External Sensor Gas Conduit for Humidified Therapy
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Solution Overview
Problem
Existing systems for delivering heated, humidified gases for therapeutic purposes face challenges in accurately controlling temperature, humidity, and flow rates due to interdependent characteristics, which are difficult to maintain over varying ambient conditions, leading to issues like condensation and sensor vulnerability during cleaning.
Innovation Solution
A sensor arrangement is embedded in or on the outside wall of the gas conduit, with a controller estimating gas properties and compensating for system conditions, allowing for effective control of gas delivery without protruding sensors, thus preventing damage and facilitating cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor protrudes into the gas flow path to directly measure gas properties, then measurement precision is improved, but the sensor becomes vulnerable to damage during cleaning and more difficult to manufacture
Solution Approach 1:
The sensor is moved from the internal gas flow path to the external surface of the conduit wall, changing its spatial dimension from inside to outside. This allows the sensor to measure gas properties through the wall without protruding into the flow path, thereby maintaining measurement precision while eliminating vulnerability to damage during cleaning operations.
Solution Approach 2:
The conduit wall acts as an intermediary medium between the sensor and the gas flow. The sensor measures the external surface temperature of the wall, which serves as a proxy for the internal gas temperature, eliminating the need for direct contact between the sensor and the gas stream.
2Measurement precision
If a sensor protrudes into the gas flow path to directly measure gas properties, then measurement precision is improved, but ease of operation during cleaning is worsened
Solution Approach 1:
The sensor is repositioned from the internal dimension (protruding into the flow path) to the external dimension (mounted on the outer surface of the conduit wall). This dimensional change completely removes the sensor from the cleaning path, allowing unobstructed access to the entire internal surface of the conduit for thorough cleaning operations.
3Reliability
If sensors are embedded in the conduit wall to protect them, then sensor reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The sensing function is segmented from the conduit structure, with the sensor mounted on the external surface rather than being embedded within the wall thickness. This segmentation eliminates the need for precise embedding operations during manufacturing, as the sensor can be attached to the external surface after conduit fabrication.
4Ease of operation
If the system uses external sensors to estimate internal gas properties, then ease of operation for cleaning is improved, but measurement precision may be compromised
Solution Approach 1:
The system employs feedback control where the external sensor continuously monitors the outer surface temperature of the conduit wall, and the controller uses this information to estimate the internal gas temperature and adjust heating elements accordingly. This feedback loop compensates for the indirect measurement approach, maintaining measurement precision while enabling easy cleaning access.
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
The solution ensures precise control of gas characteristics, reduces sensor damage, and allows for easier conduit cleaning, maintaining effective therapy delivery despite ambient variations.
Implementation Method 1
a sensor embedded in or on the outside wall of the passage... receiving an output of the sensor and adapted to derive from the output of the sensor an estimation of a property of gases flowing through the passage
Data Source
AI summary
An apparatus for the supply of humidified gases to a patient is disclosed that comprises a gases supply passage downstream of a humidified gases supply, and upstream of a patient in use, where at least one sensor is embedded in or located on the outside of the wall of the passage. In preferred forms the wall of the passage divides the sensor(s) from a flow of gases in the passage. In use, a controller receives an output of the sensor(s) and derives from the output of the sensor(s) an estimation of a property of gases flowing through the passage or provides a control output to the humidified gases supply according to the output of the sensor(s).