RU2736143C1 - Device for magnetometric diagnostics of ground pipelines and tanks without removal of insulating coating - Google Patents

Abstract

FIELD: technological processes; measuring.

SUBSTANCE: invention relates to repair of steel pipelines and can be used for magnetic diagnostics of steel pipelines without removal of insulating coating. Device contains identical measuring channels of magnetic field, containing sensors of magnetic field, located linearly parallel to longitudinal axis of pipeline. Each channel has an amplifier, a low-pass filter, and also comprises a common ADC, a controller, a wireless communication device, an information display unit and a memory unit. Output of each magnetic field sensor is connected to input of amplifier, output of which is connected to low-pass filter, output of which is connected to ADC input, which output is connected to controller, which output is connected to wireless communication device, first output of which is connected to input of information display device, controller second output is connected to memory unit. Magnetic field sensors used are magnetoresistive transducers which do not require preliminary magnetization of the controlled surface.

EFFECT: invention allows improving diagnostics accuracy, enlarging the scope of application, considerably reducing dimensions and power consumption of the device, as well as providing the possibility of continuous monitoring of pipelines without removal of heat-insulating coating with thickness of up to 150 mm.

1 cl, 4 dwg

Description

The device relates to the study of coated surfaces, for example, for magnetic diagnostics of steel pipelines without removing the insulating coating.

The proposed technical solution relates to devices for magnetic diagnostics of ground pipelines of industrial sites, pipelines of ground utility networks, heating mains, as well as underground pipelines in pits, regardless of the diameter of the pipeline.

Known magnetic flaw detector containing a split frame, consisting of a base and two half frames, equipped with hinges. The frame is in contact with the surface of the pipeline by drive wheels connected to the longitudinal motion geared motor, support and pressure wheels and roller bearings. Two magnetic modules with blocks of magnetic field sensors, one of which magnetizes the pipeline wall in the longitudinal direction, and the other in the transverse direction, are fixed through suspensions on a toothed ring consisting of two half-rings connected by a loop assembly. The ring is mounted on the roller bearings of the frame and is connected to a geared motor for the drive of the circumferential movement. A longitudinal motion odometer, a power plant are installed on the frame, electrically connected to the control unit for the longitudinal and circumferential motion drives. On the toothed ring there is an odometer of a circular movement, an information storage unit connected to magnetic field sensors and odometers, and a power supply unit (see, patent RU 2295721 G01N 1/00).

The disadvantage of this technical solution is the large mass of equipment, the need to have replaceable frames for pipelines of various diameters, high energy consumption associated with the need to pre-magnetize the metal.

Known magnetic flaw detector of cylindrical objects (and.with. SU 1161859, G01N 1/00), containing a magnetizing system, measuring transducers (sensors), a registration unit, and a trolley made in the form of a self-propelled chassis. In this device, a flaw detector is installed on the controlled surface, oriented along a given direction, a predetermined value of the gap between the pole of the magnetizing system and the controlled surface is set, the flaw detector is moved along the controlled surface and the fluxes of magnetic field leakage from defects are recorded using a measuring transducer.

This flaw detector has a large mass, as a result of which it has an unstable position of the supports. Also, it is impossible to diagnose onshore pipelines of industrial sites with small bending radii, as well as in the presence of closely spaced structures.

A device for non-contact diagnostics of steel pipelines is known, containing at least two sensors of identical sensors for measuring the magnetic field, installed at a distance from 1 to 10000 m from each other on the pipeline axis, means for synchronizing sensors, means for recording changes in the magnetic field strength caused by stray currents, and data processing means. The disadvantage of this device is the impossibility of precise localization of the defect, since it will only be known that the defect is somewhere between two magnetic field sensors (see, patent RU 2506581, G01N 1/00).

A device is known for external non-destructive testing of pipe walls (detection of defects, metal loss, cracking in pipe walls) directly during repair work when replacing pipeline insulation. The device contains a magnetic search system, which includes a spring-loaded block of transducers with measuring sensors that measure the stray magnetic field above the surface of the test object, a magnetization block, an electronics block and transport elements. In addition, the magnetic search system has a device for blocking the magnetic field, which makes it possible to easily remove the flaw detector from the object under study after the end of the work. The transducer block includes two-dimensional encoders, which are structurally manufactured as a single unit with a transducer block and a spring-loaded suspension, (see, and.s. SU 2563601).

The disadvantage of this device is the ability to work only with completely removed pipeline insulation during repair work, which limits the scope of the device, as well as the need to carry out preliminary magnetization of the controlled surface, which significantly increases the power consumption, weight and dimensions of the device.

The closest in essence and the achieved technical result is a device for eddy-current magnetic flaw detection of ferromagnetic objects to detect defects in surface and subsurface objects. The device contains a source of a constant magnetic field, a line of eddy-current transducers between its poles, parallel to the poles, and a unit for adjusting the magnetizing constant field. The adjustment unit is made in the form of a frame and a subframe, connected with the possibility of rotation about the axis of rotation directed along one of the sides of the frame and perpendicular to the line of the transducers, as well as the subframe clamps relative to the frame with a given angle between their planes. The system provides the creation of a magnetic field monotonically changing along the line of transducers. The disadvantage of this device is the need for preliminary magnetization of the controlled surface and cleaning the surface from the insulating coating. Eddy current magnetic field transducers react only to crack-like defects, and with large losses of sensitivity to corrosion defects, and do not react at all to other stress concentrators associated with metal delamination, dents, corrugations, etc. (see, a.c. SU 2566416).

The technical result of the invention is to improve the diagnostic accuracy, expand the scope, significantly reduce the size and power consumption of the device, increase the productivity of the equipment, as well as the possibility of continuous (continuous) control of pipelines without removing the thermal insulation coating up to 150 mm thick.

The essence of the invention consists in the use of linearly located magnetic field sensors of the magnetoresistive type with a step of 2.5 cm, moreover, 16 sensors are located in one section of the device, with the possibility of increasing the coverage area by docking the required number of sections (up to 4). The working position of the device is parallel to the generatrix of the pipeline, while the device moves around the circumference, which allows the device to be used on pipelines of any diameter without transforming the system. The data is transferred to the memory unit and information display using a wireless communication system, which eliminates the presence of cables. The collected information is displayed on the information display device in the form of a color pattern, in which each color corresponds to a certain level of magnetization of the pipeline surface.

The novelty of this technical solution consists in the use of highly sensitive magnetoresistive magnetic field transducers, which make it possible to inspect the surface without preliminary magnetization and removing the insulating coating; in the presentation of data not in the form of a magnetogram for each sensor, which complicates the general understanding of the distribution of the magnetic field over the controlled surface, but in the form of a color picture, in which each color corresponds to a certain value of the surface magnetization; in the possibility of increasing the coverage bandwidth by docking additional measuring units; in the ability to control pipelines and tanks of any diameter without adapting the measuring system; in the use of wireless communication between the measuring unit of magnetic field sensors with the unit for displaying and storing information, which greatly facilitates the production of field work.

The invention is illustrated in the drawings.

Figure 1 shows a block diagram of the device, where:

1 - magnetic field sensor;

2 - amplifier;

3 - low-pass filter;

4 - ADC;

5 - controller;

6 - wireless communication unit;

7 - information display device;

8 - memory block.

Figure 2 shows a picture of the distribution of the magnetic field of the pipeline surface in a section of 50 × 50 cm. A longitudinal seam and areas of increased magnetization associated with pitting corrosion of more than 50% of the wall thickness in the near-weld zone are visible.

Figure 3 shows a view of the measuring unit of the device (unit of magnetic field sensors).

Figure 4 shows the layout of the sensor unit on the surface of the controlled pipeline, where:

9 - pipeline with heat-insulating coating;

10 - block of magnetic field sensors;

11 - swath width;

12 - thermal insulation;

13 - direction of movement during surface control.

The device works as follows.

The device contains 16 identical channels for measuring the magnetic field.

Each channel is structured as follows.

As a primary sensor (transducer) of the magnetic field (1), a Honeywell HMC 1053 magnetoresistive magnetic field meter is used. The signal from the magnetic field sensor is fed to an amplifier (2) based on an AD 8642 microcircuit, then to a low-pass LC filter (3 ), designed to increase the noise immunity of the device when operating under a strong electromagnetic background of industrial sites, after which the filtered signal is fed to the ADC (4), which is an ADS 1115 microcircuit, from the output of which the signal is fed to the input of the controller (5) of the Atmega 326P type , from the output of which the signal is fed to the device (6) of wireless communication of the HC-06 type, from the output of which the signal is fed to the information display device (7) LM 4228 and the memory unit (8) KNPS. 467669.01.

The design of the device is as follows.

Magnetic field sensors installed linearly one behind the other with a step of 2.5 cm, perpendicular to the direction of movement of the antenna unit along the controlled surface, perceive the surface magnetic field, as a result of which a picture of the surface magnetic field distribution is displayed on the screen of the information display device.

Claims (1)

A device for magnetic diagnostics of steel pipelines without removing the insulation coating, containing a common ADC, a controller, a wireless communication device, an information display unit, a memory unit, identical measuring channels of a magnetic field with magnetic field sensors located linearly parallel to the longitudinal axis of the pipeline, with each said measuring the channel contains an amplifier and a low-pass filter, while the output of each magnetic field sensor is connected to the input of the amplifier, the output of which is connected to a low-pass filter, the output of which is connected to the input of the ADC, the output of which is connected to the controller, the output of which is connected to a wireless communication device, the first the output of which is connected to the input of the information display device, the second output of the controller is connected to the memory unit, characterized in that magnetoresistive transducers are used as magnetic field sensors that do not require pre-magnetization of the controlled surface xnosity.

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