Pneumatic Actuators are the most commonly used option where electric power sources are of limited capacity or unavailable. They suit a range of different valves except the very largest sizes of valves with high differential pressures. They are usually designed for use on pneumatic supplies of 4 to 6 barg nominal pressure. Air supply systems require a compressor working in conjunction with an accumulator plus appropriate filters to ensure that any moisture, dirt and oil are removed to keep the air clean and dry.
Using a pneumatic actuator is a convenient and economical source of power. They also have different failsafe options to put the valve into an open or closed position should there be a loss of air pressure.
Electric Actuators are a conventional way of providing a versatile method of valve operation. Smaller electric actuators often use either a single phase AC or DC power supply. The three phase motor option provides the most efficient, robust and simply controlled form of electrically power prime mover for larger valve applications.
An advantage of using an electric actuator is that they have a “flat line” torque output which makes sizing easier. It’s also energy efficient and has ability to interface with modern computerised and telemetric remote control systems.