The Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) has endorsed a commercial solution to inline inspections of unpiggable natural gas pipelines. Developed by Pipetel, the Explorer 20/26 robot is a second-generation prototype that can maneuver its way past obstructions that would block the progress of most pigs.
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Download NowPHMSA’s 2002 natural gas integrity manage¬ment rule created a technol¬ogy gap for pipeline operators trying to inspect unpiggable pipelines in high consequence areas. These unpig¬gable systems cannot be inspected using traditional inline inspection technologies because they lack launching/receiving points or contain certain valve types, diameter changes, or other cir¬cumstances that will not allow internal inspection equipment to pass through.
Tetherless design
At 14 feet long and 800 pounds, the Explorer 20/26 is equipped with cameras on each end and a high-resolution sensor for inspection. The tetherless design allows the robot to be controlled wirelessly and articulate and transform its orientation. The robot enters the pipeline through a launch tube attached to an installed flange fitting. A 2-inch opening, or hot tap, is installed near the flange and every two-thirds of a mile to allow robot operators to communicate with the device via a small antenna and inspect the pipeline for several miles. Induction probes are also inserted through the hot taps to recharge the batteries of the Explorer to facilitate extended inspection distances.
Technicians operate the robot, conduct the inspection, and collect inspection information on a graphic user interface (GUI). Displayed information on the GUI includes live video from both cameras, the current orientation of the robot, and other operational aspects and parameters.
Defect characterization
The Explorer 20/26 is an upgrade from its first-generation cousin, the Explorer I. While the previous Explorer could traverse around most obstacles that caused certain pipeline systems to be viewed as unpiggable, the newer version not only visually inspects these systems, but detects and characterizes defects.
The Explorer 20/26 was recently demonstrated for the first time in a Burbank, California, natural gas pipeline.
The 2002 Pipeline Safety Improvement Act directed the DOT to collaborate with the Department of Energy and the National Institute of Standards and Technology to carry out a program of research, development, demonstration, and standardization to ensure the integrity of pipeline facilities. Since the program’s establishment, the PHMSA has provided over $67 million for 183 projects addressing better diagnostic tools, testing of pipelines, stronger materials, improvements in locating and mapping pipelines, prevention of outside force damage, and effective leak detection.
A PHMSA fact sheet on the Explorer 20/26 is at https://primis.phmsa.dot.gov/matrix/FilGet.rdm?fil=7546.