Roughened Condensation Surface for Hydrocarbon Dew Point Sensor
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Solution Overview
Problem
Existing hydrocarbon dew point sensors are complex, expensive, and prone to contamination, with limited accuracy when determining the dew point in hydrocarbon gases due to the use of smooth condensation surfaces that result in small contact angles and incomplete light intensity changes upon condensation.
Innovation Solution
A sensor with a roughened condensation surface that uses an increase in reflected light intensity as a criterion for dew point detection, eliminating the need for a voluminous measurement chamber and reducing sensitivity to contamination, featuring a transparent body with a planar measurement surface and a light source for illuminating the condensation surface, a light detector for measuring intensity changes, and a temperature adjustment mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a smooth condensation surface is used, then the sensor structure is simple, but the light intensity change upon condensation is insufficient leading to poor measurement accuracy
Solution Approach 1:
The condensation surface is given a specific roughness profile with controlled parameters (Ra 0.1-10 μm, Rz 0.5-50 μm) to create local optical effects. This local quality change enables strong light intensity modulation when hydrocarbon condensate forms on the rough surface, solving the measurement accuracy problem without requiring complex device modifications.
Solution Approach 2:
The optical properties of the condensation surface are modified by changing its physical parameters - specifically introducing controlled roughness characteristics. This parameter change transforms the surface from optically smooth to optically active, creating sufficient light intensity changes for accurate dew point detection while maintaining a relatively simple sensor structure.
2Reliability
If light is guided through a voluminous measurement chamber, then the measurement path is sufficient, but the device becomes complex and sensitive to contamination
Solution Approach 1:
The measurement function is extracted from a voluminous measurement chamber and concentrated onto a small condensation surface area. By taking out the essential measurement interaction (light-condensate-gas) and confining it to a compact surface region, the device achieves contamination resistance and compactness while maintaining measurement capability.
Solution Approach 2:
The measurement approach transitions from a three-dimensional volumetric measurement chamber to a two-dimensional surface-based measurement. By moving the measurement interaction to the condensation surface plane, the device eliminates the need for a large measurement volume while maintaining sufficient optical path length for accurate detection.
3Measurement precision
If a roughened condensation surface is used, then light intensity changes significantly upon condensation, but the manufacturing precision requirements increase
Solution Approach 1:
Instead of requiring precise control of complex surface geometries, the solution changes the manufacturing parameters to focus on controlling two key roughness parameters (Ra and Rz) within specified ranges. This parameter simplification makes the manufacturing process more controllable while achieving the desired optical effects for accurate dew point measurement.
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 sensor provides a compact, reliable, and cost-effective method for determining hydrocarbon dew points with enhanced accuracy by utilizing the roughened surface to create artificial droplets or ice crystals, resulting in significant light intensity changes upon condensation, enabling continuous dew point determination.
Implementation Method 1
a condensation surface (12) with a condensation dependent reflectivity
Implementation Method 2
the light intensity reflected back into the transparent body from the condensation surface is determined
Data Source
AI summary
The invention relates to a method and a sensor for determining the hydrocarbon dew point in a gas, in particular in a gaseous fuel. According to the invention a roughened condensation surface is provided on a planar measurement surface of a transparent body. Light is shone onto the roughened condensation surface through the transparent body and the intensity of the light reflected back into the transparent body is measured. The hydrocarbon dew point temperature can be inferred from changes in the intensity of the light which is reflected back when heating or cooling the condensation surface.