MAGNETIC FLUX PIPE INSPECTION APPARATUS FOR ANALYZING ANOMALIES IN A PIPELINE WALL

摘要

An apparatus for analyzing anomalies such as cracks, corrosion and the like in a pipeline wall is provided. The apparatus is formed of one or more cylindrical body sections. A series of magnetizing units are mounted around the circumference of the body. Each magnetizing unit is formed by a backing bar, brushes which are capable of inducing a magnetic field, sensors which are capable of measuring magnetic flux leakage caused by anomalies in the wall and bearing wheels which reduce wear on the brushes and sensors. The backing bar is flexibly mounted on the body so that it can follow the contour of the pipeline wall as the apparatus moves through the pipeline. The backing bar has steel-containing brushes mounted on either end atop magnets of opposite polarities such that a magnetic field may be transmitted to the pipeline wall. The brushes are ideally formed by steel cables encased in polyurethane and mounted on a steel shell. The sensors are mounted in the central part of the backing bar, between the brushes. The sensorspreferably have a parallelogram cross-sectional shape and are molded of polyurethane or other suitable material so that they are flexible enough to follow the contour of the pipeline wall as the apparatus travels through the pipeline and, hence, maintain the orientation of the sensing element in the sensor body in relation to the pipeline wall. A wear plate and wear pads may be mounted on top of the sensor body for reducing wear on the sensor.