Dialysis Machine Heat Exchanger Isolation

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Solution Overview

Problem

Existing dialysis machines risk contaminating the central RO water supply with used dialysis fluid due to potential leaks in the heat exchanger, necessitating costly monitoring systems to prevent contamination.

Innovation Solution

The dialysis machine incorporates a water inlet system with a physical separation mechanism, such as a free-fall path, to isolate the external water supply from the downstream sections, and positions the heat exchanger downstream of the water inlet tank, ensuring that even if a leak occurs, the RO water supply remains uncontaminated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a heat exchanger is used to transfer heat from used dialysis fluid to RO water, then energy efficiency is improved, but the risk of contaminating the RO water supply increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcontamination risk
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The water inlet system is divided into separate sections: an external water supply section and a downstream section containing the heat exchanger. This segmentation creates physical isolation between the RO water supply and the heat exchanger, allowing heat transfer functionality while preventing contamination pathways.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A free-fall section acts as an intermediary element between the external water supply and the heat exchanger. The free-falling water creates a physical barrier that prevents backflow and contamination while maintaining the heat transfer function of the heat exchanger.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a sensor and monitoring system are installed to detect leaks in the heat exchanger, then contamination detection capability is improved, but system complexity and cost increase

Engineering Contradiction:
Improvecontamination detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The design converts the potential harm of a heat exchanger leak into a beneficial outcome by using the free-fall section's physical barrier properties. Even if contamination occurs in the heat exchanger, the free-fall section prevents it from reaching the external water supply, eliminating the need for complex detection systems.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system uses its own structural design (free-fall section) to provide contamination protection without requiring external monitoring devices. The physical barrier itself serves the protective function, making additional sensors unnecessary.

Inventive Principle:
Principle #25Self-service

3Use of energy by moving object

If the heat exchanger is positioned upstream of the water inlet tank, then heat transfer efficiency is improved, but the risk of contaminating the external water supply increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidwater supply contamination
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

Instead of placing the heat exchanger upstream where it would have direct access to the water supply, the design inverts the arrangement by positioning it downstream. This inversion maintains heat transfer functionality while reversing the contamination risk direction, protecting the external water supply.

Inventive Principle:
Principle #13The other way round (Inversion)

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 design effectively prevents contamination of the RO water supply, eliminating the need for costly leak detection sensors and ensuring the integrity of the dialysis center's water supply, while also enhancing the heat exchanger's effectiveness by maintaining the separation of used dialysis fluid and RO water.

Implementation Method 1

a heat exchanger (40) which is connected on the one hand to the line (30) for used dialysis fluid and on the other hand to the water inlet system, so that heat is transferred from the used dialysis fluid to the water in the water inlet system

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a free-fall section for incoming fluid from the water supply, wherein the water coming from the water supply falls freely from a higher starting level into a lower basin

Methodology Applied
Scientific EffectFree fall: Free Fall

Implementation Method 3

The basin can be connected to the downstream sections of the water inlet system, for example by means of a siphon pipe

Methodology Applied
Scientific EffectSiphon effect: Syphon

Data Source

PatentEP3355951B1Dialysis machine
Publication Date: 2021.04.21 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP3355951B1 patent drawingFigure 1

AI summary

A dialysis machine having: a dialyzer (D); a water input system, which is connected to the dialyzer and an external water supply system, for supplying the dialyzer (D) with fresh dialysis fluid; and a line (32), which is connected to the dialyzer (D), for used dialysis fluid, wherein the water input system has a container (20) for water or another fluid, in particular for RO water, and wherein the dialysis machine also has a heat exchanger (40) which is connected both to the line (32) for used dialysis fluid and to the water input system so that heat from the used dialysis fluid is transferred to the fluid situated in the water input system, wherein the container (20) has a device for physically separating the external water supply system and the downstream portions of the water input system, preferably a free-fall section for incoming fluid from the water supply system, and wherein the heat exchanger is situated downstream of the container.