The triple offset butterfly valve by Audco Italiana is an advanced fluid control solution for demanding operating conditions. It relies on a three-offset structure that ensures metal-to-metal sealing without excessive friction, extending component lifespan.
Technical Description
The triple offset butterfly valve, also called triple eccentric, features a stem offset from both the X and Y axes of the valve centerline, generating a cam-like motion during operation. Its three key offsets are: the first shifts the shaft from the bore centerline, the second from the disc/seat sealing centerline, and the third tilts the seat cone axis into an asymmetric elliptical profile. This eliminates early contact between disc and seat, minimizing wear and enabling friction-free cycling until final closure.
Unlike zero-offset valves, which rotate centrally with soft seals and constant friction, or double-offset types with partial cam action but initial/final friction, the triple offset employs a 90° cone for contact only at shutdown. This makes it superior for high-pressure or high-temperature uses, overcoming limitations of earlier designs.
These valves perform well in abrasive media, pressures over 150 psi, extreme temperatures, or fugitive emission risks, serving oil & gas, refining, chemicals, power generation, offshore, and pulp/paper sectors. They suit steam, high-temperature pure gases/liquids where uncoated metal seats provide cost-effective reliability.
Materials Table
| Element | Characteristics |
|---|---|
| Body Design | Long Pattern, Short Pattern, Top Entry, Welded Body, Flaged, Lug, Wafer, with jacket, Cryogenic with stem extension. |
| Material | Carbon Steel, Duplex, Super Duplex, Stainless Steel |
| Operating Temperature | Standard Temperature |
| Pressure Class | ASME, PN |
| Seat/Seal Type | Metal-to-Metal, removeable |
| Shutoff Class | API 598, Class IV (FCI 70-3), Class V (FCI 70-2), Class VI (FCI 70-2), Zero Leakage |
| Standards | API 609, ASME B16.34 |
| Style | Emergency Shutoff Valves, Switching Valve, Control Valve |
| Valve Size | NPS 4 / DN 100, NPS 96 / DN 2400 |
| Valve Size Standard | DN, NPS |
| Valve Type | Triple Offset Valve |
| Fugitive emissions | Improved packing to reduce fugitive emissions |
| Safety Integrity Level (SIL) | The design has an intrisecally higher SIL |
| Options | Bearing Flushing, for media like sulphur. |
Triple offset butterfly valve
Triple offset butterfly valve with jacket
Design highlights include field-replaceable seats for quick on-site maintenance without pipeline downtime, customizable body/disc/sealing materials per conditions, and ISO 5211 mounting for electric, pneumatic, hydraulic, or turbine actuators. Combined packing seals limit leakage to 20 ppm, with dynamic-load options for extended packing life.
Audco is ready to provide all the information you need to get a quick and complete quote.
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