RU2727559C1 - Portable electromagnetic scanner-flaw detector for non-destructive inspection of drilling pipes - Google Patents

Abstract

FIELD: measurement.SUBSTANCE: invention relates to measurement equipment for non-destructive testing of small-size pipes. Portable electromagnetic scanner-flaw detector for non-destructive inspection of drilling, tubing and casing pipes and external pipelines consists of two U-shaped electromagnets connected by hinges, system is installed in any place on pipe surface, poles of electromagnets cover the whole perimeter of pipe. Magnetization system is combined with system of sensors and is installed on motor bogie for movement along pipe.EFFECT: technical result is increased range of analysed pipe wall thicknesses, reduced weight, dimensions and power consumed by device, device installation anywhere in drill pipe or pipeline, detection of longitudinal defects of loss of continuity of metal in pipe walls at low-frequency remagnetization and, at the same time, demagnetization of pipe during device movement.1 cl, 5 dwg

Description

Portable electromagnetic scanner-flaw detector for non-destructive testing of drill pipes

The invention relates to measuring equipment for non-destructive testing of small-sized pipes and can be used to detect defects, metal loss and cracking in external small-sized pipelines.

The task of express inspection of pipes made of ferromagnetic materials in the places of their operation is important for many areas of industry and transport. This task can be solved by automated mobile devices for non-destructive testing of the material of the pipe walls by the magnetic method, with their help defects of the loss of metal continuity are detected [1-3].

Known mobile device company New Tech Systems, Inc. (USA, www.newtechsystems.com) - VEDAQ 2000-C for monitoring drill, tubing and casing pipes, containing: an electronic component cabinet, where an industrial computer is mounted, receiving signals from magnetic transducers and transforming these signals into files for viewing in real time in the environment of special software, the power supply of the magnetizing coil and the sensor system is also mounted in the electronic components cabinet; a trolley for moving the device along the drill pipe body; a system of magnetic transducers, consisting of Hall sensors and search induction coils, the system of magnetic transducers has the shape of a cylinder, inside along the axis of which a pipe is placed, for each size of a drill pipe its own system of magnetic transducers is made; magnetizing coil.

The device works as follows. The sensor unit is attached to the underside of the trolley and together with it is installed on the outside of the pipe. A magnetizing coil is placed on top of the cart.

The power supply of the parts of the device is carried out by cables from the alternator and from the cabinet of electronic components. During the movement of the trolley, the magnetic transducers record the signals of loss of continuity of the metal and transmit them through the network cable to the industrial computer. As a result, the device operator sees these signals in real time. The operator can stop the trolley of the device over the defect, additionally go through the problem area to determine the type of defect, loss of metal continuity. The device detects lateral defects of the drill pipe body and monitors their wall thickness.

The disadvantage of this device is: the magnetizing system of the device cannot be installed at any place in the pipe, the induction magnetizing coil is worn only from the end of the pipe and has large geometric dimensions and mass; the device is not able to control the zone of the welded joint of the drill pipe body with the joint; the device is not capable of detecting longitudinal defects of the loss of metal continuity in the pipe walls.

The weld zone of the drill pipe body to the tool joint is important for drill pipe inspection. At present, defects in the loss of metal continuity in it are determined using the magnetic particle method, which increases the inspection time and the role of the so-called "human factor" in pipe inspection.

There is a known mobile device developed at the Hefei University of Technology, containing an induction magnetizing coil, a basket in the form of a cylinder, where magnetic transducers are located (the device uses both Hall sensors and search induction coils), an electrically driven trolley to move the device along a controlled pipe, a block sensor signal processing, power supply for the induction magnetizing coil, device control unit and control data recording unit. Hall magnetic transducers allow the device to control the thickness of the pipe wall, search induction coils are used to detect transverse defects of the loss of continuity of the metal in the pipe wall [Chinese patent for useful model No. 201173911].

The disadvantages of this device include: inability to control the upset area (welded joint) of the drill pipe; inability to determine longitudinal defects of the loss of continuity of the metal in the pipe wall; the device is installed only from the end of the pipe; the lack of a device for demagnetizing the pipe after testing.

Known mobile device "Magportabur", developed by CJSC "Vimatek", containing an induction coil operating on direct and low-frequency alternating current; magnetic transducer system, magnetic transducer system consists of induction search coils and Hall sensors; a trolley with an electric drive for moving the device along the controlled pipe; sensor signal processing unit; induction coil power supply; device control unit and control data recording unit [RF patent for utility model No. 158546].

Disadvantages of the device: the magnetization system is installed only at the end of the investigated pipe; the device cannot control the zone of the welded joint of the drill pipe body with the joint (upset zone); the device does not detect longitudinal defects.

The closest in technical essence to the claimed invention is an electromagnetic portable control system for drilling, tubing and casing ARTIS-3 (prototype) [US patent No. 5943632]. The ARTIS-3 pipe monitoring device consists of the same functional parts as the previously described VEDAQ 2000-C, however the ARTIS-3 device sensor system uses only magnetic Hall transducers, and the ARTIS-3 sensor system uses three times more transducers Hall, namely 25 converters. A larger number of Hall transducers made it possible for the ARTIS-3 device to achieve a more reliable control of the entire pipe surface; automated mathematical processing of the received signals allows working with both smaller defects and extended smooth defects that cannot be detected by search induction coils [4]. Full automation of the ARTIS-3 device allows detecting defects in one pass of the trolley with a sensor system; this device does not have to stop in the problem area for additional information.

The disadvantages of the ARTIS-3 prototype device include:

- a magnetizing system, consisting of an induction coil, which is installed only from the end of the pipe;

- the minimum inner diameter of the coil is limited by the outer dimensions of the drill pipe joint, thus the coil can either magnetize a small range of pipe wall thicknesses, or it will have a significant mass;

- the magnetizing system consumes a large amount of electricity;

- the device is not capable of detecting longitudinal defects of the loss of metal continuity in the pipe walls;

The claimed invention and the prototype have the following general technical features: a motorized trolley for moving the systems of the device along the investigated pipe; an electronic component cabinet containing an industrial computer, magnetizing system power supplies and sensor systems; moreover, the sensor system of the device uses only magnetic Hall transducers.

The proposed invention differs from the prototype in that:

- Uses a magnetization system deployed on four hinges, combined with a sensor system;

- the magnetizing system uses two U-shaped electromagnets, capable of operating with direct and low-frequency alternating electric current;

- the poles of the U-shaped magnets are in the form of half rings;

- the poles of the magnetizing system are made up of steel plates, separated by an electrically insulating layer, which allows the system to transfer to the investigated section of the pipe the magnetic flux created by a low-frequency electric current, this magnetic flux causes eddy currents flowing around the circumference, the magnetic field from which allows simultaneously demagnetizing the pipe and detect longitudinal defects of loss of continuity of metal in the pipe wall;

- in the blocks of the sensor system there are two lines of magnetic transducers for measuring the tangential and normal components of the magnetic field.

In the claimed invention, the disadvantages of the prototype are eliminated as follows:

- a magnetizing system consisting of two U-shaped electromagnets and opening on four hinges can be installed anywhere in the pipe;

- two U-shaped electromagnets can magnetize a greater thickness of the pipe wall with a smaller mass of the magnetization system, which consumes less electricity;

- to determine longitudinal defects, magnetization of the pipe with a low-frequency alternating current is used, eddy currents formed in the pipe wall, flowing around the pipe circumference, which make it possible to detect longitudinal defects of the loss of metal continuity.

The invention is based on the solution of the following technical problems:

- increasing the range of investigated pipe wall thicknesses;

- reduction in weight, size and power consumption by the device;

- installation of the device anywhere in the drill pipe or pipeline;

- detection of longitudinal defects of the loss of metal continuity in the pipe walls during low-frequency magnetization reversal and, at the same time, demagnetization of the pipe during the movement of the device.

The essence of the claimed invention lies in the fact that a portable electromagnetic scanner-flaw detector for non-destructive testing of drilling, tubing and casing pipes, as well as aboveground pipelines has been developed. The device consists of a motorized cart and a magnetization system combined with a sensor system, an electronic component cabinet containing an industrial computer and power supplies for all scanner-flaw detector systems. The trolley is installed on the pipe surface and moves along the pipe surface using an electric motor. The magnetizing system consists of two U-shaped electromagnets connected by four hinges. Swing electromagnets are installed on a trolley and are capable of magnetizing the pipe wall with both a constant and low-frequency alternating field. The system of sensors is combined with the poles of the electromagnets and, when the device is installed on a pipe, covers the entire perimeter of the pipe. The sensor system consists of spring-loaded blocks in which the lines of Hall magnetic transducers are located. During the movement of the scanner-flaw detector, magnetic Hall transducers record magnetic fluxes of leakage from defects in the pipe wall.

Implementation of the invention.

The composition of the claimed device, the process of its installation and operation is illustrated using the drawings shown in Fig. 1-5.

FIG. 1 shows a sketch of the proposed device:

1 - electric motor;

2 - pole of the U-shaped electromagnet (part of the magnetic circuit);

3 - spring-loaded sensor system unit;

4 - pipe wall;

5 - magnetic circuit;

6 - hinge;

7 - trolley wheel.

FIG. Figures 2-3 show sketches of the stages of installing a flaw detector on a drill pipe; extenders are attached to the poles of the electromagnets to increase the magnetic flux transmitted into the pipe.

The magnetizing system consists of two U-shaped electromagnets connected by four hinges (Fig. 4):

2 - pole of the U-shaped electromagnet (part of the magnetic circuit);

5 - magnetic circuit;

6 - hinge;

8 - electromagnet magnetizing coil.

FIG. 5 shows a sketch of the sensor system in the open state:

3 - spring-loaded sensor system unit;

9 - a line of magnetic Hall transducers;

10 - signal conversion board of analog-to-digital converter / digital-to-analog converter.

The system of sensors consists of 8 blocks in each of which there are 16 magnetic Hall transducers (two rows of sensors with 8 Hall sensors in each for measuring the tangential and normal components of the magnetic field strength). Each block is spring loaded, allowing it to slide over uneven pipe surfaces. A layer of wear-resistant plastic protects the surface of the magnetic transducers that slide over the pipe surface.

The physical essence of the use of the claimed portable electromagnetic scanner-flaw detector is that:

- the magnetizing system uses two small coils to create a magnetic field flux, which is transmitted through the magnetic circuit to the investigated section of the pipe surface, creating a uniformly magnetized region in it, the magnitude of the magnetic induction in this area is 1.6-1.7 T with a pipe wall thickness of up to 15 mm, which allows to obtain reliable signals of the magnetic field of stray from defects of the loss of continuity of the metal in the pipe wall. The small dimensions of the magnetizing system, namely the coils with a magnetic core, provide a lower weight of the system and, therefore, lower power consumption, while simultaneously being able to magnetize a larger range of pipe wall thicknesses (up to 15 mm) to the desired value. The swiveling method of installing the system on the pipe surface allows the device to be installed anywhere on the outer surface of the pipe. The magnetic core of the magnetization system is made up of steel plates separated by an electrically insulating layer, which allows the system to neutralize the influence of the skin effect and transfer the magnetic flux created by a low-frequency electric current (1-3 Hz) to the investigated section of the pipe. An alternating magnetic field demagnetizes the pipe. An alternating magnetic field creates eddy currents in the pipe walls that flow around the circumference of the pipe. Eddy currents flow around longitudinal defects, thus creating changes in the magnetic field. From the recorded changes in the magnetic field of eddy currents, longitudinal defects of the loss of metal continuity are determined.

The sensor system uses 128 magnetic Hall transducers, which take 400 measurements per second. The amount of information received about the magnetic field above the pipe surface provides a good sensitivity of the device, a large number of sensors and mathematical processing of the signals they receive allows achieving high resolution. The design of the sensor system makes it possible to monitor several similar standard sizes of pipes, as well as to drive into the area of the welded joint of drill pipes.

Technical results:

- increasing the range of investigated pipe wall thicknesses;

- reduction in weight, size and power consumption by the device;

- installation of the device anywhere in the drill pipe or pipeline;

- detection of longitudinal defects of the loss of metal continuity in the pipe walls during low-frequency magnetization reversal and, at the same time, demagnetization of the pipe during the movement of the device.

Claims (1)

Portable electromagnetic scanner-flaw detector for non-destructive testing of drilling, tubing and casing pipes and external pipelines, designed to be located on the outside of a pipe or pipeline and move along the pipe generatrix, including an electronic component cabinet containing an industrial computer and power supplies for all scanner systems - flaw detector, as well as a motorized trolley for moving along the surface of the pipe, combined with a magnetization system deployed on four hinges, which includes two U-shaped electromagnets operating on direct and low-frequency alternating electric current, and the metal parts of the electromagnets are made up of steel plates separated from each other electrically insulating layer, and the magnetizing system is combined with the sensor system, which consists of spring-loaded blocks, each of which contains a line of magnetically sensitive transducers.

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