Automated Drop Counter for Jet Fuel Thermal Oxidation Testing
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Solution Overview
Problem
Current methods for testing thermal oxidation stability of aviation fuels, such as ASTM D3241, rely on subjective visual evaluation of deposits and manual flow rate measurement, which are prone to inaccuracies and errors due to the slow flow rate of fuel, leading to potential misassociation of data with the wrong heater tube or fuel batch.
Innovation Solution
An automated drop counter and flow meter system that uses an infrared LED and photodiode pair to accurately count fuel drops and measure flow rate, controlled by an embedded computer, ensuring precise measurement and minimizing human error by integrating a sample drive pump and pressure control to maintain consistent conditions during the test.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual flow rate measurement is used, then device complexity is reduced, but measurement precision deteriorates due to slow flow rate and human error
Solution Approach 1:
The patent replaces manual mechanical flow rate measurement with an automated optical detection system using an infrared LED and photodiode to count fuel drops. This substitution eliminates human error and provides precise automated measurement of slow flow rates, directly resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If visual evaluation of deposits is used, then ease of operation is improved, but measurement precision deteriorates due to subjective evaluation
Solution Approach 1:
The patent replaces subjective visual evaluation with an electronic video tube deposit rater that uses optical sensors and image processing to objectively measure deposit formation. This automated system eliminates human subjectivity while maintaining operational simplicity through computer-controlled analysis.
3Reliability
If data is maintained separately from heater tube, then ease of repair is improved, but reliability deteriorates due to potential misassociation of data
Solution Approach 1:
The patent merges the data storage system with the heater tube assembly by implementing an embedded computer within the heater tube that automatically records and stores test data. This integration ensures data is always associated with the correct heater tube and fuel batch, eliminating misassociation errors while maintaining system maintainability.
4Measurement precision
If automated drop counter and flow meter are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements an automated drop counter using an infrared LED and photodiode pair that optically detects and counts fuel drops. This optical system replaces complex mechanical flow measurement devices, providing high precision measurement while actually reducing mechanical complexity through non-contact sensing.
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 system provides accurate and objective measurements of fuel flow rate and deposit formation on a heated surface, reducing the risk of errors and ensuring reliable data association, thus enhancing the reliability of thermal oxidation stability testing.
Implementation Method 1
an infrared LED and photodiode pair to accurately count fuel drops and measure flow rate
Data Source
AI summary
A thermal oxidation tester is shown for determining thermal stability of a fluid, particularly hydrocarbons when subjected to elevated temperatures. The tendency of the heated fluid to oxidize and (1) form deposits on a surface of a heater tube and (2) form solids therein, are both measured at a given flow rate, temperature and time. The measured results are used to determine whether a fluid sample passes or fails the test. Sample flow rate is important in the jet fuel thermal oxidation test. Current practice requires manual drop counting or flow confirmation with the use of volumetric glassware. An apparatus is described to precisely measure the flow rate and automatically perform flow rate check using a drip rate method and/or volumetric method.