用镁带组合阳极防止三层PE防护层埋地钢管"过保护"

对于近年开始广泛应用的三层PE防护层埋地钢质管道,在应用传统的锭状镁阳极实施阴极保护时,常常出现“过保护“现象。针对这一情况,我们研究开发了镁带组合阳极新技术。把多根挤压带状镁阳极平行安装在布满筛孔的塑料管内,四周装填包料,每根镁带用独立的电缆引出,管外缠绕棉布。跟相等重量的锭状阳极相比,镁带组合阳极的工作面积增大,提高了阳极输出电流。埋设组合阳极时,每根镁带阳极的电缆引出到地面的测试桩内,在那里通过铜片跟阴极管道接通,在保护系统运行过程中根据管道实际达到的保护程度可以灵活增减连通的镁带阳极,调节阳极输出总电流。工程实践证明:这项新技术可以有效防止“过保护“,实现管道阴极保护系统安全运行。

PREVENTION OF 3-LAYER POLYETHYLENE COATED PIPES FROM OVERPROTECTION BY COMPOSITE MAGNESIUM RIBBON ANODES

"Overprotection" occurs when 3-layer polyethylene coated pipe is cathodically protected with traditional block magnesium anode.To shoot the trouble,a novel composite magnesium ribbon anode is proposed.Several extruded magnesium ribbons in parallel are placed in a perforated plastic barrel with filling material.Each ribbon has its own conducting lead.The unique anode has larger working area and greater output current than the block anode with equal weight.In installation each ribbon anode is individually connected to aboveground test station,where it links to the pipe to be protected.Thus according to the extent of protection the number of working ribbon anodes could be varied and the anode output current could be adjusted.Practical engineering projects proved the new technique is successful in prevention from overprotection.