High-performance double eccentric butterfly for large-bore isolation and throttling with low torque and long seat life.
The double offset (high performance) butterfly valve positions the shaft behind the disc plane and offset from the pipe centreline, creating a cam action during opening that lifts the resilient or metal seat off the liner before rotation begins. This virtually eliminates seat abrasion, extending service life dramatically compared to concentric designs and enabling the valve to achieve tight shut-off over thousands of cycles.
VALVAX double offset butterfly valves are designed to API 609 Category B and are available in wafer, lug, and double-flanged body styles. The lug body enables use as a line-end valve. Metal-seated versions are suitable for high-temperature steam, hot gases, and abrasive slurry service where resilient seats would fail.
| Parameter | Value |
|---|---|
| Design Standard | API 609 Category B |
| Size Range | 2″ – 24″ (DN50 – DN600) |
| Pressure Class | ASME Class 150 – 600 |
| Face to Face | API 609 / ASME B16.10 |
| End Connections | Wafer / Lug / Double-Flanged |
| Body Material | WCB / CF8M / WC6 / Duplex |
| Disc Material | SS316 / CF8M / Duplex / Alloy 625 |
| Seat Material | EPDM / Viton / PTFE / Metal-to-Metal |
| Design Temp. | -46°C to +400°C (resilient) / +650°C (metal) |
| Testing | API 598 |
| Fire Safe | API 607 on request |
ASTM A216 WCB
General service for water, steam up to 300°C, and hydrocarbon streams in standard environments.
ASTM A217 WC6
High-temperature steam and hot gas service in power plants and refineries up to 593°C.
ASTM A351 CF8M
Corrosive chemical media, seawater cooling systems, and pharmaceutical process lines.
ASTM A890 4A / 5A
Offshore topside, desalination, and aggressive chemical environments requiring maximum corrosion resistance.
Large-bore isolation and flow regulation in water treatment plants, dams, and distribution mains.
Terminal and refinery block and throttle service in large pipe sizes where ball valves are uneconomical.
Cooling water isolation, condenser inlet, and steam bypass regulation in thermal power plants.
Large-bore acid, caustic, and solvent line isolation in CF8M or duplex body with PTFE seat.
Sea chest valves, ballast water isolation, and pump discharge in duplex or naval bronze.
Our engineers will select the optimal body style, disc, and seat material for your flow conditions.