Moisture Detection Pad With External Terminating Resistor

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Solution Overview

Problem

Existing moisture detection devices for monitoring vascular access in extracorporeal blood treatment face challenges with manufacturing complexity, mechanical stress resistance, reproducibility, and biocompatibility, particularly due to issues with printed terminating resistors that are prone to deviation and degradation from patient movement and sweat exposure.

Innovation Solution

A moisture detection device featuring separate, reusable terminating resistors and printed conductor tracks on a flexible carrier material, allowing for improved mechanical stability, reproducibility, and biocompatibility, with the terminating resistor being external to the pad to avoid mechanical stress and biocompatibility concerns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a printed terminating resistor is used on the carrier material, then manufacturing effort is reduced, but production tolerances and flexural fatigue strength deteriorate

Engineering Contradiction:
Improvemanufacturing effortVSAvoidproduction tolerances
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The terminating resistor is extracted from the disposable pad and placed in the reusable monitoring device. This allows the pad to be manufactured simply with printed conductor tracks while the terminating resistor, requiring precise tolerances, is manufactured separately with appropriate precision in the durable monitoring device.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system is segmented into two parts: a disposable pad with printed conductor tracks and a reusable monitoring device containing the terminating resistor. This segmentation allows each component to be optimized independently - the pad for low-cost manufacturing and the monitoring device for precision and durability.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If a printed terminating resistor is used on the carrier material, then manufacturing effort is reduced, but flexural fatigue strength deteriorates

Engineering Contradiction:
Improvemanufacturing effortVSAvoidflexural fatigue strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The terminating resistor is extracted from the disposable pad and placed in the reusable monitoring device. This allows the pad to be manufactured simply with printed conductor tracks while the terminating resistor, requiring precise tolerances, is manufactured separately with appropriate precision in the durable monitoring device.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pad with printed conductor tracks is designed as a disposable, low-cost component that can be manufactured with simpler printing processes. The terminating resistor is placed in the reusable monitoring device that withstands mechanical stress and can be maintained over time.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If the terminating resistor is embedded in the flexible material, then mechanical stability deteriorates due to constant bending, but integration is improved

Engineering Contradiction:
ImproveintegrationVSAvoidmechanical stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The terminating resistor is extracted from the disposable pad and placed in the reusable monitoring device. This allows the pad to be manufactured simply with printed conductor tracks while the terminating resistor, requiring precise tolerances, is manufactured separately with appropriate precision in the durable monitoring device.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system separates static components (terminating resistor in the monitoring device) from dynamic components (flexible pad that bends during patient movement). This allows the static resistor to remain stable while the dynamic pad performs its moisture detection function.

Inventive Principle:
Principle #15Dynamics

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 solution provides a reliable, cost-effective, and biocompatible moisture detection system that withstands mechanical stress and ensures reproducible results, enabling effective monitoring of vascular access and potential applications beyond blood treatment devices.

Implementation Method 1

The pad consists of an absorbent material in which a moisture sensor is embedded. The moisture sensor of WO 2006/008866 A1 has two conductor tracks that are applied to a carrier material.

Methodology Applied
Scientific EffectElectrical conductivity: Conduction (electrical)

Data Source

PatentEP2585131B1Device for detecting moisture for use with a device for monitoring access to a patient
Publication Date: 2015.09.16 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP2585131B1 patent drawingFigure 1
  • EP2585131B1 patent drawingFigure 2~3
  • EP2585131B1 patent drawingFigure 4

AI summary

The invention relates to a device for detecting moisture which is designed as a cover 30 to be placed on the skin of a patient, and to a device B for monitoring access to a vessel. The cover 30 comprises a flexible base material 31 to which an electrically conductive structure 32 composed of conductive tracks 33, 34 is applied to serve as a moisture sensor. The device 40 is characterised in that the electrically conductive structure 32 comprises two conductive tracks 33, 34, wherein one end of the first conductive track and one end of the second conductive track comprise a first pair of connection contacts 35A, 35G and the other end of the first conductive track and the other end of the second conductive track comprise a second pair 35C, 35E of connection contacts. The first pair of connection contacts is used to connect a device B for monitoring access to a vessel, whereas the second pair of connection contacts is used to connect a terminating resistor R. The device can be produced cost-effectively in large quantities. Using the separate terminating resistor there is no danger for the terminating resistor to be destroyed as a result of movements by the patient or for the resistance thereof to change.