Calibration method for a flow measurement system, flow measurement system and computer program product

Abstract

The invention relates to a method (100) for calibrating a flow measurement system (30) installed on a pipeline (12) containing a medium (11). The method (100) comprises a first step (110) in which the flow measurement system (30) is prepared in an active operating state. The flow measurement system (30) comprises a first flow sensor (10). The method (100) also comprises emitting an ultrasonic pulse (25) to the pipeline wall (13) by means of a first ultrasonic head (22) or a second ultrasonic head (24) of the first flow sensor (10). In a second step (120), an ultrasonic echo (29) is also received by means of the second ultrasonic head (24). The method (100) also comprises a third step (130) in which the signal propagation times of the ultrasonic pulse (25) and the ultrasonic echo (29) are determined. Based on this, the pipeline wall thickness (19) is determined. Furthermore, in a fourth step (140), at least one calibration parameter of the first flow sensor (30) is set. The at least one calibration parameter comprises at least the pipe wall thickness (19). The present invention also relates to a flow measurement system (30) suitable for carrying out such a method (100). Furthermore, the present invention relates to a computer program product (50) designed to simulate the operating behavior of such a flow measurement system (30). Likewise, the present invention relates to the use of a flow measurement system (30) for carrying out an adjustable and simultaneous recalibration during a measuring operation.

Description

Technical Field

[0001] The present invention relates to a calibration method for a flow measurement system. The present invention also relates to a flow measurement system suitable for carrying out such a calibration method. Furthermore, the present invention relates to a computer program product for simulating the operating behavior of a corresponding flow measurement system. Background Art

[0002] Patent application DE 10 2009 002 942 A1 discloses a method for determining the pipe wall thickness in a Coriolis flowmeter, i.e., the pipe wall thickness of a measuring pipe. The measuring pipe is a mechanical oscillating system that can be excited into oscillation by an exciter. The pipe wall thickness is determined using detected excitation input values and response values of the oscillating system, which are used in a transfer equation.

[0003] Patent application DE 10 2015 107 752 A1 discloses a method for determining the pipe wall resonant frequency of a pipeline line in the region of a measurement location. The method includes transmitting an ultrasonic signal and detecting the received signal. The pipe wall resonant frequency is determined based on a transfer function at the measurement location. Based on this, the pipe wall thickness and / or pipe wall material can be determined.

[0004] Patent application DE 10 2007 019 689 A1 discloses a device for determining the volume flow of a medium, comprising two ultrasonic sensors arranged along a pipe axis, which can emit ultrasonic pulses diagonally into the pipe to measure the volume flow. At least one of the ultrasonic sensors has a piezoelectric element, which serves as a diagnostic sensor and is configured to emit ultrasonic pulses perpendicular to the pipe axis into the pipe to determine diagnostic data.

[0005] Publication US2020 / 0326216 A1 discloses an ultrasonic flowmeter with multiple piezoelectric transducers. The first and second piezoelectric transducers are configured to transmit ultrasonic pulses at an angle into a pipe to which the ultrasonic flowmeter is mounted. A third piezoelectric transducer is positioned between the first and second transducers and is configured to transmit and receive ultrasonic pulses perpendicular to the pipe axis. This allows the inner diameter of the pipe to be determined.

[0006] US 2017 / 0153136 A1 discloses a flow meter that can be clamped onto a pipe and includes an automatic function for determining pipe wall thickness. To do this, a resonant frequency is excited and recorded while scanning the spectrum. The wall thickness is determined based on this frequency, along with information about the pipe's outer diameter and the material of the pipe wall.

[0007] Flow measuring instruments are used in many applications, such as process plants, to measure flow rates or throughput in pipelines. Increasing demands are placed on measurement accuracy, durability, and ease of assembly. The present invention is based on the object of providing a flow measuring system and an associated calibration method that offer improvements in at least one of the aforementioned aspects. Summary of the Invention

[0008] The object is achieved by a method according to the present invention for calibrating a flow measurement system. The flow measurement system is mounted on a pipeline containing a medium in its inner diameter, and the flow rate and thus the flow velocity of the medium are measured. For example, the medium can be a gas, a liquid, a suspension, a foam, or a slurry. The method comprises a first step in which the flow measurement system is prepared in an active operating state and adapted for non-diffusion flow measurement. The flow measurement system comprises a first flow sensor mounted on the pipeline. In the active state, the first flow sensor is adapted to transmit ultrasonic pulses through the pipeline wall into the inner diameter of the pipeline.

[0009] The method also includes a second step, in which an ultrasonic pulse is emitted into the pipe wall using a first ultrasonic head or a second ultrasonic head. The ultrasonic pulse can be directly directed into the pipe wall in the region of the ultrasonic head. The first ultrasonic head and the second ultrasonic head belong to and are associated with a first flow sensor. The emitted ultrasonic pulse traverses the pipe wall and is reflected from the inside of the pipe wall. The ultrasonic pulse reflected in the second step is received as an ultrasonic echo by the second ultrasonic head. Therefore, there is a signal propagation time between the emission of the ultrasonic pulse and the reception of the ultrasonic echo, during which the pipe wall is traversed twice. The method also includes a third step, in which the signal propagation time of the ultrasonic pulse or the ultrasonic echo is determined. In this third step, the pipe wall thickness is determined based on the signal propagation time. At least one alignment angle between the pipe axis and the main propagation direction of the ultrasonic pulse is taken into account. This creates a calculable correlation between the signal propagation time and the pipe wall thickness. Additionally, in the third step, the pipe inner diameter can be determined using the pipe wall thickness and information about the pipe outer diameter. Such information can be provided, for example, by user input.

[0010] The method also includes a fourth step, in which at least one calibration parameter of the first flow sensor is adjusted. The at least one calibration parameter includes the pipe wall thickness and / or pipe inner diameter determined in the third step. The ultrasonic head provides an improved criterion for measurement accuracy, enabling the pipe wall thickness to be determined with increased accuracy using the method according to the present invention. The method can be performed automatically, which allows for rapid recalibration of the flow measurement system during operation. In particular, the flow measurement system can adapt to changes in pipe wall thickness, and thus, changes in pipe inner diameter. Pipe wall thickness can decrease due to corrosion of the pipe wall or increase due to contamination. Furthermore, pipe walls are manufactured with reduced accuracy, often making the exact pipe wall thickness unknown. The method according to the present invention can compensate for these effects on the measurement accuracy of the flow measurement system. Adjustment of the at least one calibration parameter is achieved, for example, by storing the corresponding value in an evaluation unit of the flow measurement system.

[0011] According to the present invention, in the second step of the method, an ultrasonic pulse is emitted diagonally from the pipeline axis into the medium and, thereby, into the pipeline wall. Furthermore, a second ultrasonic head and an ultrasonic reflector are arranged relative to the first ultrasonic head so that the main propagation directions of the ultrasonic pulse and the flow measurement pulse do not intersect. The ultrasonic reflector allows for simple measurement while simultaneously performing the claimed method. The emission of ultrasonic pulses into the medium and, thereby, into the pipeline wall, according to the present invention, allows for the determination of the surface roughness of the inner surface of the pipeline wall in a diagonal direction. To this end, the intensity of the ultrasonic echo received in the second step is measured and compared with the intensity of the emitted ultrasonic pulse. The rougher the inner surface of the pipeline wall, the stronger the reflection back to the second ultrasonic head. The smaller the relationship between the intensity of the emitted ultrasonic echo and the intensity of the emitted ultrasonic pulse, for example, the smaller the surface roughness of the inner surface of the pipeline wall. Based on this, the surface roughness of the inner surface of the pipeline wall can be determined. For this purpose, numerical tables and / or information on the material of the pipeline wall are considered. This allows, in particular, precise determination of the medium throughput in a pipeline using the Hagen-Poisson equation. In the fourth step according to the invention, the determined surface roughness of the inner side of the pipeline wall is adjusted as a calibration parameter. This further improves the accuracy achieved by calibration using the claimed method. Furthermore, a further analysis is performed to determine the pipeline wall thickness and surface roughness.

[0012] In an embodiment of the claimed method, an ultrasonic reflector is associated with the second ultrasonic head of the first flow sensor. This ultrasonic reflector is suitable for deflecting the ultrasonic pulse emitted in the second step. The pipe wall thickness is determined using the ultrasonic pulse; by deflecting the ultrasonic pulse, the ultrasonic pulse can be displaced from the flow measurement pulse. This prevents spatial superposition of the ultrasonic pulse with the flow measurement pulse. This allows for simultaneous measurement and execution of the claimed method. Furthermore, the ultrasonic reflector has dimensions corresponding to a multiple of the wavelength of the ultrasonic pulse. Furthermore, the ultrasonic reflector easily directs the ultrasonic pulse in a direction favorable for determining the pipe wall thickness.

[0013] In another embodiment of the claimed method, the first ultrasonic head is designed to emit flow measurement pulses. Therefore, the first ultrasonic head can be operated independently of the second ultrasonic head. Consequently, the first and second ultrasonic heads can be optimally designed for their respective purposes. This allows for simple and cost-effective use of the ultrasonic heads for the first and second ultrasonic heads. Alternatively or additionally, the first and second ultrasonic heads can also be designed as an integrated combined ultrasonic head. In particular, the first and second ultrasonic heads can be designed as independently controllable sections of a combined ultrasonic head. Furthermore, the first and second ultrasonic heads use a common piezoelectric element, which can be controlled in sections via independent electrodes. Such a combined ultrasonic head is compact and therefore offers space-saving possibilities. If only the first flow sensor is designed to perform the claimed method, it is sufficient in the flow measurement system. Corresponding adaptation of the second flow sensor is unnecessary. Overall, the claimed method adapts to different requirements in terms of compactness and cost-effectiveness.

[0014] Furthermore, the ultrasonic pulses emitted in the second step can be distinguished from the flow measurement pulses by an electronic filter, in particular a bandpass filter. The electronic filter is designed in an evaluation unit in the flow measurement system. This allows the claimed method for measuring operations to be performed simultaneously. Superposition between the flow measurement pulses and the ultrasonic pulses or the ultrasonic echoes of the ultrasonic pulses can be tolerated. This avoids the need for time-slicing coordination of the first and second ultrasonic heads. For example, the flow measurement pulses and the ultrasonic pulses may have different frequencies or distinguishable pulse patterns. The electronic filter can be designed using electronic components and / or algorithms in the flow measurement system.

[0015] Alternatively or in addition, the ultrasonic pulses and the flow measurement pulses are designed to be distinguishable by means of time-delayed emission. In this case, the first ultrasonic head and the second ultrasonic head are operated in a time-slicing operation. Since the pipe wall thickness is smaller than the pipe inner diameter, the signal propagation time of the ultrasonic pulse is shorter than the signal propagation time of the flow measurement pulse, the pipe wall thickness is determined with the aid of the ultrasonic pulse, and the flow velocity of the medium is measured using the flow measurement pulse. The first time slice for measuring the pipe wall thickness can be designed to be shorter than the second time slice, wherein the flow velocity of the medium, i.e. the amount of the medium passing through, is measured with the aid of the flow measurement pulse. As a result, the measuring operation, in which the flow velocity of the medium is measured, is only minimally negatively affected by the claimed method. In addition, the claimed method allows for a compact structural type of the first flow sensor, in which the main propagation directions of the ultrasonic pulses and the flow measurement pulses intersect.

[0016] Furthermore, the ultrasonic pulse emitted in the second step has a bandwidth of 25 kHz to 8 MHz, preferably 40 kHz to 6 MHz, and more preferably 50 kHz to 4 MHz. Alternatively or additionally, the ultrasonic pulse has a pulse duration of 0.1 μs to 5.0 ms, preferably 0.15 μs to 3 ms, and particularly preferably 0.25 μs to 1.0 ms. Furthermore, the present invention is based on the surprising realization that correspondingly broadband and short ultrasonic pulses also produce ultrasonic echoes in the second step that enable precise determination of the pipe wall thickness. In particular, with such ultrasonic pulses, sufficient ultrasonic echoes are reflected diagonally during emission to allow determination of the pipe wall thickness.

[0017] In another embodiment of the claimed method, the third step is performed while taking into account information about the material of the pipeline wall. The material of the pipeline wall substantially determines the speed of sound in the pipeline wall. This information about the material of the pipeline wall can be provided directly via user input and / or via information about the construction type of the pipeline, which can be stored, for example, in the evaluation unit. Alternatively or additionally, information about the attachment of the first flow sensor to the pipeline can also be taken into account. Depending on the attachment of the first flow sensor to the pipeline, for example, the expected intensity of the ultrasonic echo is predetermined.

[0018] Furthermore, the claimed method can also use the pipeline wall thickness determined in the third step to determine current pipeline corrosion or contamination. In particular, the extent of the corrosion or contamination can be determined. To this end, the pipeline wall thickness determined in the third step is compared with historical values of the pipeline wall thickness. In particular, a difference can be determined between the pipeline wall thickness determined in the third step and at least one historical value of the pipeline wall thickness. If the difference exceeds an adjustable threshold, a warning can be issued to the user. This allows necessary maintenance procedures to be identified early, thereby reducing downtime of the process plant during the execution of the claimed method.

[0019] The basic object is also achieved by an evaluation unit according to the invention, which can be used in a flow measurement system having at least one first flow sensor. The evaluation unit is suitable for receiving and evaluating the measurement signal of the first flow sensor. In addition, the evaluation unit is designed to output a determined flow rate of a medium in a pipeline on which the flow system can be installed. According to the invention, the evaluation unit is designed for this purpose to be calibrated with the aid of at least one embodiment of the above-mentioned method. Accordingly, the characteristics of the method and / or the flow measurement system described below can be transferred to the evaluation unit. The evaluation unit can be designed as a local evaluation unit, which is accommodated in one of the flow sensors. Alternatively, the evaluation unit can also be designed as an industrial controller, for example a so-called PLC controller, a main computer, a computer cloud or a combination thereof.

[0020] The stated object is also solved by the flow measurement system according to the invention. The flow measurement system comprises a first flow sensor and a second flow sensor, which can be mounted on a pipeline in order to measure the flow of a medium in the pipeline in a non-invasive manner. The first flow meter comprises a first ultrasonic head for emitting a flow measurement pulse. The second flow sensor is designed to receive an echo of the flow measurement pulse. The first flow sensor and the second flow sensor act together to determine the flow of the medium in the pipeline, for example via an evaluation unit. According to the invention, the first flow sensor is provided with a second ultrasonic head, which is designed to determine the inner diameter of the pipeline. For example, the second ultrasonic head can be designed to perform at least one embodiment of the above-described method. Therefore, the characteristics described in the present method are directly transferred to the flow measurement system according to the invention. According to the invention, the flow measurement system has an evaluation unit according to one of the above-described embodiments.

[0021] Furthermore, the second ultrasonic head is designed to transmit ultrasonic pulses and / or receive ultrasonic echoes. The ultrasonic pulses are introduced directly into the pipe wall via the second ultrasonic head. The ultrasonic pulses are reflected as ultrasonic echoes in opposing areas on the inside of the pipe wall and can be received by the second ultrasonic head. The second ultrasonic head can be designed to transmit the ultrasonic pulses diagonally or substantially radially relative to the pipe axis.

[0022] In one embodiment of the claimed flow measurement system, the first flow sensor includes at least one ultrasonic reflector designed to deflect ultrasonic pulses emitted by the first ultrasonic head and / or the second ultrasonic head. The ultrasonic reflector can be arranged so that the ultrasonic pulses are emitted substantially radially into the pipe wall. This ensures that the ultrasonic pulses are effectively reflected as ultrasonic echoes from opposing areas on the inside of the pipe wall back to the second ultrasonic head. This clear ultrasonic echo further allows for a precise determination of the pipe inner diameter.

[0023] In addition, the ultrasonic reflector is designed as a partially transparent or controllable ultrasonic reflector. With the help of the partially transparent ultrasonic reflector, only the ultrasonic pulse or ultrasonic echo can be deflected, but not the flow measurement pulse. In other words, the flow measurement pulse passes through the partially transparent ultrasonic reflector. As a result, the ultrasonic reflector has improved specifications and can be manufactured in a simple and cost-effective manner. Alternatively, the controllable ultrasonic reflector is turned on and off under the deflection of the ultrasonic reflector. For example, such a time-slicing operation is switchable, in which the first ultrasonic head and the second ultrasonic head are positioned close to each other and emit in essentially the same direction. With the help of this reflector, different variants of the above-mentioned method are reliably converted. The claimed flow measurement system also allows multiple embodiments of the claimed method to be converted in a cost-effective manner. As a result, the claimed flow measurement system is simply applicable to multiple use cases.

[0024] Furthermore, the object described at the outset is achieved by a computer program product according to the invention. The computer program product is designed to simulate the operating behavior of a flow measurement system. The computer program product can include commands that cause a computer to simulate the operating behavior of a flow measurement system.

[0025] In particular, a computer program product can be configured to simulate the operating behavior of a flow measurement system, wherein the structure of the flow measurement system is fixedly predetermined in the computer program product, i.e., a model of the flow measurement system is stored. Alternatively, the operating behavior can be represented by an abstract computational model that is independent of the spatial structure of the flow measurement system. Furthermore, the operating behavior can be determined by combining these. According to the present invention, a flow measurement system for simulation is designed according to one of the above-described embodiments. For the simulation, the computer program product can include a physical module in which the flow measurement system is mapped and, for example, its ultrasonic-acoustic or signal-technical behavior can be adjusted under adjustable operating conditions. For example, adjustable operating conditions include the temperature of the medium in the pipeline, the current sound velocity in the medium, the viscosity of the medium, the flow velocity of the medium, the pressure of the medium, and the flow behavior, particularly turbulent behavior or flow velocity profile. To this end, the computer program product includes a data interface, which can be predefined with corresponding data for user input and / or other simulation instructions for the computer program product. The computer program product can also include a data interface for transmitting simulation results to the user and / or other simulation instructions for the computer program product. For example, a computer program product can be used to check the plausibility of signal propagation data detected by an ultrasonic head or other sensor values of the device, and a flow measurement system can be used in the device. Furthermore, this can identify damaged components in the flow measurement system, such as a damaged ultrasonic head. In particular, it can be determined whether the inner surface roughness of the pipe wall, certain corrosion or contamination, is plausible after a known operating time, or whether a damaged component in the flow measurement system is expected. Furthermore, the present invention is based on the surprising realization that the above-described method can model, for example, the reflection behavior of the pipe wall relative to a first flow sensor with improved accuracy while using relatively little computational effort. Accordingly, the computer program product according to the present invention provides extensive and computationally efficient options for monitoring and / or testing corresponding flow measurement systems. The computer program product can be designed as a so-called digital twin, as described in more detail, for example, in patent application 2017 / 286572 A1. The disclosure of 2017 / 286572 A1 is incorporated herein by reference. The computer program product can be designed as a monolithic system, i.e., fully executable on a single hardware platform. Alternatively, the computer program product can be designed in a modular manner and include multiple subroutines that can be executed on separate hardware platforms and interact via a communication data connection. In particular, the computer program product can be designed for execution in a computer cloud. Furthermore, the computer program product according to the present invention can be used to test and / or optimize flow measurement systems via simulations, for example, in the case of planned modifications in process plants.

[0026] In addition, the objectives described at the outset are achieved by using a flow measurement system according to the present invention. The flow measurement system is fixed to a pipeline through which a medium flows for performing a measurement operation. The flow velocity of the medium and, thereby, the amount of the medium passing through are measured by the measurement operation. According to the present invention, the flow measurement system, which includes at least one first flow sensor, is also used to determine the pipe wall thickness of the pipeline during the measurement operation. In addition, the measurement accuracy of the measurement operation is influenced by the pipe wall thickness, which is stored as a calibration parameter in an evaluation unit of the flow measurement system. Accordingly, the flow measurement system is used for adjustable simultaneous recalibration during the measurement operation. Simultaneous recalibration is understood here to mean determining the pipe wall thickness during the measurement operation. In particular, the recalibration by determining the pipe wall thickness as a calibration parameter is performed at intervals and is adjustable by the user. To this end, a flow measurement system is designed according to at least one of the above-mentioned embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is described in more detail below with reference to various embodiments in the accompanying drawings. Where the same reference symbols in different figures have the same technical meaning, these figures are intended to complement each other to a certain extent. Features of the various embodiments can be combined with one another. Furthermore, the embodiments shown in the drawings can be combined with the features described above. In detail, the following are shown:

[0028] Figure 1 A longitudinal section and a cross section showing an exemplary structure of the claimed flow measurement system;

[0029] Figure 2 A longitudinal section showing a detailed view of a first flow sensor in a second embodiment of the claimed flow measurement system;

[0030] Figure 3 A longitudinal section showing a detailed view of a first flow sensor in a third embodiment of the claimed flow measuring system;

[0031] Figure 4 A longitudinal section showing a detailed view of a first flow sensor in a fourth embodiment of the claimed flow measurement system;

[0032] Figure 5 A longitudinal section showing a detailed view of a first flow sensor in a fifth embodiment of the claimed flow measuring system;

[0033] Figure 6 A longitudinal section shows a view for determining the surface roughness in the claimed method. DETAILED DESCRIPTION

[0034] exist Figure 1, the structure of the claimed flow measurement system 30 is shown by way of example in a longitudinal section. The flow measurement system 30 is here in a stage of the claimed method 100 for calibrating the flow measurement system 30. The flow measurement system 30 comprises a first flow sensor 10 and a second flow sensor 20, which are mounted on a pipeline 12. The first flow sensor 10 and the second flow sensor 20 are coupled to an evaluation unit 40, which is also part of the flow measurement system 40. The flow measurement system 30 is in an active state, i.e., in an operational state, such that Figure 1 The first step 110 of the method 100 as claimed in the present invention is completed. The pipeline 12 has a pipeline wall 13, which surrounds a medium 11 and the medium flows through the pipeline 12 along the pipeline axis 15. The medium 11 has a temperature 14 and a flow velocity 16. During the measurement operation of the flow measurement system 30, the flow velocity 16 of the medium 11 is determined, so that the flow rate of the medium 11 can be calculated based on this. The pipeline wall 13 has a pipeline wall thickness 19 and a pipeline inner diameter 21, and the pipeline wall thickness 19 is determined by the pipeline wall, as shown in FIG. Figure 1 Shown in the cross-sectional view on the right. Figure 1 The diagram shows a measuring operation in which a flow pulse 35 is sent into the medium 11 by the first ultrasonic head 22 in the first flow sensor 10. An echo 37 of the flow measurement pulse 35 is reflected onto the pipe wall 18 opposite the first flow sensor 10 and the second flow sensor 20. The echo 37 is received by the further ultrasonic head 26, which is arranged on the second flow sensor 20. Signal propagation times are derived for the flow measurement pulse 35 and the echo 37 of the flow measurement pulse, which are evaluated in order to determine the flow velocity 16. For this purpose, a measurement signal 45 is transmitted from the first flow sensor 10 and the second flow sensor 20 to an evaluation unit 40. Figure 1 In the stage shown in FIG, flow measurement system 30 is ready to carry out the further steps of method 100, as described below. In addition, the operating behavior of flow measurement system 30 is simulated by a computer program product 50 (not shown in detail), which is designed as a digital twin of at least first flow sensor 10.

[0035] According to a first embodiment of the claimed flow measurement system 30, a detailed longitudinal section of the first flow sensor 10 is shown in FIG. Figure 2 The first flow sensor 10 includes a first ultrasonic head 22, which is suitable for transmitting flow measurement pulses 35 (not shown). The first flow sensor 10 (as shown in FIG. Figure 1 ) is mounted on the pipe 12, i.e. on the pipe wall 13 of the pipe and is in an active operating state. Figure 2, the first step 110 of the method 100 has been completed. The first ultrasonic head 22 is also designed to emit an ultrasonic pulse 25 in the second step 120 of the method 100, with the aid of which the pipe wall thickness 19 is determined. The ultrasonic pulse 25 propagates along the main propagation direction 36, which is in the direction of the pipe wall thickness 19. Figure 2 The direction of the arrow is shown in FIG. The ultrasonic pulse 25 is deflected at the pipe wall 13 and enters the pipe wall 13 diagonally relative to the pipe axis 15 . Furthermore, the ultrasonic pulse 25 is reflected as an ultrasonic echo 29 in the opposite region of the inner side 17 of the pipe wall 18 . The ultrasonic echo 29 is also deflected upon exiting the pipe wall 13 . The ultrasonic echo 29 is received by the second ultrasonic head 24 , which is arranged in the first flow sensor 10 . Based on the measurement signals 45 of the first ultrasonic head 22 and the second ultrasonic head 24 , the pipe wall thickness 19 is determined in the evaluation unit 40 . To this end, the signal propagation time of the ultrasonic pulse 25 and the ultrasonic echo 29 of the ultrasonic pulse is determined using the measurement signal 45 . Based on information about the temperature 14 of the medium 11 and the material of the pipe wall 13 , the speed of sound in the pipe wall 13 can be determined. Based on this, the pipe wall thickness 19 can be determined in a third step 130 based on the signal propagation time of the ultrasonic pulse 25 and the ultrasonic echo 29 of the ultrasonic pulse from the first ultrasonic head 22 to the second ultrasonic head 24 . In addition, the pipe inner diameter 21 can also be determined in a third step 130, taking into account the pipe outer diameter 23. Here, the deflection behavior of the ultrasonic pulse 25 and / or the ultrasonic echo 29 when entering or exiting the pipe wall 13 is also taken into account. In a fourth step 140, the determined pipe wall thickness 19 and / or pipe inner diameter 21 are stored as calibration parameters in the evaluation unit 40. Calibration parameters such as the pipe wall thickness 19 and / or pipe inner diameter 21 can be used in measurement operations, for example Figure 1 As shown, to determine the flow rate of the medium 11, that is, to basically determine the flow velocity 16 of the medium. Figure 2 The method 100 for calibration shown in FIG. 1 can be integrated in a simple manner into a system such as Figure 1 During measurement operation, for example, in time-slice mode, changes in pipe wall thickness 19 and, therefore, changes in pipe inner diameter 21, can be determined by comparison with historical values 42 for pipe wall thickness. For this purpose, the corresponding historical values 42 for pipe wall thickness 19 or pipe inner diameter 21 are stored in evaluation unit 40. Thus, an increase in pipe inner diameter 21 indicates corrosion of inner side 17 of pipe wall 13. Conversely, a decrease in pipe inner diameter 21 indicates contamination of pipe 12, resulting in a narrowing of pipe 12. This state can be displayed to the user via evaluation unit 40.

[0036] In addition, according to Figure 2In an embodiment, the surface roughness 27 on the inner side 17 of the pipe wall 13 is determined. An ultrasonic pulse 25 is transmitted from the first ultrasonic head 22 to the pipe wall 13. Due to the surface roughness 27 on the inner side 17 of the pipe wall 13, a portion of the ultrasonic pulse 25 is reflected back to the first ultrasonic head 25 as an ultrasonic echo 29. The ultrasonic echo 29 received by the first ultrasonic head 22 has a reduced intensity compared to the transmitted ultrasonic pulse 25. The ultrasonic pulse 25 is dispersed by the surface roughness 27, so that the ultrasonic echo 29 received by the second ultrasonic head 24 has a reduced intensity compared to the transmitted ultrasonic pulse 25. The intensity of the ultrasonic echo 29 is detected and transmitted as a test signal 45 to an evaluation unit 40. The ultrasonic echo is received by the first ultrasonic head 22 or the second ultrasonic head 24. The evaluation unit then determines the surface roughness 27 of the inner side 17 of the pipe wall 13. The operating behavior of the first flow sensor 10 can be simulated via a computer program product 50 (not shown), which is designed as a digital twin of at least the first flow sensor 10 .

[0037] exist Figure 3 , a longitudinal section is shown in FIG. 1 , by way of example, in a second embodiment of the claimed flow measurement system 30 , as a first flow sensor 10 . Figure 3 It is assumed that the first step 110 of the claimed method 100 has been completed, wherein the flow measurement system 30 is set in an active operating state. The first flow sensor 10 has a first ultrasonic head 22, which is aligned essentially diagonally with respect to the pipe axis 15 of the pipe 12. The first ultrasonic head 22 is arranged in the first flow sensor 10 in such a way that a flow measurement pulse 35 is directed diagonally into the pipe wall 13. Upon entering the pipe wall 13, the flow measurement pulse 35 is deflected. The flow measurement pulse 35 is part of the measuring operation of the flow measurement system 30. For the flow measurement pulse 35, a measurement signal 45 is sent to the evaluation unit 40. Furthermore, the first flow sensor 10 has a second ultrasonic head 24, which is arranged spaced apart from the first ultrasonic head 22 in the axial direction, i.e. along the pipe axis 15. The second ultrasonic head 24 is located between the first ultrasonic head 22 and Figure 3The second ultrasonic head 24 is designed to transmit the ultrasonic pulse 25 essentially in the radial direction 33 into the pipe wall 13. This is achieved in the second step 120 of the claimed method 100. The ultrasonic pulse 25 passes through the medium 11 and is reflected as an ultrasonic echo 29 in the opposite region of the inner side 17 of the pipe wall 13. The second ultrasonic head 24 is designed to also receive the ultrasonic echo 29 in the second step 120. The deflection of the ultrasonic pulse 25 when entering the pipe wall 13 and when exiting the pipe wall 13 is minimal and Figure 3 The ultrasonic pulse 25 and the ultrasonic echo 29 have opposite main propagation directions 36, which are Figure 3 , indicated by arrows. The second ultrasonic head 24 is suitable for interacting with the evaluation unit 40 to measure the signal propagation times of the ultrasonic pulse 25 and the ultrasonic echo 29. For this purpose, the corresponding measurement signal 45 is transmitted to the evaluation unit 40. The evaluation unit 40 is also designed to take into account the temperature 14 of the medium 11 and information about the material of the medium 11 to determine the current sound velocity in the medium 11. Based on this, at least the pipe wall thickness 19 can be determined in a third step 130 from the signal propagation times of the ultrasonic pulse 25 and the ultrasonic echo 29 and the installation position of the second ultrasonic sensor 24. On this basis, the pipe inner diameter 19 can also be determined in the third step 130. This is achieved through calculations in the evaluation unit 40. The determined pipe wall thickness 19 is stored as a calibration parameter in the evaluation unit 40 in the fourth step 140 of the method 100. In particular, the determined pipe wall thickness 19 or the determined pipe inner diameter 21 is taken into account when determining the flow rate of the medium 11 through the pipe 12. The substantially radial alignment of the second ultrasonic head 24 generates a sharp ultrasonic echo 29, which allows for a precise determination of the pipe wall thickness 19. The second ultrasonic head 24 is independent of the first ultrasonic head 22 and is suitable for implementing the claimed method 100. Historical values 42 for the pipe wall thickness 19 and / or the pipe inner diameter 21 are stored in an evaluation unit 40. By comparing the determined pipe wall thickness 19 and / or the determined pipe inner diameter 21 with the associated historical values 42, corrosion on the inner side 17 of the pipe wall 13 or contamination on the inner side 17 of the pipe wall 13 can be detected. Thus, the method 100 allows for a fast and precise calibration of the flow measurement system 30 overall, as well as reliable diagnosis of the condition of the pipe 12. The operating behavior of the first flow sensor 10 can be simulated via a computer program product 50 (not shown in detail), which is designed as a digital twin of at least the first flow sensor 10.

[0038] According to a third embodiment of the claimed flow measurement system 30, the first flow sensor 10 is Figure 4The first flow sensor 10 has a first ultrasonic head 22 which is designed to emit flow measurement pulses 35 into the medium 11 during measuring operation. Figure 1The flow measurement system 30 is in the active operating state, completing the first step 110 of the claimed method 100. The first ultrasonic head 22 is aligned substantially diagonally with respect to the pipeline axis 15, based on the main propagation direction 36 of the flow measurement pulse 35. During measurement operation, a measurement signal 45 is transmitted from the first ultrasonic head 22 to the evaluation unit 40. The first flow sensor 10 also has a second ultrasonic head 24, which is arranged in the region of the first ultrasonic head 22. The second ultrasonic head 24 is aligned substantially parallel to the first ultrasonic head 22. Furthermore, the first flow sensor 10 has an ultrasonic reflector 32, which is arranged to deflect the ultrasonic pulse 25 of the second ultrasonic head 24. The ultrasonic reflector 32 is aligned such that the ultrasonic pulse 25 is emitted substantially along a radial direction 33 into the pipeline wall 13. The ultrasonic pulse 25 passes through the pipeline wall 13 and is reflected as an ultrasonic echo 29 on the inner side 17 of the pipeline wall 13 in the region opposite the first flow sensor 10. The ultrasonic echo 29 is guided to the second ultrasonic head 24 by the ultrasonic reflector 32. The emission of the ultrasonic pulse 25 and the reception of the ultrasonic echo 29 occur in a second step 120 of the claimed method 100. The second ultrasonic head 24 can be easily mounted in the first flow sensor 10 via the ultrasonic reflector 32. The first flow sensor 10 is designed in a simple and cost-effective manner. The emission of the ultrasonic pulse 25 in the radial direction 33 essentially results in a sharp ultrasonic echo 29, which allows for a particularly precise determination of the signal propagation time. The signal propagation time describes the time between the emission of the ultrasonic pulse 25 and the reception of the associated ultrasonic echo 29. Taking into account the speed of sound in the material of the pipe wall 13 and the installation position of the second ultrasonic head 24, the pipe wall thickness 19 can be determined using the signal propagation time. The determination of the pipe wall thickness 19 occurs in a third step 130 of the claimed method 100. Furthermore, at least the determined pipe wall thickness 19 is stored as a calibration parameter in the evaluation unit 40 in a fourth step 140. With the aid of the pipe wall thickness 19, also taking into account the pipe outer diameter 23, the pipe inner diameter 21 can be determined, which is likewise stored as a calibration parameter in the evaluation unit 40 in a fourth step. In addition, historical values 42 for the pipe wall thickness 19 and / or for the pipe inner diameter 21 are stored in the evaluation unit 40. By comparing the determined pipe wall thickness 19 and / or the determined pipe inner diameter 21 with the corresponding historical values 42, corrosion or contamination on the inner side 17 of the pipe 12 can be determined. An increase in the pipe inner diameter 21 is caused by corrosion of the pipe wall 13, whereas a reduction in the pipe inner diameter 21 is caused by contamination on the inner side 17 of the pipe wall 13. As a result of this contamination, the pipe 12 is narrowed. Figure 4The embodiment shown in FIG. 1 allows the claimed calibration method 100 to be integrated into measurement operation. For this purpose, the first ultrasonic head 22 and the second ultrasonic head 24 are operated in time-slice mode. The claimed method 100 can be easily incorporated into the ongoing operation of the flow measurement system 30 (not shown in detail), so that its calibration can be regularly adjusted. This allows for reliable and precise measurement operation. The operating behavior of the first flow sensor 10 can be simulated via a computer program product 50 (not shown in detail), which is designed as a digital twin of at least the first flow sensor 10.

[0039] In addition, Figure 5 1 shows a flow sensor 10 according to a third embodiment of the claimed flow measurement system 30 in a longitudinal section. Figure 5 is already installed on the pipeline 12 and is in an active operating state. Therefore, the first step 110 of the claimed method 100 is Figure 5The first flow sensor 10 has a combined ultrasonic head 28, which includes a first ultrasonic head 22 and a second ultrasonic head 24. The first ultrasonic head 22 and the second ultrasonic head 24 are independently controllable sections of the combined ultrasonic head 28. The first ultrasonic head 22 is arranged so that, during measurement operation, a flow measurement pulse 35 is emitted into the medium 11 substantially diagonally with respect to the pipeline axis 15. The second ultrasonic head 24, which is arranged adjacent to the first ultrasonic head 22, is designed to emit an ultrasonic pulse 25, independently of the first ultrasonic head 22 and, therefore, also independently of the flow measurement pulse 35, by means of which the pipeline wall thickness 19 of the pipeline 12 is determined. The ultrasonic pulse 25 is emitted by the second ultrasonic head 24 substantially diagonally with respect to the pipeline axis 15 and is deflected substantially in a radial direction 33 by an ultrasonic reflector 32. The ultrasonic reflector 32 is positioned so that the flow measurement pulse 35 can pass through it. The ultrasonic pulse 25 of the second ultrasonic head 24 passes through the pipe wall 13 essentially in a radial direction 33 and is reflected as an ultrasonic echo 29 on the inner side 17 of the pipe wall 13 in the area opposite the first flow sensor 10. The ultrasonic echo 29 reaches the ultrasonic reflector 32, by which it is directed back to the second ultrasonic head 24. The emission of the ultrasonic pulse 25 essentially in the radial direction 33 results in a sharp ultrasonic echo 29, which allows for a particularly precise determination of the signal propagation time. The signal propagation time describes the time between the emission of the ultrasonic pulse 25 and the reception of the associated ultrasonic echo 29. For this purpose, a suitable measurement signal 45 is transmitted from the integrated ultrasonic head 28 to the evaluation unit 40. Taking into account the speed of sound in the material of the pipe wall 13 and the installation position of the second ultrasonic head 24, the pipe wall thickness 19 can be determined using the signal propagation time. The determination of the pipe wall thickness 19 occurs in the third step 130 of the claimed method 100. Furthermore, the determined pipe wall thickness 19 is stored as a calibration parameter in the evaluation unit 40 in a fourth step 140. The pipe inner diameter 21 is determined in a third step 130 using the pipe wall thickness 19, also taking into account the pipe outer diameter 23. In addition, historical values 42 for the pipe wall thickness 19 and / or for the pipe inner diameter 21 are stored in the evaluation unit 40. By comparing the determined pipe wall thickness 19 and / or the determined pipe inner diameter 21 with the corresponding historical values 42, corrosion or contamination on the inner side 17 of the pipe 12 can be determined. An increased pipe inner diameter 21 is caused by corrosion of the pipe wall 13, whereas a reduction in the pipe inner diameter 21 is caused by contamination on the inner side 17 of the pipe wall 13. As a result of this contamination, the pipe 12 is narrowed. Figure 5 The embodiment shown in FIG. 1 allows the measurement operation with the flow measurement pulse 35 and the claimed method 100 to be performed substantially simultaneously. As a result, a general measurement operation is possible and the flow measurement system 30 is recalibrated at the same time. Figure 5 This embodiment is particularly suitable for applications in which permanent flow measurement is absolutely necessary and in which particularly high precision requirements arise, which necessitate substantially constant recalibration. The operating behavior of the first flow sensor 10 can be simulated via a computer program product 50 (not shown in detail), which is designed as a digital twin of at least the first flow sensor 10.

[0040] Figure 6 A schematic diagram is shown which illustrates the determination of the surface roughness in the claimed method 100 according to the functional principle. Figure 6 As an example, a second ultrasonic head 24 is shown. During the second step 120 of the method 100, the second ultrasonic head 24 emits ultrasonic pulses 25 diagonally to opposing areas on the inner side 17 of the pipe wall 13. The opposing areas of the pipe wall 13 have a surface roughness 27 that is representative of the inner side 17 of the pipe wall 13. The surface roughness 27 on the inner side 17 causes the ultrasonic pulse 25 to be reflected in different directions as multiple ultrasonic echoes 29. The intensity of the ultrasonic echoes 29 is reduced compared to the intensity of the ultrasonic pulse 25 and is reflected to the second ultrasonic head 24. The smaller the surface roughness 27, the smaller the intensity of the ultrasonic echoes 29 reflected to the second ultrasonic head 24. Conversely, the higher the intensity of the ultrasonic echoes 29 reflected to the second ultrasonic head 24, the greater the surface roughness 27. The surface roughness 27 is quantitatively determined using a numerical table or an algorithm in an evaluation unit 40 (not shown in detail), particularly by taking into account information about the material of the pipe wall 13. For this purpose, a relationship is formed between the emitted ultrasonic pulse 25 and the received ultrasonic echo 29. The determined surface roughness 27 can be stored as a calibration parameter in the evaluation unit 40. The surface roughness 27 is used for the measurement operation of the flow measurement system 30 (not shown in detail), in particular for the Hagen-Poisson equation. Alternatively or in addition, the determined surface roughness 27 is also used to quantify the progression of corrosion on the inner side 17 of the pipeline wall 13. The reflection behavior of the pipeline wall 13 according to the surface roughness 27 forms part of the operating behavior of the flow sensor 10, which can be simulated by the computer program product 50. The computer program product 50 is designed as a digital twin, by which at least the opposing pipeline wall 18 can be readjusted with respect to the surface roughness 27.

Claims

1. A method (100) for calibrating a flow measurement system (30), the flow measurement system being installed on a pipeline (12) containing a medium (11), the method comprising the following steps: a) providing, in an active operating state, the flow measurement system (30) comprising a first flow sensor (10); b) transmitting an ultrasonic pulse (25) into a pipe wall (13) of the pipe (12) by means of a first ultrasonic head or a second ultrasonic head (22, 24) of the first flow sensor (10), and receiving an ultrasonic echo (29) by means of the second ultrasonic head (24); c) determining the signal propagation time of the ultrasonic pulse (25) and the ultrasonic echo (29) and determining the pipe wall thickness (19) using the signal propagation time; d) setting calibration parameters of the first flow sensor (10), wherein the calibration parameters include the pipe wall thickness (19), Characterized in that, in step b), in order to determine the surface roughness (27) of the inner side (17) of the pipe wall (13), the ultrasonic pulse (25) is emitted in the diagonal direction into the medium (11), and the intensity of the received ultrasonic echo (29) is detected and compared with the intensity of the emitted ultrasonic pulse (25), wherein, based on the comparison, the surface roughness (27) of the inner side (17) of the pipe wall (13) is determined, and further in step d), the determined surface roughness (27) of the inner side (17) of the pipe wall (13) is set as a calibration parameter.

2. The method (100) according to claim 1, characterized in that The second ultrasonic head (24) of the first flow sensor (10) is assigned an ultrasonic reflector (32) for deflecting the ultrasonic pulses (25).

3. The method (100) according to any one of claims 1 or 2, characterized in that The first ultrasonic head (22) is designed to emit flow measurement pulses (35).

4. The method (100) according to claim 3, characterized in that In step b), the ultrasonic pulses (25) are distinguished from the flow measurement pulses (35) by an electronic filter.

5. The method (100) according to claim 4, characterized in that The electronic filter is a bandpass filter.

6. The method (100) according to claim 3, characterized in that The ultrasonic pulse (25) and the flow measurement pulse (35) according to step b) are formed in different ways by delayed transmission.

7. The method (100) according to claim 1 or 2, characterized in that The ultrasonic pulses (25) in step b) have a bandwidth of 25 kHz to 8 MHz and / or a pulse duration of 0.1 µs to 5.0 ms.

8. The method (100) according to claim 1 or 2, characterized in that Step c) is also performed using information about the material of the pipe wall (13) and / or using information about the connection of the first flow sensor (10) to the pipe (12).

9. The method (100) according to claim 1 or 2, characterized in that The pipe wall thickness (19) determined in step c) is used to determine any corrosion of the pipe (12) or any contamination of the pipe (12).

10. A flow measurement system (30) comprising a first flow sensor and a second flow sensor (10, 20), wherein: The first flow sensor (10) is designed to emit a flow measurement pulse (35) by means of a first ultrasonic head (22), and the second flow sensor (20) is designed to receive an echo (37) of the flow measurement pulse (35), wherein, for determining the pipe wall thickness (19), the first flow sensor (10) has a second ultrasonic head (24), wherein the flow measurement system (30) has an evaluation unit (40) which is designed to receive and evaluate a measurement signal (45) from the first flow sensor (10), characterised in that the evaluation unit (40) is designed to be calibrated by means of a method (100) according to any one of claims 1 to 9.

11. The flow measurement system (30) according to claim 10, characterized in that The evaluation unit (40) is designed as a local evaluation unit, which is accommodated in one of the flow sensors (10, 20) or is designed as an industrial controller.

12. A computer program product (50) designed to simulate the operating behavior of a flow measurement system (30), the flow measurement system being installed on a pipeline (12), characterized in that The flow measurement system (30) is designed according to claim 11.

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