Product Overview

The EEI 585.C​ (also referenced as 585-C-EEI​ or EEI 585 C) is a heavy-duty, double-acting quarter-turn rotary actuator developed by EEI – Elettromeccanica Industrial (Italy) for the reliable automation of ball valves, butterfly valves, plug valves and dampers in process industries. Belonging to the well-established 580/585 series of symmetric twin-piston rack-and-pinion actuators, the EEI 585.C​ converts pneumatic or low-pressure hydraulic energy into precise 90° rotary motion (optionally adjustable up to 180°) via two opposed pistons driving a centrally mounted pinion gear.As a true double-acting unit, the EEI 585.C​ applies pressurized fluid alternately to opposing sides of the piston pair—producing forceful open and close strokes with no spring-return bias. On loss of air/gas supply the actuator will typically remain in its last position (fail-in-place), which is a critical safety characteristic for many ESD and modulating applications. The internal geometry of the symmetric rack-and-pinion design ensures uniform torque output throughout the stroke and eliminates the torque differential seen in scotch-yoke alternatives of similar size.Engineered for continuous-duty process service, the EEI 585.C​ features a hard-anodized extruded aluminum body, hardened alloy-steel pinion with through-bored output shaft conforming to ISO 5211 / DIN 3337, externally accessible travel limit screws, and an integral visual position indicator. NAMUR-standard accessory pads accept solenoid valves, pneumatic positioners, limit-switch boxes and proximity sensors without special brackets. Whether deployed as original equipment on new valve packages or as a direct interchange/replacement for Biffi 580-series or equivalent rack-and-pinion actuators, the EEI 585.C​ delivers proven performance in demanding automation loops.

Technical Specifications