Multichannel device CORSAIR-16 is intended for electromagnetic control of metallic items when access from just one side is available. The device carries out detection and quantitative assessment of metal loss (walls thinning and pitting corrosion of various origins). CORSAIR-16 allows inspection of boilers heating surfaces, process furnaces, bottoms and walls of storage tanks, pipelines
and vessels.

CORSAIR-18 FEATURES:

• A single device for inspection of storage tanks bottoms, pipelines (from
  the outer side) and in-line inspection;
• Non-contact inspection through a gap and/or coating of up to 9 mm;
• No surface grinding/cleaning needed (unless in case of in-line inspection)
• Uniform rust, scale, as well as water inside a non-ferrous vessel or pipe,
  do not affect inspection results;
• Comparative evaluation of the detected defects;
• Detection and differentiation of inner and outer defects in one run;
• No blind zones in the course of testing;
• Absence of permanent magnets: alternating magnetic field is created by
  excitation winding of the electromagnet. Due to this the transducer does
  not gather magnetic particles, does not cause magnetization and does
  not lose its properties with time;
• Wireless on-line data transfer to a laptop via Bluetooth;
• Signal value (strength) depends on the speed of transducer movement –
  so this speed should be relevantly constant;
• Wide frequency range: from 1 to 30 000 Hz;
• The device can be calibrated with the application of test blocks.

TYPES OF TRANSDUCERS:

Depending on test objects characteristics and inspection tasks the
user may apply different specialized multichannel electromagnetic
transducers:

• Transducer with flat working surface – for inspection of storage tanks or pipelines of more than 700 mm in diameter. The transducer is installed onto a wheelbase allowing steady movement and setting a correct gap between the transducer and the object;
• Concave surface transducers (to fit the pipeline diameter) – for pipeline inspection from the outside. The transducer is installed onto a wheel base allowing steady movement and setting of a correct gap between the transducer and the object..
• In-line cylindrical transducers – for in-line inspection (e.g. pipes of heat exchangers);
• Eddy current transducers for balanced field – for inspection (crack detection) of welds, weld proximity zones and core metal parts.

DATA PRESENTATION

Working data is presented on a laptop or tablet screen in the form of A-Scan amplitude, A-Scan phase or C-Scan

The A-Scan window synchronously displays lines of time mappings for amplitude and phase of the signals received from the transducer probes. The resulting grid of lines on the screen represents a 3D model of the reverse side of the inspected item wall. Areas of growth or short bursts of signal values indicate metal thinning or pitting corrosion. The С-Sсаn window presents the data obtained through the A-Scan as a color coded plan.

The received data is saved as a file. After that, using on-screen cursors, the user can obtain estimated quantitative data on the size of metal thinning and pitting corrosion. To obtain quantitative data of enhanced precision it is necessary to execute calibration on a control sample.

The screenshot presents visualization of detecting a local metal thinning (diameter – 12 mm, depth equals 40% of the initial steel wall thickness, working gap – 4 mm).

CORSAIR-16: OPERATING PRINCIPLE

Electromagnetic principle of the device operation is based on the interaction between alternating magnetic field and metal. The system can operate in a wide frequency range: 1 – 30000 Hz.

During the application of the lowest frequencies (5 – 30 Hz) eddy currents inside a metal object are negligible, so at such frequencies the system operates as a low-frequency electromagnetic one. When the low-frequency electromagnetic method is applied, the transducer receives effective signal by means of identifying smaller and larger zones where there is alteration of the value of the magnetic field energy that is absorbed by the tested metal in combination with curvatures and redistributions of the magnetic flux during cyclic reversal magnetization.

In other words, signal of a defect appears in the zones of alterations in the resistance (inertia) of the tested metal towards cyclic reversal magnetization due to the decrease in the “magnetic mass” at the area of pitting corrosion and metal thinning. The device produces what can be described as “magnetic swing” of metal, calculates the mass of “magnetic pendulum” under the sensitive element of transducer channel, presenting it in the form of alteration in the amplitude and phase of this channel signal. The system will also indicate an increase in “magnetic mass”, which would mean wall thickening or passing of a pipeline support structure during in-line inspection.

Low frequency electromagnetic method (5 – 30 Hz) is applied only for ferromagnetic objects. Thanks to the wide range of operating frequencies of the device (0 – 30 000 Hz) at frequencies above 1 000 Hz the system can operate as an eddy current one, enabling the inspection (cracks detection) of non-ferromagnetic items.