Piezoelectric Liquid Level Sensor with Non-Tilting Coupling Pad
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Solution Overview
Problem
Existing devices for measuring liquid levels in containers, particularly those using piezoelectric elements, face accuracy issues due to incorrect orientation and the inability to distinguish between liquid and gas effectively, leading to false measurements.
Innovation Solution
A handheld device with a piezoelectric element and a non-tilting coupling pad, chemically bonded to ensure correct orientation, generates vibrations that differentiate between oscillations propagating within the container's shell and those through a liquid or gas, using a low-pass filter to accurately determine liquid levels by analyzing echo patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the piezoelectric element is pressed against the container wall at any orientation, then the device is easy to operate, but measurement accuracy deteriorates due to incorrect orientation
Solution Approach 1:
The coupling pad is designed with an asymmetric shape that only properly couples to the container wall when the device is oriented perpendicular to the surface. This asymmetric geometry ensures that only correct orientation allows effective vibration transmission, thereby improving measurement accuracy while maintaining ease of operation through intuitive proper alignment.
Solution Approach 2:
A non-tilting element is introduced as an intermediary component between the coupling pad and the container wall. This element acts as a mediator that constrains the coupling pad to maintain perpendicular orientation to the container wall, preventing tilting and ensuring accurate measurement while allowing the device to be easily applied to the container surface.
2Measurement precision
If the device distinguishes between oscillation types, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The device uses mechanical vibrations generated by the piezoelectric element to detect liquid level. By analyzing the vibration patterns and echo returns through the container wall, the system distinguishes between oscillations propagating through liquid versus gas, achieving accurate measurement using purely mechanical principles without complex electronic systems.
Solution Approach 2:
The patent replaces complex electronic sensing systems with a mechanical vibration-based detection system. The piezoelectric element generates mechanical vibrations that propagate through the container wall and liquid, with the echoes being detected and analyzed mechanically, simplifying the overall device architecture while maintaining high measurement accuracy.
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 device significantly increases measurement accuracy by ensuring correct orientation and effectively distinguishing between liquid and gas, reducing false readings and improving reliability in determining liquid levels.
Implementation Method 1
a piezoelectric element (8) adapted for generating vibrations when energized
Implementation Method 2
a coupling pad (7) which is bonded to the piezoelectric element (8) for transmitting the vibrations to a surface of the container (1)
Implementation Method 3
oscillations generated within the container by the vibrations propagate through the liquid. These oscillations are reflected at the inner wall of the container
Implementation Method 4
As the gas dampens these oscillations, hardly any reflected oscillations will reach the wall where the measuring device is placed
Data Source
AI summary
A device for measuring the level of a liquid within a container, in particular the level of liquid gas, comprises a housing and a piezoelectric element adapted for generating vibrations when energized. A coupling pad is provided which is bonded to the piezoelectric element for transmitting the vibrations to a surface of the container. Further, a non-tilting element is provided which surrounds the coupling pad. A method for measuring the level of liquid within a container uses a piezoelectric element for generating vibrations which are transmitted into the shell of the container. An analyzing strategy is used which distinguishes between normal post-pulse oscillations of the piezoelectric element after a measurement was triggered, and extended post-pulse oscillations which are the result of echoed oscillations in the shell of the container.