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US 12,644,862 B2Granted
Device for the inductive determination of the electrical conductivity of a medium contained in a container
AssigneeEndress+Hauser Conducta GmbH+Co. KG
InventorsSebastian Geissler, Robert Lichtenheldt, Ronny Michael
Life of this patent
Estimating the term…
Abstract
A measuring arrangement for determining the electrical conductivity of a measuring fluid comprises a gradiometer including an excitation coil and a first and a second receiver coil. The first and second receiver coils and the measuring fluid are inductively coupled to the excitation coil. The measuring arrangement includes a measuring circuit for exciting the excitation coil, for detecting an electrical signal from the receiver coils, and for deriving the electrical conductivity of the measuring fluid from the signal. All coils consist of a conductive material that has a resistance temperature coefficient which at 20° C. is less than 3.93*10−3 K−1.
Claims11
A measuring arrangement for determining an electrical conductivity of a measuring fluid, comprising:
- a gradiometer, including:
- an excitation coil, wherein the excitation coil is configured as a transmitter coil;
- a first receiver coil;
- and
- a second receiver coil,
- wherein the first and second receiver coils and the measuring fluid are inductively coupled to the excitation coil;
- a measuring circuit that is configured to excite the excitation coil to generate an alternating field passing through the receiver coils and the measuring fluid and to detect an electrical signal from the receiver coils and to derive the electrical conductivity of the measuring fluid from the signal, wherein the alternating field generated in the excitation coil induces a ring-shaped alternating current and thereby a magnetic field which runs in the first and second receiver coils and in the liquid medium, wherein an alternating electrical current and thus a magnetic field is induced in the measuring fluid, wherein the first receiver coil is more strongly penetrated by the magnetic field of the measuring fluid than the second receiver coil, wherein preferably the second receiver coil is not penetrated by the magnetic field induced in the measuring fluid;
- and
- a container in which the measuring fluid is contained, wherein the gradiometer is at least partially connected to a wall of the container or is arranged adjacent to the container wall, wherein the container consists of electrically non-conductive material at least in the region of the gradiometer,
- wherein the excitation coil and the first and the second receiver coils are embodied of a conductive material that has a resistance temperature coefficient which at 20° C. is less than 3.93*10−3 K−1.
7 more elements
A method for determining the electrical conductivity of a measuring fluid, comprising:
- providing a measuring arrangement, including:
- a gradiometer, including:
- an excitation coil, wherein the excitation coil is configured as a transmitter coil;
- a first receiver coil;
- and
- a second receiver coil,
- wherein the first and second receiver coils and the measuring fluid are inductively coupled to the excitation coil;
- a measuring circuit that is configured to excite the excitation coil to generate an alternating field passing through the receiver coils and the measuring fluid and to detect an electrical signal from the receiver coils and to derive the electrical conductivity of the measuring fluid from the signal, wherein the alternating field generated in the excitation coil induces a ring-shaped alternating current and thereby a magnetic field which runs in the first and second receiver coils and in the liquid medium, wherein an alternating electrical current and thus a magnetic field is induced in the measuring fluid, wherein the first receiver coil is more strongly penetrated by the magnetic field of the measuring fluid than the second receiver coil, wherein preferably the second receiver coil is not penetrated by the magnetic field induced in the measuring fluid;
- and
- a container in which the measuring fluid is contained, wherein the gradiometer is at least partially connected to a wall of the container or is arranged adjacent to the container wall, wherein the container consists of electrically non-conductive material at least in the region of the gradiometer,
- wherein the excitation coil and the first and the second receiver coils are embodied of a conductive material that has a resistance temperature coefficient which at 20° C. is less than 3.93*10−3 K−1;
- exciting the excitation coil to generate an alternating magnetic field which passes symmetrically through the first receiver coil and the second receiver coil and induces a magnetic field in the measuring fluid which is directed opposite to the alternating magnetic field, wherein the receiver coils are exposed at different intensities to the magnetic field which is induced by the alternating magnetic field in the measuring fluid and which is directed opposite to the alternating magnetic field;
- detecting an electrical signal of the receiver coils;
- and
- determining the electrical conductivity of the measuring fluid based upon the electrical signals detected by the receiver coils.
12 more elements
Dependencies are inferred from the claim text.