Fluid Conduit Isolation Using Purified Water to Limit Leakage Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Medical electrical equipment can induce harmful patient leakage current through conductive fluid connections, particularly when connected to a grounded water source or external voltage sources, posing a risk of electric shock.
Innovation Solution
Implement a water purification system that produces purified water with high resistivity to disrupt the conductive path between the patient and ground by controlling the resistivity and physical characteristics of fluid conduits, ensuring the total resistance is sufficient to keep leakage current below safe levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conductive fluid connections are used between patient and medical electrical equipment, then fluid handling function is improved, but patient leakage current risk increases
Solution Approach 1:
The patent introduces an intermediary substance (purified water with controlled resistivity) between the patient and the medical electrical equipment through fluid conduits. This intermediary fluid path, with resistance values carefully controlled to be at least 10 kΩ, acts as a mediator that allows fluid handling while limiting harmful electrical current flow to safe levels below 10 μA
Solution Approach 2:
The patent changes the electrical resistance parameter of the fluid path by controlling the resistivity of the fluid (purified water) and the physical dimensions (length and inner diameter) of the fluid conduits. By adjusting these parameters, the total resistance is maintained at至少 10 kΩ, which simultaneously enables effective fluid handling and ensures patient safety by limiting leakage current
2Object-affected harmful factors
If fluid conduit length and inner diameter are increased to increase resistance, then leakage current is reduced, but fluid flow capability deteriorates
Solution Approach 1:
The patent optimizes the parameters of the fluid conduit (length and inner diameter) to achieve the minimum required resistance (at least 10 kΩ) while maintaining adequate fluid flow capability. This involves carefully selecting conduit dimensions that balance electrical isolation requirements with fluid handling efficiency, rather than maximizing either parameter extremes
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
Effectively prevents unsafe patient leakage current by maintaining resistance values in the fluid path, adhering to international safety standards and ensuring patient safety during medical treatments.
Implementation Method 1
Implement a water purification system that produces purified water with high resistivity to disrupt the conductive path between the patient and ground by controlling the resistivity and physical characteristics of fluid conduits
Data Source
AI summary
A method of reducing leakage current from a patient to a ground potential through an applied part of a medical device includes defining a maximum permissible leakage current Amax from the patient to the ground potential when the patient is energized to an electric potential V and supplying the medical device with water having a resistivity value ρ through a fluid line having a length L and an inner diameter ID. The value of L and ID is selected to cause the fluid conduit filled with water of resistivity ρ to have a resistance of R high enough to maintain the leakage current from the patient to the ground potential below Amax.