Buoyant Part Waveguide for Radar Level Detection

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Solution Overview

Problem

Guided wave radar systems face challenges in accurately detecting liquid levels at the end of a waveguide, particularly with low dielectric constant liquids, as the signal reflection from the liquid is overwhelmed by the reflection from the probe, leading to erratic and unreliable measurements.

Innovation Solution

A modified waveguide design incorporating a probe with a buoyant part and an end weight that produces a secondary signal, allowing for reliable detection of liquid levels by enhancing the reflected signal and accounting for buoyancy and gravity, thereby improving measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a standard waveguide probe is used for level measurement, then the measurement range extends nearly to the bottom of the tank, but the measurement is not reliable at the absolute bottom due to signal reflection being overwhelmed by probe reflection

Engineering Contradiction:
Improvelevel measurement accuracyVSAvoidmeasurement reliability at end of probe
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A buoyant part is introduced as an intermediary element between the probe and the liquid. This buoyant part moves with the liquid level and generates a secondary signal that serves as a mediator to indicate the liquid level position, particularly when the liquid level is within the end signal range of the probe

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system utilizes changes in the physical state and position of the buoyant part as the liquid level changes. The buoyant part's position parameter changes in response to liquid level, and this positional change is converted into a detectable secondary signal parameter that improves measurement reliability

Inventive Principle:
Principle #35Parameter changes

2Length of stationary object

If the probe extends to the bottom of the tank for maximum measurement range, then coverage is improved, but measurement reliability deteriorates due to signal reflection interference at the end of the probe

Engineering Contradiction:
Improveprobe lengthVSAvoidsignal detection reliability
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The buoyant part acts as a mediator that converts the liquid level position into a secondary signal. This intermediary mechanism allows the system to maintain a long probe for maximum range while overcoming the signal interference problem at the probe end by using the buoyant part's position as an additional detection reference

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If conventional level measurement methods are used, then the system structure remains simple, but the ability to detect low liquid levels accurately is insufficient

Engineering Contradiction:
Improvewaveguide structure complexityVSAvoidlow liquid level detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The invention changes the detection parameter by introducing a secondary signal based on the buoyant part's position. This parameter change enables accurate detection of low liquid levels by monitoring the buoyant part's position rather than relying solely on the probe's end signal, which is overwhelmed by reflection interference

Inventive Principle:
Principle #35Parameter changes

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

The solution enables accurate and consistent level measurements even at low liquid levels, reducing measurement errors and providing reliable tracking of fluid levels in storage tanks, especially for liquids with low dielectric constants.

Implementation Method 1

The buoyant part is slidably coupled to the end weight and is configured to move with the level of the process fluid at an end of the probe

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

the position of the target is detectable through time of flight measurements of a signal generated by the signal generator

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 3

guided wave radar system

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 4

a waveguide that includes a probe and a buoyant part. The probe is configured to guide the signal from the transceiver and the plurality of reflected signals to the transceiver

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Data Source

PatentEP3347733B1An apparatus and method to detect liquid material at the end of the waveguide in a guided wave radar system
Publication Date: 2020.11.04 HONEYWELL INTERNATIONAL INC
  • EP3347733B1 patent drawingFigure 1
  • EP3347733B1 patent drawingFigure 2A~2C
  • EP3347733B1 patent drawingFigure 3A~3F

AI summary

An apparatus (100) includes a transceiver (105) configured to generate a signal (110) and receive a plurality of reflected signals (130) for measurement of a level (145) of a process fluid (120) in a tank (155). The apparatus also includes a waveguide (115) comprising a probe (185) and a buoyant part (360). The probe is configured to guide the signal from the transceiver and the plurality of reflected signals to the transceiver. The buoyant part is configured to move with the level of the process fluid at an end (125) of the probe and produce a secondary signal (255) representing the level of the process fluid when a level signal (220) of the process fluid is within an end signal (235) representing the end of the probe.