Planar Micromachined Valve Membrane for Low Dead Volume Pre-Concentrators
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Solution Overview
Problem
Existing pre-concentrator systems for chemical analysis have high dead volumes and reduced concentration factors due to the addition of valves by hybrid integration, which is not suitable for compact systems, and they require multiple components and complex control functionality.
Innovation Solution
A compact, stackable pre-concentrator device with a moveable membrane that serves as both a valve and a thermal desorber, incorporating an adsorption coating on the membrane for dual functionality, reducing the number of parts and simplifying control, using electrostatic operation and electrical heating for efficient desorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If valves are added by hybrid integration to control gas flow, then gas flow control capability is improved, but dead volume increases and concentration factor decreases
Solution Approach 1:
The patent merges the valve function and thermal desorber function into a single integrated component. The moveable membrane serves dual purposes: it acts as a valve to control gas flow and as a thermal desorber to release adsorbed analytes. This integration eliminates the need for separate valve components, thereby reducing dead volume while maintaining gas flow control capability.
Solution Approach 2:
The moveable membrane is designed to perform multiple functions simultaneously. It functions as both a flow control valve and a thermal desorber, allowing a single component to replace what would traditionally require multiple separate components. This multi-functionality reduces the overall device complexity and minimizes dead volume.
2Ease of operation
If multiple valves are used for pre-concentrator operation, then operational control is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into a single integrated component. The moveable membrane integrates the valve function (controlling gas flow) and the thermal desorber function (releasing adsorbed analytes) into one component, reducing the total number of parts while maintaining operational control capabilities.
Solution Approach 2:
The moveable membrane is designed as a universal component that performs multiple operations: it controls gas flow when positioned to open or close the flow path, and it serves as the thermal desorber when heated. This multi-functionality simplifies the device architecture by eliminating the need for separate valve and desorber components.
3Reliability
If trap surface area is increased to maximize efficiency, then analyte retention is improved, but device size increases
Solution Approach 1:
The patent transitions from a traditional three-dimensional trap structure to a planar, two-dimensional configuration. The trap is formed as a flat structure with adsorption coating on the membrane surface, allowing for increased surface area within a compact footprint. This dimensional change enables high analyte retention efficiency without proportionally increasing device volume.
Solution Approach 2:
The patent utilizes porous or chemically reactive materials for the adsorption coating on the membrane. These materials provide high surface area and high analyte affinity within a thin layer, enabling efficient analyte retention without requiring thick or voluminous trap structures. The porous or functionalized surface maximizes contact area for analyte adsorption while maintaining a compact form factor.
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 solution minimizes dead volume and enhances concentration factors by integrating the valve and thermal desorber in a single, low-cost planar assembly, allowing for efficient gas flow control and desorption, thereby improving the detection of chemical species in a compact format.
Implementation Method 1
the membrane is provided with an adsorption coating configured to selectively adsorb the species present in the gas during the flow of gas through the trap
Implementation Method 2
The adsorbed molecules are desorbed, usually by rapidly raising the temperature of the chemically sensitive layer using the heater
Implementation Method 3
heating is carried out electrically
Implementation Method 4
A moveable membrane, which is electrostatically operable, is provided with an adsorption coating
Data Source
AI summary
This invention provides a pre-concentrator device including an electrostatically operated valve and an electrically heated desorber, the electrostatically operated valve comprising a movable flap or membrane carrying a chemically adsorbing coating, suspended by an elastic element above an orifice in an insulated substrate. The device is constructed by planer processing. The flap or membrane can be deflected towards the substrate to block the flow of gas through the orifice by applying a voltage between the substrate and the membrane. The coating provides an adsorbing surface for a volatile organic compound. The coating may be heated electrically, by applying an alternating voltage between the substrate and the flap, thermally desorbing any adsorbed chemical species. When combined with other similar valves in a stacked assembly, the device may be used in a chemical pre-concentrator with very low dead volume.