Respiratory Gas Humidification Control With Upstream Humidity Sensing
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Solution Overview
Problem
Existing ventilation devices face challenges in maintaining precise and stable humidity levels in artificial ventilation, leading to dehydration or condensation issues, especially in unpredictable environments, due to the slow response of humidity control mechanisms and lack of accurate feedback.
Innovation Solution
A ventilation device with a humidity sensor arranged upstream of the humidification device to detect initial humidity levels, coupled with an ambient temperature sensor to correct for thermal losses, allowing for precise determination and adjustment of humidification needs, ensuring the breathing gas meets target humidity and temperature settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a humidification device with downstream humidity sensing is used, then the system can control humidity levels, but the response time is slow and control precision is insufficient
Solution Approach 1:
The humidity sensor is positioned upstream of the humidification device to detect the initial humidity state of the breathing gas before humidification occurs. This allows the control device to calculate the required humidification level in advance and adjust the heating element accordingly, eliminating the delay inherent in downstream sensing and creating a proactive control system that responds before humidity deviations occur.
Solution Approach 2:
The system implements a feedback control loop where the upstream humidity sensor continuously monitors the initial humidity state, the control device calculates the required humidification based on target humidity settings and sensor feedback, and the heating element adjusts in real-time to maintain precise humidity control throughout the breathing gas flow.
2Measurement precision
If ambient temperature variations are not compensated, then the device structure remains simple, but humidity control accuracy deteriorates in variable environmental conditions
Solution Approach 1:
An ambient temperature sensor provides continuous feedback on environmental temperature conditions. The control device uses this feedback to dynamically compensate for thermal effects on humidity measurement and evaporation rates, maintaining accurate humidity control across varying ambient temperatures without requiring complex mechanical adjustments.
Solution Approach 2:
The system dynamically adjusts control parameters based on ambient temperature readings. When ambient temperature changes are detected, the control device modifies the target humidity calculation and heating power delivery to account for altered evaporation characteristics and thermal losses, enabling accurate humidity control in variable environmental conditions through parameter adaptation rather than structural complexity.
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 configuration enables faster and more accurate control of breathing gas humidity, reducing the risk of dehydration or condensation, and maintaining optimal respiratory conditions even in variable environmental conditions, such as emergency situations.
Implementation Method 1
a variable-capacity evaporation device which is designed to increase the absolute humidity of the inspiratory respiratory gas flow
Implementation Method 2
a heating device with which the temperature of the inspiratory respiratory gas flow can be increased
Implementation Method 3
a cooling device with which the temperature of the inspiratory respiratory gas flow can be decreased
Data Source
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AI summary
The invention relates to a respiratory device (10) for the artificial respiration of a patient (12), comprising: - a respiration gas source assembly (15, 62), - a flow-changing device (16), - a humidifier device (38) which is designed to increase the value of the absolute humidity of the inspiratory respiration gas flow (AF), said humidifier device (38) having a liquid store (40) and an evaporation device (76) with a variable output for this purpose, - a respiration gas line assembly (30), - a proximal temperature sensor (48) which detects the temperature of the respiration gas flow (AF) in the proximal longitudinal end region (30a) of the respiration gas line assembly (30), - a humidity sensor assembly (66) which directly or indirectly detects the absolute humidity of the inspiratory respiration gas flow (AF), - a flow sensor (44), and - a controller (18) which is designed to control the operational output of the evaporation device (76) depending on a specified target humidity of the respiration gas and depending on signals of the proximal temperature sensor (48), the humidity sensor assembly (66), and the flow sensor (44). According to the invention, the humidity sensor assembly (66) is arranged upstream of the humidifier device (38) in the inspiratory direction of the respiration gas flow (AF) and detects the humidity state value upstream of the humidifier device (38), wherein the respiratory device (10) has at least one ambient temperature sensor (17) which detects the temperature in the surroundings (U) of the respiratory device (10), and the controller (18) controls the operational output of the evaporation device (76) depending on the ambient temperature as well.