Non-destructive Testing of Wire Ropes
Non-destructive Wire Rope Testing by Means
of Magneto-inductive Measurement
The safety inspection of wire ropes on regular basis is essential. Whether track ropes and traction ropes of lifts and cableways, bridge catenary cables or haulage cables, e.g. in mining: Inspection and testing for possible damage or fractures and the reliable load bearing capability is crucial for the safe operation and use of all kinds of plant, machinery, and buildings. This also applies to high-duty wire ropes used as anchoring ropes for cranes or masts as well as on hangars, and for wire-rope reinforced conveyor belts.
In order to monitor and inspect all these wire ropes effectively and reliably, our technology is being employed for non-destructive wire rope testing. For more than 50 years now, Dr. Brandt GmbH has been developing and producing magneto-inductive rope testing devices, which are used for the gentle and reliable testing of ropes. This enables plant operators and machine owners to carry out a check of the structural integrity of the ropes in addition to visual monitoring and inspection. In other words, certain signs of wear and tear and weak points such as cracks or fractures deep in the rope, which camera technology or visual inspection are unable to detect because they exclusively allow a coverage of the external or outer surfaces, are reliably detected by magneto-inductive testing of the entire rope body and can subsequently be assessed for their effects and consequences.
Basic Functioning of the Magneto-inductive
Wire Rope Testing
Various testing devices are put to use for the magneto-inductive testing of wire ropes. They are either stationary, in which case the rope moves through the testing arrangement (e.g. in the case of a chairlift), or mobile, i.e. they are placed on the respective rope and moved by means of a guide carriage (e.g. in the case of a track cable of a cableway or a catenary cable of a suspension bridge).
Using two or more direct-current coils or, as is the case with Dr. Brandt's standard, several permanent exciters, depending on the rope type and diameter, the rope is homogeneously magnetized in the longitudinal direction. Discontinuities or defective locations such as wire breaks, corrosion, points of wear or even wire braiding faults lead to the formation of a radial component of the magnetic field in addition to the axial component. The leakage flux of these inhomogeneities induces voltage peaks in the normally centered, two or more thin measuring coils surrounding the rope body, the magnitude and direction of which depend, among other things, on the characteristics of the discontinuity. The voltage pulses are processed in a downstream electronic unit and stored and assessed on a laptop using the Dr. Brandt evaluation software. For the additional, scaled down representation on paper of the inspection results over the length of the rope a plotter is also often used for documentation purposes. Aside from documentation, inspection and auditing purposes, the measuring charts and the digital storage of the inspection results are also used for comparison of the results ascertained over different inspection intervals during the entire service life or period of use of a rope.
Even for wire-reinforced conveyor belts, such as those used in the mining industry, a measuring arrangement that is functionally identical but will be tailored to specific belt shapes has been successfully employed by Dr. Brandt for decades.
In all cases, the magneto-inductive measuring head from Dr. Brandt reliably detects signs of corrosion, wear and breaks in the wire – without being influenced by plastic coatings, lubricants or oil paint coatings on the ropes.
The complete equipment for reliable non-destructive wire rope testing therefore includes the Dr. Brandt Rope Tester with a test block that can be folded away easily from the rope, with integrated permanent exciter and measuring coils as well as an electronic control and evaluation unit,
a laptop and, if desired, an output device for the presentation of the results on paper or for long-term archiving on various data storage media.
Dr. Brandt Rope Testers are available in two versions: For permanent stationary use, as well as for short-term mobile use in inhospitable weather or environmental conditions. If so requested, the measuring devices are available in intrinsically safe design, i.e. they may also operate in environments endangered by firedamp.
For the inspection of stationary ropes or cables such as catenary ropes on bridges, a winch-operated measuring carriage is often employed. Equipment and systems furnished by Dr. Brandt are exclusively of customized design and execution.
TCK.W by Dr. Brandt - Product Partner for Germany, Belgium
TCK.W - Wire rope inspection expert system
Innovative Inspection Technology
We’ve completely solved three existing issues: wire rope’s hidden danger, it’s waste and it’s low efficiency.
- Low magnetization for wire rope
- Inspection for broken wires, abrasion, erosion, fatigue and deformation (LF/LMA)
- Recognition and evaluation for splice displacement
- Accurate inspection for external flaws
- Recognition and evaluation of numbers of broken wires in the length of 6D and 30D
- Measuring wire rope diameter variation
TCK.Ws products have served 2500 clients in 42 countries
Four Core Capabilities:
- Efficient and accurate inspection capability for broken wires, abrasion, erosion, fatigue, splice displacement and other flaws
- Efficient and accurate identification capability for numbers of broken wires in the length of 6D and 30D
- Efficient and accurate measuring capability for wire rope diameter variation
- Efficient and accurate positioning capability for wire rope flaw verification
Ropes are the „lifeline” of any cable car. For some reason, almost all the other parts of the cable car are monitored and secured on a permanent basis, but not the cable itself. Therefore, there is always a risk of rope failures during operation due to long-term strength loss. The antiquated manual inspections including visual inspection and callipering are less efficient and limited, and current MRT methods for cableway rope cannot inspect flaws while the cableway is running. However, TCK.W Wire Rope Inspection Expert System is designed to replace manual inspection with intelligent inspection, and innovatively solves the challenges with real-time detection technology. In other words, TCK.W Wire Rope Inspection Expert System is the most advanced instrument in the world that conforms to European and American inspection requirements.
- Standard practice for electromagnetic examination of ferromagnetic steel wire rope (ASTM-E1571-2011)
- Cranes-wire ropes-care and maintenance, inspection and discard (ISO-4309-2004)
Our Advanced Portable Wire Rope Inspection Device, which operates on a „spatial magnetic field vector resultant“, -theory, adopts large airspace and controlled (weak) magnetic fields as its operating principle. Our device is capable of detecting LF and LMA defects (or flaws) more efficiently compared to conventional (strong) magnetic NDT devices and conforms to the ASTM -E1571-2011 standard.
Simple 4-step process:
- Magnetize the wire using the portable hand-held magnetizer
- Enter wire construction parameter
- Unique and innovative testing technology
- Highly sensitive sensor. (Patented)
- Automatic noise filtering capabilities
- Automatic system calibration
- Digital (LCD) display for instant operator review
- Accurate and precise flaw locating system
- Device includes self-diagnostic features
- Sample short part of the wire to determine the benchmark value
- Look the inspection device on the wire rope and start to measure
- Highly portable even in cramped spaces
- Low weight (2.8kg)
- Easy to learn and operate
- Easy to maintain and clean
- Automatic report generation
- Fast report storage and retrieval
- Capable of high-speed rope inspection up to 15 meter/second