Triple offset butterfly valve

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