Name: Butterfly valve - S57 | Alfa Europe
Brand: Alfa Europe
SKU: Butterfly valve - S57 | Alfa Europe

Butterfly Valve Wafer Alfa Europe S57

The S57 is a marine/industrial wafer-type butterfly valve with a bonded liner, designed for installation between flanges in flow isolation lines. It covers DN40–DN1200, face-to-face according to EN 558-1 Series 20, and design EN 593. Flange connections cover DIN PN6/10/16/25, ANSI B16.5 Class 150, and JIS 5K/10K.

Operating Conditions

Temperature: -40 to +250 °C, depending on seat material.
Pressure: up to 25 bar for small to medium diameters, up to 16 bar for larger sizes DN700–DN1200.
Vacuum: up to 1×10⁻³ / 0.2 Torr absolute.
Top flange ISO 5211 for manual, gearbox, or actuator operation.

Materials and Seats

Available body materials: EN-JS1030 ductile iron, ASTM A216 WCB, stainless steel 1.4408, and aluminum bronze BS 1400 AB2. Discs available in BS 1400 AB2, EN-JS1030, 1.4408, and SD 2507. Shaft options include SS 1.4122, SS 431, SS 1.4462, and SD F53.

Seat options:

NBR: -15 to +80 °C
EPDM: -23 to +120 °C
Viton: 0 to +200 °C
Silicone: -40 to +230 °C

Version Selection

Bare shaft: for pneumatic or electric actuator connection.
Lever operated: DN40–DN200, for local manual operation.
Gearbox operated: DN40–DN1000, suitable when lower operating torque is required for larger diameters.

Marine Applications

Used in auxiliary ship systems, seawater/cooling water circuits, ballast, bilge, freshwater, and low to medium pressure lines. For seawater, aluminum bronze, stainless, or duplex materials are typically considered, depending on chlorides, temperature, and exposure time.

Certifications

The product page lists marine certifications DNV, LR, ABS, and CCS.

FAQ

Is it suitable for flow regulation?
Only for limited throttling. Continuous proportional control requires cavitation, velocity, and torque assessment.

What should be checked upon procurement?
DN, PN, flange standard, body/disc material, seat, medium, temperature, differential pressure, and operation type.