Device for determining and/or monitoring the density and/or the level of a filling material in a container

• US 20040025569A1
• Filed: 07/30/2003
• Published: 02/12/2004
• Est. Priority Date: 09/01/2000
• Status: Active Grant

• Current Assignee: Endress + Hauser GmbH + Company KG (Endress+Hauser AG)
• Original Assignee: Endress + Hauser GmbH + Company KG (Endress+Hauser AG)
• Inventors: Kamereit, Wolfgang, Damm, Hartmut, Neuhaus, Joachim
• Granted Patent: US 6,879,425 B2
• Time in Patent Office: Days
• US Class Current: 73/32R
• CPC Class Codes: G01F 23/288 X-rays; Gamma rays or other forms of ionising radiation
• CPC Class Codes: G01F 23/2885 for discrete levels
• CPC Class Codes: G01N 23/22 by measuring secondary emission from the material
• CPC Class Codes: G01N 9/24 by observing the transmission of wave or particle radiation through the material

Abstract

The invention relates to a device for determining and/or monitoring the density and/or the level (L) of a filling material (8) in a container (6). A transmitting unit (2) which emits radioactive radiation and a receiving unit (3) which is arranged in such a way that it receives the radioactive radiation or the secondary radiation that is produced by the interaction of the radioactive radiation with the filling material (8) are provided. A regulating/evaluating unit (13) which determines the density and/or the level of the filling material (8) in the container (6) using the measuring data that is supplied by the receiving unit (3) is also provided. The aim of the invention is to provide a device which enables the level or the density of a filling material in a container to be measured reliably. To this end, the receiving unit (3) consists of individual detector units (4). These detector units (4) are positioned at different distances from the floor of the container (6), so that each detector unit (4) directly or indirectly, essentially detects the proportion of radiation that passes through a defined partial area of the container (6) or that is produced in a defined partial area of the container (6).

Claims

1. A device for determining and/or monitoring the density and/or the level of a filling material in a container, in which a transmitting unit is provided that transmits radioactive radiation, and a receiving unit is provided that is disposed such that it receives the radioactive radiation, or the secondary radiation generated by interaction of the radioactive radiation with the filling material, and a regulating/evaluating unit is provided, which from the measurement data furnished by the receiving unit determines the density and/or the level of the filling material in the container,

characterized in that

the receiving unit (3) comprises individual detector units (4), and the detector units (4) are positioned at different distances from the floor of the container (6), so that each detector unit (4) directly or indirectly detects essentially the proportion of radiation that passes through a defined partial area of the container (6) or is generated in a defined partial area of the container (6).

3. The device of claim 1 or 2,

characterized in that

one detector unit (4) is a solid detector and/or a liquid detector.

4. The device of claim 1 or 2,

characterized in that

one detector unit (4) is a plastic scintillator or a crystal scintillator with a downstream photomultiplier or a downstream PIN diode.

5. The device of claim 1, 2 or 3,

characterized in that

one detector unit (4) is a semiconductor detector, for instance a CdZnTe detector.

6. The device of claim 1, 2, 3, 4 or 5,

characterized in that

the detector unit (4) comprises a single detector, or that one detector unit (4) is assembled from a plurality of individual detectors that are disposed such that they form a detector array (5).

7. The device of claim 1, 2, 3, 4, 5 or 6,

characterized in that

at least one first additional detector unit (9) is provided, which is disposed above a predetermined maximum level (H) of the filling material (8) in the container (6), and the first additional detector unit (9) receives essentially only the radioactive radiation emitted by the transmitting unit (2) that has not entered into interaction with the filling material (8).

8. The device of claim 1, 2, 3, 4, 5 or 6,

characterized in that

a pressure sensor (10) is provided that is disposed above a maximum level (H) of the filling material (8) in the container (6).

9. The device of claim 1, 2, 7 or 8,

characterized in that

at least one second additional detector unit (11) is provided, which is disposed such that it detects essentially only the radioactive background radiation in the immediate vicinity of the container (6).

10. The device of claim 1, 2, 3, 4, 5 or 6,

characterized in that

the distance between two successive detector units (4) is designed variably, and the distance is adapted to whatever the desired local resolution is.

11. The device of claim 1, 2 or 10,

characterized in that

the detector units (4) are disposed in a predetermined number on a retaining element (12), and the retaining element (12) is preferably embodied flexibly.

12. The device of one or more of the foregoing claims,

characterized in that

for the case where the detector units (4) have a temperature dependency, each detector unit (4) is assigned a temperature sensor, which determines the temperature at the measurement site;

and

that the regulating/evaluating unit (13) takes the temperature prevailing at the measurement site into account in evaluating the measured level or density data.

13. The device of one or more of the foregoing claims,

characterized in that

a bus line (17) is provided, by way of which the detector units (4) and the regulating/evaluating unit (13) communicate with a remote control point.

14. The device of one or more of the foregoing claims,

characterized in that

an input/output unit (14) is provided, by way of which the operator can select an arbitrary detector unit (4) to secure against overfilling;

and

that the regulating/evaluating unit (13), via the input/output unit (14), outputs a report accordingly as soon as the predetermined level (L) is reached.

15. The device of claim 1, 2 or one or more of claims 3-14,

characterized in that

the regulating/evaluating unit (13) determines the measurement data of the individual detector units (14) with the container (6) empty and sets up a corresponding empty profile;

that the regulating/evaluating unit (13) determines the measurement data of the individual detector units (4) with the container (6) full and sets up an actual measurement profile; and

that the regulating/evaluating unit (13), by comparison of the measurement profile with the empty profile, furnishes information about the formation of foam above the filling material (8) or the formation of scale on the container wall (7).

16. The device of claim 1 or 2,

characterized in that

the regulating/evaluating unit (13) sets up a density profile of the filling material (8) disposed in the container (6);

and

that taking the density profile into account, the regulating/evaluating unit (13) determines the level (L) of the filling material (8) in the container (6).

17. The device of claim 1 or 2,

characterized in that

the regulating/evaluating unit (13) sets up a density profile of the filling material (8) disposed in the container (6);

and

that taking the density profile into account, the regulating/evaluating unit (13) makes the density profile available to the operator for the sake of process analysis and/or for regulating purposes.

2. A device for determining and/or monitoring the density and/or the level of a radioactive filling material in a container, in which a receiving unit is provided which is disposed such that it receives the radiation of the radioactive filling material, and a regulating/evaluating unit, which from the measurement data furnished by the receiving unit determines the density and/or the level of the filling material in the container,

characterized in that

the receiving unit (3) comprises individual detector units (4), and the detector units (4) are positioned at different distances from the floor of the container (6), so that each detector unit (4) directly or indirectly detects essentially the proportion of radiation that passes through a defined partial area of the container (6) or is generated in a defined partial area of the container (6).

18. A device for determining and/or monitoring the density of a medium in a container, in which a transmitting unit is provided that transmits radioactive radiation, and a receiving unit is provided that is disposed such that it receives the radioactive radiation or the secondary radiation generated by interaction of the radioactive radiation with the filling material, and a regulating/evaluating unit is provided which from the measurement data furnished by the receiving unit determines the density of the medium in the container,

characterized in that

the receiving unit (3) comprises two detector units (4), and the detector units (4) are positioned in different positions along the container (24);

that each detector unit (4) directly or indirectly detects essentially the proportion of radiation that passes through a defined partial area of the container (24); and

that from the differing extinction of the proportions of radiation that are detected in the two detector units (4), the regulating/evaluating unit (13) determines the density of the medium (25) in the container (24).