Isis brass ball valve by Zetco

A ball valve is an extremely durable stop valve that is designed primarily for On/Off function. They provide tight shut-off and high capacity with just a quarter turn to operate. The position of the handle immediately indicates whether the valve is open or closed. In the open position there is virtually no obstruction to flow, and head loss through full bore ball valves is almost negligible. Along with being easy to monitor, ball valves have an advantage in that the seat performs a self-wiping action, preventing build up of foreign particles within the valve.

The body of ball valves may be manufactured from a wide variety of materials, including Brass, Stainless Steel, PVC, or many others

There are three general types of ball valves: full port, standard port and reduced port.

In a full port ball valve the hole in the ball is the same size as the hole in the pipe, flow is unrestricted and there would be minimal friction loss.

A standard port ball valve is generally less expensive, but has a smaller ball and hence a smaller bore. Flow through this valve is one pipe size smaller than the valves pipe size resulting in slightly greater friction loss than a full port ball valve.

In a reduced port ball valve, the bore through the valve is generally two pipe sizes smaller than the valves pipe size, once again this results in greater friction loss than a standard port ball valve.

Ball valves are extremely versatile and can handle many different types of liquids and pressures. It is important to consult the manufacturer's technical data sheets prior to installation, this ensures the correct valve is being installed for the application. New valve designs, have also meant some types of ball valves may now be used in "High-Vacuum" applications. Some ball valves may also be fitted with Pneumatic actuators.