Ionizer Asymmetric Voltage Control for Ozone Reduction
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Solution Overview
Problem
Existing ionizers face challenges in reducing ozone generation while maintaining ion balance and shortening the time required to eliminate static charges from workpieces, as reducing negative voltage leads to increased ozone density and reduced ion generation, affecting metal oxidation and charge removal efficiency.
Innovation Solution
The ionizer applies a smaller absolute negative voltage than positive voltage, with a longer application time for negative voltage and a shorter time for positive voltage, alternately generating ions to reduce ozone generation and maintain ion balance, using an ion balance detecting and control system to adjust voltages based on detected ion levels and prevent electrode contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the absolute value of the negative voltage is reduced to decrease ozone density, then ozone generation is reduced, but the field intensity decreases and negative ion generation is reduced, causing ion balance deterioration and increased charge removal time
Solution Approach 1:
The patent applies periodic action by alternately switching between positive voltage and negative voltage at different duty ratios. The positive voltage is applied for a longer duration (60-90%) and negative voltage for a shorter duration (10-40%), creating a periodic cycle that maintains ion balance while reducing ozone generation. This temporal modulation allows the system to achieve both reduced harmful factors and maintained productivity.
Solution Approach 2:
The patent employs parameter changes by adjusting multiple variables simultaneously: the absolute value of negative voltage is reduced to decrease ozone generation, while the duty ratio is modified to compensate for reduced ion generation. By changing these parameters in combination, the system resolves the contradiction between reducing harmful factors and maintaining productivity.
2Object-generated harmful factors
If the absolute value of the negative voltage is reduced to prevent metal oxidation, then ozone generation is reduced, but negative ion generation is reduced, causing ion balance deterioration
Solution Approach 1:
The patent uses periodic action with asymmetric duty ratios to balance ion generation. By applying positive voltage for a longer duration than negative voltage, the system compensates for the reduced negative ion generation caused by lower negative voltage magnitude. This periodic switching maintains overall ion balance while preventing metal oxidation during the negative voltage phase.
Solution Approach 2:
The patent applies the counterweight principle by using positive ion generation to compensate for reduced negative ion generation. The extended positive voltage duration creates an excess of positive ions that balances the overall charge, counteracting the reduced negative ion production and maintaining ion balance stability.
3Stability of the object's composition
If the time period for negative voltage is extended to compensate for reduced negative ion generation, then ion balance is maintained, but the overall cycle time increases, potentially affecting productivity
Solution Approach 1:
The patent optimizes periodic action by using asymmetric duty ratios where positive voltage occupies 60-90% of the cycle and negative voltage occupies 10-40%. This asymmetric periodic action maintains ion balance through extended positive voltage duration while keeping the overall cycle time short, thus preventing significant time loss.
Solution Approach 2:
The patent applies partial action by providing excessive positive voltage duration relative to negative voltage duration. This excessive positive ion generation compensates for reduced negative ion generation without requiring equal time allocation, thereby maintaining ion balance while minimizing overall cycle time and time loss.
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 effectively reduces ozone generation, prevents metal oxidation, maintains ion balance, and quickly eliminates static charges from workpieces, while facilitating electrode maintenance by detecting and adjusting for changes in ion balance and contamination.
Implementation Method 1
as a result of corona discharge occurring at a distal end side of an electrode caused by application of positive or negative voltages with respect to the electrode, positive ions or negative ions are generated inside the static charge eliminating space
Implementation Method 2
Owing thereto, metals (for example, the electrode, etc.) utilized in the ionizer become oxidized and corroded as a result of the generation of ozone by application of the negative voltage
Data Source
AI summary
The present invention relates to an ionizer, a static charge eliminating system, an ion balance adjusting method, and a workpiece static charge eliminating method. In an ionizer, when positive and negative voltages are applied to an electrode, an amplitude Vm of the negative voltage is set to be smaller than an amplitude Vp of the positive voltage, and further, the time Tm for which the negative voltage is applied to the electrode is set to be longer than the time Tp for which the positive voltage is applied thereto.