Protective Conductor Circuit for Redundant Fluid Line Grounding

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Solution Overview

Problem

Existing medical devices, particularly dialysis machines, lack an effective and efficient method to ensure redundant electrical safety connections for fluid-carrying lines, complicating compliance with electrical safety regulations and making safety inspections cumbersome.

Innovation Solution

A circuit arrangement with multiple protective devices for each fluid-carrying line, ensuring redundant electrical connections by cross-connecting protective devices between lines, allowing for simplified safety verification without additional structural modifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple protective devices are assigned to each liquid-carrying line, then electrical safety and redundancy are improved, but device complexity increases

Engineering Contradiction:
Improveelectrical safetyVSAvoidprotective device configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The protective conductor connection is segmented into multiple independent protective devices (first protective device on first liquid-carrying line, second protective device on second liquid-carrying line). This segmentation provides redundancy - if one protective connection fails, the other remains functional, thereby improving electrical safety without requiring complete reconfiguration of the entire protective system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The circuit arrangement incorporates redundant protective devices in advance, creating a backup protective connection before any failure occurs. This prior cushioning ensures that if one protective connection becomes defective, the system already has an alternative protective path ready, maintaining patient safety without requiring immediate intervention or system shutdown.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If protective devices are cross-connected between liquid-carrying lines, then redundancy is improved, but circuit complexity increases

Engineering Contradiction:
Improveprotective conductor connectionVSAvoidcircuit arrangement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The circuit arrangement merges the protective conductor connections from multiple liquid-carrying lines into a unified protective network. The first protective device on the first liquid-carrying line and the second protective device on the second liquid-carrying line are electrically connected through the protective conductor, creating a combined protective system that provides redundancy across different fluid lines while maintaining a relatively simple overall circuit structure.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If redundant protective connections are implemented, then patient safety is improved, but manufacturing effort increases

Engineering Contradiction:
Improvepatient safetyVSAvoidassembly effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The protective devices are designed with multi-functionality, serving both as electrical contacts for the liquid-carrying lines and as integrated protective conductor connections. This universal design allows the same components to fulfill multiple functions - fluid transport interface and electrical protection - thereby improving patient safety through redundancy without requiring separate additional protective components that would increase manufacturing complexity.

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

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

Enhances electrical safety by providing redundant grounding, simplifies safety inspections, and maintains patient safety even if one connection fails, all while minimizing technical effort and avoiding the need for additional structural changes.

Implementation Method 1

protective devices for electrical contacting, which are designed such that an electrical connection to a liquid contained in the line can be established with each protective device

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3697465B1Circuit for connecting a protective conductor to at least two liquid-conveying lines and method for checking a protective conductor connection
Publication Date: 2026.03.18 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP3697465B1 patent drawingFigure 1
  • EP3697465B1 patent drawingFigure 2~3
  • EP3697465B1 patent drawingFigure 4~5

AI summary

The invention relates to a circuit arrangement for connecting a protective conductor to at least two liquid-conveying lines (11, 12), particularly to at least two liquid-conveying lines leading from inside a housing (1) of a medical appliance, particularly the housing of a blood treatment appliance, to the outside. The circuit arrangement comprises a plurality of protective devices (16A, 16B; 17A, 17B) for electrical contacting, which are designed such that each one can be used to create an electrical connection to a liquid circulating in the line. At least two protective devices (16A, 16B; 17A, 17B) for electrical contacting are associated with each liquid-conveying line (11, 12) in the circuit arrangement. Two protective measures are therefore taken for each liquid-conveying line. Furthermore, the protective devices (16A, 16B; 17A, 17B) of a liquid-conveying line (11; 12) are respectively electrically connected to another protective device (16A,16B;17A, 17B) of another liquid-conveying line (11; 12). The protective conductor concept according to the invention improves the safety of the patients and allows easy checking of the protective conductor connections.