NMR Sensor for Elastomeric Layer Thickness Measurement

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Solution Overview

Problem

Current methods for measuring the thickness and material of multi-component elastomeric products, such as tire tread strips, are inaccurate and time-consuming, leading to out-of-specification products and significant waste due to delayed detection of thickness deviations during production.

Innovation Solution

A method utilizing an NMR sensor with a temperature-resistant permanent magnet and a defined magnetic field gradient to continuously measure the thickness and material of moving elastomeric products, allowing for real-time adjustment of production parameters to maintain specifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical measurement of sampled product is used, then measurement can be performed, but measurement accuracy is low and measuring time is long (about one minute per measuring point)

Engineering Contradiction:
Improvethickness measurement accuracyVSAvoidmeasuring time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces optical measurement methods with NMR (Nuclear Magnetic Resonance) measurement technology. The NMR sensor uses magnetic field gradients to measure layer thicknesses continuously without contact, achieving high precision measurements in real-time as the extruded product moves through the measurement zone, eliminating the slow sampling and optical measurement process.

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

Solution Approach 2:

The NMR measurement system enables continuous measurement of layer thicknesses along the entire length of the moving extruded product, rather than discrete point measurements. The sensor continuously scans the product as it moves, providing ongoing thickness data that can immediately indicate deviations from specifications.

Inventive Principle:
Principle #20Continuity of useful action

2Productivity

If delayed detection of thickness deviations is used, then production continues, but out-of-specification products are produced and scrap material increases

Engineering Contradiction:
Improveproduction continuityVSAvoidscrap material
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The NMR measurement system provides real-time feedback on layer thicknesses during production. When thickness deviations from specifications are detected, the system can immediately signal for process adjustments to be made, preventing the production of out-of-specification products and reducing scrap material while maintaining production continuity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The continuous NMR measurement detects thickness deviations as they occur during extrusion, allowing for preliminary correction before the entire product batch becomes defective. This enables及时调整 of extrusion parameters to prevent further out-of-specification production.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If NMR sensor with permanent magnet is used for hot extruded product, then continuous measurement is possible, but permanent magnet temperature stability becomes critical

Engineering Contradiction:
Improvelayer thickness measurementVSAvoidpermanent magnet temperature stability
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

The patent addresses the temperature stability issue by selecting permanent magnet materials and designing the NMR sensor system to maintain stable magnetic field parameters at elevated temperatures. The system is configured to compensate for thermal effects on the permanent magnet, ensuring measurement precision is maintained despite the hot environment of the extruded product.

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

Enables precise, rapid measurement of layer thickness and material under hot conditions, reducing waste and ensuring consistent product quality by allowing immediate adjustments to production parameters, thereby maintaining product specifications.

Implementation Method 1

an NMR sensor (17) comprising a temperature resistant permanent magnet and providing a magnetic field B0 with a substantially constant gradient Go in the y-axis

Methodology Applied
Scientific EffectNuclear Magnetic Resonance:

Implementation Method 2

an NMR sensor (17) comprising a temperature resistant permanent magnet and providing a magnetic field B0

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP2376902B1Layer on-line measurement with nmr
Publication Date: 2014.06.25 PIRELLI TYRE SPA
  • EP2376902B1 patent drawingFigure 1~2
  • EP2376902B1 patent drawingFigure 3a~5
  • EP2376902B1 patent drawingFigure 6~7

AI summary

The invention concerns a method and an apparatus for controlling the production of a moving product (13) exciting from a manufacturing apparatus, wherein the moving product (13) is made of an elastomeric material and has at least one layer (23a, 23b, 23c). The method comprises the steps of performing an NMR measurement of the moving product (13), determining of at least one thickness of the at least one layer (23a, 23b, 23c) based on NMR measurement, and adjusting at least one operating parameter of the manufacturing apparatus based on the at least one thickness determined in by the NMR measurement.