A High-Pressure Inductively Coupled Plasma Torch

1987 ◽  
Vol 41 (4) ◽  
pp. 654-657 ◽  
Author(s):  
Thomas R. Smith ◽  
M. Bonner Denton

An inductively coupled plasma (ICP) torch utilizing an extended coolant tube that tapers down to a small exit orifice designed to increase the pressure within the ICP torch is described. This torch design makes use of the advantages associated with higher torch operating pressures (including improved detection limits, increased sensitivity, and better plasma stability), without requiring major modifications to existing commercially available ICP torch box and matching networks. Detection limits obtained with the use of the new torch design are compared with those obtained from several commonly used torch designs using a commercially available torch box and spectrometer. A two- to sevenfold improvement in detection limits is observed through increasing torch operating pressure from 101.325 KPa (760 Torr, or atmospheric pressure) to 120 KPa (900 Torr).

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 834
Author(s):  
Nan Yu ◽  
Renaud Jourdain ◽  
Mustapha Gourma ◽  
Fangda Xu ◽  
Adam Bennett ◽  
...  

This paper focuses on the power dissipation of a plasma torch used for an optical surface fabrication process. The process utilizes an inductively coupled plasma (ICP) torch that is equipped with a De-Laval nozzle for the delivery of a highly collimated plasma jet. The plasma torch makes use of a self-igniting coil and an intermediate co-axial tube made of alumina. The torch has a distinctive thermal and electrical response compared to regular ICP torches. In this study, the results of the power dissipation investigation reveal the true efficiency of the torch and discern its electrical response. By systematically measuring the coolant parameters (temperature change and flow rate), the power dissipation is extrapolated. The radio frequency power supply is set to 800 W, E mode, throughout the research presented in this study. The analytical results of power dissipation, derived from the experiments, show that 15.4% and 33.3% are dissipated by the nozzle and coil coolant channels, respectively. The experiments also enable the determination of the thermal time constant of the plasma torch for the entire range of RF power.


Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 133 ◽  
Author(s):  
Sangeeta Punjabi ◽  
Dilip Barve ◽  
Narendra Joshi ◽  
Asoka Das ◽  
Dushyant Kothari ◽  
...  

In this article, electrical characteristics of a high-power inductively-coupled plasma (ICP) torch operating at 3 MHz are determined by direct measurement of radio-frequency (RF) current and voltage together with energy balance in the system. The variation of impedance with two parameters, namely the input power and the sheath gas flow rate for a 50 kW ICP is studied. The ICP torch system is operated at near atmospheric pressure with argon as plasma gas. It is observed that the plasma resistance increases with an increase in the RF-power. Further, the torch inductance decreases with an increase in the RF-power. In addition, plasma resistance and torch inductance decrease with an increase in the sheath gas flow rate. The oscillator efficiency of the ICP system ranges from 40% to 80% with the variation of the Direct current (DC) powers. ICP has also been numerically simulated using Computational Fluid Dynamics (CFD) to predict the impedance profile. A good agreement was found between the CFD predictions and the impedance experimental data published in the literature.


2014 ◽  
Vol T161 ◽  
pp. 014008 ◽  
Author(s):  
Hanene Bahouh ◽  
Saida Rebiai ◽  
David Rochette ◽  
Damien Vacher ◽  
Michel Dudeck

1977 ◽  
Vol 31 (5) ◽  
pp. 434-443 ◽  
Author(s):  
Charly D. Allemand ◽  
Ramon M. Barnes

Plasma torch design and shapes were studied to facilitate ignition, to concentrate the sample into a narrow central channel, to raise the sample to excitation temperatures with optimized efficiency, and to avoid clogging by organic samples such as residual oil. Observation of the influence of the torch configuration on ignition emphasized the importance of the shape and rate of the gas flows. Operating conditions of torches with diameters from 7 to 18 mm were calculated using a computer model, and predicted operation of small diameter torches requires high magnetic flux density. Experimental verification of an improved torch design demonstrated a higher efficiency, a lower gas consumption, and an easier ignition than conventional configurations.


1981 ◽  
Vol 35 (5) ◽  
pp. 493-497 ◽  
Author(s):  
Steven K. Hughes ◽  
Robert C. Fry

Inductively coupled plasma (ICP) excitation of the 9212.91 Å nonresonant line of atomic sulfur is reported and is found to yield a detection limit more than 20-fold better than any visible or “air path” ultraviolet sulfur lines produced by the argon ICP. The ICP excited spectrum reported here for the element sulfur is markedly different from that reported for atmospheric pressure microwave-induced helium plasmas. Partial Grotrian diagrams and tables of relative intensities, detection limits, and corresponding wavelengths of 30 ICP excited, nonresonant atomic sulfur emission lines and 20 ICP excited, nonresonant atomic carbon lines are presented for the air path, photomultiplier accessible region 2000 to 9900 Å. No lines of ionized sulfur were observed in the 27-MHz, 1.75-kW argon ICP. Vertical emission intensity profiles of near infrared S(I) and C(I) lines are presented for both conventional and extended ICP torches. The present near infrared (S(I) 9212.91 Å and C(I) 9094.83 Å) detection limits for sulfur and carbon are 0.006 μg and 0.13 μg, respectively, using 8 μL gas sampling loop injections of H2S and CH4 into a low-volume transfer line leading directly into the ICP.


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