Three-way ball valves are the most common types of ball valves. Three-way ball valves are especially useful because they can be set up in ways that simplify the control of gas and fluid flow. For example, they can be used to divert the flow of oil from one tank to another.

Three-way ball valves can :

Cut of or shut off flow
Switch flow between two different sources
Combine the flow from two different sources
Alternate flow between two different destinations
Divert flow coming from one source to another destination
Split flow coming from one source between two outgoing destinations