Put That in Your Pipe and Check It

Explosions caused by leaking gas pipes under city streets have repeatedly made headlines in recent years. Now a small robotic device devised by MIT doctoral student Dimitrios Chatzigeorgiou, SM ’10, and collaborators can quickly and accurately pinpoint leaks in gas or water pipes or oil pipelines by sensing even tiny changes in pressure. The system “can detect leaks of just one to two millimeters in size, and at relatively low pressure,” he says.

The current systems for testing pipes, which detect sound or vibrations from the leak, are very time consuming and require expert operators, he says, whereas the new device can move through the pipes as fast as three miles per hour and is almost entirely automated.

The device consists of a small robot, with wheels to propel it through the pipes, and a solid disk attached to a cylindrical membrane that forms a seal across the whole width of the pipe. When a leak is encountered, liquid flowing toward the leak distorts the membrane, pulling it slightly toward the leak site. Sensors similar to those used in computer track pads detect that distortion and send the information wirelessly to an operator’s computer.

The membrane is so sensitive that Chatzigeorgiou and his colleagues believe the system can detect leaks a 10th to a 20th the size of those that can be found by most existing methods. At present, it can only inspect pipes of fairly uniform size, but the researchers are working on a version that will have more flexibility to deal with variations in size caused by damage, obstacles, or scale buildup inside the pipes.