I'm building a prototype that has a 2 ball valve subassembly. It works like a water lock but with cold gas.1 1/2 dia id with about 75 in lbs (6.25 ft lb) to rotate. So we are looking at 90 deg rotation. Also it would be nice to be able to use just one mechanical source to be cheaper, but I'm starting to think that two actuators would be less complicated. Right now I have a gear mounted on the valve stub of each cvalve, and a drive gear with 90 degrees of teeth to do the turning. But now I'm thinking that maybe I've complicated the thing too much. When the drive gear leaves the valve gear, there is some jolt. And that will not be good long run...and may lead to a possible gear mis-timing. How about some linkage on the valve shaft and some kind of linear actuator? If the lengths and sizes are picked out correctly, it would not need any limit switches and could just bottom out on the actuator. What do you think?