Typically, when an underground natural gas pipeline leaks, the affected section must be excavated and replaced. Soon, however, modular robots for pipe inspection and repair may make this practice unnecessary. Scientists at Carnegie Mellon University are developing the device, led by Professor Howie Choset and research scientist Lu Li. It is designed to travel through pipelines, using umbilical cables to transmit live video to (and receive) instructions from workers on the surface.
The heart of the robot is its mobile module, which has a 2-inch wheel on the bottom and top. These three electric wheels adhere to the inner wall of the pipe and provide traction to pull other components forward.
These "other parts" can weigh up to 60 pounds (27 kilograms) and include a battery module, a mapping module (which uses high-definition optical sensors and lasers to measure and 3D image the inner surface of the pipe), and a repair module.
The latter module consists of a rotating nozzle that delivers a continuous spray of fast-hardening air-tight resin into the wall where needed to seal any cracks or other defects. With the help of an artificial intelligence image analysis system, staff discovered these issues through the output of the drawing module.
Other repair modules can be used to perform tasks such as welding leaks between pipe sections.
Currently, the robot can inspect about 9 miles (14.5 kilometers) of 12-inch (305 mm) diameter pipe in eight hours, or coat about 1.8 miles (3 kilometers) of pipe with resin in the same amount of time. Its umbilical range is 200 feet (61 meters), though scientists hope to eventually increase that number to 2 kilometers (1.2 miles). Additionally, they are developing a small robot for 6-inch (152 mm) pipes.
The U.S. Department of Energy, which funds the project, estimates that using robots to repair pipes from the inside could end up being 10 to 20 times cheaper than digging up and replacing them.
The video below shows two views of a robot applying Vaseline (instead of resin) to the inside of a clear pipe.