APPARATUS AND METHOD FOR DETERMINING THE POSITION OF THE ENDOF A THREADED CONNECTION, AND FOR POSITIONING A POWER TONG RELATIVE THERETO

摘要

Apparatus and method for positioning a power makeup/breakout device, commonl y referred to as a ~power tong unit~ along the longitudinal axis of a tubular, with respect to the end of a connection. A probe having an electric coil is mounted on the power tong. An alternating electric current is flowed through the coil, creating an electro-magnetic field emanating from the coil. Positioning the coil such that the tubular connection is within the magnetic field, then moving the coil such that the connection end moves within the magnetic field, permits the connection end to be seen as a discontinuity, by the principles of eddy current testing. The location of the connection end i s used to manually position the tong, or is input to a processor and then to a power positioner, which properly positions the power tong with respect to th e connection end.