RELIABLE UHV GATE VALVES.

Magnetic containment fusion studies require ultrahigh vacuum systems operating in the 10** minus **7 to 10** minus **8 Pa (10** minus **9 to 10** minus **1**0 torr) range. But components used in the vacuum system also must meet other constraints, one being long-term reliability. Turbomolecular pumps have been improved to where they can meet reliability requirements. But they must be able to operate in a system without problems that can be caused by gate valves - contamination, seal leakage, or other related deficiencies. Basically, two types of gate valves are readily available: linear travel gate valve; and the swinging gate valve. The author discusses problems with these valves, and discusses a patented design valve that solves these problems.