Assembly for monitoring the permeability of an evacuated area

摘要

The arrangement has a device with has an electrical proximity switch (7) connected to an evaluation unit, and metallic bellows (5) hermetically connected with a vacuum area. The switch is placed at a distance in direction of motion of the bellows, where size of the switch is varied based on axial length of the bellows. A fixed pipe (9) connected with a metallic wall (2) is placed around the bellows by adherence of an air gap. The pipe enclosing the bellows in a moisture proof manner is longer than the bellows, and the switch extends opposite to the pipe.