Description
A valve is a device that regulates, directs or controls the flow of
a fluid (gases, liquids, fluidized solids, or slurries) by opening,
closing, or partially obstructing various passageways. Valves are
technically valves fittings, but are usually discussed as a
separate category. In an open valve, fluid flows in a direction
from higher pressure to lower pressure.
The simplest, and very ancient, valve is simply a freely hinged
flap which drops to obstruct fluid (gas or liquid) flow in one
direction, but is pushed open by flow in the opposite direction.
This is called a check valve, as it prevents or "checks" the flow
in one direction.
Valves have many uses, including controlling water for Irrigation,
industrial uses for controlling processes, residential uses such as
on / off & pressure control to dish and clothes washers &
taps in the home. Even aerosols have a tiny valve built in. Valves
are also used in the military & transport sectors.
