The main difference between pneumatic and mechanical actuators is their working speed. The two systems are so distinct, that one can not replace the other with a drop-in. Each one has its own intrinsic benefits and disadvantages:
Advantages of Pneumatic actuators:
- The pneumatic actuators ‘ greatest advantage is their failsafe operation. Through engineering the compressed spring, the designer will decide whether the valve will break, either closed or open, based on process protection.
- Provide high power and speed, easy to adjust and independent of each other.
- Most economical when the scale of deployment matches the capacity of the compressor.
- Provide inherent safety and are ideal for explosive and hazardous environments.
- Have a delayed response which makes them ideal for resilience to minor disruptions in source pressure changes
Limitations of Pneumatic actuators:
- Maintenance and operating costs can be high, especially if there has been no serious effort to quantify and minimize the costs.
Advantages of Electrical actuator:
- Provide precise power and placement as opposed to pneumatic actuators.
- Response time is essentially instantaneous.
- High degree of stability.
- Cost of operation small. Controllers and low stress drivers use much less energy.
- Help adapt machines to flexible processes.
Limitations of electrical actuator:
- The main disadvantage of an electric actuator is that if a power failure happens, the valve stays in the last position and the fail-safe position can not be easily obtained unless a suitable supply of stored electrical energy exists.
- Costs higher than pneumatic actuators. The total cost ranges between $800 and $3,000 and more.
- The actuator must be in an area which is made safe. Not generally recommended for flame retardant atmospheres
