Non-Invasive Acoustic Conduit Sensor for Deposition and Level Detection

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Solution Overview

Problem

Existing methods for detecting deposition layers in conduits conducting liquids are often inaccurate due to external parameters such as temperature changes, sludge layer thickness, and fluid flow, leading to unreliable measurements.

Innovation Solution

A device comprising a transmitter and receiver configured to generate and receive Lamb waves or Lamb-Rayleigh waves on the conduit's sidewall, converting them into volume acoustic waves in the medium, with an evaluation unit to detect deposition layers and liquid levels by analyzing signal amplitudes and transmission times, allowing for sub-mm thickness detection and flow-independent measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional acoustic sensing methods are used to detect deposition layers in conduits, then the measurement can be performed non-invasively, but the measurement accuracy deteriorates due to sensitivity to external parameters such as temperature changes, sludge layer thickness, and fluid flow

Engineering Contradiction:
Improvenon-invasive measurementVSAvoidmeasurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The acoustic signal path is segmented into multiple distinct components: Lamb waves propagating in the conduit wall, bulk acoustic waves propagating through the fluid medium, and surface waves at the fluid-deposition interface. Each component carries specific information about different aspects of the system, allowing selective analysis that is insensitive to certain external parameters.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method utilizes changes in acoustic wave parameters (amplitude, arrival time, frequency content) as the conduit fills with fluid or develops deposition layers. By monitoring these parameter changes over time, the system can detect deposition thickness and fluid level while compensating for the effects of temperature and flow conditions.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a single acoustic signal is used for detection, then the device complexity is reduced, but the ability to distinguish between different measurement targets (deposition layer vs. fluid level) deteriorates

Engineering Contradiction:
Improvedevice structureVSAvoiddetection specificity
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system employs periodic excitation signals at multiple frequencies to generate different types of acoustic waves. By analyzing the periodic responses at various frequencies, the system can distinguish between deposition layer detection and fluid level detection using the same physical transducers, maintaining simple device structure while achieving high detection specificity.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If internal sensors are inserted into the conduit for direct measurement, then the measurement accuracy is improved, but the risk of contamination and production impairment increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidcontamination risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The conduit wall itself serves as an intermediary medium that transmits acoustic information from the internal deposition layers and fluid medium to external sensors. This allows indirect measurement of internal conditions through the wall, maintaining high measurement accuracy while eliminating the need for internal sensor insertion and associated contamination risks.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces direct mechanical contact sensors with acoustic wave-based detection. Acoustic waves can penetrate the conduit wall and interact with the internal medium without requiring physical contact, substituting a non-contact mechanical field measurement approach that avoids contamination while maintaining measurement precision.

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

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 provides accurate and reliable detection of deposition layers and liquid levels, even in flowing media, with the ability to monitor existing conduit systems without internal sensor insertion, enabling continuous monitoring and prevention of production impairments or contamination.

Implementation Method 1

the transmitter is configured for evoking Lamb waves or Lamb-Rayleigh waves in the sidewall of the conduit

Methodology Applied
Scientific EffectLamb waves: Surface Acoustic Wave

Implementation Method 2

the transmitter is configured for evoking Lamb waves or Lamb-Rayleigh waves in the sidewall of the conduit

Methodology Applied
Scientific EffectLamb-Rayleigh waves: Surface Acoustic Wave

Implementation Method 3

a portion of the Lamb waves or Lamb-Rayleigh waves is converted into volume acoustic waves in the medium

Methodology Applied
Scientific EffectVolume acoustic waves:

Implementation Method 4

a receiver for receiving acoustic waves evoked by the transmitter

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3710795B1Device and method for detecting deposition layers in a conduit conducting a liquid or a soft medium and/or for level detection
Publication Date: 2024.04.03 HOCHSCHULE FUER ANGEWANDTE WISSENSCHAFTEN FACHHOCHSCHULE COBURG
  • EP3710795B1 patent drawingFigure 1
  • EP3710795B1 patent drawingFigure 2
  • EP3710795B1 patent drawingFigure 3

AI summary

Device for detecting deposition layers in a conduit conducting a liquid or a soft medium and/or for level detection, the device comprising a transmitter (31) for generating acoustic waves (SSAW, AWM); a receiver (32) for receiving acoustic waves (SSAW, AWM) evoked by the transmitter (31); a holder (20) carrying the transmitter (31 ) and the receiver (32), wherein the holder (20) is configured to be detachably connected to the conduit (4) in such a way that the transmitter (31) and the receiver (32) are arranged on an outer side of a sidewall (41) of the conduit (4), wherein a single transmitter- receiver unit provides both the transmitter (31) and the receiver (32) or the transmitter (31) and the receiver (32) are separate units arranged in a distance from one another at the holder (20) in such a way that the transmitter (31) and the receiver (32) are located in a common plane extending at least essentially perpendicular to a longitudinal axis of the conduit (4) when the holder (20) is connected to the conduit (4); and an evaluation unit for evaluating signals generated by the receiver (32) upon receipt of acoustic waves (SSAW, AWM) evoked by the transmitter (31) to detect a deposition layer (6) on an inner surface (411) of the sidewall (41) of the conduit (4) and/or for detecting whether the level (51) of the medium (5) is below a predetermined value. According to the invention the receiver (32) is configured for receiving first acoustic waves excited by the transmitter (31) in the sidewall (41) of the conduit (4) and propagating in the sidewall (41) and for receiving second acoustic waves evoked by the transmitter (31) and propagating at least partially through the medium (5), wherein the evaluation unit is configured to detect a deposition layer (6) on the inner surface (411) of the sidewall (41) of the conduit (4) and/or whether the level (51) of the medium (6) is below a predetermined value by evaluating first signals generated by the receiver (32) upon receipt of the first acoustic waves and second signals generated by the receiver (32) upon receipt of the second acoustic waves. The invention also relates to a method for detecting deposition layers in a conduit conducting a liquid or a soft medium and/or for level detection.