Fill Level Measuring Device with Spatially Remote Probe

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Capacitive fill level sensors face limitations in high-frequency operations due to temperature constraints, measurement accuracy issues, and interference from high-frequency resonance behavior and parasitic capacities in existing designs.

Innovation Solution

Measuring voltage and current directly at the probe with low-ohm, self-contained lines and using diodes to determine temperature, allowing for temperature compensation and reducing interference from standing waves and parasitic capacities, with a control unit connected via partially screened lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If capacitive fill level sensors operate at high frequencies above 100 MHz, then measurement speed and response time improve, but resonance behavior worsens and measurement accuracy deteriorates

Engineering Contradiction:

Improvemeasurement speedVSAvoidmeasurement accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The device separates the sensor probe from the control unit into distinct spatial locations. The probe operates at high frequencies for fast measurement, while the control unit processes signals at lower frequencies, eliminating resonance issues from the measurement path.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A transmission line serves as an intermediary between the high-frequency probe and the control unit. This mediator transfers measurement data while isolating the control unit from high-frequency resonance effects.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If semiconductor control components are used, then device integration and complexity are reduced, but maximum operating temperature is limited to 85° C.

Engineering Contradiction:

Improvecontrol unit integrationVSAvoidoperating temperature

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

The control unit containing temperature-sensitive semiconductor components is spatially separated from the probe that operates in high-temperature environments. This allows the probe to withstand temperatures above 85° C while the control unit remains protected.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The transmission line acts as a thermal and electrical intermediary, allowing signal transmission while preventing heat transfer from the high-temperature probe environment to the temperature-sensitive control unit.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Weight of moving object

If measurement lines are made long to connect probe and control unit, then spatial separation is achieved, but voltage drop and interference increase

Engineering Contradiction:

Improvespatial separationVSAvoidsignal integrity

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent replaces traditional long electrical connection lines with a wireless or short-range communication interface between probe and control unit, eliminating voltage drop and interference issues associated with long cables.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses dynamic signal processing and compensation techniques to maintain signal integrity over the transmission distance, adapting to changing electrical characteristics of the connection medium.

Inventive Principle:

Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach maintains measurement accuracy at high operating frequencies, extends the operating temperature range, and minimizes interference from parasitic capacities and standing waves, enabling reliable fill level determination.

Implementation Method 1

a control unit (1) which contains a high frequency generator (4) for the generation of a transmission signal (S)

Methodology Applied

Scientific EffectHigh frequency signal generation:

Implementation Method 2

the voltage and the current are measured directly at the probe

Methodology Applied

Scientific EffectVoltage measurement:

Implementation Method 3

Capacitive fill level sensors have been used for a long time both as limit switches as well as for media determination

Methodology Applied

Scientific EffectCapacitive sensing: Capacitance

Implementation Method 4

the high frequencies signals are rectified, filtered, and transmitted as very low frequency signals or direct voltage to a control unit

Methodology Applied

Scientific EffectRectification:

Implementation Method 5

a first amplifier (5a), a second amplifier (5b)

Methodology Applied

Scientific EffectSignal amplification:

Data Source

PatentUS9523598B2Fill level measuring device

Publication Date: 2016.12.20 IFM ELECTRONIC GMBH

AI summary

Fill level measuring device having a control unit, which contains a high-frequency generator for generating a transmission signal, an amplifier, an amplifier and an evaluation unit, and a spatially remote probe, which contains a measuring impedance, a reference impedance, a first rectifier and a second rectifier, as well as a connecting line between the control unit and the probe, wherein the rectifier detects the voltage of the transmission signal in the probe, and this voltage is transmitted to the control unit as a first DC voltage signal, and the rectifier converts the probe current in the probe into a second DC voltage signal via measuring resistors, and both signals are supplied to the control unit for the purpose of determining the fill level, wherein the rectifiers are thermally coupled to one another.