METHOD AND APPARATUS FOR MEASURING WALL THICKNESS, OVALITY OF TUBULAR MATERIALS
First Claim
1. A method for measuring the maximum and minimum diameter and ovality of a tubular comprising:
- calculating the circumference of the tubular;
calculating the mean radius of a circle having the measured circumference;
contacting the surface of the tubular at two points in a plane substantially perpendicular to the major axis of the tubular;
measuring the distance from the surface of the tubular at a point half way between the two points of contact to the ultrasound transducer at a known distance from a line connecting the two points of contact;
using the mean radius to calculate the theoretical pipe center and circumference;
calculating the arc height of the tubular by adding or subtracting the water path measurement to a fixed distance defined by the fixture;
calculating the maximum and minimum diameters of the pipe relative to the theoretical mean radius and center;
calculate the ovality of the tubular by calculating the difference between the maximum and minimum diameters per revolution; and
correlating ovality and wall thickness simultaneously using essentially the same apparatus and ultrasonic probe.
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Accused Products
Abstract
The wall thickness and ovality of a tubular are simultaneously determined. The theoretical radius of a pipe is computed from a measurement of its circumference. An ultrasonic device conventionally used to measure the wall thickness of tubulars is adapted to also measure the maximum and minimum diameters and ovality by equipping or utilizing existing ultrasound inspection device with contact surfaces which contact the tubular at a fixed distance apart and at a known distance from the surface of the ultrasonic transducer. The contact surfaces define a chord of known length on the tubular under test. The mean radius of the tubular may be computed from multiple water path measurements around the circumference relative to a known fixture. The maximum and minimum diameter and ovality are calculated from the measured differences in distance from the surface of the tubular to the ultrasonic transducer and the theoretical circle. Wall thickness and ovality may be correlated relative to position by using the same apparatus for both measurements.
37 Citations
1 Claim
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1. A method for measuring the maximum and minimum diameter and ovality of a tubular comprising:
- calculating the circumference of the tubular;
calculating the mean radius of a circle having the measured circumference;
contacting the surface of the tubular at two points in a plane substantially perpendicular to the major axis of the tubular;
measuring the distance from the surface of the tubular at a point half way between the two points of contact to the ultrasound transducer at a known distance from a line connecting the two points of contact;
using the mean radius to calculate the theoretical pipe center and circumference;
calculating the arc height of the tubular by adding or subtracting the water path measurement to a fixed distance defined by the fixture;
calculating the maximum and minimum diameters of the pipe relative to the theoretical mean radius and center;
calculate the ovality of the tubular by calculating the difference between the maximum and minimum diameters per revolution; and
correlating ovality and wall thickness simultaneously using essentially the same apparatus and ultrasonic probe.
- calculating the circumference of the tubular;
Specification