Valves are mechanical devices that control the flow and pressure of liquids, gases, and slurries within a system. They are also known as regulators and are used in a wide variety of applications.They can be used for a broad range of applications within water supply, wastewater treatment, fire protection and gas supply, in the chemical and oil industries, in fuel handling systems, power generation etc. These valves can be operated by handles, gears or actuators according to specific needs.
The three common valve functions include stopping and starting flow, throttling (control) flow, and acting as a non-return check for flow (check). Industrial valves can vary greatly in size and design but there are several basic components to valve functionality.