|NDT.net June 2004 Vol. 9 No.06|
| 2nd MENDT Proceedings
External Inspection: High Resolution MFL Robotic Pipe Scanner (RPS)By: Ing. Ronald Tuls
ROSEN Inspection Technologies
There are many pipelines that cannot be inspected by using an inline inspection (ILI) method, because there are many constrains for proper inspection, such as operating conditions like low pressure, ID restrictions, no launcher and/or receiver present etc. However, the condition of these lines still needs to be investigated in order to be able to assure the pipeline's integrity, especially when the line contains hazardous products or is operated under high pressures. Replacing or modifying the line, changing the operating conditions etc. for performing a successful ILI are all possible, but, also very expensive.
There are several solutions available to obtain information about the condition of above ground pipelines, such as visual inspection, UT spot measurements, (low) resolution MFL, etc. However, by using those methods, a huge concession is done regarding the inspection results compared to the results of an ILI. By using a High Resolution MFL Robotic Pipe Scanner (RPS), this concession is minimized MFL technology has over 20 years of proven experience. ROSEN is driven by the technological challenges of designing innovative inspection tools, all consisting of state-of-the-art technology. The RPS is an inspection system that represents a completely new generation of tools, which are able to inspect a large number of pipelines that could not be properly inspected in the past.
The RPS has been designed for the 360° full coverage inspection of above ground carbon steel pipelines. The highly integrated design and optional fully wireless operation allow for excellent inspection progress. The manual or remote controlled tool is capable to clear and bypass installations such as pipe supports, making a large number of pipelines capable of being inspected. Whenever the scanning process has to end because of supports, the RPS inspection tool opens and lifts itself. In this way, the tool can bypass the support. Afterwards the RPS lowers and closes itself and continues the scanning process. Typical areas of application for the RPS system are product lines, flow lines, firewater lines around refineries and other small diameter aboveground pipelines.
The high amount of raw data recorded by the tool is checked in independent steps for completeness and quality. The data is then transformed into a format that provides easy access to all areas of interest and enhances the performance of the analysis software. Automated data evaluation searches all data recorded and detects, identifies and classifies all significant features. Results of this automated process are stored in database files.
The RPS survey results can be reported in two formats: a hard copy report with comments, lists, statistics and graphics and in a client software package, which includes both raw data and the database system. This is a basic requirement for pipeline management systems in terms of quality control and lifetime prediction. It provides digital information about all the data recorded during the survey with full and fast access to the database and to the raw inspection data. Comprehensive information about each defect can be viewed, evaluated in detail, and easily printed for field use.
Case analyses have shown that excellent RPS inspection results have led to a cost saving factor. By using the RPS, clients have been able to decide which parts of the pipeline are in good condition and which are to be replaced. Also, decisions could be made on which parts remedial action was most urgent. This facilitates proper planning in order to minimize the effect of operational constrains. Since most features had been caused by internal corrosion, visual and/or UT spot measurement inspections would not have been sufficient.
By taking into account the inspection possibilities of the high resolution MFL Robotic Pipe Scanner, the integrity of many above ground pipelines can now be economically and soundly assessed. The RPS is part of a completely new generation of inspection tools, using state-of-the-art-technology, which enables clients to make proper and timely decisions for safe operations of above ground pipelines.