BALL VALVE

This 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 in line with the port position letting you “see” the valve’s position. The ball valve, along with the butterfly valve and plug valve, are part of the family of quarter turn valves.
Ball valves usually work to achieve perfect shutoff even after years of disuse. Thus they are durable. An excellent choice for shutoff applications (and are often preferred to globe valves and gate valves for this purpose). The fine control that may be necessary in throttling applications is not offered by ball valve but they are sometimes used for this purpose.