Piezoelectric Liquid Feeding Control for Helmholtz Vibration Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid feeding apparatuses using piezoelectric elements suffer from residual vibrations at the Helmholtz frequency, leading to inefficiencies in liquid feeding due to overlapping vibrations during capacity changes, particularly affecting smaller liquid feeding chambers and resulting in reduced liquid feeding efficiency.
Innovation Solution
A driving method for a liquid feeding apparatus that controls the voltage applied to a piezoelectric element to alternate between application and non-application during specific periods, using a pulse driving technique with a duty ratio of 1:1, effectively suppressing residual vibrations by adjusting the on and off periods to minimize the impact of Helmholtz frequency vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a piezoelectric element is used to circulate liquid in a liquid feeding apparatus, then liquid feeding capability is achieved, but residual vibrations at Helmholtz frequency occur during capacity changes
Solution Approach 1:
The patent applies periodic pulsed driving to the piezoelectric element, where voltage is applied in discrete pulses rather than continuously. The driving element is activated during specific periods (first period) and left off during other periods (second period), creating a periodic action that prevents continuous vibration buildup and suppresses residual vibrations at the Helmholtz frequency, thereby improving liquid feeding efficiency
Solution Approach 2:
The patent dynamically adjusts the driving state of the piezoelectric element by switching between applied and non-applied voltage states. The control unit dynamically controls the on/off timing based on the operating conditions, allowing the system to adapt to different liquid feeding requirements while maintaining suppression of harmful vibrations
2Productivity
If voltage is continuously applied to the piezoelectric element, then liquid circulation is maintained, but residual vibrations overlap during capacity changes reducing efficiency
Solution Approach 1:
The patent implements periodic pulsed driving where voltage is applied only during specific first periods and left off during second periods. This periodic action allows the piezoelectric element to settle and avoid continuous vibration overlap, reducing energy loss while maintaining effective liquid circulation during the active periods
Solution Approach 2:
The patent extracts the harmful continuous voltage application and replaces it with intermittent pulsed voltage. By taking out the continuous driving and applying voltage only in discrete pulses, the system eliminates the energy loss associated with continuous vibration overlap while preserving the essential liquid feeding function during the pulsed intervals
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
This approach enhances liquid feeding efficiency by reducing residual vibrations, resulting in a 1.3 to 1.5 times improvement in liquid feeding efficiency compared to traditional methods, while maintaining a simple and cost-effective circuit configuration.
Implementation Method 1
a piezoelectric element in a membrane shape is used as a driving source, and the piezoelectric element is caused to function as a pump by changing a voltage applied to the piezoelectric element asymmetrically with respect to time
Implementation Method 2
there have been proposed liquid feeding apparatuses designed to feed a liquid in the order of micrometers... taking advantage of a characteristic of flow channel resistance in which the flow channel resistance changes non-linearly with respect to a flow velocity
Data Source
AI summary
A driving method enables a liquid feeding apparatus using a driving element in a membrane shape to feed a liquid at high liquid feeding accuracy. To this end, a voltage applied to the driving element is controlled in such a way as to repeat a first period in which a first voltage is applied and a second period which is a longer period than the first period and used to effect a change between the first voltage and a second voltage lower than the first voltage, and in such a way as to switch between application and non-application of the first voltage during the first period.