I can see a combination of very flexible membrane with small enough balls that the valve would close on the string, but open for the balls, and not leak much.
But even a perfect seal would not be adequate for this to work. Each ball (on the way up) has to push against both the water column and the valve.
That illustration has one more problem than the first. The water in the tank will push against the balls emerging in the downward direction, causing even more energy loss.
You win one interweb. The point of this experiment is to demonstrate that friction is not the main impediment to creating an infinite energy device. The universe is.
Right. SpyOne’s error is ignoring the “machine” part of perpetual motion machine. If all you want is perpetual motion and you are able to truly eliminate all friction, then yes, his bicycle wheel can achieve perpetual motion. But when you turn it into a machine by connecting it to a load, it’s the universe that kills it, not friction.