RU2510500C1 - Method and device for diagnostics of buried pipeline - Google Patents

Abstract

FIELD: instrumentation.

SUBSTANCE: proposed device consists in measurement of gradients of permanent magnetic field components actual in time at several levels with the help of at least three strips of magnetic resistors displaced by operator along pipeline axis. Two strips of magnetic resistors are arranged vertically and one strip is fitted horizontally. Every strip is composed of three three-component transducers. Gradients (∂Xi/∂y, ∂Yi/∂y, ∂Zi/∂y) are computed proceeding from recorded data for every component of the transducer for time interval defined by hardware performances, that is, at the rate of 6256 measurements a second. Said gradients are defined as the difference (Xi+1-Xi)/Δy, (Yi+1-Yi)/ Δy, (Zi+1-Zi)/ Δy at Δy→0. Application of gradients obtained in small time interval allows getting rid of errors related with unstable operation of transducers, change in their sensitivity, increase in scatter of transducer parameters and their dependence upon temperature.

EFFECT: fast response, accurate detection of buried pipeline defects, better operating performances.

4 cl, 2 dwg

Description

The proposed technical solution relates to the field of flaw detection of the state of the pipeline and can be used to detect and outline zones of stress-strain state of the metal of the pipeline, violate the integrity of the pipeline and its insulation coating, identify unauthorized taps, as well as diagnose the technical condition of other underground metal pipelines and metal structures.

The use of magnetoresistive sensors for flaw detection of underground metal pipelines is one of the most promising areas of remote non-destructive testing. This is due to a number of their advantages, in particular their small size and weight, low power consumption, high speed and high sensitivity.

Currently used for diagnostic purposes, flux-gate sensors are characterized by a number of disadvantages, such as the effect of high-frequency harmonics in the excitation circuit, the effect of the own inductance of the field windings, high noise level, significant dimensions, weight, and energy consumption.

The most well-known magnetoresistive sensors of Honeywell (Website of Honeywell, http://www.honeywell.ru), for example a biaxial sensor NMS 1022 or a triaxial sensor NMS 1055. The magnetoresistive anisotropy effect, which consists in the permalloy ability (NiFe), is the basis of the principle of operation of magnetoresistive sensors. ) the films change their electrical resistance depending on the mutual orientation of the current flowing through it and the direction of its magnetization vector. At an angle between these directions of 90 ° it is minimal, at an angle of 0 ° - maximum.

To build the sensor, four magnetoresistive films are connected in a bridge circuit and form the shoulders of the bridge. To increase the sensitivity, each shoulder of the bridge consists of several magnetoresistive films installed in parallel.

Surrounded by a magnetoresistive bridge, two flat coils SET / RESET and OFFSET are installed. The supply of a short installation pulse of 2 ... 5 A with a duration of 1-2 μs through the SET / RESET coil creates a magnetic field orienting the magnetic domains of all the films in the direction of the easy axis corresponding to the maximum sensitivity. At the same time, the influence of hysteresis on the measurement results is eliminated. This procedure will be performed before each measurement of the field and therefore is a significant methodological inconvenience in continuous measurements.

To compensate for the external parasitic magnetic field created by any ferromagnetic objects, a direct current of 20 ... 50 mA is passed through the OFFSET coil. The external field and the field of the OFFSET coil are added up taking into account their sign.

A number of technical solutions are known for diagnosing the technical condition of an underground pipeline using magnetoresistive sensors.

For example, a device is known for detecting local defects of conductive objects according to the patent of the Russian Federation No. 2308026, priority date 04/20/2005. In this device, to create a three-dimensional image of defects, a dipole type magnetic field source matrix, an electronic scanning unit and a set (9 pieces) of highly sensitive one-component sensors are used, which are magnetoresistive sensors with high ultimate sensitivity. A disadvantage of the known technical solution is the need for a significant approximation of the device to the pipe and the need to use a matrix of sources of constant magnetic field.

A device is also known for non-contact detection of the presence and location of defects in a metal pipeline according to the patent of the Russian Federation for utility model No. 86015. To solve this problem, the device includes a system of magnetoresistive magnetic field sensors, an ADC (analog-to-digital converter), a frequency generation and division unit, a control unit, a binding unit, a memory unit, and an accelerometer unit.

The disadvantage of this device is the fact that when exposed to a strong external magnetic field, the sign of the bridge circuit may change, which worsens the sensitivity of the sensors, increases the spread of the parameters of the sensors and their dependence on temperature. The method of using magnetoresistive sensors (conventional subtraction) due to the spread of the parameters of the sensors virtually eliminates the possibility of obtaining gradients of the field components necessary to solve the stated problem of remotely detecting the presence and location of defects in a metal pipeline.

The closest in terms of essential features to the proposed technical solution are the PDMG digital pedestrian two-coordinate magnetometer-gradient meter with magnetoresistive sensors and the method for detecting defects in underground pipelines based on this device, described on the website http://imlab.narod.ru/Eleckron/MagnGrad/ Def_1022.htm

The prototype consists of two identical two-coordinate magnetometers built on the basis of mutually orthogonal biaxial magnetoresistive transducers NMS1022 manufactured by Honeywell. The magnetometers are located at some distance from each other (measuring base 1 meter) at the ends of a non-magnetic rod (aluminum profile of an L-shaped section) so that the magnetoresistive transducers are in the same plane and their measuring axes are parallel and equally oriented. By turning the rod, a different orientation of the plane of the transducers relative to the surface of the Earth is set. Magnetometers are connected to the power supply, control and subtractors. A digital voltmeter is used to indicate the readings. The power supply, control and subtractor unit and voltmeter are located in the middle of the rod. The battery is attached from below to the rod. As a magnetic field sensor, a two-coordinate magnetoresistive converter on a TD1 chip NMS1022 from Honeywell was used. This sensor requires reset / set signals (current pulses with an amplitude of up to 0.5 A and a duration of about 1 μs).

The disadvantages of the prototype.

1. Due to the need to use reset / set signals manually, the device is not suitable for continuous measurements in motion.

2. A significant drawback of the device is the ability to measure along one axis, while the methodological need for measurements along the other axis will require repeated passage of the pipeline, at least in abnormal areas.

3. Indication of readings is carried out using a digital voltmeter; therefore, sufficient speed cannot be ensured. This procedure will be performed before each measurement of the field and therefore is a significant methodological inconvenience in continuous measurements.

The objectives of the invention are the creation of such a method and device for diagnosing the technical condition of an underground pipeline, which would allow the most efficient use of the main advantages of magnetoresistive sensors (small size, weight, energy consumption, speed) and minimize difficulties when using them as magnetometers or magnetometers-gradiometers (absence absolute measurements, the need for magnetization reversal, difficulties in measuring field gradients, displacement of the operating point, scatter expandable and parameters).

In the proposed device due to the greater, in comparison with flux-gate sensors, speed, greater accuracy and detail in solving flaw detection tasks are achieved. The operational characteristics of the measuring complex are improved by reducing weight, dimensions and energy intensity.

Thus, the technical result of the invention is to increase the speed and accuracy of identifying defects in underground pipelines, as well as improving the operational characteristics of the device for diagnosing the technical condition of underground pipelines.

The technical result is achieved due to the fact that in the method for diagnosing the technical condition of an underground pipeline, including measuring the induction of a constant magnetic field over the pipeline when moving the line of magnetoresistive field sensors along the axis of the pipeline, mathematical processing of the measurement and, based on the data obtained, identification and ranking of the features of the technical condition of the pipelines, it is proposed :

- the measurement of the gradients of the induction of a constant magnetic field to produce continuously, at least eight points in the annular space when moving at least three lines of sensors,

- moreover, two lines of sensors are proposed to be arranged vertically, and one horizontally relative to the surface of the Earth,

- each sensor line is proposed to be composed of three three-component sensors,

- carry out the mathematical processing of measurements by solving the redundant system of equations compiled for the gradients of induction of a constant magnetic field, and determine the spatial path of the pipeline based on the dependence of the magnitudes of the gradients on the immersion depth of the pipeline (N) and on the distance between the sensor line and the projection of the pipeline axis (m), while the identification of defects and their ranking should be based on the calculated geometric parameters and components of the magnetic moments of the defects, namely Mdx, Mdu, Mdz, and radientov moments along the axis (y), i.e., ∂Mdh / ∂y, ∂Mdu / ∂y and ∂Mdz / ∂y.

The technical result is also achieved due to the fact that the device for diagnosing the technical condition of an underground pipeline, including a line of magnetoresistive sensors of a constant magnetic field, a field computer and a data acquisition and control unit (BSDU), is proposed to be performed as follows:

- at least three lines of sensors,

- moreover, two rulers are proposed to be placed vertically, and one horizontally relative to the surface of the Earth,

- each sensor line is proposed to be made of three three-component sensors, the outputs of which are connected to the inputs of the corresponding operational amplifiers of each component, while the outputs of the operational amplifiers are connected to the inputs of the corresponding overload signaling devices and a magnetization reversal generator, and the outputs of the overload signaling devices are connected to the inputs of the corresponding analog-to-digital converters ( ADC), the outputs of which are connected to the data acquisition and control unit (BSDU).

An additional feature of the device is that the BSDU includes at least eight relay modules, the inputs of which are connected to the outputs of the corresponding analog-to-digital converters (ADC), while the outputs of the relay modules through the interaction channels are connected to the inputs of the corresponding receiving modules, the outputs of which are connected with a shaper of output signals, which in turn is connected via a USB port to a personal computer.

The essence of the proposed technical solution is illustrated by the following figures.

Figure 1 shows a block diagram of a device for diagnosing the technical condition of underground pipelines, where

1-8 - magnetoresistive sensors

9-32 - differential operational amplifiers

33-86 - operating mode exit signaling devices

87 - magnetization reversal current generator

88-95 - multi-input analog-to-digital converters

96 - data acquisition and control unit

97 - field computer.

Figure 2 shows an example block diagram of the BSDU, where

98-105 - relay modules made on LVDS chips,

106-113 - channels of interaction between receiving and relaying modules based on the SPI interface,

114-121 - receiving modules made on LVDS chips,

122 - output driver, made on the basis of FPGA (programmable logic integrated circuit),

123 - USB port for connecting to a personal computer.

The essence of the invention is to realize the possibility of measuring real-time gradients along the longitudinal axis of the pipeline and then calculating the components of the constant magnetic field at several levels using at least 3 lines of magnetoresistors moved by the operator when moving along the axis of the pipeline. Two lines of magnetoresistors are installed vertically, and one horizontally. Each line consists of three three-component sensors. Gradients are measured (i.e., ∂Xi / ∂у, ∂Yi / ∂у, ∂Zi / ∂у) for each component of each sensor over a time interval determined by the speed of the equipment, i.e. at a speed of 6256 measurements per second. Gradients are defined as the differences (Xi + 1-Xi) / Δy, (Yi + 1-Yi) / Δy, (Zi + 1-Zi) / Δy as Δy → 0. The use of gradients obtained over a short time interval allows us to get rid of errors associated with the instability of the sensors, changes in their sensitivity, an increase in the dispersion of the parameters of the sensors and their dependence on temperature.

Due to the high speed of the sensors, their resolution increases. The values of the gradients are entered into the memory of the field computer and then transferred to the desktop computer.

In a desktop computer for each line of all three lines of magnetoresistors, i.e. for 21 components, operator speeds are calculated. Calculations are performed programmatically using the reaction of virtual filters. Filters are designed for the operator moving speed within 0.5-2.5 m / s with a resolution of 0.1 m / s. The obtained velocity values are averaged. Based on the average speed of the operator moving, time gradients are converted to distance gradients as a product of speed and time. Based on the obtained gradients, relative gradients and magnetic moments are calculated at various points in the annular space.

Indeed, the gradients (Xi + 1-Xi) / Δy, (Yi + 1-Yi) / Δy, (Zi + 1-Zi) / Δy as Δy → 0 are functions of the magnetic moments of defects Md along the axes X, Y, Z, the depth of the pipeline N and the operator’s departure from the projection of the pipe axis onto the day surface (m (i.e., by the functions F1 (Md, H, m))). Relative gradients i.e. the functions F2 (H, m), which are functions of the relations (Xi + 1-Xi) / (Yi + 1-Yi), (Yi + 1-Yi) / (Zi + 1-Zi) and (Xi + 1-Xi) / (Zi + 1-Zi), do not depend on magnetic moments and depend only on the depth of immersion of the pipeline (N) and the departure of the operator from the projection of the axis of the pipe onto the surface (m).

Using an excess system of equations formed due to the high speed of the system and the presence of a line of sensors, we obtain an excess system of equations. Having solved this system, for example, by the least squares method, we obtain the dependences H (y) and m (y). Based on these data, we obtain the spatial trajectory of the pipeline. Using the values of H (y) and m (y) at various points of the annulus and the gradients (Xi + 1-Xi) / Δу, (Yi + 1-Yi) / Δу, (Zi + 1-Zi) / Δу as Δу → 0, the components of the magnetic moments and the gradients of the magnetic moments along the axis (y) are calculated.

A block diagram of a device for diagnosing the technical condition of a pipeline based on magnetoresistive sensors (Fig. 1) consists of a block of magnetoresistive triaxial sensors 1-8 of the NMS 1055 type, combined into a design that allows characterizing the magnetic field in a limited volume of the annular space, and assembled from 8- mi boards. To build the sensor, four magnetoresistive films are connected in a bridge circuit and form the shoulders of the bridge. Surrounded by a magnetoresistive bridge, two flat coils SET / RESET and OFFSET are installed.

To increase the sensitivity, each shoulder of the bridge consists of several magnetoresistive films installed in parallel. In addition, on each of the boards there is a block of differential amplifiers 9-32, a block of signaling devices 33-80, a current generator 87. The output of each of the bridges of the magnetoresistor is connected to differential amplifiers 9-32, signaling devices for exiting the operating mode 33-86 (level indication circuits signal), current generator 87, ADC 88-95. The outputs of the ADC 88-95 are connected to the BSUU unit (data acquisition and control unit) 96. The BSUU 96 unit via the USB port (serial data transmission interface) is connected to the field computer 97.

The principle of operation of the Honeywell NMS 1055 triaxial magnetoresistive sensors (Honeywell website, http://www.honeywell.ru) is based on the magnetoresistive anisotropy effect, which consists in the ability of a permalloy (NiFe) film to change its electrical resistance depending on the relative orientation of the flowing through of the current and the direction of its magnetization vector. At an angle between these directions of 90 ° it is minimal, at an angle of 0 ° - maximum.

To compensate for the external parasitic magnetic field created by any ferromagnetic objects, a direct current of 20 ... 50 mA is passed through the OFFSET coil. The external field and the field of the OFFSET coil are added up taking into account their sign.

The supply of a short installation pulse of 2-5 A with a duration of 1-2 μs through the SET / RESET coil creates a magnetic field orienting the magnetic domains of all the films in the direction of the easy axis, corresponding to the maximum sensitivity. At the same time, the influence of hysteresis on the measurement results is eliminated.

From the output of the bridge circuit of triaxial magnetoresistive sensors 1-8, output signals (proportional to the difference between the components of the magnetic field induction along the respective axes) are fed to the differential inputs of amplifiers 9-32 (for example, АМР04 from Analog, AMP04 from Analog Devices) and then through the signaling devices mode 33-86 to the inputs of multi-channel ADC 88-95.

If one of the signals from the output of the differential amplifier exceeds the set threshold in amplitude, the current generator 87 is turned on. The current generator performs magnetization reversal of the sensor by applying a bipolar pulse with an amplitude exceeding the zone of linear signal conversion. After an impulse is supplied, the sensors are remagnetized, enter the operating mode and continue to work.

In analog-to-digital converters 88-95, analog signals are digitized and transmitted to the BSDU 96. The BSDU 96 collects data and transfers them into formats suitable for transmission via the USB port to the field computer 97. An example of the implementation of block 97 is shown in FIG. 2.

During processing, all accumulated data in the field computer is dumped to the high-speed desktop computer. In a desktop computer, using the reaction of virtual filters, the speed of the operator is calculated. According to the data obtained for the gradients (Xi + 1-Xi) / Δy, (Yi + 1-Yi) / Δy, (Zi + 1-Zi) / Δy as Δy → 0, we obtain an excess system of equations. Having solved this system, for example, by the least-squares method, we obtain the dependences of the pipeline immersion depth H (y) and the operator’s distance from the projection of the pipeline axis m (y) onto the day surface. Based on these data, we obtain the spatial trajectory of the pipeline.

Using the values of H (y) and m (y) at various points of the annulus and the gradients (Xi + 1-Xi) / Δу, (Yi + 1-Yi) / Δу, (Zi + 1-Zi) / Δу as Δу → 0, the components of the magnetic moments (Mdx, Mdu, Mdz) and the gradients of these moments along the axis (y) are calculated, i.e. ∂Mdh / ∂y, ∂Mdu / ∂y and ∂Mdz / ∂y. Based on these data, defects in pipelines are identified, their ranking and refinement of pipeline geometries.

If it is necessary to refine the obtained data, the integration of gradients (Xi + 1-Xi) / Δy, (Yi + 1-Yi) / Δy, (Zi + 1-Zi) / Δy with the subsequent receipt of Xi, Yi, Zi at least 8 points of space. To increase the accuracy, the values of Xi, Yi, Zi are averaged.

Thus, after integrating the gradients, we have a set of components Xi, Yi, Zi at least at 8 points in space. In fact, given the speed of the equipment, their number is much larger. According to the data obtained, the module of the field components T ₁ , T ₂ and T _{3 is} calculated. Based on these data, refined pipeline geometrization, determination of magnetic moments and solving flaw detection problems are carried out.

The problem of geometrization is most easily solved with vertical magnetization of the pipeline, i.e. at an angle of inclination of the Earth's magnetic field of 90 °.

, $$\left|T_2\right|$$

, $$\left|T_3\right|$$

определяются из соотношенийIn this case, the design of the proposed device allows to obtain components of a constant magnetic field at three points located along the vertical axis. Then the field moduli $$|\; |\; |T_{\mathrm{one}}|\; |\; |$$

, $$|\; |\; |{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2|\; |\; |$$

, $$|\; |\; |{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_3|\; |\; |$$

are determined from the relations

$$|\; |\; |T_{\mathrm{one}}|\; |\; |=\frac{2|\; |\; |M|\; |\; |}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2};|\; |\; |{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2|\; |\; |=\frac{2|\; |\; |M|\; |\; |}{{\left(h+l\right)}^2+x^2};|\; |\; |{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_3|\; |\; |=\frac{2|\; |\; |M|\; |\; |}{{\left(h+2l\right)}^2+x^2}\text{,}\left(\text{one}\right)$$

- модуль магнитного момента, $$|\; |\; |M|\; |\; |$$

- module of the magnetic moment,

l is the distance between the magnetic field sensors,

h is the distance between the lower sensor and the center of the pipeline,

x is the coordinate of the magnetic field sensors along the x axis.

Then the relations of the modules are equal

$$\frac{|\; |\; |T_{\mathrm{one}}|\; |\; |}{|\; |\; |{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_3|\; |\; |}=\frac{{\left(h+2l\right)}^2+x^2}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2}=A,\left(\text{2}\right)$$

$$\frac{|\; |\; |T_{\mathrm{one}}|\; |\; |}{|\; |\; |{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2|\; |\; |}=\frac{{\left(h+l\right)}^2+x^2}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2}=B.\left(\text{3}\right)$$

After the transformations, we have

$$A{(h+l)}^2+A{x}^2=B{(h+2l)}^2+B{x}^2\text{,}\left(\text{four}\right)$$

where from $$x=\sqrt{\frac{B{(h+2l)}^2-A{(h+l)}^2}{A-B}}.\left(\text{5}\right)$$

To obtain an explicit expression for h, using (1) and (2), we have

$$h=\frac{\mathrm{one}}{2}\cdot \frac{\left(A+3-\mathrm{four}B\right)}{\left(2B-A-\mathrm{one}\right)}.\left(\text{6}\right)$$

Thus, the vertical magnetization of the pipeline solves the problem of its geometrization by using measurements of the components of the pipe field, at least at three points located along the vertical axis. The field modulus is determined from the measurements of the field components. Vertical or close to vertical magnetization takes place for a substantial part of the territory of the Russian Federation. Based on relations (1), the magnetic moment of the pipeline is easily determined, and its anomalies along the longitudinal axis characterize the defects of the pipeline.

In the case of oblique magnetization Z _k and H _{k, the} components are determined from the relations given by V. M. Yanovsky (Earth magnetism, M., 1953, p. 346):

$$Z_k=2|\; |\; |M|\; |\; |\cdot \frac{({\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2)\cos \phi -2hx\sin \phi }{{({\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2)}^2}\text{,}\left(\text{7}\right)$$

, $$H_k=2|\; |\; |M|\; |\; |\cdot \frac{(h^2-x^2)\sin \varphi -2hx\cos \varphi }{{({\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2)}^2}$$

,

Where

Z _k and H _k are the field components during oblique magnetization,

φ = 90 ° -J,

where J is the angle of magnetization.

With vertical magnetization

, $$Z_B=\frac{2\left|M\right|\cdot (h^2-x^2)}{{(h^2+x^2)}^2}$$

, $$H_B=\frac{\mathrm{four}|\; |\; |M|\; |\; |\cdot hx}{{({\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2)}^2}$$

, $$Z_B=\frac{2|\; |\; |M|\; |\; |\cdot (h^2-x^2)}{{({\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2)}^2}$$

,

Where

Z _B and H _B are the components of the field during vertical magnetization.

The magnetization angle can be measured, for example, by a flux gate or approximately determined from magnetic inclination maps.

It is easy to show that

$$\sqrt{{\mathrm{<figure-callout\; id="2"\; label="Z\; k"\; filenames="00000025.png"\; state="\{\{state\}\}">Z\; </figure-callout>}}_k^{}+{\mathrm{<figure-callout\; id="2"\; label="H\; k"\; filenames="00000025.png"\; state="\{\{state\}\}">H\; </figure-callout>}}_k^{}}=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="Z\; B"\; filenames="00000025.png"\; state="\{\{state\}\}">Z\; </figure-callout>}}_B^{}+{\mathrm{<figure-callout\; id="2"\; label="H\; B"\; filenames="00000025.png"\; state="\{\{state\}\}">H\; </figure-callout>}}_B^{}},\text{where from}|\; |\; |\text{Tk}|\; |\; |=|\; |\; |\text{Tv}|\; |\; |.\left(\text{9}\right)$$

You can also refine the value of h in other ways:

- measure the area of the positive part of the curve Z _k over the x-axis (Q);

- measure the value of Z _kmax , i.e. the maximum value of Z _k (Z _kmax );

- determine the immersion depth h from the ratio

-

$$h=\frac{Q}{Z_{k\max }}\text{.}\left(\text{10}\right)$$

. В этом случае модули поля определяются из соотношенийWhen using the horizontal axis of the proposed installation can also be determined by the parameters x, h and $$|\; |\; |M|\; |\; |$$

. In this case, the field moduli are determined from the relations

, $$|\; |\; |T_{\mathrm{four}}|\; |\; |=\frac{2|\; |\; |M|\; |\; |}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2}$$

,

, $$|\; |\; |{\mathrm{<figure-callout\; id="5"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_5|\; |\; |=\frac{2|\; |\; |M|\; |\; |}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+{(x+m)}^2}$$

,

, $$|\; |\; |{\mathrm{<figure-callout\; id="6"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_6|\; |\; |=\frac{2|\; |\; |M|\; |\; |}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+{(x+2m)}^2}$$

,

, $$\frac{|\; |\; |T_{\mathrm{four}}|\; |\; |}{|\; |\; |{\mathrm{<figure-callout\; id="6"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_6|\; |\; |}=\frac{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+{(x+2m)}^2}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2}=c$$

,

. $$\frac{|\; |\; |T_{\mathrm{four}}|\; |\; |}{|\; |\; |{\mathrm{<figure-callout\; id="5"\; label="T"\; filenames="00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_5|\; |\; |}=\frac{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+{(x+m)}^2}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="00000025.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+x^2}=d$$

.

Where easy to get

, $$X=\frac{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="00000025.png"\; state="\{\{state\}\}">m</figure-callout>}}{2}\cdot \frac{[c-(\mathrm{four}d-3)]}{[2d-c-\mathrm{one}]}$$

,

, $$h=\sqrt{\frac{d{\left(x+2m\right)}^2-c(x+m)}{c-d}}$$

,

where m is the distance between the sensors along the horizontal axis.

Based on the data obtained, geometrization can be carried out and the magnetic moment of the defect itself can be determined.

The refinement of the obtained data on the determination of the magnetic moment of a defect is carried out if it is possible to calculate or measure the components of the anomalous magnetic field Za and Ha at least at two levels (upper - “top” and lower - “lower”), and compare the defect horizontal or vertical dipole. In this case, subject to the vertical magnetization of the defect, we obtain a system of 2 square equations with two unknowns: h and x.

The first quadratic equation for the vertical sensor (vertical tube) of the lower magnetoresistor has the form

(Za / Na) lower = A = - (2h ^2- x ² ) / 3hx,

where h is the distance from the center of the dipole to the projection of the center of the lower magnetoresistive sensor on the Z axis,

x is the distance along the horizontal axis from the center of the dipole to the projection of the vertical sensor (vertical tube) on the X axis.

The second quadratic equation for the vertical sensor (vertical tube) of the upper magnetoresistor has the form

(Za / Ha) top = B = - (2 (h + 2L ₁ ) ^2- x ² ) / 3 (h + 2L1) x,

where 2L ₁ is the distance between the upper and lower magnetoresistive sensors.

Having solved the first quadratic equation with respect to (h / x) = m, we have

h / x = m = (- 3A +/- √9A ² +8) / 4.

Having solved the second quadratic equation with respect to (h + 2L ₁ ) / x = n, we have

(h + 2L) / x = n = (- 3V +/- √ 9V ² +8) / 4.

Thus, we have

h = 2mL ₁ / mn,

x = 2 / n-m.

The immersion depth of the center of the dipole from the Earth's surface (H) is determined from the relation

H = h-Hz,

where Нз is the height of the lower magnetoresistor above the Earth's surface or, in other words, the distance between the center of the lower magnetoresistor and the X axis, determined by the design features of the proposal and the growth of the operator (usually in the range of 0.5-0.7 meters).

Similarly, the defect is geometrized if it is possible to calculate or measure the components of the anomalous magnetic field Za and At at least two points located at the same level, for example, at the level (z + L ₁ ) = p, and remote from the Z axis at different distances. The left magnetoresistor is removed from the Z axis by the distance X “lion” and the right magnetoresistor is removed by the distance X “right”.

Denote Chlev = q, Khrav = q + 2k, where 2k is the distance between the left and right magnetoresistors. Then, after simple simplifications, we have the quadratic equation

(Zal / Left) lion = E = - (2p ² -q ² ) / 3pq,

Having solved the equation with respect to (p / q), we have

(p / q) = c = - (3E +/- √ 9E ² +8) / 4.

Similarly, we have the equation for the right sensor

(Z right / Direction) right = F = - (2p ² - (q + 2k) ² ) / 3p (q + 2k).

Having solved the equation with respect to (p / q + 2k), we have

(p / q + 2k) = d = - (3F +/- √9F ² +8) / 4.

Further, using the expressions for (p / q) and (p / q + 2k), we have

q = 2dk / (c-d),

p = 2dck / (c-d).

The defect geometrization method used can also be used to determine the position of thin (diameter 114 mm or less) oilfield pipes.

Technical and economic effect:

- low cost of magnetoresistors (5 thousand rubles a piece),

- the possibility of their easy purchase (website of Honeywell, http://www.honeywell.ru),

- high maintainability,

- small dimensions, weight and energy intensity,

- no need for time-consuming configuration.

Claims (4)

1. A method for diagnosing the technical condition of an underground pipeline, including measuring the induction of a constant magnetic field above the pipeline when moving the line of magnetoresistive field sensors along the axis of the pipeline, mathematical processing of the measurement and, according to the data obtained, identifying and ranking features of the technical condition of the pipelines, characterized in that the measurement of the gradients of the induction of constant the magnetic field is produced continuously at least eight points in the annular space at n Moving at least three lines of sensors, with two lines vertically and one horizontal to the Earth’s surface, each line of sensors consists of three three-component sensors, the mathematical processing of the measurements is carried out by solving an excess system of equations compiled for the gradients of induction of a constant magnetic field, and the spatial path of the pipeline is determined on the basis of the dependence of the magnitude of the gradients on the depth of the pipeline (H) and on the distance between the ruler yes sensors and the projection of the pipeline axis (m), while the identification of defects and their ranking are based on the calculated geometric parameters and components of the magnetic moments of the defects, namely, Mdx, Mdy, Mdz, and moment gradients along the axis (y), i.e. ∂Мдх / ∂y, ∂Мдy / ∂y and ∂Мдz / ∂y. 2. A method for diagnosing the technical condition of an underground pipeline according to claim 1, characterized in that the movement speeds of the sensors are calculated based on the response of the virtual filters during processing on a desktop computer. 3. A device for diagnosing the technical condition of an underground pipeline, including a line of magnetoresistive sensors of a constant magnetic field, a field computer and a data acquisition and control unit (BSDU), characterized in that it includes at least three sensor lines, with two lines vertically and one horizontally relative to the Earth’s surface, each sensor line consists of three three-component sensors, the outputs of which are connected to the inputs of the respective operational amplifiers of each component, while the outputs of operational amplifiers are connected to the inputs of the corresponding overload signaling devices and the magnetization reversal generator, and the outputs of the overload signaling devices are connected to the inputs of the corresponding analog-to-digital converters (ADCs), the outputs of which are connected to the data acquisition and control unit (BSDU). 4. The device according to claim 3, characterized in that the BSDU includes at least eight relay modules, the inputs of which are connected to the outputs of the corresponding ADCs, while the outputs of the relay modules through the interaction channels are connected to the inputs of the corresponding receiving modules, the outputs of which are connected to driver output signals connected via USB-port with a personal computer.

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