Processing Magazine

Pneumatic actuators provide long-lasting performance in harsh applications

July 15, 2009
The pneumatic actuator is a 90-degree (quarter-turn) rack and pinion design available in both double-acting (air-to-air) and single-acting (air-to-spring) models. When the actuator is energized, dual opposing pistons with graphite nitrile rolling O-rings and self-lubricating guide bands drive a single pinion gear connected to the final output drive shaft. This design provides for fewer moving parts and provides for a durable long-performing actuator. Air-to-spring models can be configured for spring clockwise (fail closed) or spring counterclockwise (fail open) rotation, simply by reversing the internal pistons and rotating the pinion gear and output shaft. The actuators are available in three materials: PAG (glass-filled polyamide) body; 316 stainless steel body; and cast aluminum body. The actuators feature one-piece stainless steel shafts with female output star pattern outdrives, ISO F-series standardized valve mounting bolt patterns, and Namur standard solenoid and limit switch interface mounting details. Output torques range from 138 inch-lbs to 40,818 inch-lbs (based on 80 psi supply air) for air-to-air models and 59 inch-lbs to 15,660 inch-lbs (80 psi supply air required) for air-to-spring models. Can be factory or field mounted on any of the manufacturer’s ball valve or butterfly valve, as well as most other manufacturers’ ball or butterfly valves.