Electric Flanged Butterfly Valves

Concentric Resilient-Seated Series

Designed for clean water, raw sewage, and HVAC circulation loops (PN10/PN16). Features bonded or vulcanized EPDM or NBR rubber liners with polished 316 stainless steel or aluminum-bronze discs, providing bubble-tight bidirectional Class VI shut-off with low head loss.

• Double-flanged short (EN 558 Series 13) or long (Series 14) patterns
• Ductile iron (GGG40/GGG50) body with fusion-bonded epoxy coating
• Dead-end service rated up to full working pressure without downstream flange

High-Performance Double/Triple Eccentric Series

Engineered for high-pressure industrial utilities, district heating, and chemical steam (Class 150/300 / PN25/PN40). Off-center disc geometry lifts the disc cleanly off the seat upon opening, virtually eliminating seat friction, mechanical wear, and operating torque spikes.

• Metal-to-metal Stellite or laminated stainless/graphite seating
• Zero seat rubbing ensures extended operating lifespan exceeding 100,000 cycles
• Handles high differential pressures and operating temperatures up to 350°C

Full Dead-End Pipeline Isolation

Because each flange bolts independently to adjacent pipe flanges, downstream piping can be disassembled for maintenance or pump replacement while the valve maintains bubble-tight upstream pressure containment.

Rigid Anti-Deflection Casting

In large pipelines (DN300+), wafer valves can suffer body distortion under ground subsidence or piping thermal expansion. Our thick double-flanged ductile iron body absorbs bending loads without seat distortion.

Hydrodynamic Low-Head-Loss Disc

The streamlined lens-profile disc minimizes fluid turbulence and cavitation. In fully open position, it provides maximum flow capacity (Cv) and remarkably low pumping head loss, lowering plant energy consumption.

High-Torque Industrial Actuation

Paired with heavy-duty electric actuators delivering up to 4,000 Nm. Features secondary worm gear reduction, dual travel limit switches, mechanical torque sensors, and manual override handwheels for fail-safe field operation.

Fusion-Bonded Epoxy (FBE) Coating

Body castings receive electrostatic high-adhesion fusion-bonded epoxy coating (thickness ≥ 250 µm). Completely isolates the cast iron from aggressive groundwater, potable water chloramines, and outdoor atmospheric corrosion.

Multi-Standard Flange Drilling

Flange bolt patterns are CNC drilled strictly to ASME B16.5 / B16.47 (Class 150), EN 1092-2 (PN10/PN16/PN25), or AWWA C207 standards, ensuring seamless compatibility across domestic and international civil engineering projects.

1. What is the operational advantage of a double-flanged butterfly valve over a wafer valve?

Wafer valves are clamped between two pipe flanges with long through-studs. If pipeline thermal stresses or soil settlement occur, long studs can stretch, causing gasket blowouts. Furthermore, wafer valves cannot be used for "dead-end" service. Double-flanged butterfly valves bolt directly and independently to each pipe flange, providing complete structural stability, precise centering, and allowing downstream pipe maintenance while the valve isolates upstream pressure.

2. What is the difference between EN 558 Series 13 (Short) and Series 14 (Long) patterns?

Both are standardized face-to-face dimensions for double-flanged butterfly valves:

• Series 13 (Short Pattern): More compact and lightweight; standard for municipal water treatment and tight pump stations.

• Series 14 (Long Pattern): Replicates the traditional face-to-face length of older gate valves, making it the perfect direct drop-in replacement for retrofitting heavy gate valves with automated butterfly valves without altering pipe lengths.

3. Why should high-performance double-eccentric valves be chosen for high-cycle lines?

In standard concentric butterfly valves, the rubber seat rubs continuously against the disc edge throughout the entire 90° stroke, causing friction and seat wear. In double-eccentric valves, the shaft is offset from the valve center and pipe axis. As rotation begins, the disc cams away from the seat immediately, contacting the seat only during the final degrees of closure. This eliminates seat galling, lowers operating torque, and extends service life beyond 100,000 cycles.

4. How are large-diameter electric actuators sized to prevent water hammer?

Fast closing of large-diameter butterfly valves (DN600+) can trigger severe acoustic pressure surges (water hammer) that rupture civil pipelines. DELCO pairs large flanged valves with electric actuators equipped with multi-stage planetary and worm gearboxes engineered for controlled operating speeds (typically 40 to 90 seconds for full 90° travel), ensuring smooth, surge-free closure.