Abstract: The structural style and working principle of the external floating roof tank's automatic breather valve were briefly introduced.Fixed the analogical standard of the oil vapour space between the factory end and the floating plate when it was unrisen.The volume ofthe roof tank decides the heat affecting volume calculate the tank throughtout and the breathing area of the breather valve.According to the fluid steady flow mathematical equation,deduced the height computing formula of petroleum production flowing into the automatic breather valve.Definite the design height that the valve handle must possess when the breathing area was given.And then analyze the oil spill reasons of the established oil tanks,which may be caused by the lacking of breathing area or the design height of valve handle,and the problems must pay attention to in future design.

Key words: External floating roof tank,    , Automatic ventilation valve,    , Ventilation,    , Stem height,    , Oil spill

摘要： 简要介绍了外浮顶油罐自动通气阀的结构形式和工作原理,将外浮顶罐浮盘未升起时浮盘与罐底之间的油气空间类比标准固定,顶罐容积确定热影响容积进行储罐通气量及通气阀通气面积的计算,根据流体稳定流动量方程推导出油品进入自动通气阀阀体内的高度计算公式,确定自动通气阀在通气面积一定时阀杆必须具有的设计高度,进而分析出一些已建油罐可能由于通气阀通气面积不够或阀杆设计高度不足而产生溢油的原因和今后设计应注意的问题。

关键词: 外浮顶油罐,    , 自动通气阀,    , 通气量,    , 阀杆高度,    , 溢油