What is a Valve?

A valve is a mechanical element used in piping systems to start, stop, mix, control, or regulate the flow or pressure of the fluid by modifying the passage through the pipe. Valves are an essential part of any piping system conveying liquids, vapors, slurries, gases, and mixtures of liquid, and gaseous phases of various flow media. Valves are the most costly rigid piping components in a plant. They can account for up to 20% to 30% of overall piping item costs for a process plant. The size of a valve is decided by the size of its ends connected to the piping system.

Common types of valves can be self-actuated or manually operated or have actuators. Actuators of valves can be electric, pneumatic, or hydraulic powered, or a combination to operate the valve. Valves are made of metals and non-metals depending on the application.