Klockner Ionon Gmbh

Kloeckner Ionon Gmbh

Werner Oppel

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. When used in combination with conventional arc-discharge-responsive switching action, operative for briefly interrupting and then resuming operation in response to each detected arc discharge during normal operation, this can serve to differentiate between arc discharge, which although undesirable is a part of normal operation, and, on the other hand, actual galvanic short circuiting, for which brief interruption of operation constitutes no remedy at all. In a preferred embodiment, the short-circuit detection involves automatic detection of whether the potential difference between the workpiece and the treatment chamber does or does not exceed a threshold level within a predetermined time interval, corresponding to one or several normal-operation brief interruptions of operation.

Method and arrangement for controlling the electrical relationships of a

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.

Method and arrangement for heating workpieces to desired temperatures

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.

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Cologne, Germany

Werner Oppel