3-way valves are typically manufactured in a T- or L-shape so that fluid can flow through passageways inside the rotor, the rotating part of the valve. The most common use for 3-way ball valves is that flow coming in one port can be directed to either the second or third port. One use for the T-valve is to allow a connection of one inlet to either or both outlets.
The L-valve is used to disconnect both inlets from one outlet or it can connect one of two inlets to one outlet. Other kinds of 3-port valves can be designed for other possible flow-directing schemes and positions. 3-way ball valves are particularly useful for liquids or gases moving in many directions, such as a faucet that distributes both cold and hot water. 3-way ball valves can be manufactured with stainless steel or brass.
Advances in ball valve designs and materials have significantly increased their popularity. Ball valves can be used for isolation of systems, regulation of low flow (e.g. throttling the flow of air at differential pressures up to one thousand psi) and backflow (e.g. water supply systems) prevention, but only with a swing check component.
3-way ball valves can handle high pressures and large volumes of liquids, gases and suspended solids. Ball sizes less than two inches are generally one, two or three piece designs. These valves range from inexpensive and throw-away to expensive and repairable. Three piece design valves contain a ball, stem and seats that can be removed from the pipeline for easy cleaning of deposited sediments and polishing without removing the pipes from the valve body.