Double Eccentric Butterfly Valve

The Concentric butterfly valve is an industrial valve used for the on-off and flow control of pipeline systems. It is widely applied in fields such as petroleum, chemical industry, metallurgy, and hydropower. Its core structural feature is that the axis of the valve stem, the center of the butterfly plate, and the center of the body are on the same axis, featuring simple manufacturing and balanced opening and closing torque. By selecting different materials for the valve plate, valve stem, and sealing seat, it can be adapted to various different working environments, such as desulfurization, vacuum, and seawater desalination systems.

Designed specifically for industrial ventilation and gas transportation systems, it features a high-strength carbon steel or stainless steel valve body, equipped with a low-torque sealing structure, enabling efficient regulation of large flow of gas media. The optimized butterfly plate design is combined with wear-resistant sealing rings, ensuring reliable performance under harsh conditions such as high temperatures and dust. It is suitable for ventilation and dust removal systems in industries such as power plants, metallurgy, and chemical engineering

The working principle of the three eccentric butterfly valve is based on its unique structural design, which achieves sealing and flow control functions through three eccentric distances: ‌Structural Design: ‌Three Eccentric Structure‌: The valve stem axis deviates from the center of the butterfly plate and the body center, and the rotation axis of the valve seat is at an angle to the axis of the valve body channel. This design enables the butterfly plate to form a wedge-shaped space with the valve seat when closed, achieving sealing through friction.‌ ‌Conical Sealing Surface‌: The periphery of the butterfly plate is machined into an external inclined conical surface, and the valve seat is an internal inclined conical surface, forming an elliptical contact surface. When closed, the butterfly plate achieves sealing through the asymmetric pressing force in the up and down directions, and the sealing becomes tighter as the pressure increases.‌ Working Mechanism: ‌Open State‌: The butterfly plate is separated from the valve seat, and the fluid passes through the channel; due to the eccentric design, during the opening process, the butterfly plate gradually detaches from the valve seat, reducing friction and operating torque.‌ ‌Closed State‌: The butterfly plate rotates 90° to contact the valve seat, forming a wedge-shaped space and achieving sealing through torque. ‌Flow Regulation‌: During the opening rotation of the butterfly plate, the valve's flow area gradually increases, reducing fluid resistance and improving the flow coefficient, achieving flow regulation. ‌Technical Advantages‌: Sealing Performance‌: The metal-to-metal hard sealing method can still maintain good sealing performance in high-temperature and high-pressure environments;‌ ‌Low Friction Operation‌: The eccentric design significantly reduces the operating torque and extends the valve's lifespan;‌ ‌Self-Locking Function‌: When closed, the butterfly plate becomes tighter under pressure, preventing the phenomenon of over-positioning.‌ This valve is widely used in the petroleum, chemical, and power industries, and common structural connection forms include double flange type, welding type, lug type, and socket type, etc.