Piezoelectric Drain Stratification Detection via Acoustic Reflection

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Solution Overview

Problem

Existing installations for detecting stratification around drains and outlets on building roofs are inefficient, as they require channels or openings that risk leakage and expose sensors to environmental damage, cannot directly identify the type of stratification, and may obstruct aesthetic appeal.

Innovation Solution

The use of piezoelectric transducers that generate and measure acoustic waves to detect and calculate reflection coefficients and time delays, combined with weight sensors and a contact medium with suitable acoustic impedance, allows for non-invasive detection and identification of stratification types, such as ice, water, and snow, while preventing direct access and facilitating maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors are mounted on the same side as the layers of ice, snow and water for direct detection, then detection capability is improved, but the sensors are exposed to environmental damage and foreign body intrusion

Engineering Contradiction:
Improvedetection capabilityVSAvoidsensor protection
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The sensor is moved from the conventional position (same side as stratification) to the opposite side of the drain outlet. This dimensional repositioning allows the sensor to detect stratification through the drain structure while being protected from direct exposure to ice, snow, and foreign bodies on the roof surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If channels or openings are made through the base surrounding the drain for sensor installation, then sensor mounting is enabled, but the risk of future leakage increases

Engineering Contradiction:
Improvesensor mountingVSAvoidleakage risk
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The drain outlet structure serves multiple functions: it acts as both the drainage pathway and the mounting substrate for the sensor. The sensor is mounted on the outer surface of the drain outlet, utilizing the existing structural element for both its primary function (drainage) and the sensing function, thereby avoiding additional channels or openings that would compromise waterproofing.

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

3Ease of manufacture

If protrusions of components are used for sensor mounting, then sensor installation is achieved, but aesthetic degradation of the surroundings occurs

Engineering Contradiction:
Improvesensor installationVSAvoidaesthetic appearance
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The sensor mounting location is carefully selected on the drain outlet structure to be minimally visible from aesthetic viewpoints. The sensor is positioned on the outer surface of the drain outlet, utilizing existing structural features for mounting without adding protruding elements that would compromise the visual appearance of the roof and surrounding area.

Inventive Principle:
Principle #3Local quality

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 solution enables efficient and accurate detection of stratification without direct access, reducing the risk of damage and aesthetic issues, while allowing for effective identification and measurement of layer thicknesses and foreign objects, thereby preventing blockages and ensuring proper drainage.

Implementation Method 1

Detection, identification and thickness of said layers located above each of the piezoelectric transducers are achieved by generation and transmission of acoustic waves, followed by measurements of tranducer signals caused by reflected, acoustic waves in the interfaces and surfaces of the layers

Methodology Applied
Scientific EffectAcoustic wave reflection: Reflection

Implementation Method 2

The installation comprises a set of piezoelectric transducers

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

For such measurements, i.e. identification and measurement of thickness, it is advantageous to select a contact medium with acoustic impedance close to the acoustic impedances of the layers to be measured

Methodology Applied
Scientific EffectAcoustic impedance matching:

Data Source

PatentEP2181439B1Installation for detection and measuring of stratification around a drain
Publication Date: 2020.03.18 JOHNSEN
  • EP2181439B1 patent drawingFigure 1~2
  • EP2181439B1 patent drawingFigure 3

AI summary

An installation for detection and measurement of stratification around drains/outlets (1) on building roofs for drainage of liquids, in particular environmentally induced stratification (6, 7) such as water and/or ice, comprising at least one sensor and at least one control and measuring system (23). The piezoelectric transducers (2) transmit acoustic waves into the formed layers (6, 7) via a suitable contact medium (5) and a suitable sealing compound (4). Each of the piezoelectric transducers (2) with sealing compound (4) may alternatively be encapsulated into a protection case (3), which again is mounted/installed underneath the contact medium (5). By measuring reflection coefficients and time delays between the transmitted acoustic waves and their reflections from interfaces and surfaces of the stratifications, layer information such as detection, identification and thicknesses may be achieved. The installation may preferably also comprise at least one weight system to complement said layer information, give additional information such as amount of snow (8, 34) and detect undesirable intrusion of foreign matters (10). A preferred embodiment is to integrate a heating system (26) with the said installation, where engagements and disengagements of said system (26) depend on the measurement results from the transducers (2) and the weight systems (9, 35).