OPTICAL FILL LEVEL MEASURING DEVICE

Abstract

An optical level measuring device configured to measure a fill level of a medium through the container wall of a plastic container, having an optical distance sensor as well as a radar sensor.

Claims

1. An optical level measuring device configured to measure a fill level of a medium through a container wall of a plastic container, comprising: optical distance sensor circuitry configured to emit a light signal through the container wall in a direction of a product surface and to receive the light signal reflected at the product surface, also through the container wall; and evaluation device circuitry configured to determine a fill level or to detect a limit level of the medium in the plastic container by evaluating the received light signal.

2. The optical level measuring device according to claim 1, further comprising: a radar sensor configured to emit a radar signal through the container wall in the direction of the product surface and to receive the radar signal reflected at the product surface, also through the container wall, wherein the evaluation device is configured to determine the fill level or limit level of the medium in the plastic container by evaluating the received radar signal.

3. The optical level measuring device according to claim 1, wherein the evaluation device is configured to first perform the evaluation of the received radar signal and, when this evaluation is ambiguous, to perform the evaluation of the received light signal.

4. The optical level measuring device according to claim 1, wherein the evaluation device is configured to first perform the evaluation of the received radar signal and, only when this evaluation is ambiguous, to perform a measurement with the optical distance sensor and to perform the evaluation of the received light signal.

5. The optical level measuring device according to claim 1, wherein the light signal is a laser signal.

6. The optical level measuring device according to claim 1, further comprising: a housing in which the optical distance sensor and the radar sensor are disposed.

7. The optical level measuring device according to claim 1, further comprising: a radio communication interface arranged to transmit the measured value to an external computing unit.

8. The optical level measuring device according to claim 1, configured as a stand-alone level measuring device, without external power supply.

9. The optical level measuring device according to claim 1, configured to be adhered to the outside of the plastic container.

10. (canceled)

11. (canceled)

12. A fill level measuring arrangement for measuring a fill level of a medium through a container wall of a plastic container, comprising: an optical level measuring device with an optical distance sensor, configured to emit a light signal through the container wall in a direction of a product surface and to receive the light signal reflected at the product surface, also through the container wall; an evaluation device configured to determine a fill level or to detect a limit level of the medium in the plastic container by evaluating the received light signal; and a plastic container having the optical level measuring device attached to the outside thereof.

13. A method of measuring a fill level of a medium through a container wall of a plastic container, comprising the steps of: emitting a light signal through the container wall in a direction of a product surface and receiving the light signal reflected at the product surface, also through the container wall; and determining a fill level or detecting a limit level of the medium in the plastic container by evaluating the received light signal.

14. A non-transitory computer readable medium having stored thereon a program element which, when executed on an evaluation device of a fill level measuring device for measuring a fill level of a medium through a container wall of a plastic container, instructs the fill level measuring device to implement a method of measuring the fill level of the medium through the container wall of the plastic container, comprising: emitting a light signal through the container wall in a direction of a product surface and receiving the light signal reflected at the product surface, also through the container wall; and determining a fill level or detecting a limit level of the medium in the plastic container by evaluating the received light signal.

15. (canceled)

16. The optical level measuring device according to claim 2, wherein the evaluation device is configured to first perform the evaluation of the received radar signal and, when this evaluation is ambiguous, to perform the evaluation of the received light signal.

17. The optical level measuring device according to claim 2, wherein the evaluation device is configured to first perform the evaluation of the received radar signal and, only when this evaluation is ambiguous, to perform a measurement with the optical distance sensor and to perform the evaluation of the received light signal.

18. The optical level measuring device according to claim 3, wherein the evaluation device is configured to first perform the evaluation of the received radar signal and, only when this evaluation is ambiguous, to perform a measurement with the optical distance sensor and to perform the evaluation of the received light signal.

19. The optical level measuring device according to claim 2, wherein the light signal is a laser signal.

20. The optical level measuring device according to claim 3, wherein the light signal is a laser signal.

21. The optical level measuring device according to claim 2, further comprising: a housing in which the optical distance sensor and the radar sensor are disposed.

22. The optical level measuring device according to claim 3, further comprising: a housing in which the optical distance sensor and the radar sensor are disposed.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0032] FIG. 1 shows an optical level measuring device according to an embodiment.

[0033] FIG. 2A, FIG. 2B and FIG. 2C show three measurement curves at different fill levels.

[0034] FIG. 3 shows a flow diagram of a process according to an embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

[0035] FIG. 1 shows an optical level measuring device 100 which can determine the fill level or limit level of a medium in a plastic container from the outside by transmitting the radar signal from the radar sensor 103 and the light signal from the optical distance sensor 101 through the wall of the plastic container, reflecting off the medium, and then passing back through the wall into the measuring device where they are detected.

[0036] The optical distance sensor 101 and the radar sensor 103 are located within the same housing 104, for example a plastic housing. They are both connected to the evaluation device 102. The electronics within the measuring device are powered by the energy storage 110.

[0037] A radio communication interface 105 is provided, via which measurement data can be transmitted to the external device 106. It may be provided that the external device 106 sends parameterization data or control data to the measuring device 100. The external device 106 may be an external control unit, a mobile device such as a smartphone, or a cloud-based system.

[0038] The self-contained radar sensor 103 measures through the wall of the plastic container, and the measuring device can transmit the obtained measurement value to the cloud. Especially for low containers, typically with a container height of less than 1 m and a small DK value of the medium, such as oil, the effect can occur that the obtained echo curves of the radar measurement do not result in a clear fill level.

[0039] Depending on the constellation, the case may arise that it is no longer possible to distinguish between the state “container completely empty” and “container completely full”. In addition to the radar sensor 103, an optical distance sensor 101, for example a laser distance meter, is integrated in the level measuring device 100. This optical distance sensor also measures through the plastic container. This is possible because the plastic container is, for example, a semi-transparent IBC container made of HDPE material. The measurement result of the optical distance sensor 101 may be distorted by the container wall; however, the fill level is detected with sufficient accuracy to obtain an unambiguous measurement result in combination with the radar measurement.

[0040] The optical level measuring device 100 is mounted on an IBC container, for example. This can be seen in FIGS. 2A, 2B and 2C. Here, the level measuring device 100 measures through the container wall. Both the light signal from the distance sensor and the radar signal from the radar sensor are reflected from the product surface 202 of the product 201 and received back into the level measuring device.

[0041] FIG. 2A shows the case of an approximately half-filled container 200. Two peaks 401, 402 are found in the echo curve detected by the radar sensor. Peak 401 corresponds to the reflection at the product surface 202 and peak 402 corresponds to the reflection of the radar signal at the container bottom.

[0042] Thus, both the level echo and the bottom echo are recognizable in the echo curve.

[0043] However, the radar measurement cannot distinguish between minimum and maximum fill level. These two cases are shown in FIG. 2B (maximum fill level) and 2C (minimum fill level). In both cases, only the peak 402 of the bottom echo can be detected in the echo curve detected by the radar sensor.

[0044] If the measuring signal of the optical distance sensor is now additionally evaluated, the uniqueness can be restored. Although the optical distance signal provides a rather inaccurate measuring signal (for example with an accuracy of ±50 mm), this is sufficient to distinguish between fill level max and fill level min.

[0045] FIG. 3 shows a flow diagram of a method according to an embodiment. In step 301, the method starts and in step 302, a first radar measurement is performed. In step 303, it is determined whether the radar fill level measurement has led to a clear measurement result. If this is the case, the fill level is output by the measuring device in step 306 and the procedure ends with step 307. If this is not the case, however, an optical measurement 304 is performed by an optical distance sensor. This is used to “plausibilize” the fill level measurement or to determine whether the container is completely full or completely empty.

[0046] After this plausibility check, the fill level is output in step 306 and the procedure ends with step 307.

[0047] Additionally, it should be noted that “comprising” and “comprising” do not exclude other elements or steps, and the indefinite articles “one” or “a” do not exclude a plurality. It should further be noted that features or steps that have been described with reference to any of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be regarded as limitations.