DUALVENT
Double-seated valve 250 / 280

DUALVENT is offered in two series: Series 250 covers DN 50 to DN 350 at PN 10 to PN 40, while Series 280 is designed for higher pressures and covers DN 40 to DN 250 at PN 63 to PN 160. The permitted fluid temperature range extends from –10 °C to +530 °C.

Both plugs share a common stem and are dimensioned so that the pressure load on the upper plug acts in the flow-to-close direction while the load on the lower plug acts in the flow-to-open direction – or vice versa. Because the forces oppose each other, only a small net thrust has to be applied by the actuator. This makes it possible to control very high flow rates and differential pressures with significantly smaller actuators, saving installation space, energy and capital cost.

DUALVENT is the preferred choice in rugged industrial applications – above all in the steel industry (e.g. continuous casting plants or rolling-mill cooling), chemical and petrochemical processes, and wherever dirty media (particulates, scale, coking residues) have to be controlled reliably while delivering high flow rates within a limited actuator size.

Unlike single-seated control valves with a pressure balancing system, the double-seated design tolerates larger particles in the medium because it does not require any dynamic sealing elements. The flow geometry tends to flush the internal cavity, and the robust design handles abrasive or coking media noticeably better than conventional single-seated control valves.

The DUALVENT can be supplied with classic parabolic plugs, with cage plugs (for noise reduction and cavitation control), and as a multi-stage trim. Multi-stage trims divide the pressure reduction into several controlled steps, effectively avoiding cavitation and the associated shock waves, erosion damage to body and trim and noise emissions.

By design, double-seated valves typically reach Class III per IEC 60534-4 (0.1 % of Kvs) and in optimized execution also Class IV (0.01 % of Kvs). Although in special designs leakage rate Class VI can be realized, for higher shut-off classes our single-seated control valves (e.g. ECOTROL®) are the recommended alternative. DUALVENT is deliberately designed for ruggedness and low actuator thrust rather than for bubble-tight shut-off as standard.

The body is supplied – depending on the duty – in cast steel (1.0619 / A216 WCB), stainless steel (1.4408 / A351 CF8M), creep-resistant steel (1.7357 / A217 WC6), or low-temperature cast steel (1.6220 / A352 LCB/LCC). Trim materials include hardened stainless steels, stellited sealing edges or special alloys for abrasive media.

For abrasive duty, seating surfaces can be stellited or the whole plug contour fully stellited; alternatively, hardened materials such as 1.4112 or special grades are available. The alternative multi-stage cage-plug design distributes the flow energy over many small jets, so that local cavitation or erosion peaks are avoided and service life is significantly extended.

Because DUALVENT is pressure-balanced and thus thrust-relieved, smaller actuators are sufficient even for large valves: pneumatic multi-spring actuators (Series 812 ARCAPAQ®), single-spring actuators (811 UV), or piston actuators (812 DWK / 814). Electric and electro-hydraulic actuators are available as an option. Sizing is performed application-specifically with ARCA-VENA.

DUALVENT is an established workhorse in the steel industry: as a flow control element in rolling-mill cooling and laminar cooling, in mould-cooling and continuous-casting spray nozzles, in anti-surge loops of large compressors and blowers, in blast-furnace auxiliaries, and in water and steam circuits – wherever high flow rates, dirty media, and easy maintenance are required.

DUALVENT is designed in accordance with the Pressure Equipment Directive 2014/68/EU; the body is engineered to EN 12516-2 / ASME B16.34. Optional designs to AD 2000, NACE MR0175 and TA-Luft are available. The full ARCA service portfolio (ARCAlaunch, ARCAcare, ARCAsafe, ARCA24/7) is in place; sizing is performed with ARCA-VENA, and all documents are available via QR code through ARCAonsite directly at the valve.