Eighty foot sections of pipe (especially the large 36 inch and 42 inch types that carry petrochemical products) have to be bent to follow the terrain when a pipeline is laid out. To prevent buckling of the pipe during bending operations, a device called a mandrel is inserted into the pipe and then hydraulically expanded to fit the inner diameter of the pipe. The picture below shows a bending machine with a mandrel sitting partly exposed in a cut section of 36 inch diameter pipe.

Until recently control of the mandrel and locating its whereabouts within the pipe was a totally manual operation. Indus Instruments helped CRC-EVANS of Houston, TX develop a device for untethered position detection and remote control of the mandrel. The position detection is done by sensing the phase shift of a low frequency signal transmitted through the pipe wall. A transmit coil is mounted on the bender outside the pipe and a set of orthogonal receiver coils is mounted on the mandrel inside the pipe. Remote control is achieved with a pair of 900MHz spread spectrum radio modems. A patent has been granted for the device. An updated generation of this device is being manufactured and shipped globally by CRC-EVANS.