RU2684949C1 - Method and device for method of magnetic control - Google Patents

Abstract

FIELD: pipelines.SUBSTANCE: group of inventions relates to the nondestructive inspection of pipelines. Method for the magnetic monitoring method further comprises steps of moving the diagnostic robot in steps, where the length of each pitch is equal to the width of the variable magnetic field sensor capture, at that, during rotation of the rotation assembly, the amplitude of the variable magnetic field is fixed for at least two different frequencies in each point of the monitored surface with the possibility of estimating the depth of the defect and determining its position by associating signal amplitudes to the longitudinal and angular coordinates.EFFECT: technical result is higher accuracy of detecting defects of pipelines.3 cl, 2 dwg

Description

TECHNICAL FIELD

The claimed technical solution relates to the field of technology of non-destructive monitoring of the state of pipelines, in particular non-contact magnetic methods of in-line diagnostics, and can be used to detect defects in pipelines of complex shape and small diameter.

BACKGROUND

It is known in the art that when using various diagnostic equipment, such as scanners or in-tube shells, during in-line diagnostics defects are revealed, both through, forming a through hole in the pipe wall, and surface defects of small depth (usually less than 1 / 3T, where T - pipe wall thickness), etc. In addition to these types of defects, there are various structural elements on the pipes, such as welds, cladding, patches, etc. In some cases, when conducting in-line diagnostics, structural elements may give signals similar to those from defects.

A device for determining pipeline defects (RU 156827) is known. The device contains a node creating a magnetic field, a converter for changing the magnetic field into an electric voltage, a drive mechanism, as well as control and processing units. At the same time, the node creating the magnetic field is made in the form of an alternating current source, the outputs of which are connected to the ends of the pipe section to be tested, the converter of changing the magnetic field into electric voltage includes inductors connected to the processing unit and provided with units of rotation connected to the processing and control units coils around the axis of the pipe and maintaining a constant gap between them and the inner surface of the pipe, as well as the display of the controlled area of the pipe survey associated with the monitor a video camera, while the drive mechanism is equipped with an emergency removal system connected to the control unit of the device part placed in it and connected to a transducer of changing the magnetic field into electrical voltage by means of a pivot-universal joint.

It is also known a vehicle for moving a robot in a pipeline of complex configuration (RU 170056), containing a base with an electric motor mounted on it, three identical wheel pairs arranged relative to each other at an angle of 120 °, a mechanism for transmitting movement from the electric motor to the propulsion unit and an adaptation mechanism preloaded wheels to the surface of the pipeline, characterized in that the propeller is made in the form of a belt, made with a tread on the outside, touching during operation of the device surface and the pipeline, side and gear profile corresponding to the profile of the gear rim of the drive wheel, on the inside, which together with the gearbox is a mechanism for transferring movement from the electric motor to the propulsion unit. This mechanism and the electric motor are located in the front, in the direction of the vehicle, its part, made with the possibility of swinging on the axis of rotation of the roller, framed by a belt together with the drive wheel and located in the rear part of the tension roller. In the adaptation mechanism, the wheels are pressed to the surface of the pipeline, a clip sensor is connected, the output of which is connected to the robot control unit.

According to its technical characteristics, close to the claimed, for the prototype, a method and a device for monitoring the uneven wall thickness of inaccessible pipelines (RU 2596862) are chosen to control the state of the walls of pipelines without opening them. Essence: an alternating electric current is passed through the pipeline in the longitudinal direction. The magnetic field created by alternating current is measured at a constant distance from the inner wall of the pipe in its internal cavity, moving along it with stops for a time of complete rotation around the pipe axis at the same time at several points located on the longitudinal pipe sections when turning around its axis. According to the measurement, the arithmetic average value of the magnetic field induction is calculated at each place where the longitudinal movement is interrupted. The change in wall thickness at the points of the cylindrical surface of the pipe is established as a function of direct proportionality from the ratio of the average value of the magnetic field induction inside the pipeline of each interruption of the longitudinal movement to its value at the measurement points with a proportionality factor equal to the predetermined thickness of the defect-free pipe section. Technical result: increased accuracy, the ability to control the inside of the pipe without introducing disturbances in the process of measuring corrosion and sludge deposits and other defects.

The disadvantages of the above technical solutions is:

- measurement algorithm, which leads to the fact that, if there are large areal defects on the pipe, with a length exceeding the averaging interval, they may not be recognized by this algorithm, which affects the detection of defects and, as a consequence, a decrease in the reliability of information.

- with the presence of structural elements, such as weld, surfacing, patch, there is a "false response" of the system, which entails the unreliability of the results.

The objective of the proposed technical solution is the creation of a method and device for implementing a magnetic control method that provides an algorithm for processing data that excludes "false alarms" of a system on structural elements, such as a weld, surfacing, a patch.

DISCLOSURE OF THE NATURE OF TECHNICAL SOLUTION

The technical result of the proposed technical solution is achieved by creating: a method implementing the magnetic control method, which includes the scanning process by a diagnostic robot, which moves inside the pipeline along the monitored section with the possibility of performing a full turn with the help of the rotation unit and the movement of the diagnostic robot steps, where the length of each step is equal to the pickup width of the variable magnetic field sensor, while during the rotation of the node rotation, the amplitude of the alternating magnetic field is fixed for at least two different frequencies at each point of the test surface, ensuring that the depth of the defect can be estimated and its positions determined by tying the amplitudes of the signals to the longitudinal and angular coordinates. The specified technical solution provides an algorithm for data processing, eliminating the "false actuation" of the system on structural elements, such as the weld, surfacing, patch.

The device for the magnetic control method according to claim 1, which includes a magnetic control module placed on the rotary node of the diagnostic robot and characterized in that the module is equipped with at least one retractable manipulator with sensors of alternating magnetic field on it at least from one inductance coil, and the drive of each manipulator is controlled by signals from the gap meter located in the variable field sensor. The specified technical solution ensures the achievement of the method for the method of magnetic control.

A variant of the technical solution of the device is possible, characterized in that the remote-controlled diagnostic robot is equipped with a tracked drive. The specified technical solution ensures the delivery of a magnetic control device to the controlled section of the pipeline.

BRIEF DESCRIPTION OF THE DRAWINGS

Although the present technical solution is described on the example of a specific embodiment, various changes and modifications are possible within the scope of the present technical solution defined by the formula.

FIG. 1 is a schematic representation of a device for implementing the method of a magnetic control method.

FIG. 2 shows an example of the implementation of the proposed technical solution, in the form of a graph of the distribution of the amplitudes of the two-frequency signal in the defective zones (section A-A of FIG. 1).

Pos. 1 - probe current generator;

Pos. 2 - delivery vehicles, which is a remote-controlled diagnostic robot;

Pos. 3 - diagnostic module magnetic control;

Pos. 3a - retractable arm;

Pos. 4 - control computer;

Pos. 4a - wire connecting the generator to the pipe;

Pos. 4b - wire connecting to the control computer;

Pos. 5 - pipe;

Pos. 5A - controlled section of the pipe;

Pos. 6 - remote-controlled diagnostic robot;

Pos. 7 - rotation unit.

IMPLEMENTATION OF TECHNICAL SOLUTIONS

A device for implementing the magnetic control method consists of:

- probe current generator 1, which is a powerful (4 kW) low-frequency electrical oscillation generator (50-1000 Hz) with a low-impedance load. The probe current generator 1 is connected to the pipe 5 by means of high-current cables so that the connection points are at the beginning and end of the monitored section 5a of the pipe 5.

- delivery vehicles 2, which is a remote-controlled diagnostic robot 6, which allows you to move in the pipe 5 at a given speed.

- diagnostic module of magnetic control 3. This module 3 is a device placed on the rotating unit 7 of diagnostic robot 6. Module 3 is equipped with two retractable manipulators 3a, each of which is placed on the sensor of an alternating magnetic field consisting of 12 inductors. The drive of each manipulator 3a is controlled by signals from a gap meter located in an alternating field sensor (not shown). Thus, the constancy of the size of the gap between each sensor and the pipe wall in the process of in-line diagnostics, in practice at least 10 mm, is ensured.

- control computer 4 and communication lines 4a. Designed to control the process of control, as well as recording and analyzing the results obtained in the process of conducting in-line diagnostics.

- pipe 5, where the method of magnetic control is carried out, as a rule, on the controlled section 5a, with a size of more than 400 meters (from practice).

- remote-controlled diagnostic robot 6, this robot is equipped with a tracked propulsion, control and surveillance systems that allows you to maneuver in the pipe 5, passing tees and bends.

- rotation unit 7 - is a special docking unit, with the possibility of rotation in a clockwise direction and with which a remote-controlled diagnostic robot is equipped 6.

IMPLEMENTATION OF TECHNICAL SOLUTION

Diagnostics using the magnetic control method is performed in the following order:

- the generator of the probing current 1 is connected to the controlled section of the pipe 5a. The connection to the pipe is made at the beginning and end of section 5a using sensors.

- the diagnostic robot 6 is loaded into the pipe 5, namely onto the controlled section 5a, with the magnetic control module 3 installed on it. Module 3 is transferred to the diagnostic position by extending the manipulators 3a and activating the system for maintaining the gap between the sensor (not shown) and the pipe wall 5 ;

- turn on scan mode:

during the scanning process, the diagnostic robot 6 moves along the pipe 5 in a controlled area 5 in steps, with the length of each step being equal to the pickup width of the alternating magnetic field sensor (gap maintaining system). Moving to the next step, the output of the probe current generator is tuned to the frequency F1, the robot starts the rotation of the rotation unit 7 at an angle of 180 degrees. When rotating the rotation unit 7, each of the two sensors of the alternating magnetic field moves along the surface of the inner wall of the pipe 5 with a fixed gap supported by the gap support system. In the process of movement, each of the 12 inductors located in the sensor on the drive of each manipulator 3a, fixes the amplitude of the alternating magnetic field A1 of the frequency F1. At the same step, the probe current generator 1 is tuned to the frequency F2, the robot 6 again starts scanning 180 degrees, the sensor coils located on the sliding manipulators 3a fix the amplitude of the A2 field at the frequency F2. Data on the amplitude of signals at frequencies F1 and F2 are attached to the longitudinal and angular coordinates, allowing you to determine the position of the defect. The presence or absence of a defect is determined by the fact that the received signals A1, A ₂ exceed a certain predetermined threshold A _th .

- while the residual thickness of the metal H in the zone of the defect is determined by mathematical processing of signals at each point of the monitored object and is uniquely determined as a function of two variables H (A1, A2).

FIG. 2 shows the implementation of the achievement of the technical result in the form of a graph of the amplitude distribution of the two-frequency signal in the defective zones. The graph was obtained by cutting one vertical line (one rotation of the rotation, section A-A of Fig. 1).

On the graph (Fig. 1) can be divided into three zones. In two zones (zone 2 and zone 3) an excess of the signal amplitude of 300 Hz is observed above the signal amplitude with a frequency of 600 Hz, which is a sign of a surface defect with a depth of less than 50% of the wall thickness. In zone 1, a signal with a frequency of 600 Hz is observed above the signal with a frequency of 300 Hz, which is a sign of a through defect.

The claimed technical solution, namely the method and device for the method of magnetic control, provides an algorithm for data processing aimed at obtaining reliable information, excluding information on structural elements, such as a weld, surfacing, a patch on which a "false positive" of the system occurs.

Claims (3)

1. A method for a magnetic control method that includes a circular scan process by a diagnostic robot that moves inside a pipeline along a monitored pipeline section with the possibility of performing a full rotation by the rotation unit, characterized in that the diagnostic robot moves in steps where the length of each step is equal to the width of the grip an alternating magnetic field sensor, while at the time of rotation of the rotary assembly, the amplitude of the alternating magnetic field is fixed at least d For two different frequencies at each point of the test surface with the possibility of estimating the depth of the defect and determining its position by binding the amplitudes of the signals to the longitudinal and angular coordinates. 2. The device for the magnetic control method according to claim 1, which includes a magnetic control module placed on the rotary node of the diagnostic robot, characterized in that the module is equipped with at least one sliding manipulator with an alternating magnetic field sensor placed on it less than one coil inductance, while the drive of each of the manipulators is controlled by signals from the gap meter, located in the variable field sensor. 3. The device according to claim 2, characterized in that the remote-controlled diagnostic robot is equipped with a tracked mover.

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