Below is a list of Brass Ball Valve manufacturers from Pittsburgh, Pennsylvania. Brass ball valves are mechanisms that can completely close off a pipeline through use of a spherical element. The ball has a hole through the center that allows fluids to flow through it when the valve is open. When the control lever or handle is rotated a quarter turn manually or by an automatic actuator, the ball inside turns so that the open ends of the hole, or port, are not in line with the pipe but face the walls of the valve, blocking off the flow.