Valves that are controlled by pneumatic, electric, or hydraulic actuators are known as what?

Valves that are controlled by pneumatic, electric, or hydraulic actuators are referred to as control valves. These types of valves are specifically designed to regulate flow and pressure within a system, allowing for precise control over process variables. The actuators provide the necessary force to open, close, or modulate the valve position automatically, based on signals from a control system.

Control valves are essential in various applications where maintaining specific flow rates or pressures is crucial for safe and efficient operation. They are widely used in industries such as oil and gas, chemical processing, water treatment, and power generation. Unlike manual valves, which require physical operation by personnel, control valves can respond automatically to changes in system conditions, ensuring optimal performance and reducing the risk of human error.

The other types of valves mentioned, such as diaphragm valves and gear-operated valves, each have specific functions and applications, but they do not inherently feature the automated control capabilities associated with control valves.