Spark Chamber Constant Cross Section Debris Removal

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Solution Overview

Problem

Existing spark chambers for optical emission spectrometry suffer from inefficient debris removal and turbulence in gas flow, leading to contamination, reduced precision, and increased maintenance time due to abrupt changes in gas flow resistance and turbulence.

Innovation Solution

A spark chamber design with a constant unobstructed internal cross-sectional area along the gas flow axis, utilizing a cylindrical shape and a non-rotationally symmetric insulator to maintain laminar gas flow, which efficiently sweeps debris and reduces turbulence, allowing for lower gas flow rates while maintaining effective purging and stable electrical discharges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If gas flow rate is increased to improve debris removal efficiency, then debris clearance is improved, but gas consumption and running costs increase

Engineering Contradiction:
Improvedebris removal efficiencyVSAvoidgas consumption
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The spark chamber is designed with a cylindrical geometry and constant unobstructed internal cross-sectional area along the gas flow axis. This curved/cylindrical shape promotes laminar flow patterns that efficiently transport debris particles from the spark region to the exhaust, maximizing debris removal efficiency while minimizing the gas flow rate required, thus reducing argon consumption and operating costs.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of manufacture

If conventional spark chamber geometry is used with abrupt cross-sectional changes, then manufacturing is simpler, but gas flow turbulence increases reducing analysis precision

Engineering Contradiction:
Improvechamber geometry fabricationVSAvoidspectroscopic analysis precision
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The invention changes the geometric parameters of the spark chamber by maintaining a constant unobstructed internal cross-sectional area along the entire gas flow axis. This parameter change eliminates abrupt cross-sectional transitions that cause turbulence, ensuring laminar flow conditions that prevent debris deposition on optics and maintain high spectroscopic analysis precision throughout the chamber length.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If higher gas flow rates are used to prevent debris deposition on optics, then contamination is reduced, but operating costs increase

Engineering Contradiction:
Improveoptics contaminationVSAvoidargon gas consumption
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The invention utilizes optimized pneumatic flow dynamics by designing the spark chamber with constant cross-sectional area geometry. This design creates efficient laminar flow patterns that effectively sweep debris particles away from the optical path at lower gas flow rates, preventing contamination of mirrors and lenses while minimizing argon gas consumption and reducing operational expenses.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Productivity

If turbulent gas flow is present in the spark chamber, then debris removal may be more vigorous, but electrical discharge stability deteriorates

Engineering Contradiction:
Improvedebris evacuation rateVSAvoidelectrical discharge stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The cylindrical spark chamber geometry with constant cross-sectional area promotes smooth laminar flow patterns rather than turbulent flow. This curved/cylindrical design allows gas to flow smoothly from the spark region along the chamber walls to the exhaust, effectively evacuating debris while maintaining stable electrical discharge conditions necessary for precise spectroscopic analysis.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 design achieves improved debris clearance, reduced downtime for maintenance, and enhanced precision in analysis by promoting laminar gas flow and stable electrical discharges, enabling lower gas flow rates and lower running costs while ensuring accurate nitrogen analysis from the first run.

Implementation Method 1

The argon gas which bathes the sample and the discharge path is utilised to sweep ablated materials including debris from the spark chamber in a continuous or semi-continuous process

Methodology Applied
Scientific EffectGas flow:

Implementation Method 2

A sequence of electrical discharges is initiated between the electrode and the sample, in which the sample acts as a counter electrode

Methodology Applied
Scientific EffectElectrical discharge: Electric Spark

Implementation Method 3

Sample material local to the discharges is vaporised and a proportion of the vaporised atomic material is raised to excited states. On relaxing, the atomic material emits photons, the energies of which are characteristic of the elements in the material

Methodology Applied
Scientific EffectPhoton emission: Luminescence

Implementation Method 4

The spectroscopic analysis is conducted using an optical analyser which usually utilises a dispersive means such as a grating to disperse light spatially according to its wavelength

Methodology Applied
Scientific EffectLight dispersion: Diffraction Grating

Implementation Method 5

A detector, such as an array detector for example, is used to measure the quantity of light as a function of the degree of dispersion

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Implementation Method 6

The presence of an inert gas also prevents oxidation of the sample surface

Methodology Applied
Scientific EffectOxidation prevention:

Implementation Method 7

For analysis of the nitrogen content of a sample, outgassing of residual nitrogen from material at the internal surfaces of the walls of the spark chamber has been found to cause instability of the recorded nitrogen signal

Methodology Applied
Scientific EffectOutgassing:

Data Source

PatentEP2612133B1Spark chamber for optical emission analysis
Publication Date: 2015.11.25 THERMO FISHER SCI ECUBLENS
  • EP2612133B1 patent drawingFigure 1a~1b
  • EP2612133B1 patent drawingFigure 2a~2f
  • EP2612133B1 patent drawingFigure 3

AI summary

A spark chamber (110) for an optical emission analyser, comprising: a gas inlet (125) located on a first side of the spark chamber (110) for supplying a gas into the spark chamber (110); and a gas outlet (135) located on a second side of the spark chamber (110) arranged to convey the gas from the spark chamber (110); wherein an elongated electrode (140) having an electrode axis (142) generally along the direction of elongation is located within the spark chamber (110); and wherein: the first and second sides of the spark chamber (110) lie at either side of the elongated electrode (140) in directions generally perpendicular to the electrode axis (142); there is a gas flow axis (159) through the spark chamber (110) between the gas inlet and the gas outlet; and on passing along the gas flow axis (159) from the gas inlet (125) to the gas outlet (135) the unobstructed internal cross sectional area of the spark chamber (110) perpendicular to the gas flow axis remains constant to within a factor A, wherein A lies between 1.0 and 2.0