Abstract: An induction plasma torch comprises a tubular torch body, a plasma confinement tube disposed in the tubular torch body coaxial therewith, a gas distributor head disposed at one end of the plasma confinement tube and structured to supply at least one gaseous substance into the plasma confinement tube; an inductive coupling member embedded within the tubular torch body for applying energy to the gaseous substance to produce and sustain plasma in the plasma confinement tube, and an electrically conductive capacitive shield on an inner surface of the tubular torch body. The capacitive shield is segmented into axial strips interconnected at one end. Axial grooves are machined in the inner surface of the tubular torch body, the axial grooves being interposed between the axial strips.

Abstract: An induction plasma torch comprises a tubular torch body, a tubular insert, a plasma confinement tube and an annular channel. The tubular torch body has upstream and downstream sections defining respective inner surfaces. The tubular insert is mounted to the inner surface of the downstream section of the tubular torch body. The plasma confinement tube is disposed in the tubular torch body, coaxial therewith. The plasma confinement tube has a tubular wall having a thickness tapering off in an axial direction of plasma flow. The annular channel is defined between, on one hand, the inner surface of the upstream section of the tubular torch body and an inner surface of the insert and, on the other hand, an outer surface of the tubular wall of the plasma confinement tube. The cooling channel carries a fluid for cooling the plasma confinement tube.

Abstract: An induction plasma torch comprises a tubular torch body, a tubular insert, a plasma confinement tube and an annular channel. The tubular torch body has upstream and downstream sections defining respective inner surfaces. The tubular insert is mounted to the inner surface of the downstream section of the tubular torch body. The plasma confinement tube is disposed in the tubular torch body, coaxial therewith. The plasma confinement tube has a tubular wall having a thickness tapering off in an axial direction of plasma flow. The annular channel is defined between, on one hand, the inner surface of the upstream section of the tubular torch body and an inner surface of the insert and, on the other hand, an outer surface of the tubular wall of the plasma confinement tube. The cooling channel carries a fluid for cooling the plasma confinement tube.

Abstract: An induction plasma torch comprises a tubular torch body, a plasma confinement tube disposed in the tubular torch body coaxial therewith, a gas distributor head disposed at one end of the plasma confinement tube and structured to supply at least one gaseous substance into the plasma confinement tube; an inductive coupling member embedded within the tubular torch body for applying energy to the gaseous substance to produce and sustain plasma in the plasma confinement tube, and an electrically conductive capacitive shield on an inner surface of the tubular torch body. The capacitive shield is segmented into axial strips interconnected at one end. Axial grooves are machined in the inner surface of the tubular torch body, the axial grooves being interposed between the axial strips.

Abstract: A plasma confinement tube for use in an induction plasma torch is disclosed. The plasma confinement tube defines a geometrical axis and an outer surface. The plasma confinement tube includes a capacitive shield comprising a film of conductive material applied to the outer surface of the plasma confinement tube and segmented into axial strips. The axial strips are interconnected at one end. Axial grooves are machined in the outer surface of the plasma confinement tube, and interposed between the axial strips. The conductive film may have a thickness smaller than a skin-depth calculated for a frequency of operation of the induction plasma torch and an electrical conductivity of the conductive material of the film.

Abstract: A process and apparatus for preparing a nanopowder are presented. The process comprises feeding a reactant material into a plasma reactor in which is generated a plasma flow having a temperature sufficiently high to vaporize the material; transporting the vapor with the plasma flow into a quenching zone; injecting a preheated quench gas into the plasma flow in the quenching zone to form a renewable gaseous condensation front; and forming a nanopowder at the interface between the renewable controlled temperature gaseous condensation front and the plasma flow.

Abstract: An induction plasma torch comprises a tubular torch body, a plasma confinement tube disposed in the tubular torch body coaxial therewith, a gas distributor head disposed at one end of the plasma confinement tube and structured to supply at least one gaseous substance into the plasma confinement tube; an inductive coupling member for applying energy to the gaseous substance to produce and sustain plasma in the plasma confinement tube, and a capacitive shield including a film of conductive material applied to the outer surface of the plasma confinement tube or the inner surface of the tubular torch body. The film of conductive material is segmented into axial strips interconnected at one end. The film of conductive material has a thickness smaller than a skin-depth calculated for a frequency of a current supplied to the inductive coupling member and an electrical conductivity of the conductive material of the film.

Abstract: A process and apparatus for preparing a nanopowder are presented. The process comprises feeding a reactant material into a plasma reactor in which is generated a plasma flow having a temperature sufficiently high to vaporize the material; transporting the vapour by means of the plasma flow into a quenching zone; injecting a preheated quench gas into the plasma flow in the quenching zone to form a renewable gaseous condensation front; and forming a nanopowder at the interface between the renewable controlled temperature gaseous condensation front and the plasma flow.