Acoustic Emission Crystal Self-Test Circuit

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Solution Overview

Problem

Existing methods for verifying the proper installation of acoustic emission (AE) piezoelectric crystals require additional components and equipment, such as external signal sources or secondary crystals, which increase setup time and complexity.

Innovation Solution

A self-test circuit comprising a voltage source, controller, pulse waveform input, analyzer, and multiplexer IC that excites and acquires signals from the AE crystal, allowing for self-validation of attachment without external sensors or signal generators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external signal sources or secondary sensors are used to verify proper installation of AE crystals, then measurement reliability is improved, but device complexity and quantity of components increase

Engineering Contradiction:
Improveinstallation verification reliabilityVSAvoidtesting system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the signal generation and signal acquisition functions into a single integrated circuit. The multiplexer switches between connecting the AE crystal to the signal generator output and connecting it to the analyzer input, eliminating the need for separate external signal sources and secondary sensors while maintaining reliable installation verification capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated circuit performs multiple functions: it generates test signals, switches between test and measurement modes, amplifies weak signals, and analyzes the output. This multi-functional approach replaces what previously required multiple separate components, reducing system complexity while maintaining verification reliability.

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

2Measurement precision

If external signal sources or secondary sensors are used to test AE crystal installation, then measurement accuracy is improved, but loss of time increases due to additional setup equipment

Engineering Contradiction:
Improveinstallation verification accuracyVSAvoidsetup time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The signal generation and analysis capabilities are built into the system beforehand, eliminating the need for preliminary setup of external equipment. The multiplexer is pre-configured to switch between test and measurement modes, allowing immediate verification without additional setup time while maintaining measurement accuracy.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If additional components are used for AE crystal testing, then reliability of detection is improved, but ease of operation deteriorates due to extra setup requirements

Engineering Contradiction:
Improvedetection reliabilityVSAvoidtesting procedure simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

By merging the signal generation, switching, amplification, and analysis functions into a single integrated circuit, the system eliminates multiple separate components that would complicate operation. The unified design allows simple mode switching via the multiplexer while maintaining reliable detection capability.

Inventive Principle:
Principle #5Merging (Combining)

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 repeatable and efficient testing of AE crystals attached to bearings or machine enclosures, reducing the need for additional equipment and streamlining the validation process by using a built-in signal injection and acquisition configuration.

Implementation Method 1

Acoustic emission (AE) piezoelectric crystals and vibration crystals are secured directly to one of a bearing, a bearing housing, or the associated machine

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

Acoustic emission (AE) piezoelectric crystals and vibration crystals are secured directly to one of a bearing, a bearing housing, or the associated machine

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2976633B1Sensor self-test
Publication Date: 2021.08.04 AB SKF SKF PATENT DEPARTMENT
  • EP2976633B1 patent drawingFigure 1
  • EP2976633B1 patent drawingFigure 2
  • EP2976633B1 patent drawingFigure 3

AI summary

A crystal self-test circuit (100, 200) is used to self-test either an acoustic emission crystal (110) or a vibration crystal (211) installed onto one of a bearing (150), a bearing housing (160), and a machine (170). A crystal self-test circuit (100, 200) includes a multiplexer IC (120, 220), which toggles between a pulse injection configuration and a signal collection configuration. In the pulse injection configuration, the multiplexer IC (120, 220) provides signal communication between a crystal self-test input (122, 222) and the sensing emission crystal (110, 211). In the signal collection configuration, the multiplexer IC (120, 220) provides signal communication between the sensing emission crystal (110, 211) and a signal analyzer (126, 226). In operation, the multiplexer IC (120, 220) applies a waveform (preferably a square wave) to the sensing emission crystal (110, 211) over a predetermined time period. The multiplexer IC (120, 220) then toggles to collect the output waveform from the sensing emission crystal (110, 211) and forwards the output waveform to the signal analyzer (126, 226). The output signal can be amplified by a signal amplifier (130, 231).