Device and method for monitoring a medium

Abstract

The invention discloses a device (1) for monitoring a medium (2, 2') in a container (3). An electrode unit (10) can be attached to a wall (30) of the container (3) and has several sensor electrodes (100) arranged along a longitudinal axis (101). A control device (11) supplies the electrode unit (10) with query signals, which are electrical signals with predefinable frequencies. The control device (11) receives response signals and evaluates them by relating the response signals corresponding to query signals with different frequencies to one another and evaluating the results of this relation to determine the state of the medium (2, 2') in the container (3). Furthermore, the invention relates to a method for monitoring a medium (2, 2').

Description

[0001] The invention relates to a device for monitoring a medium in a container. The invention further relates to a method for monitoring a medium in a container.

[0002] It is known in the art to determine the fill level of a medium in a container capacitively. The capacitor required for this purpose consists of an electrode attached to the container at a known height and the medium acting as a dielectric. To measure the capacitance or impedance, an alternating voltage signal is applied to the electrode. A change in capacitance then indicates that the fill level associated with the electrode has either been exceeded or fallen below. This is therefore a method for monitoring a limit level of a medium within a container.

[0003] It is also known in the prior art to attach an electrode to the container in such a way that it extends vertically and therefore allows continuous level measurement (see, for example, DE 10 2010 030 362 A1). It is also known to place several electrodes at different heights and thus detect the level in discrete steps (see, for example, DE 10 2020 109 699 A1). WO 2023 / 069400 A1 discloses the process of placing a capacitive sensor at different heights on a container with a medium.

[0004] DE 20 2011 107 423 U1 discloses a single sensor electrode that can be attached to the wall of a container and enables foam detection. However, it does not disclose how a distinction is made between a medium and foam.

[0005] Detecting foam formation can be important for monitoring biochemical processes, such as fermentation. Foam detection is also important, for example, during bottling processes.

[0006] The invention is based on the objective of enabling a differentiation between different states of a medium.

[0007] The invention solves the problem by a device for monitoring a medium in a container, comprising at least one electrode unit and a control device, wherein the electrode unit can be attached to a wall of the container, wherein the electrode unit has several sensor electrodes, wherein the sensor electrodes are arranged along a longitudinal axis of the electrode unit, wherein the control device supplies the electrode unit with query signals, wherein the query signals are electrical signals with predefinable frequencies, wherein the control device receives response signals from the electrode unit, and wherein the control device evaluates the received response signals and / or dependent data by assigning those response signals to query signals with different frequencies.and / or relates dependent data to each other and generates relation results and evaluates the relation results to determine the state of the medium in the container.

[0008] In the device according to the invention, the control device supplies the electrode unit with electrical signals as query signals, each having predefinable frequencies. In one embodiment, the electrical signals are alternating voltage signals. In an alternative embodiment, they are pulsed direct voltage.

[0009] The electrode unit, and thus its sensor electrodes, are preferably attached to a wall of the container during the measurement. The longitudinal axis of the electrode unit is preferably aligned along the height of the container, so that the sensor electrodes are located at different heights within the container. For evaluation purposes, it is preferably known which heights each sensor electrode corresponds to.

[0010] The control device receives response signals from the electrode unit, which are assigned to the query signals, and evaluates them and / or dependent data accordingly. In one embodiment, the evaluation of the response signals preferably also includes the evaluation of signals that depend on the response signals. During the evaluation, the control device relates those response signals (or dependent signals or data) to each other that are assigned to query signals with different frequencies. The control device generates relational results, which it evaluates to determine the state of the medium in the container. Thus, during the evaluation, response signals belonging to query signals with different frequencies are linked together. For example, one response signal is obtained at 1 MHz and another at 10 MHz.

[0011] In one embodiment, the control device determines an impedance value and / or a capacitance value from the received response signals as data dependent on the response signals. For establishing the relationship, the difference or a quotient of the determined capacitance or impedance values ​​at the different frequencies of the query signal is calculated, for example.

[0012] The results of the relations, such as differences or quotients, then allow the determination of the state of the medium in the container.

[0013] One embodiment involves the control device evaluating the relation results to determine the fill level and state of the medium within the container. This embodiment thus determines not only the state of the medium but also its state within a specific area.

[0014] Consider, for example, a liquid that tends to foam. With this medium, it can be determined whether it exists as a liquid or as foam. Thus, it is possible, in particular, to detect whether foam has formed. In one embodiment, the device according to the invention is therefore a foam detector. Accordingly, in one embodiment, the evaluation of the results is reduced to identifying the presence of foam. In the aforementioned embodiment, the device additionally determines the fill level of the liquid and the fill level of the foam.

[0015] In one embodiment of the invention, by relating the signals or associated data to each other, calibration of the device is dispensed with.

[0016] In one embodiment, the results of the measurements assigned to the individual sensor electrodes are compared to determine the state of the medium at each sensor electrode. Significant changes, i.e., jumps, are identified and evaluated as indicators of the fill level.

[0017] One embodiment of the device involves attaching the electrode unit to the wall of the container. The electrode unit is preferably aligned on the wall such that the sensor electrodes are located at different heights within the container. In one embodiment, the attachment is achieved by adhesive. In an alternative and / or supplementary embodiment, the attachment is reversible, allowing the electrode unit to be removed.

[0018] One embodiment of the device provides that, during evaluation, the control device relates the response signals assigned to query signals with different frequencies and each associated with a sensor electrode, and / or dependent data, to one another and generates the relational results. In this embodiment, the response signals are related to each other with respect to a specific sensor electrode. Thus, the response signals generated with different frequencies of the query signal, each belonging to a specific sensor electrode, are compared to one another. This results in at least one relational result for each sensor electrode if at least two different frequencies have been set for the query signals. In one embodiment, the relational results are compared to obtain the desired data on the state and, if applicable, the fill level of the liquid.

[0019] Furthermore, the invention solves the problem by a method for monitoring a medium in a container, wherein the method comprises at least the following steps: attaching several sensor electrodes to a wall of the container; supplying the sensor electrodes with interrogation signals, wherein the interrogation signals are electrical signals with predefinable frequencies; receiving response signals; relating the response signals that are assigned to interrogation signals with different frequencies and / or dependent data to each other and generating relational results; and evaluating the relational results to determine the state of the medium in the container. The preceding and following embodiments of the device also apply accordingly to the method, so repetition is omitted.Conversely, the variations of the procedure and the explanations apply appropriately to the device.

[0020] One embodiment of the method involves relating response signals, which are assigned to query signals with different frequencies and each associated with a sensor electrode, and / or dependent data, to one another and generating relational results. In this embodiment, response signals belonging to the same sensor electrode but with different frequencies of the query signals, and / or dependent data or signals, are related to one another to obtain relational results for further analysis. Depending on the embodiment, the relational results can be quotients, differences, or combinations thereof.

[0021] The invention is explained in more detail with reference to the following figure. Fig. Figure 1 schematically shows a measurement setup.

[0022] The Fig. Figure 1 shows a container 3, on the outside of whose wall 30 the electrode unit 10 of the measuring device 1 is attached.

[0023] The electrode unit 10 has seven sensor electrodes 100 arranged along the longitudinal axis 101. The longitudinal axis 101 runs parallel to the longitudinal axis of the container 3, so that each sensor electrode 100 is assigned a height within the container 3 and the length of the electrode unit 10 is optimally utilized for the measurement.

[0024] The control device 11 is connected to the electrode unit 10 in such a way that the sensor electrodes 100 can be supplied with the query signals from the control device 11. Furthermore, the connection is such that the control device 11 receives the resulting response signals individually from the sensor electrodes 100. Alternatively, the response signals are encoded to identify which sensor electrode 100 they originate from. The control device 11 has, in particular, the information about which query signal the response signals are assigned to. This specifically refers to the frequency of the respective query signal.

[0025] Based on the information about the assigned query signals and the sensor electrode 100, the control device 11 evaluates the response signals. This relates in particular to the establishment of a relationship.

[0026] Based on the results of the relationship, the control device 11 in the illustrated example can determine that the medium in liquid form 2 extends here to the fourth sensor electrode 100 and as foam 2' to the sixth sensor electrode 100. The seventh sensor electrode 100 indicates that no medium and therefore only air is present at its level. Reference symbol list 1 device 2 Medium 2' Medium 3 containers 10 electrode units 11 Control device 30 Wall of the container 100 sensor electrodes 101 Longitudinal axis of the electrode unit QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2010 030 362 A1

[0003] DE 10 2020 109 699 A1

[0003] WO 2023 / 069400 A1

[0003] DE 20 2011 107 423 U1

[0004]

Claims

[1] Device (1) for monitoring a medium (2, 2') in a container (3), with at least one electrode unit (10) and a control device (11), wherein the electrode unit (10) can be fastened to a wall (30) of the container (3), wherein the electrode unit (10) comprises a plurality of sensor electrodes (100), wherein the sensor electrodes (100) are arranged along a longitudinal axis (101) of the electrode unit (10), wherein the control device (11) supplies the electrode unit (10) with interrogation signals, where the query signals are electrical signals with predeterminable frequencies, wherein the control device (11) receives response signals from the electrode unit (10), and wherein the control device (11) evaluates the received response signals and / or data dependent thereon, in that the control device (11) relates those response signals which are assigned to query signals with different frequencies and / or data dependent thereon to one another and generates relation results and evaluates the relation results to determine which state form the medium (2, 2') has in the container (3). [2] Device (1) according to claim 1, wherein the control device (11) evaluates the relation results to determine which fill level the medium (2, 2') has in which state in the container (3). [3] Device (1) according to claim 1 or 2, wherein the electrode unit (10) can be fastened to the wall (30) of the container (3) by an adhesive effect and / or reversibly. [4] Device (1) according to one of claims 1 to 3, wherein the control device (11) during the evaluation relates to each other those response signals which are assigned to interrogation signals with different frequencies and each to a sensor electrode (100) and / or data dependent thereon and generates the relation results. [5] Method for monitoring a medium (2, 2') in a container (3), the method comprising at least the following steps: that several sensor electrodes (100) are attached to a wall (30) of the container (3), that the sensor electrodes (100) are supplied with interrogation signals, where the query signals are electrical signals with predeterminable frequencies, that response signals are received, that those response signals which are assigned to query signals with different frequencies and / or data dependent thereon are related to each other and relation results are generated, and that evaluates the relation results to determine which state the medium (2, 2') has in the container (3). [6] Method according to claim 5, wherein those response signals which are assigned to interrogation signals with different frequencies and each to a sensor electrode (100) and / or data dependent thereon are related to one another and relation results are generated.

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