Dialysate Conductivity Sensor Diagnosis Using A-Liquid
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Solution Overview
Problem
Conductivity sensors in dialysis fluid preparation machines face challenges in accurately measuring the conductivity of dialysate solutions, especially when bicarbonate concentrates are provided as dry concentrates, as solubility is temperature-dependent, requiring additional sensors and calculations to predict conductivity.
Innovation Solution
A diagnostic method and apparatus that assess the accuracy of concentration measuring means by measuring the electrical conductivity of the A liquid before preparing the dialysate, using a predetermined value for undiluted or diluted A liquid, and displaying error messages if deviations occur, to diagnose potential malfunctions and ensure accurate concentration measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conductivity sensors are used to measure dialysate concentration, then the measurement is affected by temperature and liquid volume variations, but adding additional sensors and calculations increases device complexity
Solution Approach 1:
The patent extracts the diagnostic function from the normal measurement process by diverting A-liquid through a separate diagnostic channel to the conductivity sensor. This allows independent testing of the sensor without requiring temperature compensation or additional sensors, as the A-liquid concentration is known and temperature-independent.
Solution Approach 2:
The patent introduces A-liquid as an intermediary substance for sensor diagnosis. By using A-liquid with known, stable concentration properties instead of bicarbonate solution, the system achieves temperature-independent measurement validation without requiring temperature sensors or complex calculations.
2Ease of manufacture
If bicarbonate concentrate is used as dry concentrate, then solubility becomes temperature-dependent requiring temperature sensors and calculations, but using ready-to-use solutions increases storage requirements
Solution Approach 1:
The patent extracts the temperature dependency problem by removing bicarbonate solution from the diagnostic process entirely. Instead, it uses A-liquid which has temperature-independent solubility characteristics, eliminating the need for temperature sensors and solubility calculations.
Solution Approach 2:
The patent treats the diagnostic measurement as a temporary, disposable function using A-liquid that is diverted only when needed for sensor diagnosis. This avoids the permanent complexity of temperature compensation systems while maintaining measurement accuracy when required.
3Measurement precision
If A-liquid and B-liquid are mixed in predetermined proportions to produce dialysis fluid, then the concentration measurement becomes dependent on mixing accuracy, but increasing measurement points increases device complexity
Solution Approach 1:
The patent performs preliminary diagnosis of the conductivity sensor using A-liquid before actual dialysis fluid measurement. This preliminary action validates the sensor's functionality and establishes a baseline, ensuring that subsequent measurements of mixed dialysis fluid are reliable without requiring additional measurement points.
Solution Approach 2:
The patent maintains continuous monitoring capability by using the same conductivity sensor for both diagnostic measurements with A-liquid and actual dialysis fluid measurements. This continuous use of the single sensor maximizes its utility without requiring additional sensors or measurement points.
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 the independence of the measurement from temperature and liquid volume variations, reducing errors and ensuring precise conductivity measurement, thereby improving the reliability of the dialysis fluid preparation process.
Implementation Method 1
measuring the electrical conductivity of the A-liquid with the concentration meter
Data Source
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AI summary
The invention relates to a diagnosis method for a conductivity sensor for a dialysis fluid preparation device and a personal dialysis device, which mix water, a fluid A or a fluid B in predefined proportions in order to prepare a dialysis fluid, wherein the concentration of the prepared dialysis fluid is measured using concentration measuring means. The diagnosis method and the corresponding device are based on the measuring of fluid A without fluid B being present in the solution.