Abstract: A method for locally heating objects, in particular thin sheet metal, by charging the objects by means of a plasma ignited between two electrodes. In order to keep the thermal stress of a subject as low as possible outside of the zone to be heated it is provided that the machining such as spot welding or burning through a breakthrough occurs with merely one plasma pulse which is produced by applying a voltage pulse exceeding the arc-over voltage of the gap between the electrodes.

Abstract: A device for supplying voltage to a plasma producer comprising a chamber having an outflow opening, and an anode and a cathode arranged in the chamber, the anode and cathode defining a gap therebetween, the voltage supplying device comprising a charging circuit, a capacitor battery having an input connected to the charging circuit and an output connected to the anode and the cathode, and an ignition set supplying HF signals connected to the anode and the cathode, a maximum voltage supplied by the capacitor battery being smaller than an arc-over voltage of the anode-to-cathode gap.

Abstract: A plasma torch for locally heating an object, which comprises an anode having an axially extending bore, and a cathode having an end section extending coaxially through the bore in the anode and another section passing through a chamber communicating with a gas connection, the anode and the end section of the cathode defining an annular gap in communication with the chamber and forming a nozzle. The anode and the cathode are connected in an electrically insulating manner, a gas source is connected to the gas connection, a voltage supply is connected to the anode and the cathode, the voltage supply delivering intermittent voltage pulses exceeding the arc-over voltage in the annular gap, and a ring encloses the nozzle and projects axially therefrom to define a front chamber between the nozzle and the object upon which the ring is placed.

Abstract: A plasma welding torch comprises a non-consumable electrode arranged in a chamber provided in the torch and having a free flat end face extending substantially perpendicularly to a longitudinal axis of the electrode and having a diameter of 15% to 35% of the maximum diameter of the electrode. An inlet port leads to the chamber for delivering a plasma gas thereto, and an outlet port leads from the chamber to an orifice at an outer end of the outlet port, the outlet port having an interior wall, the electrode having a free tapering end section reaching at least to the outer end of the outlet port, and the interior wall of the outlet port being spaced from, and surrounding, the free tapering end section of the electrode and extending to the orifice substantially parallel to the tapering end section of the electrode.

Abstract: A device with a plasma producer with a chamber (27, 27') which is connected with a gas connection and is penetrated by a cathode (19, 19'), and an anode (15, 15') encompassing the cathode (19, 19') with an annular gap, with the annular gap being in connection with the chamber (27, 27') and the anode (15, 15') and the cathode (19, 19') being in connection with the electric connection lines (6).