Materials Engineering, Evaluation, and Inspection

Evisive


State-of-the-Art Inspection and Imaging for Non-Metallic Materials



Patented in the early 1990s, the Spectrum Evisive process provides reliable, accurate and highly informative inspection results for defects located on the exteriors and interiors of non-metallic components. This advanced and field-proven microwave energy NDE technology has been used to inspect a wide range of non-metallic materials, including fibreglass reinforced piping, elastomers such as rubber expansion joints, plastics, ceramics, organic and ceramic composites and other advanced materials.

Spectrum Evisive scan equipment is portable, easy to use, intrinsically safe, does not require direct contact with the specimen and needs no couplant.



Materials That Can Be Inspected With the Spectrum Evisive Technology

The Spectrum Evisive technology can inspect anything that is electrically insulating, including:

  • Fibre Reinforced Plastic (FRP laminates, pipes, tanks, vessels, adhesive bonded and threaded joints)
  • Honeycomb Structured Composites (aircraft, space, vehicles)
  • Thermoplastics (HDPE, PP, PVC, Nylons, Butt Fusion and Electrofusion Joints)
  • Spoolable Composite Pipe
  • Reinforced and Unreinforced Rubber (expansion joints, tires)
  • Coated / Lined and / or insulated steel (pipe, tanks, vessels, structures)
  • Complex Composite or Hybrid Structures (windmill blades)
  • Ceramics
  • Polyethylene and other plastics
  • Wood
  • Kevlar
  • Spray on foam and ceramic insulation materials
  • Epoxy and polyurea linings and coatings
  • Masonry
  • Refractories


Defects That Can Be Detected With the Spectrum Evisive Technology

The Spectrum Evisive technology can detect any change in a material that alters the dielectric property of the material, including:

  • Cold Fusion in HDPE Welds
  • Misalignment
  • Corrosion on steel pipe I.D. through a liner
  • Corrosion on steel pipe O.D. through insulation
  • Delaminations
  • Disbonds
  • Cracks
  • Foreign Material Inclusions (dust in PE pipe fusion butt welds, pre-impregnated panel backing material)
  • Voids (air bubbles, poor mixing, incomplete contact, lack of glue)
  • Changes in thickness
  • Moisture or other liquid contamination
  • Mechanical damage
  • Physical changes due to chemical attack


How It Works

Spectrum Evisive scanning uses Microwave Interferometry. This technology offers material manufacturers, fabricators, installers and owner /operators the ability to peer inside materials and observe flaws that were previously undetectable.

Microwaves are radiated from the transducer to the specimen being tested.

A detectable signal is returned at each interface where the dielectric constant changes. This dielectric change can be caused by physical, chemical or material changes in the specimen, such as delaminations, cracks, holes, impurities or other defects. The reflected energy creates a signal measured in volts and that voltage is sampled at discrete locations across the specimen to create an image. The transducer may be moved relative to the specimen at any desired speed and that scanning speed need not be uniform.

It works on any non-metallic material.



System bathes the subject part in microwave energy
Reflected energy is measure with the transmitted signal to create a detector voltage
The probe (transmitter and receiver antenna) is moved over the specimen surface
The detector voltage is sampled across the specimen and an image is created


Once the data is collected, the software allows the image to be manipulated to enhance features. In addition, because the data is in digital form, the scan results can be stored and retrieved later to provide information on how a part or a defect has changed over time. This enables determination of the defect growth rate, which is critical to determining ultimate service life.


Advantages of Spectrum Evisive Over Other NDE Technologies

Spectrum Evisive scanning has a number of advantages over conventional scanning for non-metallic materials:

  • Unlike ultrasonic, microwave energy is not absorbed or dispersed in non-metallic material
  • Microwave energy is able to pass through multiple layers of materials, making detection of even deep defects simple
  • Adept at identifying delaminations (the most common flaw leading to failure of non-metallic materials) that are undetectable by radiography
  • Signal will not be lost or masked due to multiple reflectors, such as fibre reinforcers
  • This technology is particularly strong at detecting cold fusion where no ultrasonic reflections exist
  • It can also measure and image “bulk” properties, such as porosity, density, moisture ingress, and changes in chemical composition
  • No direct contact, couplant, or immersion is required to inspect a component
  • Inspection can be performed with access from a single side only


Safety

The microwave sources used in Spectrum Evisive equipment are below monitored exposure thresholds and require no special handling or precautions. Microwaves are non-ionizing, and cannot damage tissues in the way that X-rays or Gamma Rays can.


Limitations

Microwave signals cannot penetrate conductive materials, such as metal, and therefore cannot inspect material behind them. Other materials, such as water, which reflect or absorb virtually all of the microwaves that impinge on them, also make inspection of underlying structures impossible. However, this is often beneficial when inspecting dielectric materials backed by such reflective or absorptive material. For example, water-filled HDPE pipes (inspected from the OD) and plastic-coated / lined or insulated steel pipe (i.e. pipe corrosion on surfaces under the plastic layer) are easily examined by Spectrum Evisive technology.



Spectrum Evisive Scan Technology in The Field

Spectrum Evisive Scan technology has been adapted to work with many commercially available scanning devices, such as X-Y table scanners and pipe scanners. The technology has been used successfully in industrial environments such as pipelines, refineries, power plants, and chemical processing plants.





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