Industrial control valves are used to control the flow of liquids, gases, and other materials in industrial processes. They are used in a variety of applications, including chemical, petrochemical, oil and gas, power generation, and water and wastewater treatment. Control valves are designed to regulate the flow of a process fluid, such as water, air, steam, or other liquids, by opening, closing, or partially obstructing the flow path. They are used to maintain a desired pressure, temperature, or flow rate in a process system. Control valves are typically operated by an actuator, such as a motor, pneumatic cylinder, or hydraulic cylinder, which is connected to the valve stem. The actuator is controlled by a controller, which is typically a computer or other electronic device.