Zeron Fastners
Industrial Valves & FastenersDouble Eccentric Butterfly Valves
Double Eccentric Butterfly Valves (Double Offset High-Performance Butterfly Valves) are engineered with two structural offsets: first, the stem axis is offset from the center plane of the valve seat, and second, the stem axis is offset from the longitudinal pipe centerline. This dual-offset geometry causes the valve disc to lift immediately away from the body seat upon opening, virtually eliminating seat friction, rubbing wear, and torque spikes throughout 90 degrees of travel.
Zeron Fastners manufactures API 609 Category B Double Eccentric Butterfly Valves in sizes 2" to 48" in Class 150# and Class 300#. Fabricated in Carbon Steel (WCB) and Stainless Steel (CF8M) with resilient PTFE/RPTFE soft seats or fire-safe metal-to-metal seats. Engineered for chemical process lines, district cooling plants, power steam loops, and refinery manifolds.
Technical Specifications
| Specification Feature | Details & Standard Compliance |
|---|---|
| Design Standards | API 609 Category B, ASME B16.34, BS EN 593, ISO 10631 |
| Size Range | 2" to 48" (DN50 - DN1200) |
| Pressure Ratings | Class 150#, Class 300# (PN20 to PN50) |
| Body Styles | Wafer Flangeless, Lugged Pattern, and Double Flanged Bodies |
| Body Materials | ASTM A216 WCB, A352 LCC, A351 CF8M, CF3M, Duplex 2205 |
| Seat Options | Virgin PTFE, Reinforced RPTFE, PEEK, Inconel Laminated Metal Seat |
| Stem Design | High-Strength 17-4PH / Duplex One-Piece Blowout Proof Stem |
| Fire-Safe Standards | API 607 7th Edition / ISO 10497 Fire-Safe Certified |
| Testing Standard | API 598, ISO 5208 (Bi-directional Bubble Tight Rate A) |
Double Offset Advantages
| Type & Model | Key Features & Operating Applications |
|---|---|
| Hydrocarbon Refinery Service | Bi-directional bubble-tight shutoff on flammable hydrocarbon feed lines. |
| Low Pressure Steam Headers | Withstands saturated steam up to 230°C without elastomer degradation. |
| Chilled Water HVAC Central Rings | Low operating torque allows smaller, energy-efficient automated actuator packages. |
| Fire-Safe Metal Seated Valves | Secondary Inconel metallic seal engages during catastrophic fire events. |
