Dialysis Solution Controller Reduces Conductivity Fluctuations

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing dialysis solution production methods experience conductivity fluctuations due to discontinuous flow and insufficient mixing, leading to unstable conductivity in the dialyzer, which is undesirable and requires increased equipment and longer cleaning cycles.

Innovation Solution

A device with a controller connected to the conductivity sensor and concentrate pump that adjusts the concentrate supply based on conductivity measurements to maintain a stable conductivity in the dialysis solution, using spectral analysis to identify and eliminate harmonic contributions to the conductivity modulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If concentrates are injected into discontinuous dialysis solution flow, then the dialysis solution can be produced and supplied to the dialyzer, but conductivity fluctuations occur due to insufficient mixing

Engineering Contradiction:
Improvedialysis solution productionVSAvoidconductivity stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The system uses conductivity sensors to continuously monitor the dialysis solution and feeds this information back to the controller, which adjusts the concentrate pump operation accordingly. This closed-loop feedback mechanism ensures that conductivity fluctuations are detected and corrected in real-time, maintaining stable solution composition despite discontinuous flow conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The concentrate pump operates dynamically by adjusting its on/off timing and duration based on real-time conductivity measurements. The controller modulates the pump's operational pattern to synchronize concentrate injection with the discontinuous dialysis solution flow, optimizing mixing conditions and maintaining stable conductivity throughout the treatment.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If mixing chambers are used to achieve constant conductivity, then conductivity stability improves, but the filling volume increases leading to extended cleaning cycles

Engineering Contradiction:
Improveconductivity stabilityVSAvoidhydraulic circuit filling volume
Core Design Contradiction:
Stability of the object's compositionVSVolume of stationary object

Solution Approach 1:

The invention extracts the mixing function from separate physical mixing chambers and integrates it directly into the concentrate delivery system through precise pump control. By controlling when and how much concentrate is added to the discontinuous flow, the system achieves effective mixing without requiring additional volumetric mixing chambers, thus avoiding the associated cleaning time penalties.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system replaces mechanical mixing chambers with a control-based approach using the concentrate pump. Instead of relying on physical mixing structures, the invention uses temporal control of concentrate injection synchronized with the discontinuous flow to achieve the mixing effect, thereby eliminating the need for additional hydraulic volume while maintaining conductivity stability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If continuous concentrate delivery is used, then mixing is simplified, but conductivity fluctuations occur due to lack of synchronization with discontinuous flow

Engineering Contradiction:
Improvemixing simplicityVSAvoidconductivity stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The concentrate pump operates dynamically by adjusting its on/off timing and duration based on real-time conductivity measurements. The controller modulates the pump's operational pattern to synchronize concentrate injection with the discontinuous dialysis solution flow, optimizing mixing conditions and maintaining stable conductivity throughout the treatment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs periodic concentrate injection synchronized with the discontinuous flow pattern. The controller delivers concentrate in periodic pulses that match the flow rhythm, ensuring that concentrate is added at optimal moments when the flow is present, thereby maintaining synchronization and preventing conductivity fluctuations.

Inventive Principle:
Principle #19Periodic 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

Achieves a temporally stable conductivity in the dialysis solution, reducing fluctuations to within ±1-5% of the time average, thereby improving dialysis treatment efficiency and reducing equipment complexity and cleaning times.

Implementation Method 1

a conductivity sensor which is arranged to measure the conductivity of the dialysis solution

Methodology Applied
Scientific EffectConductivity measurement: Conduction (electrical)

Implementation Method 2

Substances are exchanged between the blood and the dialysis solution by diffusion and/or convection

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

Substances are exchanged between the blood and the dialysis solution by diffusion and/or convection

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3906070B1Device and method for producing a dialysis solution
Publication Date: 2024.09.25 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP3906070B1 patent drawingFigure 1~3

AI summary

The present invention relates to a device for producing a dialysis solution, wherein the device has: a dialysate line for conveying a dialysis solution and means that are designed to discontinuously convey a dialysis solution in the dialysate line; a conductivity sensor, which is arranged to measure the conductivity of the dialysis solution; a concentrate line, with a concentrate pump, which upstream of the conductivity sensor leads into the dialysate line at a supply point; and a concentrate container, from which the concentrate pump conveys concentrate into the concentrate line and from the concentrate line into the dialysate line, characterised in that the device has a controller, which is connected to the conductivity sensor and to the concentrate pump and is designed to control the concentrate pump such that the conductivity fluctuations over time in the dialysis solution downstream of the supply point are reduced with respect to a continuous concentrate conveyance.