Abstract: A method of continuously overheating large volumes of gas wherein a gas flow is heated in a cylindrical pipe by means of an electric arc generated between two electrodes arranged in the pipe and axially spaced from each other, the gas being introduced in the tube at a speed of 15-100 m/s and supplied with a quantity of energy amounting to 0.1-0.5 kWh/m.sup.3.

Abstract: The invention relates to a method and a means for facilitating the replacement of plasma generators and for minimizing the heat losses during installation of a plasma generator in a shaft furnace, particularly for plasma generators of the type comprising cylindrical electrodes between which an electric arc is generated, the bases of the arc being caused to rotate by means of electric field coils arranged around said electrodes. To achieve this at least the field coil (7) surrounding the electrode nearest to the nose (12) of the plasma generator, together with its connections for coolant and electricity, is permanently secured in the wall (1) of the shaft furnace in conjunction with the opening (6) for insertion of the plasma generator (11) into the shaft furnace.

Abstract: A method of and apparatus for effecting rapid, reliable and risk-free, pressure-tight connection of a plasma generator to a reactor, such as a shaft furnace for metal oxide reduction. First electrical contact means arranged on a plasma generator, substantially enclosed by a cover, automatically connect the plasma generator to stationary second contact means when the plasma generator is moved by remote-control to a fully installed operating position from a partially installed sealing position in which the plasma generator has its front end partially inserted in the reactor tuyere and seals the reactor. A remote-controlled valve, which seals the reactor from the surroundings when the plasma generator is in an outer completely retracted position, is opened once the plasma generator is in its sealing position, after which the plasma generator is moved to its operating position.

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: The invention relates to a method and plant for converting waste material containing and/or comprising thermally disintegratable chemical substances to stable final products such as CO.sub.2, H.sub.2 O and HCl, the waste material being subjected to a plasma gas of high temperature generated in a plasma generator in order to effect disintegration.The waste material in feedable form is caused to flow through a reaction zone, heated by a plasma gas to at least 2000.degree. C. The reaction zone comprises a cavity burned in a gas-permeable filling in piece form arranged in a reaction chamber, by means of the plasma jet from the plasma generator directed towards and projecting into said filling. An appropriate oxygen potential is maintained in at least the reaction zone such that the disintegration products are continuously converted to stable final products.