RU2272248C1 - Method for determining local portions of main pipelines with maximal deformation - Google Patents

Abstract

FIELD: technology for determining local portions of main pipelines with maximal deformation.

SUBSTANCE: method includes measuring oscillations of pipe in area of chambers of launch and receipt, oscillations of body at its immobile state, frequencies and coefficients of damping of fading oscillations are determined for body acceleration as well as transition process time during passage of junctions for selection of spectral analysis distance, spectral characteristics of acceleration signals are estimated for vertical direction of body between junctions, amplitudes level is excluded which is equal to noise in form of pipe and body oscillations at its immobile state, and also pulsing of as pressure; at discontinuous frequencies maximal resonance values are detected for components of Fourier decomposition of acceleration signals, frequencies of three forms of pipe oscillations are detected at representative portions, their positions are determined at route of main pipeline as well as their oscillation amplitudes.

EFFECT: possible estimation of vertical and horizontal deformations of pipelines.

3 cl, 8 dwg

Description

The method relates to instrumentation, in particular to the field of control of pipes and is intended to assess the values of their vertical and horizontal deformations.

Known inertial monitoring system of pipelines (US Patent No. 4945775, MKI G 01 C 9/06, 1990), which implements the following method:

1) the system passes through the pipeline and measures the dynamic characteristics of the carrying shells inside the pipeline relative to the inertial coordinate system in the space of the pipeline.

2) digital signals of measurements of dynamic characteristics are recorded inside the carrier means.

As the dynamic characteristics are measured by accelerometers and gyroscopes, accelerations and orientation angles of the carrier means in three directions, the speed and relative orientation of the carrier means in the pipeline by a system of ultrasonic sensors. Seams are detected using a microphone, analog signals are filtered, converted to digital and dynamic characteristics are calibrated along the seams of the pipeline.

The disadvantage of this method is the low accuracy of determining local displacements of pipelines due to the departure of gyroscopes.

There is a method in a device for determining and recording geometric parameters of pipelines (Patent RU No. 2102704, MKI G 01 B 17/02, BI No. 2, 1998). This patent implements the following method:

1) an in-tube inspection projectile is passed inside the pipeline;

2) a three-component angular velocity meter and a three-component apparent acceleration meter, measured in the coordinate system associated with the in-tube projectile, three components of the absolute angular velocity and three components of the apparent acceleration;

3) increments of the projectile path are measured with an odometer, with ultrasonic sensors — its position relative to the walls of the pipeline;

4) the measurement results are recorded in the memory of the calculation and registration device, and then converted into the current geographical coordinates of the location of the projectile and the angles of its orientation, as well as the radii of curvature of the longitudinal axis of the pipeline in the vertical and horizontal planes.

The disadvantage of this technical solution is the lack of a method for determining the effects of external and internal factors on the accuracy of determining local displacements of gas pipelines, identifying and predicting dangerous sections of pipelines, and compensating for the errors of the navigation system that accumulate over time due to correction from other systems.

The closest in technical essence and the achieved effect is the selected as a prototype method for determining local displacements of pipelines (Patent RU 2206871, G 01 B 17/02, G 1 N 29/04, BI No. 17, 2003)

This patent implements a method for determining local displacements of main pipelines using in-pipe inspection shells, including determining, using an inertial orientation and navigation system, the coordinates of the longitudinal axis of the pipeline, the angles and radii of its curvature in horizontal and vertical planes, while recording this information and the current time in memory the on-board computer as a function of the distance traveled, determined using odometers, and the number of welds and distance between them, with subsequent processing of the recorded information on a stationary computer, an in-tube inspection projectile is passed n times through the same section of the pipeline at time intervals characterized by different established temperature and weather conditions, and with each pass three-dimensional coordinates are determined and recorded in the on-board computer memory the longitudinal axis of the pipeline, the angles and radii of its curvature as a function of the current time and distance traveled, instantaneous temperature and profile around pipe at least 8 points at equidistant points, the gas pressure on the front and rear walls of the in-pipe inspection shell, and then after the “n” passes of the in-pipe inspection shell, using the stationary computer, the increments of all measured parameters relative to the corresponding parameters of the first passage are determined, as well as temperature gradients in the horizontal and vertical planes for the same points of welds and markers installed on the pipeline section and tied to the horizon plane but. In addition, according to the above method, a family of displacement graphs of three coordinates of the longitudinal axis of the pipeline, angles and radii of its curvature in the vertical and horizontal planes is constructed as a function of the same points depending on the pass number of the in-tube inspection projectile, which is a family parameter, and the locations of antinodes and nodes of displacement graphs are found , which establish critical points of mechanical stresses that cause stress corrosion of the pipeline, and for these points, which are combined with marker devices, including GPS, when processing information of an in-tube projectile on a stationary computer, the geographical coordinates of the corresponding critical points are determined, determined on the one hand using GPS, and on the other hand, using the inertial orientation and navigation system, shell odometer wheels and pipeline welds and the revealed difference of the three coordinates of the corresponding critical points determines the drift parameters of the inertial system, according to which a correction is made to its functioning algorithms and calculating increments. Moreover, in the above method, the family of graphs is performed in the form of a regression function for part of the critical points of the same name, which are combined with the reference points at which the temperature regime of the pipeline is measured

- коэффициенты; ΔР - градиент давления между передней и задней стенками; Р - давление в трубопроводе;

- коэффициенты влияния;where k is the measurement number; Δx _k , Δx _ko - increments of the measured parameters; ΔТ _g , ΔТ _в - temperature gradients at opposite points of the pipe in horizontal and vertical planes; T is the average temperature for measurements lying in the same circle;

- coefficients; ΔР - pressure gradient between the front and rear walls; P is the pressure in the pipeline;

- coefficients of influence;

and in the time intervals between missed missiles, possible displacements of the axis of the pipeline from soil and wind loads are predicted by the statistical regression equation.

The disadvantage of this technical solution is the lack of a methodology for determining local sections of trunk pipelines with maximum deformation with a single pass of the projectile.

The task was to develop a method for determining local sections of trunk pipelines with maximum deformation and identifying sections of dangerous stresses from external and internal influences on the pipeline.

New in the proposed method is the measurement of pipe oscillations in the vicinity of the launch and reception chambers, the oscillation of the projectile when it is stationary, the spectral characteristics of acceleration signals in the vertical direction of the projectile, the exclusion of the amplitude level equal to the noise in the form of pipe and projectile vibrations when it is stationary, identification the maximum resonance values of the components of the Fourier expansion of the acceleration signals between the seams in the low-frequency region and determining the position of representative sections of the pipe by asse.

по формуле:This is achieved by the fact that in the method for determining local sections of trunk pipelines with maximum deformation using in-tube inspection shells, which includes determining with the help of a strap-down inertial system of orientation and navigation the three components of the absolute angular velocity vector and the three components of the apparent acceleration vector of the in-tube inspected projectile, gas pressure measurement on the front and rear walls of the projectile, determining with the odometer the increments of its path with recording in p crush the on-board computer of the entire amount of information, when passing the projectile along the pipeline section, the pipe vibrations are measured in the region of the launch and reception chambers, the projectile vibrations when it is stationary, the frequencies and damping coefficients of damped projectile acceleration oscillations and the transition process during the passage of the seams are measured, spectral characteristics are estimated acceleration signals in the vertical direction of the projectile between the seams, exclude the level of amplitudes equal to the noise in the form of vibrations of the pipe and the projectile when it is not the initial state, as well as gas pressure pulsations; at discrete frequencies, the maximum resonance values of the components of the Fourier decomposition of the acceleration signals are detected, the frequencies of three pipe oscillation modes are detected on representative sections, their positions on the main gas pipeline route and the oscillation amplitudes are determined

according to the formula:

- величина ускорения в вертикальном направлении; m_c - масса снаряда; m_T - масса отрезка трубы на двух опорах длиной l;Where

- the magnitude of the acceleration in the vertical direction; m _c is the mass of the projectile; m _T is the mass of the pipe segment on two supports of length l;

ω _with - the oscillation frequency of the projectile.

- жесткость снаряда, определяемая по периоду его затухающих колебаний T после взаимодействия со швом трубы.k _T - equivalent bending stiffness of the pipe segment; k _c is the stiffness of the projectile in the pipe; E is the elastic modulus of the pipe material; J is the moment of inertia of the pipe; λ _m - coefficient (22.4; 61.7; 121 for the first, second and third modes of vibration, respectively),

- the rigidity of the projectile, determined by the period of its damped oscillations T after interaction with the pipe seam.

In addition, the position of representative plots is revealed by soil maps and tilt angles of the earth's surface, tied to the geographical coordinates of the measured values, as well as by aerospace images.

The invention is illustrated by drawings.

Figure 1 presents a device for implementing the proposed method, figure 2 is a diagram of a model of a mechanical system "projectile-tube-soil", figure 3 is a spectrogram of the background acceleration in the vertical direction of the projectile when it is stationary, figure 4 - the layout of the open section of the pipeline, in Fig.5 - the change in the acceleration of the projectile in the vertical direction when passing through the pipeline, Fig.6 - the change in the acceleration of the projectile in the vertical direction when the cuffs with the seam interact, Fig.7 - spectrogram of acceleration in the vertical direction of the projectile during the passage of the open section of the pipeline, Fig. 8 is a spectrogram of acceleration in the vertical direction of the projectile when passing the section of the pipeline in the ground.

A device for determining and recording the geometric parameters of pipelines (Fig. 1) consists of a sealed container 1, elastic cuffs 2, rigidly fixed in the bow and tail of the container 1, a track sensor 3, a unit 4 of calculation and control and a recorder 5 located inside the container 1 Inside the container 1, a three-component gyroscopic meter 6 of angular velocity and a three-component meter 7 of apparent acceleration are rigidly fixed, the outputs of which are connected to the inputs of the unit 4 of calculation and control. Sealed container 1 should be considered in tight connection with the coordinate system OX ₁ ; OX ₂ ; OX ₃ (respectively, the longitudinal, normal and transverse axes of the device), ω _X1 , ω _X2 , ω _X3 - components of the absolute angular velocity vector of container 1; W _X1 , W _X2 , W _X3 are the components of the apparent acceleration vector of the sealed container 1, measured respectively by a three-component gyroscopic angular velocity meter 6 and a three-component apparent acceleration meter 7. Figure 1 also shows the wheels 8 of the sealed container 1 and the pipeline 9. The coordinate system Oξηζ is connected to the pipeline 9, and at the initial time, the coordinate systems Oξηζ and OX ₁ X ₂ X ₃ coincide. The device has a battery 10 and gas pressure sensors 11, a detection system for marker devices 12 with known geographical coordinates from GPS receivers. On the pipeline 9 between the seams 13 is installed a device for determining the oscillations of the pipe 14 (figure 4).

To implement the method using the proposed device, the coordinates of the marker points are determined in the form of reception launch chambers, air passage security taps on the gas pipeline route by aerospace methods or GPS receivers. A sealed container 1 with cuffs 2, wheels 8 and the battery 10 is turned on, is inserted into the pipeline 9 to the elements, blocks of the device 3-7, 11, 12. When the projectile is stationary, the pipe oscillation parameters are measured by device 14. When gas pressure is applied, container 1 starts move relative to the pipe 9. In this case, in the stationary state of the projectile and during movement, the readings of the track sensor 3, three-component angular velocity meters 6 and seemingly accelerated are recorded in the computing and control unit 4, the on-board computer 5 I 7, and the gas pressure sensor 11. When the container is removed from the chamber receiving the information is transferred to a standard PC and the track is constructed in the form of graphs distances along the meridian and parallel adjustment. In this case, the number of welds 13 is determined from the acceleration sensors 7 and the known distances between the corresponding reference points are taken into account, the inertial system drift parameters are determined, and then a correction is made to the algorithm for calculating the pipeline coordinates. When the container passes near the marker device, the readings from the marker detection device 12 are also recorded.

Representative sites are selected based on an analysis of the physical-geographical and geo-ecological conditions, i.e. hydromorphic sections with a small coefficient of pinching of the pipeline are selected (SNiP 2.05.06-85), from the hypsometric and soil maps, aerospace images of the main gas pipeline and the maximum resonance values of the components of the Fourier decomposition of the acceleration signals are revealed on them by the spectral characteristics of acceleration signals in the vertical direction. Exclude the level of amplitudes equal to the noise in the form of oscillations of the pipe and the projectile when it is stationary. The frequency of the damped and intrinsic undamped vibrations of the projectile is determined by the period and the logarithmic decrement of vibration damping after the projectile interacts with the seam. The values of the projectile stiffness K _c = ω ² m _c , the pipe length by formula (2) and the values of the three vibration modes of the pipe length by the formulas (1) - (3) are calculated. They are detected on the spectral characteristics and the values of the amplitudes of the vibrations of the pipe segment are determined by the formula (1).

The frequency of bending vibrations of a pipe section of a main gas pipeline with bilateral end fixing is determined by the formula (Birger I.A., Shorr B.F., Iosilevich GB, Strength Analysis of Machine Parts. Ref. M .: Mechanical Engineering. 1993, P.401 -402). Coefficients λ _m1 = 22.4; λ _m2 = 61.2; λ _m3 = 121 correspond to the first, second and third modes of vibration.

Oscillations of the projectile with the pipe at the end fixing (Fig. 4) (in air, washing in the ground) can be considered as oscillations of a system with two degrees of freedom. The oscillation frequencies of a projectile of mass m _c and a length of pipe (m _T ) are determined for the circuit in Fig. 2 in the form, (Timoshenko S.P., Young D.Kh., Unver W. Oscillations in engineering. M .: Mechanical Engineering, 1985 S.192-194).

- коэффициенты жесткости отрезка трубы и снаряда в трубе; m_T,с - масса отрезка трубы и снаряда.Where

- the stiffness coefficients of the pipe segment and the projectile in the pipe; m _{T, s} is the mass of the pipe segment and the projectile.

In the diagram (figure 2) K _∂1 , K _∂2 are the damping coefficients of the pipe and projectile vibrations, respectively.

The equivalent stiffness of a pipe segment under bending vibrations can be written as follows:

для трубы газопровода D_Y=1020±6 мм, D_В=1000 мм и l=5...15 м с первой формой колебаний λ_m1=22,4. Наши экспериментальные данные для снаряда СИТ-1200 показали, что k_c=3,1·10⁷ Н/м, а для СИТ-1000 - k_C=2,1·10⁷ Н/м.Calculations by the formula (5) show that

for a gas pipe D _Y = 1020 ± 6 mm, D _B = 1000 mm and l = 5 ... 15 m with the first waveform λ _m1 = 22.4. Our experimental data for the SIT-1200 projectile showed that k _c = 3.1 · 10 ⁷ N / m, and for the SIT-1000 - k _C = 2.1 · 10 ⁷ N / m.

Denote

.

.

.Then the expressions for the parameters of the system of the form (4) can be written as follows:

.

Formula (4) after expansion in a series of radical expression we present in the form:

For high crush rates

.

.

The kinematic excitation of the vibrations of the projectile is determined by the movement of the projectile through the pipeline with transverse seams with a height of N _m and is determined with harmonic vibrations as

,

,

here L _T is the length of the pipe segment between the seams; L _M is the distance between the cuffs; V _c - linear velocity of the projectile.

Force excitation of oscillations is determined by the pulsation of the gas in the linear part of the main gas pipeline. In this case, the level of gas pulsations at the outlet of the compressor station is determined by the frequency of 28.8 Hz, and the vibrations of the main pipelines (⌀426 mm} were 5 ... 7 mm / s at frequencies of 9 ... 10 Hz (Muschinkin A.Z. et al. . "Pulsation of the gas flow in technological pipelines at the outlet of the compressor station and in the linear part of the main gas pipeline // XI International Business Meeting" Diagnostics-2000, T.3. - 2001. - P.53-63).

The mass of the measuring unit (VOG-951, AK-6) is 6.5 kg, the magnetic screen of permalloy is 4.5 kg, the entire ITC-E24SB unit is 28 kg. If we consider the oscillations of the inertial block on the cantilever beam, then the frequency of natural vibrations of this mass on the console is determined in the form (Birger I.A. et al. Strength analysis of machine parts. Sp. 4th ed .: - M., Mechanical Engineering, 1993 , P.19).

- момент инерции сплошного круглого сечения; D=20 мм - диаметр стержня; l=260 мм - длина стержня.where k is a coefficient depending on the location of the supports and the nature of the load (for a cantilever beam with a force at the free end k = 3); E is the modulus of elasticity;

- moment of inertia of a solid circular section; D = 20 mm is the diameter of the rod; l = 260 mm - the length of the rod.

The calculation by the formula (7) shows that the oscillation frequency is 36.6 Hz. The results of experimental studies of the spectral density of signals from VOG-951 and accelerometers during projectile movement showed that such a frequency is present and is equal to 34.5 ... 36 Hz,

Figure 3 presents the spectrogram of the background acceleration in the vertical direction with a stationary projectile. The background signal is white noise, mainly lying in the range up to 0.001 g.

Figures 7 and 8 show graphs of spectrograms of frequencies obtained as a result of the passage of an SIT-1000 in-line inspection projectile on the route of the Parabel-Kuzbass gas pipeline, a section of a beam fastening pipe 7 m long, located in the air at a distance of 72,441.52-72447.45 m, and pipes in the ground at a distance of 151577.22-151586.00 m between the joints in the vertical direction. The following identified oscillation frequencies are observed:

- in the air (Fig. 7): the frequencies of the three shell oscillation modes f _c1 = 11.1 Hz (point M1), f _c2 = 12.8 Hz (point M2), f _c3 = 13.6 Hz (point M3) from pipe bending vibrations;

- in the ground (Fig. 8): the oscillation frequency of the projectile f _c = 13.5 Hz (point M _P );

The calculated values of the frequencies of the three forms of projectile vibrations from the bending vibrations of the pipe and the natural oscillation frequency of the projectile, determined by formula (2), were f _c1 = 11.1 Hz, f _c2 = 12.9 Hz, f _c3 = 13.5 Hz, f _c = 13.5 Hz, respectively.

On a section of the Algay-Mokrous gas pipeline route, measurements were taken of the signals from the projectile accelerometer unit and the pipe in the vicinity of the launch chamber of the SIT-1200 inspecting projectile at a distance of 35 km. The background level of the signals was 10 ^-6 g. The following resonant frequencies of bending vibrations were experimentally observed:

- a segment of a beam fastening pipe with a length of 6.1 m - 9.6; 10; 12.9 Hz with an amplitude of 3 · 10 ^-6 g.

- shell - 9.8; 11, 5; 13.5 Hz with an amplitude of 0.02 g.

Claims (3)

1. A method for determining local sections of trunk pipelines with maximum deformation using in-tube inspection shells, including determining with the help of a strap-down inertial system of orientation and navigation the three components of the absolute angular velocity vector and three components of the apparent acceleration vector of the in-tube inspection projectile, measuring the gas pressure at the front and rear the walls of the projectile, determining with the odometer the increments of its path with recording in the memory of the on-board computer of this amount of information when passing a projectile along a section of the pipeline, characterized in that the pipe oscillations are measured in the region of the launch and reception chambers, the projectile vibrations when it is stationary, the frequencies and damping coefficients of damped projectile acceleration oscillations and the transition process during the passage of the seams to select a distance are determined spectral analysis, evaluate the spectral characteristics of the acceleration signals in the vertical direction of the projectile between the seams, exclude the level of amplitudes equal to the noise in the form of the oscillations of the pipe and the projectile when it is stationary, as well as the pulsation of the gas pressure; at discrete frequencies, the maximum resonance values of the components of the Fourier decomposition of the acceleration signals are detected, the frequencies of three pipe vibration modes are detected in representative sections, their positions on the main gas pipeline route and the vibration amplitudes are determined by the formula:

Where

- the value of the acceleration of the projectile in the vertical direction; m _c is the mass of the projectile; m _T is the mass of the pipe segment on two supports of length l;

ω _with - the oscillation frequency of the projectile.

k _T is the equivalent bending stiffness of the pipe section; E is the elastic modulus of the pipe material; J is the moment of inertia of the pipe; λ _m - coefficient (22, 4; 61.7; 121 for the first, second and third modes of vibration, respectively),

- the rigidity of the projectile, determined by the period of damped oscillations T after interaction with the seam. 2. The method according to claim 1, characterized in that the position of the representative plots is revealed by soil maps and the angles of inclination of the earth's surface, tied to the geographical coordinates of the measured values. 3. The method according to claim 1, characterized in that the position of the representative sections is detected by aerospace images.

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