Typically, when a leak occurs in an underground natural gas pipeline, that section of pipe must be excavated and replaced. But modular robots that inspect and repair pipes may soon make this task unnecessary.
The device is currently being developed by scientists at Carnegie Mellon University, led by Professor Howie Choset and research scientist Lu Li. It is designed to travel through pipelines utilizing umbilical cables to relay live video and receive commands to crews on the ground.
At the heart of the robot is a mobility module equipped with two 2-inch wheels on the bottom and one on the top. These three motorized wheels press against the inner wall of the pipeline, providing the traction needed to pull everything else along.
“Everything else” includes the battery module, potentially weighing up to 27 kg (60 lb). A mapping module that uses HD optical sensors and lasers to measure and 3D image pipeline internal surfaces; And a repair module.
In its current setup, the latter module consists of a rotating nozzle that applies a continuous bead of fast-curing sealing resin to the wall as needed to seal cracks or other defects. The crew discovers these issues through the output of the mapping module with the help of an AI image analysis system.
Other repair modules could potentially be used to perform tasks such as welding leaking joints between pipe sections.
The robot can currently inspect about 14.5 km (9 miles) of 12-inch (305 mm) diameter pipe in eight hours, or perform a resin coating of about 3 km (1.8 miles) in the same time. The echelon range is 200 feet (61 m), although scientists ultimately hope to increase that figure to 2 km (1.2 miles). They are also developing a smaller version of the robot for 6-inch (152 mm) pipe.
The U.S. Department of Energy, which is funding the project, estimates that using robots to repair pipelines from the inside could ultimately be 10 to 20 times cheaper than excavating and replacing them.
The following video shows two views of the robot applying Vaseline (in place of resin) to the inside of the clear part of the pipe.
Petroleum jelly distribution using robots
Source: Carnegie Mellon University