Microfluidic Gas Mixing Circuit for Low Carrier Gas Consumption
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Solution Overview
Problem
Existing methods for generating gas mixtures for air quality analysis instruments require high flow rates and carrier gas consumption, leading to significant losses and reduced portability due to the weight of equipment and bulky gas cylinders.
Innovation Solution
A method using a gas mixture generator with at least two inlets, a microfluidic circuit, and solenoid valves to control the flow and mixing of carrier gas and pollutant, allowing for low flow rates and reduced carrier gas consumption, featuring a system that cleans the circuit with pure air, forms and mixes air trains with added pollutants, and adjusts pressure to achieve the desired mixture concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional methods are used to generate gas mixtures, then the required flow rates and concentrations can be achieved, but the device weight increases and carrier gas consumption increases
Solution Approach 1:
The device is divided into separate functional modules: a microfluidic chip for precise mixing, a pollutant reservoir for controlled delivery, and a carrier gas inlet. This segmentation allows each component to be optimized independently, reducing overall device weight while maintaining low carrier gas consumption through efficient microfluidic mixing channels.
Solution Approach 2:
The invention utilizes microfluidic pneumatic principles to control gas flow and mixing at the microscale. By employing pressure-driven flow through microchannels, the system achieves precise concentration control with minimal carrier gas consumption, eliminating the need for bulky flow meters and high-flow rate equipment that would increase device weight.
2Quantity of substance
If high flow rates of carrier gas are used to obtain low pollutant concentrations, then the desired mixture can be generated, but carrier gas loss increases and device portability decreases
Solution Approach 1:
The microfluidic chip employs pressure-driven pneumatic flow to precisely control the mixing of carrier gas and pollutant at the microscale. This allows accurate concentration control with carrier gas flow rates as low as 10-100 mL/min, dramatically reducing carrier gas loss compared to conventional high-flow rate systems while maintaining portability.
Solution Approach 2:
The system changes the operating parameters from high flow rates to low flow rates by utilizing microfluidic mixing efficiency. The microchannel geometry and pressure control enable effective mixing at reduced flow rates, achieving the same concentration control precision with significantly lower carrier gas consumption and minimal loss.
3Quantity of substance
If conventional gas mixture generation devices are used, then the required concentrations can be achieved, but the equipment becomes bulky and non-portable
Solution Approach 1:
The device is segmented into compact functional units: a small microfluidic chip (few cm³), a minimal pollutant reservoir, and simple gas inlet/outlet connections. This segmentation eliminates the need for bulky conventional components such as large flow meters, complex mixing chambers, and heavy gas cylinders, achieving precise concentration control in a portable format.
Solution Approach 2:
The invention replaces bulky mechanical flow control devices with microfluidic pneumatic control. The microchannel network and pressure-driven flow enable precise concentration control without requiring large external flow meters or complex mechanical assemblies, dramatically reducing device volume while maintaining accurate gas mixture generation capability.
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 approach enables the generation of gas mixtures with low carrier gas consumption and weight, improving portability and efficiency by optimizing the flow and mixing process, resulting in a more effective and portable gas mixture generation system.
Implementation Method 1
a system of solenoid valves, a microfluidic circuit and a mixing cell, the microfluidic circuit comprising a sub-circuit which can be isolated or connected to the mixing cell thanks to the system of solenoid valves
Implementation Method 2
a mixing cell... sending of a second train of air to the mixing cell... until the desired quantity of gaseous mixture is obtained at the outlet of the mixing cell
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
Method for generating a gas mixture by means of an apparatus comprising at least two inlets, the first of which is an inlet for a carrier gas (IN1) and the second of which is an inlet for a pollutant (IN2, IN3) and at least one gas outlet (OUT_MEL), a solenoid valve system (E3, E4, E6, E21, E22, E23, E24, E25, E31, E32, E33, E34, E35), a microfluidic circuit (CMF) and a mixing cell (C_MEL), the microfluidic circuit comprising a sub-circuit (SC) which can be isolated or linked to the mixing cell by means of the solenoid valve system, characterised in that it comprises the following steps: a) cleaning the microfluidic circuit with pure air received at the first inlet; b) forming a first air stream (TRAIN1) with a gas received at the first inlet of the apparatus, sending said first air stream to the mixing cell and adding a pollutant in the isolated sub-circuit of the mixing cell from at least one pollutant received at the second inlet of the apparatus; c) opening the sub-circuit with the solenoid valve system, such that the sub-circuit is connected to the first inlet of the apparatus supplied with gas and to the inlet (IN_MEL) of the mixing cell, the opening of the sub-circuit causing a second air stream (TRAIN2) to be sent to the mixing cell; steps b) and c) being repeated until the desired quantity of gas mixture is obtained at the outlet (OUT_MEL) of the mixing cell.