Humidifier Startup Control for Sleep Apnea Water Management
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Solution Overview
Problem
Current humidifiers in airway pressure support systems for sleep apnea patients do not effectively manage the startup process, leading to inefficient heating and potential issues with water evaporation, which can result in discomfort and reduced effectiveness in maintaining airway patency.
Innovation Solution
A method for operating a humidifier coupled to a gas flow generator, involving a pump that supplies water to a heater plate, with a controlled temperature increase and duty cycle adjustment based on temperature monitoring, ensuring efficient water evaporation and minimizing the risk of water being blown into the patient interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heater plate is heated to high temperature immediately at startup, then water evaporation efficiency is improved, but water may be blown into the patient interface causing discomfort
Solution Approach 1:
The heater plate is pre-heated to a first temperature (e.g., 50°C) before the pump is activated to deliver water. This preliminary heating action ensures that when water is introduced, it immediately begins to evaporate efficiently without being blown into the patient interface as liquid droplets.
Solution Approach 2:
The heating process occurs in distinct phases: first heating to a lower temperature, then after pump activation, heating to a higher temperature. This periodic or staged heating approach allows the system to transition from a safe startup phase to an efficient operation phase without the harmful effects of immediate high-temperature heating.
2Productivity
If the pump duty cycle is increased immediately at startup, then humidification effectiveness is improved, but heating efficiency decreases due to insufficient heat transfer
Solution Approach 1:
The heater plate is pre-heated to a specific temperature before the pump is activated. This preliminary action ensures that the heating element is ready to efficiently transfer heat to water immediately when water delivery begins, maximizing heating efficiency from the start of humidification.
Solution Approach 2:
The system monitors the temperature of the heater plate and uses this feedback to control the pump duty cycle. The pump is activated only when the heater plate reaches the predetermined temperature, ensuring optimal conditions for heat transfer and energy efficiency.
3Productivity
If the heater plate temperature is raised quickly, then water evaporation rate is improved, but temperature control precision deteriorates
Solution Approach 1:
The heating process is divided into stages with different target temperatures. The system first heats to a lower temperature, activates the pump, then heats to a higher temperature. This staged approach allows for better temperature control at each phase while achieving high evaporation rates in the final phase.
Solution Approach 2:
The system continuously monitors heater plate temperature and adjusts heating power accordingly. By using feedback control with predetermined temperature thresholds, the system maintains precise temperature control while still achieving rapid evaporation when needed.
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
This solution ensures efficient heating and evaporation of water, reducing discomfort and improving airway patency maintenance, while minimizing the risk of water entering the patient interface, thus enhancing the overall effectiveness of the humidification process.
Implementation Method 1
raising the temperature of the heater plate from an ambient temperature to a first predetermined temperature
Implementation Method 2
efficient heating and evaporation of water
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A method for operating a humidifier (12) coupled to a gas flow generator. The humidifier has a pump (24) providing a supply of water (20) to a heater plate (28). The method includes: providing power to the gas flow generator; raising the temperature of the heater plate from an ambient temperature to about a first predetermined temperature; powering the pump at about a predetermined first duty cycle; monitoring the temperature of the heater plate until one of: a drop in temperature is detected, or a predetermined period of time has elapsed; and one of: increasing the duty cycle of the pump if the drop in temperature is detected, or turning off the pump if the predetermined period of time has elapsed.