Triple Eccentric Wafer Butterfly Valve – Metal Sealed

The triple offset wafer type metal seated butterfly valve is a high-performance metal-sealed butterfly valve featuring a triple eccentric design. The stem centerline is offset axially from the disc sealing face, offset radially from the pipe centerline, and the sealing face centerline forms an angular deviation from the valve centerline — these three offsets work together to allow the disc to disengage from the seat instantly upon opening, eliminating friction and wear between sealing surfaces and achieving friction-free operation.

Working Principle of Metal Seated Triple Offset Wafer Butterfly Valve:
The triple offset butterfly valve is opened and closed by the stem driving the disc to rotate, typically through a 90° angular stroke.

Opening Process:The actuator drives the stem to rotate. Under the combined effect of the three offsets, the disc sealing surface disengages rapidly from the seat sealing surface. During rotation, there is virtually no contact or friction between the sealing pair until the disc becomes parallel with the pipeline direction, achieving the fully open position.

Closing Process:As the disc rotates in the reverse direction and approaches the closed position, the disc sealing surface gradually moves toward the seat. At the final moment of closure, the disc sealing surface wedges into the seat sealing surface in a conical manner, generating a mechanical wedging effect that forms a tight metal-to-metal seal. The higher the medium pressure, the tighter the sealing surfaces are pressed together, resulting in more reliable sealing performance.