Working principle of MFL flaw detectors:
► Magnetic field: A flaw detector is placed inside the pipeline, which generates a magnetic field by propagating it along the pipe wall. A permanent magnet or electromagnet is used for this purpose.
► Magnetic flux distortion: When a defect (such as corrosion or a crack) is present in the pipe wall, it causes a localized disturbance of the magnetic flux - its leakage or “magnetic flux leakage.” This occurs because the defect disturbs the material structure and alters the magnetic field.
► Scanning and Measurement: Sensors on the flaw detector detect magnetic flux leakage, and then the data is transmitted to an analyzer, which interprets it and displays information about the location and size of the defects.
► Data Interpretation: Changes in magnetic flux are analyzed to accurately identify the type and extent of the defect, as well as to assess the extent of deterioration of the pipe or potential hazard areas.
Advantages of MFL flaw detectors:
► High sensitivity: These devices can detect even small anomalies that may not be visible with other inspection methods.
► Deep penetration: They are effective for diagnosing pipelines of various diameters, including those with thick walls.
► Rapid Diagnostics: MFL flaw detectors are able to work quickly, allowing large sections of the pipeline network to be inspected in a relatively short amount of time.
► Less damage to pipes: The method does not require drilling or breaking the pipe, minimizing the chance of further damage.
► High accuracy: The software can accurately determine both the location of the defect and its size, which is important for planning further work (e.g. replacement or repair).
At ZOGPI, such devices are designed to meet high requirements for reliability, accuracy and durability, allowing them to be used with confidence for diagnostics in the most demanding operating environments.
Working principle
of TFI flaw detectors:
► Magnetic field: Unlike methods that utilize a permanent or radial magnetic field, TFI flaw detectors generate a transverse magnetic field that acts perpendicular to the pipe axis. This transverse field generates a wider and more uniform distribution of magnetism across the pipe wall.
► Distortion of magnetic flux: When there is a defect in the pipe wall (such as a crack or corrosion), it disturbs the transverse magnetic field. The defect acts as an obstacle to the normal distribution of magnetic flux, resulting in leakage or distortion of the magnetic field. Sensors detect these changes and use the data for analysis.
► Defect Detection: Sensors on the TFI flaw detector measure magnetic flux leakage and transmit the data to the analyzer, which interprets the information to determine the location and size of the defects.
► Data interpretation: A key feature of the TFI is its ability to accurately detect longitudinal and transverse cracks, making it an effective tool for identifying critical faults in pipelines.
At ZOGPI, as well as other leading manufacturers, TFI flaw detectors are used for regular inspections of pipeline systems in order to improve operational reliability and prevent accidents.
Advantages and application
of TFI flaw detectors:
► Detection of longitudinal and transverse cracks: This is one of the main types of defects that can be difficult to detect with other methods, such as radial magnetic fields. TFI devices allow for more accurate detection of such defects.
► Corrosion sensitivity: These devices are well suited for detecting anomalies related to metal loss due to corrosion, as the transverse field covers the entire thickness of the pipe wall, providing a more complete analysis.
► Deep penetration: Similar to MFL flaw detectors, TFI systems are capable of scanning large-walled pipes and finding defects at different levels of material thickness.
► High accuracy: Thanks to the cross-field, TFI flaw detectors provide precise defect localization, which is important for planning pipe repair or replacement.
► Fewer false alarms: Because the transverse magnetic field creates a more stable and uniform distribution, these flaw detectors have a lower false alarm rate than other methods.
► Applications of TFI flaw detectors: TFI flaw detectors are ideal for the diagnosis of pipelines operating in aggressive environments where defects such as stress cracks or corrosion can occur. They are actively used on pipelines in the oil and gas, chemical and power industries, as well as for integrity monitoring of pipes operating under high pressure.
Caliper operating principle:
► Principle of measurement: Caliper flaw detectors operate using a series of sensors or mechanical devices that measure the internal diameter of the pipe at different sections along its length. They are able to detect even small changes in the pipe geometry such as axial curvature, ovality, deformations from external influences or overpressure.
► Working part: Inside the flaw detector is a series of spring-loaded or mechanical probes that scan the inside of the pipe as it passes through the pipe. These probes accurately measure the radius of the pipe at various points and transmit the information to the analyzer.
► Data processing: The data received from the probes is transmitted to a system that analyzes changes in the shape and size of the pipe, comparing it to a reference. This allows for the detection of any abnormalities such as constrictions, dilations or other deformations that may indicate damage.
► Interpretation: Based on the collected data, a graph or 3D model of the pipe is constructed that shows all defects and changes in geometry. The system can also provide the exact coordinates of damage locations or anomalies for subsequent repair.
► Detection of geometric anomalies: Caliper flaw detectors are ideal for detecting changes in pipe geometry such as potholes, dents, axial distortion or ovality. These defects can occur due to mechanical damage, external factors or aging of the material.
► High accuracy: By utilizing sensitive sensors and precise measurements, this type of flaw detector provides high accuracy in determining the shape and size of the pipe.
► Early detection of problems: These devices can detect defects that may not be visually apparent, such as loss of shape or over-expansion of the pipe due to pressure, corrosion or other factors.
► Versatility: Caliper flaw detectors can be used for different pipe types and materials, including pipes with different wall thicknesses, making them a versatile tool for diagnosing pipeline systems in a variety of industries.