阀杆轴心同时偏离碟片中心及本体中心，且阀座回转轴线与阀体通道轴线有一定角度的，称为三偏心蝶阀，这种设计使得蝶板启闭时几乎零摩擦，大大延长密封副的使用寿命。

A three eccentric butterfly valve is a type of valve in which the valve stem axis deviates from both the center of the disc and the center of the body, and the valve seat rotation axis has a certain angle with the valve body channel axis. This design ensures almost zero friction when the butterfly plate is opened and closed, greatly extending the service life of the sealing pair.