PROCESS FOR MEASUREMENT OF THE LEVEL OF A MEDIUM IN A CONTAINER BASED ON THE RADAR PRINCIPLE

Abstract

A process for measurement of the level of a medium in a container based on the radar principle in which a measurement signal is generated and emitted in the direction of the medium, the portion of the measurement signal which has been reflected back is detected and the level determined from the propagation time of the measurement signal. The portion of the measurement signal which has been reflected back is evaluated in a phase-sensitive manner in order to assign the respective level corresponding to the propagation time of the measurement signal to a specific direction of space. Thus, the level is determined even under difficult conditions, such as when structures or devices are present in the container or when loose bulk materials are present in loose bulk cones.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a level measurement device for executing the level measurement process according to a preferred embodiment of the invention,

FIG. 2 shows a receiving antenna used for executing the level measurement process according to a preferred embodiment of the invention, and

FIG. 3 schematically shows the phase-sensitive evaluation of the portion of the measurement signal which has been reflected back.

DETAILED DESCRIPTION OF THE INVENTION

The level measurement device shown in FIG. 1 for executing a level measurement process according to a preferred embodiment of the invention is used for a container 1, in which there is a medium 2, here, specifically a loose bulk material with a loose bulk cone 3. The level measurement device has a transmitting and receiving antenna means 4 with a transmitting antenna means 5 and a receiving antenna means 6. A microwave signal produced in a microwave generation means 7 is supplied to the transmitting antenna 5 and emitted by it, as indicated in FIG. 1 with the broken lines, at the same time in essentially the entire solid angle facing the medium 2. As is recognized, this can take place in a host of ways, among others, specifically by using a transmitting antenna means 5 comprised of a host of individual antennae and a downstream dielectric lens.

The measurement signal emitted by the transmitting antenna means 5 is then reflected in the container 1, specifically on the surface of the medium 2 and partially also on the inside walls 8 of the container 1. These measurement signal portions which have been reflected back among others strike the receiving antenna 6 as is made below:

As shown schematically in FIG. 2, the receiving antenna means 6 is a patch antenna which is comprised of a host, here 5×5 individual antenna elements 9. As is furthermore apparent from FIGS. 1 & 3, the receiving antenna means 6, and thus, the individual antenna elements 9 are connected upstream of the signal processing means 10. In this signal processing means 10, phase-sensitive evaluation of the portions of the reflected-back measurement signal which have been received by the individual antenna elements takes place. This is shown schematically in FIG. 3 by phase shifters 11 which, however, are not implemented here as microwave phase shifters, but within the framework of signal processing using software. Thus, for each respective individual antenna element 9, a phase-sensitive signal is produced which within the framework of signal processing 12 ultimately enables determination of the topology of the medium 2 located in the container 1 via the distance corresponding to the respective solid angle between the transmitting antenna 5, the reflecting point of the medium 2 and the receiving antenna.

At known dimensions of the container 1, the volume of the medium 2 can thus be determined and output, as shown in FIG. 3. Thus, especially for loose bulk materials with a loose bulk cone, in spite of the absence of a defined level, a reliable quantity for the amount of the medium 2 in the container 1 can be obtained.

Claims

1. Process for measurement of the level of a medium in a container based on the radar principle, comprising the steps of: generating a measurement signal and emitting it toward the medium in the container,detecting a portion of the measurement signal which has been reflected back, anddetermining the level of the medium by the propagation time of the measurement signal,wherein at least one portion of the measurement signal which has been reflected back is evaluated in a phase-sensitive manner and the respective level assigned corresponding to the propagation time of the measurement signal relative to a specific direction of space.

2. Process in accordance with claim 1, wherein the measurement signal is emitted in a host of directions.

3. Process in accordance with claim 2, wherein the measurement signal is emitted at the same time essentially into the entire angular region facing the medium.

4. Process in accordance with claim 3, wherein a plurality of individual antenna elements is used to detect a number of reflected-back portions of the measurement signal.

5. Process in accordance with claim 2, wherein a plurality of individual antenna elements is used to detect a number of reflected-back portions of the measurement signal.

6. Process in accordance with claim 5, wherein the reflected-back portion of the measurement signal received by the respective individual antenna element is subjected to a respective phase shift.

7. Process in accordance with claim 5, wherein the receiving antenna is an array of patch antennas.

8. Process in accordance with claim 1, comprising the further step of determining the topography of the medium in the container by means of the level values determined for the different directions of space.

9. Process in accordance with claim 8, wherein the volume of the medium is computed by means of its topography.

10. Process in accordance with claim 5, comprising the further step of determining the topography of the medium in the container by means of the level values determined for the different directions of space.

11. Process in accordance with claim 10, wherein the volume of the medium is computed by means of its topography.