Digital radiography (DR) – A modern method of recording a radiograph in digital form. Among digital radiography systems, there are indirect and direct systems. Intermediate systems for image recording use a phosphor-coated memory plate, which saves the latent image, which is read later by a special scanner. Direct systems use a digital CCD or CMOS detector to record radiation. The image of the tested object is displayed on the computer screen immediately after the exposure. Data collected this way can easily be digitized.
Navitest has a system for direct digital radiography enabling scanning of objects with a thickness up to 85 mm. While the sensor and the source are working in the radiation zone, the operator receives an image on the tablet screen, staying outside this zone. Detection of discontinuities (e.g. porosity, corrosion, erosion or cracks) already during the test enables intermediate decision to continue works with the object.
Digital radiography is most commonly used to monitor tube conditions and tanks as it provides detection and assessment of corrosion (including pitting corrosion). The thickness of the pipe or tank and the type of insulation material or coating is irrelevant to the effectiveness of the test. Corrosion mapping using digital radiography is an ideal way to monitor material damage – periodic testing allows measurements to be compared. Corrosion mapping is an effective way of seeing different material damage.
Digital radiography can also be used to wall thickness measurements; images of examined objects can be made by the insulation. There is no need to switch off or limit the functionality of a diagnosed device or remove insulation even in places such as refineries, drilling rigs, power plants, etc.
Digital radiography, just like the traditional, also allows you to evaluate the quality of welded joints, solders, etc., both during manufacturing and in operation.
The following characteristics have contributed to the increasing popularity of digital radiography in diagnostics in various industries and fields of industry:
- wide dynamic range of image plates and high exposure tolerance, and consequently a significantly reduced need to repeat images,
- precision of measurement,
- shorter exposure time than traditional radiography and the resulting lower radiation dose (which benefits the environment and the operator),
- fast and easy access to high quality images - the result of the study is obtained immediately after the exposition without photochemical processing, and professional software enables improving of the image quality to achieve the desired image characteristics.
- the obtained image can be easily copied and transferred. Standard computer software (.tiff format files) is sufficient to view a digital image of the exposed object. Until now, making radiographs available for viewing outside the NDT laboratory required their physical transported. Digital image recording enables presenting the results to a client anywhere in the world.
- Data archiving
Application
Our system enables testing of pipelines, pressure vessels, welded joints, valves, reinforcements, rotor blades, engine components, turbine blades, other types of castings and forgings, plastic wires and many other. DR is also used to check the completeness or correct placement of individual elements in larger components.
Important to know
The result of the examination is obtained immediate after the exposition without photochemical processing, and professional software enables improving of the image quality to achieve the desired image characteristics and significantly reduces the need of repeating expositions.
The digital image of the exposed object can be copied and emailed. Standard PC software for .tiff files is enough to show the results to a client anywhere in the world.