Our online catalog is being updated! Please contact us for current pricing. Thermionics Gate Valves Gate Valve Resources: • Options • Ordering Wizard • Pricing and Specifications TLI has manufactured qualified gate valves since 1958. All stainless steel construction Tested against the best gate valves in the world by a national laboratory Judged the only U.S. manufactured valve qualified to meet exacting requirements Improved TogleLok G & TLG Series They offer these additional design features: New design and manufacturing process Fewer bearings exposed to vacuum Longer life bearing interface materials Longer cycle life Lowest particulate levels Lower base pressure No virtual leaks Greatly reduced surface areas Fewer parts exposed to vacuum Smaller internal mechanism Weighs less Seals and opens against atmosphere Seals are easily replaced, lower maintenance costs Theory of Operation TogleLok G & TLG Series TogleLok G and TLG Series valves are toggle action, linear travel gate valves. The gate carriage moves in the valve body on a set of wheels, moved back and forth by a manual or pneumatically-actuated valve stem which passes through a metal bellows. To close the valve, the carriage moves forward on wheels until it reaches the end of the valve case. When the carriage stops, the toggle linkage continues to travel and extend. The gate does not move forward, only upward toward the port seal surface. There is no abrasion or damage to the O-ring. The gate moves up to the port into its sealing position. The O-ring is compressed, making a leak-tight seal. The toggle linkage continues to move forward until the toggle knee passes center and locks, providing positive closure protection in the event control power, or air pressure, is lost.