By Dagmar Hippe-Wallenwein
In November l895 Prof.Dr.W.C. Röntgen astounded the scientific world with his discovery of X-rays.
A few weeks later C. H. F. Müller with his years of experience in glass blowing was able to construct in his Hamburg factory the very first commercial X-ray tube for one of the local hospitals. Using this tube the first X-ray of a human hand was made in January 1896 thereby laying the foundation stone of what was to become a major technical industry.
In 1899 C. H. F. Müller was granted patent rights for his X-ray tube with water-cooled anticathode.
Two years later Müller was awarded the gold medal by the Röntgen Society of London for his improved watercooled X-ray tube with secondary electron capture. This tube has been preserved and can still be seen in the Science Museum in London.
In their time these ion tubes for diagnostic purposes represented the acme of technological achievement, and as the C. H. F. Müller industry expanded his reputation in the scientific world grew rapidly.
The association between Müller and Philips was fully realised with a merger in 1928 giving Müller the ideal opportunity to utilise the experience of his new partner in further developing his ideas and research. This merger with an internationally active company opened up a fully new era in the field of X-ray technology. The rapid developments in X-ray technology in the 1930's led to an increased demand for Röntgenmüller equipment, necessitating the extensive manufacture of X-ray systems for a variety of practical applications in the medical, physical research and industrial fields. Using the firm foundations built up by Röntgen and Müller, Philips have established themselves as the "leaders" in modern X-ray technology.
Oil and gas pipelines and boilers and similar containers can be subjected to severe stress, strain and other effects. X-ray inspection makes sure that vital quality and safety standards are adhered to at all stages in their production and use. Stationary, high-performance constant-potential X-ray systems represent the ideal inspection method for such items, whilst mobile constant-potential systems come into use in general assembly and maintenance operations. During actual production radioscopic inspection, utilising X-ray image intensifiers and TV-facilities, plus X-ray radiography, can be usefully employed. The illustrations show some of typical applications.
Fig. 6: Large oil and gas pipes being inspected with Philips' 160 kV constant-potential X-ray system and 9 inch (23 cm) image intensifier/TV-system.
Inspecting the welded seams of a pressure tank using the 320 kV constant potential X-ray system.
Inspection of a preassure vessel with the 420 kV X-ray tube MCN 421
Maximum safety is an essential pre-requisite in nuclear engineering, and X-ray inspection has become a widely-used technique in ensuring that this safety is assured throughout. Indeed, for a large number of nuclear components the technique is obligatory.
Nuclear power stations, for example, are noted for massive, heavy and thickwalled structures whose X-ray inspection demands inspection systems that must be taken to the structure rather than the other way around. Reactor chambers and fuel ement vessels are typical cases in point. That is why the Philips X-ray systems are so in demand in this industry. With the wide constant-potential range and sturdy metal-ceramic X-ray tubes, these systems are the first choice where safety and quality are vital parameters.
Fig. 9: Pipeline-weld inspection at a nuclear power station using the mobile 160 kV constant-potential system.
|In Shipbuilding and Off-Shore Installation|
Safety at sea requires a high standard of quality. When building new ship or off-shore installations, or for general repairs and maintenance, X-ray inspection of welded seams substantially contributes towards achieving the necessary levels of quality and safety.
Fig. 10: X-ray inspection of heavy castings using the stationary constant-potential 420 kV X-ray system in conjunction with a 6 inch (15 cm) image intensifier ITV-system.
Fig. 11: This 420 kVX-ray system has been fitted to a stacker truck for mobile use in shipbuilding and general construction industries.
In many areas of research it is also necessary to know what is going on
inside the sample. Without X-rays this would be virtually impossible unless the item was "broken-open". As there are usually many stages of "inside" observations required in research such action is obviously unacceptable.
What happens, also, when there is an excess release of energy within a nuclear fuel rod container?
Another area is dosimetry where X-ray systems are used as reference sources for calibrating dosemeters.
Fig. 12a: Philips industrial X-rays are ideal for
observing fast transient occurences - here
the complete system for an observation
length of approximately 600 mm. The set
up uses three MG 420 X-ray systems, three
9 " image intensifiers and six high-speed
cameras and associated control units.
Fig. 12b: Test set-up, using three 420 kV metal- ceramic constant potential X-ray tubes, MCN 421, for observing the quickly elapsing process of an excess release of energy in a model of nuclear fuel rods.
X-ray inspection is now a self-evident means of quality assurance in the fields of aviation and aerospace, both in production and general repair and maintenance. The great advances in aviation and aerospace would have been inconceivable if it had not been possible to conduct intensive non-destructive testing. The pace of developments in this field is unparalleled. As with nuclear engineering, maximum safety is the essential need. In these important and exciting industries the full and proper inspection of welds, of castings and materials like glass or
carbon fibre reinforced plastics, have become routine practices. An enormous volume of various components now undergoes full X-ray inspection - even during normal maintenance procedures.
With the ComScan system Philips offers a worldwide unique inspection method especially for use in the aircraft industry. ComScan was designed for inspection of light-absorbing materials, e.g. carbon-fibre reinforced plastics, and only requires access to one side of the specimen.
Fig. 14: In motion radioscopy of /arge-area aircraft components. X-ray tube and image intensifier/TV-system are moved by a double DANA III overhead suspension system.
Fig. 15: Inspecting important engine-mounting components for a Boeing 727 using the mobile 160 kV constant-potential X-ray system.
Quality production requires effective quality assurance, which in turn relies heavily on non-destructive testing. X-ray inspection is increasingly applied in electrical engineering industry and in electronics to ensure safer quality of heating rods, batteries, microswitches, encapsulated components, integrated circuits, thermoelements, etc.
Advanced image processing techniques offer new capabilities for industrial X-ray inspection in this branch.
Fig. 16a: X-ray system designed for fully automatic inspection of undrilled multilayer pcbs. The relative offset between the individual layers is measured before subsequent machining takes place.
Fig. 16b: Multilayer pcb during X-ray inspection. At this production stage the pcb is not yet etched and drilled.
Fig. 16a, 16b
Although non-destructive testing techniques - including X-rays and ultrasonics - have been available to industry for a number of years, they have not yet been widely used in the metal-casting industry. This has been particularly true in the small and medium sized foundries and departments responsible for the inspection of incoming components.
In recent years, the growing demand for quality - especially in the automotive industry - has meant that the allocation of orders has become increasingly dependent upon X-ray inspection. Competitive companies are turning to this type of inspection to ensure their quality standards.
To make this step easier and based on length experience and know-how, Philips has developed standard radioscopic inspection systems-the MU 15F, MU 17F and MU21F.
These systems cover a wide range of application, especially in the light metals industry, for the radioscopic inspection of a variety of components, either individually or in large and small batches.
Fig. 17: The MU60F X-ray radioscopic system is extremely flexible. The main C-shaped manipulator carries the 160 kV constant-potential X-ray tube and the imaging system. Various manipulators can be used for moving the test specimens; the 100 daN turntable-type manipulator is shown in the illustration below. A roller conveyor facility permits the system to be integrated in a production line.
For economical inspection of large quantities, Philips has developed special radioscopic inspection systems. Their application ranges from the inspection of light alloy castings to the inspection of steel. 6" or 9" X-ray image intensifiers with TV-chains are being used as imaging systems.
The selection of manipulators ranges from the manually operated version to the automatically operated 6-axes-robot.
Fig. 18a: X-ray radioscopic system MU46F for inspecting thick walled parts. Equipped with a 320 kV constant-potential X-ray system MG 321. it is used for inspecting steering knuckles of nodular graphit cast-iron.
Fig. 18b: X-ray radioscopic system MU40F was developed for inspecting larger parts up to 30 kg. Loading and unloading can be accomplished externally from the cabinet for easy handling.
Fig. 19a: X-ray radioscopic system MU57F. Equipped with a 6-axes robot and a 160/ 320 kV constant-potential X-ray system MG 161/321, this system is used for inspection of incoming goods. Simultaneous inspection and loading or unloading results in a high degree of efficiency.
Fig. 19b: X-ray inspection system (160/320 kV) for inspecting parts supplied. Specimens up to 2300 mm length can be tested. For inspecting cylindrical parts a turntable manipulator is available.
ComScan is the name of the new method of non-destructive testing from Philips that allows the depth of a defect to be determined radioscopically for the very first time. Separate slices of the specimen are inspected to prevent
geometric super-imposition complicating evaluation of the image.
Compton backscattering, regarded as unwanted effect when using transmission
radioscopy, is used to advantage with this generation technique.
ComScan is therefore suitable for recognising defects near the surface of large-volume components such as aerofoils or the sealing surfaces of housings. Moreover, materials with low coefficients of absorption can now be inspected with high-energy X-ray spectra for improved efficiency.
In this carbon composite sandwich. ComScan clearly detects lack of material. Even density differences in the material are visible.
ComScan examines an aluminium honeycomb behind an aluminium plate. revealing honeycombs filled with water.
The delaminations and cracks revealed by ComScan in stabilizers/ringers in an all-carbon reinforced wing had escaped detection by traditional X-ray methods.
|The X-ray tube and detector are accommodated in a common detector head. The big advantage of this is that ComScan only requires access to one side of the specimen.||