ECOTROL®
Control valve 8C/ 6N/ 6H

The ECOTROL® control valve handles steam, gases, oils and virtually all process liquids. Typical applications include chemical and petrochemical processing, power generation, steel and metals, oil & gas, green energy (including hydrogen and biomass plants), pharmaceuticals, food and beverage, and water treatment. Thanks to its modular construction, the valve can be tailored precisely to the conditions of each individual process.

The ECOTROL® control valve covers a temperature range from –196 °C to +650 °C. Pressure ratings vary by series and span PN 16 to PN 250 / ANSI Class 150 to Class 1500: the 8C and 6N series cover PN 16–63 / Class 150–600, while the 6H series is dedicated to high-pressure service from PN 100–250 / Class 900–1500. This makes the valve equally suitable for cryogenic, high-pressure and high-temperature duty.

The ECOTROL® control valve is offered in the following sizes: 8C series from DN 15 to DN 100 (½″ to 4″), 6N series from DN 125 to DN 700 (5″ to 28″, DN 800 on request), and 6H series from DN 15 to DN 400 (½″ to 16″, DN 500 on request). This range covers virtually any flow requirement, from small bypass lines to the main piping of large compressor trains.

Standard flow characteristics are equal-percentage or linear; a modified linear characteristic is available on request. Inherent rangeability is up to 50:1 for the 8C series and 40:1 for the 6N and 6H series. This wide controllable range delivers precise control even under highly variable load profiles and helps avoid over-sizing the valve.

Three baseline solutions are offered: a maintenance-free, self-adjusting PTFE V-ring packing with an additional fine-sealing element (certified to TA-Luft and ISO 15848), an adjustable gland packing with graphite, pure-graphite or Inconel rings combined with the patented OPTIPRESS® preloading system, and a hermetically tight, double-wall bellows seal in 1.4571 stainless steel (optionally Inconel 625 or Hastelloy® C276) with an additional safety gland. This allows the optimum seal to be selected for any combination of medium, pressure and emission requirement.

Metal-seated versions reach Class IV to IEC 60534-4 as standard (0.01 % of Kvs); Class V is available as an option. With a soft seat (PTFE/EPDM, PTFE/FKM or trapezoidal ring), Class VI – virtually bubble-tight shut-off – is reached. A special feature is the patented ECOTROL® soft seal with metallic back-up, which has proven its reliability in pressure swing applications over more than one million operating cycles.

Body materials are selected to suit the duty: cast steel (1.0619 GP240GH), creep-resistant steels (1.7357 G17CrMo5-5, 1.7379 G17CrMo9-10, 1.4931 for temperatures up to 600 °C), low-temperature carbon steel (1.6220 G20Mn5) or stainless steel (1.4408 G-X5CrNiMo19-11-2). ASME equivalents include A216 WCB, A217 WC6/WC9, A352 LCB and A351 CF8M. For abrasive service, seat and plug can be supplied in hardened 1.4112, tungsten carbide or ceramic; for corrosive duty, special alloys such as Hastelloy® and Inconel® are available.

The patented ECOTROL® clamp-seat system is the cornerstone of its serviceability: seat and plug can be exchanged on-site by the operator’s own personnel, without special tools and without machining work. Because stem and plug are separately replaceable, spare-parts inventory and stocking costs drop substantially. In combination with the modular architecture, downtime is significantly reduced compared with conventional control valves.

The standard actuator is the pneumatic multi-spring 812 ARCAPAQ® diaphragm actuator, providing high positioning accuracy and shut-off thrust. Optional choices include single-spring actuators of the 811 series (UV), the MA60 multi-spring actuator, robust piston actuators of the 812 DWK and 814 series, as well as electric and electro-hydraulic actuators. This allows the actuator to be matched precisely to the required thrust, stroking speed and fail-safe action – ATEX-compliant configurations for hazardous areas included.

ARCA optimises the trim using CFD flow analysis to minimise pressure loss, sound emission and the risk of cavitation. Depending on the duty, single-stage or multi-stage parabolic plugs, cage plugs with seat retainers or rotary-disc trims are deployed. This precisely tailored geometry delivers best-in-class control accuracy, long service life and low operating costs – even in demanding high-pressure-drop applications.

For sizing and specification, the ARCA-VENA software is available; it calculates Kvs values, screens for cavitation and noise risk, and produces the complete valve specification. The ARCAonsite platform provides global access to the data sheet, equipment passport, maintenance history and spare-parts information via a QR code on the valve itself. For commissioning and operation, the intelligent ARCASMART and ARCAPRO® positioners add diagnostic and communication capabilities over HART, PROFIBUS PA and FOUNDATION Fieldbus.

Depending on series and nominal size, Kvs values range from 0.01 m³/h up to 7,000 m³/h (Cv 0.01 to 8,155 gal/min). The valve therefore covers both very low flows – e.g. with the rotary-disc trim – and very high volume flows up to DN 700 on the same engineering platform. Final selection is made on the actual process data using ARCA’s in-house sizing tool ARCA-VENA.

For cryogenic service down to –196 °C, ARCA provides a dedicated extended bonnet running inside a thin-walled insulating column, minimising heat conduction and radiation losses. For temperatures above 250 °C, finned bonnet extensions combined with graphite packings are used; above 450 °C the finned extension is dimensioned so that the temperature in the packing area remains below 450 °C even in worst-case conditions. As an alternative, the hermetically tight bellows seal is available, rated up to +500 °C depending on the variant.

Large ECOTROL® control valves up to DN 700 are frequently deployed as anti-surge control valves on turbo-compressors, as bypass valves in steam systems, or as primary control valves in power generation. Their high Kvs values, fast stroking times and accurate control characteristics make them ideally suited to handling large volume flows while maintaining plant safety.

Depending on the series, actuator, seat diameter and trim (balanced or unbalanced), differential pressures of more than 200 bar are achievable. The exact values are tabulated in the respective technical data sheets and confirmed during sizing with ARCA-VENA. For very high differential pressures, a pressure-balanced trim is recommended; it allows a noticeably smaller actuator to handle the same shut-off load.

Actuator selection is driven by the maximum differential pressure, the required stroke, the thrust needed for tight shut-off, the desired stroking time and the chosen fail-safe action (air-to-open / spring-to-close, or vice versa). ARCA provides detailed sizing tables in the technical documentation. With a pressure-balanced trim, a smaller actuator is often sufficient – saving installation envelope and capital cost.

ARCA offers a modular service portfolio: ARCAlaunch supports commissioning – including flushing services, ARCAcare provides preventive maintenance under a fixed schedule, ARCAsafe secures the availability of spare and wear parts, ARCA24/7 guarantees telephone support around the clock, and ARCAknowhow delivers hands-on and theoretical training for operator personnel. Complementing the package, ARCAonsite makes all relevant documents digitally available at the valve itself.

ECOTROL® control valves comply with the Pressure Equipment Directive 2014/68/EU (Module B EC type-examination by DNV, certificate PEDB0000014), pressure-containing shell design to EN 12516-2 / ASME B16.34, seat leakage testing to IEC 60534-4 / EN 1349 and component testing to EN 12266-1. With respect to explosion protection, an ignition-hazard assessment to DIN EN ISO 80079-36 has shown that the valve itself contains no inherent ignition source and is therefore not covered by the ATEX Directive 2014/34/EU (manufacturer’s declaration available) – actuators and positioners are ATEX-certified separately. Optional designs and certificates to TA-Luft, ISO 15848, NACE MR0175, FDA / EC 1935/2004 and DNV Marine Type Approval (TAP00002TU) are available – making the valve suitable for sensitive and highly regulated applications.

Three aspects set the ECOTROL® control valve apart: first, the patented ECOTROL® clamp-seat system that enables maintenance without special tools and dramatically reduces downtime; second, a fully modular design that adapts flexibly to almost any process; and third, a comprehensive digital ecosystem built around ARCA-VENA, ARCAonsite and the ARCASMART / ARCAPRO® positioners. Together, these factors translate into significantly lower life-cycle costs and very high plant availability.

For noise- or cavitation-critical applications, several trim variants are available: multi-stage parabolic plugs (P3, P5) break down the pressure in successive stages, cage plugs with a low-noise drilled cage split the flow into many small jets, and a seat retainer (LK / SLK) below the seat ring protects the body from cavitation damage. Additionally, a low-noise distance tube (LN) can further reduce the sound pressure level. With these measures, noise levels can be reduced by up to 30 dB(A) and service life is significantly extended even at high differential pressures.

As standard, the ECOTROL® control valve is supplied as a flanged valve to DIN EN 1092-1 (Form B1) or ASME B16.5 (RF and RTJ). Butt-weld ends to DIN EN 12627 / ASME B16.25, extended weld ends for a reduced heat-affected zone, and flanges with tongue, groove or male/female faces are available on request. Face-to-face dimensions follow EN 558 Series 1 (PN 16/40), Series 2 (PN 63) and ISA 75.08.01 (ANSI). The valve therefore fits into virtually any existing piping layout without custom lengths.

ARCAonsite is ARCA’s digital platform that links every valve to a QR code on its nameplate. With a quick scan from a smartphone or tablet, maintenance personnel anywhere in the world gain direct access to the equipment passport, data sheet, operating manual, spare-parts list, sectional drawings and complete maintenance history. This eliminates search time, prevents errors and ensures uninterrupted lifecycle documentation – even across changes in ownership or maintenance staff.

Recommended installation is in a horizontal pipe run with the actuator above the valve. A straight pipe section of at least 10 × nominal diameter without internals should be provided both upstream and downstream as a stabilisation zone. A bypass line with isolation valves, plus a strainer upstream of the valve, are recommended. Before initial start-up, the piping system should be flushed – ARCA provides dedicated flushing kits and the ARCAlaunch service package for this. Thermal shock must be avoided: above a temperature differential of 300 K, the recommended ramp rate is no more than 2 K/min.

Yes. For cryogenic service with media such as LNG, liquid nitrogen or hydrogen, ARCA offers a dedicated low-temperature design with extended bonnet (DEK5), qualified cryogenic materials (e.g. 1.4408 / A351 CF8M with Charpy impact testing), and either a bellows or a PTFE V-ring stem seal. The 8C, 6N and 6H series hold a DNV Marine Type Approval (TAP00002TU, valid until 04/2029) for use on gas tankers, in LNG fuel systems and in shipboard piping. This makes the ECOTROL® control valve an established choice in the growing markets around liquefied gases and green energy.