DUAL-WALLED EXHAUST TUBE FOR VACUUM PUMP

摘要

A dual walled exhaust assembly (28) is provided for an ion implantation system for connecting system components residing at differing voltage potentials . The assembly comprises a disposable corrugated inner tube (84) connected between inner mounting portions of a first end mount and a second end mount and a permanent outer tube (82) connected between outer mounting portions of the fir st and second end mounts. The inner and outer tubes (84 82) are constructed from polytetrafluoroethylene (PTFE) or some similar dielectric material with appropri ate non-flammable properties. The inner corrugated surface of the tube (84) has a plurality of surfaces which are pitched downwardly toward an axis (87) of the in ner tube to prevent contaminant accumulation. The corrugated surface also reduces th e risk of arcing between the system components residing at differing voltage level s by effectively increasing the length of the ground path that a leakage current woul d need to traverse across the length of the tube. The outer tube provides a containment mechanism for containing the toxic effluent if the thinner inner wal l should puncture perhaps due to electrical discharge which might still occur as a result of contaminant build-up on the inner surface of the inner tube.