Vibrating Perforate Membrane Spray System Pressure Control
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Solution Overview
Problem
Existing perforate membrane droplet generation devices face challenges in minimizing liquid loss through evaporation, preventing leakage due to atmospheric changes, ensuring consistent atomization, and allowing for multi-orientation use without increasing costs or complexity, especially for portable devices that require long-term fluid dispensing.
Innovation Solution
A droplet generation device with a split reservoir and a pressure control system that includes a gas-permeable membrane and a hydrophobic coating on the perforate membrane, allowing for venting and pressure equalization, ensuring the liquid is at or slightly below atmospheric pressure, and enabling a master-cartridge design for cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid pressure is maintained at or slightly below atmospheric pressure for proper atomization, then spray performance is improved, but liquid loss through evaporation increases
Solution Approach 1:
The reservoir is divided into a liquid-filled region and a gas-filled region separated by a gas-permeable membrane. This segmentation allows the liquid region to maintain near-atmospheric pressure for proper atomization while the gas region can be pressurized to prevent evaporation, resolving the contradiction between spray performance and liquid loss prevention.
Solution Approach 2:
The gas-permeable membrane acts as an intermediary between the liquid-filled region and the gas-filled region. It allows gas to pass through to equalize pressure while blocking liquid, enabling the liquid to remain at atmospheric pressure for atomization while the gas pressure in the other region prevents evaporation.
2Adaptability or versatility
If the device is designed for multi-orientation use, then versatility is improved, but leakage risk increases due to atmospheric pressure changes
Solution Approach 1:
The system dynamically adjusts pressure parameters in response to atmospheric changes and orientation. The gas-permeable membrane allows pressure equalization with the environment, and the flexible membrane can deform to accommodate pressure changes, preventing leakage while maintaining multi-orientation capability.
Solution Approach 2:
The flexible membrane separating the liquid and gas regions can deform and adapt to different orientations and pressure changes. This flexibility allows the device to maintain seal integrity across multiple orientations while accommodating atmospheric pressure variations, preventing leakage.
3Loss of substance
If a sealed reservoir is used to prevent evaporation, then liquid loss is reduced, but pressure buildup from atmospheric changes causes leakage
Solution Approach 1:
The gas-permeable membrane is a porous material that allows gas molecules to pass through while blocking liquid. This enables the reservoir to maintain a sealed environment to prevent evaporation while allowing pressure equalization with the atmosphere to prevent leakage from pressure buildup.
Solution Approach 2:
The system dynamically responds to atmospheric pressure changes through the gas-permeable membrane. When external pressure changes, gas can flow through the membrane to equalize pressure, preventing leakage while maintaining the sealed reservoir environment to prevent evaporation.
4Reliability
If pressure control valves are added to manage liquid pressure, then atomization performance is improved, but device complexity increases
Solution Approach 1:
The gas-permeable membrane creates a self-regulating pressure control system. Gas automatically flows through the membrane to equalize pressure between the liquid and gas regions, eliminating the need for external pressure control valves and reducing device complexity while maintaining reliable pressure control.
Solution Approach 2:
The gas-permeable membrane serves as a passive intermediary that automatically regulates pressure without requiring active control components. It allows gas to pass through to equalize pressure while blocking liquid, providing pressure control functionality without adding valves or complex control systems.
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 effectively reduces evaporation loss, prevents leakage across various environmental conditions, ensures reliable atomization, and allows for multi-orientation use while maintaining cost-effectiveness and simplicity, making it suitable for portable devices.
Implementation Method 1
a gas-permeable membrane separating the liquid-filled region from the gas-filled region
Implementation Method 2
The perforate membrane is coated with a hydrophobic material
Implementation Method 3
vibration of the membrane causes the liquid to be ejected through the perforate membrane
Data Source
AI summary
A droplet generation device comprising a reservoir split into at least two regions by a substantially liquid impermeable barrier, a perforate membrane connecting one of said regions, containing, in use, the liquid to be dispensed, to the atmosphere, such that vibration of the membrane causes the liquid to be ejected through the perforate membrane into the atmosphere, and a pressure control system consisting of one or more valves in which at least one valve vents gas into the reservoir in response to a pressure difference, ΔPin, across it that is less than zero, and at least one valve is connected to a non-liquid-containing region of the reservoir and vents gas out of the reservoir in response to a pressure difference, ΔPout, across it that is greater than ΔPin, where ΔPin and ΔPout are the absolute pressure of the gas in the reservoir minus the absolute atmospheric pressure outside of the reservoir.