1. Definition and core structure
Single eccentric butterfly valve is a butterfly valve that optimizes sealing performance by designing the valve stem axis to deviate from the center of the butterfly plate. Its opening and closing parts are butterfly plates, which are driven by the valve stem to rotate around the axis 0°~90° to achieve medium cutting or adjustment. It is mainly used to quickly control the flow of fluid in pipeline systems.
2. Structural features
Eccentric design
The valve stem axis deviates from the geometric center of the butterfly plate (forming a single eccentric distance), so that the upper and lower ends of the butterfly plate reduce direct extrusion with the valve seat during rotation, reducing the risk of wear.
Improved from the centerline butterfly valve (the butterfly plate is concentric with the valve body), it solves the problem of easy deformation of the seal caused by repeated extrusion of the centerline butterfly valve.
Sealing structure
The sealing ring can be set on the butterfly plate or the valve body:
Butterfly plate sealing ring: The edge of the butterfly plate is embedded with elastic material (such as nitrile rubber), which is suitable for low-pressure clean media;
Valve body sealing ring: The valve seat adopts metal hard seal or composite material (such as stainless steel + flexible graphite), which is suitable for high temperature or particle-containing media.
Drive mode
Driven by a worm gear reducer or pneumatic actuator, it improves operating performance and enables the butterfly plate to be positioned at any angle.
3. Limitations
Pressure and temperature limits: Due to reliance on soft sealing materials (such as rubber), the long-term working pressure generally does not exceed PN16, and the temperature range is limited to -20℃~120℃, which is not suitable for high pressure, high temperature or highly corrosive media;
Regulation accuracy: The flow characteristics are close to the quick-open type, and the regulation linearity is weaker than that of double-eccentric or triple-eccentric butterfly valves.
4. Typical application scenarios
Municipal engineering: flow control and isolation in water supply and drainage networks;
Food and medicine: opening and closing of clean media in sanitary pipelines;
Light industry: regulation and cutoff of low-pressure steam and air systems.