Guided Wave Radar Level Gauge with Multi-Frequency Dielectric Compensation

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Solution Overview

Problem

Radar level gauge systems face challenges in accurately determining filling levels in tanks with varying propagation properties, as existing solutions require reference reflectors that reduce sensitivity.

Innovation Solution

A guided wave radar level gauge system using a transmission line probe configured to operate in two different frequency ranges, with distinct propagation velocities dependent on the dielectric constant of the surrounding medium, allowing for accurate filling level determination without reference reflectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If reference reflectors are provided at known positions along the transmission line probe to compensate for propagation velocity variations, then measurement precision is improved, but device complexity increases and sensitivity is reduced due to signal reflection losses

Engineering Contradiction:
Improvefilling level determination accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the operating frequency parameter of the electromagnetic signals. By using two different frequency ranges, the system can determine propagation velocities at different frequencies and calculate the dielectric constant of the surrounding medium, thereby compensating for propagation velocity variations without requiring reference reflectors.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts and eliminates the reference reflectors from the system. Instead of using reference reflectors to determine propagation velocity, the system uses multi-frequency signal propagation characteristics to calculate the dielectric constant and derive propagation velocity information, thus removing the need for additional reference reflector components.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If reference reflectors are provided to compensate for propagation velocity variations, then measurement precision is improved, but sensitivity is reduced due to signal reflection

Engineering Contradiction:
Improvefilling level determination accuracyVSAvoidsystem sensitivity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses parameter changes by operating at two different frequency ranges. By analyzing the propagation characteristics at these different frequencies, the system can calculate the dielectric constant and compensate for propagation velocity variations without the signal loss associated with reference reflectors, thereby maintaining sensitivity.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multi-frequency propagation is used to compensate for dielectric constant variations, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvefilling level determination accuracyVSAvoidtransceiver complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by using the same transmission line probe and transceiver for both single-frequency and multi-frequency operations. The system can operate in different frequency ranges using the same hardware infrastructure, reducing the need for separate dedicated components for each frequency range.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables accurate filling level measurement in tanks with unknown and non-uniform dielectric constants, compensating for probe contamination and vapor effects, while maintaining system sensitivity.

Implementation Method 1

the transmission line probe being configured to guide electromagnetic signals in the first frequency range with a first propagation velocity exhibiting a first dependence on a dielectric constant of the surrounding medium, and guide electromagnetic signals in the second frequency range with a second propagation velocity exhibiting a second dependence, different from the first dependence, on the dielectric constant of the surrounding medium

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Implementation Method 2

a first propagation velocity exhibiting a first dependence on a dielectric constant of the surrounding medium

Methodology Applied
Scientific EffectDielectric constant effect: Dielectric Permittivity

Implementation Method 3

The electromagnetic signals are subsequently reflected at the surface of the product, and the reflected signals are received by a receiver or transceiver comprised in the radar level gauge system

Methodology Applied
Scientific EffectElectromagnetic signal reflection: Reflection

Implementation Method 4

the distance to the surface of the product is generally determined based on the time between transmission of an electromagnetic signal and receipt of the reflection thereof

Methodology Applied
Scientific EffectTime-of-flight measurement: Time of Flight

Data Source

PatentEP2901111B1Guided wave radar level gauge system with dielectric constant compensation through multi-frequency propagation
Publication Date: 2021.10.27 ROSEMOUNT TANK RADAR
  • EP2901111B1 patent drawingFigure 1a~1b
  • EP2901111B1 patent drawingFigure 2a~3
  • EP2901111B1 patent drawingFigure 4~5

AI summary

The present invention relates to a method of determining a filling level of a product contained in a tank by propagating a first transmitted electromagnetic signal in a first frequency range and a second transmitted electromagnetic signal in a second frequency range different from the first frequency range along a transmission line probe towards a surface of the product in the tank, receiving a first reflected electromagnetic signal in the first frequency range and a second reflected electromagnetic signal in the second frequency range, and determining the filling level based on a time-of-flight of the first reflected electromagnetic signal and a difference in time-of-flight of the first reflected electromagnetic signal and the second reflected electromagnetic signal.