With the advent of automated measurement of physical dimensional parameters of steel line-pipes, the industry seems to have scaled newer heights, which were previously never even imagined. The dimensional accuracy of each pipe is very critical in the overall success of a line pipe project. The quality of girth welding of pipes during laying, depends upon the close dimensional tolerances of the pipe ends. Even a slight variation in out-of-roundness or end-chamfered profile could lead to drastic irregularities in the pipe-to-pipe joining process. And the manual measuring of the pipe parameters poses a serious question with regards to their accuracy and reliability, due to the effects of man, measurement method and instruments used. There is also a huge limitation of the sampled area measured not exactly resembling the whole pipe, due to the constraints of time and the manual process involved.
This paper describes the rise of Automated Pipe Dimension Measurement System (APDMS), which measures a total of 19 dimensional parameters after real-time geometrical & trigonometrical calculations, using parametric data from 72 measurement laser scanners & sensors. The pipe coordinates are measured by laser triangulation technique principally, at each degree circumferentially and 10 mm apart lengthwise. A pipe that needs at least 45 minutes to measure all dimensional parameters manually, by 2 men and almost 25 instruments & accessories, is measured in 2.5 minutes by APDMS with mind-boggling resolution and accuracy. All this is done with a simple push of a button after one-time entering of pipe size. The fully automated system then does its job efficiently to move the pipe accordingly and scan it. The back-end software calculates the required parameters from the measured raw coordinates, evaluates them against set criteria, viz. upper and lower limits, and generates a plot that shows the variation of a parameter along the length or circumference. A calibration system in incorporated to keep the system compliant with accuracy against calibrated and certified standard samples.
Initially, we took more than 2000 trials on the whole range of pipe sizes we manufacture, after the installation of system on shop-floor. After trials and establishment, we have so far measured more than 3000 regular production pipes through this system with remarkable results.
Analysis has been carried out continuously to ensure the repeatability and reproducibility of the system is as per industry standards. This new, contactless method aims to minimize dimensional variances for fluent and effortless installation of pipes at application site, by ensuring that the dimensions are well within the defined criteria, at each and every point on the pipe during its manufacturing.