Method for non-contact detection of position and type of defects of metallic structures and device for realization of said method

FIELD: pipeline construction technologies.

SUBSTANCE: method shows presence and location of defects of metallic pipelines, includes measuring above pipeline in given points during movement of magnetic field vectors in rectangular coordinates, by at least two three-component sensors, tensor of magnetic field gradients is built, by matrix transformation received information is processed, on basis of results background value is estimated and deviations from this value, on basis of difference of which for given criterion value from background value presence and location of defects of metallic pipelines is decided and magnetic graph is built to show location of defects. Device for realization of method has registration sensors system, quartz generator, frequency divider, analog-digital converter, control block, threshold block, sound and light indication block, automatic battery charge indicator, block for calculation of magnetic field gradients, block for showing information, recording device segment, recording control block, situation alignment block, block for satellite absolute geographic alignment GPS, block for selecting recording segment.

EFFECT: broader functional capabilities, higher trustworthiness, higher efficiency.

2 cl, 4 dwg

 

The invention relates to pipeline transport, oil and gas industry, utilities, non-destructive testing of structures, corrosion protection, environmental protection and can be used in other industries, operating pipelines (construction, energy, nuclear, etc.)

Known contact method of detection of local defects of the pipeline by registering anomalies of the magnetic field is pre-magnetized pipe special devices - in-line shells flaw detector (RF Patent No. 2102652, CL 6 F 17 D 5/00, publg.). The method includes equipment highway cameras start receiving treatment devices and shell-detector, washing, cleaning the internal surface of pipelines and ensuring full bore section (for the purpose of preparing the track to pass shell-detector), pass shell-detector with simultaneous magnetization of the pipe wall, registration anomalies of the magnetic field by magnetic fields of the dispersion and saturation, writing information in the memory, decoding the received information to conclude about the location and nature of the detected defects.

According to this method is used to determine the location parameters and the presumable cause of all local defects t is unaproved.

The possibilities of pigs allows to identify the following types of defects: 1 - geometric anomalies - dents, buckles, ovality cross-section; 2 - metal loss mechanical, corrosion or technological origin, as well as defects such as delaminations, inclusions; 3 - detection of longitudinally-oriented SCC cracks and crack-like defects (incomplete penetration, incomplete fusion, slag inclusions), including welded joints.

The use of pigs characterized by high cost, labor intensive, limited in mass implementation due to the unreadiness of pipelines (neobrazovannost cameras start reception of a shell-detector, as reduced cross-section due to the so-called welding "grata", the lack of pipeline cleaning, too big differences in depth, steep slopes, rises the road). For implementing the method requires considerable preparatory work: in particular, for magnetic shells - pre-magnetization of the pipeline up to very high levels of residual magnetization (in the field of magnetic field saturation). This creates a further technical problem of demagnetization of the pipeline before renovations after crossing the magnetic shell.

There is a method of determining the voltage is but-strain state of a product of a ferromagnetic material (RF Patent No. 2155943, CL G 01 L 1/12, 2000). The method includes measuring the normal component of the magnetic field strength HP along the surface of the product at various points, the definition of the gradient magnetic-eld strength of HP between the ends of the fixed length lbthe section of the line, then measure the component of the HP simultaneously at two points at the ends of the fixed length segment of Ib, complanare removed from the surface at a distance of Itofrom the initial cut, continue to measure the HP of the normal component at two points at equal distances Itofrom each previous segment measurements, observing complanarity segments of the measurement, when the measurement points change the sign of the component of the HP determine gradients |HP|/ Iband HP/ Itovalues of the normal component of the magnetic field at a fixed length segments of Iband Itocompare the above gradients and the maximum value of one of these gradients determine the zone of maximum deformation.

For implementing the method requires the measurement of the normal component that requires access to the test surface, in particular, involves the preliminary autopsy (pitting) of the pipeline.

Closest to the proposed the th method according to essential features and the achieved effect is a contactless method for predicting leaks in pipelines (RF Patent 2062394, CL F 17 D 5/02, 1996), including the measurement above the pipe projection of the magnetic field vector H in the process of moving the sensor along the axis of the pipeline on the surface of the Earth in space rectangular coordinates.

The characteristic parameters select the gradient α-the horizontal component of the tension of the self-magnetic field line, oriented along its axis, and the ratio of β vertical and horizontal components of the magnetic field. Measure modules characteristic parameters, compare the change in the boundary of the discrete areas and on the maximum value of the modulus of the gradient determine the predicted location of the defect in the pipeline, but the components of the tension of the self-magnetic field line identify the type and size of the defect.

This method is not sensitive enough when registering magnetic anomalies on pipelines with minor mechanical stresses and, consequently, low levels of stress-strain state, it is not possible to automatically generate a conclusion about the location of defects in the metal for certification of equipment (pipelines).

A device of non-contact magnetometric control the state of the pipeline metal [Certificate is a useful model of the Russian Federation No. 11608, CL G 01 N 27/72, 1999], which contains the registration sensors connected to the analog-to-digital Converter connected to the memory unit, the control unit is connected via the node management account, and the address of the node memory unit, crystal oscillator, coupled to the frequency divider, the threshold unit connected to block light and sound alarm, automatic discharge indicator battery.

The disadvantage of this device are insufficient sensitivity, does not allow to record the defects of pipes of small diameters with great depth, as well as defects that cause minor deviations of the level of stress-strain state from the background values.

The present invention is to develop a method for the contactless detection of the location, nature and severity of defects in metal structures that do not have these disadvantages, and an apparatus for implementing this method.

The technical result consists in expanding the scope and improving the accuracy of the information about the location of magnetic anomalies and caused their metal defects on objects with negligible background levels of the stress-strain state of pipelines of small diameter, with great depth, with low levels of operating pressure is placed and mechanical stresses) at the expense of increasing the sensitivity of reception of magnetic anomalies, special selection step of recording information, as well as the number and aperture sensors recording, accounting for the depth of the pipeline or the shortest distance to the surface of the inspected metal.

The result is achieved that the method of non-contact detecting the presence and location of defects in the metal pipeline, including the measurement above the pipeline induction magnetic field at specified points in the process of moving conducting measurements of magnetic field vectors in rectangular coordinates, at least two three-component sensors are tensor magnetic field gradients by matrix transformation spend processing the received information, the results of processing to determine a background value and deviations from this value, the difference of which on a given criterion value from the background value judgments about the presence and location of defects in metal pipes and build the magnetogram indicating the location of defects, and the fact that the device for contactless detection of the presence and location of defects in the metal piping that contains a system of registration sensors connected to analog-to-digital Converter, a crystal oscillator, connected through a frequency divider with analog-to-digital Converter unit in the management, the block threshold level, coupled with block sound and light indication, automatic discharge indicator battery further comprises a display unit information, the computing unit of magnetic field gradients, block situational binding and block absolute geo-referencing, the segment of the storage device, the block select record segment and the control unit of account, while the control unit is connected to the unit case bindings, block absolute geo-referencing, the block select record segment and the control unit account connected with the computing unit of magnetic field gradients, the block select record segment is connected to the segment of the storage device connected via the computing unit of magnetic field gradients unit information display, connected to the block threshold level and an automatic indicator, battery low, analog-to-digital Converter connected to the computing unit of magnetic field gradients.

Furthermore, the method and device allow for:

accounting situational bindings (location of aboveground structures, intersections of routes) in absolute geographic coordinates to further speed up and facilitate the selection of the points of opening of the pipeline in areas of identified defects;

processing, interpretation and visualization the July survey results in the form of graphs-magnetograms with automated report generation location the alleged nature and severity of defects in pipeline statements of detected defects of metal;

- documenting and archiving of the results of the examination for certification of equipment;

- identify the location of the defect on the pipe in the angular coordinate system.

When using the known method (Patent RF №2062394, CL F 17 D 5/02, 1996) used two-component collinear flux-gate sensor of the magnetic field. The proposed method uses at least two to three of any type of sensor for measuring the magnetic field or one-component sensors of the magnetic induction vector.

In the case of a linear, extended object (in particular, pipeline) registration of magnetic field induction is carried out in a predetermined coordinate system within the defined measurement points selected and fixed aperture (base) sensors To2attached to the axis of the structure with a step dimension K1.

The location of the set of measurement points determined based on the diameter and depth of the pipeline using the coefficients K1To2and K3where

To1- measuring step (registration of magnetic field induction) = 0,2m;

To2- aperture (base) sensors selected from a ratio of 0.7 D≤2≤1,4 D, where D is iameter pipeline;

To3the depth of the pipeline or the shortest distance to the surface of the inspected metal, m

In the case of nonlinear, the extended object registered in the magnetic field is carried out in a fixed coordinate system. When this check-in is possible at different mutual arrangement of the sensors and their random orientation relative to the object (coplanar or collinear).

To clarify the angular location of the defect on the circumference of the pipe the distance between the sensors is chosen equal To2step angular scan K1should be no more than 30°to ensure the specified accuracy of the calculations.

For each point measurements in increments of K1constitute a second rank tensor whose components are the magnetic field gradients

Thereby carry out the formation of matrix distribution of the gradient magnetic field per unit surface area of the pipeline within the boundaries of the measured section.

The presence and magnitude of the anomalies of the magnetic field (local remote hub stress) at a given point is determined on the basis of comparison between a value of the increment of the module of the vector of the magnetic field of the Earth (magnetic moment). The method of calculation of these Velikanova on the dipole approximation remote hub, as described in the literature [Gvishiani, ABB. "On a simplified solution of the inverse problem of calculating the stresses in the pipe wall by magnetic fields of the scattering on the basis of nonlinear models of the magnetoelastic effect"; A.A. Dubov, V.G. Kuliev "features of stray fields near magnetized and strained ferromagnetic steel tubes with defective areas"]. The solution of the problem of the magnitude of the magnetic moment is obtained system of algebraic equations, the solution of which, in particular, are described in U.S. patent No. 4309659, CL G 01 V 3/40.

Fixation of the generated values of the anomalies of the magnetic field at each given point is held for subsequent comparison with other calculated values within a discrete area to select anomalies in the stress-strain state, deviating from the background values [magnetic fields].

The location of the defect of the metal based on the results of processing information carried out by the maximum level of concentration of the magnetic field (anomalies of the stress-strain state when compared to the previous fixed values.

The ability of the method is confirmed by the following example, but is not limited to them.

Example.

Carry out the registration information si is the subject of two three Hall sensors of magnetic field on the axis of the underground gas pipeline with a diameter of 1420 mm with pre-selected step of measuring 0.18 m and the sensitivity of the measurement - 10-8TI. The depth of the pipeline was 3.5 m Coefficients installation: K1= 0,18, K2=1,1,3=3,5. On a plot of length of 3000 m was just 3000/0 .18 = 16666 of measurement points. The results of registration remain in the memory storage device.

For each measurement point are the tensor of the second order components of which are the gradients of the magnetic induction vector. Calculate the value of the local remote hub voltage for all measurement points using the solution of a system of algebraic equations, described in U.S. patent No. 4309659, CL G 01 V 3/40.

The obtained information on the maximum values of the local anomalies are compared with the information stored in the memory storage device.

In the measuring point at a distance of 2350 m from the beginning of the plot, when the threshold is exceeded, the magnitude of the local anomalies over background values by more than 3.5 times during the 7 previous measurements, make a conclusion about the presence of 2-anomalies of the stress-strain state of metal defects)at a distance of 2350 m from the beginning of the site surveys of the pipeline.

Hold the opening of the pipeline (sortowanie) at the specified point anomalies of the magnetic field, conduct the arbitration radiography (definition of geometric parameters) 2 local corrosion defects cracks corrosion stress cracking (SCC) or stress-corrosion defects (Figure 2).

Based on the results of the pit measurements compare the variances of the magnitude of the anomaly from background values with the parameters of the real defect (crack SCC) and carry out calibration of the device.

Based on this mapping identifies the criteria the magnitude of deviations from background values, indicating the presence of a defect, component, in this case, 3-10 (time). On the basis of this value, perform a further selection of defects.

Identified on the section of the pipeline in 300-330 m from the starting point of the survey anomaly more than 100-fold above the background noise. Make a conclusion about the presence of this dangerous point defect SCC. Subsequently, in this place there was an explosion due to SCC (Fig. 3).

Figure 1 shows the General diagram of the device.

Figure 2 presents a photograph of pipes with defects of type "dint" and the results of data processing for this pipe is obtained by applying the proposed Method and device"is a distribution diagram of stress-strain state (graph-the magnetogram). On the magnetogram reflected the values of the background magnetic field and the maximum value of remote local hubs - the anomalies of the magnetic field, the cat who are identified as defects in the metal pipe in the form of dents different depths.

Figure 3 presents the results of information processing in the form of magnetograms with the anomaly, presumably paired with a dangerous defect - crack corrosion stress cracking (SCC) on the section of the pipeline with the subsequent explosion due to SCC.

4 shows an example of detecting the location of a defect of the metal pipe tie-in camera start-taking in the form of a tube-manometer and plunger) in the angular coordinate system.

Device for contactless detection of the location and nature of defects in metallic structures has a system of sensors 1 reception, a quartz oscillator 2, 3 frequency divider, analog-to-digital Converter 4, the control unit 5, the threshold block 6, block 7 sound and light alarm, automatic indicator 8 battery discharge, block 9 calculation of magnetic field gradients, the unit 10 to display information segment storage unit 11, unit 12 controls the recording unit 13 situational bindings, block 14 satellite absolute geolocation GPS that can record information concurrently with process maps and exact binding on district, block 15 select a segment of the recording,

Unit 9 can be performed, as in U.S. patent No. 4309659, CL 324-345, publ. G., the block 11 may be performed as in the patent 2037888, CL G 11 In 5/09, publ. G., the block 12 may be made, as in the author's certificate of the USSR No. 993242, CL G 06 F 3/06, publg., unit 13 can be performed, as in the testimony of the Russian Federation No. 13108 useful model class. G 06 F 17/30, publ. 2000.

The device works in the following way:

Registered gradients in the magnetic field line sensors 1 system, representing some three-component sensors in orthogonal directions or more single-component sensors of magnetic induction module (quantum analyzer with optical pumping).

Using analog-to-digital Converter 4, the signals are digitized and serve as initial conditions for block 9, and remembered a segment of the storage device 11. The frequency of the analog-to-digital Converter 4 defines the quartz oscillator 2 via the frequency divider 3. The management segment of the storage device 11 is performed by block 15. The signal recording unit 15 outputs the block 12.

Information processing is performed by the block 9. The use of unit 6 and unit 7 allows the indication of deviation indicators from background levels, and notify the operator in real time.

Due to the presence of the proposed device unit 10, a storage device 11, block 9 and comparison of current information with these blocks with informatieve unit 6 provides a graphical display in real time mode and alarm unit 7, thereby increasing the accuracy of location and risk assessment of identified defects. In addition, the unit 10 displays the current battery level 8.

The presence of the proposed device, the block 13 and block 14 provides a record of information in parallel with technological and situational schemes and contributes to a more accurate bound on the ground. This allows to clearly identify the location of the defect relative to the ground point with the established bindings on the ground in absolute geographical coordinates of further registration in the database for certification of equipment.

The possibility of using the sensor module to the magnetic field (quantum analyzer with optical pumping) provides increased sensitivity check for defect detection of underground structures with minor levels of mechanical stresses (low working pressures and large depth).

Given that the sensor system of registration is made in the form of several related sensors with the possibility of circular rotation above the surface of the controlled pipeline, it is possible to identify the location of the defect on the pipe in the angular coordinate system.

The execution of the block entries in the form of individual segments allows osushestvlyaetsya information in the form of individual portions. This enables the retention of independent pieces of information in non-volatile memory, helps to speed up the processing of current information in real time and saves power consumption during power off of the device.

Thus, the present invention allow for the prediction of the location of defects in metal structures by measurements and rapid calculations in real-time visualization of the obtained information in the form of graphs-magnetograms, to evaluate the nature and severity of the defect, provide automated forming conclusions about the location, nature and severity of defects, for example, pipelines, allow for automatic processing, transcribing, and archiving the results of the examination for certification (accumulation of information about the technical condition of the equipment).

In addition, the following is achieved:

adaptability for monitoring of dangerous sections of the pipeline;

reducing the risk of operational structures through timely detection of accidents and dangerous defects, prevent accidents due to corrosion, bio-corrosion or SCC, in particular, pipelines, i.e. provides the strength of metal structures.

1. The contactless way the neck is ing the presence and location of defects in metal pipelines including the measurement above the pipeline induction magnetic field, characterized in that at given points in the move process, carried out measurements of the magnetic field vectors in rectangular coordinates, at least two three-component sensors are tensor magnetic field gradients by matrix transformation spend processing the received information, the results of processing to determine a background value and deviations from this value, the difference of which on a given criterion value from the background value judgments about the presence and location of defects in metal pipes and build the magnetogram indicating the location of defects.

2. Device for contactless detection of the presence and location of defects in a metal piping system containing sensors recording magnetic field that is connected with the analog-to-digital Converter, a crystal oscillator, connected through a frequency divider with analog-to-digital Converter, a control unit, the block threshold level, coupled with block sound and light indication, automatic indicator battery discharge, characterized in that it further comprises a display unit information, the computing unit of magnetic field gradients, block situational binding and block absolute geographical is some binding, the segment of the storage device, the block select record segment and the control unit of account, while the control unit is connected to the unit case bindings, block absolute geo-referencing, the block select record segment and the control unit account connected with the computing unit of magnetic field gradients, the block select record segment is connected to the segment of the storage device connected via the computing unit of magnetic field gradients with a block display information connected with a power threshold level and automatic indicator battery discharge, analog-to-digital Converter connected to the computing unit of magnetic field gradients.



 

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