|Overall Diameter||120 mm|
|Bolt Hole Circle||107.5 mm|
|O-Ring Diameter||85 mm|
|Flange Outer Diameter||96.5 mm|
|Thru Bore Diameter||3″ or ~76mm|
Here are some butterfly damper valves for high vacuum use. We are not sure what these were for. The valve isn’t designed to fully seal off the port, just inhibit flow. There were infrared heaters located behind this valve so its possible it just was used to block the IR radiation and certain times during the process.
Location; C 1708 14-4ListC