Vacuum treatment apparatus

A vacuum treatment apparatus, comprising:

• a vacuum recipient for containing an atmosphere;
• means for generating electrical charge carriers in the atmosphere within said recipient, the electrical charge carriers being of the type that form electrically isolating material;
• a work piece carrier arrangement in said recipient;
• at least two electroconductive surfaces in said recipient which are mutually electrically isolated from each other;
• a DC power supply operationally connected to said at least two electroconductive surfaces by respective electrical conductors with an inductor in one of said conductors;
• a parallel switching arrangement connected between said electrical conductors to control a current path between said conductors;
• and
• said parallel switching arrangement comprising a controlled adjusting unit with a time-controlled discharge or charge current loop operationally bridging said electroconductive surfaces and having a high ohmic resistance during first time spans and a lower ohmic resistance during second time spans, so that a voltage between said electroconductive surfaces, due to electrical charge carriers in said atmosphere, may be discharged through said current loop during said second time spans, and with a timing unit connected to a timing input of said time controlled current loop for controlling said first and second time spans to occur repetitively so as to prevent arcing at parts of said electroconductive surfaces which are or which are becoming electrically isolated from said atmosphere by some of said electrical charge carriers depositing as insulating material thereon.

A vacuum treatment apparatus, comprising:

• a vacuum recipient for containing an atmosphere;
• means for generating electrical charge carriers in the atmosphere within said recipient, the electrical charge carriers being of the type that form electrically isolating material;
• a work piece carrier arrangement in said recipient;
• at least two electroconductive surfaces in said recipient which are mutually electrically isolated from each other;
• a DC power supply operationally connected to said at least two electroconductive surfaces by respective electrical conductors with an inductor in one of said conductors;
• a parallel switching arrangement connected between said electrical conductors to control a current path between said conductors;
• and
• said parallel switching arrangement comprising a controlled adjusting unit with a time-controlled discharge or charge current loop bridging said electroconductive surfaces and said DC power supply, said discharge or charge current loop being controllably switchable to have a higher ohmic resistance during first time spans and a lower ohmic resistance during second time spans, and further comprising a timing unit connected to a timing input of said controlled current loop and controlling said first and second time spans to occur repetitively so as to prevent arcing at parts of said electroconductive surfaces which are or which are becoming electrically isolated from said atmosphere by some of said electrical charge carriers depositing as insulating material thereon.