Multi-coil induction plasma torch for solid state power supply

Abstract

An induction plasma torch comprises a tubular torch body, a gas distributor head located at the proximal end of the torch body for supplying at least one gaseous substance into the chamber within the torch body, a higher frequency power supply connected to a first induction coil mounted coaxial to the tubular torch body, a lower frequency solid state power supply connected to a plurality of second induction coils mounted coaxial to the tubular torch body between the first induction coil and the distal end of this torch body. The first induction coil provides the inductive energy necessary to ignite the gaseous substance to form a plasma. The second induction coils provide the working energy necessary to operate the plasma torch. The second induction coils can be connected to the solid state power supply in series and / or in parallel to match the impedance of this solid state power supply.

Description

technical field [0001] The present invention relates to induction plasma torches, in particular but not limited to a multi-coil induction plasma torch. Background technique [0002] In an induction plasma torch, a strongly oscillating magnetic field is generated by an induction coil and applied to a gas passing through the coil to ionize the gas to create a plasma. Such plasma torches use the concept of inductive coupling consisting of inductively coupling a radio frequency (RF) field to the flowing gas. The inductive coupling heats the gas to high temperatures, typically 9000°C. At this temperature, the gas transforms into a plasma of positively charged ions and electrons. Plasma torches are generally used in spectral composition analysis, fine powder processing, material melting, chemical synthesis, waste decomposition and similar aspects. These high temperature applications are uniquely associated with plasmas. [0003] Early attempts to generate plasmas by induction ...

AI Technical Summary

Problems solved by technology

[0013] However, solid state power supplies are now characterized by a low frequency operating range (typically between 300 and 400 Hz) and are therefore generally not suitable for the high frequency coil generation required for inductively igniting the plasma. RF signal

Moreover, applications for ignition and operation of plasma torches at atmospheric pressure or under low vacuum conditions have precluded the use of efficient solid-state power supplies

[0014] Moreover, existing dual-coil designs using tube-type oscillator supplies create severe interactions between the control circuits of the two supplies, which can only be resolved by placing a minimum spacing between the two coils

Arranging spacing between the coils seriously affects the uniformity of the temperature field of the generated plasma and directly reduces the efficiency

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