Determining the integrity of a pipeline wall

Abstract

The invention relates to an acoustic measuring transducer system (1) for determining the integrity of a pipeline wall (4) made of carbon steel, stainless steel, cast iron, or cement, having: at least two measuring transducers (3), each of which is configured to emit an acoustic wave in the direction of the pipeline wall (4) and detect an acoustic echo longitudinal wave generated by the pipeline wall (4) and an acoustic echo shear wave generated by the pipeline wall (4); and a control unit, which is connected to each of the measuring transducers (3) so as to transmit signals and which is configured to determine the integrity of the pipeline wall (4) using a change produced in the ratio between the speed of the acoustic echo longitudinal wave and the speed of the acoustic echo shear wave. The invention additionally relates to a computer-implemented method for an acoustic measuring transducer system (1).

Description

[0001] Determination of the integrity of a pipeline wall

[0002] Technical area

[0003] The present invention relates to an acoustic transducer system for determining the integrity of a pipeline wall made of carbon steel, stainless steel, cast iron or cement.

[0004] Furthermore, the present invention relates to a computer-implemented method for determining the integrity of a pipeline wall made of carbon steel, stainless steel, cast iron or cement.

[0005] Background of the invention

[0006] To date, inspection methods used for oil or gas pipelines and methods used for inspection of water pipelines are known. Oil or gas pipelines are made of carbon steel or stainless steel. Water pipelines are made of cast iron or cement. In oil or gas pipelines, ultrasound-based inspection methods result in a slight attenuation of the signal at a defect compared to the signal attenuation generated at a defect in a water pipeline. The defects also have different properties in oil / gas pipelines compared to those in water pipelines. In the case of defects in an oil or gas pipeline, there is usually no change in the material. In contrast, defects in cast iron or cement pipelines usually also result in a change in the material.

[0007] Description of the invention

[0008] The present object is to be able to determine the integrity of a pipeline in an improved manner compared to known methods. In particular, the present invention is intended to detect defects in pipelines that may be made of carbon steel or stainless steel, on the one hand, or cast iron or cement, on the other. In other words, it should be possible to determine defects in both types of pipelines using the same system / method.

[0009] The object of the invention is achieved by the features of the independent main claims. Advantageous embodiments are specified in the subclaims. To the extent technically feasible, the teachings of the subclaims can be combined arbitrarily with the teachings of the main and subclaims.

[0010] In particular, the object is achieved by an acoustic transducer system for determining the integrity of a pipeline wall made of carbon steel, stainless steel, cast iron, or cement. The transducer system comprises: at least one transducer configured to emit an acoustic wave in the direction of the pipeline wall and to detect an acoustic echo longitudinal wave generated by the pipeline wall and an acoustic echo shear wave generated by the pipeline wall; and a control unit signal-connected to the transducer, which is configured to determine the integrity of the pipeline wall based on an occurring change in a ratio between a velocity of the acoustic echo longitudinal wave and a velocity of the acoustic echo shear wave.

[0011] Furthermore, the problem is solved by a computer-implemented method, in particular an acoustic transducer system, for determining the integrity of a pipeline wall made of carbon steel, stainless steel, cast iron, or cement. The method comprises the following process steps:

[0012] Emitting, by means of at least one transducer, an acoustic wave in the direction of the pipe wall and detecting, by means of the at least one transducer, an acoustic echo longitudinal wave generated by the pipe wall and an acoustic echo shear wave generated by the pipe wall; and

[0013] Determining, by means of a control unit signal-connected to the transducer, the integrity of the pipeline wall based on an occurring change in a ratio between a velocity of the acoustic echo longitudinal wave and a velocity of the acoustic echo shear wave.

[0014] It is preferred that the sequence of process steps can be varied, unless technically required in an explicit order. However, the aforementioned sequence of process steps is particularly preferred.

[0015] Advantageous aspects of the claimed invention are explained below, and preferred modified embodiments of the invention are further described below. Explanations, particularly regarding advantages and definitions of features, are essentially descriptive and preferred, but not limiting, examples. If an explanation is limiting, this will be expressly stated.

[0016] The modified embodiments described below may be embodiments of the transducer system and embodiments with corresponding method features of the computer-implemented method.

[0017] It has been shown that the invention can be used to detect graphitization in cast iron pipelines and leaching in cement pipelines. At the same time, defects in pipelines made of carbon steel or stainless steel can be detected. This is particularly important because, for example, the defects have different properties. In oil / gas pipelines, corrosion is synonymous with material loss. Corrosion does not change the material properties. Likewise, there is no change in the material density, speed of sound, or attenuation. A slight material attenuation of the ultrasonic waves makes it possible to measure the wall thickness. Corrosion can be detected by ultrasonic wall thickness measurement. In this case, the speed of sound is constant. In water pipelines, corrosion is not synonymous with material loss. The material properties change with corrosion. In particular, there is a change in the material density.This changes the speed of sound and attenuates the ultrasonic signal.

[0018] In particular, high material-related absorption and diffusion of ultrasonic waves makes wall thickness measurement difficult. In other words, the detection of corrosion with ultrasound is difficult due to variations in the speed of sound and no variation, or due to variations in the wall thickness.

[0019] The detection of a defect with a transducer is carried out, for example, using a pulse-echo method (PE method or PE mode). In this case, the same transducer receives ultrasonic echoes reflected from a pipeline wall, which previously emitted ultrasound in the direction of the pipeline wall. In other words, to determine the integrity of the pipeline wall based on an occurring change in the ratio between the velocity of the acoustic echo longitudinal wave and the velocity of the acoustic echo shear wave, the use of a single transducer for emitting and detecting is sufficient. According to a modified and preferred embodiment, at least two transducers are involved in the measuring process. The method is possible with one transducer.In a minimum configuration of the modified and preferred embodiment, both transducers should be operated to emit ultrasound toward the pipeline wall and each detect an ultrasonic echo.

[0020] A control unit is connected to the at least one, in the modified embodiment to the at least two, measuring transducers. Preferably, the control unit is connected to each of the measuring transducers involved in the measuring process. The control unit processes the measurement signals corresponding to the ultrasonic echoes. The control unit compares the respective acoustic echo longitudinal waves and the acoustic echo shear waves. The control unit sets a ratio between the velocities of the echo longitudinal wave and the echo shear wave. It calculates this ratio for each measuring transducer involved in the measuring process and which receives an ultrasonic echo. If a change in this velocity ratio occurs, the control unit can determine the integrity of the pipeline based on this.Minimally, the integrity of the pipeline wall can be determined using only one transducer, based on an occurring change in a ratio between a velocity of the acoustic echo longitudinal wave and a velocity of the acoustic echo shear wave.

[0021] If only the pitch-catch mode (PC method or PC mode) is used, at least three transducers would be required for the measurement process. For example, a first transducer could emit ultrasound toward the pipe wall, while the other two transducers could detect ultrasonic echoes.

[0022] It is also possible to combine PE mode and PC mode. In this case, a minimum of two transducers can be used, with one of the two transducers emitting and receiving ultrasound, and the other of the two transducers only receiving.

[0023] Furthermore, it is possible to identify the pipeline material type and quality, as well as the weld type and degree, and hard spots. The invention is applicable to ultrasonic inline inspection (ILI) inspections, both for low-frequency ultrasound and high-frequency ultrasound.

[0024] The measuring transducer(s) are preferably standard measuring transducers. In other words, the standard measuring transducers are standard probes. A standard probe is a probe that emits ultrasound in the form of longitudinal waves perpendicular to the surface of the pipeline in the direction of the pipeline. The measuring transducers are particularly preferably arranged as a standard beam sensor array. An ultrasound exit surface / entrance surface of the measuring transducer can be circular. The exit surface can be flat or have a concave or convex curvature. The measuring transducers can also be annular. Combinations of measuring transducers can exist, for example in the form of structural units that can be installed together in a carrier body, in which a first measuring transducer is circular and a second measuring transducer encloses the first, circular measuring transducer in a ring.It is also conceivable for several transducers to enclose each other in a ring. It is also conceivable for several units of circular and ring-shaped transducers to be arranged in one or more circles around a common center point.

[0025] The carrier body can have alignment means for aligning itself with respect to the pipeline such that a straight line passing through an elongated region of maximum intensity of the ultrasonic beam emitted by the transducer's exit surface, i.e., the ultrasonic beam cone, is parallel to a surface normal of an inner surface of the pipeline wall directed toward the interior of the pipe. However, the straight line and the surface normal of the pipeline wall have a maximum alignment deviation of 5 degrees from each other.

[0026] Alternatively or in addition to alignment means of the support body, the or each of the transducers can be aligned accordingly on the support body. Alternatively or additionally, transducers can be aligned in groups relative to the support body. This can be achieved, for example, by the transducer support. Accordingly, either the transducer support / each of the transducer supports and / or the support body has alignment means suitable for aligning the transducer(s) that emit ultrasound toward the pipeline wall relative to the pipeline wall.

[0027] In this context, reference is often made to a pipeline. This can generally be any workpiece made of carbon steel, stainless steel, cast iron, or cement.

[0028] Preferably, the ultrasonic echo(es) detected are normal ultrasonic pulse echoes. Such an ultrasonic pulse echo is the ultrasonic echo detected by a transducer that is parallel to a normal to a pipeline surface or with a maximum deviation of five degrees from the normal. An ultrasonic pulse echo is a pulsed echo. The echo is generated by pulsed ultrasound. The ultrasonic pulse echo can also be a chirped signal.

[0029] Preferably, the transducers of the system are configured and arranged to perform a phased array test on the pipeline. The combination of mechanical scanning and electronic beam steering in phased array testing increases flaw detection because the sound waves are irradiated from different angles of incidence. Sampling phased array acquires data by exciting cylindrical or spherical waves that propagate in all directions. A high probability of detection while simultaneously covering a large area of ​​the pipeline being examined can be achieved with single-shot phased array scanning. The returning ultrasonic echo signals from a single transducer irradiation are acquired by each individual transducer.The received signals are then used in particular to reconstruct A-scans for one or more arbitrary angles and / or focal depths.

[0030] Preferably, a lower frequency for ultrasound in a range from 100 kHz up to and including 2000 kHz is used. In particular, ultrasound with a central frequency in the range from 300 kHz to 1200 kHz is used. This frequency range is a low-frequency ultrasound transducer (LFUT) frequency range. The preferred frequency range is particularly suitable for detecting graphitization in cast iron water pipes or leaching in cement pipes from the inside using an ILI tool. Compared to high-frequency ultrasound transducers (HFUT), LFUT has the advantage of lower attenuation and penetration capability due to its long wavelength.

[0031] Particularly when using appropriate settings for the transducer(s) in PE mode and PC mode, information about the distance, wall thickness, corrosion area, and changes in the material properties of the pipelines can be determined. The same principle could also be used to detect defects in oil-bearing pipelines, especially oil pipelines, where deposits or scale have accumulated on the inner wall of the pipeline.

[0032] According to a modified embodiment, an acoustic transducer system is provided for determining the integrity of a pipeline wall made of carbon steel, stainless steel, cast iron, or cement. The transducer system comprises: at least two transducers, each configured to emit an acoustic wave toward the pipeline wall and to generate a

[0033] to detect an acoustic echo longitudinal wave generated by the pipeline wall and an acoustic echo shear wave generated by the pipeline wall; and a control unit signal-connected to the respective transducers, which is configured to determine the integrity of the pipeline wall based on an occurring change in a ratio between a velocity of the acoustic echo longitudinal wave and a velocity of the acoustic echo shear wave.

[0034] Furthermore, according to a modified embodiment, a computer-implemented method is provided, in particular an acoustic transducer system, for determining the integrity of a pipeline wall made of carbon steel, stainless steel, cast iron, or cement. The method comprises the following method steps:

[0035] Emitting, by means of at least one of at least two measuring transducers, an acoustic wave in the direction of the pipeline wall and detecting, by means of the at least two measuring transducers, an acoustic echo longitudinal wave generated by the pipeline wall and an acoustic echo shear wave generated by the pipeline wall; and determining, by means of a control unit signal-connected to each of the measuring transducers, the integrity of the pipeline wall based on an occurring change in a ratio between a speed of the acoustic echo longitudinal wave and a speed of the acoustic echo shear wave. The two modified embodiments described above have the advantage that an amplitude of the shear wave mode generated with multiple measuring transducers is increased compared to an amplitude of the shear wave mode generated with a single measuring transducer.In other words, using at least two transducers, a larger amplitude of the shear wave mode can be generated and thus a sound velocity ratio can be better evaluated.

[0036] According to a modified embodiment, the control unit is configured to convert the acoustic echo longitudinal wave and the acoustic echo shear wave from a normal ultrasonic pulse echo into modes, and to determine the change in the ratio from the modes of the acoustic echo longitudinal wave and the acoustic echo shear wave.

[0037] From these modes, the respective velocities for the echo longitudinal wave and the echo shear wave are determined. In other words, the control unit is configured to convert the acoustic echo longitudinal wave and the acoustic echo shear wave from the normal ultrasonic pulse echo into modes, and to determine the change in the ratio from the modes of the acoustic echo longitudinal wave and the acoustic echo shear wave.

[0038] Mode conversion means that the measurement signal, comprising the echo longitudinal wave and the echo shear wave, is represented as a curve. The measurement signal is represented as a temporal progression of the received ultrasonic echo. In other words, it is a representation of the signal as an A-scan.

[0039] The modified embodiment described above has the advantage that the signal can be processed quickly. Information about the speed ratio can be obtained in a time-efficient manner.

[0040] According to a modified embodiment, the control unit is configured to determine the integrity of the pipeline wall based on an occurring change in the ratio A between the velocity of the acoustic echo longitudinal wave and the velocity of the acoustic echo shear wave, which is defined as follows: where cl is the velocity of the acoustic echo longitudinal wave, ct is the velocity of the acoustic echo shear wave, Tt is the arrival time of a mode of the echo shear wave, and TI is the arrival time of a mode of the echo longitudinal wave. In other words, Tt is the arrival time of the acoustic echo shear wave mode, and TI is the arrival time of the acoustic echo longitudinal mode.

[0041] The arrival time TI is the arrival time of the acoustic echo longitudinal mode at the transducer. The arrival time Tt is the time at which the acoustic echo shear wave mode measurably arrives at the transducer. In other words, the arrival time TI is the time at which a steady state is reached for the acoustic echo longitudinal wave. Tt is the time at which the acoustic echo shear wave mode is identifiable in the measurement signal.

[0042] The proposed ratio A is advantageously simple and therefore can be determined with little computational effort.

[0043] According to a modified embodiment, the transducer system comprises a plurality of transducers. The control unit is configured to represent the change in the ratio between the velocity of the acoustic echo longitudinal wave and the velocity of the acoustic echo shear wave for each of the transducers as a matrix element of a matrix, wherein one dimension of a matrix row corresponds to the number N of transducers minus 1.

[0044] For example, the matrix can be evaluated directly and easily with such a representation. For example, an image can also be created based on such a matrix, in which different colors are selected depending on the magnitude of the ratio. According to a modified embodiment, the transducer system has a plurality of transducers, wherein in a pulse-echo mode of the transducer, the control unit is configured to create six matrices with N columns for each of the transducers, wherein the number N of columns corresponds to the number of transducers, wherein each of the columns has at least one entry, wherein a first matrix has as entries travel time measured values ​​Time_RF, wherein in a left column the travel time measured value of a fastest pulse echo corresponds, a second matrix first-degree Fourier transforms of the travel time

[0045] measured values, a third matrix Fourier transforms of second degree of the runtime

[0046] measured values, a fourth matrix has amplitude measured values, a fifth matrix has first-order Fourier transforms of the amplitude measured values, and a sixth matrix has second-order Fourier transforms of the amplitude measured values.

[0047] It has been shown that the proposed processing in matrices is a well-suited starting point for finding a deviating velocity ratio, which in turn can be used to identify the defect. In principle, any of the six matrices mentioned above can be used to determine the velocity ratio. This provides independent starting points for further processing by the control unit.

[0048] According to a modified embodiment, the transducer system comprises:

[0049] • at least two measuring transducers, a carrier body and at least one measuring transducer carrier,

[0050] • wherein the at least two measuring transducers are connected to the measuring transducer carrier,

[0051] • wherein the at least one transducer carrier is designed to be pivotable and / or movable away from and / or toward the carrier body. The above-described design has the advantage that individual units can be formed, each of which is separately evaluated to determine the velocity ratios. In this case, a group of transducers can advantageously be aligned with respect to the pipeline via the transducer carrier.

[0052] The transducer system can comprise transducers installed on the transducer carrier(s) and transducers arranged directly on a carrier body. The carrier body is elongated, and the carrier body is preferably cylindrical. Other shapes of the carrier body, such as a pentagonal, hexagonal, or N-sided cross-section, are conceivable.

[0053] Preferably, a plurality of measuring transducers are arranged on a surface of the carrier body in the direction of movement of the measuring transducer system, or on both sides at respective end regions, i.e., without a measuring transducer support, they are rigidly connected to the carrier body. The measuring transducers can be rigidly connected to the carrier body in a chain-like manner, enclosing the carrier body. Further away from the end regions of the carrier body, the carrier body can then have measuring transducers arranged on measuring transducer supports / on a measuring transducer support. If the rigidly arranged measuring transducers have detected a defect, the measuring transducers arranged on the measuring transducer support can then be aligned with respect to the pipeline wall, whereby the properties of the defect can advantageously be determined more precisely.

[0054] According to a modified embodiment, the measuring transducer system comprises at least one measuring transducer assembly, wherein the measuring transducer assembly comprises a plurality of measuring transducers, wherein the measuring transducers are arranged in at least one circle, wherein at least one further measuring transducer is arranged in a circle center.

[0055] A variety of transducer arrangements can be provided in circuits.

[0056] The arrangement described above advantageously results in an excellent signal-to-noise ratio, while at the same time a very good determination of the speed ratios can be achieved.

[0057] Alternative arrangements of transducers are conceivable. For example, one emitting transducer and one detecting transducer can be provided per assembly, i.e., per device that can be installed in the carrier body or per transducer carrier.

[0058] Alternatively or additionally, several ultrasonic emitting transducers and one ultrasonic echo detecting transducer arranged centrally to the ultrasonic emitting transducers can be provided per assembly, ie per device that can be installed in the carrier body and / or per transducer carrier and / or per transducer assembly.

[0059] Alternatively or additionally, a detecting transducer and an emitting transducer annularly enclosing the detecting transducer can be provided for each structural unit, i.e., for each device that can be installed in the carrier body and / or for each transducer carrier and / or for each transducer structural unit. In other words, a second transducer is formed by a ring with a single-element exit surface, and an entry surface of a first transducer is arranged within the ring. Conversely, it is possible for a first transducer to be formed by a ring with a single-element exit surface, and an entry surface of a second transducer is arranged within the ring.

[0060] Depending on the operating mode, the transducers can operate in PE mode or PC mode as the first transducer or as the second transducer.

[0061] The first transducer is controlled to operate in PE mode, as well as in PC mode. In addition, the first transducer can be controlled simultaneously in PC mode and PE mode. The second transducer is controlled in PC mode to detect the ultrasonic echo reflected from the pipeline wall. Alternatively or additionally, the modules are arranged in a circle. The number of detecting transducers arranged in the center and / or emitting transducers arranged in the circle can be adjusted depending on the desired signal-to-noise ratio, the properties of the pipeline, and the size of the transducer system. The emitting transducers can also be arranged in several circles of different diameters around the detecting transducer(s).

[0062] As an alternative to the aforementioned embodiments, the detecting transducers are arranged in circles around one or more ultrasonic-emitting transducers. This can be implemented in a single unit or in multiple units according to the principles described above.

[0063] The transducer modules are arranged, for example, on a transducer carrier or directly on the carrier body.

[0064] Short description of the drawings

[0065] The invention will be explained in more detail below with reference to preferred embodiments and the accompanying drawings. The term "figure" is abbreviated to "Fig."

[0066] The drawings show

[0067] Figure 1a is a schematic view of a transducer system according to an embodiment;

[0068] Figure 1b is a schematic view of the transducer system according to another

[0069] Implementation example;

[0070] Figure 2a is a schematic view of a module with four measuring transducers to illustrate an embodiment;

[0071] Figure 2b is a schematic view of a wavefront generated by a module comprising a plurality of transducers; Figure 2c is a schematic view of a sector image for reconstruction according to an embodiment;

[0072] Figure 3a is a schematic plan view of an ultrasonic entrance / exit surface of a structural unit of a transducer system according to one embodiment;

[0073] Figure 3b is a schematic plan view of an ultrasonic entry / exit surface of a structural unit of a transducer system according to another embodiment;

[0074] Figure 3c is a schematic plan view of an ultrasonic entry / exit surface of a structural unit of a transducer system according to a further embodiment;

[0075] Fig. 4 is a schematic view of the transducer assembly according to a preferred embodiment of the invention;

[0076] Fig. 5 is a schematic representation of a first simulation for determining a speed ratio; and

[0077] Fig. 6 is a schematic representation of a second simulation for determining a speed ratio.

[0078] Detailed description of the implementation examples

[0079] The described embodiments are merely examples that can be modified and / or supplemented in a variety of ways within the scope of the claims. Each feature described for a specific embodiment can be used independently or in combination with other features in any other embodiment. Each feature described for an embodiment of a specific claim category can also be used correspondingly in an embodiment of a different claim category.

[0080] Figures 1a and 1b show two possible embodiments of the acoustic transducer system 1. The acoustic transducer system 1 comprises a carrier body 2. A plurality of transducers 3 configured as ultrasonic transducers are arranged on the carrier body 2. In other words, the transducers 3 are ultrasonic sensors. These ultrasonic sensors can comprise piezoelectric elements for generating the ultrasound. The carrier body 2 can, for example, be cylindrical.

[0081] Each of the transducers 3 has an exit surface 3a, at which the transducer 3 emits ultrasonic beams toward a pipe wall 4 of a pipeline. The exit surface 3a of the transducers 3 can be circular. The exit surface 3a can be flat or have a concave or convex curvature.

[0082] Each of the transducers 3 is attached directly to the carrier body 2 (see Figure 1a) or indirectly via a transducer carrier 5 to the carrier body 2 (see Figure 1b). It should be noted that the size ratios between the transducer carrier 5 and the carrier body 2 do not have to correspond to the size ratios shown in Figure 1b. In the case of an arrangement on the transducer carrier 5, for example, several transducers 3 can be arranged as a group of transducers 3 on the transducer carrier 5.

[0083] The transducer carrier 5 can then move the transducers 3 together as a group. The transducer carrier 5 is designed to be pivotable and / or movable away from or toward the carrier body 2. The transducer system 1 can also include transducers 3 installed on the transducer carrier 5 / multiple transducer carriers 5 and transducers 3 arranged directly on the carrier body 2.

[0084] The exit surface 3a of each transducer 3 is arranged perpendicular to the pipeline wall 4 on a surface of the support body 2 or in / on the transducer support 5. Each of the exit surfaces 3a is arranged and configured such that, when the support body 2 is aligned longitudinally with the pipeline, i.e., a longitudinal axis of the support body relative to a longitudinal axis of the pipeline, a straight line G3a extending through a region of maximum intensity of the ultrasonic beam emitted by the exit surface 3a is parallel to a surface normal N4a of an inner surface 4a of the pipeline wall 4 directed toward the interior of the pipe. The system 1 facilitates an examination of the pipeline wall 4 with alignment tolerances of the region of maximum intensity of the ultrasonic beam extending through the straight line G3a of up to five degrees relative to the surface normal N4a of the pipeline wall 4.A parallel alignment of G3a and N4a is advantageous if the inner surface, i.e., the inner surface 4a, of the pipe wall 4 and the exit surface 3a extend parallel to one another or are aligned with an alignment tolerance of a maximum of 5 degrees. The support body 2 can have alignment means for aligning itself accordingly with respect to the pipe. Alternatively or additionally, each of the transducers 3 can be aligned accordingly on the support body 2.

[0085] Alternatively or additionally, the transducers 3 can be aligned in groups relative to the support body 2. This can be achieved, for example, by the transducer support 5. Accordingly, either the transducer support 5 / each of the transducer supports 5 and / or the support body 2 has alignment means (not shown) suitable for aligning the transducer(s) 3, which emit ultrasound in the direction of the pipeline wall 4, relative to the pipeline wall 4.

[0086] In pulse-echo mode (PE mode), normal probes are used in particular.

[0087] The acoustic transducer system 1 is designed to transmit and / or receive multiple ultrasonic signals in pulse echo mode (PE mode) and in pitch catch mode (PC mode). Electronic transmission and reception parameters, i.e., an excitation signal, a gain factor, and a filter, are selected or adjusted for each mode.

[0088] Pitch catch mode is also called tilt catch mode. In PC mode and PE mode, corrosion detection is performed by analyzing the received ultrasonic waves. In PE mode, transducer 3 emits ultrasound and detects an ultrasonic echo. In PE mode, the same transducers 3 that emit the ultrasound can also detect it.

[0089] In the present exemplary embodiments, the control of the measuring transducers 3 can be a combination of the PE mode and the PC mode. For example, with the combination of PE and PC mode, one measuring transducer 3 can emit ultrasound and one or more other measuring transducers 3 can detect / detect an ultrasonic echo. The measuring transducers 3 can be designed as a single element or as a double element. In a design as a single element, the same surface of the measuring transducer 3 from which the ultrasonic beams emerged, i.e. the exit surface 3a, also receives the ultrasonic echoes. In a double element, the measuring transducer 3 emits ultrasound via an exit surface and receives ultrasonic echoes via an ultrasonic entry surface (not provided with an additional reference symbol) that differs from the exit surface. In the present figures, the reference symbol "3a" is used for the ultrasonic exit surface.In principle, each of the transducers 3 can also have the ultrasonic entry surface where the ultrasonic exit surface 3a is shown in the figures.

[0090] Alternatively or additionally, multiple elements, i.e., multiple single or double elements, in particular multiple single elements, can be provided as the measuring transducer 3. The measuring transducers 3 can be operated at single or double frequency. Operating at double frequency is also referred to as operating with a harmonic.

[0091] The transducers 3 are designed for "Low Frequency Ultrasound Testing" (LFUT). For this purpose, the transducers 3 are designed to generate ultrasound with a central frequency in the range of 300 kHz to 1200 kHz, covering a frequency bandwidth of 100 kHz to 2000 kHz.

[0092] The arrangements of the two exemplary embodiments in Figures 1a and 1b are suitable for detecting defects that have a planar extension in the sound field. Using a pre-transmission path, a transmitted echo can be suppressed, and the measurement is then based on the ultrasound's propagation time between an interface echo and a backwall echo (RF). In the presence of defects in the pipeline whose extension is oriented transversely to the incident sound field, the backwall echo is completely or partially masked, depending on the size of the defect. This allows the extent or size of the defect to be approximately measured, and the depth of the defect in question to be measured based on the propagation time of the ultrasound. Figure 2a schematically shows a structural unit 6 comprising four transducers 3_0, 3_1, 3_2, 3_3. In the present exemplary embodiment, the structural unit 6 also serves as the transducer carrier 5.Alternative embodiments, which are separate parts or in which the structural unit 6 is integrated directly into the carrier body 2, are conceivable.

[0093] During an evaluation, a measurement signal is plotted in a matrix as matrix elements over a time axis and according to the aperture information. In other words, the measurement signals of the individual measuring transducers 3_0, 3_1, 3_2, 3_3 are entered as a matrix element in a matrix according to an arrangement of the measuring transducers 3_0, 3_1, 3_2, 3_3 with respect to the pipeline wall 4. In the present schematic arrangement, four measuring transducers 3_0, 3_1, 3_2, 3_3 are used. Each of the four measuring transducers 3_0, 3_1, 3_2, 3_3 receives ultrasonic echoes. The measuring transducer 3_0 also emits ultrasound. The matrix Mij (t) is then formed with j = 1.. ,N, where N is the number of measuring transducers 3_0, 3_1, 3_2, 3_3. i is then the transmitting element, and j indicates the receiving element. In this example, the matrix Mij has a dimension of 4 x 4.Accordingly, for example, the measurement signal element M02 of the matrix would be an echo signal received at the transducer 3_2, whereby the transducer 3_0 would be the transducer that emits ultrasound.

[0094] A detailed analysis of time domain aperture information of the individual transducers 3_0, 3_1 , 3_2, 3_3, i.e. an analysis of the individual matrices, also called information matrices, shows that the time signals can disappear due to the phase-controlled generation and summation of these signals.

[0095] A complete information matrix Σ Mij is obtained if each transducer 3_0, 3_1, 3_2, 3_3 is an ultrasound emitting element and a matrix Mij is created for each of the transmitting transducers.

[0096] Figure 2b illustrates how, with a plurality of transducers 3_0,...3_N, in which the leftmost transducer 3_0 and the rightmost transducer 3_N each emit ultrasound, they generate an ultrasound wavefront and how this wavefront propagates in the pipeline wall 4 and is detected by the other transducers 3. The transducers 3_0,...3_N are part of a transducer assembly 100. For the sake of simplicity, the reference symbol "3" is shown in Figures 2b and 2c to represent the transducers 3_0,...3_N. The transducers 3_0 and 3_N can also be a single ring-shaped transducer 3, in which case this ring-shaped transducer 3 then encloses the other transducers 3_1,..3_N-1. The other transducers can also be designed as a multitude of rings surrounding one another, similar to the annual rings of a tree trunk.

[0097] Figure 2c illustrates the structure of a sector image and how a defect 7 is detected in a time-resolved measurement signal. The time-resolved measurement signal is also referred to as an A-scan or A-mode. Here, transducer 3_6 is the transducer that emits ultrasound. Transducer 3_4 has the measurement signal that exhibits a deflection that can be used to detect the defect 7. The sector image is indicated in a grid pattern on the pipe wall 4.

[0098] With reference to Figures 3a to 3c, the reference symbols 3A, 3B are assigned to individual transducers 3. The latter reference symbols refer to a structural form of the transducers 3, whereby all transducers 3 can be controlled as first or second transducers 3A, 3B.

[0099] The measuring transducer system 1 comprises at least one structural unit 6. The structural unit 6 of the measuring transducer system 1 comprises a control unit (not shown) and a measuring transducer 3A, 3B. Alternatively, according to an embodiment not shown, a common control unit can be provided for both measuring transducers 3A, 3B / for all measuring transducers. The control unit does not have to be integrated within one of the structural units 6 of the measuring transducer system 1.

[0100] Figures 3a to 3c each show a schematic plan view of an ultrasound entrance / exit surface 3a (reference symbol 3a not shown in Figures 3a to 3c for clarity) of a structural unit 6 of a transducer system 1. In these exemplary embodiments, ultrasound-emitting and ultrasound-detecting transducers 3A, 3B are integrated into the structural unit 6. Depending on the operating mode, the transducers 3A, 3B can operate in PE mode or PC mode as the first transducer 3A or as the second transducer 3B.

[0101] The first transducer 3A is controlled to operate in PE mode, as well as in PC mode. Additionally, the first transducer 3A can be controlled simultaneously in PC mode and PE mode. The second transducer 3B is controlled in PC mode to detect the ultrasonic echo reflected from the pipe wall 4.

[0102] According to the embodiment of Figure 3a, the assembly 6 comprises an emitting transducer 3B and a detecting transducer 3A.

[0103] According to the embodiment of Figure 3b, the assembly 6 comprises a plurality of ultrasonic emitting transducers 3B and an ultrasonic echo detecting transducer 3A arranged centrally to the ultrasonic emitting transducers 3B.

[0104] According to an embodiment of Figure 3c, a structural unit 6 comprises a detecting transducer 3A and an emitting transducer 3B that annularly surrounds the detecting transducer 3A. In other words, the second transducer 3B is formed by a single-member ring at its exit surface 3a, and an entry surface of the first transducer 3A is arranged within the ring.

[0105] Alternatively or additionally, the structural units 6 according to the exemplary embodiment of Figure 3a or 3c are arranged (circularly) in a formation as shown in Figure 3b. The number of detecting transducers 3A arranged in the center and / or emitting transducers 3B arranged in the circle can be adjusted as required, depending on the desired signal-to-noise ratio, the properties of the pipeline, and the size of the transducer system 1. The emitting transducers 3B can also be arranged in several circles of different diameters around the detecting transducer(s) 3A. As an alternative to the aforementioned exemplary embodiments, the detecting transducers 3A are arranged in circles around one or more ultrasonic emitting transducers 3B. This can be implemented either in one structural unit 6 or in several structural units 6 according to the principles described above.

[0106] Figure 4 shows a possible embodiment of the measuring transducer system 1. This embodiment involves a measuring transducer module 100 that is superordinate to the modules 6 and has a plurality of modules 6.

[0107] Based on this arrangement of the transducer system 1, one embodiment of an evaluation method will be explained. In the arrangement shown in Figure 4, a plurality of modules 6 are provided, which transmit / receive ultrasonic signals. The transducers 3 of the respective modules 6 are provided with the reference symbols 3_0, 3_1,...3_N for the purpose of assignment in later explanations. All modules 6 can be arranged on a transducer carrier 5, as shown in Figure 4, or on the carrier body 2. Individual modules 6 can also be arranged on a transducer carrier 5, while others of the modules 6 can be arranged on the carrier body 2.

[0108] A structural unit 6 arranged centrally on the transducer carrier 5 has a transducer with the reference symbol 3_0. The other transducers arranged around the structural unit 6 with the transducer 3_0 are provided with the reference symbols 3_1, 3_2,...3_N. The respective structural units 6 each comprise a disk and a ring arranged around the disk. Both the disk and the ring are transducers 3.

[0109] The evaluation method combines multiple received signals into a data matrix, which serves as input for a tomographic evaluation algorithm of the scanned pipeline. The evaluation of the generated images provides information about the geometry and thickness of the pipeline, as well as the location and sizing of defects within the pipeline. Compared to standard inspection, the tomographic inspection setup leads to improved defect detection, sensitivity, and accuracy.

[0110] For both PE and PC modes, three signals are acquired: backwall echo (RF) signal, which is a high-frequency A-scan signal, FFTI signal, which is a fast Fourier transform of the RF signal, and FFT2 signal, which is a double fast Fourier transform of the RF signal.

[0111] An A-scan signal corresponds to the temporal progression of a received ultrasonic echo generated from an emitted ultrasonic pulse. With periodically generated ultrasonic pulses, a temporal progression, or A-scan, is generated for each ultrasonic pulse.

[0112] In the pulse-echo mode of the measuring transducers 3_0, 3_1, 3_N, the control unit is configured to create six matrices with N columns for each of the measuring transducers 3_0, 3_1, .. ., 3_N, wherein the number N of columns corresponds to the number of measuring transducers 3_0, 3_1,...3_N, wherein each of the columns has at least one entry. A first matrix has travel time measurement values ​​Time_RF as entries, wherein a left column corresponds to the travel time measurement value of a fastest pulse echo, a second matrix contains first-order Fourier transforms of the travel time measurement values, a third matrix contains second-order Fourier transforms of the travel time measurement values, a fourth matrix contains amplitude measurement values, a fifth matrix contains first-order Fourier transforms of the amplitude measurement values, and a sixth matrix contains second-order Fourier transforms of the amplitude measurement values.

[0113] In this case, six matrices are generated in PE mode, for each of the transducers 3_0, 3_1,...3_N:

[0114] In PC measurement, the discs enclosed by the rings are used as transmitters for each assembly 6, and the rings are used as receivers. The electronic transmission and reception parameters are adapted to the PE mode.

[0115] Then, disk 3_0 of the central assembly 6 is used as the transmitter, and all remaining disks 3_1, 3_2,..., 3_N are used as receivers. A similar measurement is performed for all disks 3_0, 3_1, 3_2,..., 3_N up to the last transducer 3_N.

[0116] In this case, the NxN PC measurements are carried out as follows. For each transducer assembly 100, six matrices are filled with measurement data as follows: The control unit of the transducer system 1 evaluates at least one of the matrices. The control unit is connected to the transducers 3 via signal transmission. Ultimately, the integrity of the pipeline wall 4 is determined by evaluating the matrices. This means that a condition can be determined, e.g., the presence of defects or material deposits.

[0117] An echo longitudinal wave or an echo shear wave can be searched for in each of the matrices. In other words, each of the matrices, concerning RF signal and / or FFTI and / or FFT2, can be used for evaluation. The echo longitudinal wave is the wave generated by a material of the pipe wall 4. The echo shear wave is the wave generated by a material that differs from the material of the pipe wall 4. For example, this material can be graphitization of a cast iron pipe wall 4 or a leaching in a cement pipe wall 4. In other words, an evaluation of the matrices also helps in detecting material changes on the pipe wall 4. For example, the method can be used in an ultrasonic inline inspection (ILI) tool for material characterization.

[0118] The control unit is configured to determine the integrity of the pipeline wall 4 based on an occurring change in the ratio between a velocity of the acoustic echo longitudinal wave and a velocity of the acoustic echo shear wave. The control unit is configured to convert the acoustic echo longitudinal wave and the acoustic echo shear wave from a normal ultrasonic pulse echo into modes, and to determine the change in the ratio from the modes of the acoustic echo longitudinal wave and the acoustic echo shear wave.

[0119] The integrity of the pipeline wall 4 is determined by an occurring change in a ratio A between the velocity of the acoustic echo longitudinal wave and the velocity of the acoustic echo shear wave, which is defined as follows:

[0120] A=cl / ct=Tt / Tl where cl is the velocity of the acoustic echo longitudinal wave, ct is the velocity of the acoustic echo shear wave, TI is an arrival time of a mode of the acoustic echo longitudinal wave and Tt is an arrival time of a mode of the acoustic echo shear wave.

[0121] The transducer system 1 in this case has a plurality of transducers 3_0, 3_1, . . ,,3_N. The control unit is configured to represent the change in the ratio between the velocity of the acoustic echo longitudinal wave and the velocity of the acoustic echo shear wave for each of the transducers 3_0, 3_1, . . ., 3_N as a matrix element of a matrix, wherein one dimension of a matrix row corresponds to a number N of the transducers 3_0, 3_1, . . ., 3_N minus 1.

[0122] Figures 5 and 6 show simulations of determining an acoustic velocity ratio A. In the simulation of Figure 5, a 5 MHz echo pulse was assumed with a pipe wall thickness of 20 mm and a s0 of 40 mm. In the simulation of Figure 6, a 0.6 MHz echo chirp was assumed with a pipe wall thickness of 20 mm and a s0 of 40 mm. In the graph at the top left in both Figures 5 and 6, a temporal progression of the amplitude is plotted (RF S1). In the graph at the top right in both Figures 5 and 6, a first-degree Fourier transform of the temporal progression of the amplitude is plotted (Processed S2). In the graph at the bottom left, in both Figures 5 and 6, a second-order Fourier transform of the temporal variation of the amplitude is recorded (Processed S3).In the graph at the bottom right, both Figures 5 and 6 show a third-order Fourier transform of the temporal variation of the amplitude (processed S4). Both simulations in Figures 5 and 6 result in a velocity ratio A of 1.8. List of reference symbols.

[0123] 1 acoustic transducer system

[0124] 2 carrier bodies

[0125] 3 measuring transformers

[0126] 3a Exit surface of the transducer

[0127] 3A first measuring transformer

[0128] 3B second measuring transformer

[0129] 3 0, 3_1, ...3_N

[0130] instrument transformer

[0131] 4 Pipe wall

[0132] 4a Inner surface of the pipeline wall

[0133] 5 transducer carriers

[0134] 6 Unit

[0135] 7 defects

[0136] 100 instrument transformer assembly

[0137] G3a Surface normal of the exit surface

[0138] N4a Surface normal of the pipeline wall

Claims

Patent claims 1. An acoustic transducer system (1) for determining the integrity of a pipeline wall (4) made of carbon steel, stainless steel, cast iron, or cement, comprising: at least one transducer (3, 3_0, 3_1,..., 3_N) configured to emit an acoustic wave toward the pipeline wall (4) and to detect an acoustic echo longitudinal wave generated by the pipeline wall (4) and an acoustic echo shear wave generated by the pipeline wall (4); and a control unit signal-connected to the transducer (3, 3_0, 3_1,..., 3_N), which control unit is configured to determine the integrity of the pipeline wall (4) based on an occurring change in a ratio between a velocity of the acoustic echo longitudinal wave and a velocity of the acoustic echo shear wave.

2. Acoustic transducer system according to claim 1, comprising: at least two transducers (3, 3_0, 3_1,..., 3_N), each configured to emit an acoustic wave in the direction of the pipeline wall (4) and to detect an acoustic echo longitudinal wave generated by the pipeline wall (4) and an acoustic echo shear wave generated by the pipeline wall (4); and a control unit signal-connected to each of the transducers (3, 3_0, 3_1,..., 3_N), which control unit is configured to determine the integrity of the pipeline wall (4) based on an occurring change in a ratio between a velocity of the acoustic echo longitudinal wave and a velocity of the acoustic echo shear wave.

3. The acoustic transducer system according to claim 1 or 2, wherein the control unit is configured to convert the acoustic echo longitudinal wave and the acoustic echo shear wave from a normal ultrasonic pulse echo into modes, respectively, and to determine the change in the ratio from the modes of the acoustic echo longitudinal wave and the acoustic echo shear wave.

4. Acoustic transducer system according to one of claims 1 to 3, wherein the control unit is configured to determine the integrity of the pipeline wall (4) based on an occurring change in the ratio A between the velocity of the acoustic echo longitudinal wave and the velocity of the acoustic echo shear wave, which is defined as follows: where cl is the velocity of the acoustic echo longitudinal wave, ct is the velocity of the acoustic echo shear wave, TI is an arrival time of the acoustic echo longitudinal wave, Tt is an arrival time of the acoustic echo shear wave.

5. Acoustic transducer system according to at least one of claims 1 to 4, comprising a plurality of transducers (3_0, 3_1,...,3_N), wherein the control unit is configured to represent the change in the ratio between the velocity of the acoustic echo longitudinal wave and the velocity of the acoustic echo shear wave for each of the transducers (3_0, 3_1,...,3_N) as a matrix element of a matrix, wherein a dimension of a matrix row corresponds to a number N of the transducers (3_0, 3_1,...,3_N) minus 1.

6. Acoustic transducer system according to at least one of claims 1 to 5, comprising a plurality of transducers (3_0, 3_1,...,3_N), wherein in a pulse-echo mode of the transducers (3_0, 3_1,...,3_N) the control unit is configured to create six matrices with N columns for each of the transducers, wherein the number N of columns corresponds to the number of transducers, wherein each of the columns has at least one entry, wherein - a first matrix has as entries runtime measured values ​​Time_RF, with the runtime measured value of a fastest pulse echo corresponding to a left column, - a second matrix comprises first-order Fourier transforms of the transit time measurements, - a third matrix Fourier transforms of second degree of the runtime- measured values, - a fourth matrix has amplitude measurements, - a fifth matrix of first-order Fourier transforms of the amplitude measured values, and - a sixth matrix of second-order Fourier transforms of the amplitude measured values.

7. Acoustic transducer system according to at least one of claims 1 to 6, comprising: - at least two measuring transducers (3), a carrier body (2) and at least one measuring transducer carrier (5), wherein the at least two measuring transducers (3) are connected to the measuring transducer carrier (5), wherein the at least one measuring transducer carrier (5) is designed to be pivotable and / or movable away from the carrier body (2) and / or towards the carrier body (2).

8. Acoustic transducer system according to at least one of claims 1 to 6, comprising at least one transducer assembly (100), wherein the transducer assembly (100) has a plurality of transducers (3_0, 3_1,.. .,3_N), wherein the transducers (3_0, 3_1,. ..,3_N) are arranged in at least one circle, wherein at least one further transducer (3_0, 3_1, .. .,3_N) is arranged in a circle center.

9. Computer-implemented method of an acoustic transducer system (1) for determining the integrity of a pipeline wall (4) made of carbon steel, stainless steel, cast iron or cement, the method comprising: Emitting, by means of at least one measuring transducer (3, 3_0, 3_1,...,3_N), an acoustic wave in the direction of the pipe wall (4) and Detecting, by means of the at least one transducer (3, 3_0, 3_1,..., 3_N), an acoustic echo longitudinal wave generated by the pipe wall (4) and an acoustic echo shear wave generated by the pipe wall (4); and Determining, by means of a control unit connected to the measuring transducer (3, 3_0, 3_1,. . ,,3_N) by signal technology, the integrity of the pipeline wall (4) on the basis of an occurring change in a ratio between a speed the acoustic echo longitudinal wave and a velocity of the acoustic echo shear wave.

Images