Abstract: In an installation for treating workpieces by a glow discharge in a mixture of gases, the gas pressure is detected and valves for the various gases are cyclically and symmetrically opened and closed by amounts relative to the volumetric ratio of the gases.

Abstract: An outer receptacle has at least one opening for receiving an elongated article to be treated and an inner metal container, within the receptacle, is arranged to around only that portion of the article that is to receive treatment. An electrode in and insulated from the metal container is spaced from the article so that the receptacle, container and article can be held at one potential while a different potential is applied to the electrode to produce a glow discharge and heat only that portion of the article within the metal container. The structure also provides for introducing a selected gas into the container and receptacle.

Abstract: In a glow-discharge workpiece-treating system's control system, the existence of a direct short-circuit between workpiece and glow-discharge treatment chamber is ascertained. This is done by comparing a voltage-indicating signal and a current-indicating signal against respective threshold levels, and generating a short-circuit signal when the voltage-indicating signal falls below its threshold level and the current-indicating signal exceeds its threshold level. Preferably, the threshold level for the voltage-indicating signal, although lower than the arc-discharge voltage of the system, is higher than the glow-discharge voltage of the system.

Abstract: The method comprises the measurement of the actual temperature of the workpiece in the container, forming a time derivative value proportional to the rate of change of the measured actual temperature value, comparing the time derivative value with a predetermined or desired treatment temperature value to produce a comparison value and continuously readjusting the glow discharge current proportionally to the comparison value so that no abrupt changes in the glow discharge current takes place.

Abstract: An apparatus for controlling the treatment temperature of a workpiece processed in a current intensive glow discharge container, comprises a differentiator for deriving at its output a time derivative of the actual treatment temperature in the glow discharge container, a comparator for generating a control value corresponding to the difference between the time derivative and a preset desired value, and a current regulator controlled by the control value at the output of the comparator.