Gliding Arc Discharge Sterilization with Constrained RONS
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Solution Overview
Problem
Existing cold atmospheric plasma technologies for surface and air sterilization face challenges in achieving effective disinfection, particularly in reducing virus viability on dry samples, which is significantly lower compared to UV-C disinfection.
Innovation Solution
The use of a gliding arc discharge apparatus that includes divergent electrodes and a high-voltage power source to generate a gliding arc plasma, which moves between the electrodes and increases the concentration of disinfecting products like nitrogen oxides and hydroxyl radicals, thereby enhancing sterilization effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cold atmospheric plasma is used for decontamination, then heat-sensitive substrates can be treated, but the efficacy for killing viruses on dry samples is significantly reduced compared to UV-C
Solution Approach 1:
The patent changes the physical and chemical parameters of the plasma by using gliding arc discharge to generate higher concentrations of reactive oxygen and nitrogen species (RONS), particularly nitrogen dioxide and hydroxyl radicals, thereby improving viral inactivation efficacy while maintaining cold plasma conditions suitable for heat-sensitive substrates
Solution Approach 2:
The patent employs strong oxidizing agents generated through gliding arc discharge, including high concentrations of RONS such as nitrogen dioxide, hydroxyl radicals, and ozone, which enhance the disinfection capability against viruses on dry surfaces while operating at near-room temperature
2Quantity of substance
If gliding arc discharge is used to increase plasma density and power, then disinfecting product concentration increases, but the plasma extinguishes periodically requiring re-initiation
Solution Approach 1:
The patent utilizes the periodic nature of gliding arc discharge, where the discharge ignites in an ignition region and then glides along the electrode surface, creating periodic bursts of high-concentration RONS that are effectively delivered to the substrate through controlled gas flow
Solution Approach 2:
The patent maintains continuous disinfection action by using gas flow to transport reactive species from the plasma region to the substrate and by continuously re-initiating discharges, ensuring uninterrupted delivery of disinfecting products despite the periodic extinction and re-ignition of the plasma
3Ease of operation
If divergent electrodes are used to create gliding arc discharge, then plasma moves along the electrode path, but the discharge requires increasing power to compensate for volume losses
Solution Approach 1:
The patent concentrates plasma generation in a localized ignition region where high-voltage breakdown occurs, rather than attempting to sustain uniform plasma across the entire electrode gap. This localized approach reduces overall power requirements while still achieving effective disinfection through transport of reactive species
Solution Approach 2:
The patent uses gas flow as an intermediary to transport reactive oxygen and nitrogen species from the plasma generation region to the substrate. This allows the plasma to be confined to a smaller volume with lower power requirements while still treating a larger surface area through the mediated transport of disinfecting species
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 gliding arc discharge technology effectively increases the concentration of disinfecting products, improving the sterilization efficacy for both surfaces and air, while preventing these products from escaping into the ambient air.
Implementation Method 1
The gliding arc discharge is an electrical discharge formed between at least two divergent electrodes powered by a high-voltage power supply and having a plasma gas flowing between the electrodes
Implementation Method 2
The generated plasmas are weakly ionized and lack local thermodynamic equilibrium since the electron energy is much higher than that of the heavy plasma species; they are generally classified as non-thermal plasmas
Implementation Method 3
The discharge initiates with an arc at the shortest gap between the electrodes, after which it elongates and travels along the diverging path between the electrodes as a result of gas flow transverse to the discharge
Implementation Method 4
Operating with humid air as the plasma gas, the species generated include: NO−, OH−, N2+, and O2+, and the nitrogen oxides, NO, NO2+, NO3+, and ONOOH
Implementation Method 5
Nonthermal or cold (nonequilibrium) atmospheric plasmas generated in air in the presence of water vapor produce various radicals and reactive molecules called reactive oxygen and nitrogen species (RONS)
Data Source
AI summary
Apparatus for sterilizing surfaces and apparatus for sterilizing air and enclosed objects using gliding arc discharge technology are described, whereby disinfecting products formed in the discharge are prevented from escaping from the apparatus into the ambient air.