A 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 “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 are durable and usually work to achieve perfect shutoff even after years of disuse. They are therefore an excellent choice for shutoff applications (and are often preferred to globe valves and gate valves for this purpose). They do not offer the fine control that may be necessary in throttling applications but are sometimes used for this purpose.
Ball valves are used extensively in industrial applications because they are very versatile, supporting pressures up to 1000 bar and temperatures up to 752°F (500°C) depending on the ball valve design and material. Sizes typically range from 0.2 to 48 inches (0.5 cm to 121 cm). They are easy to repair and operate.
A ball-check valve is a type of check valve with a ball without a hole for a disc, and is not covered in this article.
The Ballofix was invented by the Danish company Broen, and are still in production.