Respiratory Humidifier Reverse-Flow Detection for Connection Errors

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Solution Overview

Problem

Current respiratory humidification systems lack direct detection mechanisms for reverse flow conditions and incorrect connections between components, leading to suboptimal humidity and temperature delivery to patients, potential device damage, and adverse patient reactions.

Innovation Solution

Implementing sensors and a hardware/software controller to compare temperature and flow parameters at different points in the system, alerting users to reverse flow conditions through audible alarms, text messages, or images, and providing instructions for correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If standard connectors are used for component connections, then ease of assembly and commercial compatibility are improved, but connection errors and reverse flow conditions increase

Engineering Contradiction:

Improveease of assemblyVSAvoidconnection accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary detection of connection correctness by monitoring temperature differentials across the humidifier before normal operation begins. The controller detects reverse flow conditions during a pre-operational check phase, allowing correction before patient treatment starts, thus preventing harmful effects while maintaining ease of assembly with standard connectors

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback through temperature sensors that continuously monitor the temperature differential across the humidifier. When reverse flow is detected (inlet temperature higher than outlet temperature), the controller provides feedback alerts to the user and can interrupt therapy, creating a closed-loop system that maintains connection accuracy without requiring proprietary connectors

Inventive Principle:

Principle #23Feedback

2Reliability

If proprietary connectors are used to prevent connection errors, then connection accuracy is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improveconnection accuracyVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical prevention approach (proprietary connectors requiring specific orientations) with a thermal detection system. Temperature sensors and controller algorithms substitute for mechanical design complexities, detecting reverse flow through temperature differential monitoring rather than preventing it through specialized connector geometry

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system monitors temperature parameters (inlet and outlet temperatures) to detect connection errors. By changing from mechanical prevention to thermal parameter monitoring, the system achieves connection accuracy detection without requiring complex proprietary connector designs, maintaining manufacturing simplicity

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If reverse flow detection is implemented, then patient safety and device protection are improved, but system complexity increases

Engineering Contradiction:

Improvepatient safetyVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The temperature sensors serve multiple functions: they monitor both the therapeutic effectiveness of humidification and detect reverse flow conditions. The controller integrates both treatment control and safety detection functions, reducing overall system complexity by making existing components multi-functional rather than adding dedicated detection hardware

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

Effectively detects and alerts users to incorrect connections, ensuring proper gas flow direction, maintaining optimal humidity and temperature delivery, and preventing device damage.

Implementation Method 1

a temperature sensor that detects a temperature at an inlet of the humidifier and a temperature at an outlet of the humidifier

Methodology Applied

Scientific EffectTemperature measurement:

Implementation Method 2

a heating element in the humidifier that heats a liquid to humidify the respiratory gas

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

a flow sensor that detects a flow rate of the respiratory gas through the humidifier

Methodology Applied

Scientific EffectFlow detection:

Data Source

PatentUS20250312547A1Method of detecting errors in the connections in a humidification system

Publication Date: 2025.10.09 FISHER & PAYKEL HEALTHCARE LTD

AI summary

Various control methods can indirectly determine incorrect connections between components in a respiratory therapy system. For example, errors in the connections can occur between a patient interface, a humidifier and/or a gases source. The methods can indirectly detect if a reverse flow condition exists or other error conditions. A reverse flow condition can occur when gases flows in a direction different from an intended direction of flow. The detection of the reverse flow condition can be indicative of likely errors in connections between the humidifier, patient interface and/or gases source.