Medical Fluid Heating Interface for Sub-10 μA Leakage

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing medical appliances face challenges in achieving low patient leakage currents, particularly for cardiac floating (CF) levels of less than 10 μA, especially when high power is required, as commercially available power supplies typically meet body floating (BF) levels, limiting their use to specific locations and complicating portability.

Innovation Solution

A heating system with a receptacle for medical fluid, an applied part, a heating element, and an interface device that includes conductive and insulating materials to limit inductive and capacitive coupling, ensuring leakage currents remain below 10 μA, even when using class II power supplies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If grounding is used on the secondary side of the power supply or on the applied parts, then leakage currents are reduced, but the appliance requires certification checks by a certified electrician and limits portability

Engineering Contradiction:

Improveleakage current reductionVSAvoidportability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces an intermediary device (isolation transformer or isolation amplifier) between the power supply and the applied parts to achieve galvanic isolation. This mediator blocks the leakage current path to ground while maintaining functional operation, allowing the appliance to be used in locations without certified electrical outlets.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional grounding-based protection mechanism with an electrical isolation mechanism using transformers or optocouplers. This substitution eliminates the need for physical connection to ground while maintaining safety, enabling portability without sacrificing leakage current protection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If class II power supply without grounding protection is used, then portability is improved, but leakage currents increase beyond CF level

Engineering Contradiction:

ImproveportabilityVSAvoidleakage current level

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the electrical system into isolated sections using multiple insulation barriers and galvanic isolation components. By dividing the system into electrically separated segments, the leakage current path is interrupted, enabling class II power supply usage while maintaining CF-level safety.

Inventive Principle:

Principle #1Segmentation

3Temperature

If heating element is added to heat medical fluid, then fluid heating capability is improved, but leakage currents propagate through fluid paths to applied parts

Engineering Contradiction:

Improvefluid heating capabilityVSAvoidleakage current propagation

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent introduces an intermediary heating mechanism such as an ultrasonic heater or a heater separated by an electrically insulating barrier. This intermediary heating method provides thermal energy to the fluid without creating a direct electrical coupling path, preventing leakage current propagation while maintaining heating capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct electrical heating elements with alternative heating mechanisms such as ultrasonic vibration, electromagnetic induction through isolation barriers, or heat exchange via isolated surfaces. This substitution eliminates direct electrical contact with the fluid while maintaining effective heating, preventing leakage current propagation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 system effectively reduces leakage currents to less than 10 μA, allowing medical appliances to be used portably and safely without grounding, meeting cardiac floating standards even with high power requirements.

Implementation Method 1

interface device that includes conductive and insulating materials to limit inductive and capacitive coupling

Methodology Applied

Scientific EffectInductive coupling: Electromagnetic Induction

Implementation Method 2

interface device that includes conductive and insulating materials to limit inductive and capacitive coupling

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 3

heating element, and an interface device disposed between the heating element and the medical fluid

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS12383662B2Heating system with low leakage current

Publication Date: 2025.08.12 NEXTKIDNEY SA

AI summary

A heating system for medical fluid that comprises a receptacle for medical fluid to be heated, a heating element powered by a power supply inducing a leakage current (to ground) ranging between 100 and 10 μA. The heating system further comprises an interface device (for example, an electrical insulation and thermal interface device) disposed between the heating element and the medical fluid contained in the receptacle, allowing the heating system to induce a leakage current in the medical fluid that is less than 10 μA at the applied part.