# US 2021/0239506 A1 · Impedance Point Level Sensor

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- Number: US 2021/0239506 A1
- Document ID: US20210239506A1
- Status: Published application
- Kind: A1
- Application number: 17/050,498
- Filed: 2019-05-07
- Published: 2021-08-05
- Earliest claimed: 2018-05-08
- Assignees: VEGA Grieshaber KG
- Applicants: Vega Grieshaber KG
- Inventors: Christian Weinzierle; Juergen Haas
- Web page: https://patentgrep.com/patent/US20210239506A1

## CPC

- G01F 23/265: {for discrete levels}
- G01F 23/266: {measuring circuits therefor}
- G01F 23/268: {mounting arrangements of probes}
- G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME

## Abstract

The invention is an impedance threshold level sensor, comprising: a measuring probe which can be influenced by a medium surrounding the measuring probe in a measuring capacitance, the measuring probe comprising a measurement electrode and a reference electrode insulated from the measurement electrode, between which the measuring capacitance is formed, a measuring resonant circuit, in which the measuring probe is arranged as a capacitance-determining element, an electronic unit having a signal generator for exciting the measuring resonant circuit and a signal detector for determining a response signal of the measuring resonant circuit, a signal processing unit for generating a measurement signal, which is connected to the electronic unit, wherein the measurement electrode and the reference electrode are designed and arranged such that an increasing filling level of the medium reaches the reference electrode earlier than or together with the measurement electrode.

## Claims

### Claim 1

An impedance point level sensor comprising:
a measuring probe, which can be influenced by a medium surrounding the measuring probe in a measuring capacitance, the measuring probe comprising a measurement electrode and a reference electrode insulated from the measurement electrode, between which electrodes the measuring capacitance is formed,
a measuring resonant circuit, in which the measuring probe is arranged as a capacitance-determining element,
an electronic unit having a signal generator for exciting the measuring resonant circuit and a signal detector for determining a response signal of the measuring resonant circuit,
a signal-processing unit, which is connected to the electronic unit, for generating a measurement signal, and
wherein the measurement electrode and the reference electrode are designed and arranged in such a way that an increasing fill level of the medium reaches the reference electrode earlier than the measurement electrode simultaneously.

### Claim 2 (depends on 1)

The impedance point level sensor of claim 1, wherein the reference electrode has an extension in the direction of the measurement electrode.

### Claim 3 (depends on 2)

The impedance point level sensor of claim 2, wherein the extension is in the form of a pin, at least in some sections, wherein the extension protrudes beyond the front of the measurement electrode as seen in the axial direction.

### Claim 4 (depends on 3)

The impedance point level sensor of claim 3, wherein the extension is angled, wherein a first section is arranged on or fastened to the reference electrode, and a second section extends in the axial direction.

### Claim 5 (depends on 2)

The impedance point level sensor of claim 2, wherein the extension is in the form of a tube which fits over the measurement electrode in the axial direction.

### Claim 6 (depends on 5)

The impedance point level sensor of claim 5, wherein the tube is detachably connected to the reference electrode.

### Claim 7 (depends on 5)

The impedance point level sensor of claim 5, wherein the tube has one or more openings, at least at an end on the reference electrode side.

### Claim 8 (depends on 2)

The impedance point level sensor of claim 2, wherein the extension is in the form of a metallisation which extends in the axial direction.

### Claim 9 (depends on 2)

The impedance point level sensor of claim 2, wherein the metallisation is strip-shaped.

### Claim 10 (depends on 8)

The impedance point level sensor of claim 8, wherein the metallisation is situated in a depression such that a surface free of discontinuities with a material surrounding the metallisation results.