Ambient-Air Bubble CPAP Respiratory Device with Blower Control

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Solution Overview

Problem

In remote or developing areas where wall sources for gas supply are not available, existing respiratory devices for bubble CPAP therapy are limited, requiring alternative solutions that can provide consistent gas flow and pressure control without relying on external gas sources.

Innovation Solution

A high flow respiratory apparatus with an integrated humidifier and blower that draws ambient air, capable of operating in bubble CPAP mode, using a flow generator to control motor speed for constant flow rates and pressure, and incorporating a controller for monitoring and adjusting pressure and flow parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wall source or gas cylinders are used to provide gas flow for bubble CPAP therapy, then reliable gas supply is ensured, but device complexity and cost increase, and portability is reduced

Engineering Contradiction:
Improvegas supply reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The respiratory device draws ambient air directly from the environment through an air inlet, eliminating the need for external gas sources. The integrated blower generates the required gas flow autonomously, and the integrated humidifier conditions the air independently, making the system self-sufficient and portable while maintaining reliable operation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent combines the blower, humidifier, and control system into a single integrated respiratory device. This merging of components reduces overall system complexity, eliminates the need for separate gas cylinders or wall connections, and maintains reliable gas supply through coordinated operation of integrated subsystems

Inventive Principle:
Principle #5Merging (Combining)

2Stability of the object's composition

If motor speed is increased to maintain constant flow rate during pressure excursions, then flow consistency is improved, but pressure control capability deteriorates

Engineering Contradiction:
Improveflow rate stabilityVSAvoidpressure control
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The controller dynamically adjusts motor speed based on real-time pressure feedback from the pressure sensor. When pressure exceeds the threshold, the controller reduces motor speed to lower pressure; when pressure is within acceptable range, the controller increases motor speed to maintain target flow rate. This dynamic adjustment resolves the contradiction by adapting motor speed to changing pressure conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs a feedback control mechanism where the pressure sensor continuously monitors pressure and sends signals to the controller. The controller compares actual pressure against the threshold and adjusts motor speed accordingly, creating a closed-loop system that simultaneously maintains flow stability and pressure control through continuous adaptation

Inventive Principle:
Principle #23Feedback

3Object-affected harmful factors

If pressure threshold is set low to protect patient, then patient safety is improved, but flow rate delivery capability deteriorates

Engineering Contradiction:
Improvepatient safetyVSAvoidflow rate delivery
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system dynamically adjusts motor speed based on the pressure threshold setting. When pressure approaches the threshold, motor speed is reduced to prevent excessive pressure buildup. When pressure is well below the threshold, motor speed is increased to deliver the required flow rate. This dynamic response allows the system to maintain both patient safety and effective flow delivery

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller modifies the motor operating parameters (speed) in response to pressure conditions. By changing the motor speed parameter dynamically, the system can operate at high speeds for efficient flow delivery when safe, and reduce speed when pressure approaches safety thresholds, thus resolving the contradiction between safety and productivity

Inventive Principle:
Principle #35Parameter changes

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

Enables reliable bubble CPAP therapy by controlling pressure and flow rates, reducing the need for external gas sources, ensuring consistent treatment delivery and reducing component complexity and cost.

Implementation Method 1

a blower configured to move ambient air to provide a flow of gas to the patient

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

a pressure sensor configured to measure a pressure of gas flow downstream of the blower

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP4349389B1A respiratory device for providing bubble cpap
Publication Date: 2025.08.27 FISHER & PAYKEL HEALTHCARE LTD
  • EP4349389B1 patent drawingFigure 1
  • EP4349389B1 patent drawingFigure 2
  • EP4349389B1 patent drawingFigure 3A

AI summary

Respiratory systems with a flow generator can provide bubble CPAP therapy by controlling the pressure of a flow of gas delivered to a patient. The controller of the respiratory system can control a motor speed of its flow generator so as to control the pressure of the flow of gas. The controller can also detect presence of bubbling and/or possible leaks in the gas pathway of the system. The respiratory system can include a high flow respiratory system.