Disk-Shaped Cavity Pump for High Acoustic Pressure Generation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fluid pumps, particularly those with cylindrical cavities, face limitations in generating high amplitude pressure oscillations due to radial pressure oscillations not being effectively employed, leading to large device sizes and sensitivity to resonance tuning.
Innovation Solution
A fluid pump with a substantially disk-shaped cavity and a piezoelectric disk actuator operating at high frequencies, causing radial oscillations and achieving high acoustic pressure through geometric amplification, while being less sensitive to resonance shifts and temperature fluctuations, and designed for compact micro-device applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a cylindrical cavity with acoustic driver is used, then fluid pumping is achieved, but the acoustic pressure wave has limited amplitude
Solution Approach 1:
The patent transitions from conventional cylindrical cavities to a disk-shaped cavity geometry, fundamentally changing the dimensional characteristics. This geometric transformation enables radial pressure oscillations to be effectively employed, achieving high amplitude acoustic pressure waves (exceeding 10 atm) that were not possible in traditional cylindrical configurations, thereby significantly enhancing the pumping effect
2Stress or pressure
If varying cross-section cavities (cone, horn-cone, bulb) are used to achieve high amplitude pressure oscillations, then pumping effect is significantly increased, but the device complexity increases
Solution Approach 1:
The patent employs a disk-shaped cavity with asymmetric geometry characterized by a large aspect ratio (radius much greater than height). This asymmetric configuration enables high amplitude radial pressure oscillations while maintaining manufacturing feasibility. The specific geometric parameters (radius a, height h satisfying a/h > 10) create the necessary conditions for high amplitude acoustic resonance without requiring complex varying cross-sections like cones or bulbs
3Speed
If low frequency drive mechanism with electromechanical armature and steel diaphragm is used, then radial acoustic oscillations are generated, but the overall size of the compressor becomes large
Solution Approach 1:
The patent replaces the complex electromechanical drive system (armature, leaf spring suspension, vibration mounts) with a compact piezoelectric actuator. This substitution enables high frequency operation (500-5000 Hz) while dramatically reducing the overall device size. The piezoelectric actuator directly couples to the disk cavity, eliminating the need for large mechanical resonance components and noise enclosures required in low frequency systems
4Stress or pressure
If high Q factor resonance is used to achieve high pressures, then pressure amplitude is increased, but the system becomes very sensitive to tuning shifts from temperature fluctuations or load changes
Solution Approach 1:
The patent employs active frequency tracking and control mechanisms that dynamically adjust the drive frequency to follow the resonant frequency of the disk cavity. This dynamic adaptation compensates for temperature-induced frequency shifts and load variations, maintaining optimal resonance conditions and high pressure amplitude (exceeding 10 atm) without the excessive sensitivity characteristic of high Q factor systems. The system continuously monitors and adjusts operating parameters to maintain peak performance
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 enables the generation of high acoustic pressure with reduced device size and increased robustness against resonance tuning variations, suitable for micro-device applications with a compact cavity volume and low compression ratio.
Implementation Method 1
the actuator causes oscillatory motion of one or both end walls in a direction substantially perpendicular to the plane of the end walls; wherein the cavity radius, a, and height, h, satisfy the following inequalities
Implementation Method 2
the actuator causes oscillatory motion of one or both end walls in a direction substantially perpendicular to the plane of the end walls; whereby, in use, the axial oscillations of the end walls drive radial oscillations of fluid pressure in the cavity
Implementation Method 3
achieving high acoustic pressure through geometric amplification, while being less sensitive to resonance shifts and temperature fluctuations
Data Source
Figure 1~2D
Figure 3A~4
Figure 5A~6B
AI summary
A fluid pump comprising one or more actuators, two end walls, a side wall; a cavity which, in use, contains fluid, the cavity having a substantially cylindrical shape bounded by the end walls and the side walls, at least two apertures through the cavity walls, at least one of which is a valved aperture, wherein the cavity radius, a, and height, h, satisfy the following inequalities: a/h is greater than 1.2; and h2/a is greater than 4 x 10-10m; and wherein, in use, the actuator causes oscillatory motion of one or both end walls in a direction perpendicular to the plane of the end walls; whereby, in use, the axial oscillations of the end walls drive radial oscillations of fluid pressure in the cavity.