Control valves control the liquid flowing through its body, unlike gate valves which isolate two different liquids. They have actuators which provide force to operate the valve and these control valves are categorized based on these actuating mechanisms. Pressure sensors trigger these actuators. Pneumatic actuators use air or gas to modify the width of the orifice of the control valve, whereas Electric actuators do the same using a motor. Hydraulic actuators are similar to Pneumatic actuators which use hydraulic fluids like oil instead of gas or air.