Low Flow Plasma Torch with Flat Plate Electrode

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Solution Overview

Problem

Inductively coupled plasma devices with helical coils suffer from non-homogeneous current distribution and variable temperature, affecting sample excitation and ion trajectory, and lack flexibility in controlling the induced current and plasma/sample excitation.

Innovation Solution

A low flow plasma torch with a bendless outer tube and an auxiliary tube longer than conventional designs, featuring multiple bendless slots and a flat plate electrode, which sustains a plasma with a reduced gas flow rate, enhancing temperature distribution and plasma stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a helical solenoid is used to generate plasma, then plasma can be sustained, but the induced current becomes non-homogeneous and temperature distribution becomes variable

Engineering Contradiction:
Improveplasma temperature distributionVSAvoidsolenoid configuration
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The solenoid is divided into multiple independently controllable segments or zones along its length. Each segment can be controlled to produce a specific current magnitude and phase, allowing the overall current distribution to be optimized for homogeneous plasma temperature while maintaining the benefits of the helical configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a static, uniformly wound solenoid to a dynamic configuration where current in different segments can be independently adjusted in magnitude and phase. This dynamic control enables real-time optimization of the induced current distribution to achieve homogeneous plasma temperature profiles.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a conventional solenoid is used, then plasma generation is achieved, but flexibility in controlling induced current and plasma excitation is limited

Engineering Contradiction:
Improvecontrollability of induced currentVSAvoidcontrol system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The solenoid is segmented into multiple independently controllable zones, enabling flexible control of the induced current distribution along the plasma column. Each segment can be controlled to produce specific current magnitudes and phases, providing adaptability for different plasma conditions and experimental requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system enables independent variation of current magnitude and phase in different solenoid segments, providing multiple degrees of freedom for controlling plasma properties. This parameter control allows optimization of plasma temperature, density, and excitation characteristics for different analytical applications.

Inventive Principle:
Principle #35Parameter changes

3Loss of substance

If high gas flow rate is used in conventional torch, then plasma stability is maintained, but argon consumption increases

Engineering Contradiction:
Improveargon consumptionVSAvoidplasma stability
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The system uses controlled variations in current magnitude and phase across different solenoid segments to optimize plasma confinement and temperature distribution. This enables stable plasma operation at lower gas flow rates by improving the efficiency of energy coupling and reducing plasma losses, thereby reducing argon consumption while maintaining plasma stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates monitoring and control mechanisms that adjust the current distribution in real-time based on plasma conditions. This feedback control enables maintenance of plasma stability at reduced gas flow rates by compensating for changes in plasma properties through dynamic adjustment of the induced current parameters.

Inventive Principle:
Principle #23Feedback

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 solution enables efficient operation with reduced argon consumption, improved signal and background emission, and increased sample volume introduction, while maintaining or exceeding detection limits compared to conventional systems.

Implementation Method 1

a flat plate electrode means for providing a loop current along a radial plane of the torch

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

sustains a plasma with a reduced gas flow rate

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

providing energy to the torch from the at least one plate electrode

Methodology Applied
Scientific EffectElectromagnetic heating: Dielectric Heating

Data Source

PatentEP2566650B1Inductive devices and low flow plasmas using them
Publication Date: 2019.10.02 REVVITY HEALTH SCIENCES INC
  • EP2566650B1 patent drawingFigure 1A~2B
  • EP2566650B1 patent drawingFigure 3
  • EP2566650B1 patent drawingFigure 4

AI summary

Certain embodiments described herein are directed to devices that can be used to sustain a low flow plasma. In certain examples, the low flow plasma can be sustained in a torch comprising an outer tube and an auxiliary tube within the outer tube. In some examples, the auxiliary tube comprises an effective length to match the shape of a low flow plasma sustained in the torch using a flat plate electrode. Methods and systems using the torches are also described.