Abstract: A toroidal pile of raw material is contained in a toroidal melting pot provided in the lower portion of a furnace and a ring plasma torch is mounted over the toroidal pile of the raw material. A ring plasma arc, driven electromagnetically and rotating azimuthally between the torch and the pile, heats a certain portion of the pile intermittently and periodically. Fine grains are produced in such portion of the pile of raw material that is not heated directly by the plasma arc and collected through a discharge port provided around the major axis of the toroidal melting pot.

Abstract: A metallurgical plasma melting process wherein a plasma burner and a separate start-up burner disposed alongside same in the same port have their axes intersecting in the furnace at an acute angle. Only the start-up burner is operated initially to form a crater in material in the furnace. Thereafter the plasma burner is ignited and the start-up burner is turned off when the plasma burner is operating at full efficiency.

Abstract: A method and apparatus for heating and melting electrically conductive material are disclosed. The method includes the steps of heating a jet of gas or gaseous mixture, directing a heated jet of gas or gaseous mixture to the material, and drawing a diffuse current through said gas jet to said material by seeding it with an additive having a low ionization potential so as to increase the rate at which the material is heated. The apparatus includes means for heating gas(es), means for directing a jet of said gas(es) to the material, means for introducing an additive having a low ionization potential into the gas(es) for purposes of ionizing said gas(es), and means for drawing a diffuse current through the jet of ionized gas to the material.

Abstract: An electric arc heater having outlet gas admission. The mounting flange of an electric arc heater has a channel extending about its circumference which is enclosed by a detachably fastened plate to form a manifold. A passageway for the material to be admitted is provided between an outer surface of the mounting flange and the manifold. A plurality of peripherally spaced passageways are provided in the plate intermediate the manifold and the flow path of the arc heated gas exiting the arc heater outlet providing for the uniform distribution of the added material into the arc heated gas. By varying the position of these passageways a broad range of admission paths ranging from substantially parallel to the flow path of the arc heated gas to substantially perpendicular can be achieved without the use of additional downstream admission collars and seals.

Abstract: The invention relates to a means for electrically heating gases, comprising cylindrical electrodes (2,3) between which an electric arc (20) is generated. Between these two electrodes are arranged one or more spacers (6,7) whose length is from 100 to 500 mm.

Abstract: A thermal plasma generating electrode assembly of the type having a central, water-cooled electrode and an outer sheath defining therewith a path for gas is provided. The sheath is made as a non-water cooled sheath of a high melting, electrically conductive material to avoid damage to the electrode as a result of stray arcing by attracting such stray arcing to the sheath rather than the electrode. In addition the electrode can be retractable within the sheath to enable the latter to be employed for making initial electrical contact with the co-operating electrode of opposite polarity for the purposes of "striking" or initiating the arc upon start-up.

Abstract: Metal bodies such as billets and blooms are reheated for rolling in a metal-refining operation having a blast furnace by first heating the top gas of the blast furnace to at least 800.degree. C. by means of a plasma torch, then, before the gas has cooled appreciably, burning the heated top gas in a preheating chamber. The metal bodies are exposed in the preheating chamber to the heat of the burning and heated top gas. The heated top gas is mixed with combustion-inducing gas to burn it. Before it is mixed with the heated top gas it is preheated by heat exchange with combustion-product gas withdrawn from the preheating chamber. In this manner it is possible to raise the temperature of this combustion-inducing gas to at least 600.degree. C., so that the burners firing the preheating chamber burn clean. In addition much of the heat of the process is recovered, again reducing energy costs for the system.

Abstract: The invention relates to a contact electrode for melting and heating furnaces with DC plasma heating wherein the flow body assures a uniform removal of heat over the entire end surface of the contact electrode, a temperature transmitter signals exceptional thermal loads, and a steel head is metallically connected as wear part to the end surface of the contact electrode.

Abstract: The apparatus includes a microwave generating device and, a waveguide connected with the microwave generating device. A reaction vessel disposed through the waveguide and supplied with a powdery material to be treated with a reaction gas. Pumps are provided for exhausting the reaction vessel. The reaction vessel comprises a vertically elongated vessel having a bottom above which a plasma generating area is formed. In one embodiment, the reaction vessel further comprises a bottom plate horizontally supported in the reaction tube and connected so as to be vertically slidable within the reaction tube.

Abstract: Wafer tray construction for use in a gas plasma reactor. A plurality of the trays are arranged in an array, with an overlap at the adjacent edges of the trays to prevent line-of-sight communication between the trays and ion bombardment of the support on which the trays are mounted. In one disclosed embodiment, the edges of the trays are configured to form the overlap, and in a second embodiment bars inserted between the trays cooperate with the edge portions to form the overlap.

Abstract: The invention relates to a metallurgical plasma melting furnace used for the melting of metals and alloys wherein at least one auxiliary start-up burner for liquid or gaseous fuels is so arranged adjacent to each plasma burner that the hot combustion gases enter into the plasma melting furnace through the same opening in the sidewall of the furnace vessel and melt a crater into the charge material in front of the plasma burner. After the crater has reached a sufficient size, the plasma burners can be reliably operated industrially.

Abstract: A tuyere for injecting hot reducing gases into a furnace is provided with an inlet pipe and a plasma oven whose gas outlet axis is inclined to the longitudinal axis of the tuyere. The angles which the outlet axis of the plasma oven and the inlet pipe form with the said longitudinal axis are such that the longitudinal axis is parallel to the vector sum of the amount of movement of the gases from the plasma oven and the inlet pipe respectively .