Axial Guided Wave Liquid Level Sensing for Cryogenic Tanks
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Solution Overview
Problem
Traditional methods for measuring liquid level in liquid-hydrogen tanks aboard aircrafts are invasive, causing temperature and pressure fluctuations, which are undesirable in cryogenic environments.
Innovation Solution
A non-invasive liquid level sensing system utilizing an axial guided wave (AGW) transducer and a rod extending through an opening in the tank's inner wall, allowing for the transmission and reception of pulses without direct energy injection into the tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensing methods inject electric power into liquid-hydrogen tanks, then liquid level measurement is achieved, but temperature and pressure inside the tank increase
Solution Approach 1:
The patent introduces an intermediary rod that extends through the tank wall into the liquid hydrogen. The AGW transducer generates axial guided waves that travel through this rod to sense the liquid level. This intermediary structure allows the sensing function to be performed without direct energy injection into the tank, thus avoiding temperature and pressure increases while still achieving accurate liquid level measurement.
Solution Approach 2:
The patent replaces traditional electric power injection methods with axial guided wave (AGW) technology. Instead of using electrical energy that directly heats the liquid hydrogen, the system uses mechanical wave propagation through the rod to detect liquid level. This substitution of the sensing mechanism eliminates the harmful thermal effect while maintaining measurement capability.
2Measurement precision
If traditional sensing methods inject electric power into liquid-hydrogen tanks, then liquid level measurement is achieved, but pressure inside the tank increases
Solution Approach 1:
The rod serves as an intermediary that transmits axial guided waves from the AGW transducer into the liquid hydrogen environment. By using this mechanical wave transmission approach through the rod rather than direct electrical energy injection, the system achieves liquid level measurement without causing pressure increases inside the tank.
Solution Approach 2:
The patent substitutes traditional electrical sensing methods with axial guided wave-based mechanical sensing. The AGW transducer generates mechanical waves that travel through the rod, and changes in wave propagation characteristics indicate liquid level. This mechanical substitution avoids the pressure-increasing side effect of electrical power injection while maintaining accurate measurement.
3Object-affected harmful factors
If a rod extends through the tank wall for sensing, then non-invasive measurement is achieved, but device complexity increases
Solution Approach 1:
The rod serving as the waveguide also functions as the transmission medium for axial guided waves, combining structural support and sensing function in a single component. The AGW transducer integrates both wave generation and detection capabilities. This multi-functionality reduces the number of separate components needed, thereby limiting the increase in device complexity despite the addition of the rod extending through the tank wall.
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 effectively measures liquid level without affecting the temperature and pressure within the tank, ensuring safe and accurate monitoring of liquid-hydrogen levels.
Implementation Method 1
an axial guided wave (AGW) transducer, the AGW transducer including a sensing element and a rod operatively associated with the AGW transducer
Data Source
Figure 1a~1b
Figure 2a~3
Figure 4a~5b
AI summary
A liquid level sensing system (100) includes a sensing probe (102) including an axial guided wave (AGW) transducer (106), the AGW transducer (106) including a sensing element (108), and a rod (110) operatively associated with the AGW transducer (106), the AGW transducer (106) operatively connected to a first end (112) of the rod (110). The liquid level sensing system (100) includes a liquid tank (104), such that a second end (114) of the rod (110) extends through an opening (116) in an inner wall (118) of the liquid tank (104) into the liquid tank (104), the first end (112) of the rod (110) and the AGW transducer (106) being outside of the inner wall (118) of the liquid-hydrogen tank (104).