Magnetostriction Sensor for Compressor Tie-Bolt Stress Monitoring

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Solution Overview

Problem

Existing methods for measuring tie-bolt strain in hyper reciprocating compressors are impractical due to high pressures, invasive techniques, and limitations of resistive strain gauges such as costly modifications, signal-to-noise ratio issues, and mechanical failures.

Innovation Solution

A magnetostriction-based sensor system that measures changes in magnetic permeability to estimate mechanical stress and pressure in hyper reciprocating compressors, providing a non-invasive, contactless monitoring solution with improved signal quality and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional intrusive pressure measurement methods are used, then pressure can be measured directly, but the compressor structure must be modified by drilling holes and resealing, which is complex and time-consuming

Engineering Contradiction:
Improvepressure measurementVSAvoidcompressor structure modification
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical intrusive pressure measurement with a magnetostriction-based sensing system that uses magnetic field interactions. The sensor measures tie-bolt strain through changes in magnetic permeability without requiring physical contact or structural modification, thereby substituting a mechanical measurement approach with a magnetic field-based approach.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetostriction sensor as an intermediary device that indirectly measures pressure by monitoring tie-bolt strain through magnetic permeability changes. This intermediary measurement approach avoids the need for direct pressure sensing inside the compressor, eliminating the need for structural modifications while still providing accurate pressure data.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If resistive strain gauges are used on modified tie-bolts, then strain measurement is possible, but costly modifications and installation time are required

Engineering Contradiction:
Improvestrain measurementVSAvoidinstallation cost and time
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces resistive strain gauges that require mechanical bonding and tie-bolt modification with a magnetostriction-based sensor system. The magnetostriction sensor uses magnetic field interactions to measure strain without requiring adhesive bonding or structural modification, thereby eliminating costly and time-consuming installation procedures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetostriction sensor acts as an intermediary that measures tie-bolt strain through magnetic permeability changes without direct physical contact or modification. This intermediary approach eliminates the need for mechanical attachment methods used in traditional strain gauge installation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If clamp-on style resistive strain gauges are used, then removal is possible, but signal-to-noise ratio is poor and mechanical failure occurs

Engineering Contradiction:
ImproveremovabilityVSAvoidsignal quality and connection integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces mechanical clamp-on resistive strain gauges with a magnetostriction-based sensor system that uses magnetic field interactions. This substitution eliminates the mechanical connection issues that cause signal noise and connection failure, while maintaining the ability to remove and reposition the sensor without structural modification.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetostriction sensor serves as a non-contact intermediary that measures strain through magnetic permeability changes. This intermediary approach eliminates the mechanical bonding interface that is prone to failure and noise in traditional strain gauges, thereby improving signal quality and connection reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If tie-bolts are modified with resistive strain gauges, then monitoring capability is achieved, but during maintenance the tie-bolt may be replaced or misplaced, losing monitoring ability

Engineering Contradiction:
Improvecompressor monitoringVSAvoidmaintenance flexibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The magnetostriction sensor acts as a standalone intermediary device that measures tie-bolt strain through magnetic permeability changes without being permanently attached to the tie-bolt. This allows the sensor to remain on the compressor structure while the tie-bolt can be replaced during maintenance, maintaining monitoring capability without being tied to specific hardware components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the integrated strain gauge-tie-bolt system with a separate magnetostriction-based sensing system. This substitution decouples the monitoring capability from the tie-bolt hardware, allowing maintenance personnel to replace tie-bolts without affecting the monitoring system's functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 magnetostriction-based sensor system offers reliable, non-invasive pressure monitoring with enhanced signal-to-noise ratio and frequency response, reducing maintenance challenges and maintaining connection integrity, even in high-pressure environments.

Implementation Method 1

The magnetostriction-based sensor is configured to measure a change in magnetic permeability of a target material of the reciprocating compressor

Methodology Applied
Scientific EffectMagnetostriction: Magnetostriction

Data Source

PatentEP3084215B1Systems and methods for determining mechanical stress of a compressor
Publication Date: 2020.08.05 GENERAL ELECTRIC CO
  • EP3084215B1 patent drawingFigure 1
  • EP3084215B1 patent drawingFigure 2~4
  • EP3084215B1 patent drawingFigure 5

AI summary

A system for determining mechanical stress of a compressor is provided. The system includes a reciprocating compressor. The system also includes a magnetostriction sensor coupled to the reciprocating compressor and configured to measure a change in magnetic permeability of a target material of the reciprocating compressor. Furthermore, the system includes a processor configured to convert the measured change in the magnetic permeability of the target material into an estimated mechanical stress under which the target material is exposed.