Pulsed Non-Thermal Plasma System for Low-Temperature Surface Treatment
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Solution Overview
Problem
Thermal atmospheric-pressure plasmas are limited in their utility due to high temperatures, which restrict their application to materials that can withstand these temperatures, limiting the applicability of atmospheric plasma treatments.
Innovation Solution
A system generating a wide beam of non-thermal, low-temperature (below 50°C) partially ionized plasma using repetitive, fast rising high voltage electrical pulses and a directed high-speed gas flow, where the energy is primarily absorbed by electrons, minimizing waste heat and allowing for tunable plasma properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal atmospheric-pressure plasma is used for cleaning, coating, cutting and joining applications, then effective surface treatments can be achieved, but the high temperatures limit utility to materials that can withstand those temperatures
Solution Approach 1:
The patent changes the fundamental parameter of plasma temperature by using pulsed voltage (e.g., 10 kV pulses at 1 kHz repetition rate) instead of continuous AC power, creating non-thermal plasma with electron temperatures much higher than gas temperature. This allows effective plasma chemistry while maintaining low bulk gas temperature (near room temperature), enabling treatment of temperature-sensitive materials
Solution Approach 2:
The patent employs periodic pulsed voltage applied to the plasma generator instead of continuous power delivery. The pulsed nature (e.g., nanosecond to microsecond duration pulses with specific repetition rates) creates non-equilibrium plasma conditions where energy is deposited in bursts, allowing control over plasma chemistry while limiting thermal accumulation, thus treating materials that cannot withstand continuous high temperatures
2Temperature
If fast rising high voltage pulses are used to generate non-thermal plasma, then low temperature plasma can be achieved, but the system complexity increases
Solution Approach 1:
The patent introduces a pulsed voltage generator as an intermediary device between the power source and plasma electrode, along with a flow controller for the carrier gas. These intermediary components enable precise control over plasma parameters (voltage amplitude, pulse width, repetition rate, gas flow rate) to achieve non-thermal plasma conditions while maintaining manageable system complexity through modular design
3Adaptability or versatility
If pulse voltage and repetition rate are adjusted to tune plasma properties, then plasma performance can be optimized for specific applications, but the control complexity increases
Solution Approach 1:
The patent incorporates feedback control mechanisms where plasma parameters (such as active species density, temperature, or treatment effectiveness) are monitored and used to automatically adjust pulse voltage amplitude, repetition rate, or gas flow rate. This feedback loop enables automatic optimization of plasma performance for different applications while simplifying user operation, as the system self-regulates to maintain optimal conditions
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
Enables new chemical pathways in atmospheric pressure plasma treatment, optimizing plasma performance for specific applications by adjusting voltage, pulse repetition rate, and gas flow, achieving effective surface treatments like cleaning, activation, and coating without thermal damage.
Implementation Method 1
repetitive, fast rising (greater than 100 V/ns), short duration (less than 100 nanoseconds), high voltage electrical pulses... The pulses are applied to the moving stream of gas via electrodes located at the plasma head to generate a wide beam of near-room temperature plasma
Implementation Method 2
a directed, high speed flow of gas... A source (e.g., fan, blower, compressor, reservoir of compressed gas) provides a moving stream of gas
Data Source
AI summary
A system for generating and delivering a low temperature, wide, partially ionized tunable plasma stream is described. The system employs a fast rising, repetitive high voltage pulse generator, flowing gas, and a plasma head to produce the described atmospheric pressure plasma stream and its associated active species. The plasma head may have an exit slit with a relatively wide dimension to produce a relative wide plasma stream. Electrodes may be located proximate the exit slit, for example one in an interior of the plasma head via with gas flows toward the exit slit, and the other exterior to the plasma head and offset from the exit slit. The plasma may include baffle material to enhance a uniformity of flow through and across the exit slit. Plasma heads with having exit slit with different widths may be provided as a kit.