Fiber Sheet Sensor Yarn for Dialysis Blood Detection

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Solution Overview

Problem

The existing blood detection devices for artificial dialysis have complex structures that make them costly and non-disposable, and there is a need for a system that can accurately distinguish between blood and other liquids like sweat to prevent misdetected needle removal during artificial dialysis.

Innovation Solution

A fiber sheet with a sensor yarn structure, comprising a first conductive yarn, a first insulating section, and a second conductive yarn wound spirally on the outer circumference of the insulating section, which is designed to accurately determine the presence of specific liquids by measuring impedance and phase differences using alternating current signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complicated structure is used for the moisture sensor to reliably detect blood, then detection reliability is improved, but manufacturing cost increases and the sensor cannot be discarded

Engineering Contradiction:
Improvedetection reliabilityVSAvoidsensor structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor is divided into three functional layers: a water-permeable sheet for liquid contact, a filter sheet for separating blood from sweat based on pore size, and an electrode sheet with patterned electrodes for impedance measurement. This segmentation allows each layer to perform its specific function efficiently, achieving reliable blood detection while using simple, disposable materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filter sheet has different pore sizes in different regions: smaller pores in the blood detection region to prevent blood cells from passing through, and larger pores in the sweat region to allow sweat permeation. This local differentiation enables the sensor to distinguish between blood and sweat based on their different permeation characteristics through specific areas.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If a complicated structure with multiple layers is used for the moisture sensor, then detection precision is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improveliquid detection precisionVSAvoidsensor manufacturing ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The sensor is divided into three functional layers: a water-permeable sheet for liquid contact, a filter sheet for separating blood from sweat based on pore size, and an electrode sheet with patterned electrodes for impedance measurement. This segmentation allows each layer to perform its specific function efficiently, achieving reliable blood detection while using simple, disposable materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filter sheet has different pore sizes in different regions: smaller pores in the blood detection region to prevent blood cells from passing through, and larger pores in the sweat region to allow sweat permeation. This local differentiation enables the sensor to distinguish between blood and sweat based on their different permeation characteristics through specific areas.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If the sensor is designed to be disposable for infection prevention, then safety is improved, but detection reliability may deteriorate due to simpler structure

Engineering Contradiction:
Improveblood infection riskVSAvoiddetection reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The sensor is divided into three functional layers: a water-permeable sheet for liquid contact, a filter sheet for separating blood from sweat based on pore size, and an electrode sheet with patterned electrodes for impedance measurement. This segmentation allows each layer to perform its specific function efficiently, achieving reliable blood detection while using simple, disposable materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filter sheet has different pore sizes in different regions: smaller pores in the blood detection region to prevent blood cells from passing through, and larger pores in the sweat region to allow sweat permeation. This local differentiation enables the sensor to distinguish between blood and sweat based on their different permeation characteristics through specific areas.

Inventive Principle:
Principle #3Local quality

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 system effectively differentiates between blood and other liquids, reducing the likelihood of false detection signals and allowing the disposable use of the fiber sheet, thereby enhancing safety and reducing manufacturing costs.

Implementation Method 1

a first insulating section covering the first conductive yarn and formed of an electrically insulating material having absorbency

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

accurately determine whether a liquid dripping on a fiber sheet is a specific liquid (for example, blood), and it is possible to reduce the likelihood of incorrectly outputting a detection signal

Methodology Applied
Scientific EffectElectrical conductivity: Conduction (electrical)

Data Source

PatentEP3318664B1Fiber sheet
Publication Date: 2024.06.12 THE KITASATO INSTITUTE
  • EP3318664B1 patent drawingFigure 1
  • EP3318664B1 patent drawingFigure 2
  • EP3318664B1 patent drawingFigure 3~4

AI summary

A yarn has a first conductive yarn (231) having conductivity, a first insulating section (232) covering the first conductive yarn (231) and formed of an insulating material having absorbency, and a second conductive yarn (233) having conductivity and disposed on an outer circumferential side of the first insulating section (232).