Double Eccentric Butterfly Valves
Double eccentric butterfly valve designed for high-pressure waterworks and pipeline systems, featuring an eccentric disc-seated design with a body and disc optimized for minimal flow resistance and tight bi-directional sealing; the double offset mechanism creates a cam-like motion that quickly separates the rubber sealing ring from the body seat during initial opening, reducing operating torque, minimizing wear, and extending valve seat life, while the replaceable in-line sealing ring design allows maintenance without removing the disc, making the valve ideal for reliable isolation applications.
Design Features
Double Eccentricity: The double eccentric butterfly valve has 2 offsets. This offset is the displacement of the shaft from the centerline.
- The first offset is the displacement of the shaft from the centerline of the disc seat and body seal. This maintains continuous sealing surface during the opening and closing of the valve.
- The second offset is the displacement from the centerline of the pipe/bore. This is to allow the disc and seal right to easily lift off and away from the body seat.
Hydrodynamic Disc Design: A hydrodynamic disc design means the butterfly valve does not fight the water, instead it lets the water flow smoothly, saving energy (energy efficiency) and protecting the system.
Bi-Directional Sealing: Bi-directional butterfly valves, designed to provide tight shutoff and reliable operation in both flow directions (from either side of the valve). Or the valve can seal and operate with fluid pressure applied from either side of the disc.
Stainless Steel Body Seat: The body seat is the sealing surface inside the valve body that the disc seal presses against to achieve shutoff. The SIERRA welded stainless steel seat design provides a lower coefficient of friction during operation.
Material Standards
Body, Disc, Gland and Bottom Cover ——— Ductile Iron EN-GJS-500/7 Or Ductile Iron EN-GJS-400/12 Acc. To (EN1563)
Body Seat ——— Stainless Steel Grade 309L
Retaining Ring ——— Stainless Steel Grade 316
Disc Seal ——— EPDM Rubber
Driving Shaft & Stub Shaft ——— X20Cr13 (AISI 420)
Valve Bearing ——— Self-Lubricating Bearing (PTFE/Steel/Tin)