Flat Sheet Electrospray Emitter for Manufacturing and Cleaning
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Solution Overview
Problem
Existing electrospray devices based on capillaries are difficult to manufacture, handle, and clean, especially when produced in large numbers, due to their complex structure and susceptibility to dirt and debris accumulation.
Innovation Solution
An electrospray emitter design featuring a flat sheet with a channel opening to an aperture, incorporating a charging electrode and a control electrode for controlling electrospray emission, along with a non-wetting layer to prevent liquid buildup and facilitate cleaning, and a guard electrode to reduce cross-talk between emitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If capillary-based electrospray devices are used, then electrospray function is achieved, but manufacturing difficulty and cleaning difficulty increase
Solution Approach 1:
The device is segmented into distinct functional layers: a substrate layer, a non-wetting layer, and an electrode layer. This segmentation allows each layer to be optimized independently and simplifies manufacturing processes compared to monolithic capillary structures.
Solution Approach 2:
The patent replaces the mechanical capillary structure with a planar substrate-based system where liquid flows through channels on a flat surface. This substitution eliminates the complex three-dimensional capillary geometry, making manufacturing and cleaning significantly easier.
2Ease of operation
If capillary-based electrospray devices are used, then electrospray function is achieved, but cleaning difficulty increases due to dirt and debris accumulation
Solution Approach 1:
A non-wetting layer is applied specifically to the emitter surface and channel regions where liquid contact occurs. This localized application of hydrophobic material prevents liquid buildup and facilitates cleaning without affecting other device regions.
Solution Approach 2:
The patent converts the potential harm of liquid accumulation (which causes dirt and debris buildup) into a benefit by using non-wetting surfaces. The hydrophobic property causes liquid to be repelled and easily removed, transforming a cleaning problem into an ease-of-maintenance feature.
3Ease of operation
If control electrode is placed on emitter surface, then electrospray control is improved, but contamination risk increases
Solution Approach 1:
The non-wetting layer serves as an intermediary between the control electrode and the emitter surface. It allows the control electrode to be positioned close to the emission region for effective control while preventing direct contact with contaminants and liquid buildup.
Solution Approach 2:
The control electrode is positioned in a different dimensional plane relative to the emitter surface, separated by the non-wetting layer thickness. This vertical separation maintains electrical coupling for control functionality while providing physical protection from contamination.
4Productivity
If multiple electrospray emitters are manufactured, then productivity increases, but manufacturing difficulty increases
Solution Approach 1:
Multiple electrospray emitters are merged into a single integrated device structure on one substrate. This allows batch manufacturing of multiple units simultaneously using the same fabrication process, significantly improving productivity while maintaining ease of manufacture through standardized processes.
Solution Approach 2:
The substrate and non-wetting layer serve universal functions across all emitters in the array. This multi-functionality allows a single manufacturing process to produce multiple emitters with identical quality and performance, eliminating the need for separate manufacturing for each unit.
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 design enhances the ease of cleaning and robustness of electrospray emitters, reduces debris accumulation, and improves manufacturing simplicity, while maintaining effective electrospray performance and reducing electrical cross-talk between emitters.
Implementation Method 1
Electrospray occurs when the electrostatic force on the surface of a liquid overcomes surface tension
Implementation Method 2
Electrospray occurs when the electrostatic force on the surface of a liquid overcomes surface tension
Implementation Method 3
an insulating or non-wetting or liquid repellent layer on the emitter surface of the sheet. This non-wetting or liquid repelling layer may make the device easier to maintain and clean by repelling the liquid away from the aperture on the emitter surface
Data Source
AI summary
An electrospray emitter (10) for emitting a liquid comprising a sheet (40) having a channel (65) opening to an aperture (55) on a flat emitter surface extending across the sheet (40). A charging electrode (80) coupleable to an electrical supply and arranged to apply an electrical charge to liquid passing into the channel (65). A control electrode (50) proximal to the channel (65) for controlling electrospray emission, that may be embedded in the sheet. A non-wetting or insulating layer (30) may be applied to the sheet.