Electro-osmotic Pump Porous Membrane Flow Pressure
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Solution Overview
Problem
Existing polarisation electro-osmosis pumps face a trade-off between flow rate and pumping pressure due to the size of polarisable elements required, which limits their efficiency in microfluidic applications, especially when small pore sizes are needed for high pressure generation.
Innovation Solution
Incorporating a non-conductive porous membrane in close proximity to the polarisable means within the pump, which enhances the electro-osmotic flow by increasing the thickness of the induced charge layer and allowing for smaller effective pore sizes, thereby increasing flow rates and pressures without sacrificing pumping pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polarisable elements are made larger to increase flow rate, then productivity is improved, but pumping pressure decreases
Solution Approach 1:
The patent introduces a porous membrane as a new structural element with controlled pore sizes (1-100 nm) that is significantly smaller than the polarisable elements (10-100 μm). This porous structure allows the system to achieve high pumping pressure by restricting flow through tiny pores while maintaining high flow rate through the larger polarisable elements, thus resolving the contradiction between flow rate and pumping pressure
Solution Approach 2:
The patent adds a spatial dimension by introducing a porous membrane that creates a separate flow path dimension. The polarisable elements operate in one dimension (micro-scale channels) while the porous membrane operates in another dimension (nano-scale pores), allowing simultaneous optimization of both flow rate and pressure without direct compromise
2Stress or pressure
If polarisable elements are made smaller to increase pumping pressure, then stress or pressure is improved, but productivity decreases
Solution Approach 1:
The porous membrane provides a dual-function structure: its nano-scale pores (1-100 nm) generate high pumping pressure through capillary and electro-osmotic effects, while its high porosity (50-90%) and interconnected pore network maintain excellent fluid permeability, ensuring high flow rate is not compromised
Solution Approach 2:
The system combines two distinct structural components with complementary properties: polarisable elements (10-100 μm) that generate electro-osmotic flow and a porous membrane (1-100 nm pores) that enhances pressure. This composite structure allows simultaneous achievement of high flow rate and high pumping pressure
3Speed
If direct electric field is applied to achieve directed liquid transport, then speed is improved, but object-generated harmful factors increase
Solution Approach 1:
The patent replaces direct electro-osmotic transport (which causes harmful electrochemical reactions) with pressure-driven flow through the porous membrane. The electro-osmotic pump generates pressure indirectly through electro-convection and pressure gradient establishment, rather than direct ionic transport, thereby eliminating gas evolution and concentration polarization while maintaining efficient fluid transport
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 use of a porous membrane enhances polarisation electro-osmotic flow rates by up to ten times and increases pressure by more than ten times, enabling reduced voltage operation, simpler control electronics, and reduced issues with electrochemical reactions and gas formation.
Implementation Method 1
the membrane enhancing the electro-osmotic flow by increasing the thickness of the induced charge layer
Implementation Method 2
Electro-osmosis of the second kind acts on ions within a space charge region (SCR) associated with the surface
Implementation Method 3
the membrane comprising pores extending in a direction at least partially parallel to the longitudinal axis of the passageway and having a pore size smaller than the at least one pore formed by the polarisable means
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A pump for inducing liquid movement by means of polarisation electro-osmosis, comprising a passageway forming a flow path for fluid transport, at least one polarisable means located within said passageway so as to form at least one pore through said passageway, the at least one polarisable means being shaped such that at least a section of the pore walls are curved or inclined with respect to the longitudinal axis of the passageway, the pump further comprising a non-conductive porous membrane positioned across the flow path and in close proximity to the at least one polarisable means, the membrane comprising pores extending in a direction at least partially parallel to the longitudinal axis of the passageway and having a pore size smaller than the at least one pore formed by the polarisable means.