DC Plasma Torch Power Control via Gas Flow
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Solution Overview
Problem
The existing DC plasma torches in gas stream treatment apparatuses have a limited operable power range, which restricts their ability to effectively treat gas streams requiring different power levels, as changes in current result in small power variations, while changes in flow rate produce larger power changes, limiting the flexibility in treating diverse gas compositions.
Innovation Solution
The apparatus employs a power control system that varies both the current and flow rate of the source gas to expand the operable power range of the DC plasma torch, allowing for multiple power regimes by controlling the flow rate to achieve larger power changes, thereby accommodating different gas treatment requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the current supplied to the DC plasma torch is increased to achieve higher power, then the power increases only marginally (e.g., 100% current increase yields only 60% power increase), but the device operates closer to its maximum current rating and thermal damage risk
Solution Approach 1:
The invention changes the operating parameters of the plasma torch by varying both current and source gas flow rate. The power control varies current within a first range and source gas flow rate within a second range, allowing the system to achieve a broad operable power range (30-500% of reference power) by combining different parameter combinations rather than relying solely on current increase
Solution Approach 2:
The system dynamically adjusts both current and source gas flow rate based on the desired power level. The power control continuously varies these parameters to maintain optimal operation across different power requirements, enabling the torch to adapt to different gas treatment needs while avoiding thermal damage and discharge quenching
2Power
If the current is increased to treat gas streams requiring higher power, then more power is available for treatment, but the voltage decreases due to the voltage-current characteristics of the DC plasma torch
Solution Approach 1:
The invention compensates for voltage decrease by simultaneously adjusting source gas flow rate. When current increases and voltage decreases, the power control increases source gas flow rate to maintain or increase overall power output, effectively decoupling the voltage-power relationship that normally exists in DC plasma torches
3Power
If the torch operates at maximum current to achieve sufficient power for diverse gas treatments, then power availability increases, but the risk of thermal damage to torch electrodes increases
Solution Approach 1:
The system dynamically selects optimal current and source gas flow rate combinations for each power requirement. Rather than operating continuously at maximum current, the power control adjusts parameters to match the minimum necessary power for each gas treatment task, thereby reducing thermal stress on electrodes while maintaining treatment effectiveness
Solution Approach 2:
The invention uses source gas flow rate as an additional control parameter to achieve power variation without proportionally increasing current. By varying source gas flow rate within a second range, the system can achieve significant power changes (30-500% of reference power) with moderate current changes, reducing thermal load on electrodes
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 configuration extends the operable power range from 30-70% to 300-500%, enabling the treatment of various gas streams with different power needs, including idle and treatment modes, while minimizing electrical energy consumption and avoiding plasma discharge quenching.
Implementation Method 1
a DC plasma torch for generating a plasma flare from a source gas when energised by a source of electrical energy
Implementation Method 2
The plasma causes dissociation of the gas stream into reactive species which can combine with oxygen or hydrogen to produce relatively stable by-products
Implementation Method 3
The plasma causes dissociation of the gas stream into reactive species
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In order to increase the operable range of a DC plasma torch in an abatement apparatus (10), the apparatus comprises a power control configured for controlling the power of the plasma torch by selective control of the plasma source gas flow regulator (24).