In-Line Dialysis Fluid Mixing for Accurate SSR Component Dosing
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Solution Overview
Problem
Existing dialysis fluid mixing systems face challenges in accurately dosing components with small signal responses, leading to concentration fluctuations due to evaporation and manufacturing deviations, which are difficult to measure with conventional conductivity sensors.
Innovation Solution
An in-line mixing method and system that temporarily overdoses the small-signal-response (SSR) component to increase its concentration, allowing for accurate measurement and control using concentration feedback, thereby minimizing the impact of measurement noise and flow variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional conductivity sensors are used to measure SSR components at intended dosing rates, then the system structure remains simple, but measurement precision deteriorates due to small signal responses being lost in noise
Solution Approach 1:
The system performs preliminary action by temporarily increasing the dosing rate of the SSR component to an initial dosing rate before establishing the final dosing rate. This preliminary overdosing ensures that the signal response is sufficiently large to be accurately measured by the conductivity sensor, overcoming the problem of small signals being lost in noise. The relationship between the initial and final dosing rates is determined through concentration feedback, allowing the system to achieve both simple device structure and high measurement precision.
2Measurement precision
If the dosing rate of SSR component is increased to improve signal response, then measurement precision improves, but manufacturing precision deteriorates due to concentration fluctuations from evaporation and manufacturing deviations
Solution Approach 1:
The system employs concentration feedback to continuously monitor the actual concentration of the SSR component in the dialysis fluid and adjusts the dosing rate accordingly. The control unit receives concentration values from the conductivity sensor and modifies the dosing rate to maintain the desired final concentration, compensating for evaporation and manufacturing deviations. This feedback mechanism allows the system to achieve both improved signal response through temporary overdosing and maintained manufacturing precision through continuous correction.
3Measurement precision
If temporary overdosing is implemented to enable accurate measurement, then measurement precision improves, but the process duration increases due to additional dosing and adjustment phases
Solution Approach 1:
The system performs preliminary action by temporarily increasing the dosing rate of the SSR component to an initial dosing rate before establishing the final dosing rate. This preliminary overdosing ensures that the signal response is sufficiently large to be accurately measured by the conductivity sensor, overcoming the problem of small signals being lost in noise. The relationship between the initial and final dosing rates is determined through concentration feedback, allowing the system to achieve both simple device structure and high measurement precision.
4Manufacturing precision
If concentration feedback control is implemented, then manufacturing precision improves, but device complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The system employs concentration feedback to continuously monitor the actual concentration of the SSR component in the dialysis fluid and adjusts the dosing rate accordingly. The control unit receives concentration values from the conductivity sensor and modifies the dosing rate to maintain the desired final concentration, compensating for evaporation and manufacturing deviations. This feedback mechanism allows the system to achieve both improved signal response through temporary overdosing and maintained manufacturing precision through continuous correction.
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 method and system enable precise dosing of SSR components, ensuring accurate final concentration of dialysis fluids by establishing a relationship between initial and final dosing rates, thus enhancing mixing accuracy and reducing errors.
Implementation Method 1
monitoring, with a concentration sensor, a concentration of the fluid
Implementation Method 2
A blood filtration unit, commonly known as a dialyzer, is arranged in the EC blood circuit to interface the blood with a dialysis fluid over a semi-permeable membrane
Implementation Method 3
HF is accomplished by adding another dialysis fluid, referred to as infusion fluid, substitution fluid or replacement fluid, to the extracorporeal blood circuit during dialysis therapy
Implementation Method 4
One modality of EC blood therapy is hemodialysis (HD) which in general uses diffusion to remove waste products from the blood. A diffusive gradient occurs across the semi-permeable membrane and the dialysis fluid
Implementation Method 5
Waste, toxins and excess water pass from the patient's bloodstream, through the capillaries in the peritoneal membrane, and into the dialysis fluid by diffusion and osmosis
Implementation Method 6
An osmotic agent in the dialysis fluid provides the osmotic gradient
Implementation Method 7
HF is accomplished by adding another dialysis fluid, referred to as infusion fluid, substitution fluid or replacement fluid, to the extracorporeal blood circuit during dialysis therapy
Data Source
AI summary
A method and a mixing system (20) for in-line mixing components of a medical fluid in a mixing system (20), the medical fluid having a final predetermined composition of pure water, a small-signal-response, SSR-, component and optionally at least one electrolyte component. The method comprises: providing (S1) a flow of fluid comprising pure water, or a mixture of pure water and an electrolyte component, in a main fluid line (21); monitoring (S2), with a concentration sensor (26, 60), a concentration of the fluid; providing (S3), with an SSR dosing mechanism (25a), the SSR-component into the flow of fluid upstream the concentration sensor (26, (60); and controlling (S4), with the SSR dosing mechanism (25a), the dosing rate of the SSR-component to an initial dosing rate at which the concentration monitored with the concentration sensor (26, 60) indicates an initial concentration (cSSR_init) of the SSR-component in the fluid that is greater than an intended final predetermined concentration (cSSR_final) of the SSR-component in the medical fluid, in order to determine a relationship between the dosing rate of the SSR-component and the resulting concentration of the SSR-component in the fluid. The method further comprises downscaling (S5), with the SSR dosing mechanism (25a), the dosing rate of the SSR-component to a final dosing rate (QSSR_final) at which the final predetermined concentration (cSSR_final) of the SSR-component in the fluid is achieved, based on the determined relationship.