DUALVENT
Double-seated valve250 / 280
DUALVENT is a double-seated valve that is used for more severe applications.
Details
- Series 250 / 280
- DN 50–350 / DN 40–250
- PN 10–40 / PN 63–160
- Temperature range -10 °C to 530 °C
DUALVENT is a double-seated valve that is used for more severe applications. The double-seated trim regulates the medium at two throttle points. The two control plug diameters are matched to each other in such a way that the medium has an opening influence on one control plug and a closing influence on the other control plug, and the actuating forces thus are minimized. Thanks to the variety in the choice of materials, the connection to the piping system or the versatile trims, the control valve can be precisely aligned to your process and the dirty medium. This also applies to the shaping of the control plugs. The option of a multi-stage, double-seated trim also avoids cavitation that could lead to shock waves and erosion damage to the valve body and internal parts. You are on the safe side with the DUALVENT control valve, even with tough applications. Of course, our complete actuator and controller program is available for the actuating of the double-seated valves.
This is what distinguishes DUALVENT double-seated valves:
- Multifunctional positioner
- Flexibility thanks to ARCA modular system
- Robust precision trims
- Pressure and thus force balanced
- Very low actuating force
- High functional reliability even under adverse operating conditions
Product inquiry
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Double-seated valve with parabolic plug
With this control valve, the medium is distributed to two parabolic plugs and regulated. The proven double-guided parabolic plug design is often used in water applications and impresses with its design, which is both robust and simple. Due to the design, the outer diameters of the two parabolic plugs are almost the same and thus almost pressure-balanced. For the actuating force dimensioning, therefore, not the full plug diameter, but only the resulting annular gap needs to be taken into account and you can manage your control task with smaller actuators.
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Double-seated valve with perforated plug
As with all ARCA series, the ARCA DUALVENT is also designed using the modular principle in a variety of designs. The double-seated valve offers possibilities up to the nominal pressure PN 160 and covers the temperature range up to 530 °C. Here we have a double-seated control valve in the high-pressure version with cooling fin bonnet, so that the stuffing box packing is located outside the hot area. For control, perforated plugs are chosen instead of the usual parabolic plugs in order to counteract noise generation. Of course, small actuators are also specified here in order to be able to control high differential pressures.
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Double-seated valve, multi-stage
For higher differential pressures and applications where the cleanliness of the medium cannot necessarily be guaranteed, the ARCA DUALVENT offers the possibility of multi-stage pressure reduction. With this version it is possible, for example, to reduce the medium pressure without cavitation. Due to the design of the double-seated valve, pressure balancing, which tends to stick even with slightly contaminated fluids, is not required. The selection of small actuators is a matter of course for the double-seated control valves.
Frequently Asked Questions – DUALVENT double-seated valve
What sets the DUALVENT double-seated control valve apart?
The DUALVENT double-seated control valve is a rugged control valve with two seat-plug pairs on a single stem. The two plug diameters are matched so that the flow forces on one plug act in the flow-to-close direction while the other acts in the flow-to-open direction, almost balancing each other. The result is exceptionally low net actuator thrust – allowing large flow rates and high differential pressures to be handled with a relatively small actuator.
Which sizes and pressure ratings does DUALVENT offer?
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.
How does the force balancing of the double-seated valve work?
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.
Which applications is DUALVENT particularly suited for?
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.
Why is DUALVENT suited for dirty media?
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.
Which plug shapes are available for DUALVENT?
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.
Which seat leakage class does the double-seated valve meet?
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). In special soft-seated designs, Class VI leakage can be achieved – the elasticity of the soft seat compensates for the tolerances. As standard, DUALVENT is deliberately designed for ruggedness and low actuator thrust rather than for bubble-tight shut-off; where consistently tight shut-off is required, our single-seated control valves (e.g. ECOTROL®) are the recommended alternative.
Which materials are available for body and trim?
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.
How is the trim protected against 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.
Which actuators are used?
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.
What are typical DUALVENT applications in the steel industry?
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.
Which service offerings, standards and directives are available?
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.
