外浮顶储罐机械密封雷击火花放电研究

Research on Lightning Stroke Discharge of Mechanical Seal of External Floating Roof Tank

为了深入研究外浮顶储罐机械密封雷击火花放电点和火花放电电流,加工制作了机械密封雷击实验装置,采用10/350冲击电流开展了机械密封雷击火花放电实验。当机械密封的4个弹片与金属密封板绝缘,冲击电流达到2.12 k A时,密封板与罐壁接触部位、伸缩架与密封板连接处都产生了火花放电现象。当机械密封只有1个弹片与金属密封板接触,冲击电流达到0.578 k A时,弹片与金属密封板之间产生了火花放电。冲击电流达到1.09 k A时,弹片贴合处、伸缩架与密封板连接处都产生了火花放电。由此可见,当储罐遭受雷击时,机械密封存在多处放电点,严重危害着储罐的安全运行。

In order to further study the spark discharge positions and currents of the mechanical seal of external floating roof tank, we processed lightning stroke experiment device of mechanical seal. Lightning stroke experiment of mechanical seal is carried on by 10/350μs impulse current. When it is insulated between four springs and metal sealing plate and impulse current reaches 2.12kA, the spark discharge is generated at contact portion of sealing plate and tank wall, joint of retractable frame and the sealing plate. When only one spring contacts with metal sealing plate, the impact current reaches 0. 578 kA, the shrapnel and metal seal plate produced a spark discharge, and impulse current reached 1.09kA, the spark discharge is generated at contact portion of sealing plate and spring, joint of retractable frame and the sealing plate. These show that there are many discharge points on mechanical seal which seriously endanger safety of tank, when tanks struck by lightning.