Butterfly valve triple offset - S98/3 | Alfa Europe | Philippopoulos s.a.
Butterfly valve triple offset - S98/3 | Alfa Europe | Philippopoulos s.a.

Butterfly valve triple offset - S98/3 | Alfa Europe

Triple Offset Butterfly Valve Alfa Europe S98/3

The S98/3 is a triple offset, double flanged butterfly valve designed for flow isolation in pipelines requiring flanged bodies, high-temperature resistance, and minimal friction between the disc and seat. The product page specifies DN50–DN1200, double flanged connection, flanges DIN PN10/PN16 and ANSI 150#, temperature range -196 to +800 °C, and face-to-face dimensions according to ISO 5752 / API 609.

Triple Offset Technical Logic

Triple offset design is utilized when concentric valves with elastomeric liners are insufficient due to temperature, pressure, or operational cycles. The disc moves away from the seat upon opening, reducing friction and wear on sealing surfaces.

Pressure Classes and Torques

The S98/3 technical sheet provides dimension and torque tables for:

  • 150# / PN10 / PN16 / PN25
  • 300# / PN40
  • 600# / PN64

Torques increase significantly with higher pressure classes; for example, at DN600, 8,400 Nm for 150#/PN10/16/25, 18,000 Nm for 300#/PN40, and 44,799 Nm for 600#/PN64. This directly affects the selection of reducers or actuators.

Applications

Suitable for steam, thermal circuits, hydrocarbons, industrial gases, chemical lines, and processes with high or low temperatures. Final selection should be based on DN, pressure class, ΔP, design temperature, leakage requirement, body/disc/seat material, and actuator torque.

S98/3 vs. S96/3 and S97/3

  • S96/3: wafer.
  • S97/3: lug.
  • S98/3: double flanged, suitable when full flanged connection and defined face-to-face are required.

FAQ

Is it suitable for throttling?
It can be used for throttling only after checking Kv/Cv, ΔP, noise, cavitation, and thermal expansion.

What determines the actuator?
Closing torque, pressure class, DN, medium, temperature, and required safety factor.

Datasheet and documents

Description

Range: Size DN50 – DN1200

End connection: Double Flanged

Flange connection: flanges DIN PN10/PN16 & ANSI 150#

Temperature range: -196° to +800 °C

Face to face: according ISO 5752, API609

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