SIL 3 Heavy Duty Pneumatic Actuator

Acrodyne has launched a heavy-duty scotch-yoke pneumatic actuator which has been designed for use in chemical, refining, oil and gas and general industrial applications. Designed to optimise plant and personnel safety through compliance with IEC 61508 (Functional Safety Related Systems), Safety Integrity Level 3, the Automax RG Series offers an extended life cycle and reduced maintenance requirements.


‘The actuator’s IP67M [temporary submersion] rating and marine-grade epoxy surface treatment provide maximum integrity in harsh corrosive atmospheres such as offshore installations. To reduce product modification and installation costs it features a modular design with independent modules for the body, pneumatic and spring segments. The RG’s pneumatic and spring modules can be changed on location to modify the actuator torque output and fail rotation direction, eliminating the need for a new actuator if these changes are required.

With the pull-to-compress spring module, manual overrides can be added for spring-return or double-acting operation. The pressure-module piston incorporates dual-wear bands providing a forward wiping action to extend the life of dynamic squad seals. Inside the pressure and torque module, critical sealing and load bearing surfaces are honed and hard-chrome plated to reduce surface wear and increase corrosion resistance. A hard-chrome plated steel guide bar provides optimal support of the transverse loads.

Coupling the yoke are aluminium bronze slider blocks to minimise contact stress and ensure high cycle life to increase production uptime and reduce maintenance costs. The new design of the Automax RG Series represents a 20 per cent weight reduction and a 20 per cent end-to-end length reduction compared to previous models. The actuator features an expanded torque output range of 248,566Nm while the availability of more than 100 output torque profiles enhances valve automation selection and reduces the weight, size and cost of the actuator.

The Automax RG Series has been designed for use in quarter-turn automation duties for ball, plug and butterfly valves and rotary dampers in chemical, refining, oil and gas and general industrial applications. The actuator conforms to global mounting and accessory mounting standards including International Organization for Standardization (ISO) 5211 valve interface with MSS option and NAMUR VDI/VDE 3845 compliance.