A valve is a device that regulates the flow of a fluid by opening, closing or partially obstructing a passageway.
Modern control valves operate on sophisticated automation systems that are based on external input. The valve is used to regulate flow based previously determined set points or variables, for example. These types of valves require an actuator, which will position the valve accurately depending on its input and setup. Actuators can be electrical, hydraulic or pneumatic, depending on the application and its environment.
Valves are used in a wide variety of applications across many industries, including oil drilling controls, steel mills, chemical processing plants and refineries, HVAC systems, and more.