Dialysis Conductivity Sensor With Multi-Electrode Shielding

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Solution Overview

Problem

Current dialysis systems face challenges in accurately measuring conductivity of dialysate and water due to interference from electrical noise and leakage currents, limiting the flexibility and accuracy of home dialysis treatments.

Innovation Solution

A conductivity sensor with a seven-electrode configuration and distinct cell constants for pairs of sense electrodes is used to shield from noise and provide a wider range of accurate conductivity measurements, combining different cell constants to achieve a broader acceptable measurement range with reduced error.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional conductivity sensor is used, then the structure is simple, but the measurement precision deteriorates due to electrical noise and leakage currents

Engineering Contradiction:
Improveconductivity measurement precisionVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor is divided into multiple electrodes (at least four electrodes including first, second, third, and fourth electrodes) with distinct cell constants rather than using a single electrode pair. This segmentation allows different electrode pairs to measure conductivity at different sensitivity levels, enabling the system to select or combine measurements from electrode pairs with appropriate cell constants for the current measurement range, thereby improving precision while managing complexity through modular electrode design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conductivity sensor is designed to perform multiple measurement functions using the same physical structure. By incorporating at least four electrodes that form multiple electrode pairs with different cell constants, the sensor can measure conductivity across a wide range of values (from low to high conductivity) using the same device, eliminating the need for multiple specialized sensors and achieving universal applicability for different dialysate concentration scenarios

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

2Adaptability or versatility

If a single cell constant sensor is used, then the device complexity is low, but the adaptability deteriorates due to limited measurement range

Engineering Contradiction:
Improvemeasurement rangeVSAvoidelectrode configuration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The sensor system dynamically selects or combines measurements from different electrode pairs based on the measured conductivity value. The control system adjusts which electrode pairs (with different cell constants) are used for measurement depending on the conductivity range, allowing the sensor to adapt to varying dialysate concentrations throughout the treatment process. This dynamic adaptation expands the effective measurement range without requiring manual intervention or complex hardware switching

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sensor effectively creates a composite measurement capability by combining data from multiple electrode pairs with different cell constants. Rather than relying on a single electrode configuration, the system integrates measurements from multiple electrode pairs (each acting as a 'material' with different measurement characteristics) to achieve a comprehensive measurement range that covers both low and high conductivity conditions in dialysis applications

Inventive Principle:
Principle #40Composite materials

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 enables precise and reliable conductivity measurements in dialysis systems, enhancing the flexibility and accuracy of home dialysis treatments by minimizing measurement errors and interference, thus improving patient scheduling and treatment outcomes.

Implementation Method 1

a conductivity sensor with a seven-electrode configuration and distinct cell constants for pairs of sense electrodes is used to shield from noise and provide a wider range of accurate conductivity measurements

Methodology Applied
Scientific EffectElectrical Conductivity: Conduction (electrical)

Data Source

PatentEP3193963B1Dialysis machine having a conductivity sensor for determining fluid properties
Publication Date: 2019.07.31 OUTSET MEDICAL
  • EP3193963B1 patent drawingFigure 1
  • EP3193963B1 patent drawingFigure 2~3
  • EP3193963B1 patent drawingFigure 4

AI summary

This disclosure describes systems, devices and methods related to embodiments of a dialysis system, including a home dialysis system, having a conductivity sensor or sensing system that measures conductivity in fluid associated with the dialysis system. For example, the conductivity sensor of the dialysis system can measure the conductivity of dialysate in order to determine its composition and verify proportioning of the dialysate. The conductivity sensor can also measure the purity of water and verify its proportioning in the dialysis system. In addition, the conductivity sensor can be configured to detect conductivity of the fluid within an acceptable range.