Rotary

Rotary pneumatic actuators are used to automate quarter-turn valves, including ball, butterfly, and plug valves, in industrial services such as water, air, low-pressure steam, chemicals, fuels, and process fluids. Actuator selection should be based on the valve breakaway and seating torque under differential pressure, available instrument air pressure, operating frequency, required response time, and the fail position required by the process.

This category includes Actreg ADA/ASR and SIRCA AP/APM actuators in double-acting and spring-return configurations. Double-acting actuators require air pressure for both opening and closing strokes. Spring-return versions are applied where the valve must move to a predefined fail-open or fail-close position upon loss of air supply or control signal.

Actreg ADA/ASR actuators use a rack-and-pinion mechanism, with 90° rotation ±5° adjustment through external travel stops, maximum operating pressure of 8 bar, NAMUR interface for solenoid valve mounting, VDI/VDE 3845 interface for accessories, and mechanical connection according to ISO 5211 / DIN 3337. Available temperature ranges extend from -60 °C to +150 °C, depending on O-ring and pinion material selection.

SIRCA AP/APM actuators cover torque outputs from 2.4 to 7500 Nm, with operating pressure ranges of 2-8 bar for double-acting and 3-8 bar for single-acting versions. Standard temperature range is -20 to +80 °C. Design and mounting references include UNI EN 15714-3, ISO 5211, and VDI/VDE 3845, with optional ATEX and SIL certification to IEC 61508 / IEC 61511 where required by hazardous area classification or safety instrumented functions.

During specification, the torque safety factor, air quality and dew point, spring sizing, stroke adjustment, limit switches, positioner selection, mechanical travel stops, and maintenance access should be checked. Contaminants, moisture, or insufficient air pressure can affect response time, available output torque, and final shutoff tightness at valve closure.