Contactless Flow Sensor with Decoupled Piezoelectric Ceramics

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Solution Overview

Problem

Existing contactless flow measurement devices for fluids in flexible tubes with diameters below 12 mm suffer from signal interference due to physically separated transmitter/receiver transducers, limited applicability to smaller tube sizes, and sensitivity to temperature variations affecting viscosity.

Innovation Solution

Integration of decoupled piezoelectric ceramics with an optimized width/thickness ratio within a compact, modular housing design that includes a temperature sensor and a shielded electronic evaluation system, allowing for improved signal transmission and reception without crosstalk, and accommodating flexible tubes from 3.5 mm diameter through a variable cross-section measuring channel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transmitter/receiver transducers are physically separated in clamp-on sensors, then the device can measure flow in flexible tubes, but signal crosstalk occurs on the connection line between transducers

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidsignal crosstalk

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent integrates the transmitter and receiver transducers into a single sensor housing that clamps onto the tube, eliminating the need for separate transducers connected by cables. This merging of components removes the connection line that caused signal crosstalk, while maintaining the ability to perform contactless flow measurement through the tube wall.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If clamp-on sensors are designed for larger tube diameters, then signal transmission is easier, but measurement of smaller tube sizes (below 12 mm) becomes difficult

Engineering Contradiction:

Improveapplicability to smaller tube sizesVSAvoidmeasurement precision on small tubes

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The sensor housing is designed with a compliant mounting mechanism that can adapt to different tube diameters dynamically. The clamping structure allows the sensor to conform to the tube surface regardless of size, ensuring consistent acoustic coupling and measurement precision across a wide range of tube diameters including those below 12 mm.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent modifies key parameters of the transducer and housing design to optimize performance on small tubes. This includes adjusting the transducer size, modifying the acoustic coupling interface, and tuning the ultrasonic frequency to achieve effective signal transmission through thin-walled small-diameter tubes while maintaining measurement accuracy.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the measuring channel is designed to accommodate various tube diameters, then adaptability increases, but the surface area for coupling sound signals decreases

Engineering Contradiction:

Improverange of usable diametersVSAvoidcoupling surface area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The sensor employs localized acoustic coupling zones with optimized transducer placement and sizing. Instead of attempting to couple across the entire measuring channel width, the patent concentrates the acoustic energy transmission at specific optimal locations on the tube surface, maximizing coupling efficiency while maintaining adaptability to different diameters through the compliant housing design.

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

Enables accurate, non-invasive flow measurement of sound-transparent fluids with enhanced stability and adaptability to varying tube diameters and temperatures, reducing signal interference and improving measurement significance.

Implementation Method 1

measuring cell with ceramics (piezoelectric elements) facing each other diagonally in pairs

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the ultrasonic signals are coupled in the direction of the liquid flow or against it

Methodology Applied

Scientific EffectUltrasonic transmission: Ultrasound

Data Source

PatentUS9016137B2Device for the contactless flow measurement of fluids in flexible tubes

Publication Date: 2015.04.28 SONOTEC ULTRASCHALLSENOSORIK HALLE

AI summary

For flow measurement a device with a compact housing and a fixable hinged cover has a measuring channel for inserting a flexible tube such that it becomes deformed in a defined way. The measuring channel extends over the entire width of the housing. A measuring cell arranged in the center of the measuring channel hasfour ceramics I, II, III, IV, integrated in a sound-decoupled way and facing each other diagonally in pairs, which are placed in lateral parts on the left and on the right of the measuring cell, and a base plate limiting the measuring cell downwards in the direction of an installation space for an electric evaluation system, wherein the base plate also limits the remaining area of the measuring channel from below.