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Description
Technical Specifications
| Product Model | EEI 585.C (585-C-EEI / EEI 585 C) |
|---|---|
| Manufacturer | EEI (Elettromeccanica Industriale) / Biffi 580 Series Heritage – Flowserve Compatible |
| Product Type | Double-Acting Rack & Pinion Quarter-Turn Pneumatic Rotary Actuator |
| Action Type | Double Acting (air-to-open / air-to-close; fail-in-place on air supply loss) |
| Output Motion | 90° standard (adjustable ±5° per end); 180° versions available by frame size |
| Output Torque @ 5.5 bar | Frame-size dependent; typical range 60 Nm – 6000+ Nm across series (consult torque table) |
| Operating Pressure (Pneumatic) | 3 bar (min) – 8 bar (std max); some frames rated to 10 bar |
| Hydraulic Service Pressure | Up to 30–80 bar (hydraulic-capable variants, model suffix dependent) |
| Air Supply Port | G 1/4″ or G 1/2″ BSP / NPT (per frame size); NAMUR interface ready |
| Mounting Flange | ISO 5211 (F03 / F04 / F05 / F07 / F10 / F12 / F14 / F16 per size) |
| Output Shaft / Drive | ISO 5211 square or keyed per valve stem spec; alloy steel, through-bored |
| Body / Cylinder Material | Extruded aluminum alloy, hard anodized (std); epoxy polyester coat optional |
| Piston / Rack | Aluminum alloy with PTFE wear strips; matched to hardened steel pinion |
| Seals / O-Rings | NBR (nitrile) std: -20 °C to +80 °C; FKM (Viton) optional: -30 °C to +150 °C |
| Travel Limit Adjustment | External hex-head screws, independently adjustable open & close ends |
| Position Indicator | Molded polyamide visual pointer with OPEN / CLOSED dial |
| NAMUR Accessory Pads | Yes – both sides, for Namur solenoid, positioner, limit switch box |
| Ingress Protection | IP65 std (IP67 optional with sealed accessory covers) |
| Typical Weight | 2.5 kg (smallest frame) to 120+ kg (largest bore frame) |
Main Features and Advantages
Symmetric twin-piston rack-and-pinion drive:The EEI 585.C employs two opposing pistons with precision-machined rack teeth meshing a central pinion. This symmetric layout produces essentially constant torque through the full 90° sweep and yields smooth, chatter-free valve operation even under high differential pressure—unlike scotch-yoke types that exhibit torque variation near end positions.True double-acting with fail-in-place behavior:With no spring-return bias, the EEI 585.C develops equal torque in both directions and stays put on loss of air, avoiding spurious valve movement that could compromise process safety. When specified as part of an ESD loop with a monitored trip solenoid and partial-stroke test (PST) valve, the EEI 585.C integrates cleanly into SIL-rated shutdown architectures.Industrial-grade corrosion protection:The hard-anodized extruded-aluminum cylinder of the EEI 585.C resists salt-spray and chemical atmospheres, while stainless-steel fasteners and PTFE piston wear bands eliminate metal-on-metal sliding. Optional FKM seals and epoxy-over-anodize finish extend the envelope to high-heat or sour-gas locations.NAMUR accessory readiness:Both side faces of the EEI 585.C carry NAMUR-slotted mounting pads. A 5/2 or 3/2 Namur pilot solenoid, smart positioner, or inductive/cam-actuated limit switch box bolts directly—no adapter plate, fewer potential leak paths, faster loop checkout.Field-adjustable travel stops:Independent open/close limit screws let technicians fine-tune stroke endpoints of the EEI 585.C without decoupling the actuator from the valve yoke. This is particularly valuable during initial commissioning, valve reseating, or re-characterization after seat replacement.Direct interchange with 580-series predecessors:The EEI 585.C shares ISO 5211 flange patterns, bolt circles and overall dimensional envelopes with legacy Biffi / Flowserve 580-series double-acting actuators, making it a drop-in spare for plant lifecycle refresh programs without re-machining valve adapters.
Application Field
The EEI 585.C is specified wherever large or medium quarter-turn valves require dependable, high-torque bidirectional pneumatic actuation in continuous or batch process plants. In upstream and midstream oil & gas facilities the EEI 585.C automates ANSI 150–600 class ball valves on manifold headers, pig-launcher launches, slug-catcher isolation and meter-run bypasses—often paired with an ESD solenoid and PST valve to meet SIL-2/SIL-3 requirements while retaining fail-in-place action. Refinery and petrochemical units apply the EEI 585.C to butterfly and eccentric-plug control valves in fuel-gas skids, cooling-water circuits and catalyst-regeneration lines where high break-away torque is needed to unseat deposits.Power generation stations install the EEI 585.C on condenser cooling-water intake butterfly valves, auxiliary steam header ball valves and demineralized-water isolation points; the IP65/IP67 rating and anodized finish suit coastal or high-humidity turbine hall environments. Water & wastewater treatment plants use the EEI 585.C on penstocks and aeration-system butterfly valves, leveraging low maintenance demand and broad seal-option availability. Where instrument air is unavailable, hydraulic-rated variants of the EEI 585.C can be driven from a local HPU, extending applicability to marine-deck and offshore topside valve packages. In every case the EEI 585.C mounts directly to ISO 5211-pattern valve yokes and can retrofit Biffi 580-series or generic rack-and-pinion units of matching flange size.
