Piezoelectric Stack Cage Isolates Thermal Expansion in Vibrating Tine Level Detection
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Solution Overview
Problem
Existing fluid level transducers face issues with rapid temperature changes, leading to fluctuations in compressive force on piezoelectric elements, causing malfunction or damage due to thermal expansion and contraction of the wall section, which compromises the integrity of the diaphragm and compression mechanism.
Innovation Solution
A vibrating element apparatus with a cage having outwardly biased legs fixed to the wall section, housing the compression device and piezoelectric stack within a hollow body, isolates the compression mechanism from axial expansion and contraction, maintaining consistent force and integrity by using a separate cage and braze-based fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wall section is made robust to provide mounting support, then structural integrity is improved, but the diaphragm thickness increases and energy consumption increases
Solution Approach 1:
The device is divided into separate functional components: a robust wall section for structural support, a thin diaphragm for vibration, and a cage structure for mounting the piezoelectric stack. This segmentation allows each component to be optimized for its specific function without compromising the others.
Solution Approach 2:
The cage structure acts as an intermediary between the wall section and the piezoelectric stack. It provides a stable mounting platform that is decoupled from thermal expansion effects, allowing the diaphragm to remain thin while maintaining structural integrity through the cage's support system.
2Device complexity
If the compression screw is directly mounted on the wall section, then device complexity is reduced, but thermal expansion causes compressive force fluctuations and malfunction
Solution Approach 1:
The cage structure serves as an intermediary mounting platform that isolates the compression screw from thermal expansion effects of the wall section. The cage is positioned within the hollow body and provides a stable reference frame that maintains consistent compressive force on the piezoelectric stack despite temperature changes.
Solution Approach 2:
The mounting system is segmented into the wall section, the cage structure, and the compression screw. This segmentation decouples the compression mechanism from thermal expansion, as the cage provides a stable mounting platform that is not directly affected by wall section expansion or contraction.
3Use of energy by moving object
If the diaphragm is made thin to reduce energy consumption, then energy efficiency is improved, but structural integrity and mounting stability deteriorate
Solution Approach 1:
The device is segmented into a thin diaphragm for vibration and a robust cage structure for support. This allows the diaphragm to be optimized for low energy consumption while the cage provides the necessary structural integrity and mounting stability.
Solution Approach 2:
The cage structure acts as an intermediary support system that provides mounting stability without requiring the diaphragm to be thick. The cage absorbs the structural support function, allowing the diaphragm to remain thin and energy-efficient.
4Device complexity
If the compression mechanism is directly attached to the expanding wall section, then device complexity is reduced, but rapid temperature changes cause compressive force reduction and malfunction
Solution Approach 1:
The cage structure serves as a thermal intermediary that decouples the compression mechanism from the wall section's thermal expansion. The cage provides a stable mounting platform that maintains consistent compressive force despite temperature-induced wall section expansion or contraction.
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 solution ensures the transducer maintains operational stability and prevents damage from temperature changes, allowing for a thin diaphragm with retained integrity and compatibility with existing outer bodies and electronics, ensuring reliable level detection across varying temperatures.
Implementation Method 1
the piezoelectric stack, located within the hollow body, and driven by a cycling voltage. When the vibrating tines come into contact with a fluid, there is a change in the frequency at which they vibrate.
Implementation Method 2
if the apparatus is subjected to a rapid change in temperature, the wall section, to which the diaphragm and plug are attached, will react to the change in temperature to a far greater extent that the components housed within the instrument. More particularly, if the environment is subjected to a sudden rise in temperature, the wall section will expand.
Implementation Method 3
If the temperature of the environment lowers rapidly, the wall section will contract. This will increase the compressive force applied to the piezo stack and may damage the crystals by crushing.
Data Source
Figure 1~2
AI summary
The invention describes a vibrating tine level detection device, and a method of forming the same, which is particularly suitable for operation in environments subject to rapid temperature change. A piezoelectric stack (15), which generates vibration of the tine (11), is located within a cage (18). The cage (18) is, in turn, located within a hollow body (14) defined by a diaphragm (6), from which the tines extend, and a wall section (7). The cage (18) is attached to the inside surface of the wall section (7), adjacent to the junction between the wall section (7) and the diaphragm (6). As a consequence, the ability of the cage (18) to maintain a substantially constant compression on the piezoelectric stack (15) is substantially unaffected by thermal expansion or contraction of the wall section (7).