Zero-leakage Double Offset Butterfly valve

The zero-leakage double offset butterfly valve is a flow control device designed for industrial pipelines that require extremely tight sealing. With its double-eccentric structure and high-performance sealing technology, the valve achieves zero leakage, making it ideal for applications in petroleum, chemical, power generation, and metallurgical industries where leak prevention is critical.

Core Structure and Sealing Principle
The valve features a double-eccentric design: the stem axis is offset from both the disc center and the valve body centerline. During operation, the disc initially disengages from the seat along the eccentric offset, significantly reducing friction and wear between the disc and seat. When closing, the disc compresses against the seat under the eccentric torque, creating a tight, forceful seal. Valve seats can be made of metal hard seals (tungsten carbide, stainless steel alloys) or high-performance soft seals (PTFE, fluororubber), complemented by fire-safe and anti-static designs to meet the sealing requirements of various media.

Key Advantages for Zero Leakage

• Exceptional Sealing Performance: Meets ISO 15848-1 Class A zero-leakage standard. The bi-directional seal prevents leakage of high-pressure and corrosive media, suitable for toxic, flammable, or explosive substances.

• Wear and Corrosion Resistance: Metal hard seals operate between -40°C and 600°C, with pressure ratings Class 150–2500. Soft seals are suitable for highly corrosive media. Disc surface hardening protects against erosion from particulate-laden fluids.

• Ease of Operation: The double-eccentric design significantly reduces operating torque—30%–50% lower than standard centerline butterfly valves of the same size. The valve supports manual, pneumatic, and electric actuation, enabling automated remote control and emergency shutdown.

• Low Maintenance: Modular seat design allows online replacement of wear parts without removing the valve from the pipeline, minimizing downtime and reducing operating costs.

Typical Applications
Zero-leakage double-eccentric valves are used in long-distance oil and gas pipelines for emergency shut-off, chemical reactor medium isolation, steam pipeline control in thermal power plants, and blast furnace gas transport in metallurgical plants. Their zero-leakage capability and high reliability make them critical components for ensuring the safe and efficient operation of industrial systems.