Electromagnetic Flow Meter Liner Abrasion Detection

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Solution Overview

Problem

Electromagnetic flow meters with thermally insulating liners face challenges in detecting liner abrasion, which affects measurement accuracy and insulation, as existing methods are not effective due to the low thermal conductivity of these materials.

Innovation Solution

A measurement device with temperature sensors measuring temperature gradients across the measurement tube wall, comparing the measured gradient to a reference, and calculating the liner thickness based on thermal conductivity and temperature differences to detect abrasion and estimate remaining liner thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thermally insulating liner is used in an electromagnetic flow meter, then electrical insulation between measuring electrodes and measurement tube is improved, but detection of liner abrasion becomes difficult due to low thermal conductivity

Engineering Contradiction:
Improveelectrical insulationVSAvoidliner abrasion detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces temperature sensors as intermediary elements to detect thermal changes caused by liner abrasion. The sensors measure temperature differences between the fluid and ambient environment, using the liner itself as a thermal mediator whose changing thickness affects the temperature gradient, thereby enabling indirect detection of abrasion despite the liner's insulating properties

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical or visual inspection methods with a thermal field-based detection system. By substituting mechanical measurement approaches with thermal conductivity-based sensing, the system can detect liner condition through temperature gradients without requiring direct contact with or visualization of the liner interior

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

2Measurement precision

If temperature sensors are mounted on the outside of a measurement tube with metal wall, then liner abrasion can be detected effectively, but the thermal conductivity of the tube wall affects measurement accuracy

Engineering Contradiction:
Improveabrasion detection accuracyVSAvoidtemperature measurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the measurement parameter from direct temperature sensing to temperature gradient sensing. By measuring the difference in temperature between two points (inside and outside the tube wall) rather than absolute temperature, the system compensates for the thermal conductivity variations of the tube wall material, maintaining measurement reliability across different materials

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses the measured temperature gradient as feedback to calculate and monitor liner thickness over time. By continuously comparing temperature differences and analyzing the thermal resistance changes, the system provides ongoing feedback about liner condition, enabling trend analysis and early warning of abrasion before it reaches critical levels

Inventive Principle:
Principle #23Feedback

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 early detection of liner abrasion, allowing for timely countermeasures to prevent measurement errors and schedule replacements efficiently, ensuring accurate and reliable operation.

Implementation Method 1

measuring means (15) for measuring a temperature gradient across a measurement tube wall (1; 3; 5) of the measurement tube, when the measurement tube wall is exposed to a temperature difference between an ambient temperature and a fluid temperature of the fluid

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3184973B1Device for measuring a property of a flowing fluid
Publication Date: 2019.05.01 ENDRESS HAUSER FLOWTEC AG
  • EP3184973B1 patent drawingFigure 1~2

AI summary

A measurement device, in particular a flow meter, in particular an electromagnetic flow meter, for measuring a property, in particular a flow, of a flowing fluid, comprising a measurement tube (1) comprising an outer tube (3) and a liner (5) lining an inside of said outer tube (3), and measurement means for measuring a property of a fluid flowing through the lined measurement tube (1) during measurement operation, capable of detecting abrasion of said liner (5) is described, characterized in that, said liner (5) consists of a thermally insulating material, in particular a rubber or a plastic material, means are foreseen for measuring a temperature gradient (ΔT) across a measurement tube wall of said measurement tube (1), when said measurement tube wall is exposed to a temperature difference (ΔTL/A) between an ambient temperature (TA) and a fluid temperature (TL/A) of said fluid, and detecting means (17) for detecting abrasion of said liner (5) are foreseen, detecting abrasion in case a deviation between said measured temperature gradient (ΔT) and a predetermined reference temperature gradient (ΔTref(ΔTL/A)) representing a temperature gradient across a measurement tube wall exposed to the same or at least a similar temperature difference (ΔTL/A) of an identical measurement tube (1) comprising an unimpaired liner (5) exceeds a predetermined limit.