Piezoceramic Sensor Protective Coating for Harsh Environments

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Solution Overview

Problem

Piezoelectric sensors are not adequately designed to operate under high thermal and mechanical stresses, limiting their use in harsh industrial environments where conventional devices fail due to thermal and mechanical stress resistance issues.

Innovation Solution

A signal transduction device with a protective coating made from resin or ceramic materials, incorporating a thermally insulating layer and high-temperature welding pastes, which provides thermal and electrical insulation, and distributes external forces to prevent mechanical stress on the piezoceramic sensor, allowing operation above 200°C and in high-pressure conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If piezoelectric sensors are used in harsh environments, then signal transduction capability is improved, but thermal and mechanical stress resistance deteriorates

Engineering Contradiction:

Improvesignal transduction capabilityVSAvoidthermal and mechanical stress resistance

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The device is divided into distinct functional components: the piezoelectric sensor element and the protective coating layer. This segmentation allows each component to be optimized independently - the sensor for signal transduction and the coating for environmental protection, resolving the contradiction between measurement capability and stress resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A protective coating layer is introduced as an intermediary between the piezoelectric sensor and the harsh environment. This coating acts as a mediator that protects the sensor from thermal and mechanical stress while allowing the sensor to maintain its signal transduction function, thus resolving the contradiction between measurement precision and reliability in harsh conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If protective coating is added to piezoelectric sensor, then thermal and mechanical stress resistance is improved, but device complexity increases

Engineering Contradiction:

Improvethermal and mechanical stress resistanceVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective coating is implemented as a thin film layer that provides environmental protection without adding significant structural complexity. This thin film approach maintains simplicity while achieving the desired protection against thermal and mechanical stress, resolving the contradiction between reliability improvement and device complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

3Strength

If harder material is used for protective coating, then mechanical strength is improved, but sensitivity of piezoelectric sensor deteriorates

Engineering Contradiction:

Improvemechanical strength of protective coatingVSAvoidsensitivity of piezoelectric sensor

Core Design Contradiction:

StrengthVSMeasurement precision

Solution Approach 1:

The elastic modulus of the protective coating is carefully selected to be lower than that of the piezoceramic sensor material. This parameter change ensures that the coating provides mechanical protection while allowing sufficient force transmission to maintain sensor sensitivity, resolving the contradiction between mechanical strength and measurement precision.

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 robust, precise, and reliable operation of piezoelectric sensors in extreme conditions, such as high-temperature and high-pressure applications, by reducing mechanical stress on the sensor and enhancing sensitivity, making it suitable for use in industries like oil extraction and automotive sectors, while also allowing for smaller and cheaper sensor designs.

Implementation Method 1

Piezoelectric sensors exploit the property of some crystalline materials of polarizing themselves generating a potential difference when they are subjected to mechanical deformation

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the use of material for the protective coating with elastic modules smaller than those typical of the piezoceramic materials will imply a damping effect lowering the applied forces to the piezoceramic sensor

Methodology Applied

Scientific EffectDamping: Damping

Data Source

PatentEP3289328B1Signal transduction device

Publication Date: 2023.11.08 ITT ITAL SRL

Figure 1
Figure 2a~2c

AI summary

The signal transduction device (1) comprises at least one piezoceramic sensor (4) supported on a support element (2) and featuring an integral protective coating (16) having properties of mechanical and temperature resistance, said integral protective coating (16) being in direct or indirect contact with said support element (2) perimetrally to said piezoceramic sensor (4) so as to direct a predetermined part of an external compression force acting on said piezoceramic sensor (4) onto an area of the support element (2) surrounding said piezoceramic sensor (4).