When performing internal pipe inspections and internal tunnel inspections, measuring ovality and small defects such as cracks, pitting, and spalling can be accomplished with the ULS-100. The ULS-100 digitally captures clouds of 3D points which can be surfaced to represent the object being scanned. This is achieved by capturing a series of adjacent data points, building a complete digital 3D model. This case study demonstrates the performance of the ULS-100 for high precision measurements in a section of tunnel. A tunnel section was created using a rolled piece of sheet metal with a variety of known targets to scan.
Measuring the ovality of a pipe or tunnel and understanding how this measurement changes over time is an important component in determining the structural integrity of the asset. Using the ULS-100 the tunnel profile can be measured accurately. Since the ULS-100 captures a complete swath of points at a given location the position and orientation of the scanner head relative to the tunnel itself is irrelevant, ensuring that the an accurate measurement is taken every time. This is in comparison to many existing solutions for tunnel profiling where measurements are captured on a single plane. If this plane is not perpendicular to the direction of the pipe or tunnel, the results will be interpreted incorrectly. For example if a tunnel section is perfectly circular and a single profile scanner is used at an angle to the tunnel section, an oval profile will be captured. Similarly in a tunnel section that is oval in shape, using a single profile scanner it is possible to incorrectly capture a circular profile.
With the ULS-100, a swath of geometry data is captured allowing the person viewing the data to understand the direction of the tunnel and thus the true profile.
Using the rolled sheet pipe section a single profile was captured allowing accurate tunnel and pipe ovality measurements to be obtained. Because a complete swath of data was captured by the ULS-100 Underwater Laser Scanner, the profile of the tunnel perfectly normal to the direction of the tunnel is obtained.
Small features on the tunnel wall can often be important for proper assessment. Using traditional Underwater Sonar and Underwater Video inspection techniques these features can not be adequately quantified. For more detail, Click here to read a technical paper comparing sonar and laser measurement techniques. Two small nuts were glued to the inner side of the tunnel wall and scanned. With the captured points surfaced, not only were the nuts easily identified but the size of the nuts could be measured.
At the location where the edges of the rolled sheet overlapped, a flap of the sheet was cut and lifted slightly. Not only was this accurately modelled by the ULS-100 but the 1.2mm edge of the sheet metal was also accurately modelled. Additionally, a small slit was cut into the side of the pipe section. This small underwater defect was accurately measured using the ULS-100 underwater Laser Scanner.
By using the ULS-100 to obtain quantitative information about these fine details in underwater infrastructure, it is possible for engineers and asset owners to obtain a more complete understanding of the asset preventing the need for significant assumptions while ensuring safe continued operation.
The ULS-100 is easily integrated into a wide range of underwater robotic equipment. 2G Robotics Inc and Inuktun Services Ltd. have partnered to provide a turnkey pipe and tunnel inspection solution. In addition to the high precision measurement capability of the ULS-100, Inuktun selected this sensor for integration with the Versatrax 150TM because of the ease of use and non-proprietary nature of the captured data. Unlike other profiling technologies, the 2G Robotics system includes all the software you need to complete pipe profiling on your own, without having to send files back to the factory. Multiple scans can be merged into a single 3D point cloud and exported as a .csv file for import by any number of standard CAD packages for further work.
Please contact 2G Robotics for more information about the ULS-100 and how it can be incorporated into your inspection system.