清管器测径板与U型管道中弯头撞击分析

Analysis of the Strike Between Gauging Pig and the Elbows of U-Shaped Pipeline

测径清管器经过U型管道时,若测径清管器设计不合理或者清管器运动速度过大,清管器测径板易与弯头相撞,导致测径板变形,从而误以为管道上存在变形。为解决该技术难题,结合一种具体测径清管器,通过分析该测径清管器经过U型管道弯头时的运动特性和测径清管器及弯头的几何特性。得出结论:当测径清管器的运动速度超过一个极限速度时,清管器经过弯头时所受离心力大于清管器支撑板的屈服极限,引起前支撑板屈服,此时测径板可能与弯管内壁外弧侧相撞,同时还得到影响此极限速度值大小的多种因素。另外,发现测径板、支撑板、弯头曲率半径满足一定的几何特性关系时,清管器测径板将与弯管内壁内弧侧撞击。利用得到的这些分析结论,可指导并修正清管器设计,控制测径清管器的运行速度,从而避免测径清管器经过U型管道的弯头时发生撞击。

When the caliper pig is passing through an elbow in the U-shaped pipeline,with unreasonable design of gauging pig and over high velocity of pig,the gauging plate will easily collide with the elbow,which causes gauging plates’ deformation.Therefore,a wrong judgment is made that some deformation on the pipeline will occure.In order to solve this technical problem,based on one determined structure of caliper pig which has been used in a U-shaped pipeline pigging application,the motion characteristics of the gauging pig has been analyzed when it is passing through the elbows.The geometric properties of elbow and caliper pig have been analyzed too,which has brought about some conclusions.At first,if the motion velocity of pig exceeds a threshold value,yield occurs at the front supporting plate of caliper pig,the gauging plate may strike with the outside arc pipe wall of elbow.And a variety of factors which determine the threshold value of pig’s velocity have been found.In addition,when the gauging plate,supporting plate,and the curvature radius of bend form a certain relationship of geometric characteristics,the gauging plate may collide with the inside arc pipe wall of elbow too.Based on these conclusions,the design plan of caliper pig can be modified and the speed controlling measures of caliper pig will be guided to avoid gauging plate crashing with elbow when caliper pig is traveling in the u-shaped pipeline.