Capacitive Measurement Circuit for Moving Textile Materials

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Solution Overview

Problem

Existing devices for capacitive measurement of textile materials, such as yarn or sliver, face limitations in sensitivity, load capacity, and operational efficiency, particularly in measuring thin items and managing dust accumulation, while also requiring high operating voltages and costly components.

Innovation Solution

The device focuses on selectively activating only the measuring capacitor where the test material is present, reducing overall circuit capacitance and increasing sensitivity by a factor equal to the number of capacitors, while using cheaper components and minimizing dust impact through a capacitive measuring circuit with electrically actuable selection means like multiplexers or switches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple measuring capacitors are connected in parallel to measure different test materials simultaneously, then the device can handle multiple through openings and different test material sizes, but the overall circuit capacitance increases which reduces measurement sensitivity

Engineering Contradiction:
Improveability to measure different test material sizesVSAvoidmeasurement sensitivity
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements dynamic switching of measuring capacitors using electrically actuable selection means (multiplexer or switches). Only one measuring capacitor is actively connected to the evaluation electronics at any given time, while others remain disconnected. This dynamic configuration allows the system to maintain high measurement sensitivity by excluding unused capacitors from the active circuit, while still providing adaptability to measure different test material sizes by selecting the appropriate capacitor through control signals.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If all measuring capacitors remain connected in the circuit, then the device structure is simpler, but the load capacity of the amplifier decreases and power consumption increases

Engineering Contradiction:
Improvecircuit structure simplicityVSAvoidpower consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent extracts unused measuring capacitors from the active measurement circuit by disconnecting them through electrically actuable switches or multiplexer selection. This extraction removes the capacitive load of inactive capacitors from the amplifier, reducing power consumption and preventing signal degradation. The switches are controlled by control signals that activate only the specific measuring capacitor corresponding to the current measurement position, thereby eliminating unnecessary energy consumption while maintaining circuit functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If multiple measuring capacitors are used to cover different measurement ranges, then the device can measure various test material dimensions, but dust accumulation in through openings increases signal drift

Engineering Contradiction:
Improvemeasurement range coverageVSAvoidsignal stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent removes inactive measuring capacitors from the active measurement circuit using electrically actuable selection means. When a particular measuring capacitor is not in use, it is electrically disconnected from the evaluation electronics, preventing dust accumulation in its through opening from affecting the measurement signal. This selective extraction ensures that only the currently active measuring capacitor influences the measurement, thereby eliminating signal drift caused by dust in unused through openings while maintaining the ability to measure various test material dimensions.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enhances measurement sensitivity, reduces power consumption, allows for the measurement of very thin items, and decreases dust-related signal drift, achieving improved signal-to-noise ratios and reduced manufacturing costs.

Implementation Method 1

each of the at least two measuring capacitors being assigned to one of the at least two through openings in such a way that its capacity can be influenced by a test material located in the relevant through opening

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

generator means which are designed to apply at least one alternating electrical signal to the at least two measuring capacitors

Methodology Applied
Scientific EffectAlternating electrical signal:

Data Source

PatentEP2684035B1Device and method for capacitive analysis of a moving test material
Publication Date: 2018.09.12 USTER TECHNOLOGIES AG
  • EP2684035B1 patent drawingFigure 1
  • EP2684035B1 patent drawingFigure 2~3
  • EP2684035B1 patent drawingFigure 4

AI summary

The invention relates to a capacitive measuring circuit (1) for a moving elongate test material (9), comprising at least two measuring capacitors (2.1-2.4), each of which is designed to receive the test material (9). The measuring circuit further comprises electrically operable selection means (7) by means of which one of the measuring capacitors (2.2) can be selected such that only the selected measuring capacitor (2.2), and not the other measuring capacitors (2.1, 2.3, 2.4), contributes to the measurement. The total capacitance of the measuring circuit (1) is thereby reduced and the sensitivity thereof is increased.