Or course it all needs the people at the table to buy into it, but:
Continual Light/Flame/Darkness on an object at the bottom of a tube for a directional 'flash(light/dark)'
Firetrap in the same location with a sturdy tube.
Eversmoking Bottle to power machinery.
To show what I mean, the Ring Gates use the term 'put through', which might argue that unattended use will not work. There's also the 100-lb/day limit, which begs the question of what happens to the guy trying to put his 10-lb head through a gate after we've sent 19 5-lb metal ingots through. Asking where the 20th is, you see...
But if the table is in agreement, having the orbital-launch shuttle leave everyday PRECISELY on time as the one hundred pairs of ring gates under it all recharge at once, providing ten thousand pounds of high-pressure gas to the underside of the launch platform...