A ball valve is a form of quarter-turn valve which uses a hollow,
perforated and pivoting ball to control flow through it. It is open
when the ball's hole is in line with the flow and closed when it is
pivoted 90-degrees by the valve handle. The handle lies flat in
alignment with the flow when open, and is perpendicular to it when
closed, making for easy visual confirmation of the valve's status.
Ball valves are durable, performing well after many cycles, and
reliable, closing securely even after long periods of disuse. These
qualities make them an excellent choice for shutoff and control
applications, where they are often preferred to gates and globe
valves, but they lack their fine control in throttling
The ball valve's ease of operation, repair, and versatility lend it
to extensive industrial use, supporting pressures up to 1000 bar
and temperatures up to 752 °F (400 °C), depending on design and
materials used. Sizes typically range from 0.2 to 48 inches (0.5 cm
to 121 cm). Valve bodies are made of metal, plastic, or metal with
a ceramic; floating balls are often chrome plated for durability.
One disadvantage of a ball valve is that they trap water in the
center cavity while in the closed position. In the event of a
freeze, the sides can crack due to expansion of ice forming. Some
means of insulation or heat tape in this situation will usually
prevent damage.Another option for cold climates is the "freeze
tolerant ball valve".
This style of ball valve incorporates a freeze plug in the side so
in the event of a freeze up, the freeze plug ruptures (acts as a
sacrificial disk), thus making for an easy repair. Now instead of
replacing the whole valve, just screw in a new freeze plug.
In the case that a ball valve is used for cryogenics or product
that may expand inside of the ball, there is a vent drilled into
the upstream side of the valve. This is referred to as a vented
ball. Safety is the number one concern when engineers specify a
A ball valve should not be confused with a "ball-check valve", a
type of check valve that uses a solid ball to prevent undesired
Other types of quarter-turn valves include the butterfly valve and
plug valve and freeze proof ball valve.
ANSI Ball Valve
1. Technical Specification
Face to Face:
2.Main Parts and Materials
ASTM A536 60-40-18