Fluid Concentration Measurement with Backflow Detection

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Solution Overview

Problem

In artificial dialysis apparatuses, backflow of blood can occur due to pump characteristics, leading to inaccurate measurement of blood concentration and flow volume when using light-based measurement techniques.

Innovation Solution

A fluid measuring apparatus that detects backflow by analyzing changes in reflected light intensity and corrects the measurement signals to accurately estimate fluid concentration, using a combination of light receiving elements, backflow detectors, and signal processing to differentiate between forward and backward fluid flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If light-based measurement is used to measure blood concentration and flow volume, then measurement capability is provided, but measurement accuracy deteriorates when backflow occurs

Engineering Contradiction:
Improveblood concentration measurement accuracyVSAvoidmeasurement reliability under backflow conditions
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the light measurement into two independent components: transmitted light measurement for concentration calculation and reflected light measurement for backflow detection. By separating these functions, the system can identify backflow conditions and exclude affected transmitted light measurements from concentration calculations, thereby maintaining measurement accuracy even when backflow occurs

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces reflected light as an intermediary indicator to detect backflow conditions. Instead of directly measuring backflow, the system uses reflected light intensity changes as a proxy signal to infer backflow occurrence, which then triggers exclusion of corresponding transmitted light measurements from concentration calculations

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If simple transmitted light measurement is used, then device complexity is reduced, but measurement accuracy deteriorates due to backflow interference

Engineering Contradiction:
Improvemeasurement system complexityVSAvoidconcentration measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent makes the reflected light detection system serve multiple functions: it detects backflow conditions and simultaneously provides timing information for excluding corrupted transmitted light measurements. This multi-functionality allows the system to maintain simple transmitted light measurement while adding minimal complexity through the reflected light channel

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system performs preliminary detection of backflow conditions using reflected light measurements before final concentration calculation. By detecting backflow in advance through reflected light changes, the system can pre-identify which transmitted light measurements should be excluded, preventing accuracy degradation before it occurs

Inventive Principle:
Principle #10Preliminary action

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 apparatus effectively suppresses the influence of backflow on concentration measurement, ensuring accurate estimation of fluid concentration even during temporary backflow events, thereby improving the reliability of fluid measurement in artificial dialysis applications.

Implementation Method 1

A fluid measuring apparatus is provided with a light receiving device configured to receive scattered light

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

there is known an apparatus configured to irradiate a fluid with light and to receive scattered light

Methodology Applied
Scientific EffectLight transmission: Light

Data Source

PatentEP3534150B1Fluid measuring device
Publication Date: 2022.07.06 AIR WATER BIODESIGN INC
  • EP3534150B1 patent drawingFigure 1
  • EP3534150B1 patent drawingFigure 2
  • EP3534150B1 patent drawingFigure 3

AI summary

A fluid measuring apparatus is provided with: an irradiating device configured to irradiate a fluid with light; a light receiving device configured to receive light scattered by the fluid; a detecting device configured to detect a backflow of the fluid on the basis of a received light signal of the light receiving device; and a calculating device configured to calculate estimated concentration information indicating a concentration of the fluid, on the basis of a detection result of the detecting device and the received light signal of the light receiving device. By this, even if the backflow temporarily occurs in the fluid, the fluid concentration can be accurately measured.