亚洲少妇18久久久久久久-国产亚洲欧美日韩欧美日韩欧美-欧美日韩三级一区-日韩免费成人在线-欧美成人看片一区二区-久,久久久久久97-天天日天天干天天舔天天操天天射-91人视频在线观看-欧美人妻3p一区二区三,av久久色中文字幕,日韩激情另类在线观看,97久久草精品视频

閥桿軸心同時偏離碟片中心及本體中心，且閥座回轉(zhuǎn)軸線與閥體通道軸線有一定角度的，稱為三偏心蝶閥，這種設(shè)計(jì)使得蝶板啟閉時幾乎零摩擦，大大延長密封副的使用壽命。

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.