Operating principle

Triple Eccentric Butterfly Valves

A triple eccentric butterfly valve is a quarter-turn valve designed for reliable isolation and control of liquids, gases, and steam in demanding process conditions. Like all butterfly valves, it operates by rotating a disc within the pipeline. However, unlike centric or double-eccentric designs, the triple eccentric geometry ensures that the disc and seat only come into contact at the final moment of closing. This cam-like sealing action eliminates friction, reduces wear, and significantly extends service life.

Illustration of a triple butterfly valve

Offset 1

The valve shaft is offset from the seating surface to maintain continuous contact geometry between the seal ring and the seat.

Offset 2

The shaft is positioned eccentrically relative to the pipe centerline, allowing the seal ring to shift from the seat during rotation.

Offset 3

The seat is manufactured with a conical geometry, with the cone axis inclined relative to the pipe centerline. This design prevents any rubbing between the sealing surfaces, ensuring friction-free operation.

Advantages

Compared to gate, globe, or ball valves in larger diameters, triple eccentric butterfly valves offer a more compact and lightweight solution, reducing installation space, structural support requirements, and overall costs.

Triple eccentric butterfly valves are ideal for medium- to high-pressure systems and extreme temperature applications where tight shut-off, fire safety, resistance to thermal cycling, and long-term durability are essential. They are commonly actuated with gearboxes or by pneumatic, electric, or hydraulic actuators and can be designed to provide uni-directional or bi-directional sealing, depending on application requirements.

Their combination of compact design, zero-leakage capability and suitability for demanding services makes them a preferred choice in industries such as oil and gas, power generation, chemical processing, and cryogenic applications.