Method for operating a contactless ultrasound or radar fill level measuring device and contactless ultrasound or radar fill level measuring device practicing said method

Abstract

A method for operating a contactless ultrasound or radar fill level measuring device having at least one open distribution transmitter, at least one receiver and at least one evaluation unit having the following steps: emitting a transmitter signal by the transmitter, receiving a reflection signal reflected on a reflector by the receiver, evaluating the transmitter signal and/or the reflection signal with the evaluation unit which identifies a frequency shift between the transmitter signal and the reflection signal. By evaluating the determined frequency shift or a variable derived from the determined frequency shift, a filling event is detected, in which a filling stream at least partially passes through the transmitter signal. Furthermore, a contactless ultrasound or radar fill level measuring device which performs this method.

Claims

1. A method for operating a contactless fill level measuring device having at least one open distribution transmitter, at least one receiver and at least one evaluation unit, the method comprising following steps: emitting a transmitter signal from the transmitter, using the receiver for receiving a reflection signal reflected on a reflector, using the evaluation unit for evaluating at least one of the transmitter signal and the reflection signal, identifying a frequency shift between the transmitter signal and the reflection signal with the evaluation unit, and detecting a filling event, in which a filling stream at least partially passes through the transmitter signal by evaluating the determined frequency shift or a variable derived from the determined frequency shift, wherein the evaluation unit determines a reflection speed from the identified frequency shift and detects the filling event by comparing the reflection speed to a predetermined speed limit; and outputting occurrence of the filling event detected.

2. The method according to claim 1, wherein the predetermined speed limit is specified depending on a maximum speed of a fill product surface.

3. The method according to claim 1, wherein the evaluation unit identifies a transit time of the reflection signal before, after or during detection of the filling event, and determines a fill level from the identified transit time.

4. The method according to claim 3, wherein the evaluation unit outputs a determined fill level and a measured fill level, and wherein the measured fill level is characterized as unreliable when the evaluation unit detects a filling event.

5. The method according to claim 1, wherein fill level measurement is interrupted when the evaluation unit detects a filling event.

6. A contactless fill level measuring device comprising: at least one open distribution transmitter for emitting a transmitter signal, at least one receiver for receiving a reflection signal reflected on a reflector, and at least one evaluation unit having means for evaluating at least one of the transmitter signal and the reflection signal, wherein, in an operating state, the evaluation unit is adapted for identifying a frequency shift between the transmitter signal and the reflection signal and for identifying a filling event by evaluating the identified frequency shift or a variable derived from the identified frequency shift resulting from a filling stream at least partially passing through the transmitter signal, wherein, in the operating state, the evaluation unit is adapted for determining a reflection speed from the identified frequency shift and for detecting the filling event by comparing the reflection speed to a predetermined speed limit; and wherein the evaluation unit is operative for outputting occurrence of the detected filling event.

7. The fill level measuring device according to claim 6, wherein, in the operating state, the evaluation unit is adapted for identifying a transit time of the reflection signal, before, after or during detection of the filling event, and for determining the fill level from the transit time.

8. The fill level measuring device according to claim 6, wherein, in the operating state, the evaluation unit is adapted for outputting a detected filling event and the measured fill level, and wherein the measured fill level is characterized as unreliable when the evaluation unit detects the filling event.

9. The fill level measuring device according to claim 6, wherein, in the operating state, the evaluation unit is adapted for interrupting the fill level measurement when the evaluation unit (8) detects a filling event.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a filling of a container with an embodiment of a fill level measuring device according to the invention arranged on a container, and which is implemented according to a first embodiment of the method according and

(2) FIG. 2 is a flow chart of a second embodiment of a method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(3) A filling assembly 1 having a contactless ultrasound or radar fill level measuring device 2 is shown in operation in FIG. 1. The fill level measuring device 2, in each case, has an open distribution transmitter 3 that emits a transmitter signal 4, a receiver 5 that receives a reflection signal 7 reflected on a reflector 6, and an evaluation unit 8 that evaluates the transmitter signal 4 and/or the reflection signal 7. The evaluation unit 8 identifies a frequency shift between the transmitter signal 4 and the reflection signal 7, and by evaluating the identified frequency shift or a variable derived from the identified frequency shift, detects a filling event in which a filling stream 9 at least partially passes through the transmitter signal 4.

(4) In detail, FIG. 1 shows the situation of the filling event of a container 10, wherein fill product in the form of a filling stream 9 is filled into the side of the container 10. The filling stream 9 passes through the transmitter signal 4 emitted by the transmitter 3 of the fill level measuring device 2, whereby the filling event is detected by the evaluation unit 8.

(5) By detecting the filling event with the help of the shown method 1 and the fill level measuring device 2, particularly reliable fill level measurement is provided.

(6) The following explanations relate both to the embodiment of the method for operating a contactless ultrasound or radar fill level measuring device 2 as well as to the fill level measuring device 2 shown.

(7) In the illustrated embodiments, the evaluation unit 8 of the fill level measuring device 2 determines the reflector speed from the identified frequency shift and detects the filling event by comparing the reflector speed to a predetermined speed limit. Presently, the speed limit is a value predetermined before start-up of the fill level measuring device 2. Alternatively, the speed limit can also be specified in dependence on the maximum speed of the fill product surface and, in this respect, dependent on the fill product. By detecting the filling event using the speed of the reflector 6, the filling event itself can be recognized when the reflector 6 has a small distance to the fill product surface. In this respect, the filling event can be recognized in a particularly reliable manner.

(8) Additionally, the evaluation unit 8 presently identifies the transit time of the reflection signal 7 after detecting the filling event and determines the fill level within the container 10 from the identified transit time. Consequently, information about the fill level and/or about the arrangement of the fill level measuring device 2 over the filling stream 9 as well as about the fill level of the container 10 can be obtained from the reflection signal 7 with the method shown and the fill level measuring device 2. In this respect, the method and the fill level measuring device 2 are designed in a particularly simple manner.

(9) Furthermore, the evaluation unit 8 outputs the detected fill level and the measured fill level, wherein the measured fill level is characterized as unreliable when the evaluation unit 8 detects a filling event. Presently, a display unit 11 is provided via which the detected fill level and the measured fill level are output. The display unit 11 visualizes the transmitted values for the user. Alternatively, a corresponding display unit can be integrated in the evaluation unit. Optionally, fill level measurement is interrupted when a filling event is detected. The output of erroneous or non-characterized unreliable measured values is thus prevented.

(10) As a result, a method and a fill level measuring device 2 are shown, which, due to the recognition and consideration of the dynamic interference source of the filling event during fill level measurement, have a particularly high degree of reliability of the output measured fill level.

(11) FIG. 2 shows a second embodiment of a method according to the invention for operating a contactless ultrasound or radar fill level measuring device having at least one open distribution transmitter, at least one receiver and at least one evaluation unit, which provides particularly reliable measured fill levels.

(12) In a first step 100, the transmitter emits transmitter signals, which are reflected on a reflector and then received 101 by a receiver. The transmitter and/or reflection signal is evaluated 102 in the next step, wherein a frequency shift between the transmitter signal and the reflection signal is identified 103, from which, in turn, the reflector speed is determined in step 105.

(13) In step 106, by comparing the reflector speed to a speed limit, which is specified depending on the maximum speed of the fill product surface in step 107, the filling event is detected in step 104.

(14) In an advantageous manner, the method uses the speed information of the reflector in order to recognize whether a filling stream passes through the transmitter signal, and in this respect, this is to be taken into account in the further evaluation, or respectively, output of the measured fill level.

(15) After detecting the fill level 104, the transit time of the reflection signal is identified in step 108. Then, the detected fill level and the measured fill level are output in step 109, wherein the measured fill level is characterized as unreliable when the evaluation unit detects a filling event. In the illustrated embodiment, in step 110, fill measurement is interrupted as long as the evaluation unit detects a filling event.

(16) By taking the fill level into account in outputting the measured fill level and, in particular, by interrupting fill level measurement, as long as the evaluation unit detects a filling event, the output of erroneous or non-characterized unreliable measured fill levels is prevented, so that the output measured values according to this method have a particularly high reliability.