Method for operating an ultrasonic flow measuring instrument and ultrasonic flow measuring instrument

Abstract

We operate ultrasonic flowmeters that can guarantee particularly low measurement errors for a wide range of applications. [Solution] The ultrasonic flow measuring device has an ultrasonic transducer pair with a first / second ultrasonic transducer, a third ultrasonic transducer, a holding device, and a control / evaluation unit. The holding device includes a holder and is placed on the measuring tube, the measuring tube has a measuring tube wall and a medium is present. The first / second ultrasonic transducers are placed on the holding device and form a measuring path through the holding device, the measuring tube wall, and the medium. A measurement signal transmitted from the first ultrasonic transducer is received by the second ultrasonic transducer and shifted from each other in the opposite direction of medium flow. The measurement signal passes through the holding device, the measuring tube wall, and the medium. The third ultrasonic transducer defines a first reference path through the holding device, the measuring tube wall, and the medium and is placed on the holding device. The third ultrasonic transducer is placed to receive and optionally transmit a reference signal propagating along the first reference path. The control / evaluation unit controls the ultrasonic transducers and evaluates the received signal.

Description

[Technical Field]

[0001] The present invention relates to a method for operating an ultrasonic flow measuring device, wherein the ultrasonic flow measuring device is A pair of ultrasonic transducers comprising a first ultrasonic transducer and a second ultrasonic transducer, At least one third ultrasonic transducer, It comprises at least one ultrasonic transducer holder and a control and evaluation unit. The ultrasonic transducer holding device includes at least one ultrasonic transducer holder, The ultrasonic transducer holder is positioned on a measuring tube, the measuring tube has a measuring tube wall, and a medium is present inside the measuring tube, and in particular the medium flows through the measuring tube. The first and second ultrasonic transducers are arranged on an ultrasonic transducer holder. The first ultrasonic transducer and the second ultrasonic transducer are positioned offset from each other in the direction of flow of the medium, such that a measurement path extends between the first and second ultrasonic transducers through an ultrasonic transducer holder, a measuring tube wall, and a medium, so that a measurement signal transmitted from the first ultrasonic transducer is received by the second ultrasonic transducer, and vice versa. In this case, the measurement signal passes through three materials: the ultrasonic transducer holder, the measuring tube wall, and the medium. A third ultrasonic transducer is positioned in the ultrasonic transducer holder so as to define at least one first reference path extending through the ultrasonic transducer holder, the measuring tube wall, and the medium, and the third ultrasonic transducer is formed and positioned to receive and optionally transmit a reference signal propagating along the first reference path. The control and evaluation unit is formed to control the ultrasonic transducer and to evaluate the signal received by the ultrasonic transducer. It starts with the method.

[0002] Furthermore, the present invention relates to an ultrasonic flow measuring device, A pair of ultrasonic transducers comprising a first ultrasonic transducer and a second ultrasonic transducer, At least one third ultrasonic transducer, It has at least one ultrasonic transducer holder, the ultrasonic transducer holder includes at least one ultrasonic transducer holder, the at least one ultrasonic transducer holder is positioned on a measuring tube during operation, the measuring tube has a measuring tube wall, and a medium is placed inside the measuring tube during operation, in particular, the medium flows through the measuring tube during operation. The first and second ultrasonic transducers are arranged on an ultrasonic transducer holder. The first ultrasonic transducer and the second ultrasonic transducer are positioned offset from each other in the direction of flow of the medium, such that a measurement path extends between the first and second ultrasonic transducers through an ultrasonic transducer holder, a measuring tube wall, and a medium, so that a measurement signal transmitted from the first ultrasonic transducer is received by the second ultrasonic transducer, and vice versa. In this case, the measurement signal passes through three materials: the ultrasonic transducer holder, the measuring tube wall, and the medium. A third ultrasonic transducer is positioned in the ultrasonic transducer holder so as to define at least one first reference path extending through the ultrasonic transducer holder, the measuring tube wall, and the medium, and the third ultrasonic transducer is formed and positioned to receive and optionally transmit a reference signal propagating along the first reference path. A control and evaluation unit is formed for controlling the ultrasonic transducer and for evaluating the signal received by the ultrasonic transducer. Regarding ultrasonic flow metering equipment.

[0003] Using an ultrasonic flow meter, to determine the flow velocity of a medium flowing through a measuring tube, the propagation time of a measurement signal propagating in the direction of flow and the propagation time of a measurement signal propagating in the opposite direction of flow are detected between two ultrasonic transducers, and the flow velocity is determined from the difference in propagation times.

[0004] Of particular importance to this calculation is the propagation time portion of the measurement signal transmitted from the ultrasonic transducer as it travels through the medium. This is because this portion contains information about the flow velocity of the medium. That is, if the ultrasonic transducer is located on an ultrasonic transducer holder, the delay time t of the measurement signal traveling through the ultrasonic transducer holder and / or through the wall of the measurement tube is calculated from the total propagation time of the measurement signal transmitted from the first ultrasonic transducer and detected by the second ultrasonic transducer. d That must be deducted.

[0005] In conventional ultrasonic flow measuring devices, this delay time t d t is often treated as a constant and included in the calculation of the velocity of the medium. In practice, the delay time t d This is not constant due to fluctuations in process conditions. For example, changes in the extension of the measurement path occur as a result of variations in the velocity of sound in the ultrasonic transducer holder and / or the measurement tube wall and / or the medium, which may be caused by temperature changes. Based on Snell's law of refraction, at the transition between the two mediums, the input angle of the measurement signal entering the second medium from the first medium changes as follows: sin(β1) / c1 = sin(β2) / c2 In this case, β1 is the angle of incidence with respect to the perpendicular to the interface in the first medium, c1 is the speed of sound in the first medium, β2 is the angle of refraction with respect to the perpendicular to the interface in the second medium, c2 is the speed of sound in the second medium.

[0006] The delay time t changes due to the extension of the measurement path inside the ultrasonic transducer holder and / or the measurement tube wall. d This also changes, which leads to measurement errors in the evaluation of the total propagation time, and consequently, in determining the flow velocity when the flow velocity is not considered.

[0007] The flow velocity of the medium is determined by the following relationship: v = L3 / 2 × cos(θ) × (t up -tdown ) / (t up -t d )×(t down -t d ) In this case, L3 corresponds to the measurement path segment in the medium, θ is the measurement angle of the measurement signal within the medium, t up corresponds to the propagation time of the measurement signal propagating along the measurement path in the direction opposite to the flow direction, t down corresponds to the propagation time of the measurement signal propagating along the measurement path in the flow direction, t d corresponds to the delay time, that is, the time during which the measurement signal propagates through the ultrasonic transducer holding device and / or the measuring tube wall.

[0008] From the publication International Publication No. 2023 / 274557, it is known to take into account the temperature dependence of the speed of sound in the region between the ultrasonic transducer and the measuring tube or the medium in order to determine the flow rate of a flowing medium using a clamp-on ultrasonic flow measurement device. For this purpose, the measurement device has six ultrasonic transducers, which are arranged such that two pairs of ultrasonic transducers are arranged to transmit or receive measurement signals extending obliquely through the measuring tube, and one third pair of ultrasonic transducers is arranged in an ultrasonic transducer holder surrounding the measuring tube such that the measurement signals are transmitted into the measuring tube perpendicularly to the flow direction and detected by the transducers positioned opposite each other in the diametrical direction. In this case, the speed of sound of the ultrasonic transducer holder or the medium, as well as all structural parameters such as for example the wall thickness of the measuring tube, are determined by reflection at the interface between the ultrasonic transducer holder and the measuring tube or between the fluid and the measuring tube. However, this can be problematic if the reflection becomes very weak or unmeasurable due to a very small difference in the impedance of the materials.

[0009] Building upon the prior art described above, the object of the present invention is to provide a method for operating an ultrasonic flow measuring instrument that can guarantee particularly low measurement errors for a wide range of applications. Furthermore, an object of the present invention is to provide an ultrasonic flow measuring instrument for carrying out the method according to the present invention.

[0010] According to the first teaching of the present invention, the above-mentioned problem can be solved by the method for operating the ultrasonic flow measuring device described at the beginning. The method involves the following steps, namely, - A step of transmitting a measurement signal by a first ultrasonic transducer or a second ultrasonic transducer, wherein the measurement signal propagates along the measurement path, - The measurement signal is received by the second ultrasonic transducer or the first ultrasonic transducer, and the total propagation time t total A step to identify, in this case, t total This corresponds to the total propagation time of the measurement signal between the first ultrasonic transducer and the second ultrasonic transducer, in steps. - The step of transmitting a first reference signal by a third ultrasonic transducer or another ultrasonic transducer, - The first reference signal is received by the third ultrasonic transducer, and the reference propagation time t ref A step to identify, in this case, t ref This is a step corresponding to the propagation time of the first reference signal between the ultrasonic transducer that transmits the first reference signal and the third ultrasonic transducer. - Known structural parameters of the measuring device, measured propagation time t ref and t total , and the step of determining the velocity v of the flowing medium using the sound velocity c1 of the ultrasonic transducer holder. This is resolved by including [the necessary element].

[0011] According to the present invention, the total propagation time t of the measurement signal propagating along the measurement path total In addition to the measurement of the ultrasonic transducer holder, the measuring tube wall, and the propagation time t of the reference signal through the medium, at least one other reference propagation time t refIf detection is performed, it has been found that determining the velocity v of the flowing medium is particularly accurate. This means that when determining the flow velocity, two current measurements representing the current state of the measuring device are taken into consideration.

[0012] The input values ​​to be considered above, specifically the known structural parameters of the measuring device, the sound velocity c1 of the ultrasonic transducer holder, and the measured propagation time, determine the propagation of the measured signal, particularly the current duration of the measurement path, and consequently the delay time t of the measured signal. d This can be identified with particular precision.

[0013] Considering the measured propagation time and other known structural parameters of the measuring device, the current extent of the ultrasonic transducer holder, the measuring tube wall, and the measurement path within the medium can be identified in particular.

[0014] The extension of a measurement path is understood to be a geometrical description of the measurement path. Identifying the extension of a measurement path involves at least specifying the length of each individual measurement path segment passing through different materials. In particular, the identification of the extension also includes specifying the relevant measurement angle θ within a specific range of flow velocity of the medium through which the measurement path passes.

[0015] From the extension of the measurement path, the delay time t required for the measurement signal to pass through the ultrasonic transducer holder and the measurement tube wall is determined. d This allows for the identification of the current delay time. This delay time can be advantageously taken into account when determining the flow velocity, thereby allowing for particularly high accuracy in determining the propagation time of the measurement signal transmitted in the direction of flow and in the direction opposite to the flow direction through the medium.

[0016] This method involves a delay time t d However, this is particularly advantageous when the delay time t is on the order of the propagation time of the measurement signal through the medium. Especially when the dimensions are small, d However, this can sometimes be longer than the propagation time of the measurement signal through the medium. In such a configuration, errors can be made very quickly in determining the propagation time through the medium, and consequently in determining the flow velocity.

[0017] Furthermore, the method according to the present invention can be used in measuring devices where the acoustic impedance of the measuring tube is significantly different from the acoustic impedance of the medium, thus ensuring sufficiently strong reflection, as well as in measuring devices where the acoustic impedance of the measuring tube is similar to that of the medium. For example, if the measuring tube is made of metal, a significantly different impedance exists, while if the measuring tube is made of, for example, plastic, the impedance difference is very small.

[0018] In the measuring device according to the present invention, the measurement signal and the first reference signal also pass through three materials, namely the ultrasonic transducer holder, the measuring tube wall, and the medium.

[0019] According to one configuration of the method, for each material, a parameter is defined that identifies the extent of the measurement path within that material. According to this configuration, the method determines the velocity v of the flowing medium by following the steps below, i.e., - Known structural parameters of the measuring device, measured propagation time t ref and t total The steps include identifying three unknown parameters using the sound velocity c1 of an ultrasonic transducer holder, wherein each unknown parameter identifies the extension of a measurement path within one of the three materials, and in particular the unknown parameter is a geometric parameter, preferably length or angle, step, - Identify the extension of the measurement path within the ultrasonic transducer holder, the measurement tube wall, and the medium, and determine the delay time t of the measurement signal. d A step to identify the delay time t d This corresponds to the propagation time of the measurement signal through the ultrasonic transducer holder and the wall of the measuring tube, in steps. - The velocity v of the flowing medium, and the current delay time t d Steps to identify by considering these factors It includes.

[0020] According to a favorable configuration, the velocity v of the flowing medium is calculated by a trained artificial intelligence, specifically by a trained artificial neural network, and the AI ​​takes structural parameters and measured propagation time t as input values. ref and t total The artificial intelligence receives the sound velocity c1 of the ultrasonic transducer holder and supplies at least the velocity v of the flowing medium as an output value. For this purpose, the control and evaluation unit has artificial intelligence.

[0021] Particularly advantageous is that artificial intelligence may be trained using data that is acquired or simulated using one of the methods described below.

[0022] In particular, artificial intelligence implicitly or explicitly determines the current delay time t from the input value. d It correlates with or delays t d The parameters corresponding to this are identified. Optionally, the artificial intelligence determines the current delay time t. d The system can output the total length L of the measurement path, and / or the path length L1 through the ultrasonic transducer holder, and / or the path length L2 through the measurement tube wall, and / or the path length L3 through the medium.

[0023] According to the following configuration, the method involves the following steps to calculate the unknown parameter, namely: - A step of creating a system of equations containing three equations, In this case, the first equation is: the total propagation time t of the measured signal total This equation, taking structural parameters into consideration, represents the relationship between the individual propagation times of the measurement signal across the ultrasonic transducer holder, the measurement tube wall, and the measurement path through the medium, and the second equation is given by the reference propagation time t refThe third equation, taking structural parameters into consideration, represents the relationship between the individual propagation times of the reference signal across the reference path through the ultrasonic transducer holder, the measuring tube wall, and the medium. The third equation represents the geometric relationship between the distance between the first and second ultrasonic transducers and three geometric parameters, where one geometric parameter represents the extension of the measuring path within the ultrasonic transducer holder, one geometric parameter represents the extension of the measuring path within the measuring tube wall, and one geometric parameter represents the extension of the measuring path within the medium. The system of equations includes at most three unknown parameters, each of which identifies the extent of the measurement path within one of the three materials, and in particular in this case, the unknown parameters are geometric parameters, preferably length or angle, step, - A step to solve the system of equations and identify unknown parameters. It includes.

[0024] According to one construction, the geometric parameters of the third equation are the unknown parameters that need to be identified.

[0025] In one configuration, the first ultrasonic transducer and the second ultrasonic transducer are positioned with a distance of 2A between them. The third equation, according to this configuration, describes the relationship between the half-distance A between the first and second ultrasonic transducers and three parameters A1, A2, and A3, where A1 corresponds to the ratio of the measurement path within the ultrasonic transducer holder in the axial direction with respect to the longitudinal axis of the measuring tube in the direction of connection between the first and second ultrasonic transducers, A2 corresponds to the ratio of the measurement path within the measuring tube wall in the direction of connection between the first and second ultrasonic transducers, and A3 corresponds to the ratio of the measurement path within the medium in the direction of connection between the first and second ultrasonic transducers.

[0026] Particularly preferable, the measurement path is formed symmetrically. In this case, the halfway distance A between the first ultrasonic transducer and the second ultrasonic transducer defines a point of symmetry when viewed in the axial direction of the measurement tube. Therefore, when viewed in the connection direction between the first ultrasonic transducer and the second ultrasonic transducer, the description of the measurement path before the point of symmetry corresponds to the description of the measurement path after the point of symmetry. Thus, when specifying the path length L1 through the ultrasonic transducer holder, the path length L2 through the measurement tube wall, and the path length L3 through the medium, as defined below, the path described before the point of symmetry can be doubled. Lengths A1, A2, and A3 specify the path length for one pass of the measurement signal through one material.

[0027] If the distance between ultrasonic transducers is 2A, the measurement signal will pass through all three materials by the time it reaches the interval A. Depending on the precise measuring device, and more specifically depending on the shape of the measurement path, the measurement signal will pass through region A of each material at least once.

[0028] If the measurement signal for each material passes through exactly once, the following third equation holds: A = A1 + A2 + A3 Here, A1 corresponds to the ratio of the measurement path within the ultrasonic transducer holder in the direction of connection between the first ultrasonic transducer and the second ultrasonic transducer, that is, in the axial direction with respect to the longitudinal axis of the measuring tube. A2 corresponds to the ratio of the measurement path within the measurement tube wall in the connection direction between the first ultrasonic transducer and the second ultrasonic transducer. A3 corresponds to the ratio of the measurement path within the medium in the connection direction between the first ultrasonic transducer and the second ultrasonic transducer.

[0029] For example, if the measurement path is V-shaped and the measurement signal is reflected off the outer wall of the measurement tube after passing through the medium, then the measurement signal passes through the measurement tube wall twice in region A. In this case, the following equation applies: A = A1 + 2 × A2 + A3 Here, A1 corresponds to the ratio of the measurement path within the ultrasonic transducer holder in the direction of connection between the first ultrasonic transducer and the second ultrasonic transducer, that is, in the axial direction with respect to the longitudinal axis of the measuring tube. A2 corresponds to the ratio of the measurement path within the measurement tube wall in the connection direction between the first ultrasonic transducer and the second ultrasonic transducer. A3 corresponds to the ratio of the measurement path within the medium in the connection direction between the first ultrasonic transducer and the second ultrasonic transducer.

[0030] According to one configuration, parameter A 1, A2 and A3 correspond to the unknown variables in the system of equations.

[0031] Alternatively, the unknown parameter may be the angle that defines the extension of the measurement path segment.

[0032] In a particularly advantageous configuration, the first and / or second equations of the system of equations take into account, as structural parameters, the distance B1 from the radiating element of the first ultrasonic transducer to the measuring tube and / or the distance B2 from the second ultrasonic transducer to the measuring tube and / or the distance B3 from the radiating element of the third ultrasonic transducer to the measuring tube and / or the thickness T of the measuring tube wall and / or the inner radius R of the measuring tube.

[0033] According to one configuration of the method, structural parameters are known, for example, from the specifications of the measuring instrument. According to the next configuration of the method, the thickness T of the measuring tube wall and / or the inner radius R of the measuring tube are measured by measuring the propagation time of the reflection of a first reference signal.

[0034] Basically, the distance B1 from the radiating element of the first ultrasonic transducer to the measuring tube, the distance B2 from the second ultrasonic transducer to the measuring tube, and the distance B3 from the radiating element of the third ultrasonic transducer to the measuring tube may be the same size. Alternatively, the values ​​of B1, B2, and B3 may be at least partially different.

[0035] In a preferred configuration, the measurement path L can be divided into measurement path sections L1, L2, and L3, in which case measurement path section L1 extends within the ultrasonic transducer holder, measurement path section L2 extends within the measurement tube wall, and measurement path section L3 extends within the medium. Each measurement path section L1, L2, and L3 preferably includes at least one hypotenuse of a right triangle. In this case, the measurement path sections that are continuous with each other in different materials are connected to each other via Snell's law of refraction.

[0036] The sum of the measurement path segments through which the measurement signal passes corresponds to the total path length L of the measurement path.

[0037] In other words, the following equation applies: L = L1 + L2 + L3

[0038] In another preferred configuration, the first reference path is perpendicular to the flow direction of the medium and passes through the ultrasonic transducer holder, the measuring tube wall, and the medium, so that no refraction occurs in the material transfer section. This configuration has the advantage of not adding any other unknown geometric parameters when formulating the system of equations, particularly the second equation. Rather, the relationships characterizing the material transfer section can be utilized for both the first and second equations, thereby reducing the overall number of unknown parameters in the system of equations.

[0039] In particular, in the first equation, the propagation time of the measurement signal along the measurement path through the wall of the measuring tube and the measurement path through the medium is expressed depending on the sound velocity c1 of the ultrasonic transducer holder, and / or in the second equation, the propagation time of the measurement signal along the measurement path through the wall of the measuring tube and the measurement path through the medium is expressed depending on the sound velocity c1 of the ultrasonic transducer holder.

[0040] The speed of sound c1 can be considered given and constant. Alternatively, the speed of sound may be measured via a second reference path, as further described below.

[0041] According to the following advantageous configuration, the total path length L of the measurement path, and / or the lengths of the individual measurement path sections L1, L2 and L3, and / or the refraction angle β2 of the measurement signal at the transition to the measurement tube wall, and / or the refraction angle β3 of the measurement signal at the transition to the medium, and / or the sound velocity c2 of the measurement tube wall, and / or the sound velocity c3 of the medium can be determined by solving the system of equations.

[0042] According to the following configuration, a second reference path exists, which extends only within the material of the ultrasonic transducer holder, and the sound velocity c1 of the ultrasonic transducer holder is determined by measuring the propagation time of a second reference signal propagating along the second reference path.

[0043] For example, the second reference path may extend within the ultrasonic transducer holder. Alternatively, an attachment may be provided, and the second reference path may be realized within this attachment. Importantly, the attachment is made of the same material as the ultrasonic transducer holder.

[0044] Particularly preferable, the system of equations is solved numerically while considering boundary conditions for unknown parameters to be identified. The resulting system of equations is a particularly nonlinear system and may have multiple solutions.

[0045] If the unknown parameter is a geometric parameter A1, A2, and A3 or an angle, a significant or possible range of values ​​may exist for the measuring device. Unrealizable values ​​are not considered possible solutions to the system of equations.

[0046] According to a preferred configuration, the radiating element of the ultrasonic transducer is a piezoelectric element. In this case, the piezoelectric element is preferably designed such that the aperture angle of the transmitted signal is dimensioned such that as much energy as possible propagates along the measurement path or the reference path. Basically, within the scope of the present invention, especially when formulating and solving a system of equations, the measurement signal, the first reference signal, and the second reference signal if present, are regarded as individual paths. According to this consideration, this assumption is valid, since the measurement signal is reduced to the shortest path with the shortest propagation time.

[0047] If the radiating element of the ultrasonic transducer is arranged on the inclined surface of the ultrasonic transducer holding device, as long as c1<c2 is satisfied, the angle of the measurement signal with respect to the perpendicular to the measurement tube wall, and thus the angle β1 at which the measurement signal impinges on the measurement tube wall, is smaller than the critical angle at which transmission no longer exists based on Snell's law of refraction. This condition simultaneously limits the aperture angle of the measurement signal. Preferably, the aperture angle is dimensioned such that as much energy of the measurement signal as possible propagates along the measurement path. The limitation of the aperture angle of the measurement signal also limits the possible values of A1 and A2.

[0048] The method according to the present invention has the advantage that offset errors in determining the flow velocity can be substantially avoided by taking into account the effect of changing process conditions, in particular the effect of changing sound velocities of the medium and / or the measurement tube wall and the ultrasonic transducer holding device on the extension of the measurement path, and thus on the delay time.

[0049] According to the second teaching of the present invention, the problem stated at the outset is solved by the ultrasonic flow measuring device described at the outset, in which a control and evaluation unit is configured for carrying out the method described above.

[0050] With regard to the configuration of the ultrasonic flow measuring device, reference is made to all the descriptions above and below.

[0051] In a particularly preferred configuration, the third ultrasonic transducer is positioned in the ultrasonic transducer holder such that the first reference path extends perpendicular to the flow direction of the medium through which it flows. Particularly preferred, the piezoelectric element of the third ultrasonic transducer is oriented perpendicular to the flow direction and positioned on the ultrasonic transducer holder.

[0052] The third ultrasonic transducer, in one configuration, can transmit a first reference signal and can also receive a reflected reference signal. In the following configuration, a fourth ultrasonic transducer is provided. In this configuration, a first reference path extends between the third ultrasonic transducer and the fourth ultrasonic transducer. In this case, the third ultrasonic transducer can transmit the first reference signal, the fourth ultrasonic transducer can receive the first reference signal, and vice versa.

[0053] According to another preferred configuration, the ultrasonic transducer is arranged such that there is a second reference path through which a second reference signal propagates, and the second reference path extends only inside the material of the ultrasonic transducer holder. For example, the second reference path may be formed between the first ultrasonic transducer and the third ultrasonic transducer. Alternatively, the second reference path may be formed between the third ultrasonic transducer and the second ultrasonic transducer. According to the following configuration, the second reference path may be formed between the first ultrasonic transducer and the second ultrasonic transducer.

[0054] A second reference path may be formed as part of the first reference path. In this configuration, the third ultrasonic transducer is positioned to transmit the first reference signal into the medium perpendicular to the flow direction of the medium through the ultrasonic transducer holder and the measuring tube wall. The second reference signal corresponds to the reflection of the first reference signal at the transition between the ultrasonic transducer holder and the measuring tube wall.

[0055] In another configuration, an attachment is provided on or in contact with the third ultrasonic transducer, and the third ultrasonic transducer sends a signal to the attachment, at least temporarily, and detects the reflected signal. In this case, the attachment is made of the same material as the ultrasonic transducer holder.

[0056] Particularly preferably, a reflective element for reflecting a second reference signal is formed within the ultrasonic transducer holder. For example, the reflective element may be formed as a groove within the ultrasonic transducer holder. According to the following configuration, the reflective element is formed as a material insert having a different material from the ultrasonic transducer holder.

[0057] According to the following configuration, the ultrasonic transducer is mounted on at least one ultrasonic transducer holder so as to be rigid, i.e., non-slidable, in the direction of the flow of the medium. By taking into account changes in sound velocity and the resulting changes in the measurement path and delay time according to the present invention, it is not necessary to reorient or recalibrate the ultrasonic transducer when process conditions change.

[0058] In one configuration, the ultrasonic transducer holder has a single ultrasonic transducer holder on which first, second, and third ultrasonic transducers are arranged. In particular, the ultrasonic transducer holder has at least two wedge-shaped regions, and the first and second ultrasonic transducers are each positioned in the inclined portion of the wedge-shaped region, so that the ultrasonic transducers transmit the measurement signal in the direction of the medium or measuring tube at a constant angle.

[0059] In another configuration, the ultrasonic transducer holder has at least two ultrasonic transducer holders, the at least two of which are formed at least partially in a wedge shape, the first ultrasonic transducer is placed on the first ultrasonic transducer holder, and the second ultrasonic transducer is placed on the second ultrasonic transducer holder. Preferably, according to this configuration, the third ultrasonic transducer is placed on the first ultrasonic transducer holder or on the second ultrasonic transducer holder.

[0060] According to the following configuration, the ultrasonic transducer holder has three ultrasonic transducer holders, in which case the first ultrasonic transducer is placed on the first ultrasonic transducer holder, the second ultrasonic transducer is placed on the second ultrasonic transducer holder, and the third ultrasonic transducer is placed on the third ultrasonic transducer holder.

[0061] According to the following configuration, the ultrasonic flow measuring instrument has a maximum of three ultrasonic transducers or a maximum of four ultrasonic transducers. This allows for the determination of the current delay time to be carried out particularly efficiently with a simple structure.

[0062] Numerous possibilities exist for constructing and developing the methods and ultrasonic flow measuring devices according to the present invention. These possibilities are referred to in the patent claims dependent on the independent claims, as well as the embodiments described below in relation to the drawings. [Brief explanation of the drawing]

[0063] [Figure 1] This figure shows an example of an ultrasonic flow metering device according to the present invention. [Figure 2] This figure shows another example of an ultrasonic flow metering device. [Figure 3] This figure shows another example of an ultrasonic flow metering device. [Figure 4] This figure shows another example of an ultrasonic flow metering device. [Figure 5] This figure shows another example of an ultrasonic flow metering device. [Figure 6]This figure shows another example of an ultrasonic flow metering device. [Figure 7] This figure shows another example of an ultrasonic flow metering device. [Figure 8] This figure shows an example of the method according to the present invention. [Figure 9] This figure shows a comparison between the conventional method for determining the flow velocity v and the method for determining the flow velocity according to the present invention. [Figure 10] This figure shows another embodiment of the method according to the present invention.

[0064] Figure 1 shows a first embodiment of the ultrasonic flow measuring device 1. The ultrasonic flow measuring device 1 has a first ultrasonic transducer 2 and a second ultrasonic transducer 3, which are arranged in an ultrasonic transducer holder 5. In the illustrated embodiment, the ultrasonic transducer holder 5 includes an ultrasonic transducer holder, which has two wedge-shaped regions, and the first ultrasonic transducer 2 and the second ultrasonic transducer 3 are each arranged in the inclined portion of the wedge.

[0065] The ultrasonic transducer holder 5 is positioned on the measuring tube 6, and during operation, the medium 12 flows through this measuring tube. The first and second ultrasonic transducers 2 and 3 are positioned on the ultrasonic transducer holder 5 such that a symmetrical V-shaped measuring path 7 extends between them, passing through the ultrasonic transducer holder 5, the measuring tube wall 8, and the medium present in the measuring tube 6.

[0066] For clarity, lengths A1, A2, and A3 are shown in the first half of the measurement path, and angles β1, β2, and β3 are shown in the second half of the measurement path. Based on the symmetrical configuration, lengths A1-A3 are also present in the second half of the measurement path, and angles β1, β2, and β3 are also present in the first half of the measurement path. Similarly, relevant measurement angles θ for determining flow velocity are also illustrated.

[0067] Furthermore, a third ultrasonic transducer 4 is provided, and the third ultrasonic transducer 4 is similarly positioned in the ultrasonic transducer holder 5, in this case, the third ultrasonic transducer 4 is positioned between the first ultrasonic transducer 2 and the second ultrasonic transducer 3. Furthermore, the third ultrasonic transducer 4 is positioned in the ultrasonic transducer holder 5 so as to define a first reference path 9 extending through the ultrasonic transducer holder 5, the measuring tube wall 8, and the medium, perpendicular to the flow direction 19 of the medium 12. In the illustrated embodiment, the radiating elements 10a, 10b, and 10c of the first ultrasonic transducer 2, the second ultrasonic transducer 3, and the third ultrasonic transducer 4 have the same spacing B with respect to the measuring tube 6.

[0068] Furthermore, the ultrasonic flow measuring device 1 has a control and evaluation unit 11 for controlling the ultrasonic transducers 2, 3, and 4, and for evaluating the signals detected by the ultrasonic transducers 2, 3, and 4.

[0069] To determine the flow velocity v of the medium, the propagation time of a first measurement signal propagating in the flow direction 19 along the measurement path 7 between the first ultrasonic transducer 2 and the second ultrasonic transducer 3, and the propagation time of a second measurement signal propagating in the opposite direction to the flow direction 19 between the second ultrasonic transducer 3 and the first ultrasonic transducer 2 are measured. The flow velocity v is determined from the difference in propagation times.

[0070] In this case, however, only a portion of the measurement signal contains information about the flow velocity v of the medium 12 as it passes through. That is, when determining the propagation time of the measurement signal, the propagation time of the measurement signal passing through the ultrasonic transducer holder 5 and the measurement tube wall 8 is determined by the delay time t. d It is subtracted from the total propagation time.

[0071] In this case, if the process conditions change, for example, if the medium temperature or ambient temperature changes, the delay time t d It is not constant.

[0072] With the illustrated apparatus, advantageously, if the structural boundary conditions are known, the current delay time t of the measuring device can be measured.d It is possible to identify this.

[0073] For this purpose, a system of equations is formulated that includes three equations and three unknown parameters, in which case the unknown parameters specify the extent of the measurement path 7 in one of the materials of the ultrasonic transducer holder 5, the measuring tube wall 8, and the medium 12.

[0074] The first equation is the total propagation time t of the measurement signal propagating along the measurement path 7 between the first ultrasonic transducer 2 and the second ultrasonic transducer 3. total This represents the following relationship regarding the propagation time:

number

[0075] In this case, A1 is the region viewed in the axial direction as the measurement signal travels through the ultrasonic transducer holder 5, A2 is the region viewed in the axial direction as the measurement signal travels through the measurement tube wall 8, and A3 is the region viewed in the axial direction as the measurement signal travels through the medium 12.

[0076] B, R, and T are structural parameters: B corresponds to the distance from the radiating elements 10a, 10b, and 10c of the ultrasonic transducers 2, 3, and 4 to the measuring tube 6. This is the same for all three ultrasonic transducers 2, 3, and 4 in this embodiment. R is the inner radius of the measuring tube 6, and T is the thickness of the measuring tube wall 8. These parameters are known in the equations described above. For example, these parameters can be obtained by measurement or estimation, or by predetermined specifications of the measuring instrument.

[0077] Furthermore, c1 is the sound velocity of the ultrasonic transducer holder 5. This sound velocity is also known. In the illustrated embodiment, the sound velocity c1 can be measured. For this purpose, a second reference path 13 extends inside the ultrasonic transducer holder 5 between the first ultrasonic transducer 2 and the third ultrasonic transducer 4, and the second reference signal transmitted from the first ultrasonic transducer 2 is reflected by a reflective element 14, which is formed as a groove in the illustrated embodiment, and received by the third ultrasonic transducer 4.

[0078] Each summation term in equation (1) represents the propagation time through each individual material. The first summation term corresponds to the propagation time through the ultrasonic transducer holder 5, the second summation term corresponds to the propagation time through the measuring tube wall 8, and the third summation term corresponds to the propagation time through the medium.

[0079] According to Snell's law of refraction at each material transition point, the individual additive terms are related to one another. More specifically, this relationship, and by assuming that the extension of the measurement path 7 in each material corresponds to the hypotenuse of a right triangle, allows us to express the sound velocity c2 in the measurement tube wall 8 and the sound velocity c3 in the medium 12 as follows:

number

number

[0080] The second equation represents the total propagation time of the reference signal transmitted from the third ultrasonic transducer 4 and propagating through the ultrasonic transducer holder 5, the measuring tube wall 8, and the medium 12 along a first reference path 9 perpendicular to the flow direction 12.

[0081] The following equation holds for this propagation time, and in this case, the sound speeds c2 and c3 are similarly substituted by the relationship described above:

number

[0082] The third equation represents the geometric relationship between half the spacing A between the first ultrasonic transducer 2 and the second ultrasonic transducer 3, and three parameters A1, A2 and A3, where A1 corresponds to the proportion of the measurement path 7 in the ultrasonic transducer holding device in the connection direction between the first ultrasonic transducer 2 and the second ultrasonic transducer 3, A2 corresponds to the proportion of the measurement path 7 in the measurement tube wall 8 in the connection direction between the first ultrasonic transducer 2 and the second ultrasonic transducer 3, and A3 corresponds to the proportion of the measurement path 7 in the medium 12 in the connection direction between the first ultrasonic transducer 2 and the second ultrasonic transducer 3. (3) A3=A-A1-A2

[0083] Therefore, the three equations in total have three unknown parameters, namely A1, A2 and A3.

[0084] This system of equations can be solved numerically, for example.

[0085] To determine the solution, the parameters A1 and A2 have boundary conditions, which arise from the generally possible range of the angle β1 of the measurement signal relative to the direction perpendicular to the measurement tube. If c1<c2, the angle β 1 max is limited according to Snell's law of refraction by the critical angle beyond which transmission no longer exists.

[0086] If the assumed value range of the speed of sound c3 of the medium is basically known, the boundary conditions, in particular the minimum angle β 1 min and the maximum angle β 1 max can be determined as follows using the estimated speed of sound c2 of the measurement tube.

[0087] The following formula applies: β crit 1 =asin(c1 / c2 推定値 )→β 1 max =β crit 1 (where c1<c 2推定値 )

[0088] Therefore, regarding A1, the following applies: A 1 min =B × tan(β) 1 min ) × (1 - ε / 100) A 1 max =B × tan(β) 1 max ) × (1 + ε / 100) β 2 min =asin(c 2 推定値 ×sin(β 1 min / c1)) β 2 max =asin(c 2 推定値 ×sin(β 1 max / c1)) β 2 max =β 2 max,moeglich (However, β 2 max ≥β 2 max,moeglich ) For A2, the following boundary conditions are obtained: A 2 min =T × tan(β) 2 min ) × (1 - ε / 100) A 2 max =T × tan(β) 2 max ) × (1 + ε / 100)

[0089] In the above equation, ε represents the possible deviations of the inputs of the structural parameters B, T, or R. 2 max,moeglich This represents the maximum possible angle with respect to β2.

[0090] Therefore, from the values ​​for A1, A2, and A3, the values ​​of sound velocities c2 and c3, as well as path lengths L1, L2, and L3 can be determined, in which case L1 is the path length through the ultrasonic transducer holder 5, L2 is the path length through the measuring tube wall 8, and L3 is the path length through the medium.

[0091] Regarding the path length, the following equation holds:

number

number

number

[0092] Based on the known path lengths L1-L3 and sound velocities c1-c3, the propagation time through the ultrasonic transducer holder 5 and the measuring tube wall 8 is determined, and consequently, the current delay time t is calculated. d It is possible to identify this.

[0093] Therefore, when determining the flow velocity according to the following relationship, the current delay time t d This can be taken into consideration, which reduces the overall error in determining the flow velocity. v = L3 / 2 × cos(θ) × (t up -t down ) / (t up -t d )×(t down -t d )

[0094] Figure 2 shows another embodiment of the ultrasonic flow measuring device 1 located in the measuring tube 6. The measuring tube 6 is equipped with an ultrasonic transducer holder 5, which in the illustrated embodiment has two ultrasonic transducer holders 5a and 5b. In the illustrated embodiment, the first ultrasonic transducer holder 5a is located above the longitudinal axis 15 of the measuring tube, and the second ultrasonic transducer holder 5b is located below the longitudinal axis 15 of the measuring tube.

[0095] In this case, the ultrasonic transducer holder 5a, positioned above the longitudinal axis 15 of the measuring tube, and the ultrasonic transducer holder 5b, positioned below the longitudinal axis 15 of the measuring tube, each have a single inclined surface. The first ultrasonic transducer 2 is positioned on the inclined surface of the first ultrasonic transducer holder 5a. The second ultrasonic transducer 3 is positioned on the inclined surface of the second ultrasonic transducer holder 5b. Between the first ultrasonic transducer 2 and the second ultrasonic transducer 3, there is a measurement path 7 through which the measurement signal propagating between the first ultrasonic transducer 2 and the second ultrasonic transducer 3 passes. In the illustrated embodiment, the measurement path 7 does not have reflections on the measuring tube wall 8. Rather, the measurement path 7 is substantially formed in a Z shape.

[0096] Furthermore, a fourth ultrasonic transducer 16 is positioned in the ultrasonic transducer holder 5a, which is located above the longitudinal axis 15 of the measuring tube, and which transmits a signal perpendicular to the longitudinal axis 15 of the measuring tube during operation. A third ultrasonic transducer 4 is positioned on the second ultrasonic transducer holder. The third ultrasonic transducer 4 and the fourth ultrasonic transducer 16 share a first reference path 9.

[0097] Furthermore, a groove-shaped reflective element 14 is positioned within the first ultrasonic transducer holder 5a. A second reference path 13 is formed between the first ultrasonic transducer 2 and the fourth ultrasonic transducer 16, in which case the second reference signal transmitted from the first ultrasonic transducer 2 is reflected to the fourth ultrasonic transducer 16 by the reflective element 14.

[0098] For this embodiment, the three relevant equations are as follows:

number

number

[0099] As mentioned above, it is assumed that the parameters B, T, R, A, and c1 are known. In particular, the speed of sound c1 can be measured using a second reference signal.

[0100] By solving the system of equations, parameter A 1, A2 and A3 can be calculated.

[0101] Therefore, from parameters A1, A2, and A3, the sound speeds c2 and c3, as well as the path lengths L1, L2, and L3, can be determined as follows:

number

number

number

[0102] From the calculated path length, the current delay time td and, consequently, the flow velocity v of the medium can be calculated with particular accuracy.

[0103] Alternatively, instead of lengths A1, A2, and A3, we can use the angles of a right triangle in the material as unknown parameters. In this case, the three equations are as follows: (1)t / =2×B / c1×cos(β1)+4×T×cos(π / 2-β1) / c1×cos(2×β2-π / 2)+4×R×cos(π / 2-β1) / c1×cos(2×β3-π / 2) (2)t ⊥ =2×B / c1+2×T×cos(π / 2-β1) / c1×cos(π / 2-β2)+2×R×cos(π / 2-β1) / c1×cos(π / 2-β3) (3)A=B×tan(β1)+T×tan(β2)+R×tan(β3)

[0104] In this case, angles β1, β2, and β3 are unknown parameters that need to be identified.

[0105] Figure 3 shows another embodiment of the ultrasonic flow measuring device 1, in which the ultrasonic transducer holder 5 is located in the measuring tube 6, and the first ultrasonic transducer 2, the second ultrasonic transducer 3, and the third ultrasonic transducer 4 are located in the ultrasonic transducer holder 5. The first ultrasonic transducer 2 and the second ultrasonic transducer 3 form a V-shaped measuring path 7 between them.

[0106] Unlike the first embodiment, the measurement signal is reflected at the outer wall 8b of the measuring tube 6, rather than at the inner wall 8a of the measuring tube 6. For this purpose, the ultrasonic transducer holder 5b, located below the longitudinal axis of the measuring tube, is provided with a groove 17 for realizing a material transfer section. The ultrasonic transducer holder 5b is optionally provided in the illustrated embodiment, i.e., it may not be present depending on the configuration. However, the ultrasonic transducer holder 5b located on the opposite side from the first ultrasonic transducer holder 5a improves the mechanical stability of the measuring device, particularly when the flow measuring instrument is attached to a plastic measuring tube having a small diameter.

[0107] The three related equations in the system of equations, with respect to the illustrated example, are as follows:

number

number

[0108] As mentioned above, it is assumed that the parameters B, T, R, A, and c1 are known. In particular, the speed of sound c1 can be measured using a second reference signal.

[0109] By solving the system of equations, parameter A 1, A2 and A3 can be calculated.

[0110] Therefore, from parameters A1, A2, and A3, the sound speeds c2 and c3, as well as the path lengths L1, L2, and L3, can be determined as follows:

number

number

number

[0111] From the calculated path length, the current delay time td and, consequently, the flow velocity of the medium can be calculated with particular accuracy.

[0112] The following three figures, Figures 4, 5, and 6, show excerpts of the ultrasonic flow measuring device 1, illustrating in detail the possible configurations of the second reference path 9.

[0113] In the embodiment shown in Figure 4, a second reference path 9 is positioned between the first ultrasonic transducer 2 and the third ultrasonic transducer 4. For this purpose, a groove-shaped reflective element 14 is formed inside the ultrasonic transducer holder 5.

[0114] Figure 5 shows an embodiment in which a second reference path 9 is formed between the first ultrasonic transducer 2 and the second ultrasonic transducer 3.

[0115] Figure 6 shows an embodiment in which an attachment 5c made of the same material as the ultrasonic transducer holder 5 is placed on the third ultrasonic transducer 4. A second reference signal is transmitted from the third ultrasonic transducer 4 to the attachment 5c, which is reflected off the edge of the attachment 5c and then received again.

[0116] Figure 7 shows another embodiment of the ultrasonic flow measuring device 1, in which the ultrasonic transducer holder 5 has two ultrasonic transducer holders 5a and 5b. The first ultrasonic transducer holder 5a houses the first ultrasonic transducer 2 and the third ultrasonic transducer 4, while the second ultrasonic transducer holder 5b houses the second ultrasonic transducer 3. A separator 18 is placed between the first ultrasonic transducer 2 and the second ultrasonic transducer 3. When not fixed, the distance between the first ultrasonic transducer holder 5a and the second ultrasonic transducer holder 5b can be adjusted within the scope of the calibration process before starting operation. Similarly, various separators 18 may be suitable for various applications. Optionally, the separator 18 can also be removed again after installation. The installation of the ultrasonic transducers 2 and 3 using the separator ensures that the ultrasonic transducers 2 and 3 have a distance 2A from each other.

[0117] Figure 8 shows an embodiment of method 20 for operating the ultrasonic flow measuring device 1, in which case the ultrasonic flow measuring device 1 is formed as shown in Figure 1.

[0118] Method 20 has the following steps: - Step 21, which involves transmitting a measurement signal using a first ultrasonic transducer 2 or a second ultrasonic transducer 3, wherein the measurement signal propagates along the measurement path 7. - The measurement signal is received by the second ultrasonic transducer 3 or the first ultrasonic transducer 2, and the propagation time t total Step 22, which identifies, in this case, t total Step 22 corresponds to the total propagation time of the measurement signal between the first ultrasonic transducer 2 and the second ultrasonic transducer 3. - Step 23, transmit the reference signal by a third ultrasonic transducer 4 or another ultrasonic transducer. - The reference signal is received by the third ultrasonic transducer 4, and the propagation time t ref Step 24 to identify, in this case, t refcorresponds to the propagation time of the reference signal between the ultrasonic transducer that transmits the reference signal and the third ultrasonic transducer 4, step 24, - Step 25 of creating a system of equations including three equations based on known structural parameters A, B, R and T, and based on the speed of sound c1 of the ultrasonic transducer holding device 5, In this case, the first equation represents the relationship between the total propagation time t of the measurement signal total and the individual propagation times of the measurement signal over the measurement path 7 passing through the three materials, the second equation represents the relationship between the reference propagation time t ref and the individual propagation times of the reference signal over the reference path 9 passing through the three materials, and the third equation represents the geometric relationship between the distance between the first ultrasonic transducer 2 and the second ultrasonic transducer 3 and one geometric parameter for each of the measurement paths of the three materials, The system of equations contains a maximum of three unknown parameters, each one unknown parameter specifying the extension of the measurement path in the material, in particular in this case the unknown parameters are geometric parameters, preferably lengths or angles, step 25, - Step 26 of solving the system of equations and determining the unknown parameters, - Step 27 of specifying the extension L of the measurement path and specifying the delay time t of the measurement signal d , the delay time t d corresponds to the propagation time of the measurement signal through the ultrasonic transducer holding device and the measurement tube wall, step 27, - Step 28 of specifying the velocity v of the flowing medium in consideration of the current delay time t d .

[0119] The extension L of the measurement path 7 is understood to be a geometric description of the measurement path 7. In detail, the lengths of the measurement path segments L1, L2 and L3 are specified, that is, the angles β1, β2 and β3 are also specified. From the angle β3, the measurement angle θ is specified. For the V-shaped extension of the measurement path shown in Figure 1, sin(θ)=(4×R) / L3 holds true.

[0120] The illustrated method can largely avoid offset errors that may arise from the specific dependence of flow velocity on sound velocity for different materials, especially when the dimensions of the measuring device are small. This is true even when the basic assumptions have some degree of inaccuracy, as shown in Figure 9 below.

[0121] Figure 9 shows a comparison between conventional methods for determining the velocity v of a flowing fluid, particularly those that do not consider changes in delay time due to changes in the velocity of sound in the medium and the wall of the measuring tube, and methods for determining the velocity according to the present invention. To demonstrate the significant advantages of the method according to the present invention, it is shown here what happens when the input of structural parameters is somewhat inaccurate, i.e., does not fully correspond to reality. That is, the geometric constant (GK) determined by the structural parameters is not equal to 1 here. In the illustrated embodiment, a value of 24.5 mm was input as the radius of the measuring tube. However, in reality, the radius was 25 mm. In contrast, methods known by the prior art correctly accounted for the structural parameters (GK=1).

[0122] At a glance, this diagram shows that when the speed of sound in a medium changes, the error in determining the flow velocity using conventional methods increases rapidly and significantly.

[0123] In contrast, the method of the present invention can effectively compensate for changes in the velocity of sound in the medium. As illustrated here, even when there is inaccuracy in the input of structural parameters, offset errors in determining the flow velocity can be almost completely avoided. In the illustrated embodiment, when the velocity of sound changes between 1100 m / s and 1800 m / s, the peak-to-peak error is a maximum of 1.8%.

[0124] Figure 10 shows another embodiment of method 20 for operating an ultrasonic flow measuring instrument formed as shown in Figure 1. Unlike the configuration in Figure 1, the flow velocity is not necessarily determined via the system of equations described above.

[0125] The control and evaluation unit 11 has a trained artificial intelligence that determines the flow velocity v of the medium on the basis of the input of structural input parameters and the propagation time t total and t ref as well as the speed of sound c1 of the ultrasonic transducer holding device.

[0126] This method comprises the following steps: - Step 21 of transmitting a measurement signal by the first ultrasonic transducer 2 or the second ultrasonic transducer 3, wherein the measurement signal propagates along a measurement path 7, - Step 22 of receiving the measurement signal by the second ultrasonic transducer 3 or the first ultrasonic transducer 2 and determining the total propagation time t total , wherein t total corresponds to the total propagation time of the measurement signal between the first ultrasonic transducer 2 and the second ultrasonic transducer 3, - Step 23 of transmitting a first reference signal by the third ultrasonic transducer 4 or a further ultrasonic transducer 16, - Step 24 of receiving the first reference signal by the third ultrasonic transducer 4 and determining the reference propagation time t ref , wherein t ref corresponds to the propagation time of the first reference signal between the ultrasonic transducer 4, 16 transmitting the first reference signal and the third ultrasonic transducer 4, - Step 28 of determining the velocity v of the flowing medium using known structural parameters of the measuring device, the measured propagation times t ref and t total , and the speed of sound c1 of the ultrasonic transducer holding device 5.

[0127] This method also has the advantage that a particularly accurate value of the flow velocity can be calculated using the measurement of the propagation time according to the invention and the known structural parameters as well as the speed of sound c1. This is because, by corresponding training, the artificial intelligence develops an error correction for the relationship between the flow velocity and the varying speed of sound of the medium and / or the measuring tube wall and / or the ultrasonic transducer holding device. DESCRIPTION OF THE REFERENCE SIGNS

[0128] 1 Ultrasonic flow measurement equipment 2. First ultrasonic transducer 3. Second ultrasonic transducer 4. Third ultrasonic transducer 5. Ultrasonic transducer holding device 5a, 5b Ultrasonic transducer holder 5c Attachment 6 Measuring tube 7. Measurement path 8 Measuring tube wall 8a Inner wall of measuring tube 8b Measuring tube outer wall 9. Reference pathway 10a, 10b, 10c Radiation elements 11 Control and Evaluation Unit 12 Medium 13. Second reference pathway 14 Reflection elements 15. Longitudinal axis of the measuring tube 16. Fourth ultrasonic transducer 17 Groove 18 Separator 19. Flow direction of the medium 20. Method for operating an ultrasonic flow measuring instrument. 21. Transmission of measurement signals 22 Receiving the measurement signal 23. Transmission of reference signal 24 Receiving the reference signal 25. Creating a system of equations containing three equations 26 Solving a System of Equations 27 Identification of the extension L of the measurement path and the delay time t of the measurement signal d Identification 28. Determination of the velocity v of the flowing medium.

Claims

1. A method (20) for operating an ultrasonic flow measuring device (1), wherein the ultrasonic flow measuring device (1) is A pair of ultrasonic transducers comprising a first ultrasonic transducer (2) and a second ultrasonic transducer (3), At least one third ultrasonic transducer (4), It comprises at least one ultrasonic transducer holder (5) and a control and evaluation unit (11), The ultrasonic transducer holding device (5) includes at least one ultrasonic transducer holder (5a, 5b), The ultrasonic transducer holder (5) is positioned on the measuring tube (6), the measuring tube (6) has a measuring tube wall (8), and a medium (12) is present inside the measuring tube (6), and in particular the medium (12) flows through the measuring tube (6), The first and second ultrasonic transducers (2, 3) are arranged on the ultrasonic transducer holder (5), The first ultrasonic transducer (2) and the second ultrasonic transducer (3) form a measurement path (7) between them, extending through the ultrasonic transducer holder (5), the measuring tube wall (8), and the medium (12), so that a measurement signal transmitted from the first ultrasonic transducer (2) is received by the second ultrasonic transducer (3), and vice versa, and so that they are offset from each other in the direction of flow of the medium (12), in which case the measurement signal passes through three materials, namely the ultrasonic transducer holder (5), the measuring tube wall (8), and the medium (12). The third ultrasonic transducer (4) is positioned in the ultrasonic transducer holder (5) to define at least one first reference path (9) extending through the ultrasonic transducer holder (5), the measuring tube wall (8), and the medium (12), and the third ultrasonic transducer (4) is configured and positioned to receive and optionally transmit a reference signal propagating along the first reference path (9). The control and evaluation unit (11) is configured to control the ultrasonic transducers (2, 3, 4, 16) and to evaluate the signals received by the ultrasonic transducers (2, 3, 4, 16). In the method, The method (20) involves the following steps, namely, - Step (21) of transmitting the measurement signal by the first ultrasonic transducer (2) or the second ultrasonic transducer (3), wherein the measurement signal propagates along the measurement path (7), - The measurement signal is received by the second ultrasonic transducer (3) or the first ultrasonic transducer (2), and the total propagation time t ｔｏｔａｌ A step (22) to identify, in this case, t ｔｏｔａｌ Step (22) corresponds to the total propagation time of the measurement signal between the first ultrasonic transducer (2) and the second ultrasonic transducer (3). - Step (23) of transmitting the first reference signal by the third ultrasonic transducer (4) or another ultrasonic transducer (16), - The third ultrasonic transducer (4) receives the first reference signal and the reference propagation time t ｒｅｆ A step (24) to identify, in this case, t ｒｅｆ Step (24) corresponds to the propagation time of the first reference signal between the ultrasonic transducer (4, 16) that transmits the first reference signal and the third ultrasonic transducer (4). - Known structural parameters of the measuring device, measured propagation time t ｒｅｆ and t ｔｏｔａｌ , and the sound velocity c of the ultrasonic transducer holding device (5) １ (28) A step in determining the velocity v of the flowing medium using A method characterized by including

2. The above method involves the following steps to determine the velocity v of the flowing medium, namely, - the known structural parameter of the measuring device, and the measured propagation time t ｒｅｆ and t ｔｏｔａｌ , and the speed of sound c of the ultrasonic transducer holding device (5) １ to identify three unknown parameters, wherein each one unknown parameter specifies the extension of the measurement path in one of the three materials, and in particular the unknown parameters are geometric parameters, preferably lengths or angles, - Identify the extent of the measurement path (7) within the ultrasonic transducer holder (5), the measuring tube wall (8), and the medium (12), and determine the delay time t of the measurement signal. ｄ A step of identifying the delay time t ｄ This corresponds to the propagation time of the measurement signal through the ultrasonic transducer holding device (5) and the measuring tube wall (8), in steps. - The velocity v of the flowing medium is set to the current delay time t. ｄ Step (28) to identify by considering the following: The method (20) according to claim 1, characterized by including the following.

3. The velocity v of the flow medium (12) is calculated by a trained artificial intelligence, specifically by a trained artificial neuronal network, and the artificial intelligence takes the structural parameters and the measured propagation time t as input values. ｒｅｆ and t ｔｏｔａｌ , and the sound velocity c of the ultrasonic transducer holding device (5) １ The method (20) according to claim 1 or 2, characterized in that the artificial intelligence receives the signal and supplies at least the velocity v of the flow medium (12) as an output value.

4. The above method involves the following steps to calculate the unknown parameter, namely, - Step (25) of creating a system of equations that includes three equations, In this case, the first equation is the total propagation time t of the measurement signal. ｔｏｔａｌ The second equation, taking into account the structural parameters, represents the relationship between the individual propagation times of the measurement signal across the measurement path (7) through the ultrasonic transducer holder (5), the measurement tube wall (8), and the medium (12), where the reference propagation time t is given by the second equation. ｒｅｆ The third equation represents the relationship between the individual propagation times of the reference signal across the reference path through the ultrasonic transducer holder (5), the measuring tube wall (8), and the medium (12), taking into account the structural parameters, and the third equation represents the geometric relationship between the distance between the first ultrasonic transducer (2) and the second ultrasonic transducer (3) and three geometric parameters, in which case one geometric parameter represents the extension of the measuring path (7) within the ultrasonic transducer holder (5), one geometric parameter represents the extension of the measuring path (7) within the measuring tube wall (8), and one geometric parameter represents the extension of the measuring path (7) within the medium (12). The system of equations includes at most three unknown parameters, each of which identifies the extent of the measurement path (7) within one of the three materials, and in particular in this case, the unknown parameters are geometric parameters, preferably length or angle, step (25), - Step (26) to solve the system of equations and identify the unknown parameters. The method (20) according to claim 2 or 3, characterized by including the following:

5. The first ultrasonic transducer (2) and the second ultrasonic transducer (3) are arranged with a distance of 2A between them, and the third equation is given by the distance A which is half the distance between the first ultrasonic transducer (2) and the second ultrasonic transducer (3), and the three parameters A １ , A ２ and A ３ This represents the relationship between A and B, where A １ This corresponds to the ratio of the measurement path (7) within the ultrasonic transducer holder (5) in the connection direction between the first ultrasonic transducer (2) and the second ultrasonic transducer (3), A ２ This corresponds to the ratio of the measurement path (7) within the measurement tube wall (8) in the connection direction between the first ultrasonic transducer (2) and the second ultrasonic transducer (3), A ３ The method (20) according to any one of claims 1 to 4, characterized in that corresponds to the ratio of the measurement path (7) in the medium in the connection direction between the first ultrasonic transducer (2) and the second ultrasonic transducer (3).

6. The first and / or second equations of the equation system are defined as the distance B from the radiating element (10a) of the first ultrasonic transducer (2) to the measuring tube (6) as a structural parameter. １ and / or the distance B from the second ultrasonic transducer (3) to the measuring tube (6) ２ and / or the distance B from the radiating element (10b) of the third ultrasonic transducer (4) to the measuring tube (6) ３ The method (20) according to any one of claims 1 to 5, characterized in that the thickness T of the measuring tube wall (8) and / or the inner radius R of the measuring tube (6) are taken into consideration, and in particular in this case the values ​​of these parameters are known.

7. The measurement path (7) is defined as measurement path section L １ , L ２ and L ３ Divided into the measurement path section L １ It extends within the ultrasonic transducer holding device (5), and the measurement path section L ２ It extends within the wall (8) of the measuring tube, and the measurement path section L ３ It extends within the medium (12), and each measurement path section L １ , L ２ , L ３ The method (20) according to any one of claims 1 to 6, characterized in that it includes at least one hypotenuse of a right triangle.

8. The method (20) according to any one of claims 1 to 7, characterized in that the first reference path (9) passes through the ultrasonic transducer holder (5), the measuring tube wall (8), and the medium (12) in a direction perpendicular to the flow direction of the medium, thereby preventing refraction in the material transfer section.

9. In the first equation, the propagation time of the measurement signal along the measurement path (7) passing through the measurement tube wall (8) and the measurement path (7) passing through the medium (7) is given by the sound velocity c of the ultrasonic transducer holder (5). １ The second equation expresses the propagation time of the measurement signal along the measurement path (7) through the measurement tube wall (8) and the measurement path (7) through the medium, depending on the sound velocity c of the ultrasonic transducer holder (5). １ A method (20) according to any one of claims 1 to 8, characterized by being expressed by depending on.

10. By solving the system of equations, the total path length L of the measurement path and / or the individual measurement path sections L can be determined. １ , L ２ and L ３ The length of and / or the angle β of incidence of the measurement signal into the measuring tube wall (8). ２ , and / or the angle of incidence β of the measurement signal to the medium (12) ３ , and / or the sound velocity c of the measuring tube wall (8) ２ , and / or the speed of sound c of the medium (12) ３ A method (20) according to any one of claims 1 to 9, characterized by specifying the following.

11. A second reference path (13) exists, and the second reference path (13) extends only inside the material of the ultrasonic transducer holder (5), and the sound velocity c of the ultrasonic transducer holder (5) １ The method (20) according to any one of claims 1 to 10, characterized in that it is identified by measuring the propagation time of a second reference signal propagating along the second reference path (9, 13).

12. The method (20) according to any one of claims 1 to 11, characterized by numerically solving a system of equations while considering boundary conditions of unknown parameters to be specified.

13. The distance B from the radiating element (10b) of the third ultrasonic transducer (4) to the measuring tube (6) ３ The method (20) according to any one of claims 1 to 12, characterized in that the thickness T of the measuring tube wall (8) and / or the inner radius R of the measuring tube (6) are measured by measuring the propagation time by reflection of the first reference signal.

14. An ultrasonic flow measuring device (1), A pair of ultrasonic transducers comprising a first ultrasonic transducer (2) and a second ultrasonic transducer (3), At least one third ultrasonic transducer (4), It has at least one ultrasonic transducer holder (5), the ultrasonic transducer holder (5) includes at least one ultrasonic transducer holder (5a, 5b), the at least one ultrasonic transducer holder (5) is positioned on a measuring tube (6) during operation, the measuring tube (6) has a measuring tube wall (8), a medium (12) is positioned inside the measuring tube (6) during operation, and in particular, during operation, the medium (12) flows through the measuring tube (12), The first ultrasonic transducer (2) and the second ultrasonic transducer (3) are arranged on the ultrasonic transducer holder (5), The first ultrasonic transducer (2) and the second ultrasonic transducer (3) form a measurement path (7) between them, extending through the ultrasonic transducer holder (5), the measuring tube wall (8), and the medium (12), so that a measurement signal transmitted from the first ultrasonic transducer (2) is received by the second ultrasonic transducer (3), and vice versa, and so that they are offset from each other in the direction of flow of the medium (12), in which case the measurement signal passes through three materials, namely the ultrasonic transducer holder (5), the measuring tube wall (8), and the medium (12). The third ultrasonic transducer (4) is positioned in the ultrasonic transducer holder (5) to define at least one first reference path (9) extending through the ultrasonic transducer holder (5), the measuring tube wall (8), and the medium (12), and the third ultrasonic transducer (4) is configured and positioned to receive and optionally transmit a reference signal propagating along the first reference path (9). A control and evaluation unit (11) is provided for controlling the ultrasonic transducers (2, 3, 4, 16) and for evaluating the signals received by the ultrasonic transducers (2, 3, 4, 16). In ultrasonic flow measuring device (1), The control and evaluation unit (11) is formed to carry out the method according to any one of claims 1 to 13, wherein the ultrasonic flow measuring device (1).

15. The ultrasonic flow rate measuring device (1) according to claim 14, characterized in that the third ultrasonic transducer (4) is arranged in the ultrasonic transducer holding device (5) such that the first reference path (9) extends perpendicular to the flow direction of the flowing medium (12).

16. The ultrasonic flow measuring device (1) according to claim 14 or 15, characterized in that the ultrasonic transducers (2, 3, 4, 16) are arranged such that a second reference path (13) exists through which a second reference signal propagates, and the second reference path (13) extends only inside the material of the ultrasonic transducer holder (5).

17. The ultrasonic flow measuring device (1) according to any one of claims 14 to 16, characterized in that a reflective element (14) for reflecting a second reference signal is formed inside the ultrasonic transducer holding device (5).

18. The ultrasonic flow measuring device (1) according to any one of claims 14 to 17, characterized in that the ultrasonic transducers (2, 3, 4, 16) are arranged on the at least one ultrasonic transducer holder (5) so as to be rigid, i.e., non-slidable, when viewed in the flow direction of the medium.

19. The ultrasonic flow measuring device (1) according to any one of claims 14 to 18, characterized in that it has a maximum of three or a maximum of four ultrasonic transducers (2, 3, 4, 16).

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