Measuring device comprises coil arranged on drill column for producing alternating field, sensor arranged on drill column for sensing alternating field, and computer to analyze signals from sensor

摘要

The measuring device comprises a coil (4) arranged on a drill column for producing an alternating field; a sensor arrangement (10, 12) arranged on the drill column for sensing the alternating field; and a computer (24) connected to the sensor to analyze the signals from the sensor. An Independent claim is also included for a process for carrying out the determination of the drill column throughput. Preferred Features: The coil and/or the sensor are placed as coils arranged coaxially to the drill column elements. The sensor has two coils arranged axially to each other.