Precise actuator sizing and selection is a fundamental factor to consider while deciding on a valve automation solution. Making the correct decision warrants dependability and enduring productivity, especially for applications in unforgiving environments. Components such as seal life, side loading, and working conditions will ultimately drive design standards that will determine MTBF (mean time between failures).
Pneumatic actuators are globally recognized and accepted due to their high sheer torque, cycle time, and simplicity of use. It is a technology that has survived the times with the addition of Digital communication and automation protocols. But in today's motion control industry, pneumatic actuators have three significant short comings; operative expenditures, system maintenance and controllability. Numerous operators are becoming mindful of the fact that compressed air is not a free utility. The energy it takes to compress air and move it through a plant, is becoming a factor. Dealing with connection leaks, keeping air clean and dry and friction losses, can become time consuming and costly in both down time and maintenance hours.
Pneumatic control stays a respectable choice when promptness, simplicity, and established technology are essential. In addition, pneumatic actuators have adequate to high load capability at great speeds making them very desirable in many Open/Close applications.
Electrically actuated systems are commonly used in automation applications because they are simple to interface with electrical control systems. In an electrically powered automation solution, the actuator and the controller are driven from the same power source, making installation simpler for the end user. Also, in most circumstances, electric actuators are going to have a longer cycle time than pneumatics. Electric actuators are more expensive up-front per unit which can be a discouraging factor when looking at side by side pricing. Depending on the specific application, this may be the deciding factor. But the real cost savings will be seen in reduced down time and less maintenance a year or two down the road.
My conclusion to the ultimate question of Electric vs. Pneumatic: you will save money in the long term by choosing an electric actuator. But the choice of which is the better actuator is dependent on the specific job application. Both have their Pros & Cons and need to be weighed out based on the job requirements.