Why the potential energy is unlimited?

[Zhang Yalin]

I have no more pictures. If you have any trouble in doing my experiment, I would like to solve it.

[FreeEnergy]

solve it

[TinselKoala]

Yalin, your "experiment" is incomplete.
Unless you specify how to get work out of the system, or how to measure any suspected "energy gain", we will just have to rely on ALL THE EXPERIMENTS ALREADY DONE that show your operating principle to be incorrect.

What's the matter--why don't you do your experiment yourself and report the results. Surely ballons and buckets of water can't be that hard for you to get.

And what about the idea of not using the balloon at all and putting a valve in the top of the cylinder--you haven't said whether you realize that is equivalent to the balloon situation--but of course without the complexities that lead one to make incorrect kinematic analyses.

[Zhang Yalin]

 If in the experiment a ball is used instead of a balloon,
The energy got by the buoyancy of the ball will be 9 times than that we paid.
but the ball can't  be taken out because the air in the ball can't be released in no way.
So the experiment can't continue.
The point  is how to take out  the ball of the device without doing any work.
Therefor, a special  balloon must be used but not a ball.

[TinselKoala]

You cannot deflate the balloon without doing work. The water in the column tries to reach its own level with the water in the pan. It can't do so because the system is airtight. When you introduce the balloon into the column from the bottom, not only are you lifting up an equal volume of water to the top of the pan, thus doing work against gravity, but when the balloon reaches the top of the column the weight of the water in the column will create a "suction" that will resist the attempt to deflate the balloon with "splints" or otherwise. To deflate the balloon you will have to, once again, lift up an equal volume of water to the top of the column to reset the system to its initial state. It doesn't matter how much work you are getting out of the balloon, because you are forgetting about the work it takes to lift all that water, twice, per each cycle.