Deployment of Inductance-Based Pulsating Sensor Toward Development of Measurement Technique for Ovality in Pipe

This paper presents a handheld robust battery-operated contact-based ovality meter suitable for the measurement of ovality in pipeline in a plant site or in any industrial establishment. The ovality meter is mainly composed of a specially designed inductor with ferrite core. This inductor constitutes the part of an LC-type logic gate oscillator (LGO). A change in the sensor position during the measurement of pipe diameter causes a small change in inductance, which in turn changes the pulse frequency of the LGO when it is powered by 5 V dc. Thus, frequency, the output of the instrument that is displayed on the liquid crystal display of the embedded processor, is a function of displacement. By measuring the diameter of pipe specimen at different locations, the ovality is computed. In the present design, the range of position measurement is about 25 mm. The sensitivity in position measurement up to 10 mm is ~850 Hz/mm, which further reduces in higher range (>10 to 25 mm). Such a sensitivity in the position measurement seems to be quite suitable for ovality measurement.