Single-Beam Radar Flow Sensor for Open Channel Measurement

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Solution Overview

Problem

Existing non-contact open channel flow measurement systems face inaccuracies due to the use of distinct energy beams for measuring fluid level and velocity, leading to errors in volumetric flow calculations, especially when hydraulic steps or varying cross-sectional areas are present.

Innovation Solution

A non-contact flow sensor system utilizing a single energy beam to measure both fluid level and velocity, with the beam angled between 25 and 45 degrees above the fluid surface, employing radar-based technology and spectral tapering to reduce leakage and aliasing, and using pulse diversity to modulate the frequency, allowing for accurate bulk flow calculation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If distinct energy beams are used for measuring fluid level and velocity, then both parameters can be measured simultaneously, but measurement precision deteriorates due to computational inaccuracies and hydraulic step interference

Engineering Contradiction:
Improvevolumetric flow measurement accuracyVSAvoidmultiple energy beams required
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines level and velocity measurements into a single energy beam system. The radar transceiver sends a single beam that performs both functions through different signal processing techniques, eliminating the need for separate beams and reducing computational complexity while maintaining measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single energy beam is designed to perform multiple functions: it measures both fluid level (through time-of-flight calculation) and fluid velocity (through Doppler shift analysis). This multi-functional approach replaces the need for specialized separate beams for each measurement type.

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

2Device complexity

If a single energy beam is used to measure both fluid level and velocity, then device complexity is reduced, but measurement precision may deteriorate due to signal interference and leakage

Engineering Contradiction:
Improvesingle energy beam systemVSAvoidsignal detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the signal processing into distinct components: one pathway processes time-of-flight information for level measurement, while another pathway processes Doppler shift information for velocity measurement. This segmentation within the single beam system prevents signal interference and maintains precision for both parameters.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses spectral tapering as an intermediary technique to reduce leakage and aliasing effects in the signal processing. This intermediary processing step enhances signal clarity and maintains measurement accuracy despite the constraints of using a single energy beam.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If beam angle is optimized between 25 and 45 degrees, then measurement accuracy is improved, but device adaptability to different channel configurations is reduced

Engineering Contradiction:
Improvebulk flow calculation accuracyVSAvoidchannel configuration flexibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent optimizes the beam angle parameter to between 25 and 45 degrees relative to the fluid surface. This specific angular range minimizes interference from hydraulic steps and improves the accuracy of bulk flow calculations by optimizing the interaction between the beam and fluid surface characteristics.

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 system provides more accurate measurements by minimizing computational inaccuracies and reducing the impact of hydraulic steps and varying cross-sectional areas, ensuring precise volumetric flow determination with a single beam contact point.

Implementation Method 1

a non-contact flow sensor system utilizing a single energy beam to measure both fluid level and velocity, with the beam angled between 25 and 45 degrees above the fluid surface, employing radar-based technology

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

The Doppler frequency shift between the directed and reflected signals is used as a measure of the velocity of the fluid surface

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 3

A typical acoustic beam may utilize directed ultrasonic energy

Methodology Applied
Scientific EffectUltrasonic: Ultrasound

Implementation Method 4

the Doppler frequency shift between the directed and reflected signals is used as a measure of the velocity of the fluid surface

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 5

what is measured is the time delay between a transmitted energy pulse and its subsequent reflection from the fluid surface. From this delay, the vertical distance ('range') between the sensor and the fluid surface is determined

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP3460417B1Single-beam radar level and velocity sensing
Publication Date: 2020.11.25 HACH
  • EP3460417B1 patent drawingFigure 1
  • EP3460417B1 patent drawingFigure 2
  • EP3460417B1 patent drawingFigure 3

AI summary

An embodiment provides a method for measuring velocity and depth of fluid flow in a channel, including: transmitting, using a transmitter, directed energy comprising a single energy beam slant-wise toward a surface of a fluid in a fluid channel producing a plurality of reflections, wherein the transmitting comprises modulating a frequency associated with the single energy beam; detecting, at a receiver, received signals from the plurality of reflections; and determining, based upon differences between parameters of the transmitted single energy beam and parameters of the received signals, the velocity of the fluid and the depth of the fluid. Other embodiments are described and claimed.