Computed Radiography (CR) & Digital Radiography (DR)
Amerapex Corporation is committed to perform high quality radiography with the state of the art Computed Radiography (CR) & Digital Radiography (DR) systems and its experienced and reliable personnel. Theses advanced technologies meet new NDT standards and codes like ASME and ASTM. The provided services include:
- Examination of welds
- Profile images for thickness and inside corrosion damage evaluation
- Tangential radiography for wall-thickness of pipes having large diameters
Advantages of CR and DR system over conventional radiography using films are:
- Decreasing time to acquire images by eliminating repeated exposures and film processing
- Decreasing amount of exposures thereby increasing productivity and safer environment
- Ability to produce consistent high quality images
- Low cost of storage, retrieval and expansion
- Ability to provide quick digital result to customers or print on paper or make CD media instead of film, saving time and costs
These unique features help our clients to save costs like plant shutdown, environment safety and longer usability of isotopes.
The advanced flexible CR plates enable our radiography team to perform radiography in hard to reach inspection areas. The DR technique using flat panels shows great capability for fast profile exposures with even higher sensitivity and larger dynamic range.
Examples of CR images:
Below shows a few examples of CR images for weld qualification and pipe projection.
Figure 1. CR image of circumferential weld in 6-inch diameter pipe taken with a 69 Ci source. The image shows 6 wires on ASTM wire type IQI.
Figure 2. CR image of circumferential weld in 8-inch diameter pipe taken with a 69 Ci source. The image shows 5 wires on ASTM wire type IQI
Figure 3. CR projection image of a 3-inch diameter pipe.
With the cooperation of IHI-Southwest Technologies, a DRT system is designed for measuring wall-thickness loss due to internal corrosion and erosion for pipes under insulation without requiring removal of the insulation. Through this technique, both internal and external corrosion defects on stretches of pipe can be detected while the pipe remains in service.
The system includes a low-level Gamma source which emits a narrow beam of radiation through a tungsten collimator. The detector is a linear array type to represent the attenuated beam of radiation after passing through the double-wall of a pipe. The source and the detector are pivotally mounted on rails which in turn are moveable on frame assemblies. The stepping motor is mounted on the frame assemblies to drive the collimator and detector along the tracking rail in scanning speed of 1 inch per second. The application range of the system is for the pipes having 4 to 24 inches (8 to 36 inches with insulation) in diameter. Special fixtures are designed to have capability of horizontal, vertical and elbow shaped pipes scanning orientations. A computer is connected to the array detector through an interface to present profiles of the pipe wall thickness.
Following figure is a typical pseudo-color display scanning image indicating wall loss in the weld and at the corrosion damage areas of 6-inch pipe under insulation.
A sample of display image of DRT system scanned on a 6-inch pipe under insulation