Double Eccentric High‑Performance Flanged Butterfly Valve, also referred to as Double Offset Flanged Butterfly Valve, is an industrial butterfly valve adopting double‑offset geometry and flanged connection.
The stem axis is designed with double offsets relative to both the valve body centerline and the disc sealing centerline. This enables the disc to lift off the seat rapidly during opening and closing cycles, substantially reducing friction and wear between sealing faces. It further lowers operating torque and improves sealing reliability as well as service life of the valve. Featuring excellent mechanical strength and stable pipeline connection, the flanged construction is suitable for industrial piping systems with medium‑to‑high pressure, large nominal size and high sealing requirements.
Working Principle of Double‑Offset High‑Performance Flanged Butterfly Valve：
Opening Stroke: The actuator drives the valve stem to rotate, and the disc gradually turns from the closed position to the open position. Thanks to the double‑offset geometry, the disc lifts off the seat rapidly at the initial opening stage, eliminating continuous rubbing on sealing faces throughout the full rotation travel as seen in conventional butterfly valves. As the disc keeps rotating, the flow passage opens progressively. When the disc rotates to approximately 90° fully‑open position, it is substantially parallel to the medium flow direction, delivering maximum flow area and low pipeline pressure loss.
Closing Stroke: The actuator rotates the valve stem in reverse direction, and the disc turns towards the closed position. As the disc approaches the closed position, the double‑offset structure brings the disc sealing surface gradually against the seat and generates the required sealing specific pressure. Upon full closure of the disc, reliable contact is established between sealing faces to cut off medium flow and realize shut‑off and isolation of the piping system.
Manual butterfly valves are widely used in industrial piping systems for fast and reliable flow isolation and regulation. Key parameters including working temperature, medium, pressure rating, valve size and connection standard should be confirmed before ordering for proper valve selection. Customized valve sizes, pressure ratings, connection types, sealing materials and body materials are available for diverse industrial and non-standard applications. (Unit: mm)
| NPS | NPS | Type/Class | Part No | A | B | C | L | H | P | J | K | M | F | K | N-W | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 80 | 3″ | D342-150LB | D342P150XLX3 | 73 | 121 | 93 | 114 | 82 | 11.2 | 125.4 | 22.4 | M10 | 190 | 152.4 | 4-φ19 | |
| 100 | 4″ | D342-150LB | D342P150XLX4 | 96 | 133.3 | 110 | 127 | 82 | 11.2 | 125.4 | 22.4 | M10 | 230 | 190.5 | 8-φ19 | |
| 125 | 5″ | D342-150LB | D342P150XLX5 | 111 | 135 | 120 | 140 | 82 | 11.2 | 125.4 | 22.4 | M10 | 255 | 215.9 | 8-φ22 | |
| 150 | 6″ | D342-150LB | D342P150XLX6 | 142 | 152.4 | 143 | 140 | 82 | 14 | 125.4 | 22.4 | M10 | 280 | 241.3 | 8-φ22 | |
| 200 | 8″ | D342-150LB | D342P150XLX8 | 188 | 187.3 | 172 | 152 | 82 | 15.9 | 125.4 | 22.4 | M10 | 345 | 298.5 | 8-φ22 | |
| 250 | 10″ | D342-150LB | D342P150XLX10 | 236 | 231.8 | 202 | 168 | 97 | 20.6 | 142.7 | 37.3 | M12 | 405 | 362 | 12-φ26 | |
| 300 | 12″ | D342-150LB | D342P150XLX12 | 282 | 260.3 | 241.3 | 178 | 97 | 23.8 | 142.7 | 37.3 | M12 | 485 | 431.8 | 12-φ26 | |
| 350 | 14″ | D342-150LB | D342P150XLX14 | 314 | 315 | 295 | 190 | 105 | 28.7 | 142.7 | 37.3 | M16 | 535 | 476.3 | 12-φ29 |
Depending on different working conditions, resilient seal, high‑performance soft seal or metal seal configurations are available. The valve can be operated with handwheel, gear operator, pneumatic actuator or electric actuator.
Double‑offset high‑performance flanged butterfly valves are widely used in oil, natural gas, chemical, power, metallurgy, water treatment, heating, HVAC and general industrial piping systems. They are suitable for water, air, natural gas, oil products, steam and other industrial media compatible with valve materials.
