The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 11, 1980
Filed:
Feb. 16, 1977
Werner Oppel, Cologne, DE;
Klockner Ionon GmbH, Cologne, DE;
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. 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.