Using the Low Frequency Electromagnetic Technique (LFET), the lightweight, aluminum, TesTex Line CAT quickly and accurately scans the outer diameter (OD) of ferrous and nonferrous pipes and detects gradual wall loss, pitting, gouging, and other defects.
The Line CAT comes in many variations, and with its modular design, featuring many interchangeable parts and components, the versatile Line CAT can be quickly adapted to fit many pipes starting from 3 inches (For those pipes less than ten (10) inches in diameter, the Line CAT performs 360° scanning. For larger pipes, it scans 120°, or one-third of the circumference, with each pass. Its can also be outfitted with an optional encoder.)
The TesTex Line CAT can be propelled by an optional remote-controlled, magnetic wheeled “crawler,” which is capable of traveling up to ten (10) feet per minute. (See below.)
The crawler’s contoured top shell supports and stabilizes the main sensor array. The sensor array itself, is made up many scanning pods that contour to the actual geometry of the pipe via a flexible coupling system. The Line CAT travel around bends and over welds, and all components can operate in Arctic conditions down to -40° Fahrenheit. It scans through uniform scale, rust, or coatings. Scan results are shown on a high-resolution 3D graphics display. In addition, the Line CAT can be shipped overnight anywhere in North America and within 3-10 days anywhere in the world.
The Line CAT system was field tested on sections of two insulated crude transit pipelines on the North Slope of Alaska. The insulation was removed from both pipelines. One pipeline had anti-corrosion tape, while the other was bare. These sections were tested with three different techniques: (1) the Electromagnetic Acoustic Transducer Technique (EMAT), (2) Automated Ultrasonic Thickness (A.U.T.), and (3) our Low Frequency Electromagnetic Technique via a Line CAT system.
Although A.U.T was able to give actual thickness readings, it had a very slow scan rate. EMAT displayed scan rates faster than the A.U.T., but the Line CAT was by far the most productive. Both EMAT and LFET demonstrated a 100% POD (probability of detection) for 25% wall loss isolated pitting at a 3:1 aspect ratio. EMAT displayed a reduction in the scan rate over the tape-covered section, from 1,000 ft per day on uncoated piping to 500 ft per day on tape-coated piping.
The scan rate of LFET remained unchanged over the tape-coated piping (approximately 10 ft per minute). Also, LFET has a false positive over call rate of less than one percent (1%). The field test clearly showed that the Line CAT’s LFET Technique was the most efficient method with the tape coating and had the highest overall productivity for the job.