Free-Standing Thermal Membrane Flow Sensor for Condensation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing flow sensors face challenges in accurately measuring fluid flow parameters, particularly in respiratory gas measurement, due to condensation issues when the gas is 100% saturated with water, leading to signal interference and potential system failures during ventilation.
Innovation Solution
A flow sensor design featuring a free-standing thermal membrane sensor element with an integrated condensate heater, allowing the sensor chip to operate independently in the fluid flow, preventing condensation and maintaining accurate measurements by evaporating any condensate that forms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sensor chip is integrated into a probe or housing structure, then mechanical protection and structural stability are improved, but condensation accumulates on the sensor surface leading to measurement errors and signal collapse
Solution Approach 1:
The sensor chip is extracted from the integrated probe structure and positioned as a free-standing element in the fluid flow path. This extraction eliminates the enclosed space where condensation could accumulate, allowing the sensor to remain exposed to the main flow while preventing water drop formation that would otherwise occur in integrated housing structures.
Solution Approach 2:
The temperature of the sensor chip is actively controlled and maintained above the dew point temperature of the fluid. By changing the thermal parameter (temperature) of the sensor surface, condensation is prevented from forming, thereby maintaining measurement reliability while the sensor remains structurally protected.
2Use of energy by moving object
If the sensor operates at temperatures below the dew point, then energy consumption is reduced and component stress is minimized, but condensation forms on the sensor surface causing signal interference and measurement failure
Solution Approach 1:
The sensor chip is pre-heated and maintained above the dew point temperature before condensation can occur. This preliminary thermal action prevents water vapor from condensing on the sensor surface, ensuring continuous reliable measurements without the need for post-condensation removal operations.
Solution Approach 2:
The temperature control system continuously maintains the sensor chip temperature above the dew point throughout operation. This continuous thermal action ensures that condensation never forms on the sensor surface, providing uninterrupted reliable measurements while managing energy consumption through efficient thermal regulation.
3Reliability
If a condensate heater is integrated into the sensor chip, then condensation prevention capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The condensate heater is merged with the sensor chip structure, integrating the heating function directly into the sensing element. This combination eliminates the need for separate heating components and control systems, reducing overall device complexity while maintaining effective condensation prevention capability.
Solution Approach 2:
The sensor chip is designed to perform multiple functions: flow parameter sensing and condensation prevention through integrated heating. By making the sensor chip multi-functional, the need for separate dedicated condensation control components is eliminated, simplifying the overall device structure while maintaining reliable operation.
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 enables reliable and precise flow parameter determination across a large measuring range with reduced error rates, even in conditions where condensation might occur, ensuring continuous and accurate fluid flow measurement.
Implementation Method 1
thermal membrane sensor element which is designed to determine a flow parameter of the fluid
Implementation Method 2
the sensor chip is heated by means of a condensate heater arranged on the sensor chip above a condensation temperature of a condensable substance contained in the gas, in order to remove condensate which has formed on the sensor chip
Implementation Method 3
the sensor chip is heated by means of a condensate heater arranged on the sensor chip above a condensation temperature
Data Source
AI summary
A flow sensor for determining a flow parameter of a fluid is shown in embodiment examples of the present invention, comprising a sensor chip, which has at least one thermal membrane sensor element, which is designed to determine the flow parameter of the fluid in a measurement region or to determine a fluid temperature of the fluid, wherein the thermal membrane sensor element has two thermocouple junctions arranged at a distance from each other and a heating element arranged between the thermocouple junctions, and wherein the sensor chip is designed for the fluid to flow around the sensor chip as a freestanding sensor finger during the operation of the flow sensor.