Pulsed Mechanical Effect Detection in Plant Components

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Solution Overview

Problem

Existing methods for detecting pulse-like mechanical actions on plant parts, such as loose parts carried by gas turbines, face challenges in distinguishing these events from high and temporally varying background noise, leading to false alarms and missed detections due to the high operating noise levels.

Innovation Solution

A method involving continuous recording of operating noise with sensors, processing the measurement signals through mathematical transformations, and using an evaluation function derived from Fourier transforms, combined with adaptive quantile-based averaging to enhance signal detection and reduce noise interference, allowing for the reliable identification of pulse-like mechanical effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors continuously record operating noise to detect pulse-like mechanical actions, then detection capability is improved, but false alarms increase due to high background noise levels

Engineering Contradiction:
Improvedetection capabilityVSAvoidfalse alarm rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transforms the measurement signal from time domain to frequency domain using Fourier transformation, changing the parameter representation from amplitude over time to frequency spectrum. This allows identification of characteristic frequency patterns that distinguish impulse events from background noise, resolving the contradiction between detection sensitivity and false alarm rate

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system continuously monitors the frequency spectrum and dynamically compares current spectral characteristics against reference patterns. This feedback mechanism enables real-time distinction between genuine impulse events and background noise variations, maintaining high detection accuracy while minimizing false alarms

Inventive Principle:
Principle #23Feedback

2Loss of energy

If band or high-pass filtering is applied to improve signal-to-noise ratio, then background noise is reduced, but impulse-like events may be attenuated or distorted

Engineering Contradiction:
Improvenoise levelVSAvoidimpulse detection accuracy
Core Design Contradiction:
Loss of energyVSMeasurement precision

Solution Approach 1:

Instead of filtering in the time domain, the patent transitions to frequency domain analysis using Fourier transformation. This dimensional change allows selective identification and evaluation of impulse characteristics in the frequency spectrum without applying time-domain filters that would distort the impulse signal itself

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

3Loss of energy

If simple averaging of measurement signals is used to reduce noise, then noise suppression is achieved, but rapid noise level changes cause false alarms

Engineering Contradiction:
Improvenoise suppressionVSAvoidfalse alarm rate during noise transitions
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system pre-calculates and stores reference frequency spectra representing normal operating conditions before impulse events occur. During monitoring, current spectra are compared against these pre-established references, enabling rapid distinction between genuine impulses and noise transitions without requiring complex real-time adaptive averaging

Inventive Principle:
Principle #10Preliminary action

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 approach effectively differentiates burst signals from background noise, enabling accurate detection of pulse-like mechanical events even during high noise conditions, such as turbine humming, thereby preventing false alarms and ensuring timely detection of potential damage.

Implementation Method 1

A plurality of measured value pickups or sensors 4, in particular piezoelectric acceleration pickups, are arranged on a plant part 2

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the absolute value A(f i ,t j )) of the transform of the measurement signal (M) is determined in time steps of time windows that follow one another in time using specified parameters of a mathematical transformation rule

Methodology Applied
Scientific EffectFourier transformation:

Data Source

PatentEP1979724B1Method and device for detecting a pulsed mechanical effect on a plant component
Publication Date: 2012.03.21 AREVA GMBH
  • EP1979724B1 patent drawingFigure 1~2
  • EP1979724B1 patent drawingFigure 3~4
  • EP1979724B1 patent drawingFigure 5~6

AI summary

The invention relates to a method and device for detecting a pulsed mechanical effect on a plant component (2), whereby an operating noise in the plant component (2) is continuously recorded by means of a sensor (4) which is arranged on the plant component (2) and converted by the above into a measured signal (M) which is subjected to a mathematical transformation. According to the invention, a sliding mean is calculated by determining the quantiles from the determined transformations and the evaluation function (K(t)), which displays the application of a pulsed mechanical effect on the plant component (2), is derived from said sliding mean.