Arrangement for treating workpieces by corona discharge with short-circuit prevention feature

Abstract

Short-circuit prevention is provided in an arrangement for measuring temperatures of workpieces to be nitrided. An electrical potential gradient is established between a workpiece and a container in which the workpiece is accommodated so as to heat the workpiece and concomitantly produce in the circumambient region of the workpiece a corona discharge field of ionized particles. In order to measure the temperature of the workpiece, a heat sensor is mounted in the workpiece and extends along a path from the workpiece through the field of particles in the circumambient region and thereupon to the exterior of the container. Due to the presence of the heat sensor in the field, metal particles spattered from the workpiece tend to deposit themselves along the heat sensor. In time, a continuous electrically-conductive path would form intermediate the container and the workpiece which would result in short-circuiting between the former and the latter and thus would lead to the discontinuance of the electrical potential gradient. The invention provides a short-circuit prevention system which prevents desposition of the particles at selected portions of the path so as to avoid any possibility of discontinuance of the electrical potential gradient.

Dependencies are inferred from the claim text.