Valve

Mechanical or electromechanical device by which the flow of a gas, liquid, slurry, or loose dry material can be started, stopped, diverted, and/or regulated. The main types of values include: (1) Isolation valve: on/off valve that typically operates in two positions; the fully open and fully closed position. (2) Switching valve: usually a 3-way valve that converges and divert fluid flow in a piping system. (3) Control valve: regulate the fluid flow in a piping system.