Liquid level measuring device with first working mode and second working mode

Abstract

The invention relates to a liquid level measuring device for process automation in an industrial or domestic environment, comprising a control circuit configured to selectively perform a liquid level measuring operation of the liquid level measuring device in a first operating mode or a second operating mode, wherein the second working mode has interference echo suppression different from that of the first working mode.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to German Patent Application No. 10 2023 206 031.0, filed on 27 June 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of liquid level measurement technology. More specifically, this invention relates to a liquid level measuring device for process automation in industrial or domestic environments, a method for performing liquid level measuring operations of the liquid level measuring device, a program unit, and a computer-readable medium. Background Technology

[0004] In liquid level measurement technology, the liquid level measuring device typically includes an antenna that transmits a measurement signal toward the surface of the measured medium and receives the measurement signal reflected back from the liquid surface, thereby calculating the liquid level. Examples of such measuring devices include liquid level radar equipment.

[0005] The antenna of a liquid level measuring device typically extends into the container, thus exposing it to the container's atmosphere. This can lead to contamination of the antenna surface, adversely affecting measurement quality. To remove such deposits from the liquid level measuring device or container, a cleaning system, such as a spray ball, can be used, which removes the deposits by spraying a cleaning medium onto the antenna of the liquid level measuring device.

[0006] However, the cleaning process may affect the measurement results and may lead to inaccurate or even false measurements. Summary of the Invention

[0007] In this context, the purpose of this invention is to provide a solution that can maintain measurement quality to a minimum even under drastic changes in environmental conditions.

[0008] This objective is achieved through the features of the independent claims. Further improvements to the invention are derived from the dependent claims and the following description of embodiments.

[0009] A first aspect of the invention relates to a liquid level measuring device configured for process automation in industrial or domestic environments. The liquid level measuring device includes control circuitry configured to selectively perform liquid level measuring operations in a first operating mode or a second operating mode, wherein the second operating mode has interference echo suppression distinct from the first operating mode. Specifically, the different operating modes can be configured by the user. In particular, it can also be configured that two or more operating modes exist.

[0010] The term echo interference suppression originates from the field of analysis of echo curves. For example, a structure in the container can cause a reflection of the measurement signal and can be identified in the measured echo curve. Usually, it is difficult to distinguish such an echo interference from an actual level echo, so that the echo curve can be misinterpreted and a false level value can be calculated.

[0011] However, if it is known that an echo interference is to be expected at a specific position in the echo curve, this echo interference can be suppressed in the analysis of the echo curve.

[0012] In the second operating mode, the level measuring device has a (or additional) echo interference suppression which is distinguished from the first operating mode. For example, the first operating mode is a regular level measurement mode, and the second operating mode is activated when the atmosphere in the container is changed drastically due to a special situation. Examples of such special situations include a filling process of the container or a cleaning process using a cleaning device, for example a spray ball. During a filling process, especially when a medium with splashing and sticky properties is added, deposits can form on the antenna which, if not identified, can lead to a measurement error. Similarly, during a cleaning process, similar situations can occur, for example a water film, a water column or a spray generated by a spray ball or other spraying device can be identified as a level and thus lead to a false measurement result.

[0013] However, if the level measuring device knows that a cleaning process is currently activated, the control circuit can identify the echo interference generated by the spray film of the spraying device as an interference signal and suppress it.

[0014] Similarly, during a fast filling with a medium having splashing and sticky properties, the control circuit can also monitor whether the antenna is contaminated by deposits and suppress the associated echo interferences.

[0015] According to an embodiment of the application, the second operating mode has a lower measurement accuracy than the first operating mode. By means of this lower measurement accuracy, "smaller" echo interferences can not be identified as echo signals in the echo analysis and thus not as level echoes. In order to still achieve a good measurement quality, it can be provided that the second operating mode has a higher single level measurement time than the first operating mode. It can also be provided to have a lower single level measurement time, since only small changes in the level are expected during a cleaning process. In particular, a plurality of level measurement results can be averaged.

[0016] According to another embodiment of the application, the second operating mode has an echo interference suppression of echo interferences generated by splashes or dust clouds during a fast filling process.

[0017] According to a further embodiment of the application, the second operating mode is triggered by an activation command sent from an external control device to the spraying device, or by a start command for starting a filling process.

[0018] According to a further embodiment of the application, the control circuit is configured to detect deposits on the antenna of the level measuring device and to trigger a cleaning process and to switch from the first operating mode to the second operating mode in dependence thereon.

[0019] According to a further embodiment of the application, the control circuit is configured to determine whether deposits are still present on the antenna after the second operating mode has ended and the first operating mode has been switched back.

[0020] According to a further embodiment of the application, the control circuit is configured to trigger a cleaning process again when the control circuit determines that deposits are still present on the antenna.

[0021] A further aspect of the application relates to a method for selectively performing a level measuring operation of a level measuring device in a first operating mode or in a second operating mode. In the method, the level measuring operation is first performed in the first operating mode. Upon receipt of a control command from an external control device, the first operating mode is switched to the second operating mode. Subsequently, the level measuring operation is continued in the second operating mode, wherein the second operating mode has a disturbance echo suppression which is different from the first operating mode.

[0022] According to a further embodiment of the application, the control command is an activation command sent to the spraying device, or a start command sent to a filling process.

[0023] A further aspect of the application relates to a program element for instructing a level measuring device to perform the method steps described above and below when the program element is executed on a control circuit of the level measuring device.

[0024] A further aspect of the application relates to a computer readable medium having stored the program element described above.

[0025] "Process automation in an industrial environment" can be understood as a branch of the technical field which deals with the implementation of operational control of machines and devices without human involvement. One of the goals of process automation is to achieve an automatic coordinated operation of the individual components within a plant in the chemical, food, pharmaceutical, oil, paper, cement, shipping or mining industries, for example. For this purpose, a variety of sensors can be used, which are designed in particular for the special requirements of the process industry, for example with good mechanical stability, are not susceptible to contamination, can withstand extreme temperatures and high pressures, etc. The measurement data of these sensors is usually transmitted to a control center, in which process parameters such as level, limit level, flow, pressure or density can be monitored and the operational settings of the entire plant can be adjusted manually or automatically.

[0026] One subfield of process automation in an industrial environment relates to logistics automation in factories and in supply chains. In logistics automation, with the aid of distance and angle sensors, it is possible to achieve automated control of processes inside or outside a building or inside individual logistics devices. Typical application examples include logistics automation systems in airport baggage and cargo handling, traffic monitoring (e.g. toll systems), the retail sector, parcel distribution systems, or access control in the field of building security. The common requirement in these application scenarios is that, in combination with presence detection, the size and position of a target object must be measured precisely. For this purpose, sensors based on optical measurement principles can be used, such as lasers, LEDs, two-dimensional cameras or three-dimensional cameras, which implement distance measurement by means of the Time of Flight (ToF) principle.

[0027] Another subfield of process automation in an industrial environment relates to factory / manufacturing automation. Its application scenarios span a number of industries, such as automotive manufacturing, food processing, the pharmaceutical industry, or the packaging sector in general. The goal of factory automation is to achieve automated control of the production process for a product by means of machines, production lines and / or robots, i.e. to complete the production flow without human intervention. The sensors used in this process and their precision requirements in measuring the position and size of objects are similar to the application scenarios in logistics automation described above.

[0028] The use of the terms in the claims is intended to be assigned a meaning in accordance with the foregoing description. For example, the use of the articles "a" or "the" preceding a recited element does not preclude the existence of more than one of the recited element. Also, the use of the term "or" is intended to mean an inclusive "or" rather than an exclusive "or" unless the context clearly indicates otherwise. For example, the phrase "A or B" is intended to mean "A or B or both A and B." Further, the use of the term "at least one" is intended to mean one or more of the recited elements, whether such elements are listed individually or in combination with another element. Further still, the use of the term "and / or" is intended to mean "and" or "or," or both, as the context dictates.

[0029] Further embodiments of the application will be described with reference to the drawings. The representations in the drawings are schematic and not to scale. Where the same reference signs are used in the following description of the drawings, this indicates that the signs refer to the same or similar elements. BRIEF DESCRIPTION OF DRAWINGS

[0030] Fig. 1 shows a schematic diagram of a level measuring device according to an embodiment of the application in a first state.

[0031] Fig. 2 shows a schematic diagram of the level measuring device of Fig. 1 in a second state.

[0032] Fig. 3 shows a flow chart of a method according to an embodiment of the application. DETAILED DESCRIPTION

[0033] Fig. 1 shows a level measuring system according to an embodiment of the application in a first state. The level measuring system comprises a level measuring device 100 mounted on a container 105, wherein the antenna of the level measuring device 100 is exposed to the atmosphere inside the container. The container 105 contains a liquid filling medium 106, the level of which is measured in a contactless manner.

[0034] The container further comprises a cleaning device 103, for example in the form of a spray ball.

[0035] The spray ball 103 can spray a cleaning liquid for cleaning the container, in particular for cleaning the level radar antenna. The spray ball can also be used for sterilization. In this context, the process is referred to as sterilization in process (SIP).

[0036] The level measuring device 100 is connected to an external control device 102 and to a display device 104, either by wire or wirelessly. In the normal operating state shown in Fig. 1, the level measuring device is in a first state. At this time, the temperature in the container 105 is also in the normal operating temperature, for example 80 degrees Celsius.

[0037] Fig. 2 shows the measuring system of Fig. 1, but now in a higher temperature state, for example 130 degrees Celsius. The cleaning device 103 is performing a cleaning operation, and the antenna of the level measuring device 100 is being cleaned. In order to start the cleaning process, the external control device 102 sends a corresponding control command to the spray ball. The command can also be sent to the level measuring device, in particular to the control circuit 101 of the level measuring device, so that it switches from the first state to the second state. It is also possible to provide for two different commands to be sent by the control device 102: one command to the spray device 103 for starting the spraying process, and another command to the control circuit 101 for switching the level measuring device from the first state to the second state.

[0038] In the cleaning process shown in Fig. 2, the system is subjected to varying environmental conditions (increased humidity, increased temperature). Since the level measuring device is switched to the second operating mode, reliable level measurement is possible even under such environmental conditions. The second operating mode is particularly insensitive to environmental disturbances.

[0039] For example, an enhanced noise suppression strategy can be employed during the cleaning process, so that the level measurement function is additionally implemented in addition to the normal measurement.

[0040] When the spraying process is finished, the level measuring device can be set to recognize this (since the end of spraying causes a change in the echo curve) and automatically switches back to the first operating mode. If the level measuring device subsequently detects in the first operating mode that there are still significant deposits on the antenna, which affect the measurement or even make it impossible, the device judges that the cleaning is insufficient and restarts the spraying process. At the same time, the level measuring device is again switched from the first operating mode to the second operating mode shortly before, during or after the renewed spraying.

[0041] The deposits can be recognized in particular by detecting an echo signal in the echo curve close to the position of the antenna.

[0042] Fig. 3 shows a flowchart of a method according to an embodiment of the application. In step 301, the level measuring device is switched to the first operating mode and performs a level measurement in step 302. In step 303, the cleaning process is started and the level measuring device is switched to the second operating mode. In step 304, a level calculation is performed in the second operating mode. In step 305, the cleaning process is stopped and in step 306, the level measuring device detects after switching back to the first operating mode that there are still deposits on the antenna, so that the flow jumps back to step 302 and the cleaning process is restarted.

Claims

1. A level measuring device (100) configured for process automation in an industrial or domestic environment, the level measuring device (100) comprising: a control circuit (101) configured for selectively performing a level measuring operation of the level measuring device in a first operating mode or a second operating mode; wherein the second operating mode has an interference echo suppression that is distinct from the first operating mode.

2. The level measuring device (100) according to claim 1, wherein the second operating mode has a lower measurement accuracy than the first operating mode.

3. The level measuring device (100) according to claim 1 or 2, wherein the second operating mode has a higher single level measurement time or a greater average value of consecutive level measurements than the first operating mode.

4. The level measuring device (100) according to any of the preceding claims, wherein the first operating mode has an interference echo suppression of interference echoes caused by a spray film of a spray ball.

5. The level measuring device (100) according to any of the preceding claims, wherein, the second operating mode has an interference echo suppression of interference echoes caused by splashes or dust clouds in a fast filling process.

6. The level measuring device (100) according to any of the preceding claims, wherein the second operating mode is triggered by an activation command to a sprinkling device (103) from an external control device (102) or by a start command for starting a filling process.

7. The level measuring device (100) according to any of the preceding claims, wherein the control circuit (101) is configured to detect a deposit on an antenna (104) of the level measuring device and to trigger a cleaning process and to switch from the first operating mode to the second operating mode in dependence thereon.

8. The level measuring device (100) according to any of the preceding claims, wherein the control circuit (101) is configured to determine whether a deposit is still present on the antenna after the second operating mode has ended and the first operating mode has been switched back.

9. The level measuring device (100) according to claim 8, wherein the control circuit (101) is configured to trigger a cleaning process again if it is determined that a deposit is still present on the antenna.

10. A method for selectively performing a level measuring operation of a level measuring device in a first operating mode or a second operating mode, comprising the following steps: performing the level measuring operation in the first operating mode; receiving a control command from an external control device (102); performing the level measuring operation in the second operating mode; wherein the second operating mode has an interference echo suppression that is distinct from the first operating mode.

11. The method according to claim 10, wherein, the control command is an activation command to a sprinkling device (103) or a start command to a filling process.

12. A program element, which, when executed on a control circuit (101) of a level measuring device (100), causes the level measuring device to perform the following steps: performing the level measuring operation in the first operating mode; receiving control instructions from an external controller (102); performing the liquid level measurement operation in the second operating mode; wherein, the second operating mode has a disturbance echo suppression that is different from the first operating mode.

13. A computer readable medium, in which the program element of claim 12 is stored.

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