阅读说明：本技术 用于无创测量的换能器 (Transducer for non-invasive measurement ) 是由 C·伯恩哈德 F·卡苏贝克 M·伦纳 D·帕佩 于 2019-09-03 设计创作，主要内容包括：本发明涉及用于无创测量的换能器(10)。换能器包括至少一个第一压电元件(20)、第二压电元件(30)和基体材料(40)。基体材料配置成安装到配置成容纳液体的容器的壁(50)。基体材料包括平面部分(60)和角形部分(70)。角形部分包括多个外面(80)。角形部分的多个外面的第一面(90)连接到平面部分的第一面(100)。与平面部分的第一面相反的平面部分的第二面(110)配置成安装到容器的壁。角形部分的多个外面的至少一个第二面(120)在基体材料内部与角形部分的多个外面的第一面以比90度的角更小的角成角度。至少一个第一压电元件安装到角形部分的多个外面的至少一个第二面中的至少一个第二面。第二压电元件在与基体材料的角形部分相邻的位置处安装到基体材料的平面部分的第一面。(The invention relates to a transducer (10) for non-invasive measurement. The transducer comprises at least one first piezoelectric element (20), a second piezoelectric element (30) and a matrix material (40). The matrix material is configured to be mounted to a wall (50) of a container configured to contain a liquid. The base material includes a planar portion (60) and an angular portion (70). The angled portion includes a plurality of outer faces (80). A first face (90) of the plurality of outer faces of the angular portion is connected to a first face (100) of the planar portion. A second face (110) of the planar portion opposite the first face of the planar portion is configured to be mounted to a wall of the container. At least one second face (120) of the plurality of outer faces of the angled portion is angled at an angle less than 90 degrees from the first face of the plurality of outer faces of the angled portion within the base material. At least one first piezoelectric element is mounted to at least one of the at least one second faces of the plurality of outer faces of the angled portion. The second piezoelectric element is mounted to the first face of the planar portion of the base material at a position adjacent to the angular portion of the base material.)

1. A transducer (10) for non-invasive measurement, comprising:

at least one first piezoelectric element (20);

a second piezoelectric element (30); and

a base material (40);

wherein the matrix material is configured to be mounted to a wall (50) of a container containing a liquid;

wherein the base material comprises a planar portion (60) and an angular portion (70);

wherein the angled portion includes a plurality of outer faces (80);

wherein a first face (90) of the plurality of outer faces of the angular portion is connected to (or is part of) a first face (100) of the planar portion;

wherein a second face (110) of the planar portion opposite the first face of the planar portion is configured to be mounted to the wall of the container;

wherein at least one second face (120) of the plurality of outer faces of the angled portion is angled at an angle less than 90 degrees from the first face of the plurality of outer faces of the angled portion inside the base material;

wherein the at least one first piezoelectric element is mounted to at least one of the at least one second faces of the plurality of outer faces of the angled portion; and

wherein the second piezoelectric element is mounted to the first face of the planar portion of the base material at a position adjacent to the angular portion of the base material.

2. The transducer of claim 1, wherein a first one of the at least one second faces of the plurality of outer faces of the angled portion is angled at an angle greater than 90 degrees from a second one of the at least one second faces of the plurality of outer faces of the angled portion inside the base material.

3. The transducer of claim 2, wherein the first one of the at least one second faces of the plurality of outer faces of the angled portion is angled at an angle greater than 180 degrees from the second one of the at least one second faces of the plurality of outer faces of the angled portion inside the base material.

4. The transducer according to any of claims 2-3, wherein the first one of the at least one second faces of the plurality of outer faces of the angled portion is contiguous with the second one of the at least one second faces of the plurality of outer faces of the angled portion.

5. The transducer according to any of claims 2-4, wherein the first one of the at least one second of the plurality of outer faces of the angled portion is contiguous with the first of the plurality of outer faces of the angled portion.

6. The transducer according to any of claims 2-5, wherein a first one of the at least one first piezoelectric element is mounted to the first one of the at least one second outer faces of the angled portion and a second one of the at least one first piezoelectric element is mounted to the second one of the at least one second outer faces of the angled portion and/or wherein the first one of the at least one second outer faces of the angled portion is located on a side of the angled portion adjacent to where the second piezoelectric element is mounted to the planar portion.

7. The transducer of any of claims 2-6, wherein a third second face of the at least one second face of the plurality of outer faces of the angled portion is angled at an angle greater than 90 degrees from a fourth second face of the at least one second face of the plurality of outer faces of the angled portion inside the base material.

8. The transducer of claim 7, wherein the third one of the at least one second faces of the plurality of outer faces of the angled portion is angled at an angle greater than 180 degrees from the fourth one of the at least one second faces of the plurality of outer faces of the angled portion inside the base material.

9. The transducer according to any of claims 7-8, wherein the third one of the at least one second outer faces of the angled section is connected to the fourth one of the at least one second outer faces of the angled section, and/or wherein the third one of the at least one second outer faces of the angled section is connected to the first outer faces of the angled section.

10. The transducer according to any of claims 7-9, wherein a third one of the at least one first piezoelectric element is mounted to the third one of the at least one second plurality of outer faces of the angled portion, and/or wherein a fourth one of the at least one first piezoelectric element is mounted to the fourth one of the at least one second plurality of outer faces of the angled portion.

11. A non-invasive measurement method (200), comprising:

a) mounting (210) a base material to a wall of a container containing a liquid, wherein the base material comprises a planar portion and an angular portion, wherein the angular portion comprises a plurality of outer faces, wherein a first face of the plurality of outer faces of the angular portion is connected to a first face of the planar portion, wherein a second face of the planar portion, opposite the first face of the planar portion, is mounted to the wall of the container, wherein at least one second face of the plurality of outer faces of the angular portion is angled inside the base material at an angle smaller than 90 degrees from the first face of the plurality of outer faces of the angular portion, wherein at least one first piezoelectric element is mounted to at least one second face of the plurality of outer faces of the angular portion; and wherein a second piezoelectric element is mounted to the first face of the planar portion of the base material at a position adjacent to the angular portion of the base material; and

b) activating (220) the at least one first piezoelectric element and the second piezoelectric element.

12. A transducer system (300) for non-invasive measurements, comprising:

at least one first piezoelectric element (310)

A second piezoelectric element (320); and

a base material (330);

wherein the base material comprises a plurality of outer faces (340);

wherein a first face (350) of the plurality of outer faces is mounted to a wall (360) of a container containing a liquid;

wherein at least one second face (370) of the plurality of outer faces is angled from the first face at an angle less than 90 degrees inside the matrix material;

wherein the at least one first piezoelectric element is mounted to at least one of the at least one second face; and

wherein the second piezoelectric element is mounted to the wall of the container at a location adjacent to the base material.

13. The transducer according to claim 12, wherein the second piezoelectric element is mounted to the wall of the container via an intermediate planar base material (380), wherein the second piezoelectric element is mounted to a first surface (390) of the planar base material and a second face (395) of the planar base material parallel to the first surface of the planar base material is mounted to the wall of the container.

14. The transducer system according to any of claims 12-13, wherein a first one of the at least one second face is angled at an angle larger than an angle of 90 degrees with a second one of the at least one second face inside the base material, and/or wherein the first one of the at least one second face is angled at an angle larger than an angle of 180 degrees with the second one of the at least one second face inside the base material.

15. A non-invasive measurement method (400), comprising:

a) mounting (410) a matrix material to a wall of a container containing a liquid, wherein the matrix material comprises a plurality of outer faces, wherein a first face of the plurality of outer faces is mounted to the wall of the container, wherein at least one second face of the plurality of outer faces is angled from the first face at an angle less than 90 degrees inside the matrix material, and wherein at least one first piezoelectric element is mounted to at least one of the at least one second face;

b) mounting (420) a second piezoelectric element to the wall of the container at a location adjacent to the base material; and

c) activating (430) the at least one first piezoelectric element and the second piezoelectric element.

Technical Field

The present invention relates to a transducer for non-invasive measurement, in particular an ultrasound transducer, and an associated non-invasive measurement method, a transducer system for non-invasive measurement, and an associated non-invasive measurement method.

Background

Industrial applications using acoustic techniques, including non-destructive testing, non-invasive flow or level (level) measurements, require a special type of ultrasonic transducer that emits sound waves into the surrounding medium over a large angular range. In particular, for level measurement applications, the sensor must be able to cover a certain span of angles, typically in the range between 0 and 70 ° with respect to the normal of the tank (tank) surface. These requirements cannot be met by using a single piezoelectric element. Therefore, in order to achieve a sufficiently large radiation angle range, piezoelectric phased arrays driven by phase-shifting electrical signals are generally employed — see US4692654A, WO2016134005a1 and EP0264991a 1. High quality acoustic beams exhibiting low divergence in suppressed side lobes require a large number of piezoelectric elements (or special bulk piezoelectric designs) and complex and thus expensive drive electronics to generate signals with variable phase and amplitude. The electrical connections between the drive electronics and the piezoelectric array need to be shielded and isolated, which requires special wiring techniques and is therefore costly in view of the large number of components. Another transducer type is represented by wedge-based transducers that emit Lamb waves — see "Mode and transducer selection for long-range membrane wave actuation" by p.d. Wilcox et al, j.int. mat. syst. struct.12553 (2001) and EP1111351a2, whose range of radiation angles is controlled by the ratio of the speed of sound of the (Lamb) wave in the wall to the speed of sound in the medium to be demonstrated. For example, the radiation angle from a steel wall into the water can be about 30 ° relative to the wall normal. The radiation angle of a transducer emitting longitudinal (direct) sound waves is usually perpendicular to the wall, however, the radiation angle is not controllable.

There are improved techniques for providing non-invasive measurements that allow control of the angle of emission into the liquid over a large angular range.

Disclosure of Invention

It would therefore be advantageous to have an improved transducer for non-invasive measurements and an improved method of non-invasive measurements.

The object of the invention is solved with the subject matter of the independent claims, wherein further embodiments are incorporated in the dependent claims. It should be noted that the below described aspects of the invention are also applicable to transducers for non-invasive measurements, transducer systems for non-invasive measurements and to non-invasive measurement methods.

In a first aspect, there is provided a transducer for non-invasive measurement, the transducer comprising:

-at least one first piezoelectric element;

-a second piezoelectric element; and

-a matrix material.

The matrix material is configured to be mounted to a wall of a container configured to contain a liquid. The term "container" is used herein and throughout this document in a broad sense, not limited to a closed reservoir (container), but also includes an at least partially open reservoir, and also includes a tube or pipe or line configured to contain or conduct any kind of medium, such as all kinds of liquids, liquefied solids or gases.

The base material includes a planar portion and an angular portion. The angled portion includes a plurality of outer faces. A first face of the plurality of outer faces of the angular portion is connected to a first face of the planar portion. A second face of the planar portion opposite the first face of the planar portion is configured to be mounted to a wall of the container. At least one second face of the plurality of outer faces of the angled portion is angled at an angle less than 90 degrees from the first face of the plurality of outer faces of the angled portion within the base material. At least one first piezoelectric element is mounted to at least one of the at least one second faces of the plurality of outer faces of the angled portion. The second piezoelectric element is mounted to the first face of the planar portion of the base material at a position adjacent to the angular portion of the base material.

In other words, a number of piezoelectric emitters are mounted to a unitary base element, and the angles and parameters of the emitters are optimized according to the radiation required in the liquid to be detected. The emitters mounted in the planar orientation are primarily intended to emit waves close to the normal of the vessel wall, while additional emitters are mounted on the angled portions of the matrix material, said additional emitters being intended to excite waves radiated at angles closer to the tangential direction. The angled portion can be formed by different wedge-shaped sections that can be optimized for different radiation angles. In this way, a total angular range is provided. Thus, discrete piezoelectric element emitters are used to provide a particular arrangement for achieving a large span of radiation angles. This combines the following: (i) the piezoelectric emitters are oriented parallel or at an oblique angle ("wedge") with respect to the wall surface; (ii) using different sizes and shapes of piezoelectric emitters; (iii) different acoustic modes (excited at different frequencies) using piezoelectric emitters; (iv) changing the position of a piezoelectric element on the transducer substrate; (v) the transducer base material is selected. In this description, transmission of a signal is described. Due to the linearity of the system, there is an interaction of the nature of the transmission and reception of the signals-therefore a good transmitter is also a good receiver for the corresponding signal. Thus, the present invention incorporates a system for launching into and receiving from a liquid.

In other words, a special arrangement of emitters is utilized, wherein individually operated emitters are fixed to a single unitary base element at a specific mounting angle. The angle and piezoelectric parameters are optimized according to the required radiation angle range. The transmission process (direct wave and/or lamb wave) and the corresponding transmission mode can be selected by switching between the different transmitters and operating them in the appropriate frequency range. A compact transducer design is provided as follows: using simple electronics, providing improved efficiency, having high design flexibility, and providing high robustness and reliability.

In an example, a first one of the plurality of outer at least one second faces of the angled portion is angled at an angle greater than 90 degrees with a second one of the plurality of outer at least one second faces of the angled portion inside the base material.

In an example, a first one of the plurality of outer at least one second faces of the angled portion is angled at an angle greater than 180 degrees from a second one of the plurality of outer at least one second faces of the angled portion within the base material.

In an example, a first one of the plurality of outer at least one second faces of the angled portion is connected to a second one of the plurality of outer at least one second faces of the angled portion.

In an example, a first one of the at least one second plurality of outer faces of the angled portion is connected to the first plurality of outer faces of the angled portion.

In an example, a first one of the at least one first piezoelectric element is mounted to a first one of the at least one second outer faces of the angled portion, and a second one of the at least one first piezoelectric element is mounted to a second one of the at least one second outer faces of the angled portion.

In an example, a first one of the at least one outer second faces of the angled portion is located on a side of the angled portion adjacent to where the second piezoelectric element is mounted to the planar portion.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is angled at an angle greater than 90 degrees from a fourth one of the at least one second plurality of outer faces of the angled portion inside the base material.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is angled at an angle greater than 180 degrees from a fourth one of the at least one second plurality of outer faces of the angled portion inside the base material.

In an example, a third one of the plurality of outer at least one second faces of the angled portion is connected to a fourth one of the plurality of outer at least one second faces of the angled portion.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is connected to the first plurality of outer faces of the angled portion.

In an example, a third one of the at least one first piezoelectric element is mounted to a third one of the at least one second faces of the plurality of outer faces of the angled portion.

In an example, a fourth one of the at least one first piezoelectric element is mounted to a fourth one of the at least one second faces of the plurality of outer faces of the angled portion.

In a second aspect, there is provided a non-invasive measurement method comprising:

a) mounting a base material to a wall of a container containing a liquid, wherein the base material comprises a planar portion and an angled portion, wherein the angled portion comprises a plurality of outer faces, wherein a first face of the plurality of outer faces of the angled portion is connected to a first face of the planar portion, wherein a second face of the planar portion, opposite the first face of the planar portion, is mounted to the wall of the container, wherein at least one second face of the plurality of outer faces of the angled portion is angled at an angle less than 90 degrees from the first face of the plurality of outer faces of the angled portion inside the base material, wherein at least one first piezoelectric element is mounted to at least one second face of the plurality of outer faces of the angled portion; and wherein the second piezoelectric element is mounted to the first face of the planar portion of the base material at a position adjacent to the angular portion of the base material; and

b) at least one first piezoelectric element and one second piezoelectric element are activated (220).

In a third aspect, there is provided a transducer system for non-invasive measurement, the transducer system comprising:

-at least one first piezoelectric element (310);

-a second piezoelectric element (320); and

-a matrix material (330).

The matrix material includes a plurality of outer faces. A first face of the plurality of outer faces is mounted to a wall of a container configured to hold a liquid. At least one second face of the plurality of outer faces is angled from the first face at an angle less than 90 degrees inside the matrix material. At least one first piezoelectric element is mounted to at least one of the at least one second faces. A second piezoelectric element is mounted to the wall of the container at a location adjacent the matrix material.

In other words, the piezoelectric emitter mounted to the planar portion can also be mounted to the wall of the container as a separate unit, rather than having a base material with a planar portion and an angled portion, where the piezoelectric emitter is mounted to the planar portion (and to the angled portion). In addition, the piezoelectric transmitter can be mounted directly to the wall or via a separate planar base material. This allows greater flexibility with respect to the precise mounting location of the piezoelectric transmitter.

In an example, the second piezoelectric element is mounted to a wall of the container via an intermediate planar matrix material. The second piezoelectric element is mounted to a first surface of the planar base material, and a second surface of the planar base material parallel to the first surface of the planar base material is mounted to a wall of the container.

In an example, a first one of the at least one second face is angled at an angle greater than 90 degrees from a second one of the at least one second face inside the matrix material.

In an example, a first one of the at least one second face is angled at an angle greater than 180 degrees from a second one of the at least one second face inside the matrix material.

In an example, a first one of the at least one second face is connected to a second one of the at least one second face.

In an example, a first one of the at least one second face is connected to the first face.

In an example, a first one of the at least one first piezoelectric element is mounted to a first one of the at least one second face and a second one of the at least one first piezoelectric element is mounted to a second one of the at least one second face.

In an example, a first one of the at least one outer second faces of the angled portion is located on a side of the angled portion adjacent to where the second piezoelectric element is mounted to the planar portion.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is angled at an angle greater than 90 degrees from a fourth one of the at least one second plurality of outer faces of the angled portion inside the base material.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is angled at an angle greater than 180 degrees from a fourth one of the at least one second plurality of outer faces of the angled portion inside the base material.

In an example, a third one of the plurality of outer at least one second faces of the angled portion is connected to a fourth one of the plurality of outer at least one second faces of the angled portion.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is connected to the first plurality of outer faces of the angled portion.

In an example, a third one of the at least one first piezoelectric element is mounted to a third one of the at least one second faces of the plurality of outer faces of the angled portion.

In an example, a fourth one of the at least one first piezoelectric element is mounted to a fourth one of the at least one second faces of the plurality of outer faces of the angled portion.

In a fourth aspect, there is provided a non-invasive measurement method including:

a) mounting a base material to a wall of a vessel containing a liquid, wherein the base material comprises a plurality of outer faces, wherein a first face of the plurality of outer faces is mounted to the wall of the vessel, wherein at least one second face of the plurality of outer faces is angled from the first face at an angle less than 90 degrees inside the base material, and wherein at least one first piezoelectric element is mounted to at least one of the at least one second face;

b) mounting a second piezoelectric element to a wall of the container at a location adjacent to the matrix material; and

c) at least one first piezoelectric element and one second piezoelectric element are activated.

The aspects and examples hereinbefore will be apparent from and elucidated with reference to the embodiments described hereinafter.

Drawings

Exemplary embodiments will be described hereinafter with reference to the following drawings:

fig. 1 shows a schematic representation of a transducer for non-invasive measurement;

fig. 2 shows a non-invasive measurement method;

FIG. 3 shows a schematic representation of a transducer system for non-invasive measurement;

FIG. 4 illustrates a non-invasive measurement method;

FIG. 5 shows an example of the transducer of FIG. 1;

FIG. 6 shows an example of the transducer of FIG. 1; and

fig. 7 shows an example of the transducer of fig. 1.

Detailed Description

Fig. 1 shows an example of a transducer 10 for non-invasive measurement. The transducer comprises at least one first piezoelectric element 20, a second piezoelectric element 30 and a matrix material 40. The matrix material is configured to be mounted to a wall 50 of a container configured to contain a liquid.

The term "container" is used here and throughout this document in a broad sense, not limited to a closed reservoir, but also includes an at least partially open reservoir, and also includes a tube or pipe (plumbig) or a pipeline configured to contain or guide any kind of medium, such as all kinds of liquids, liquefied solids or gases.

The base material includes a planar portion 60 and an angular portion 70. The angled portion includes a plurality of outer faces 80. In the exemplary embodiment shown here, the first face 90 of the plurality of outer faces of the angled portion is connected to (or joined to) the first face 100 of the planar portion. Typically, the angled portion and the planar portion physically form the same unit. Typically, the angled and planar portions are made from the same piece of material, i.e., there are possible embodiments in which such "joining" is not required. A second face 110 of the planar portion, opposite the first face of the planar portion, is configured to be mounted to a wall of the container. At least one second face 120 of the plurality of outer faces of the angled portion is angled at an angle less than 90 degrees from the first face of the plurality of outer faces of the angled portion within the base material. At least one first piezoelectric element is mounted to at least one of the at least one second faces of the plurality of outer faces of the angled portion. The second piezoelectric element is mounted to the first face of the planar portion of the base material at a position adjacent to the angular portion of the base material.

In other words, the following are set: the transducer body with the face(s) is aligned with a direction perpendicular to the measurement direction. The normal to the walls of these faces is between 0 (planar case) and <90 degrees. Piezoelectric elements that are generating an ultrasound beam are mounted on these faces. The system has at least two different sides (phases) with different angles and possibly different distances between the piezo element and the wall, allowing different radiation patterns to be generated in the liquid.

In examples, various shapes of designs can be provided: a) simple (fig. 5); b) a cap (fig. 6); and c) a tent (fig. 7).

According to an example, a first one of the plurality of outer at least one second faces of the angled portion is angled at an angle greater than 90 degrees with a second one of the plurality of outer at least one second faces of the angled portion inside the base material.

According to an example, a first one of the plurality of outer at least one second faces of the angled portion is angled at an angle greater than 180 degrees with a second one of the plurality of outer at least one second faces of the angled portion inside the base material.

According to an example, a first one of the plurality of outer at least one second faces of the angled portion is connected to a second one of the plurality of outer at least one second faces of the angled portion.

According to an example, a first one of the at least one second plurality of outer faces of the angled portion is connected to the first plurality of outer faces of the angled portion.

According to an example, a first one of the at least one first piezoelectric element is mounted to a first one of the at least one second outer faces of the angled portion, and a second one of the at least one first piezoelectric element is mounted to a second one of the at least one second outer faces of the angled portion.

According to an example, a first one of the at least one outer second faces of the angled portion is located on a side of the angled portion adjacent to where the second piezoelectric element is mounted to the planar portion.

According to an example, a third second face of the plurality of outer faces of the angled portion is angled at an angle greater than 90 degrees from a fourth second face of the plurality of outer faces of the angled portion inside the base material.

According to an example, a third second face of the plurality of outer faces of the angled portion is angled at an angle greater than 180 degrees from a fourth second face of the plurality of outer faces of the angled portion inside the base material.

According to an example, a third one of the plurality of outer at least one second faces of the angled portion is connected to a fourth one of the plurality of outer at least one second faces of the angled portion.

According to an example, a third one of the at least one second plurality of outer faces of the angled portion is connected to the first plurality of outer faces of the angled portion.

According to an example, a third one of the at least one first piezoelectric element is mounted to a third one of the at least one second faces of the plurality of outer faces of the angled portion.

According to an example, a fourth one of the at least one first piezoelectric element is mounted to a fourth one of the at least one second faces of the plurality of outer faces of the angled portion.

Fig. 2 shows a non-invasive measurement method 200, the non-invasive measurement method 200 comprising:

in a mounting step 210 (which is also referred to as step a)), mounting a base material to a wall of a container containing a liquid, wherein the base material comprises a planar portion and an angular portion, wherein the angular portion comprises a plurality of outer faces, wherein a first face of the plurality of outer faces of the angular portion is connected to a first face of the planar portion or is physically part of the first face of the planar portion, wherein a second face of the planar portion opposite the first face of the planar portion is mounted to the wall of the container, wherein at least one second face of the plurality of outer faces of the angular portion is angled inside the base material at an angle smaller than 90 degrees from the first face of the plurality of outer faces of the angular portion, wherein at least one first piezoelectric element is mounted to at least one second face of the plurality of outer faces of the angular portion; and wherein the second piezoelectric element is mounted to the first face of the planar portion of the base material at a position adjacent to the angular portion of the base material; and

in an activation step 220, which is also referred to as step b), at least one of the piezoelectric elements is activated.

In an example, a first one of the plurality of outer at least one second faces of the angled portion is angled at an angle greater than 90 degrees with a second one of the plurality of outer at least one second faces of the angled portion inside the base material.

In an example, a first one of the plurality of outer at least one second faces of the angled portion is angled at an angle greater than 180 degrees from a second one of the plurality of outer at least one second faces of the angled portion within the base material.

In an example, a first one of the plurality of outer at least one second faces of the angled portion is connected to a second one of the plurality of outer at least one second faces of the angled portion.

In an example, a first one of the at least one second plurality of outer faces of the angled portion is connected to the first plurality of outer faces of the angled portion.

In an example, a first one of the at least one first piezoelectric element is mounted to a first one of the at least one second outer faces of the angled portion and a second one of the at least one first piezoelectric element is mounted to a second one of the at least one second outer faces of the angled portion.

In an example, a first one of the at least one outer second faces of the angled portion is located on a side of the angled portion adjacent to where the second piezoelectric element is mounted to the planar portion.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is angled at an angle greater than 90 degrees from a fourth one of the at least one second plurality of outer faces of the angled portion inside the base material.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is angled at an angle greater than 180 degrees from a fourth one of the at least one second plurality of outer faces of the angled portion inside the base material.

In an example, a third one of the plurality of outer at least one second faces of the angled portion is connected to a fourth one of the plurality of outer at least one second faces of the angled portion.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is connected to the first plurality of outer faces of the angled portion.

In an example, a third one of the at least one first piezoelectric element is mounted to a third one of the at least one second faces of the plurality of outer faces of the angled portion.

In an example, a fourth one of the at least one first piezoelectric element is mounted to a fourth one of the at least one second faces of the plurality of outer faces of the angled portion.

Fig. 3 shows an example of a transducer system 300 for non-invasive measurement. The transducer system comprises at least one first piezoelectric element 310, a second piezoelectric element 320 and a matrix material. The base material includes a plurality of outer faces 340. The plurality of outer first faces 350 are mounted to a wall 360 of a container configured to hold a liquid. At least one second face 370 of the plurality of outer faces is angled from the first face at an angle less than 90 degrees inside the matrix material. At least one first piezoelectric element is mounted to at least one of the at least one second faces. A second piezoelectric element is mounted to the wall of the container at a location adjacent the matrix material.

According to an example, the second piezoelectric element is mounted to the wall of the container via an intermediate planar matrix material 380, wherein the second piezoelectric element is mounted to a first surface 390 of the planar matrix material and a second face 395 of the planar matrix material parallel to the first surface of the planar matrix material is mounted to the wall of the container.

According to an example, a first one of the at least one second face is angled inside the matrix material at an angle larger than an angle of 90 degrees with a second one of the at least one second face.

According to an example, a first one of the at least one second face is angled inside the matrix material with a second one of the at least one second face at an angle larger than an angle of 180 degrees.

According to an example, a first one of the at least one second face is connected to a second one of the at least one second face.

According to an example, a first one of the at least one second face is connected to the first face.

According to an example, a first one of the at least one first piezoelectric element is mounted to a first one of the at least one second face and a second one of the at least one first piezoelectric element is mounted to a second one of the at least one second face.

According to an example, a first one of the at least one outer second faces of the angled portion is located on a side of the angled portion adjacent to where the second piezoelectric element is mounted to the planar portion.

According to an example, a third second face of the plurality of outer faces of the angled portion is angled at an angle greater than 90 degrees from a fourth second face of the plurality of outer faces of the angled portion inside the base material.

According to an example, a third second face of the plurality of outer faces of the angled portion is angled at an angle greater than 180 degrees from a fourth second face of the plurality of outer faces of the angled portion inside the base material.

According to an example, a third one of the plurality of outer at least one second faces of the angled portion is connected to a fourth one of the plurality of outer at least one second faces of the angled portion.

According to an example, a third one of the at least one second plurality of outer faces of the angled portion is connected to the first plurality of outer faces of the angled portion.

According to an example, a third one of the at least one first piezoelectric element is mounted to a third one of the at least one second faces of the plurality of outer faces of the angled portion.

According to an example, a fourth one of the at least one first piezoelectric element is mounted to a fourth one of the at least one second faces of the plurality of outer faces of the angled portion.

Fig. 4 illustrates a non-invasive measurement method 400, the non-invasive measurement method 400 comprising:

in a mounting step 410 (which is also referred to as step a)), mounting a matrix material to a wall of a vessel containing the liquid, wherein the matrix material comprises a plurality of outer faces, wherein a first face of the plurality of outer faces is mounted to the wall of the vessel, wherein at least one second face of the plurality of outer faces is angled from the first face at an angle smaller than 90 degrees inside the matrix material, and wherein at least one first piezoelectric element is mounted to at least one second face of the at least one second face;

in a mounting step 420 (which is also referred to as step b)), mounting a second piezoelectric element to a wall of the container at a position adjacent to the matrix material; and

in an activation step 430 (which is also referred to as step c)), at least one first piezoelectric element and one second piezoelectric element are activated.

In an example, a first one of the at least one second face is angled at an angle greater than 90 degrees from a second one of the at least one second face inside the matrix material.

In an example, a first one of the at least one second face is angled at an angle greater than 180 degrees from a second one of the at least one second face inside the matrix material.

In an example, a first one of the at least one second face is connected to a second one of the at least one second face.

In an example, a first one of the at least one second face is connected to the first face.

In an example, a first one of the at least one first piezoelectric element is mounted to a first one of the at least one second face and a second one of the at least one first piezoelectric element is mounted to a second one of the at least one second face.

In an example, a first one of the at least one outer second faces of the angled portion is located on a side of the angled portion adjacent to where the second piezoelectric element is mounted to the planar portion.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is angled at an angle greater than 90 degrees from a fourth one of the at least one second plurality of outer faces of the angled portion inside the base material.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is angled at an angle greater than 180 degrees from a fourth one of the at least one second plurality of outer faces of the angled portion inside the base material.

In an example, a third one of the plurality of outer at least one second faces of the angled portion is connected to a fourth one of the plurality of outer at least one second faces of the angled portion.

In an example, a third one of the at least one second plurality of outer faces of the angled portion is connected to the first plurality of outer faces of the angled portion.

In an example, a third one of the at least one first piezoelectric element is mounted to a third one of the at least one second faces of the plurality of outer faces of the angled portion.

In an example, a fourth one of the at least one first piezoelectric element is mounted to a fourth one of the at least one second faces of the plurality of outer faces of the angled portion.

The transducer and the non-invasive measurement method for non-invasive measurement will now be described in more detail with reference to fig. 5-7.

Fig. 5 shows a simple combined transducer design, which is a detailed example of the transducer shown in fig. 1. Fig. 6 shows a cap transducer design, which is a detailed example of the transducer shown in fig. 1. Fig. 7 illustrates a tent transducer design, which is a detailed example of the transducer shown in fig. 1. In all three figures, the corresponding angular range of sound radiation is shown. For these transducers, a number of discrete piezoelectric elements are placed on a single unitary transducer base element. Individually operated emitters generate transverse or longitudinal waves that are emitted over a range of angles and produce different emission cones in the medium. The transducer is mounted to a wall of a vessel containing a medium (e.g., a liquid not shown in these figures). The combination of all cones of radiation produced by the individual emitters accounts for the total angular span of the transducer. The emitter(s) placed or mounted on the planar portion of the base material are primarily used for the transmission of longitudinal (or direct) waves. However, as detailed in the description associated with fig. 3-4, the planar portion need not be part of a unitary base element and can be separately mounted to the container wall via an intermediate separate base material, if necessary. Also, although in the general discussion only one emitter is described as being mounted on a planar portion of the base material, more than one emitter can be mounted to a planar portion of the base material, or more than one emitter can be individually mounted to an angled base material. With continued reference to the planar mounted transmitter shown in fig. 5-7, the piezoelectric transmitter is preferably operated at its thickness resonance to generate longitudinal waves that propagate through the backplane and excite acoustic waves in the surrounding medium. These waves propagate (close) normal to the vessel wall.

The emitter(s) mounted on the wedge-shaped portion of the matrix material are used for excitation of lamb modes in order to excite acoustic waves in the liquid in the range of angles of about 30 ° to 90 ° with respect to the wall normal — these angles for leaky lamb waves (due to the dispersion of lamb waves) depend on the frequency. The optimum coupling angle (the angle of the incoming ray on the transducer side relative to the wall normal) is determined by the propagation velocity of the lamb mode in the wall and the speed of sound in the matrix material. The coupling angle is therefore chosen such that it satisfies this condition for the frequency corresponding to the desired emission angle into the liquid. If the desired angle is changed, a different coupling angle, and thus the angular orientation of the emitting face, must be chosen, which is why it may be necessary to also use a plurality of piezoelectric elements to cover the angular region to be covered by the lamb wave emission.

In other words, different piezoelectric elements emitting from different sides encompass different angular ranges. By a clever combination of piezoelectric element type and angle, one piezoelectric element can cover the entire angular range.

The distance between the emitter and the wall determines the size of the surface on the wall to be illuminated and allows control of the beam divergence. For the selection of the matrix material, two criteria must be met: a) the acoustic velocity of the appropriate acoustic mode (longitudinal or transverse) must be lower than that of the medium; and b) the acoustic damping should be high enough to avoid unwanted acoustic radiation due to internal reflections. The skilled person will be aware of suitable materials.

Having several piezoelectric elements on the transducer base allows the following additional functions: a) determining the transducer internal propagation time, which yields improved measurement accuracy results; b) redundant level measurement is performed using a number of piezoelectric elements; and c) a functional check of the system, which yields a result of improved reliability.

It has to be noted that embodiments of the invention are described with reference to different subject matters. In particular, some embodiments are described with reference to method type claims whereas other embodiments are described with reference to apparatus type claims. However, a person skilled in the art will gather from the above and the following description that, unless other notified, in addition to any combination of features belonging to one type of subject-matter also any combination between features relating to different subject-matters is considered to be disclosed with this application. However, all features can be combined, providing synergy over a simple summary of features.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims shall not be construed as limiting the scope.