Butterfly valve triple offset - S97/3 | Alfa Europe | Philippopoulos s.a.
Butterfly valve triple offset - S97/3 | Alfa Europe | Philippopoulos s.a.

Butterfly valve triple offset - S97/3 | Alfa Europe

Alfa Europe S97/3 Triple Offset Butterfly Valve

The S97/3 is a triple offset, lug type butterfly valve designed for flow isolation in high-temperature industrial lines, steam, gases, hydrocarbons, and thermal processes. The lug construction is used when mechanical retention with bolts on the valve body is required, rather than simple wafer insertion.

Technical Specifications

  • Range: DN50–DN1200
  • Connection: lug type
  • Flanges: PN10 / PN16 / PN25 / PN40, ANSI Class 150 / 300
  • Face-to-face: ISO 5752 / API 609
  • Temperature: -196 to +800 °C
  • Torque tables: available for 150#–PN10/16/25, 300#–PN40 and 600#–PN64

Triple Offset Operational Logic

The triple offset design minimizes friction between the disc and seat during opening/closing. This is critical in applications where elastomeric seats are not acceptable due to temperature, pressure, chemical load, or thermal cycling.

In such services, selection is not solely based on DN and PN. The following must be checked:

  • differential pressure at closure,
  • design temperature,
  • body/disc/sealing material,
  • operating torque and actuator sizing,
  • leakage class requirements and operating cycles.

S97/3 vs S96/3

The S96/3 is a wafer version, while the S97/3 is lug. The lug configuration is preferred when better mechanical retention in piping is required or when installation demands bolting on the valve body. For end-of-line operation, permissible pressure per DN and load direction must be confirmed.

Typical Applications

  • Steam and thermal networks.
  • Petrochemical and chemical lines.
  • Industrial gases.
  • Hydrocarbons and fuels.
  • Low or high-temperature applications.

FAQ

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

What determines the actuator?
DN, pressure class, ΔP, temperature, seat design, and required safety factor in torque.

Datasheet and documents

Description

Range: Size DN50 – DN1200

End connection: Lug type

Flange connection: PN10/PN16/25/40 & ANSI 150, 300#

Temperature range: -196° to +800 °C

Face to face: according ISO 5752, API609

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