Self-sterilizing Device Using RF Plasma Fields
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Solution Overview
Problem
Conventional plasma sterilization methods face limitations, particularly at near-atmospheric pressure, where the required electrode spacing for maximum volumetric ionization is impractical for applications like high-speed air vehicles, and traditional sterilization processes are slow compared to plasma sterilization.
Innovation Solution
The development of RF glow discharge using an a.c. voltage potential across electrodes, allowing for the generation of a homogeneous plasma field at frequencies between 3 to 20 kHz and voltages between 2 to 15 kV, which can sustain a plasma field effectively at atmospheric pressure with reduced electrode spacing, and the integration of self-sterilizing surfaces with embedded electrodes that can produce plasma for sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC voltage potential is used across two electrodes for plasma generation, then volumetric ionization can be achieved, but the required electrode spacing becomes impractical at near-atmospheric pressure
Solution Approach 1:
The patent applies periodic action by using RF (radio frequency) alternating voltage instead of DC voltage. The RF voltage oscillates at high frequency (typically 13.56 MHz), creating periodic breakdown and re-ignition cycles that sustain plasma discharge. This periodic excitation allows volumetric ionization to occur at much smaller electrode spacing (millimeter to micrometer range) compared to DC breakdown, resolving the contradiction between achieving volumetric ionization and maintaining practical electrode spacing.
Solution Approach 2:
The patent changes the electrical parameters from DC to RF alternating voltage, and adjusts the frequency and voltage amplitude parameters to optimize plasma generation. By changing the excitation mode from DC to RF and adjusting these parameters, the system achieves sustained plasma discharge at reduced electrode spacing while maintaining volumetric ionization effectiveness.
2Reliability
If traditional sterilization methods are used, then sterilization can be achieved, but the process is slow
Solution Approach 1:
The patent replaces traditional mechanical/thermal sterilization methods (such as autoclaving or chemical sterilants) with plasma-based sterilization. The RF-driven plasma generates reactive species, UV radiation, and ionization that directly inactivate microorganisms on surfaces. This substitution enables rapid sterilization (completing in seconds to minutes) compared to traditional methods that require prolonged exposure times, thereby resolving the contradiction between sterilization effectiveness and speed.
Solution Approach 2:
The patent utilizes phase transitions in the plasma state, where the RF energy excites gas molecules into a plasma state containing reactive species and UV radiation. These reactive species directly destroy microbial cell walls and genetic material, achieving rapid sterilization. The phase transition from ground state gas to excited plasma state enables the high-speed sterilization process.
3Length of stationary object
If RF glow discharge is used to reduce electrode spacing, then practical applications become feasible, but the system complexity increases
Solution Approach 1:
The patent designs the RF plasma generation system with multi-functionality, where the same RF plasma source can be used for various purposes including sterilization, surface treatment, and material processing. The system integrates the RF generator, electrodes, and control circuitry into a compact unit that can adapt to different applications, reducing the need for separate complex systems for each function and thereby managing overall system complexity while achieving reduced electrode spacing.
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 efficient and rapid sterilization of surfaces and objects by generating a plasma field that can eliminate pathogens and contaminants, meeting ISO standards and providing a self-sterilizing capability without the need for user intervention, while being suitable for various applications including medical and food preparation equipment.
Implementation Method 1
a plasma field generated by the device... plasma fields for the purpose of self-sterilization and/or sterilization of another object
Implementation Method 2
Plasma field generation may also include the generation of ionized air, radicals, photons, and/or ultraviolet light
Implementation Method 3
Dielectric barrier discharge (DBD) involves one dielectric coated electrode that is typically exposed at the surface to the surrounding atmosphere
Implementation Method 4
The development of RF glow discharge using an a.c. voltage potential across electrodes, allowing for the generation of a homogeneous plasma field at frequencies between 3 to 20 kHz
Implementation Method 5
The emission of UV light as well as chemical processes in surface plasmas is suitable for decontamination in a short timescale
Implementation Method 6
erosion of the microorganisms due to etching from radicals formed due to plasma ionization
Data Source
AI summary
Embodiments of the invention relate to a method and apparatus for self-sterilizing a surface or other portion of the apparatus and/or sterilizing other objects. Embodiments can utilize self-generated and/or remotely controlled plasma fields for the purpose of self-sterilization and/or sterilization of another object. Embodiments of the invention can have broad applications in procedures and equipment requiring the sterility of devices used for medical procedures, decontamination procedures, drug delivery, sterility of consumer products, and sterility of food preparation equipment and tools.