Defect inspection magnetometer, used in e.g. high pressure gas pipelines, comprises magnetic sensor rings, multiplexer, amplifier and signal processing instrumentation

摘要

Magnetic sensor signals are connected to multiplexer inputs. Its outputs are connected to amplifier inputs. The amplifier output is sent to instruments measuring, processing and recording the data Preferred Features: Semiconductor sensors are employed. The tubing is magnetized through internal contact with two belts of ferromagnetic brushes installed on magnets. The magnetic field sensors are installed between the brushes, forming a further ring adjacent to the internal surface. After the brush belts, a second sensor belt is mounted, downstream of the instrument body. A temperature sensor follows the first and/or second belt of sensors. A continuous current source is connected to the sensor inputs. The instrument measures the voltage at the sensor outputs. The magnetic field transducer assembly, includes a current stabilizer and the sensors are connected in series to this supply circuit. Cavities in the transducer assembly are filled with a composite, and the sensors each have a magnetically-sensitive region surrounded by a non-sensitive region. Minimum thickness of the layer between a sensor and the medium carried, is at least 1 mm. On the magnetometer body a distance meter is mounted. One of its outputs is connected to a generator of sensor addresses for interrogation. Command inputs of the multiplexer are digital and are connected to outputs of the address generator.