Radar Fill Level Sensor Signal Generation Component Separation

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Solution Overview

Problem

High-frequency radar fill level measuring systems face challenges with signal quality due to small waveguide diameters, mechanical tolerances, and frequency-dependent propagation times, making it difficult to maintain pressure-tight and diffusion-tight separation while achieving impedance matching and avoiding signal dispersion.

Innovation Solution

The system separates the electronic device into two independent components, with a signal generation component inside the container and a separate component outside, connected by a communication device with a pressure-tight and diffusion-tight separating element, allowing for different design conditions and avoiding high-frequency signal transmission issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If waveguide diameter is reduced to accommodate higher frequencies, then higher-frequency signals can be transmitted, but mechanical tolerances have a stronger effect on signal quality

Engineering Contradiction:
Improvesignal qualityVSAvoidmechanical tolerances
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical waveguide system with an optical fiber communication system. Instead of transmitting high-frequency electromagnetic signals through a waveguide, the system transmits modulated optical signals through an optical fiber. This substitution eliminates the mechanical tolerance issues that plague high-frequency waveguides, as optical fibers are not sensitive to the same dimensional tolerances. The optical fiber provides a robust transmission medium that maintains signal quality without requiring precision mechanical tolerances.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the transmission parameter from electromagnetic frequency to optical wavelength. By modulating the optical signal with the radar control signals, the system transfers the information to a different physical domain (optical instead of electromagnetic). This parameter change allows the system to achieve high-frequency radar operation without the mechanical tolerance constraints that limit waveguide performance at high frequencies.

Inventive Principle:
Principle #35Parameter changes

2Length of stationary object

If waveguide length is increased to extend signal transmission, then transmission distance is improved, but frequency-dependent propagation times cause signal dispersion

Engineering Contradiction:
Improvetransmission distanceVSAvoidsignal dispersion
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent replaces the electromagnetic waveguide transmission system with an optical fiber transmission system. Optical fibers exhibit much lower frequency-dependent propagation characteristics compared to waveguides. The modulated optical signals travel through the optical fiber with minimal dispersion, allowing for extended transmission distances without the signal degradation caused by frequency-dependent propagation times in waveguides.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the transmission medium parameter from metallic waveguide to dielectric optical fiber. This parameter change fundamentally alters the propagation characteristics, eliminating the frequency-dependent phase velocity issues that cause signal dispersion in waveguides. The optical fiber provides frequency-independent propagation for the modulated signals, maintaining signal integrity over long distances.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If signal transmission device is integrated on chip, then high-frequency signals can be generated, but pressure-tight and diffusion-tight separation becomes more difficult

Engineering Contradiction:
Improvehigh-frequency signal generationVSAvoidpressure-tight separation
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the radar system into distinct functional modules: the signal generation and transmission components (antenna and associated electronics) are separated from the control and evaluation electronics. The integrated high-frequency signal generation remains in the antenna module, which can be pressure-tight sealed, while the lower-frequency control signals are generated by separate electronics that can be located in non-pressure-tight environments. The optical fiber provides the interface between these segmented modules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an optical fiber as an intermediary between the pressure-tight antenna module and the non-pressure-tight control electronics. This intermediary allows the system to maintain pressure-tight separation while still enabling communication and control. The optical fiber acts as a barrier to pressure and diffusion while transmitting the modulated control signals, thus resolving the contradiction between maintaining pressure-tight separation and enabling high-frequency signal generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration enables the use of higher-frequency signals with improved signal quality and easier impedance matching, reducing the impact of mechanical tolerances and frequency-dependent effects, while maintaining necessary separation and explosion protection.

Implementation Method 1

The invention relates to a fill level measuring system working according to the radar principle for measuring a fill level of a medium located in a container

Methodology Applied
Scientific EffectRadar principle: Radar

Implementation Method 2

an electronic device for generating at least one electromagnetic signal to be transmitted by the signal transmission device

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 3

The useful echo signal - i.e. the signal reflected on the surface of the medium - and its transit time are determined

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

a pressure-tight and/or diffusion-tight separating element is provided in the level measuring system

Methodology Applied
Scientific EffectPressure-tight sealing: Physical Containment

Data Source

PatentEP2623944B1Fill level measuring device operating according to the radar principle
Publication Date: 2018.03.07 KROHNE MESSTECHNICK GMBH & CO KG
  • EP2623944B1 patent drawingFigure 1~2
  • EP2623944B1 patent drawingFigure 3~4

AI summary

The system (1) has a multi-part electronic device (3) whose component is arranged as a signal-generating component (7) for generating an electromagnetic signal to be transmitted. The signal-generating component and another component (8) of the electronic device are formed as independent units that are spatially separated from each other. A communication unit (4) is arranged between the signal-generating component and the latter component, and a pressure and/or diffusion-proof separating element (6) is arranged between the latter component and a signal transmitting unit (2). The signal generation component and the signal transmitting unit are configured as a connected unit. The pressure and/or diffusion-proof separating element are configured as a component of the communication unit.