Double-offset flanged butterfly valves — resilient-seated, tight in both flow directions — in three series for different performance requirements. The H-Series delivers maximum energy efficiency with a patented hydrodynamic disk, reducing flow resistance by up to 59% compared to conventional butterfly valves. The M-Series provides proven reliability with automatic sealing system for medium requirements. The S-Series is purpose-built for hydropower with optimised zeta value and stainless steel sealing seat. All series feature medium-free bearing (dry shaft), maintenance-free bushing, and wear-resistant weld overlay seat.
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▸ Key Features
Common to All EKN® Series
- Double-offset disk bearing mounted in maintenance-free bushing
- Medium-free bearing (dry shaft) via double O-ring sealing and closed disk eyes
- Wear-resistant, corrosion-resistant and undermining-resistant seat with weld overlay
- Profile sealing ring replaceable without disassembling the disk
- Tight in both flow directions acc. to EN 12266, leak rate A
- Self-locking, fully enclosed, maintenance-free worm gear with mechanical position indicator
EKN® H-Series — Maximum Performance
- Patented hydrodynamic disk with enlarged inner diameter — reduces flow resistance by up to 59%
- Patented pressure compensation channels — minimise pressure losses and turbulences in the outlet area
- Reduced risk of cavitation damage at increased flow velocities
- Highly laminar flow allows significantly reduced distance to downstream installations
- Wedge pin connection for permanently backlash-free shaft-to-disk connection
- Bronze bearing with double O-ring sealing — bearing 100% protected from medium
EKN® M-Series — Medium Requirements
- Automatic sealing system with enclosed and pressure-supported profile sealing ring
- Resists high gap velocities — flow-independent operation
- Fully encapsulated bearing for enhanced corrosion protection
- Available in hot water versions (MT up to 150°C / MTG up to 200°C with aluminium-bronze coating and PTFE compound seal)
- Also available rubber-lined for aggressive media
EKN® S-Series — Hydro Power Design
- Optimised zeta value for minimum flow resistance
- Stainless steel sealing seat
- Fully encapsulated bearings with pressure-assisted seals
- Designed for high flow rates and sandy water
▸ Technical Specifications
| Parameter | EKN® H | EKN® M | EKN® S |
|---|---|---|---|
| Positioning | Maximum performance | Medium requirements | Hydro power design |
| Nominal diameters | DN 150 – 3000 | DN 150 – 3000 | — |
| Nominal pressure | PN 10 / 16 / 25 | PN 10 / 16 / 25 | — |
| Face-to-face length | EN 558, series 14 (F4) | EN 558, series 14 (F4); also series 13 (F16 short) | — |
| Flanges | EN 1092-2 | EN 1092-2 (EN 1092-1 for hot water) | — |
| Sealing standard | Resilient-seated acc. to EN 593 | Resilient-seated acc. to EN 593 | — |
| Leak-tightness | EN 12266, leak rate A — both directions | EN 12266, leak rate A — both directions | — |
▸ Available Variants
▸ Coatings and Body Options
- Epoxy coated acc. to GSK guidelines — standard for water applications
- Rubber-lined — for aggressive media (acids, alkaline solutions, abrasive media)
- Aluminium-bronze (AL-bronze) coated — for hot water up to 150°C (MT) or 200°C (MTG)
- Cast iron body (DN 150 – 1200) or welded steel body (DN 1300 – 3000 and custom sizes)
▸ Applications
- Water treatment and water distribution
- Pretreated wastewater
- Dams and hydropower (including turbine inlet valves)
- Power plants and district heating (hot water versions)
- Industry — process water, cooling circuits, aggressive media
- Pressure management