Medical Fluid Cassette Micro-Leak Detection With Micro-Flow Meter

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Solution Overview

Problem

Existing medical fluid cassettes, particularly those used in dialysis machines, are prone to micro-leaks that go undetected, leading to potential treatment interruptions and damage to the machine.

Innovation Solution

A method and system for detecting micro-leaks in medical fluid cassettes by measuring the rate of net fluid flow between a vacuum reservoir and the cassette membrane using a micro-flow meter, and triggering audible, visual, or tactile indications if the flow exceeds a threshold, prompting corrective actions such as replacing the cassette.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional leak detection methods are used, then device complexity is reduced, but micro-leaks remain undetected leading to treatment interruptions and machine damage

Engineering Contradiction:

Improvedetection accuracyVSAvoiddetection system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical pressure decay detection methods with a micro-flow meter that directly measures fluid flow rates. This substitution enables detection of micro-leaks by quantifying actual fluid movement through the membrane rather than inferring leaks from pressure changes, thereby improving detection accuracy while maintaining reasonable system complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a micro-flow meter as an intermediary measurement device between the vacuum reservoir and the membrane assembly. This intermediary component enables precise measurement of fluid flow rates that would otherwise be undetectable, allowing indirect detection of micro-leaks through flow rate monitoring rather than direct visual inspection

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If no leak detection is performed, then device complexity and operational time are reduced, but undetected micro-leaks cause treatment interruptions and machine damage

Engineering Contradiction:

Improvetreatment continuityVSAvoidtesting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs leak detection before initiating dialysis treatment by applying vacuum pressure and measuring flow rates through the membrane. This preliminary testing action identifies micro-leaks in advance, preventing treatment interruptions later and ensuring machine safety, thereby protecting treatment continuity despite the additional pre-testing time required

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If micro-flow meter measurement is implemented, then micro-leak detection precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improveflow rate measurement precisionVSAvoidmeasurement system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces imprecise pressure decay measurement methods with a micro-flow meter that directly measures fluid flow rates. This substitution provides quantitative data on actual fluid movement through the membrane, enabling precise detection of micro-leaks that conventional methods cannot identify, thereby achieving high measurement precision with a specialized measurement device

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

Accurately detects micro-leaks before treatment, preventing treatment interruptions and potential machine damage by identifying and replacing faulty cassettes, thereby enhancing the reliability and safety of dialysis treatments.

Implementation Method 1

decreasing a pressure between a vacuum reservoir of a medical treatment machine and a membrane of the medical fluid cassette

Methodology Applied

Scientific EffectVacuum pressure: Vacuum

Implementation Method 2

measuring, using a flow meter, a rate of net fluid flow between the vacuum reservoir and the membrane

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS12427234B2Medical fluid cassette leak detection methods and devices

Publication Date: 2025.09.30 FRESENIUS MEDICAL CARE HOLDINGS INC

AI summary

This disclosure relates to medical fluid cassette leak detection methods and devices. In some implementations, a method of detecting micro-leaks in a medical fluid cassette, the method includes decreasing a pressure between a vacuum reservoir of a medical treatment machine and a membrane of the medical fluid cassette when the medical fluid cassette is coupled to the medical treatment machine; measuring, using a flow meter, a rate of net fluid flow between the vacuum reservoir and the membrane of the medical fluid cassette; determining that the rate of net fluid flow between the vacuum reservoir and the membrane of the medical fluid cassette is above a threshold value; and in response to determining that the rate of net fluid flow is above the threshold value, causing the medical treatment machine to take a particular action.