国标双偏心蝶阀

⊙高性能蝶阀（对夹式）High performance butterfly valve （Wafe）                           

一般的高性能蝶阀为单偏心或双偏心结构。双偏心结构是在设计时将阀轴偏离密封面中心线，轴稍稍离管路中心线，形成第二偏心，偏心的目的在于使蝶板开至大约20°之后，阀座与密封圈之间脱离，从而减少摩擦。

Generally，high performance butterfly valves are sing le eccentric or double eccentric，As to double eccentric structure，valve shaft is designed deviated from the centerline of sealing face to form up the first eccentric，and slightly deviated from the centerline of pipe to form up the second eccentric，the eccentrics are to make seat disengaged from sealing ring to lower the friction when disc is opened to approximay20°.

软密封阀座选用丁「E、尸丁「三、R丁F氢薪火结构符合“尸1607的火锹验， 在发生灾时具有密封能力。

硬密共精构具有本质的防火能力，可保持双向无泄漏。可在不拆蝶板、阀杆的情况下更换阀座，上下阀杆处没有低摩擦系数的轴套，减少了阀门启闭时阀杆的摩擦力。

双偏心的设计结构，减小了开启频繁时密封副上下两端的磨损。阀门与驱动装置接口符合ISO5211，产品质量严格按I S05211进行控制。

Soft Seal Seat， made of TFE, PTFE or RTFE, fireproof constr一uction conforming to AP1607 fire test, provided with sealing Property in case of fire.

Hard seal structure is provided with intrinsical fireproof property. Two way leak一proof seal. Seat replaced with no need to take off disc and stem the upper and lower stems provided with low friction sleeves to lower the frictional force of stem when valve is opened or closed.

Double eccentric structure to lower the abrasion at the upper and lower ends of seal in case of frequent open and close. The interface between valve and drive unit conforms to ISO5211.Product qua一lity is under rigorous control according to ISO9001.

⊙阀座密封原理 Principle of Seat Sealing

1、   蝶板处于关闭状态，介质从阀座上游进入，在介质力的作用下，密封圈紧贴蝶板密封面，由于密封圈的弹性和变形作用，保证密封副的密封。

2、   蝶板处于关闭状态，介质由阀座下游进入，在压板上挤压下，密封圈克服介质的作用力，紧贴蝶板密封面，焦证密封副的密封。

1. Disc closed, medium enters from the upstream of seat. Under the force of medium, sealing ring will get close to the sealing face                      of disc, and the elasticity and deformation of sealing ring will function to guarantee the performance.

2. Disc closed, medium enters from the downstream of seat. Under the extrusion of press board ring sealing will overcome the acting force of medium and get close to the sealing face of disc, thus to guarantee the sealing performance.