cryogenic ball valves, check valve ball valve is a valve with a spherical disc, the part of the valve which controls the flow through it. The sphere has a hole, or port, through the middle so that when the port is in line with both ends of the valve, flow will occur. When the valve is closed, the hole is perpendicular to the ends of the valve, and flow is blocked. The handle or lever will be inline with the port position letting you