Since the year 2000, Mechanical Integrity has developed a series of special tools which operate with a variety of imaging technologies. Some of the scanning devices are able to collect ultrasonic data while scanning on surfaces at 70⁰F. These various scanning systems "crawl" on piping and produce images generated by ultrasonic, EMAT, microwave and digital X-ray technologies. These projects funded by the American Petroleum Institute, Eli Lilly and the Edison Welding Institute have all resulted in equipment which is being used reliably in the field by personnel either supplied by or trained by Mechanical Integrity Incorporated.

The device designed and developed for Eli Lilly uses a mast-based system to inspect three welds, the shell and the lower head of a cryogenic vessel. The rollout shown in Figure 1 shows in a "C" Scan format the thinner areas depicted in green and yellow. The thinnest areas are associated with the weld heat affected zone.

Following the high pressure steam line failures at a number of sites, including Mohave, Combustion Engineering commissioned a project, working with EPRI (Electrical Power Research Institute). The purpose of the project was to develop a crawler system, which could deploy video, eddy current, ultrasonic and a debris removal capability. The system when deployed had to be capable of passing through two “S” bends in a Steam Line, while continuing to perform the inspection. Mr. McMillan was the principal designer and developer of this system.

Mr. McMillan headed up the development of equipment to inspect the solid fuel motor sections after the Challenger and Trident failures. The project included the development of the inspection technique to identify the areas of dis-bonding between the casing and the adhesive to the solid fuel. The project included the design and supply of the mechanical hardware, motor controls; twelve systems were deployed to various inspection locations shown in Figure 3. The total project included training and the supply of inspection personnel to United Technologies and Martin Marietta.

As a portion of a Joint Industry Project with API (American Petroleum Institute) an ultrasonic scanner and deployment system has been developed which operates on surfaces at elevated temperatures. The scanner has now been used extensively in the US and in the Middle East, by Saudi ARAMCO.

Scanners developed for the inspection of piping and tank floors, to examine for corrosion and pitting. The scanners can be adapted to use both permanent and electromagnetic transducers. The equipment has been designed to operate on piping from 4.0" in diameter to flat plate and has also been used on the inside of spheres.

The project involved the development of a Phased Array Inspection System capable of examining the bridge pin from the end and from the hole which is centered throughout the length of the pin. Two scanning systems were developed in conjunction with a development program with EWI (Edison Welding Institute) The project was completed in the fall of 2005.

The novel inspection technique is based on monochromatic, phase coherent electromagnetic radiation in the 5-50 gigahertz frequency range (i.e. - microwaves). The sample to be examined is exposed to microwave radiation at discrete locations along a path whose coordinate locations are known and are returned as part of the data field, thus creating a map of the specimen. A detectable microwave signal is also returned everywhere along the path and a differing signal is generated at each interface where the dielectric constant changes (e.g. - where there are delamination, cracks, holes, impurities, or other defects).

The return signal is generated based on the angle of incidence, the differential in the dielectric constants between the materials (which is related to the index of refraction), the surface geometry, and other factors. Early testing proved that this technique can successfully detect cracks, voids, foreign material inclusions (e.g., water or oil), thickness changes, density changes, delaminations, changes in dielectric constant (which in rubber may, for example, indicate hardening), and other defects in, essentially, any dielectric or bulk dielectric materials. It was also found that different types of defects have distinguishable and reproducible characteristics. The testing also showed that the transducer may be moved relative to the specimen at any desired speed and the scanning speed need not be uniform.