Fluid Sensor Thermal Oscillation Control
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Solution Overview
Problem
Existing fluid sensors face challenges in achieving precise measurements due to thermal oscillations and modulation, which can lead to inaccuracies in the measurement results, especially in miniaturized systems where small amounts of thermal energy can cause deformation and expansion of gases.
Innovation Solution
A fluid sensor design that incorporates two thermal emitters, one emitting thermal radiation at a specific power level during measurement intervals and the other during intermediate intervals, ensuring that the overall thermal oscillation or modulation remains at most ±50% throughout, thereby minimizing the impact of thermal oscillations on measurement results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single thermal emitter is used to provide thermal radiation during measurement intervals, then the measurement function is simple and device complexity is low, but thermal oscillations cause measurement precision to deteriorate
Solution Approach 1:
The single thermal emitter is divided into two separate thermal emitters (first thermal emitter and second thermal emitter). The first thermal emitter provides thermal radiation during measurement intervals, while the second thermal emitter provides thermal radiation during intermediate intervals. This segmentation allows each emitter to operate at reduced power levels, minimizing thermal oscillations and improving measurement precision while distributing the thermal provision function across multiple components.
Solution Approach 2:
The system implements periodic alternation between the first thermal emitter (active during measurement intervals) and the second thermal emitter (active during intermediate intervals). This periodic action ensures continuous thermal radiation provision while allowing the detection volume to thermally stabilize between measurement cycles, reducing thermal oscillations and enhancing measurement precision.
2Measurement precision
If thermal radiation power is increased to improve signal strength, then signal detection capability is improved, but thermal oscillation amplitude increases and measurement precision deteriorates
Solution Approach 1:
The thermal radiation provision function is segmented between two thermal emitters operating at reduced power levels. Each emitter operates at a lower power level than a single high-power emitter would require, reducing the amplitude of thermal oscillations in the detection volume while still providing sufficient thermal radiation for measurement during their respective active intervals.
Solution Approach 2:
By periodically alternating between two thermal emitters with reduced individual power levels, the system maintains continuous thermal radiation while reducing peak thermal oscillation amplitudes. The periodic switching allows the detection volume to thermally stabilize between emissions, improving measurement precision by reducing thermal modulation effects.
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 approach allows for precise measurement results by maintaining a consistent operating temperature within a narrow tolerance range, reducing the influence of thermal oscillations and enhancing the accuracy of fluid sensors, particularly in miniaturized systems.
Implementation Method 1
a first thermal emitter (14) arranged in the housing and configured to emit first thermal radiation (18) into a detection volume (24) of the housing, which contains a measurement gas (26), at a first power level during a measurement interval
Implementation Method 2
Photoacoustic sensors (PAS) may have an infrared emitter (signal source) and a measuring element (signal sink), between which an absorption path is arranged. Thermal radiation can be transmitted from the emitter to the measuring element through the absorption path, with some of the thermal radiation being manipulated or absorbed in the absorption path by a gas situated there
Implementation Method 3
a second thermal emitter (16) arranged in the housing and embodied to emit second thermal radiation (22) at a second power level into the detection volume (24) during the intermediate interval such that a thermal oscillation of thermal radiation in relation to an overall power level of the thermal radiation in the detection volume (42), which is based on a sum of the first power level and the second power level, is at most ∓50%
Data Source
AI summary
A fluid sensor includes a housing and a thermal emitter in the housing to emit first thermal radiation into a detection volume of the housing at a first power level during a measurement interval and emit the first thermal radiation at a reduced first power level or not emit said first thermal radiation at all during an intermediate interval disposed outside of the measurement interval. The fluid sensor includes a measuring element in the detection volume to receive a radiation signal during the measurement interval. The fluid sensor includes a second thermal emitter in the housing to emit second thermal radiation at a second power level into the detection volume during the intermediate interval such that a thermal oscillation of thermal radiation in relation to an overall power level of the thermal radiation in the detection volume is at most ±50% during the measurement interval and the intermediate interval.