Ball valves are commonly made from brass, a metal alloyed from copper and zinc. Brass ball valves are manufactured by casting; the ball is chrome plated to increase its durability. The diameter of the valve varies from mini valves that are less than an inch up to a number of feet.
Brass ball valves are used for shut-off applications because they provide a perfect seal even if they have not been used for long periods of time. They are generally not used in throttling applications because spherical discs do not allow for fine control. Because the actuator has to move only a short distance to open or close the valve, small adjustments and minor movements are difficult to control. Brass ball valves are used by industries that transport water or other liquids as well as gases and some solid-liquid mixtures.
Ball valve manufacturers produce several variations of brass ball valves in terms, ports and size. Two-way ball valves are the most basic and have one straight hole bored through the ball, providing one inlet and one outlet. L type ball valves have two holes that meet in the middle, providing one inlet and two outlets.
The ball can be rotated a quarter turn in order to direct flow one way and, when rotated 180°, directs it the other way. Another quarter turn closes the valve completely. T type brass ball valves have three holes drilled at 90° angles that meet in the center, forming a T. The single inlet can direct the flow into two outlets simultaneously or individually shutting off one or all of the passageways it connects.
Other options include a full port ball valve where the ball itself is larger than the passage size. Because the ball is the same diameter of the pipe, there is no flow restriction. A standard port ball valve has a hole that is smaller than the passageway because the ball is not over sized. Reduced port ball valves have even smaller balls with smaller holes to significantly restrict the flow.